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Home My WebLink About16523 Smokey Point Blvd_PWD2024_2026 COM MUNITY DEVELOPMENT DEPARTMENT e 80 Columbia Avenue o Marysville, WA 98270 (360) 363-8100 o (360) 651-s099 FAX oi',1 August 29,2019 TerraVista NW, LLC Attn: Eric Scott 3204 Smokey Pt Dr, Suite 207 Arlington, WA 98223 Re: Letter of Utility Availability (UA19-004) for Proposed Utility Trailer Sales Dear Mr. Scott, Your request for 'utility availability' has been approved for city water and sewer service to a proposed sales lot and associated buildings located at 16517 Smokey Point Blvd, Arlington, WA (Parcel #310528-002-0ll-00 & 2-044). This approval will expire in one year on August 29, 2020. If the water/sewer connections cannot be completed within one year or if the plans change, a new application must be submitted. If an extension is necessary, please notify this office prior to the expiration date and the $250.00 application fee will be waived. Submit civil water/sewer plans to Shane Whitney, Civil Plan Reviewer, for review. He can be reached at 360-363-8227 or swhitney@marysvillewa.gov. See attached memo for pressure and fire flow information. For utility record drawings, contact Chien Chang at 360-363-8247 or cchan g@marysvillewa. gov. Capital improvement fees will be due at building permit issuance. Please include a copy of the City of Arlington building permit with your utility application. If you have any questions, please contact me at 360-363-8224 or dvangelder@marysvillewa.gov. Sincerely, Douglas van , P.E Engineering Services Manager Cc: Jeff Laycock, P.E., City Engineer Shane Whitney, Civil Plan Reviewer City of Arlington DvG/dt CITY OF MARYSVILLE - CDIPW DEPARTMENTS UTILITY AVAILABILITY REVIEW Tracking #: UA19-004 Received By: DT Date Received: B/16/L9 Date Returned: Applicant: Terra Vista NW Engineers, Arlington, WA proposal/Location: Commercial utility trailer sales at 76517 /L6523 SP Blvd, Arlington, WA Parcel #310528-002-01L-00 & 2-044. Site is within Requirements: Submitted Yes No Yes No Yes No Status City Limits X Annexation Petition X USA (sewer) X Annexation X Covenant CWSP (water) X Adjacent to City X Limits UGA (annex) X Within two parcels X of City Limits SEWER Size and location: 12" PVC located in SP Blvd Record Dwg #: 5-543 1987 Main Fees: None Re Fees: CRC#262 - S0.036/sf of ro e LID/ULID: ULID 1 WATER I Size and location: 12:E.6ated in SP Blvd Record Dwg#: W-775 (1965) i rr--l--79> Main Fees: 52.25llf (Paid) Recovery Fees: None Static Pressure PSt Residual (PSl): 4 V Available Fire Flow (GPM): a=4 GPM @ 20 PSI: J555 HYD Model or Actual Flow Oc*rs..0 Other PUBLIC WORKS APPROVAL nt City EtfAineer;r,leff /4 L. Laycock, PE Sign:L I Date: I 1 ,A.'t YUF COMMUNITY DEVELOPM ENT DEPARTMENT lMe itte 80 Columbia Avenue o Marysville, WA 98270 (360) 36s-8'100 o (360) 651-5099 FAX iNGT0l'i www.marysvillewa.gov WAT ER/ SEWER APPLI CAT I ON FOR COMMERCIAL/ INDUSTRIAL PROJECTS (Requires 48 hts notice for processing) SITE INFORMATION Proiect Title Ptoject No: Site Address: Building Permit No: (Attach copy) Tax Patcel No Attach Site Plan: Show meters, check valves, sewer connections. grease traps & storm connections. OWNER/APPLICANT Name: Company: Address Ciw/State/Zip Phone (office) Phone (cell) E-mail: Utilitv Billing Addtess: WATER/SEWER/STORM 1) Tvpe of Use: Blde SF Lot SF I Retail Sales/Manuf/Church,/Scho ol f D aycare I O ffrce/Me diczl / D ettal / Nursing Home/Other ! Restaurant/Tavern/Espresso I Warehouse/Stotage n Hotel/Motel - Rooms RV Pads 2) Twe of Fire Ptotection: -t n Fire Sprinkler System n Fire Depattment Connection (FDC) r Fire 150 ft for within 300 ft in residential 3) Size of Water Meters/Settets: Domestic Irtigation Fite Service Tap bv CiW ot Contractor a 5/8" (approx 20 qpm) E t/0" (approx 30 gpm) . 1" (approx 50 gpm) r: 71/2" (apptox 100 gpm) a 2" (approx 160 gpm) o 3",4",6", or 8" (circle), (>300 gpm) 4) Sewer Connections: 6) Onsite impervious sutface atea: I New r Repair Ll lJemo nSF 3200sfERU 5) Storm Connections to City System: Admin Fee: tr Qtv- For Aqency Use: Estimated Total $ Owner or Authorized Agent: Date MM(l 14.01.030 Print: UTILITY CAPITAL IMPROVEMENT CHARGES - 2019 itte MMC Section 14.07.010 - Marysville I Ord. Nos. 2607 &2670 - Effective 1-1-2006 i\(i={rr, Community Development Department 80 Columbia Avenue r Marysville, WA 98270 (360) 363-8109 o 1360) 651-5099 FAX o Office Hours: Monday - Friday 7:30 AM - 4:00 PM RESIDENTIAL UNITS Water Sewer Type of Connection City Outside City Citv Outside City Residential DU* Eff uU06 $4,75O/du $5.49O/du $4,490/du $4,890/du Inspection Plumb permit varies Plumb permit $ 100 $100 Admin/Filing Fee $20 $20 $20 $20 *Dwelling unit includes single-family, multi-unit housing, apts, condos, manufactured homes and mobile homes. Main fees or latecomer fees on location. Water Sewer Type of Connection City Outside City City Outside City Hotel/Motel Eff UU06 $1,816/rm $2.099/rm Sl.717lrm $1,870/rm RV Park Pads Eff r/U06 $2.375lpad 52.745lpad $2,245/pad $2,445lpad COMMERCIAL / INDUSTRIAL WATER Gallons per Minute City Outside City 0 - 2000 epm $1.64 /square foot (blde) $ I .99 / square foot ftlds) 2001 - 4000 epm $2.40 / sf $2.87 / sf 4001+ gpm $3.16 / sf $3.80 / sf Warehouse/Storage (ord No. 3026, Eff 7/15/16) $0.48 / sf $0.65 / sf (25o/o rate reduction for fire sprinklers) SEWER Type of Use City Outside City Retail Sales/Manufacturing/ $ 1.03 / square foot (bldg) $1.24 lsquare foot (bldg) Churches/Schools/Day Care Offi ces/Medical/DentalA'{ursing Homes $1.67 / sf $2.00 / sf and all other uses not listed Warehouses/Storage $0.49 / sf $0.65 / sf Restaurants/Taverns/Espresso $2.38 / sf $2.86 / sf (25%o rate reduction for schools without kitchens) SURFACE WATER/ STORM DRAINAGE Surface water capital fee - Eff l/l/l I Residential - $95/du Commercial - $95/3200sf of imp surface METER SERVICES Meter Size Tapping Fee Meter Drop Fee 518" x314" $ l,0s0 $500 314" x314" $ I,075 $52s t" $ I,200 $s60 1.5" $1,600 $7s0 2" $1,900 min $8s0 3".4".6".8" Time and Material - $3,500 min + $ltrVinch Included in tapping fee Fire sprinkler systems may require a Iarger meter for adequate fire flow - consult your designer. All commercial systems, fire systems, and irrigation systems require a double check valve assembly behind meter November 15, 2019 Eric Scott, P.E., Principal TerraVista NW, LLC 3204 Smokey Point Drive, Suite 207 Arlington, WA 98223 Subject: Infiltration Feasibility & Mounding Assessment Proposed Commercial Site Improvements â€“ Trailer Boss 16523 Smokey Point Blvd, Arlington, Washington MTC Project No.: 19B335 Dear Mr. Scott: At your request, Materials Testing & Consulting, Inc. (MTC) has completed a targeted site characterization for infiltration assessment at the above referenced site proposed for stormwater improvements along with the planned site development. MTC understands the client intends to develop the project site with a new 36x44-foot office, a 40x54-foot shop, and pave the majority of the interior of the site to provide parking areas and trailer storage. The project will install decentralized stormwater improvements to accompany the expanded site use. The client and design engineer have requested this infiltration study be performed in support of stormwater facility planning and final design. In addition, the designer has asked for calculation of groundwater mounding using simplified methods to determine minimum vertical separation guidelines for the facilities from shallow seasonal high groundwater. Preliminary discussions indicate stormwater infiltration will be done by multiple linear infiltration trenches or buried cells at locations to be determined spread throughout the site interior, if feasible conditions allow. Design of these features is pending confirmation of site suitability for infiltration and determination of design rates and minimum separation requirements by this study. MTC has performed this infiltration assessment in accordance with site characterization guidelines presented in the Washington Department of Ecology Stormwater Management Manual for Western Washington, 2012/2014 edition (SMMWW, 2012/2014) as adopted by the City of Arlington. A summary of MTCâ€™s field findings, laboratory results, interpretations, and recommendations pertaining to the proposed infiltration facilities including long-term design rates are provided herein. In addition, the results of Cation Exchange Capacity (CEC) and Organic Content (OC) analyses conducted on representative soil samples from the potential infiltration areas are attached at the end of this report for consideration in stormwater treatment if required. Environmental â— Geotechnical Engineering â— Special Inspecon â— Non-Destructive Testing â— Materials Tesng Burlington|Olympia|Bellingham|Silverdale|Tukwila 360.755.1990 www.mtc-inc.net Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Site Exploration and Assessment Methodology: On October 16, 2019, an MTC Project Geologist visited the site to observe and direct excavation of test pits for infiltration assessment and to collect soil samples for laboratory gradation analysis. MTC personnel observed excavation of test pits at six locations as determined on site by an MTC Geologist based on the proposed project layout, and space accessible for work at the time of the visit. The project site contains an existing business in a rectangular area (northwest portion) and will expand into a second rectangular area (southeast) oriented perpendicular to the first, with a small central area connecting them (see map). The northwestern portion of the site was generally inaccessible due to trailer staging and prevalent utilities, however MTC was provided a previous soils report from the site that included explorations in this area indicating similar conditions throughout the site. Test Pits TP-1 through TP-4 were excavated in the undeveloped southeastern part of the site. Locations were in the south-central, southeast, northeast, and northwest areas of the southeast lot, respectively. TP- 5 was sited in the south-central connecting area between the two lots. TP-6 was located in the south- central portion of the northwestern in-use lot. The previous soils report included two test pits in each of the two lots. An abandoned â€˜wet wellâ€™ was also observed on site just west of TP-6 where there had been a historically demolished residence. Explorations were field located by MTC and arranged for optimum coverage of potential areas for infiltration design. Backhoe test pits were completed to termination depths ranging from approximately 5.3 to 7.7 feet below present grade (BPG). Explorations were terminated upon sidewall caving due to groundwater inundation. Explorations were monitored by MTC personnel, who examined and classified the materials encountered in accordance with the Unified Soil Classification System (USCS) and ASTM D2487, obtained representative soil samples, and recorded pertinent information including soil stratigraphy, soil engineering characteristics, and indications of groundwater occurrences as well as visual evidence of seasonal groundwater. Upon completion, test pits were backfilled with soil tailings. Grab soil samples were collected from representative soil horizons during test pit excavation and at potential infiltration depths, as depicted on the attached logs. All samples were placed in plastic bags to limit moisture loss, labeled, and returned to MTCâ€™s laboratory for analysis and storage. Samples will be retained for a minimum of 90 days from the date of collection. A location and vicinity map are provided in Figure 1, Appendix A1. A site plan with approximate test locations is provided in Figure 2, Appendix A2. Attached in Appendix B are photos of the site and explorations in progress. Exploration logs are presented in Appendix C, with a USCS classification chart provided as Figure 3. Results of laboratory analyses on soil samples collected during the field visit are attached in Appendix D. 2 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Site Conditions: The project site is located in Arlington, Washington, east of the I-5 corridor on the east side of Smokey Point Boulevard, and roughly Â¼-mile south of SR 531. The property is located within a generally commercialized area, though it is neighbored to the south by a remaining single-family residence with a small yard. The west and north property boundaries are made up of Smokey Point Blvd and 166th Place NE, respectively. A moderately-sized power substation is located directly to the east and north, against the northwest and southeast areas respectively, and to the east of that is a preschool complex. The large site to the east of the southeast parcel is partially undeveloped. The site interior is approximately flat and is divided into two parcels in differing stages of development. Both areas have been cleared of all major vegetation. The northwest & central area contains chipped gravel throughout and is currently in use as a parking and staging area for Trailer Boss merchandise. Other minor structures observed in the northwest area include a small concrete parking pad to the northeast, a temporary office trailer to the east, an abandoned residential â€˜wet wellâ€™ in the southwest, and temporary lighting throughout the interior. The southeast area is generally undeveloped, though it has been graded, which apparently removed topsoil and the majority of organic material in preparation for the proposed development. Subsurface Soil Conditions: Subsurface soils were observed and catalogued during test pit excavations. This section summarizes our general understanding of site soil conditions gained from completing field explorations and laboratory analyses. We also reviewed prior report information provided by the client, as discussed below. The site exhibited various surface conditions including gravel over reworked native fill in the northwest area, and native alluvium exposed after topsoil stripping in the southeast. No topsoil was observed, though some organic material was seen in TP-5 and TP-6 within reworked fill materials. No obvious fill was observed in the southeastern area, indicating that grading to date has only included material removal. The upper undisturbed native soil profile beginning at the surface or by 1.25 to 1.5 feet BPG was composed of sand with silt to silty sand. Fines content within the upper unit was visually estimated to range from 10 to 15% and locally up to about 30%. Soils at TP-4 through TP-6 exhibited some local cohesion and blocky habit in the upper 1.5 to 3.0 feet, which correlated to a relatively higher fines content. A similar horizon, approximately 6 inches thick was observed at around 5.5 feet only in TP-6. Below the upper deposits, underlying material generally consisted of sand to sand with gravel & coarsening downward. The lower unit had minor to trace fines, and was moist to wet with depth. The upper boundary varied between test pits, though was generally at around 3 to 4 feet BPG. The outliers were at TP-1, where it was encountered at 2.2 feet, and at TP-6 where it was reached at 3.5 feet BPG. 3 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Previous work by others (Geotech Consultants, Inc.; 2016) was reviewed for general coverage and understanding of the full site conditions. The GCI report describes finding similar conditions of an upper silty sand and lower sand at all of four test pits. The interface between the units was also variable by location. Clean sand was contacted typically between 3 to 4 feet BPG, with soils above coarsening with depth. TP-1 was done in an area inaccessible during our field work, at the north-central part of the west lot. Their logging of silty sand to sand with silt to about 3.5 feet BPG corresponds closely with the closest MTC test pit (TP-6) further to the south. By comparison with the GCI results, we anticipate conditions to be widely similar throughout the site. Geologic Literature: The Geologic Map of the Arlington West 7.5 minute quadrangle, published by the US Geologic Survey depicts the site as within an area of Quaternary Recessional Outwash (Marysville Sand Member-Qvrm) based on 1:24,000-scale mapping. Qvrm deposits are associated with the meltwaters of the receding Vashon glacier. These deposits are typically described as stratified or massive, clean outwash sand with local areas of fine gravel, silt, and clay. In our experience, the uppermost deposits and cover soils of this unit are commonly composed of silty sand grading to coarse sand with depth. Shallow subsurface conditions at the site are mapped by the USDA NRCS Web Soil Survey as Custer Fine Sandy Loam (#13). Custer Fine Sandy Loam is described as deposited on outwash plains from a parent material of glacial outwash. Typical profile includes fine sandy loam to 9 inches, underlain by sand to past 60 inches. Where undrained, the soil is listed as poorly drained with a moderately high capacity to transmit water through its most limiting layer (upper conditions). Depth to the seasonal high- water table is listed at 0 to 12 inches. It is a member of Hydrologic Soil Group C/D. Native soil conditions encountered in the field (below surface fills, if present) are interpreted to consist of outwash sand deposits, ranging commonly from silty sand to sand with silt at upper levels with predominantly coarse-grained units beginning on average around 4 feet depth. Soils observed in field explorations generally correspond with mapped geology. Soils also broadly correspond with soil survey data, although the groundwater conditions documented by MTC and previous work differ from the described â€œundrainedâ€ conditions per the NRCS. Surface and Subsurface Water Conditions: The project site is roughly 0.4 miles northeast of Gissberg Twin Lakes, and roughly the same distance from small tributaries of Quilceda Creek to the south and east. The site is also approximately 3.2 miles south of the Stillaguamish River. No other major surface water features are present in the project area. 4 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 A prevalent groundwater table was encountered at the time of our field investigation in the fall season. All explorations also contained free water seepage at similar depths to the water table. After some open time for stabilization, groundwater was measured at around 5 feet depth in TP-1 and TP-2. Water levels were recorded between 6 to 7 feet depth in Test Pits TP-3 through TP-6 and within the nearby â€˜wet wellâ€™. Groundwater was most shallow in the southeast part of the site compared to surface grade, and relatively deeper to the west. This appears to be at least partly a function of relative surface grades between the two areas. Given the timeframe of the explorations in the early fall season following moderately high levels of precipitation (as well as precipitation during field work), conditions are expected to be seasonally elevated from base dry season levels, though not at fully developed wet season groundwater levels. Peak seasonal groundwater levels are normally established by mid-winter and persist through early spring. We observed for soil mottling and oxidation staining patterns to estimate seasonal high groundwater levels anticipated for the winter season. Shallow scattered mottling observed in the upper unit and along the top portion of the underlying sand is interpreted to be due to downward transmission of meteoric surface waters, and not a result of full seasonal saturation. Scattered mottling was observed throughout the upper deposits at all locations explored. No heavy linear feature, such as heavy oxidation banding, was seen that would strongly suggest a seasonal high water level. The absence of such evidence is not uncommon in predominantly coarse-grained soils. We did note the onset of low-chroma coloration within the lower sand unit before end depths suggesting groundwater inundation above the elevations observed. GCIâ€™s explorations were performed in late March of 2016, a year of notably higher rainfall. Their findings most likely reflect a stabilized high wet season level (not necessarily true peak but at least sustained). GCI recorded static groundwater levels of 3 to 5 feet BPG. Similar to our observations, the groundwater level was higher relative to surface grade at the southeast lot (4.0 and 3.0 feet BPG), and marginally deeper at the northwest lot (4.0 and 5.0 feet BPG). While MTC cannot certify the accuracy of the work by others, the recorded levels appear to correspond well with our observations of soil coloration. MTCâ€™s current scope of investigation did not include direct observation and determination of seasonal groundwater variations, or conclusive measurement of groundwater elevations by establishment of monitoring wells. The conditions on field logs are valid only for the date of exploration. Estimated seasonal high groundwater conditions based on indirect mottling evidence shall be understood as interpreted rather than a statement of fact. At the request of the client, MTC can perform additional site characterization involving the monitoring of seasonal groundwater elevations if required for final design and approval. 5 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Infiltration Assessment & Commentary: Gradation Analysis Method & Results During test pit excavations, MTC collected representative samples of soils among native strata at and below potential infiltration depths. No target depths or locations were set prior to field work. Based on project discussions, test pit observations, and the GCI work, we assume infiltration depths will be shallow and via linear infiltration trenches. MTC understands that the final locations, sizes, and depths of the infiltration facilities will be refined following the results of this study. Laboratory gradation analyses were completed via sieve tests for general rate determination to supplement field observations. Results of laboratory testing are summarized below. Laboratory results were interpreted to hydraulic conductivity (Ksat) values in accordance with methods of the Washington State Department of Ecology Stormwater Management Manual for Western Washington (SMMWW), 2012/2014. Standard correction factors were applied as noted in the reference documents. Data and Ksat values are summarized in Table 1. Gradation results were applied to the Massmann (2003) equation (1) to calculate Ksat representing the initial saturated hydraulic conductivity, as described in the 2012 DOE SMMWW Volume III 3.3.6.3. (1) log10(Ksat) = -1.57 + 1.90*D10 + 0.015*D60 - 0.013*D90 - 2.08*ff Table 2 reports for each sample the input laboratory values and calculated Ksat. Corrected Ksat values presented below are a product of the initial Ksat and correction factor CFT. For a generalized design situation, we have applied an average site variability factor of CFv = 0.5 along with typical values of CFt = 0.4 (for the Grain Size Method) and CFm = 0.9 (assuming standard influent control). (2) CFT = CFv x CFt x CFm = 0.5 x 0.4 x 0.9 = 0.18 Table 1. Results of Massmann Analysis Depth Ff Ksat Corrected Ksat TP # USCS D10 D60 D90 (BPG) (%) (inches/hour) (inches/hour) 2 2 SP-SM 0.12 0.578 1.785 6.9 44.81 8.07 2 5.5 SP 0.172 0.719 1.93 1.7 72.21 13.00 4 3 SP-SM 0.092 0.299 0.408 7.3 40.14 7.23 5 4 SP 0.152 0.358 1.372 1.5 67.08 12.07 6 2 SM 0.026 0.211 0.404 28.8 10.71 1.93 6 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Facility Design Discussion and Rates MTC understands the stormwater system will undergo further design pending the results of this assessment to confirm general feasibility of infiltration, design rates, and viable minimum separation to groundwater. Based on discussions with the designer, on-site stormwater management is anticipated to consist of a series of shallow, distributed linear infiltration trenches beneath or at the perimeter of paved areas. Locations and depths are to be determined. Grain size analysis methods based on SMMWW 2012/2014 standard calculation criteria yielded Corrected Ksat values for native alluvial soils in the upper 6 feet of the subsurface profile ranging from about 2 to 13 inches per hour. Rates should be divided into two sections for design purposes based on soil stratigraphy encountered. The upper silty sand to sand with silt (where tested) yielded Ksat values of as low as about 2 inches per hour (where fines content was elevated up to 25% to 30% maximum) and higher values of 7 to 8 inches per hour where fines contents were below 10%. These rates were derived from samples collected at 2 to 3 feet BPG. The sample from 2.0 feet BPG in TP-6 had a fines content approaching 30%, which is interpreted to be representative of the finer-grained end of the spectrum for the shallow unit where observed. For general site-wide application with locations and depths to be determined, we recommend applying a maximum design Ksat value of 2.0 inches/hour. Given the range of shallow conditions observed, actual infiltration rates are expected to be equal or better than this value at a given location. Use of a relatively low rate will also help to minimize potential for groundwater mounding. Rates derived from samples within the lower sand unit at depths of 4.0 and 5.5 feet BPG were in the realm of 12 to 13 inches per hour. While the transmission potential is greater with depth, the limiting factor of seasonal high groundwater may preclude placement of systems at that level. If specific design locations and dimensions are able to maintain minimum vertical separations as discussed below, a Ksat value of up to 10 inches/hour may be used for infiltration into the clean sand unit. For systems placed at greater depths, it is likely that wet season monitoring and explorations at final design locations will be required to closely dial in depths for final design and approval. The derived rates are meant to provide a general characterization of shallow subsurface transmission potential for the designerâ€™s use, but are not necessarily intended to be applied as a final infiltration rate for facilities of an undetermined location and depth or for systems of a larger size/volume than anticipated at this time. The inherent site limitation of depth to seasonal groundwater must be accounted for in design. We recommend the design rate be applied conservatively, and systems should maintain as much vertical separation as possible. The facility designer should also review assumed correction factors per reference literature to ensure applicability with the proposed development, level of anticipated 7 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 controls, and long-term maintenance plan. The designer may make reasonable adjustments to correction factors and resulting design values based on these criteria to ensure design and operational intent is met. The project may be eligible for an increase in design rate if Pilot Infiltration Testing (PIT) methods are conducted at design locations and depths, which are considered generally more reliable as a confirmation of actual field conditions and therefore can be applied less conservatively. The client can also elect to conduct additional sampling and rate analysis at actual facility locations for adjustment of sizing on a per-location basis. It is our opinion that grain size analysis methods should be suitable for general design use of the proposed systems at this site, in accordance with DoE SMMWW 2012/2014 requirements. The native soils are not considered to be compacted by prior development (aside from surface fills anticipated to be removed below facilities) or consolidated by glacial ice, and were observed to be relatively uniform with no significant cementation or local variations, except for those accounted for as discussed above. At request of the client, MTC can provide additional services for completing PITs or location-specific sampling to verify the final stormwater design. Treatment Suitability MTC subcontracted Cation Exchange Coefficient (CEC) and Organic Content (OC) testing of representative samples of the shallow native deposits considered for infiltration facilities. Soil samples yielded CEC values between 2.6 to 4.7 milliequivalents per 100 grams of soil (meq/100g). Organic content testing recorded between 1.6% and 3.4% organic matter by weight. Table 2 below shows the results from the laboratory testing. In our experience with similar soils, these values appear typical for the soil types encountered and their respective fines and organic contents observed. Table 2. Results of Cation Exchange Coefficient and Organic Content Analysis Depth Organic Content CEC TP # USCS (BPG) (% by weight) (meq/100g) 2 2.0 SP-SM 2.0 2.6 4 3.0 SP-SM 1.6 2.2 6 2.0 SM 3.4 4.7 The Department of Ecology 2012/2014 SMMWW, Volume III, Section 3.3.7 addresses minimum requirements for treatment soils under Site Suitability Criteria. According to SSC-6, native soils with CEC values of at least 5 meq/100g and >1% organic content by weight are considered suitable as treatment media without modification. The addition of soil amendments or the import of treatment- specific soil media may be used to achieve a higher CEC and produce a soil more suitable for treatment if required for design where native soils are deficient. In the case of this site, organic contents are above 8 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 target value (1% minimum) within the upper native soils. However, CEC values recorded are consistently in the range of about 2 to 4 meq/100g, below the minimum treatment threshold. CEC and OC tests were not completed on the lower sand unit. Based on our experience, clean sand soils typically do not meet the minimum standards for treatment without amendment. Therefore, if treatment is required as part of this design, soil amendment or treatment media will be necessary to meet treatment standards. Minimum depth for treatment-suitable soils is cited as 18 inches per the DoE SMMWW. If soils are amended or imported treatment media is installed, the LTIR of the facility must be adjusted accordingly by the designer if these modifications will negatively affect the infiltration rate cited above. Mounding Analysis Methods & Results: At request of the designer, MTC has completed a simplified mounding calculation employing the methods of Zomorodi (1991, 2005) for the anticipated stormwater infiltration system. The referenced method is applicable to relatively uniform soil and groundwater conditions, and use of small-scale linear features which have a length many times the width. In that case, the mound can be assessed in two dimensions, with the facility width being the governing factor along with underlying soil transmissivity (saturated Hydraulic Conductivity). The system is undergoing design at this time. Per project discussions, we anticipate the system will consist of decentralized trenches filled with gravel and supplied by a level perforated pipe or similar distribution system to control application over the infiltration area. From past experience, we assume a distribution pipe will be placed with its base at least 4 to 6 inches above the bottom of the gravel fill. In a practical sense, system failure may be considered as the point at which groundwater level meets the base of the pipe and impedes stormwater delivery. However, for the purposes of our analysis MTC considers maximum allowable mounding to be equal to the base of the gravel bed feature. Ksat Determination MTC performed the following mounding calculations using the simplified solutions for recharge strip mounding derived by Zomorodi (1991, 2005). The purpose was to verify minimum design vertical separation needed from seasonal high groundwater conditions for the anticipated style of facilities. Preparing for the calculations requires determining saturated hydraulic conductivities (Ksat) for representative soil conditions. Ksat values were adopted from the current study laboratory testing and gradation method calculations described above: Upper Unit Silty Sand, Sand With Silt (SM, SP-SM) Ksat = 21.4 feet/day Lower Unit Sand, low fines content (SP) Ksat = 134.2 feet/day 9 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Mounding Calculations In a simplified case, mounding potential for infiltrating water above a water table or restrictive horizon (h) is a function of recharge rate (i), horizontal Ksat (k), and recharge facility width (w) per equation (3): (3) h = (0.86 * i * w) / (k â€“ i) To address a maximum input scenario, the recharge rate (i) was set equal to the design infiltration rate per soil type (recommended values above). Conductivity (k) was applied using representative Ksat values listed above. Width of the facility was varied to determine a balance between practical vertical separation and likely optimal width for the anticipated system style. Mounding inputs and final results are tabulated in Table 3: TABLE 3. Summary of Mounding Analysis Results Hydraulic Soil Recharge Gravel Bed Maximum Mound Mound Height Conductivity Condition (i) Width (w) Central Height (Hc) at Edge (He) (Ksat = k) SM 21.4 4.0 5 0.99 0.64 SP 134.2 20.0 5 0.75 0.47 NOTE: All dimensions in feet. All rates in feet/day. Discussion of Results According to the results of this analysis, mounding will occur to some extent under the facility while stormwater infiltrates vertically and spreads laterally. In our experience with similar trench systems and shallow groundwater, a minimum separation of 1.0 feet can be viable if site soil conditions allow. In this case, the site conditions are generally well suited for infiltration. An optimum maximum width of 5.0 feet for trench features is recommended to minimize mounding potential to about 1 foot or less below the center of the trench. The mound also dissipates laterally from the center of the facility, with heights at the edges of the bed being reduced by over one-third. By about 10 feet from the facility center line, mounding effects on latent groundwater level are negligible. We also note, as discussed above, that shallow soils will typically be more transmissive than the most conservative value used for Ksat determination and mounding calculations. Therefore, actual mounding is anticipated to be less on average than what is noted in Table 3. By using the other Ksat values gained from shallow soil laboratory analysis and assuming a 5-foot trench width, we tabulate a lower mound height of about 0.3 feet. 10 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Closing Remarks: MTC recommends that we be contacted to review proposed stormwater facility design, site preparation plans, and project specifications, to ensure they are consistent with the intent of the recommendations provided herein. In addition, MTC recommends that we be contacted for construction phase testing, observation, and engineering consultation services as may be needed. Such services may include but are not limited to earthwork support consulting, subgrade bearing and infiltration verifications, laboratory materials analysis, and special inspections if required. Mr. Scott, we trust this report presents the information you require. If you have questions, please do not hesitate to call. Respectfully Submitted; 11-15-2019 John R. Gillaspy, L.E.G. Mike Furman, G.I.T. NW Region Geotechnical Division Manager Project Geologist Attached: Limitations and Use of this Report Appendix A1. Location and Vicinity Map Appendix A2. Site Plan with Test Locations Appendix B. Photos of Site Exploration Appendix C. Exploration Logs Appendix D. Laboratory Results 11 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Limitations and Use of This Report Recommendations contained in this report are based on our understanding of the proposed development and construction activities, our field observations and explorations, and our laboratory test results. It is possible that soil and groundwater conditions could vary and differ between or beyond the points explored. If soil or groundwater conditions are encountered during construction that vary or differ from those described herein, we should be notified immediately in order to review and provide supplemental recommendations. If the scope of the proposed construction, including the proposed loads or structural locations, changes from that described in this report, we should be notified to review and provide supplemental recommendations. We have prepared this report in substantial accordance with the generally accepted geotechnical engineering practice as it exists in the site area at the time of our study. No warranty, expressed or implied, is made. The recommendations provided in this report assume that an adequate program of tests and observations will be conducted by MTC during the construction phase in order to evaluate compliance with our recommendations. This report may be used only by the Client and their design consultants and only for the purposes stated within a reasonable time from its issuance, but in no event later than 18 months from the date of the report. It is the Client's responsibility to ensure that the Designer, Contractor, Subcontractors, etc. are made aware of this report in its entirety. Note that if another firm assumes Geotechnical Engineer of Record responsibilities, they need to review this report and either concur with the findings, conclusions, and recommendations or provide alternate findings, conclusions and recommendation under the guidance of a professional engineer registered in the State of Washington. Land or facility use, on- and off-site conditions, regulations, or other factors may change over time, and additional work may be required. Based on the intended use of the report, MTC may recommend that additional work be performed and that an updated report be issued. Non-compliance with any of these requirements by the Client or anyone else will release MTC from any liability resulting from the use of this report. The Client, the design consultants, and any unauthorized party, agree to defend, indemnify, and hold harmless MTC from any claim or liability associated with such unauthorized use or non- compliance. We recommend that MTC be given the opportunity to review the final project plans and specifications to evaluate if our recommendations have been properly interpreted. We assume no responsibility for misinterpretation of our recommendations. The scope of work for this subsurface exploration and geotechnical report did not include environmental assessments or evaluations regarding the presence or absence of wetlands or hazardous substances in the soil, surface water, or groundwater at this site. 12 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix A1. Location and Vicinity Map Site Vicinity Site Location Maps Source: Google Imagery 2019 Materials Testing & Consulting, Site Location & Vicinity FIGURE Inc. Trailer Boss Infiltration Study 777 Chrysler Drive 16523 Smokey Point Blvd 1 Burlington, WA 98233 Arlington, WA 13 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix A2. Site Plan with Test Locations 1 2 TP-4 TP-3 3 TP-6 TP-5 4 TP-2 0 90 MTC 2019 Test Pit Location (approximate) TP-1 Previous Explorations (GCI, 3-24-2016) SCALE (FEET) 1 inch ~ 90 feet Materials Testing & Consulting, Inc. Base Map: Paving Plan â€“ Trailer Boss Site Site Plan with Test Locations FIGURE By: TerraVista NW 8-5-2019 777 Chrysler Drive Trailer Boss Infiltration Study Overlay by MTC: 10-29-2019 2 Burlington, WA 98233 NOT INTENDED FOR CONSTRUCTION 16523 Smokey Point Blvd NOT TO SCALE - Shown is Approximate Arlington, WA 14 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix B. Photos of Site Exploration TP-1 Photo A: Overview of northwestern portion of project site, looking north from the south-central end of proposed improvement area. Note prevalent impediments among middle and north end. Photo B: Overview of southeastern portion of project site, looking southeast from the central transition area of property. No vegetation remains. 15 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 TP-1 Photo C: TP-1 excavation in southeast area. Soil is generally sandy but coarsens with depth. Note mottling in upper subsurface that fades at around 3 feet depth. Groundwater at 5.0 feet BPG. TP-6 Photo D: TP-6 excavation in southwest area of project site. Organic material and disturbed soils observed below imported chipped surfacing to 1.5 feet BPG. Shallow native soils were silty sand, with mottling throughout. Gray sand below about 3.5 feet BPG. Groundwater at 7.0 feet BPG. 16 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix C. Exploration Logs UNIFIED SOIL CLASSIFICATION SYSTEM - USCS LOG SYMBOLS MAJOR DIVISIONS USCS SYMBOL TYPICAL DESCRIPTIONS SAMPLES GW WELL-GRADED GRAVEL SPT Standard Penetration Test < 5% FINES GRAVEL CLEAN GRAVEL Grab or bulk WITH LESS THAN POORLY-GRADED GRAVEL Gravel > Sand 5% FINES GP California or D&M (3.0" OD) < 5% FINES (More than half Shelby Tube of coarse fraction SILTY GRAVEL is larger than GM COARSE GRAVEL > 12% FINES (SILT > CLAY) #4 sieve) GRAINED WITH OVER WATER TABLE SOILS 12% FINES CLAYEY GRAVEL GC Groundwater Level > 12% FINES (CLAY > SILT) (where first encountered) More than half of Groundwater Level material is larger WELL-GRADED SAND CLEAN SAND SW (measured after completion) than the #200 < 5% FINES WITH LESS THAN Perched Groundwater Level sieve SAND 5% FINES (during exploration) SP POORLY-GRADED SAND Silt and / or Clay < 5% FINES Sand > Gravel content as (More than half specified SILTY SAND of coarse fraction SM > 12% FINES (SILT > CLAY) DENSITY: COARSE-GRAINED SOIL is smaller than SAND WITH the #4 sieve) OVER 12% FINES APPARENT SPT SC CLAYEY SAND DENSITY Blows / foot > 12% FINES (CLAY > SILT) Very Loose < 5 INORGANIC SILT; LEAN, LOW PLASTICITY Loose 5 - 10 ML SILT. Medium Dense 11 - 30 Dense 31 - 50 SILT AND CLAY INORGANIC CLAY; LEAN, LOW PLASTICITY Very Dense > 50 FINE CL GRAINED Lean, low to medium plasticity CLAY SOILS (Liquid limit less than 50) ORGANIC SILT & ORGANIC CLAY, OL LEAN, LOW PLASTICITY, DENSITY: FINE-GRAINED SOIL RETAINS VERY HIGH MOISTURE More than half of material is fines INORGANIC SILT, HIGH PLASTICITY, APPARENT SPT (smaller than the MH DENSITY Blows / foot FAT SILT, MAY BE MICACEOUS #200 sieve) SILT AND CLAY Very Soft < 3 CH INORGANIC CLAY, HIGH PLASTICITY, Soft 3 - 4 Sand and / or FAT CLAY Fat, high plasticity Medium Stiff 5 - 8 Gravel content as specified in log (Liquid limit greater than 50) ORGANIC CLAY & ORGANIC SILT Stiff 9 - 15 OH FAT, HIGH PLASTICITY, Very Stiff 16 - 30 RETAINS VERY HIGH MOISTURE Hard > 30 PEAT, HUMUS, SWAMP SOILS, HIGHLY ORGANIC SOILS PT PREDOMINANTLY ORGANIC CONTENT NOTES STRATIGRAPHIC CONTACT USCS evaluated by field observations. Laboratory analyses used when conducted. (approximated by field identification) Poorly-Graded (GP or SP) indicate not an equal content of every grain size subgroup. Distinct stratigraphic Calculated using 10%, 30%, and 60% grain size. contact between soil strata Combination names (e.g. SP-SM Poorly-Graded SAND with silt, represent fines Gradual change between soil strata content between 5% and 12%. Fines content is dominantly either clay (c) or silt (m). Approximate location of A soil description of "with sand" or "with gravel" represents greater than 15% coarse stratigraphic change material, and dominant coarse soil is the one specified. DEFINITIONS OF SOIL FRACTIONS MODIFIERS (see USCS and Notes) SOIL COMPONENT GRAIN SIZE (inch) GRAIN SIZE (metric) DESCRIPTION % Boulder > 12 in. > 305 mm Trace Cobbles 3 in. to 12 in. 75 mm to 305 mm <5% Gravel 3 in. to # 4 sieve 75 mm to 4.75 mm With Clay, With Silt 5 - 12% Fines Coarse Gravel 3 in. to 3/4 in. 75 mm to 19 mm Clayey, Silty >12% Fines Fine Gravel 3/4 in. to # 4 19 mm to 4.75 mm With Sand, With Gravel 15 - 30% Coarse Sand # 4 to # 200 4.75 mm to 0.075 mm Sandy, Gravelly >30% Coarse Coarse # 4 to # 10 4.75 mm to 2 mm Medium # 10 to # 40 2 mm to 0.425 mm Fine # 40 to #200 0.425 mm to 0.075 mm C o p y r ig h t 2 0 1 9 M T C I n c . 3 / 4 / 2 0 1 9 Fines (Silt or Clay) < #200 sieve < 0.075 mm Materials Testing & Consulting, Inc. Exploration Log Key FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 3 Arlington, WA 17 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-1 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : S Center of East lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 SAND WITH SILT to SILTY SAND, trace gravel up to 1/4", fine & medium-grained sand, moist, loose to medium dense, contains moderate organics including 1/2" roots. Light BROWN to TAN-GRAY with light to moderate mottling throughout. 1 SP-SM Local heavy mottling at ~1.6'. 2 SAND WITH GRAVEL, trace silt, moist, loose to medium dense, minor organics including 0.25" roots, gravel up to 1/2" with medium & coarse-grained sand. Medium GRAY. 3 SP 4 Increase in gravel content observed at 4' BPG. 5 Heavy seepage observed at 5' BPG. T.D. @ ~5.3' due to sidewall caving Stabilized water level observed at 5.0' BPG. 6 7 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-1.bor 18 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-2 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : SE corner of E lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 SAND WITH SILT, some gravel up to 1/4", fine & medium-grained sand, moist, loose to medium dense, contains moderate organics including 1/2" roots. Light BROWN to TAN-GRAY with light to moderate mottling throughout, local heavy oxidation staining. 1 SP-SM 2 CEC: 2.6 meq/100 OC: 2% 6.9% 9.1% 3 SAND WITH GRAVEL, trace SILT, gravel up to 1/2", medium & coarse-grained sand, moist, loose to medium dense, contains trace organics and 1/2" roots. Medium GRAY. Increase in gravel content observed at 3.5' BPG. 4 Becomes wet at 4.0' BPG. SP Seepage observed at 4.8' BPG. 5 1.7% 25.9% 6 T.D. @ ~6.2' due to sidewall caving Stabilized water level observed at 5.0' BPG. 7 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-2.bor 19 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-3 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : NE area of E lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 SAND WITH SILT AND GRAVEL, gravel up to 1/4", moist, loose to medium dense, contains moderate organics and 1/2" roots. Light BROWN to TAN-GRAY with light to moderate mottling throughout. 1 Local heavy mottling at ~1.0'. Sand observed to coarsen with depth. 2 SP-SM 3 4 SAND WITH GRAVEL, trace silt, moist to wet with depth, loose to medium dense, minor organics including 1/2" roots, gravel up to 1/2" with medium & coarse-grained sand. Medium GRAY. 5 SP Increase in gravel content observed at 5.5' BPG. Becomes wet at 5.5' BPG. 6 Heavy seepage observed at 6.0' BPG. 7 T.D. @ ~7.0' due to sidewall caving Stabilized water level observed at 5.8' BPG. 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-3.bor 20 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-4 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : NW/Ctr of E lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 SAND WITH SILT to SILTY SAND, trace gravel up to 1/4", fine & medium-grained sand, moist, loose to medium dense, contains moderate organics including 1/2" roots. Light BROWN to TAN-GRAY with moderate mottling becoming lighter with depth. 1 Excavated soils exhibit some cohesion and blocky habit at 1.5' BPG. SP-SM 2 3 CEC: 2.2 meq/100 OC: 1.6% 7.3% 8.0% SAND WITH GRAVEL, trace silt, moist to wet with depth, loose to medium dense, minor 4 organics including 1/2" roots, gravel up to 1" with medium & coarse-grained sand. Medium GRAY with faint mottling. 5 SP 6 Becomes wet at 6.7' BPG. 7 Seepage observed at 7.0' BPG. SP-SM SAND WITH SILT to SILTY SAND, fine-grained sand, wet, medium dense, exhibits some cohesion and blocky habit when excavated. Medium GRAY. 8 T.D. @ ~7.7' due to sidewall caving Stabilized water level observed at 7.0' BPG. 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-4.bor 21 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-5 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : South Central transition area (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 GW Chipped GRAVEL Imported Surfacing Material SAND WITH SILT, moist, loose, contains organics including carbonized wood and roots up to 1/2" thick. Light BROWN to dark REDDISH BROWN, variable. SP-SM Apparent reworked native fill 1 SILTY SAND, some gravel, moist, loose to medium dense, contains moderate organics including some 1/2" roots. Light BROWN to TAN-GRAY with moderate mottling becoming lighter with depth. 2 Excavated soils exhibit some cohesion and blocky habit at 2.0' BPG. SM 3 SAND WITH GRAVEL, trace silt, moist to wet with depth, medium dense, minor organics 4 including 1/2" roots, gravel up to 1" with medium & coarse-grained sand. Medium GRAY with faint mottling. 1.5% 30.7% 5 Gravel content observed to increase with depth. SP 6 Seepage observed at 6.5' BPG. 7 T.D. @ ~7.5' due to sidewall caving Stabilized water level observed at 6.5' BPG. 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-5.bor 22 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-6 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : South Central part of W lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 GW Chipped GRAVEL, Imported Surfacing Material SAND WITH SILT, moist, loose, contains organics including carbonized wood and roots up to 1/2" thick. Light BROWN to dark REDDISH BROWN, variable. SP-SM Apparent reworked native fill 1 SILTY SAND, some gravel, moist, loose to medium dense, contains moderate organics including some 1/2" roots. Light BROWN to TAN-GRAY with moderate mottling becoming lighter with depth. 2 CEC: 4.7 meq/100 OC:3.4% 28.8% 25.9% SM 3 Excavated soils exhibit some cohesion and blocky habit at 3.0' BPG. SAND, trace gravel and silt, moist to wet with depth, medium dense, minor organics including 1/2" roots, gravel up to 1" with medium & coarse-grained sand. Medium GRAY with faint mottling. 4 SP 5 SILTY SAND, fine-grained sand, wet, medium dense, blocky habit. Medium GRAY. 25.1% SM SAND, trace gravel and silt, wet, medium dense, minor organics including 1/2" roots, gravel up to 1" with medium & coarse-grained sand. Medium GRAY with faint mottling. 6 SP Seepage observed between 6.5 & 7.0' BPG. 7 T.D. @ ~7.5' due to sidewall caving Stabilized water level observed at 7.0' BPG. 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-6.bor 23 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix D. Laboratory Results Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SP-SM, Poorly graded Sand with Silt Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-2 @ 2.0' Tested By: A. Eifrig brown Sample#: B19-1012 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.054 mm % Gravel = 3.5% Coeff. of Curvature, CC = 0.99 Specifications D(10) = 0.120 mm % Sand = 89.6% Coeff. of Uniformity, CU = 4.80 No Specs D(15) = 0.169 mm % Silt & Clay = 6.9% Fineness Modulus = 2.27 Sample Meets Specs ? N/A D(30) = 0.262 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.386 mm Plasticity Index = n/a Moisture %, as sampled = 9.1% D(60) = 0.578 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 1.785 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 9/73 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 100% 100.0% 0.0% 1.50" 37.50 100% 100.0% 0.0% 1.25" 31.50 100% 100.0% 0.0% 60% 60.0% 1.00" 25.00 100% 100.0% 0.0% 3/4" 19.00 100% 100% 100.0% 0.0% 5/8" 16.00 99% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 98% 98% 100.0% 0.0% 3/8" 9.50 98% 98% 100.0% 0.0% 40% 40.0% 1/4" 6.30 97% 100.0% 0.0% #4 4.75 97% 97% 100.0% 0.0% #8 2.36 95% 100.0% 0.0% 30% 30.0% #10 2.00 95% 95% 100.0% 0.0% #16 1.18 75% 100.0% 0.0% #20 0.850 67% 100.0% 0.0% 20% 20.0% #30 0.600 61% 100.0% 0.0% #40 0.425 56% 56% 100.0% 0.0% 10% 10.0% #50 0.300 36% 100.0% 0.0% #60 0.250 28% 100.0% 0.0% #80 0.180 17% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 12% 12% 100.0% 0.0% #140 0.106 9% 100.0% 0.0% Particle Size (mm) #170 0.090 8% 100.0% 0.0% #200 0.075 6.9% 6.9% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-2 @ 2.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 4a Arlington, WA 24 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Materials Testing & Consulting, Inc. Lab Sample: TP-2 @ 2.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 4b Arlington, WA 25 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SP, Poorly graded Sand Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-2 @ 5.5' Tested By: A. Eifrig brown Sample#: B19-1013 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.128 mm % Gravel = 5.4% Coeff. of Curvature, CC = 0.68 Specifications D(10) = 0.172 mm % Sand = 92.9% Coeff. of Uniformity, CU = 4.19 No Specs D(15) = 0.201 mm % Silt & Clay = 1.7% Fineness Modulus = 2.53 Sample Meets Specs ? N/A D(30) = 0.290 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.409 mm Plasticity Index = n/a Moisture %, as sampled = 25.9% D(60) = 0.719 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 1.930 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 2/63 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 99% 100.0% 0.0% 1.50" 37.50 99% 100.0% 0.0% 1.25" 31.50 98% 100.0% 0.0% 60% 60.0% 1.00" 25.00 97% 97% 100.0% 0.0% 3/4" 19.00 97% 97% 100.0% 0.0% 5/8" 16.00 97% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 97% 97% 100.0% 0.0% 3/8" 9.50 96% 96% 100.0% 0.0% 40% 40.0% 1/4" 6.30 95% 100.0% 0.0% #4 4.75 95% 95% 100.0% 0.0% #8 2.36 92% 100.0% 0.0% 30% 30.0% #10 2.00 92% 92% 100.0% 0.0% #16 1.18 71% 100.0% 0.0% #20 0.850 63% 100.0% 0.0% 20% 20.0% #30 0.600 57% 100.0% 0.0% #40 0.425 53% 53% 100.0% 0.0% 10% 10.0% #50 0.300 32% 100.0% 0.0% #60 0.250 23% 100.0% 0.0% #80 0.180 11% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 6% 6% 100.0% 0.0% #140 0.106 4% 100.0% 0.0% Particle Size (mm) #170 0.090 3% 100.0% 0.0% #200 0.075 1.7% 1.7% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-2 @ 5.5â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 5 Arlington, WA 26 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SP-SM, Poorly graded Sand with Silt Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-4 @ 3.0' Tested By: A. Eifrig brown Sample#: B19-1014 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.051 mm % Gravel = 0.0% Coeff. of Curvature, CC = 1.30 Specifications D(10) = 0.092 mm % Sand = 92.7% Coeff. of Uniformity, CU = 3.25 No Specs D(15) = 0.123 mm % Silt & Clay = 7.3% Fineness Modulus = 1.28 Sample Meets Specs ? N/A D(30) = 0.189 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.262 mm Plasticity Index = n/a Moisture %, as sampled = 8.0% D(60) = 0.299 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 0.408 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 1/13 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 100% 100.0% 0.0% 1.50" 37.50 100% 100.0% 0.0% 1.25" 31.50 100% 100.0% 0.0% 60% 60.0% 1.00" 25.00 100% 100.0% 0.0% 3/4" 19.00 100% 100.0% 0.0% 5/8" 16.00 100% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 100% 100% 100.0% 0.0% 3/8" 9.50 100% 100% 100.0% 0.0% 40% 40.0% 1/4" 6.30 100% 100.0% 0.0% #4 4.75 100% 100% 100.0% 0.0% #8 2.36 100% 100.0% 0.0% 30% 30.0% #10 2.00 100% 100% 100.0% 0.0% #16 1.18 97% 100.0% 0.0% #20 0.850 96% 100.0% 0.0% 20% 20.0% #30 0.600 95% 100.0% 0.0% #40 0.425 95% 95% 100.0% 0.0% 10% 10.0% #50 0.300 60% 100.0% 0.0% #60 0.250 47% 100.0% 0.0% #80 0.180 28% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 19% 19% 100.0% 0.0% #140 0.106 12% 100.0% 0.0% Particle Size (mm) #170 0.090 10% 100.0% 0.0% #200 0.075 7.3% 7.3% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-4 @ 3.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 6a Arlington, WA 27 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Materials Testing & Consulting, Inc. Lab Sample: TP-4 @ 3.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 6b Arlington, WA 28 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SP, Poorly graded Sand Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-5 @ 4.0' Tested By: A. Eifrig brown Sample#: B19-1015 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.108 mm % Gravel = 0.2% Coeff. of Curvature, CC = 1.01 Specifications D(10) = 0.152 mm % Sand = 98.3% Coeff. of Uniformity, CU = 2.35 No Specs D(15) = 0.173 mm % Silt & Clay = 1.5% Fineness Modulus = 1.80 Sample Meets Specs ? N/A D(30) = 0.234 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.317 mm Plasticity Index = n/a Moisture %, as sampled = 30.7% D(60) = 0.358 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 1.372 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 1/50 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 100% 100.0% 0.0% 1.50" 37.50 100% 100.0% 0.0% 1.25" 31.50 100% 100.0% 0.0% 60% 60.0% 1.00" 25.00 100% 100.0% 0.0% 3/4" 19.00 100% 100.0% 0.0% 5/8" 16.00 100% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 100% 100% 100.0% 0.0% 3/8" 9.50 100% 100% 100.0% 0.0% 40% 40.0% 1/4" 6.30 100% 100.0% 0.0% #4 4.75 100% 100% 100.0% 0.0% #8 2.36 99% 100.0% 0.0% 30% 30.0% #10 2.00 99% 99% 100.0% 0.0% #16 1.18 87% 100.0% 0.0% #20 0.850 82% 100.0% 0.0% 20% 20.0% #30 0.600 79% 100.0% 0.0% #40 0.425 76% 76% 100.0% 0.0% 10% 10.0% #50 0.300 46% 100.0% 0.0% #60 0.250 34% 100.0% 0.0% #80 0.180 17% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 9% 9% 100.0% 0.0% #140 0.106 5% 100.0% 0.0% Particle Size (mm) #170 0.090 3% 100.0% 0.0% #200 0.075 1.5% 1.5% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-5 @ 4.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 7 Arlington, WA 29 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SM, Silty Sand Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-6 @ 2.0' Tested By: A. Eifrig brown Sample#: B19-1016 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.013 mm % Gravel = 0.4% Coeff. of Curvature, CC = 1.14 Specifications D(10) = 0.026 mm % Sand = 70.7% Coeff. of Uniformity, CU = 8.09 No Specs D(15) = 0.039 mm % Silt & Clay = 28.8% Fineness Modulus = 0.86 Sample Meets Specs ? N/A D(30) = 0.079 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.148 mm Plasticity Index = n/a Moisture %, as sampled = 25.9% D(60) = 0.211 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 0.404 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 30/97 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 100% 100.0% 0.0% 1.50" 37.50 100% 100.0% 0.0% 1.25" 31.50 100% 100.0% 0.0% 60% 60.0% 1.00" 25.00 100% 100.0% 0.0% 3/4" 19.00 100% 100.0% 0.0% 5/8" 16.00 100% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 100% 100% 100.0% 0.0% 3/8" 9.50 100% 100% 100.0% 0.0% 40% 40.0% 1/4" 6.30 100% 100.0% 0.0% #4 4.75 100% 100% 100.0% 0.0% #8 2.36 99% 100.0% 0.0% 30% 30.0% #10 2.00 99% 99% 100.0% 0.0% #16 1.18 96% 100.0% 0.0% #20 0.850 95% 100.0% 0.0% 20% 20.0% #30 0.600 94% 100.0% 0.0% #40 0.425 93% 93% 100.0% 0.0% 10% 10.0% #50 0.300 74% 100.0% 0.0% #60 0.250 66% 100.0% 0.0% #80 0.180 55% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 51% 51% 100.0% 0.0% #140 0.106 38% 100.0% 0.0% Particle Size (mm) #170 0.090 33% 100.0% 0.0% #200 0.075 28.8% 28.8% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-6 @ 2.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 8a Arlington, WA 30 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Materials Testing & Consulting, Inc. Lab Sample: TP-6 @ 2.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 8b Arlington, WA 31 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Materials Testing & Consulting, Inc. Geotechnical Engineering â€¢ Special Inspection â€¢ Materials Testing â€¢ Environmental Consulting Project: Trailer Boss Infiltration & Mounding Study Client: Terra Vista NW, LLC Project #: 19B335 Date Received: October 22, 2019 Sampled by: M. Furman Date Tested: October 23, 2019 Tested by: A. Eifrig Amount of Materials Finer Than #200 Sieve - ASTM C-117, ASTM D-1140 & AASHTO T-11 Sample # Location Tare Before Wash + Tare After Wash + Tare Amount of Loss % -#200 B19-1017 TP-6 @ 5.2' 731.4 1743.9 1489.5 254.4 25.1% 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! All results apply only to actual locatio ns and materials tested. As a mutual protectio n to clients, the public and ourselves, all reports are submitted as the confidential p rop erty of clients, and authorization for publication of statements, conclusions or extracts from or regarding our rep orts is reserved pending our written approval. Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-6 @ 5.2â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 9 Arlington, WA 32 NW 28 T31N R 5E LLC SITE Consulting Engineers TerraVista NW GENERAL INFORMATION TRAILER BOSS C1.1 Plotted: Dec 17, 2019 - 11:06am Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C1.1 GEN INFO NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW â€œ â€ GENERAL NOTES TRAILER BOSS C1.2 Plotted: Dec 17, 2019 - 11:06am Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C1.2-GEN NOTES NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW â€™ SWPPP NOTES TRAILER BOSS C1.3 Plotted: Dec 17, 2019 - 11:06am Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C1.3-SWPPP NOTES NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW 0 30 60 SWPPP TRAILER BOSS Scale in Feet C2.1 Plotted: Dec 17, 2019 - 11:07am Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C2.1-SWPPP NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW 0 30 60 Scale in Feet PAVING PLAN TRAILER BOSS C2.2 Plotted: Dec 17, 2019 - 11:07am Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C2.2 PAVING PLAN NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW 0 30 60 Scale in Feet GRADING PLAN TRAILER BOSS C2.3 Plotted: Dec 17, 2019 - 11:07am Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C2.3-GRAD PLAN NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW 0 30 60 Scale in Feet DRAINAGE PLAN TRAILER BOSS C2.4 Plotted: Dec 17, 2019 - 11:07am Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C2.4-SD PLAN NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW SWPPP DETAILS TRAILER BOSS C3.1 Plotted: Dec 17, 2019 - 11:07am Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C3.1-SWPPP DETAILS NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW PAVING DETAILS TRAILER BOSS C3.2 Plotted: Dec 17, 2019 - 11:07am Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C3.2-PAVE DETAILS NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW STORM DRAINAGE DETAILS TRAILER BOSS C3.4 Plotted: Dec 17, 2019 - 11:07am Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C3.4-SD DET NW 28 T31N R 5E 0 20 40 Scale in Feet LLC Consulting Engineers TerraVista NW LANDSCAPE PLAN TRAILER BOSS L1.1 Plotted: Dec 17, 2019 - 11:07am Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: L1.1-LANDSCAPE COMPLETE STREETS CHECKLIST Community & Economic Development City of Arlington â€¢ 18204 59th Avenue NE â€¢ Arlington, WA 98223 â€¢ Phone (360) 403-3551 Project Name: Email: Project Manager/Owner: Phone No.: Description of Scope: Roadway Classification: ï² Principal ï² Minor ï² Collector ï² Non-Arterial ï² Boulevard ï² Alley Cross Connection Type: ï² Downtown ï² Urban Center Connector ï² Neighborhood Yield ï² Downtown Neighborhood ï² Industrial Access ï² Mixed Use Overlay ï² Urban Village Main ï² Neighborhood Corridor ï² Smokey Point Corridor ï² Urban Village Neighborhood ï² Neighborhood Curbless Page 1 of 7 Revised 8/18 1. CHANNELIZATION Average Daily Trips: Should re-channelization Contact Public Works 360-403-3512 be considered in the project scope? Speed Limit: Current image or typical existing cross-section of street in project area (showing lane configuration): 2. PAVEMENT CONDITIONS Does the existing road maintain the minimum Overall Condition Index (OCI) as set ï² Yes ï² No forth in the Transportation Benefit District? Contact Public Works for current OCI and Standards 360-403-3512. Has the installation of traffic circles been considered? ï² Yes ï² No Is this project on the cityâ€™s Transportation Improvement Plan? ï² Yes ï² No Should pavement repair be considered through this project? ï² Yes ï² No If yes, please explain. 3. PEDESTRIAN INFRASTRUCTURE Is this area identified in the City of Arlington Pedestrian Improvement Plan? If so, ï² Yes ï² No have the recommendations been met? Explain how or why not. People walking or using a mobility device: Is the project fully served by sidewalks, ï² Yes ï² No accessible curb ramps, and safe crosswalks? If not, are new/repaired sidewalks, curb ramps, and crosswalks included in the project? Page 2 of 7 Revised 8/18 Explain how or why not. Are existing sidewalk in good condition? ï² Yes ï² No Has an initial assessment of trees and sidewalk conditions been conducted with ï² Yes ï² No and engineer and arborist/landscape architect? Are there missing sidewalk in the project area? ï² Yes ï² No If yes, explain how this will be corrected? Crossing Width (number of lanes) _______________ Controlled Stop Spacing ______________________________ Does the project propose mid-block crossings to reduce distance between ï² Yes ï² No crossings? Is there pedestrian refuge or flashing beacons in the project area? ï² Yes ï² No Explain pedestrian existing crossing convenience, visibility and safety; does the project target improvements to accessibility? Have the addition of curb bulb outs been considered to slow traffic and reduce ï² Yes ï² No crossing width? Describe how the building(s) have been oriented to address the adjacent roadway with visible connected sidewalks that encourage and enhance pedestrian circulation. Describe pedestrian facilities added such as benches, trash receptacles, visual interest, shade and plantings. Page 3 of 7 Revised 8/18 4. BICYCLE INFRASTRUCTURE Is this area identified in the City of Arlington Bicycle Improvement Plan? ï² Yes ï² No If so, have the recommendations been met? Explain how or why not. Is the project site fully served by bicycle facilities? If not, are new bicycle facilities ï² Yes ï² No included in the project? Explain how or why not. Does this project meet the needs of a variety of bicycle users? ï² Yes ï² No (Family vs. Commuter) How? Describe how the building(s) serve and invite bicycle traffic, e.g. covered bike racks, visual interest, smooth transitions, bicycle focused travel ways. 5. TRANSIT INFRASTRUCTURE Transit Classification: ï² Major Transit Route ï² Minor Transit Route Is the project identified on the City of Arlington Transit Expansion Plan? ï² Yes ï² No ï‚· Are there bus stops on the project area? ï² Yes ï² No ï‚· Are all bus stops in the project area within close proximity to a controlled ï² Yes ï² No crossing? ï‚· Average distance between bus stops in/adjacent to project area? ï‚· If bus stops are less than 0.2 miles (1056 ft.) apart, can stops be consolidated? Explain: Page 4 of 7 Revised 8/18 Does the stop provide cover and seating? ï² Yes ï² No How or why not. Does the project add visual interest, shading, lighting, plantings, or traffic buffers? ï² Yes ï² No Explain how the project improves transit usersâ€™ comfort and convenience. Is the transit stop ADA accessible? If not, how does the project propose to provide ï² Yes ï² No accessibility? How or why not. 6. FREIGHT INFRASTRUCTURE Is the project on an identified City of Arlington Freight Route? ï² Yes ï² No Does the project area meet the curb radius and clearance standards? ï² Yes ï² No Are there spot improvements needed for the project area? (pavement depth) ï² Yes ï² No 7. STREET TREES AND LANDSCAPING Describe any existing street trees and landscaping assets within the project limits that warrant project investment to sustain (e.g. preservation of street trees): Is there an opportunity to plant trees or expand landscape? ï² Yes ï² No Page 5 of 7 Revised 8/18 Will there be long-term street tree and landscaping maintenance required for this ï² Yes ï² No project? How will the maintenance of plants be addressed? Are street median planting proposed in the project area? ï² Yes ï² No Does the project include any environmental elements? E.g.: street trees, reduced ï² Yes ï² No pavement, bio-infiltration, vegetated bump outs, native/drought tolerant vegetation, or other environmental improvements to be implemented with the project? Explain how or why not. 8. URBAN DESIGN AND PLANNING If an adopted subarea or action plan applies to this project, has its ï² Yes ï² No recommendations relevant to improved streets/ROW been met? Explain how or why not. Has connectivity been improved for all modes of travel? ï² Yes ï² No Explain specifically for each mode of travel. Is there an opportunity to implement artistic elements (e.g. sidewalk inlays, ï² Yes ï² No creative street furniture, or bollards or planters, creative bicycle racks etc.) in the project area? Explain how. Page 6 of 7 Revised 8/18 Describe Public Art or Art Opportunities: ï² Yes ï² No Arlington Art Council may be a resource 360-435-3778 or arlingtonartscouncil.net CITY USE ONLY Approval Determination ï² This project meets or exceeds the City of Arlington Complete Streets Standards. ï² This project will meet the City of Arlington Complete Street Standards with the following changes. ï² This project does not meet the City of Arlington Complete Street Standards. Please revisit the following sections and resubmit. Variance Determination ï² This project does not meet the City of Arlington Complete Street Standards. Project proponent has applied for a variance through the variance process and variance has been approved. ï² The variance has been denied, please revisit the following sections and resubmit. Page 7 of 7 Revised 8/18 Trailer Boss CONTRUCTION PLAN REVIEW & INSPECTION FEE WORKSHEET Community & Economic Development Department 18204 59th Avenue NE City of Arlington ï¬ ï¬ Arlington WA 98223 ï¬ (360) 403-3551 This form is to be completed and submitted with Type I , Type II Type III Construction Permit Application. 1) Based on permit type requested (Type I, Type II or Type III), complete the form as follows: ï¬ Type I permits complete all sections. ï¬ Type II permits complete as follows: - Grading Only - Complete Temporary Erosion and Sediment Control (TESC). - Stormwater Drainage Only - Complete the Temporary Erosion and Sediment Control and Stormwater Drainage Section for Public or Private ï¬ Type III permits complete the Temporary Erosion and Sediment Control (TESC). 2) The developer shall enter the quantities shown on the construction drawings into the Construction Calculation Worksheet. This document is used to determine the amount of plan reivew and inspection fees due to the city. 3) Excel will auto-calculate the relevant fields and subtotals throughout the document. Only the 'Quantity' columns should be completed. 4) The summary page calculates the fees due at intake for Civil and Stormwater Drainage construction permits only. This does not include fees for Grading or those required by other departments or agencies. Grading fees are based on Cubic Yard Quantity and shall be calculated at time of permit submittal. Grading fees shall be paid at permit submittal. 5) If an item that is part of your project does not exist in the spreadsheet complete the Write-In-Items section with the item, quantity and associated unit cost. There are a few unit prices that are blank, please complete them accordingly. 6) Inspection fees shall be calculated for Private Development during the review process and shall be paid upon permit issuance. PROJECT COSTS PUBLIC TOTAL PRIVATE TOTAL TOTAL PROJECT COST $ 50,055.63 $ 369,693.18 $ 419,748.81 Verify formula, totals do not match PLAN REVIEW & INSPECTION FEES PLAN REVIEW & INSPECTION FEE (6% of Project Value) $ 25,184.93 GRADING FEE (4) (Cubic Yard ) $ - Review fees due at time of submittal Total Review Fees Due $ 25,184.93 An Assurance Device such as a Performance Bond or Assignment of Funds needs to be on file with the City of Arlington prior to permit issuance. The Assurance Device shall be 150% of the Construction Calculation Worksheet which are as follows: ï¬ Road and Alley (Public) ï¬ Stormwater Drainage and Grading (Public) ï¬ Utilities (Public) ï¬ Temporary Erosion and Sediment Control (Public and Private) ASSURANCE DEVICE Base Calculation of Performance Device $ 50,055.63 PERFORMANCE DEVICE 150% Amount Due $ 75,083.44 Base Calculation of Maintenance Device $ 41,386.88 MAINTENANCE DEVICE 20% Amount Due $ 8,277.38 1 Rev 7/2017 CONSTRUCTION CALCULATION WORKSHEET TEMPORARY EROSION & SEDIMENT CONTROL Include Public Improvements & Private Development Description Unit Price Unit Quantity Cost Reference # Backfill & compaction-embankment $ 6.50 CY $ - Check dams $ 78.00 EACH $ - BMP C207 Catch Basin Protection $ 35.50 EACH 10 $ 355.00 Crushed surfacing 1 1/4" minus $ 18.00 TON $ - WSDOT 9-03.9(3) Ditching $ 8.00 CY $ - Excavation-bulk $ 3.00 CY $ - Fence, silt $ 2.00 LF 190 $ 380.00 BMP C233 Fence, Temporary (NGPA) $ 2.00 LF $ - Geotextile Fabric $ 2.50 SY $ - Hay Bale Silt Trap $ 0.50 EACH $ - Hydroseeding $ 4,200.00 ACRE $ - BMP C120 Interceptor Swale / Dike $ 1.00 LF $ - Jute Mesh $ 2.00 SY $ - BMP C122 Level Spreader $ 1.75 LF $ - Mulch, by hand, straw, 3" deep $ 3.00 SY $ - BMP C121 Mulch, by machine, straw, 2" deep $ 1.00 SY $ - BMP C121 Piping, temporary, CPP, 6" $ 12.50 LF $ - Piping, temporary, CPP, 8" $ 19.00 LF $ - Piping, temporary, CPP, 12" $ 24.00 LF $ - Plastic covering, 6mm thick, sandbagged $ 3.00 SY $ - BMP C123 Rip Rap, machine placed; slopes $ 50.00 CY $ - WSDOT 9-13.1(2) Rock Construction Entrance, 50'x15'x1' $ 1,800.00 EACH $ - BMP C105 Rock Construction Entrance, 100'x15'x1' $ 3,600.00 EACH 1 $ 3,600.00 BMP C105 Sediment pond riser assembly $ 3,050.00 EACH $ - BMP C241 Sediment trap, 5' high berm $ 21.00 LF $ - BMP C240 Sed. trap, 5' high, riprapped spillway berm section $ 79.00 LF $ - BMP C240 Seeding, by hand $ 1.00 SY $ - BMP C120 Sodding, 1" deep, level ground $ 8.00 SY $ - BMP C120 Sodding, 1" deep, sloped ground $ 9.50 SY $ - BMP C120 TESC Supervisor $ 84.00 HR $ - Water truck, dust control $ 130.00 HR 20 $ 2,600.00 BMP C140 WRITE-IN-ITEMS $ - $ - $ - $ - $ - $ - SUBTOTAL (TESC Only): $ 6,935.00 MOBILIZATION 10%: $ 693.50 CONTINGENCY 15%: $ 1,040.25 TOTAL: $ 8,668.75 Rev 7/2017 CONSTRUCTION CALCULATION WORKSHEET STORMWATER DRAINAGE Public Private Public Improvements Private Development Description Unit Price Unit Quantity Cost Quantity Cost Access Road, Retention / Detention $ 26.00 SY $ - $ - * (CBs include frame and lid) Beehive $ 90.00 EACH $ - $ - CB Type I $ 1,650.00 EACH $ - $ - CB Type IL $ 1,850.00 EACH $ - 5 $ 9,250.00 CB Type II, 48" Dia $ 2,550.00 EACH $ - $ - for additional depth over 4' $ 650.00 FT $ - $ - CB Type II, 54" Dia $ 2,700.00 EACH $ - $ - for additional depth over 4' $ 600.00 FT $ - $ - CB Type II, 60" Dia $ 2,900.00 EACH $ - $ - for additional depth over 4' $ 750.00 FT $ - $ - CB Type II, 72" Dia $ 4,000.00 EACH $ - $ - for additional depth over 4' $ 900.00 FT $ - $ - Through-curb Inlet Framework (Add) $ 550.00 EACH $ - $ - Cleanout, PVC, 4" $ 200.00 EACH $ - $ - Cleanout, PVC, 6" $ 250.00 EACH $ - $ - Cleanout, PVC, 8" $ 300.00 EACH $ - $ - Culvert, Box __ ft x __ ft $ - LS $ - $ - Culvert, PVC, 4" $ 12.00 LF $ - $ - Culvert, PVC, 6" $ 17.00 LF $ - $ - Culvert, PVC, 8" $ 19.00 LF $ - $ - Culvert, PVC, 12" $ 30.00 LF $ - $ - Culvert, CMP, 8" $ 23.00 LF $ - $ - Culvert, CMP, 12" $ 35.00 LF $ - $ - Culvert, CMP, 15" $ 42.00 LF $ - $ - Culvert, CMP, 18" $ 47.00 LF $ - $ - Culvert, CMP, 24" $ 69.00 LF $ - $ - Culvert, CMP, 30" $ 100.00 LF $ - $ - Culvert, CMP, 36" $ 150.00 LF $ - $ - Culvert, CMP, 48" $ 194.00 LF $ - $ - Culvert, CMP, 60" $ 310.00 LF $ - $ - Culvert, CMP, 72" $ 400.00 LF $ - $ - Culvert, Concrete, 8" $ 36.00 LF $ - $ - Culvert, Concrete, 12" $ 43.00 LF $ - $ - Culvert, Concrete, 15" $ 52.00 LF $ - $ - Culvert, Concrete, 18" $ 55.00 LF $ - $ - Culvert, Concrete, 24" $ 85.00 LF $ - $ - Culvert, Concrete, 30" $ 136.00 LF $ - $ - Culvert, Concrete, 36" $ 165.00 LF $ - $ - Culvert, Concrete, 42" $ 196.00 LF $ - $ - Culvert, Concrete, 48" $ 210.00 LF $ - $ - Culvert, CPP, 6" $ 16.00 LF $ - $ - Culvert, CPP, 8" $ 22.00 LF $ - $ - Culvert, CPP, 12" $ 28.00 LF $ - $ - Culvert, CPP, 15" $ 34.00 LF $ - $ - Culvert, CPP, 18" $ 39.00 LF $ - $ - Rev 7/2017 CONSTRUCTION CALCULATION WORKSHEET Culvert, CPP, 24" $ 49.00 LF $ - $ - Culvert, CPP, 30" $ 62.00 LF $ - $ - Culvert, CPP, 36" $ 69.00 LF $ - $ - Ditching $ 12.00 CY $ - $ - Flow Dispersal Trench (1,436 base+) $ 40.00 LF $ - $ - French Drain (3' depth) $ 39.00 LF $ - $ - Geotextile, laid in trench, polypropylene $ 5.00 SY $ - 220 $ 1,100.00 Infiltration pond testing $ 125.00 HR $ - $ - Mid-tank Access Riser, 48" dia, 6' deep $ 2,025.00 EACH $ - $ - Pipe, High Density Water Pipe (HDWP) $ 160.00 LF $ - $ - Pipe, C900 $ 90.00 LF $ - $ - Pond Overflow Spillway $ 18.00 SY $ - $ - Restrictor/Oil Separator, 12" $ 1,500.00 EACH $ - $ - Restrictor/Oil Separator, 15" $ 1,550.00 EACH $ - $ - Restrictor/Oil Separator, 18" $ 1,680.00 EACH $ - $ - Riprap, placed $ 52.00 CY $ - $ - Tank End Reducer (36" Dia) $ 1,280.00 EACH $ - $ - Thru-Inlet at CB $ 150.00 EACH $ - $ - Trash Rack, 12" $ 320.00 EACH $ - $ - Trash Rack, 15" $ 325.00 EACH $ - $ - Trash Rack, 18" $ 350.00 EACH $ - $ - Trash Rack, 21" $ 375.00 EACH $ - $ - WRITE-IN-ITEMS 6" PVC Perf Pipe $ 18.70 LF $ - 303 $ 5,666.10 Infiltatration Trench Gravel $ 16.00 CY $ - 615 $ 9,840.00 $ - $ - $ - SUBTOTAL: $ - $ 25,856.10 MOBILIZATION 10%: $ - CONTINGENCY 15%: $ - TOTAL: $ - $ 25,856.10 Rev 7/2017 CONSTRUCTION CALCULATION WORKSHEET GENERAL ITEMS Public Improvements Private Development Description Unit Price Unit Quantity Cost Quantity Cost Backfill & Compaction- embankment $ 8.00 CY $ - $ - Backfill & Compaction- trench $ 11.00 CY $ - $ - Clear/Remove Brush, by hand (acre) $ 2,363.00 ACRE $ - $ - Bollards - fixed $ 325.00 EACH $ - $ - Bollards - removable $ 600.00 EACH $ - $ - Clearing/Grubbing/Tree Removal $ 6,000.00 ACRE $ - $ - Excavation - bulk $ 2.50 CY $ - 900 $ 2,250.00 Excavation - Trench $ 5.00 CY $ - $ - Fencing, cedar, 6' high $ 25.00 LF $ - $ - Fencing, chain link, 4' $ 19.50 LF $ - $ - Fencing, chain link, vinyl coated, 6' high $ 18.00 LF $ - $ - Fencing, chain link, gate, vinyl coated, 2 $ 1,563.00 EACH $ - $ - Fencing, split rail, 3' high $ 14.00 LF $ - $ - Fill & compact - common barrow $ 27.00 CY $ - $ - Fill & compact - gravel base $ 30.00 CY $ - $ - Fill & compact - screened topsoil $ 45.00 CY $ - $ - Gabion, 12" deep, stone filled mesh $ 62.00 SY $ - $ - Gabion, 18" deep, stone filled mesh $ 86.00 SY $ - $ - Gabion, 36" deep, stone filled mesh $ 152.00 SY $ - $ - Grading, fine, by hand $ 2.00 SY $ - $ - Grading, fine, with grader $ 1.25 SY $ - $ - Guard Post $ 90.00 EACH $ - $ - Monuments $ 104.00 EACH $ - $ - Sensitive Areas Sign $ 20.00 EACH $ - $ - Sodding, 1" deep, sloped ground $ 10.00 SY $ - $ - Topsoil Type A (imported) $ 30.00 CY $ - $ - Traffic control crew ( 2 flaggers ) $ 98.00 HR $ - $ - Trail, 4" chipped wood $ 9.00 SY $ - $ - Trail, 4" crushed cinder $ 10.00 SY $ - $ - Trail, 4" top course $ 9.50 SY $ - $ - Wall, retaining, concrete $ 66.00 SF $ - $ - Wall, rockery $ 13.00 SF $ - $ - WRITE-IN-ITEMS Backfill and Compaction $ 5.00 CY $ - 900 $ 4,500.00 $ - $ - $ - $ - $ - $ - Subtotal $ - Subtotal $ 6,750.00 Rev 7/2017 CONSTRUCTION CALCULATION WORKSHEET STREET IMPROVEMENT Public Improvements Private Development Description Unit Price Unit Quantity Cost Quantity Cost AC Grinding, 4' wide machine < 1000sy $ 35.00 SY $ - $ - AC Grinding, 4' wide machine 1000-2000$ 8.50 SY $ - $ - AC Grinding, 4' wide machine > 2000sy $ 2.50 SY $ - $ - AC Removal/Disposal/Repair $ 60.00 SY $ - $ - Barricade, Type I $ 36.00 LF $ - $ - Barricade Type II $ 25.00 LF $ - $ - Barricade, Type III ( Permanent ) $ 55.00 LF $ - $ - Conduit, 2" $ 5.00 LF $ - $ - Curb & Gutter, rolled $ 20.00 LF $ - $ - Curb & Gutter, vertical $ 15.00 LF 47 $ 705.00 $ - Curb and Gutter, demolition and disposa $ 20.00 LF 47 $ 940.00 $ - Curb, extruded asphalt $ 5.00 LF $ - $ - Curb, extruded concrete $ 4.50 LF $ - $ - Guard Rail $ 30.00 LF $ - $ - Sawcut, asphalt, 3" depth $ 3.50 LF 47 $ 164.50 $ - Sawcut, concrete, per 1" depth $ 3.00 LF $ - $ - Sealant, asphalt $ 2.00 LF $ - $ - Shoulder, gravel, 4" thick $ 11.00 SY $ - $ - Sidewalk, 4" thick $ 40.00 SY $ - $ - Sidewalk, 4" thick, demolition and dispos $ 36.00 SY $ - $ - Sidewalk, 6" thick $ 45.00 SY 26 $ 1,175.00 $ - Sidewalk, 6" thick, demolition and dispos $ 45.00 SY 26 $ 1,175.00 $ - Signs $ - LS $ - $ - Sign, Handicap $ 100.00 EACH $ - 1 $ 100.00 Striping, per stall $ 7.50 EACH $ - 10 $ 75.00 Street Light System $ 3,000.00 EACH $ - 7 $ 21,000.00 Traffic Signal $ - LS $ - $ - Traffic Signal Modification $ - LS $ - $ - Striping, thermoplastic, ( for crosswalk ) $ 3.50 SF $ - $ - Striping, 4" reflectorized line $ 0.40 LF $ - $ - AC Patching/Trenching Restoration $ 100.00 TON $ - $ - Controlled Density Fill (CDF) $ 90.00 CY $ - $ - WRITE-IN-ITEMS $ - $ - $ - $ - $ - $ - $ - $ - $ - Subtotal $ 4,159.50 Subtotal $ 21,175.00 Rev 7/2017 CONSTRUCTION CALCULATION WORKSHEET STREET SURFACING/PAVEMENT Public Improvements Private Development Description Unit Price Unit Quantity Cost Quantity Cost Asphalt Overlay, 1.5" AC $ 12.00 SY $ - $ - Asphalt Overlay, 2" AC $ 15.00 SY $ - $ - Asphalt Road 2", First 2500 SY $ 10.00 SY $ - $ - Asphalt Road 2", Qty. over 2500SY $ 9.00 SY $ - $ - Asphalt Road 3", First 2500 SY $ 15.00 SY $ - $ - Asphalt Road 3", Qty. over 2500 SY $ 13.00 SY $ - $ - Asphalt Road 5", First 2500 SY $ 22.00 SY $ - $ - Asphalt Road 5", Qty. Over 2500 SY $ 22.00 SY $ - $ - Asphalt Road 6", First 2500 SY $ 25.00 SY $ - $ - Asphalt Road 6", Qty. Over 2500 SY $ 24.00 SY $ - $ - Asphalt Treated Base, 4" thick $ 14.00 SY $ - $ - Gravel Base Course 2" $ 7.50 SY $ - $ - Gravel Base Course 4" $ 15.00 SY $ - 9361 $ 140,420.00 Gravel Base Course 6" $ 22.50 SY $ - $ - Gravel Road, 4" rock, First 2500 SY $ 15.00 SY $ - $ - Gravel Road, 4" rock, Qty. over 2500 SY $ 11.00 SY $ - $ - Concrete Road, 5", no base, over 2500 S$ 22.00 SY $ - $ - Concrete Road, 6", no base, over 2500 $ 32.00 SY $ - $ - Thickened Edge $ 11.00 LF $ - $ - WRITE-IN-ITEMS Asphalt Road 2.5", First 2500 SY $ 12.50 SY $ - 2500 $ 31,250.00 Asphalt Road 2.5", Qty. over 2500SY$ 11.00 SY $ - 6861 $ 75,474.67 $ - $ - $ - Subtotal $ - Subtotal $ 247,144.67 Rev 7/2017 CONSTRUCTION CALCULATION WORKSHEET WATER SYSTEM Public Improvements Private Development Description Unit Price Unit Quantity Cost Quantity Cost Blowoff $ 1,800.00 EACH $ - $ - Connection to Existing Water Main $ 2,000.00 EACH $ - $ - Ductile Iron Watermain, CL 52, 6 Inch Dia $ 65.00 LF $ - $ - Ductile Iron Watermain, CL 52, 8 Inch Dia $ 85.00 LF $ - $ - Ductile Iron Watermain, CL 52, 10 Inch Dia $ 103.00 LF $ - $ - Ductile Iron Watermain, CL 52, 12 Inch Dia. $ 125.00 LF $ - $ - Gate Valve, 6 inch Dia $ 250.00 EACH $ - $ - Gate Valve, 8 Inch Dia $ 380.00 EACH $ - $ - Gate Valve, 10 Inch Dia $ 425.00 EACH $ - $ - Gate Valve, 12 Inch Dia $ 500.00 EACH $ - $ - Fire Hydrant Assembly, with Guard Posts $ 3,000.00 EACH $ - $ - Fire Hydrant Assembly, without Guard Posts $ 2,500.00 EACH $ - $ - Air-Vac, 8 Inch Dia $ 6,000.00 EACH $ - $ - Air-Vac,10 Inch Dia $ 7,500.00 EACH $ - $ - Air-Vac, 12 Inch Dia $ 12,000.00 EACH $ - $ - Pressure Reducing Valve Assembly, 8 In. Dia $ 3,800.00 EACH $ - $ - Pressure Reducing Valve Assembly, 10 In. D $ 4,200.00 EACH $ - $ - Pressure Reducing Valve Assembly, 12 In. D $ 5,000.00 EACH $ - $ - Valve Marker Post $ 350.00 EACH $ - $ - WRITE-IN-ITEMS $ - $ - $ - $ - $ - $ - $ - $ - Subtotal $ - Subtotal $ - Rev 7/2017 CONSTRUCTION CALCULATION WORKSHEET SANITARY SEWER Public Improvements Private Development Description Unit Price Unit Quantity Cost Quantity Cost Connection to Existing Sewer Main $ - EACH $ - $ - Clean Outs $ 500.00 EACH $ - $ - Grease Interceptor, 500 gallon $ 6,000.00 EACH $ - $ - Grease Interceptor, 1000 gallon $ 10,000.00 EACH $ - $ - Grease Interceptor, 1500 gallon $ 15,000.00 EACH $ - $ - Side Sewer Pipe, PVC. 4 Inch Dia $ 8.00 LF $ - $ - Side Sewer Pipe, PVC. 6 Inch Dia $ 12.00 LF $ - $ - Sewer Pipe, PVC, 8 inch Dia $ 33.00 LF $ - $ - Sewer Pipe, PVC, 12 Inch Dia $ 41.00 LF $ - $ - Sewer Pipe, PVC, ____ Inch Dia $ - LF $ - $ - Lift Station (Entire System) $ - LS $ - $ - Manhole, 48 Inch Dia $ 3,000.00 EACH $ - $ - for additional depth over 4 feet/per fo $ 532.00 FEET $ - $ - Manhole, 54 Inch Dia $ 3,500.00 EACH $ - $ - for additional depth over 4 feet/per fo $ 532.00 FEET $ - $ - Manhole, 60 Inch Dia $ 3,700.00 EACH $ - $ - for additional depth over 4 feet/per fo $ 532.00 FEET $ - $ - Manhole, 72 Inch Dia $ 4,000.00 EACH $ - $ - for additional depth over 4 feet/per fo $ 625.00 FEET $ - $ - Manhole, 96 Inch Dia $ 5,000.00 EACH $ - $ - for additional depth over 4 feet/per foo $ 625.00 FEET $ - $ - Outside Drop $ - LS $ - $ - Inside Drop $ - LS $ - $ - Pipe, C-900 $ 90.00 LF $ - $ - Pipe, High Density Water Pipe (HDWP) $ 160.00 LF $ - $ - WRITE-IN-ITEMS $ - $ - $ - $ - $ - $ - $ - $ - $ - Subtotal $ - Subtotal $ - Rev 7/2017 CONSTRUCTION CALCULATION WORKSHEET LANDSCAPING & VEGETATION Include Public Improvements & Private Development Description Unit Price Unit Quantity Cost Street Trees $ 500.00 EACH 49 $ 24,500.00 Root Barrier $ 50.00 EACH 49 $ 2,450.00 Median Landscaping $ - LS $ - Right-of-Way Landscaping $ 1,000.00 LS 1 $ 1,000.00 Wetland Landscaping $ - LS $ - Private Landscaping $ 1,000.00 LS 1 $ 1,000.00 WRITE-IN-ITEMS $ - $ - $ - $ - $ - $ - Subtotal $ 28,950.00 (INCLUDES GENERAL, STREET, SURFACING, WATER, PUBLIC PRIVATE SEWER, LANDSCAPING) SUBTOTAL $ 33,109.50 $ 275,069.67 MOBILIZATION 10%: $ 3,310.95 $ 27,506.97 CONTINGENCY 15%: $ 4,966.43 $ 41,260.45 GRANDTOTAL: $ 41,386.88 $ 343,837.08 Rev 7/2017 Stormwater Management Report December 17, 2019 Trailer Boss Development Prepared for: Fine Family Trust 3030 137th Lane SW Tenino, WA 98589 (360) 508-9583 Prepared by: 12/17/2019 TerraVista NW L L C C o n s u l t i n g E n g i n e e r s 3204 Smokey Point Dr., www.TerraVistaNW.com Suite 207 (425) 422-0840 Arlington, WA 98223 TerraVista NW,LLC Stormwater Management Report Table of Contents Stormwater Management Report.......................................................................................................................1 Project Overview............................................................................................................................................2 Site Location..............................................................................................................................................2 Code Compliance.......................................................................................................................................2 Executive Summary.......................................................................................................................................3 Pervious/Impervious Areas............................................................................................................................3 Onsite Pervious / Impervious Area............................................................................................................4 Soils................................................................................................................................................................3 Minimum Stormwater Management Requirements.......................................................................................3 Overview of Minimum Requirements........................................................................................................5 1-Preparation of Stormwater Site Plans.....................................................................................................6 2-Construction Stormwater Pollution Prevention Plan (SWPPP)..............................................................6 3-Source Control of Pollution....................................................................................................................6 4-Preservation of Natural Drainage Systems and Outfalls.........................................................................6 5-Onsite Stormwater Management.............................................................................................................7 6-Runoff Treatment....................................................................................................................................9 7-Flow Control...........................................................................................................................................9 8-Wetland Protection..................................................................................................................................9 9-Operation and Maintenance....................................................................................................................9 Appendix A â€“ Stormwater Pollution Prevention Plan Appendix B â€“ Soils Report Appendix C â€“ Operation and Maintenance Appendix D â€“Infiltration Trench Drainage Calculations (190403)Trailer Boss Page1 December 17, 2019 TerraVista NW,LLC Stormwater Management Report Project Overview Site Location The project is locatedat the corner of Smokey Point Blvd and 166th Pl on a 2.28 acre site. Code Compliance The project will comply with: Â· [WSDOT] STANDARD SPECIFICATIONS for ROAD, BRIDGE and MUNICIPAL CONSTRUCTION,WSDOT, 2018 Editionwith amendments Â· [ADCS]Arlington Design and Construction Standards, dated July 2008 Â· [AMC]Arlington Municipal Code Â· [SWMMWW] 2012/14 Stormwater Management Manual for Western Washington (190403)Trailer Boss Page2 December 17, 2019 TerraVista NW,LLC Stormwater Management Report Executive Summary The proposed project will be a developing of a retail sales site for utility trailers. The project site is made up of two parcels totaling 2.28 acres combined. An office building will be placed next to Smokey Point Blvd and a maintenance shop will be placed in the back of the facility. 10 parking stalls will be provided for staff and customers, and the remaining portions of the site will be used for product display of utility trailers. The site will also include require landscaping. Stormwater mitigation will be addressed though infiltration facilities. The ground water elevation is fairly high at this location, therefore the site will be raised to provide the required separation between infiltration and groundwater table. Existing Conditions The existing site is currently cleared of all vegetation. The front half of the site is gravel while the back half is exposed soil. Smokey Point Blvd borders the site on the west, 166th Place borders the site on the north, the Snohomish County PUD substation borders the east side, and a vacant lot borders the south side. Soils The test pits conducted for this study encountered native silty sands and sands beneath a thin layer of fill soil or topsoil. Underlying the fill and/or topsoil, we observed weathered silty sand soils that were loose. The fill and weathered soil was approximately 1 to 2.5 feet deep, and beneath these soils tan, medium dense, native, slightly silty sand was encountered. Beneath the tan sands, we encountered dense, gray sand that extended to the bottom of all of the pits (6 footmax explored depth at the site). This sand soil is typical for the native conditions encountered in the general vicinity. Based on the soil explorations performed by Materials Testing and Consulting, groundwater was encountered approximately 5-7â€™ below grade, depending on the location. The elevation of the groundwater table at the time of exploration wasextrapolated to be approximately elevation 113â€™, based on the depth measurements and the ground elevation at the test pit locations. Refer to soils report in Appendix B for additional information. Proposed Conditions The proposed project will be a developing of a retail sales site for utility trailers. The project site is made up of two parcels totaling 2.28 acres combined. An office building will be placed next to Smokey Point Blvd and a maintenance shop will be placed in the back of the facility. 10 parking stalls will be provided for staff and customers, and the remaining portions of the site will be used for product display of utility trailers. The site will also include require landscaping. Stormwater facilities will utilize infiltration. Due to the high groundwater elevation a mounding analysis has been performed. (190403)Trailer Boss Page3 December 17, 2019 TerraVista NW,LLC Stormwater Management Report Pervious/Impervious Areas Refer to Figure 1 for a graphical depiction of tributary areas. For use in determining stormwater mitigation fees the following areas represent the true pervious/impervious area for the entire site. Onsite Pervious / Impervious Area Total impervious surfaceâ€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦..â€¦â€¦â€¦..â€¦2.03 ac Total pervious surfaceâ€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦..â€¦â€¦â€¦â€¦â€¦.â€¦..0.25 ac TOTAL ONSITE AREAâ€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦..â€¦â€¦â€¦â€¦â€¦â€¦â€¦..2.28 ac (190403)Trailer Boss Page4 December 17, 2019 TerraVista NW,LLC Stormwater Management Report Minimum Stormwater Management Requirements Overview of Minimum Requirements Minimum requirements 1-9 shall apply to the project. (190403)Trailer Boss Page5 December 17, 2019 TerraVista NW,LLC Stormwater Management Report 1-Preparation of Stormwater Site Plans Stormwater site plans were prepared in accordance with Volume I, Chapter 3 of the SWMMWW. 2-Construction Stormwater Pollution Prevention Plan (SWPPP) A SWPPP narrative has been prepared and is included in Appendix A and on the plan set. The erosion potential for the site is very low to non-existent. The onsite soils are highly infiltratable so no runoff during construction is anticipated. 3-Source Control of Pollution The project will not pose any source of pollution for the site other than concrete for the building foundations. The site is not considered a high use site. The SWPPP provided will address the source control of pollution during the construction phase. 4-Preservation of Natural Drainage Systems and Outfalls Existing regionaldrainageinfiltrates into the soils. Proposed drainagesystemwill alsoinfiltrate, therefore, preservation of natural drainage systems and outfall is being met. (190403)Trailer Boss Page6 December 17, 2019 TerraVista NW,LLC Stormwater Management Report 5-Onsite Stormwater Management (190403) Trailer Boss Page 7 December 17, 2019 TerraVista NW,LLC Stormwater Management Report A Drainage Summary Sheet and Figure 1 are enclosed detailing the parameters of each drainage system. All drainage systems are designed to infiltrate 100% of the stormwater therefore meeting and exceeding the LID stormwater requirements including other minimum requirements. Detailed drainage calculations for onsite and offsite facilities are provided in the appendices. As each drainage facility is essentially identical to each other in function and calculation methodology, a single gravel infiltration trench was modeled as the basis of the design. Each drainage system onsite was determined based on a proration of the modeled facility. For ease of calculation, the model area was 1- acre with a facility thicknessof 2â€™ of drain rock. The model determined that the required size of any infiltration trench/mat for this project would need to be 2,275 sf/acre of tributary area. As shown in the attached Drainage Summary Sheet, 2,275sf/acre was divided by the proposed width of each tributary area to determine the required minimum length of the individual facility. SSC-4 of the SWMMWW requires that infiltration facilities that are utilized for treatment purposes must document that the water quality design storm volume (indicated by WWHM or MGS Flood, or runoff from a 6-month, 24-hour rain event) can infiltrate through the infiltration basin surface within 48 hours. The infiltrationfacilities are designed to infiltrate 100% of the stormwater within the 2â€™ depth of the storage layer. The water quality storm, which is less than the all storms contained within the model, will also be contained within the 2â€™ storage layer of the infiltration trench. SSC-4 is therefore met. Upstream Analysis The surrounding area has flat topography with high infiltration soils. No stormwater from offsite areas are anticipated to flow onto the project site. Downstream Analysis The proposed storm drain mitigation for the project site will infiltrate 100% of the stormwater. Therefore, no impacts to the downstream system are anticipated. In the event that onsite drainage systems are overwhelmed by excessive rainfall, the stormwater will primarily continue to stay onsite due to the topography of the site, with the exception of the south- western property line adjacent to the residential property. In the event the storm system is overwhelmed, some amount of water may spill over into the side yard of the residence. Overall, stormwater will not back up into the buildings. (190403)Trailer Boss Page8 December 17, 2019 TerraVista NW,LLC Stormwater Management Report BMP T5.13: Post-Construction Soil Quality and Depth BMP T5.13 is required as part of Minimum Requirement #5. Although the Contractor has the option of stockpiling existing topsoil material, itis anticipated that the Contractor will import topsoil material to meet the requirements of BMP T5.13. 6-Runoff Treatment The site will meet the basic level of treatment, as the project does not meet the thresholds for enhanced treatment, phosphorousremoval, or oil treatment as described in Section V-3 of the SWMMWW. Pollutant generating impervious areas (PGIS) will drain to a series of infiltration trenches that utilize an 18â€ layer of sand for filtration, as the existing soils do not meet the site suitability requirements of SSC- 6. The sand layer will be below the gravel infiltration trench. The system is similar to that used by permeable pavements for treatment, as part of BMP T5.15, whereby stormwater passes through a gravel storage layer, followed by a sand layer, and then final infiltration into the native soil. Pretreatment for the infiltration systems in the middle of the site will include the use of sand/oil water separators at each catch basin, in accordance with the Cityâ€™s standard detail SD-120. Pretreatment for the linear â€œFrench Drainâ€ system along the property lines will include a sump to capture sediment, as well as a surface gravel layer to trap sediment before entering the system. 7-Flow Control This is being met with 100% infiltration of the stormwater onsite. 8-Wetland Protection No wetlands are present on the site or within the adjacent downstream area. 9-Operation and Maintenance Operation and maintenance procedures are included in AppendixC. (190403)Trailer Boss Page9 December 17, 2019 FIGURE 1 â€“ TRIBUTARY AREAS Drainage Information Summary Project Name: SMARTCAP 188th Development Onsite Project Total Area: 2.28 acres Offsite Project Total Area: 0.18 acres Number of Lots (if applicable): 2 Infiltration Proration 2,275 sf/acre @ 2' depth (Note: For conservatism, subbasins were modeled as 100% imperv.; parking subbasins were modeled as 100% pollutant generating) Drainage Basin Information Total Area of Impact 0.05 0.65 0.01 0.52 0.42 0.07 0.39 0.17 2.28 Existing Condition Area (ac) Pervious Area 0.05 0.42 0.07 0.39 0.17 1.1 Impervious Area 0.65 0.01 0.52 1.18 Proposed Condition Area (ac) Pervious Area Impervious Area Non-pollution Generating 0.05 0.04 0.01 0.1 Pullution Generating 0.61 0.52 0.42 0.07 0.39 0.17 2.18 Infiltration Facility Sizing (prorated) Thickness (ft) 2 2 2 2 2 2 2 Width (ft) 2.0 5.0 5.5 4.5 2.0 5.5 4.0 Min Length (ft) 57 296 215 212 80 161 96 Pre-developed Runoff Rates Q (cfs) 2 Year 10 year 100 year Post-developed Runoff Rates Q (cfs) 2 Year 10 year 100 year Offsite Upstream Area 0 0 0 0 0 0 0 0 Type of Storage Proposed Infilt. Infilt. NA Infilt. Infilt. Infilt. Infilt. Infilt. Approx. Storage Volume (cu-ft) NA NA NA NA NA NA NA NA Type of Treatment NA Sand NA Sand Sand Sand Sand Sand Low Impact Development Yes Yes NA Yes Yes Yes Yes Yes TerraVista NW,LLC Appendix A Construction Stormwater Pollution Prevent Plan (SWPPP) Construction Stormwater General Permit (CSWGP) Stormwater Pollution Prevention Plan (SWPPP) for Trailer Boss Prepared for: Department of Ecology Northwest Region Permittee / Owner Developer Operator / Contractor Trailer Boss Same Pending [Insert Project Site Location] Update as necessary. Certified Erosion and Sediment Control Lead (CESCL) Name Organization Contact Phone Number Pending Pending Pending SWPPP Prepared By Name Organization Contact Phone Number Eric Scott TerraVista NW 425-422-0840 SWPPP Preparation Date Month / Day / Year Project Construction Dates Activity / Phase Start Date End Date Construction March 2020 Aug 2020 List of Acronyms and Abbreviations Acronym / Abbreviation Explanation 303(d) Section of the Clean Water Act pertaining to Impaired Waterbodies BFO Bellingham Field Office of the Department of Ecology BMP(s) Best Management Practice(s) CESCL Certified Erosion and Sediment Control Lead CO2 Carbon Dioxide CRO Central Regional Office of the Department of Ecology CSWGP Construction Stormwater General Permit CWA Clean Water Act DMR Discharge Monitoring Report DO Dissolved Oxygen Ecology Washington State Department of Ecology EPA United States Environmental Protection Agency ERO Eastern Regional Office of the Department of Ecology ERTS Environmental Report Tracking System ESC Erosion and Sediment Control GULD General Use Level Designation NPDES National Pollutant Discharge Elimination System NTU Nephelometric Turbidity Units NWRO Northwest Regional Office of the Department of Ecology pH Power of Hydrogen RCW Revised Code of Washington SPCC Spill Prevention, Control, and Countermeasure su Standard Units SWMMEW Stormwater Management Manual for Eastern Washington SWMMWW Stormwater Management Manual for Western Washington SWPPP Stormwater Pollution Prevention Plan TESC Temporary Erosion and Sediment Control SWRO Southwest Regional Office of the Department of Ecology TMDL Total Maximum Daily Load VFO Vancouver Field Office of the Department of Ecology WAC Washington Administrative Code WSDOT Washington Department of Transportation WWHM Western Washington Hydrology Model Project Information (1.0) Project/Site Name: Trailer Boss Street/Location: Smokey Point Blvd City: Arlington State: WA Zip code: 98223 Subdivision: Receiving waterbody: Groundwater Existing Conditions (1.1) Total acreage (including support activities such as off-site equipment staging yards, material storage areas, borrow areas). Total acreage: 2.28 acres Disturbed acreage: 2.28 acres Existing structures: None Landscape topography: Flat Drainage patterns: Infiltration Existing Vegetation: None Critical Areas (wetlands, streams, high erosion risk, steep or difficult to stabilize slopes): None List of known impairments for 303(d) listed or Total Maximum Daily Load (TMDL) for the receiving waterbody: None Table 1 includes a list of suspected and/or known contaminants associated with the construction activity. List all known or suspected contaminants associated with this site in Table 1. Include contaminants previously remediated. Table 1 â€“ Summary of Site Pollutant Constituents Constituent (Pollutant) Location Depth Concentration None [Insert Text] [Insert Text] [Insert Text] Proposed Construction Activities (1.2) Description of site development (example: subdivision): Commercial Development Description of construction activities (example: site preparation, demolition, excavation): Site preparation, demolition, excavation and fill, paving, and building construction Description of site drainage including flow from and onto adjacent properties. Must be consistent with Site Map in Appendix A: Stormwater drainage will utilize infiltration trenches to infiltrate 100% of the stormwater. Description of final stabilization (example: extent of revegetation, paving, landscaping): Site will be paved as well as gravel within landscape areas. Contaminated Site Information: Proposed activities regarding contaminated soils or groundwater (example: on-site treatment system, authorized sanitary sewer discharge): NA Construction Stormwater Best Management Practices (BMPs) (2.0) Describe the BMPs identified to control pollutants in stormwater discharges. Depending on the site, multiple BMPs for each element may be necessary. For each element identified: Â· Clearly describe the control measure(s). Â· Describe the implementation sequence. Â· Describe the inspection and maintenance procedures for that specific BMP. Â· Identify the responsible party for maintaining BMPs (if your SWPPP is shared by multiple operators, indicate the operator responsible for each BMP). Categorize each BMP under one of the following elements as listed below: 1. Preserve Vegetation / Mark Clearing Limits 2. Establish Construction Access 3. Control Flow Rates 4. Install Sediment Controls 5. Stabilize Soils 6. Protect Slopes 7. Protect Drain Inlets 8. Stabilize Channels and Outfalls 9. Control Pollutants 10.Control Dewatering 11.Maintain BMPs 12.Manage the Project 13.Protect Low Impact Development Â· BMPs must be consistent with the most current approved edition of the Stormwater Management Manual for Western Washington (SWMMWW) at sites west of the crest of the Cascade Mountains; the Stormwater Management Manual for Eastern Washington (SWMMEW) for sites east of the crest of the Cascade Mountains at the time the general permit was issued; or other Ecology-approved manual. Â· Note the location of each BMP on your Site Map in Appendix A. Â· Include the corresponding Ecology source control BMPs and runoff conveyance and treatment BMPs in Appendix B. o SWMMWW Volume II Chapter 4 Sections 4.1 and 4.2 â€“ https://fortress.wa.gov/ecy/publications/SummaryPages/1410055.html or o SWMMEW Chapter 7 Section 7.3.1 and 7.3.2 â€“ https://fortress.wa.gov/ecy/publications/summarypages/0410076.html o If it can be justified that a particular element does not apply to the project site, include a written justification in lieu of the BMP description in the text for the appropriate element. The SWPPP is a living document reflecting current conditions and changes throughout the life of the project. These changes may be informal (i.e. hand-written notes and deletions). Update the SWPPP when the CESCL has noted a deficiency in BMPs or deviation from original design. The 12 Elements (2.1) Element 1: Preserve Vegetation / Mark Clearing Limits (2.1.1) Describe the methods (signs, fences, etc,) you will use to protect those areas that should not be disturbed. Describe natural features identified and how each will be protected during construction. Trees that are to be preserved, as well as all sensitive areas and their buffers, shall be clearly delineated, both in the field and on the plans. Describe how natural vegetation and native topsoil will be preserved. List and describe BMPs: BMP C103 â€“ High Visibility Fence, BMP C233-Silt Fence Installation Schedules: Installed prior to ground breaking Inspection and Maintenance plan: Inspected weekly and after major precipitation event Responsible Staff: CESCL Element 2: Establish Construction Access (2.1.2) Describe how you will minimize dust generation and vehicles tracking sediment off-site. Limit vehicle access to one route, if possible. Recycled concrete used to establish construction ingress or egress may be a stormwater pollutant source that requires treatment prior to discharge. Street sweeping, street cleaning, or wheel wash/tire baths may be necessary if the stabilized construction access is not effective. All wheel wash wastewater shall be controlled on-site and CANNOT be discharged into waters of the State. Install site ingress/egress stabilization BMPs according to BMP C105. Describe how you will clean the affected roadway(s) from sediment which is tracked off-site. List and describe BMPs: BMP C105-Stabilized Construction Entrance Installation Schedules: installed at the start of construction Inspection and Maintenance plan: Inspected and maintained weekly or after significant rainfall event Responsible Staff: CESCL Element 3: Control Flow Rates (2.1.3) Describe how you will protect properties and waterways downstream of the project from increased speed and volume of stormwater discharges due to construction activity. Construction of stormwater retention and/or detention facilities must be done as one of the first steps in grading. Assure that detention facilities are functioning properly before constructing site improvements (i.e. impervious surfaces). If applicable, describe how you will protect areas designed for infiltration from siltation during the construction phase. Will you construct stormwater retention and/or detention facilities? Yes No Will you use permanent infiltration ponds or other low impact development (example: rain gardens, bio-retention, porous pavement) to control flow during construction? Yes No List and describe BMPs: None Installation Schedules: [Insert text here] Inspection and Maintenance plan: [Insert text here] Responsible Staff: [Insert text here] Element 4: Install Sediment Controls (2.1.4) Describe how you will minimize sediment discharges from the site. Construct sediment control BMPs as one of the first steps of grading. These BMPs must be functional before other land disturbing activities â€“ especially grading and filling â€“ take place. Describe the BMPs identified to filter sediment prior to it being discharged to an infiltration system or leaving the construction site. Describe how you will direct stormwater for maximum infiltration where feasible. Describe how you will not interfere with the movement of juvenile Salmonids attempting to enter off-channel areas or drainages. Describe how you will respond if sediment controls are ineffective and turbid water is observed discharging from the site. Consider the amount, frequency, intensity and duration of precipitation, soil characteristics, and site characteristics when selecting sediment control BMPs. List and describe BMPs: BMP C233-Silt Fence Installation Schedules: Installed at start of construction Inspection and Maintenance plan: Inspect weekly or after rainfall event Responsible Staff: CESCL Element 5: Stabilize Soils (2.1.5) Describe how you will stabilize exposed and unworked soils throughout the life of the project (i.e. temporary and permanent seeding, mulching, erosion control fabrics, etc.). Describe how you will stabilize soil stockpiles. Describe how you will minimize the amount of soil exposed throughout the life of the project. Describe how you will minimize the disturbance of steep slopes. Describe how you will minimize soil compaction. Describe how you will stabilize contaminated soil and contaminated soil stockpiles if applicable. Exposed and unworked soils will be stabilized according to the time period set forth for dry and wet seasons, on the west or east sides of the crest of the Cascade Mountains. Select your regionâ€™s table and delete the others. West of the Cascade Mountains Crest Number of Days Soils Can be Season Dates Left Exposed During the Dry Season May 1 â€“ September 30 7 days During the Wet Season October 1 â€“ April 30 2 days East of the Cascade Mountains Crest, except the Central Basin* Number of Days Soils Can be Season Dates Left Exposed During the Dry Season July 1 â€“ September 30 10 days During the Wet Season October 1 â€“ June 30 5 days The Central Basin*, East of the Cascade Mountain Crest Number of Days Soils Can be Season Dates Left Exposed During the Dry Season July 1 â€“ September 30 30 days During the Wet Season October 1 â€“ June 30 15 days *Note: The Central Basin is defined as the portions of Eastern Washington with mean annual precipitation of less than 12 inches. Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on the weather forecast. Anticipated project dates: Start date: March 2020 End date: Aug 2020 Will you construct during the wet season? Yes No List and describe BMPs: BMP C140-Dust Control Installation Schedules: Dust control will be used from beginning of construction to final stabiliazation of soi. Inspection and Maintenance plan: Inspect weekly Responsible Staff: CESCL Element 6: Protect Slopes (2.1.6) West of the Cascade Mountains Crest Describe how slopes will be designed, constructed, and protected to minimize erosion. Temporary pipe slope drains must handle the peak 10-minute flow rate from a Type 1A, 10- year, 24-hour frequency storm for the developed condition. Alternatively, the 10-year, 1-hour flow rate predicted by an approved continuous runoff model, increased by a factor of 1.6, may be used. The hydrologic analysis must use the existing land cover condition for predicting flow rates from tributary areas outside the project limits. For tributary areas on the project site, the analysis must use the temporary or permanent project land cover condition, whichever will produce the highest flow rates. If using the Western Washington Hydrology Model (WWHM) to predict flows, bare soil areas should be modeled as â€œlandscaped areaâ€. Describe how you will reduce scouring within constructed channels that are cut down a slope. East of the Cascade Mountain Crest Describe how slopes will be designed, constructed, and protected to minimize erosion. Temporary pipe slope drains must handle the expected peak flow velocity from a 6-month, 3- hour storm for the developed condition, referred to as the short duration storm. Describe how you will reduce scouring within constructed channels that are cut down a slope. Will steep slopes be present at the site during construction? Yes No List and describe BMPs: None Installation Schedules: Inspection and Maintenance plan: Responsible Staff: Element 7: Protect Drain Inlets (2.1.7) Describe how you will protect all operable storm drain inlets so that stormwater runoff does not enter the stormwater conveyance system. Describe how you will remove sediment that enters the stormwater conveyance system (i.e. filtration, treatment, etc.). Keep in mind inlet protection may function well for coarse sediment but is less effective in filtering finer particles and dissolved constituents. Inlet protection is the last component of a treatment train and protection of drain inlets include additional sediment and erosion control measures. Inlet protection devices will be cleaned (or removed and replaced), when sediment has filled the device by one third (1/3) or as specified by the manufacturer. Inlets will be inspected weekly at a minimum and daily during storm events. List and describe BMPs: BMP C220-Storm Drain Inlet Protection Installation Schedules: Installed prior to construction Inspection and Maintenance plan: Inspected weekly or after rain event Responsible Staff: CESCL Element 8: Stabilize Channels and Outlets (2.1.8) Describe how you will prevent downstream erosion where site runoff is to be conveyed in channels, discharged to a stream or, discharged to a natural drainage point. West of the Cascade Mountains Crest On-site conveyance channels must handle the peak 10-minute flow rate from a Type 1A, 10- year, 24-hour frequency storm for the developed condition. Alternatively, the 10-year, 1-hour flow rate predicted by an approved continuous runoff model, increased by a factor of 1.6, may be used. The hydrologic analysis must use the existing land cover condition for predicting flow rates from tributary areas outside the project limits. For tributary areas on the project site, the analysis must use the temporary or permanent project land cover condition, whichever will produce the highest flow rates. If using the WWHM to predict flows, bare soil areas should be modeled as â€œlandscaped areaâ€. Provide stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes, and downstream reaches, will be installed at the outlets of all conveyance systems. List and describe BMPs: None Installation Schedules: NA Inspection and Maintenance plan: NA Responsible Staff: NA Element 9: Control Pollutants (2.1.9) The following pollutants are anticipated to be present on-site: Table 2 â€“ Pollutants Pollutant (and source, if applicable) Concrete Describe how you will handle and dispose of all pollutants, including waste materials and demolition debris, in a manner that does not cause contamination of stormwater. Describe how you will cover, contain, and protect from vandalism all chemicals, liquid products, petroleum products, and other polluting materials. Describe how you will manage known contaminants to prevent their discharge with stormwater to waters of the State (i.e. treatment system, off-site disposal). Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on-site? Yes No Provisions of spill prevention plan will be used If yes, describe spill prevention and control measures in place while conducting maintenance, fueling, and repair of heavy equipment and vehicles. If yes, also provide the total volume of fuel on-site and capacity of the secondary containment for each fuel tank. Secondary containment structures shall be impervious. Will wheel wash or tire bath system BMPs be used during construction? Yes No If yes, provide disposalmethods for wastewater generated by BMPs. If discharging to the sanitary sewer, include the approval letter from your local sewer district under Correspondence in Appendix C. Will pH-modifying sources be present on-site? Yes No If yes, check the source(s). Table 3 â€“ pH-Modifying Sources None X Bulk cement Cement kiln dust Fly ash Other cementitious materials X New concrete washing or curing waters Waste streams generated from concrete grinding and sawing Exposed aggregate processes Dewatering concrete vaults X Concrete pumping and mixer washout waters Recycled concrete Other (i.e. calcium lignosulfate) [please describe] Describe BMPs you will use to prevent pH-modifying sources from contaminating stormwater. List and describe BMPs: BMP C151-Concrete Handling, BMP C152-Sawcutting, BMP C154-Concrete Washout Installation Schedules: Installed prior to concrete work being performed Inspection and Maintenance plan: Inspected weekly Responsible Staff: CESCL Adjust pH of stormwater if outside the range of 6.5 to 8.5 su. Obtain written approval from Ecology before using chemical treatment with the exception of CO2 or dry ice to modify pH. Concrete trucks must not be washed out onto the ground, or into storm drains, open ditches, streets, or streams. Excess concrete must not be dumped on-site, except in designated concrete washout areas with appropriate BMPs installed. Element 10: Control Dewatering (2.1.10) Describe where dewatering will occur, including source of the water to be removed. State clearly if dewatering water is contaminated or has the potential to be contaminated. Water from foundations, vaults, and trenches with characteristics similar to stormwater runoff shall be discharged into a controlled conveyance system before discharging to a sediment trap or sediment pond. Clean dewatering water will not be routed through stormwater sediment ponds. Only clean, non-turbid dewatering water (such as well-point groundwater) may be discharged to systems tributary to, or directly into, surface waters of the State, provided the dewatering flow does not cause erosion or flooding of receiving waters. Describe how you will manage dewatering water to prevent the discharge of contaminants to waters of the State, including dewatering water that has comingled with stormwater (i.e. treatment system, off-site disposal). Dewatering is anticipated for installation of side sewer connection. Water will be pumped out with a trash pump and dispersed onsite. No contamination is anticipated. Check treatment of disposal option for dewatering water, if applicable: Table 4 â€“ Dewatering BMPs Infiltration Transport off-site in a vehicle (vacuum truck for legal disposal) Ecology-approved on-site chemical treatment or other suitable treatment technologies Sanitary or combined sewer discharge with local sewer district approval (last resort) Use of sedimentation bag with discharge to ditch or swale (small volumes of localized dewatering) List and describe BMPs: NA Installation Schedules: NA Inspection and Maintenance plan: NA Responsible Staff: NA Element 11: Maintain BMPs (2.1.11) This section is a list of permit requirements and does not have to be filled out. All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained and repaired as needed to ensure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP specification (see Volume II of the SWMMWW or Chapter 7 of the SWMMEW). Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to once every calendar month. All temporary ESC BMPs shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be stabilized on-site or removed. Disturbed soil resulting from removal of either BMPs or vegetation shall be permanently stabilized. Additionally, protection must be provided for all BMPs installed for the permanent control of stormwater from sediment and compaction. BMPs that are to remain in place following completion of construction shall be examined and restored to full operating condition. If sediment enters these BMPs during construction, the sediment shall be removed and the facility shall be returned to conditions specified in the construction documents. Element 12: Manage the Project (2.1.12) The project will be managed based on the following principles: Â· Projects will be phased to the maximum extent practicable and seasonal work limitations will be taken into account. Â· Inspection and monitoring: o Inspection, maintenance and repair of all BMPs will occur as needed to ensure performance of their intended function. o Site inspections and monitoring will be conducted in accordance with Special Condition S4 of the CSWGP. Sampling locations are indicated on the Site Map. Sampling station(s) are located in accordance with applicable requirements of the CSWGP. Â· Maintain an updated SWPPP. o The SWPPP will be updated, maintained, and implemented in accordance with Special Conditions S3, S4, and S9 of the CSWGP. As site work progresses the SWPPP will be modified routinely to reflect changing site conditions. The SWPPP will be reviewed monthly to ensure the content is current. Check all the management BMPs that apply at your site: Table 5 â€“ Management X Design the project to fit the existing topography, soils, and drainage patterns X Emphasize erosion control rather than sediment control X Minimize the extent and duration of the area exposed X Keep runoff velocities low X Retain sediment on-site X Thoroughly monitor site and maintain all ESC measures X Schedule major earthwork during the dry season Other (please describe) Optional: Fill out Table 6 by listing the BMP associated with specific construction activities. Identify the phase of the project (if applicable). To increase awareness of seasonal requirements, indicate if the activity falls within the wet or dry season. Table 6 â€“ BMP Implementation Schedule Phase of Construction Wet/Dry Stormwater BMPs Date Project Season [Insert construction [Insert BMP] [MM/DD/YYYY] [Insert activity] Season] Phase of Construction Wet/Dry Stormwater BMPs Date Project Season [Insert construction [Insert BMP] [MM/DD/YYYY] [Insert activity] Season] Element 13: Protect Low Impact Development (LID) BMPs (2.1.13) Describe LIDs. Permittees must protect all Bioretention and Rain Garden facilities from sedimentation through installation and maintenance of erosion and sediment control BMPs on portions of the site that drain into the Bioretention and/or Rain Garden facilities. Restore the facilities to their fully functioning condition if they accumulate sediment during construction. Restoring the facility must include removal of sediment and any sediment-laden Bioretention/Rain Garden soils, and replacing the removed soils with soils meeting the design specification. Permittees must maintain the infiltration capabilities of Bioretention and Rain Garden facilities by protecting against compaction by construction equipment and foot traffic. Protect completed lawn and landscaped areas from compaction due to construction equipment. Permittees must control erosion and avoid introducing sediment from surrounding land uses onto permeable pavements. Do not allow muddy construction equipment on the base material or pavement. Do not allow sediment-laden runoff onto permeable pavements. Permittees must clean permeable pavements fouled with sediments or no longer passing an initial infiltration test using local stormwater manual methodology or the manufacturerâ€™s procedures. Permittees must keep all heavy equipment off existing soils under LID facilities that have been excavated to final grade to retain the infiltration rate of the soils. Describe how you will protect LID facilities from sedimentation, protect soils from compaction, and maintain the infiltration capabilities. Describe how you will clean permeable pavements fouled with sediments. N/A as there are no biofiltration facilities onsite. Pollution Prevention Team (3.0) Table 7 â€“ Team Information Title Name(s) Phone Number Certified Erosion and Steve Rushton - Coast 425-315-4799 Sediment Control Lead (CESCL) Resident Engineer TBD Emergency Ecology Contact TBD 425-649-7000 Emergency Permittee/ Owner Tim Shoultz-SmartCAP 425-896-8561 Contact Non-Emergency Owner Same Contact Monitoring Personnel Ecology Regional Office [Insert Regional Office] [Insert General Number] Monitoring and Sampling Requirements (4.0) Monitoring includes visual inspection, sampling for water quality parameters of concern, and documentation of the inspection and sampling findings in a site log book. A site log book will be maintained for all on-site construction activities and will include: Â· A record of the implementation of the SWPPP and other permit requirements Â· Site inspections Â· Stormwater sampling data Create your own Site Inspection Form or use the Construction Stormwater Site Inspection Form found on Ecologyâ€™s website. https://www.ecology.wa.gov/Regulations-Permits/Permits- certifications/Stormwater-general-permits/Construction-stormwater-permit File a blank form under Appendix D. The site log book must be maintained on-site within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See CSWGP Special Condition S8 and Section 5 of this template. Complete the following paragraph for sites that discharge to impaired waterbodies for fine sediment, turbidity, phosphorus, or pH: The receiving waterbody, insert waterbody name, is impaired for: insert impairment. All stormwater and dewatering discharges from the site are subject to an effluent limit of 8.5 su for pH and/or 25 NTU for turbidity. Site Inspection (4.1) Site inspections will be conducted at least once every calendar week and within 24 hours following any discharge from the site. For sites that are temporarily stabilized and inactive, the required frequency is reduced to once per calendar month. The discharge point(s) are indicated on the Site Map (see Appendix A) and in accordance with the applicable requirements of the CSWGP. Stormwater Quality Sampling (4.2) Turbidity Sampling (4.2.1) Requirements include calibrated turbidity meter or transparency tube to sample site discharges for compliance with the CSWGP. Sampling will be conducted at all discharge points at least once per calendar week. Method for sampling turbidity: Check the analysis method you will use: Table 8 â€“ Turbidity Sampling Method Turbidity Meter/Turbidimeter (required for disturbances 5 acres or greater in size) Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size) The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency less than 33 centimeters. If the dischargeâ€™s turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to or greater than 6 cm, the following steps will be conducted: 1. Review the SWPPP for compliance with Special Condition S9. Make appropriate revisions within 7 days of the date the discharge exceeded the benchmark. 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. 3. Document BMP implementation and maintenance in the site log book. If the turbidity exceeds 250 NTU or the transparency is 6 cm or less at any time, the following steps will be conducted: 1. Telephone or submit an electronic report to the applicable Ecology Regionâ€™s Environmental Report Tracking System (ERTS) within 24 hours. https://www.ecology.wa.gov/About-us/Get-involved/Report-an-environmental-issue Â· Central Region (Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, Yakima): (509) 575-2490 Â· Eastern Region (Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman): (509) 329-3400 Â· Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish, Whatcom): (425) 649-7000 Â· Southwest Region (Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, Wahkiakum,): (360) 407-6300 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period 3. Document BMP implementation and maintenance in the site log book. 4. Continue to sample discharges daily until one of the following is true: Â· Turbidity is 25 NTU (or lower). Â· Transparency is 33 cm (or greater). Â· Compliance with the water quality limit for turbidity is achieved. o1 - 5 NTU over background turbidity, if background is less than 50 NTU o1% - 10% over background turbidity, if background is 50 NTU or greater Â· The discharge stops or is eliminated. pH Sampling (4.2.2) pH monitoring is required for â€œSignificant concrete workâ€ (i.e. greater than 1000 cubic yards poured concrete or recycled concrete over the life of the project).The use of engineered soils (soil amendments including but not limited to Portland cement-treated base [CTB], cement kiln dust [CKD] or fly ash) also requires pH monitoring. For significant concrete work, pH sampling will start the first day concrete is poured and continue until it is cured, typically three (3) weeks after the last pour. For engineered soils and recycled concrete, pH sampling begins when engineered soils or recycled concrete are first exposed to precipitation and continues until the area is fully stabilized. If the measured pH is 8.5 or greater, the following measures will be taken: 1. Prevent high pH water from entering storm sewer systems or surface water. 2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate technology such as carbon dioxide (CO2) sparging (liquid or dry ice). 3. Written approval will be obtained from Ecology prior to the use of chemical treatment other than CO2 sparging or dry ice. Method for sampling pH: Check the analysis method you will use: Table 8 â€“ pH Sampling Method pH meter pH test kit Wide range pH indicator paper Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies (5.0) 303(d) Listed Waterbodies (5.1) The 303(d) status is listed on the Water Quality Atlas: https://ecology.wa.gov/Water- Shorelines/Water-quality/Water-improvement/Assessment-of-state-waters-303d Circle the applicable answer, if necessary: Is the receiving water 303(d) (Category 5) listed for turbidity, fine sediment, phosphorus, or pH? Yes No List the impairment(s): [Insert text here] The receiving waterbody, insert waterbody name, is impaired for: insert impairment. All stormwater and dewatering discharges from the site are subject to an effluent limit of 8.5 su for pH and/or 25 NTU for turbidity. If yes, discharges must comply with applicable effluent limitations in S8.C and S8.D of the CSWGP. Describe the method(s) for 303(d) compliance: List and describe BMPs: [Insert text here] TMDL Waterbodies (5.2) Waste Load Allocation for CWSGP discharges: [Insert text here] Describe themethod(s) for TMDL compliance: List and describe BMPs: [Insert text here] Discharges to TMDL receiving waterbodies will meet in-stream water quality criteria at the point of discharge. The Construction Stormwater General Permit Proposed New Discharge to an Impaired Water Body form is included in Appendix F. Reporting and Record Keeping (6.0) Record Keeping (6.1) This section does not need to be filled out. It is a list of reminders for the permittee. Site Log Book (6.1.1) A site log book will be maintained for all on-site construction activities and will include: Â· A record of the implementation of the SWPPP and other permit requirements Â· Site inspections Â· Sample logs Records Retention (6.1.2) Records will be retained during the life of the project and for a minimum of three (3) years following the termination of permit coverage in accordance with Special Condition S5.C of the CSWGP. Permit documentation to be retained on-site: Â· CSWGP Â· Permit Coverage Letter Â· SWPPP Â· Site Log Book Permit documentation will be provided within 14 days of receipt of a written request from Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with Special Condition S5.G.2.b of the CSWGP. Updating the SWPPP (6.1.3) The SWPPP will be modified if: Â· Found ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. Â· There is a change in design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the State. The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine additional or modified BMPs are necessary for compliance. An updated timeline for BMP implementation will be prepared. Reporting (6.2) Discharge Monitoring Reports (6.2.1) Select and retain applicable paragraph. Cumulative soil disturbance is less than one (1) acre; therefore, Discharge Monitoring Reports (DMRs) will not be submitted to Ecology because water quality sampling is not being conducted at the site. Or Cumulative soil disturbance is one (1) acre or larger; therefore, Discharge Monitoring Reports (DMRs) will be submitted to Ecology monthly. If there was no discharge during a given monitoring period the DMR will be submitted as required, reporting â€œNo Dischargeâ€. The DMR due date is fifteen (15) days following the end of each calendar month. DMRs will be reported online through Ecologyâ€™s WQWebDMR System. To sign up for WQWebDMR go to: https://www.ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Water-quality- permits-guidance/WQWebPortal-guidance Notification of Noncompliance (6.2.2) If any of the terms and conditions of the permit is not met, and the resulting noncompliance may cause a threat to human health or the environment, the following actions will be taken: 1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable Regional office ERTS phone number (Regional office numbers listed below). 2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or correct the noncompliance. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Specific information to be included in the noncompliance report is found in Special Condition S5.F.3 of the CSWGP. Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6 cm or less, the Ecology Regional office will be notified by phone within 24hours of analysis as required by Special Condition S5.A of the CSWGP. Â· Central Region at (509) 575-2490 for Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, or Yakima County Â· Eastern Region at (509) 329-3400 for Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, or Whitman County Â· Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit, Snohomish, or Whatcom County Â· Southwest Region at (360) 407-6300 for Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, or Wahkiakum Include the following information: 1. Your name and / Phone number 2. Permit number 3. City / County of project 4. Sample results 5. Date / Time of call 6. Date / Time of sample 7. Project name In accordance with Special Condition S4.D.5.b of the CSWGP, the Ecology Regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water. Appendix/Glossary A. Site Map The site map must meet the requirements of Special Condition S9.E of the CSWGP B. BMP Detail Insert BMPs specification sheets here. Download BMPs from the Ecology Construction Stormwater website at: https://www.ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Stormwater- permittee-guidance-resources/Stormwater-manuals C. Correspondence Ecology EPA Local Government D. Site Inspection Form Create your own or download Ecologyâ€™s template: https://www.ecology.wa.gov/Regulations- Permits/Permits-certifications/Stormwater-general-permits/Construction-stormwater-permit E. Construction Stormwater General Permit (CSWGP) Download CSWGP: https://www.ecology.wa.gov/Regulations-Permits/Permits- certifications/Stormwater-general-permits/Construction-stormwater-permit F. 303(d) List Waterbodies / TMDL Waterbodies Information Proposed New Discharge to an Impaired Water Body form SWPPP Addendum addressing impairment G. Contaminated Site Information Administrative Order Sanitary Discharge Permit Soil Management Plan Soil and Groundwater Reports Maps and Figures Depicting Contamination H. Engineering Calculations TerraVista NW,LLC Appendix B Geotechnical Report November 15, 2019 Eric Scott, P.E., Principal TerraVista NW, LLC 3204 Smokey Point Drive, Suite 207 Arlington, WA 98223 Subject: Infiltration Feasibility & Mounding Assessment Proposed Commercial Site Improvements â€“ Trailer Boss 16523 Smokey Point Blvd, Arlington, Washington MTC Project No.: 19B335 Dear Mr. Scott: At your request, Materials Testing & Consulting, Inc. (MTC) has completed a targeted site characterization for infiltration assessment at the above referenced site proposed for stormwater improvements along with the planned site development. MTC understands the client intends to develop the project site with a new 36x44-foot office, a 40x54-foot shop, and pave the majority of the interior of the site to provide parking areas and trailer storage. The project will install decentralized stormwater improvements to accompany the expanded site use. The client and design engineer have requested this infiltration study be performed in support of stormwater facility planning and final design. In addition, the designer has asked for calculation of groundwater mounding using simplified methods to determine minimum vertical separation guidelines for the facilities from shallow seasonal high groundwater. Preliminary discussions indicate stormwater infiltration will be done by multiple linear infiltration trenches or buried cells at locations to be determined spread throughout the site interior, if feasible conditions allow. Design of these features is pending confirmation of site suitability for infiltration and determination of design rates and minimum separation requirements by this study. MTC has performed this infiltration assessment in accordance with site characterization guidelines presented in the Washington Department of Ecology Stormwater Management Manual for Western Washington, 2012/2014 edition (SMMWW, 2012/2014) as adopted by the City of Arlington. A summary of MTCâ€™s field findings, laboratory results, interpretations, and recommendations pertaining to the proposed infiltration facilities including long-term design rates are provided herein. In addition, the results of Cation Exchange Capacity (CEC) and Organic Content (OC) analyses conducted on representative soil samples from the potential infiltration areas are attached at the end of this report for consideration in stormwater treatment if required. Environmental â— Geotechnical Engineering â— Special Inspecon â— Non-Destructive Testing â— Materials Tesng Burlington|Olympia|Bellingham|Silverdale|Tukwila 360.755.1990 www.mtc-inc.net Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Site Exploration and Assessment Methodology: On October 16, 2019, an MTC Project Geologist visited the site to observe and direct excavation of test pits for infiltration assessment and to collect soil samples for laboratory gradation analysis. MTC personnel observed excavation of test pits at six locations as determined on site by an MTC Geologist based on the proposed project layout, and space accessible for work at the time of the visit. The project site contains an existing business in a rectangular area (northwest portion) and will expand into a second rectangular area (southeast) oriented perpendicular to the first, with a small central area connecting them (see map). The northwestern portion of the site was generally inaccessible due to trailer staging and prevalent utilities, however MTC was provided a previous soils report from the site that included explorations in this area indicating similar conditions throughout the site. Test Pits TP-1 through TP-4 were excavated in the undeveloped southeastern part of the site. Locations were in the south-central, southeast, northeast, and northwest areas of the southeast lot, respectively. TP- 5 was sited in the south-central connecting area between the two lots. TP-6 was located in the south- central portion of the northwestern in-use lot. The previous soils report included two test pits in each of the two lots. An abandoned â€˜wet wellâ€™ was also observed on site just west of TP-6 where there had been a historically demolished residence. Explorations were field located by MTC and arranged for optimum coverage of potential areas for infiltration design. Backhoe test pits were completed to termination depths ranging from approximately 5.3 to 7.7 feet below present grade (BPG). Explorations were terminated upon sidewall caving due to groundwater inundation. Explorations were monitored by MTC personnel, who examined and classified the materials encountered in accordance with the Unified Soil Classification System (USCS) and ASTM D2487, obtained representative soil samples, and recorded pertinent information including soil stratigraphy, soil engineering characteristics, and indications of groundwater occurrences as well as visual evidence of seasonal groundwater. Upon completion, test pits were backfilled with soil tailings. Grab soil samples were collected from representative soil horizons during test pit excavation and at potential infiltration depths, as depicted on the attached logs. All samples were placed in plastic bags to limit moisture loss, labeled, and returned to MTCâ€™s laboratory for analysis and storage. Samples will be retained for a minimum of 90 days from the date of collection. A location and vicinity map are provided in Figure 1, Appendix A1. A site plan with approximate test locations is provided in Figure 2, Appendix A2. Attached in Appendix B are photos of the site and explorations in progress. Exploration logs are presented in Appendix C, with a USCS classification chart provided as Figure 3. Results of laboratory analyses on soil samples collected during the field visit are attached in Appendix D. 2 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Site Conditions: The project site is located in Arlington, Washington, east of the I-5 corridor on the east side of Smokey Point Boulevard, and roughly Â¼-mile south of SR 531. The property is located within a generally commercialized area, though it is neighbored to the south by a remaining single-family residence with a small yard. The west and north property boundaries are made up of Smokey Point Blvd and 166th Place NE, respectively. A moderately-sized power substation is located directly to the east and north, against the northwest and southeast areas respectively, and to the east of that is a preschool complex. The large site to the east of the southeast parcel is partially undeveloped. The site interior is approximately flat and is divided into two parcels in differing stages of development. Both areas have been cleared of all major vegetation. The northwest & central area contains chipped gravel throughout and is currently in use as a parking and staging area for Trailer Boss merchandise. Other minor structures observed in the northwest area include a small concrete parking pad to the northeast, a temporary office trailer to the east, an abandoned residential â€˜wet wellâ€™ in the southwest, and temporary lighting throughout the interior. The southeast area is generally undeveloped, though it has been graded, which apparently removed topsoil and the majority of organic material in preparation for the proposed development. Subsurface Soil Conditions: Subsurface soils were observed and catalogued during test pit excavations. This section summarizes our general understanding of site soil conditions gained from completing field explorations and laboratory analyses. We also reviewed prior report information provided by the client, as discussed below. The site exhibited various surface conditions including gravel over reworked native fill in the northwest area, and native alluvium exposed after topsoil stripping in the southeast. No topsoil was observed, though some organic material was seen in TP-5 and TP-6 within reworked fill materials. No obvious fill was observed in the southeastern area, indicating that grading to date has only included material removal. The upper undisturbed native soil profile beginning at the surface or by 1.25 to 1.5 feet BPG was composed of sand with silt to silty sand. Fines content within the upper unit was visually estimated to range from 10 to 15% and locally up to about 30%. Soils at TP-4 through TP-6 exhibited some local cohesion and blocky habit in the upper 1.5 to 3.0 feet, which correlated to a relatively higher fines content. A similar horizon, approximately 6 inches thick was observed at around 5.5 feet only in TP-6. Below the upper deposits, underlying material generally consisted of sand to sand with gravel & coarsening downward. The lower unit had minor to trace fines, and was moist to wet with depth. The upper boundary varied between test pits, though was generally at around 3 to 4 feet BPG. The outliers were at TP-1, where it was encountered at 2.2 feet, and at TP-6 where it was reached at 3.5 feet BPG. 3 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Previous work by others (Geotech Consultants, Inc.; 2016) was reviewed for general coverage and understanding of the full site conditions. The GCI report describes finding similar conditions of an upper silty sand and lower sand at all of four test pits. The interface between the units was also variable by location. Clean sand was contacted typically between 3 to 4 feet BPG, with soils above coarsening with depth. TP-1 was done in an area inaccessible during our field work, at the north-central part of the west lot. Their logging of silty sand to sand with silt to about 3.5 feet BPG corresponds closely with the closest MTC test pit (TP-6) further to the south. By comparison with the GCI results, we anticipate conditions to be widely similar throughout the site. Geologic Literature: The Geologic Map of the Arlington West 7.5 minute quadrangle, published by the US Geologic Survey depicts the site as within an area of Quaternary Recessional Outwash (Marysville Sand Member-Qvrm) based on 1:24,000-scale mapping. Qvrm deposits are associated with the meltwaters of the receding Vashon glacier. These deposits are typically described as stratified or massive, clean outwash sand with local areas of fine gravel, silt, and clay. In our experience, the uppermost deposits and cover soils of this unit are commonly composed of silty sand grading to coarse sand with depth. Shallow subsurface conditions at the site are mapped by the USDA NRCS Web Soil Survey as Custer Fine Sandy Loam (#13). Custer Fine Sandy Loam is described as deposited on outwash plains from a parent material of glacial outwash. Typical profile includes fine sandy loam to 9 inches, underlain by sand to past 60 inches. Where undrained, the soil is listed as poorly drained with a moderately high capacity to transmit water through its most limiting layer (upper conditions). Depth to the seasonal high- water table is listed at 0 to 12 inches. It is a member of Hydrologic Soil Group C/D. Native soil conditions encountered in the field (below surface fills, if present) are interpreted to consist of outwash sand deposits, ranging commonly from silty sand to sand with silt at upper levels with predominantly coarse-grained units beginning on average around 4 feet depth. Soils observed in field explorations generally correspond with mapped geology. Soils also broadly correspond with soil survey data, although the groundwater conditions documented by MTC and previous work differ from the described â€œundrainedâ€ conditions per the NRCS. Surface and Subsurface Water Conditions: The project site is roughly 0.4 miles northeast of Gissberg Twin Lakes, and roughly the same distance from small tributaries of Quilceda Creek to the south and east. The site is also approximately 3.2 miles south of the Stillaguamish River. No other major surface water features are present in the project area. 4 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 A prevalent groundwater table was encountered at the time of our field investigation in the fall season. All explorations also contained free water seepage at similar depths to the water table. After some open time for stabilization, groundwater was measured at around 5 feet depth in TP-1 and TP-2. Water levels were recorded between 6 to 7 feet depth in Test Pits TP-3 through TP-6 and within the nearby â€˜wet wellâ€™. Groundwater was most shallow in the southeast part of the site compared to surface grade, and relatively deeper to the west. This appears to be at least partly a function of relative surface grades between the two areas. Given the timeframe of the explorations in the early fall season following moderately high levels of precipitation (as well as precipitation during field work), conditions are expected to be seasonally elevated from base dry season levels, though not at fully developed wet season groundwater levels. Peak seasonal groundwater levels are normally established by mid-winter and persist through early spring. We observed for soil mottling and oxidation staining patterns to estimate seasonal high groundwater levels anticipated for the winter season. Shallow scattered mottling observed in the upper unit and along the top portion of the underlying sand is interpreted to be due to downward transmission of meteoric surface waters, and not a result of full seasonal saturation. Scattered mottling was observed throughout the upper deposits at all locations explored. No heavy linear feature, such as heavy oxidation banding, was seen that would strongly suggest a seasonal high water level. The absence of such evidence is not uncommon in predominantly coarse-grained soils. We did note the onset of low-chroma coloration within the lower sand unit before end depths suggesting groundwater inundation above the elevations observed. GCIâ€™s explorations were performed in late March of 2016, a year of notably higher rainfall. Their findings most likely reflect a stabilized high wet season level (not necessarily true peak but at least sustained). GCI recorded static groundwater levels of 3 to 5 feet BPG. Similar to our observations, the groundwater level was higher relative to surface grade at the southeast lot (4.0 and 3.0 feet BPG), and marginally deeper at the northwest lot (4.0 and 5.0 feet BPG). While MTC cannot certify the accuracy of the work by others, the recorded levels appear to correspond well with our observations of soil coloration. MTCâ€™s current scope of investigation did not include direct observation and determination of seasonal groundwater variations, or conclusive measurement of groundwater elevations by establishment of monitoring wells. The conditions on field logs are valid only for the date of exploration. Estimated seasonal high groundwater conditions based on indirect mottling evidence shall be understood as interpreted rather than a statement of fact. At the request of the client, MTC can perform additional site characterization involving the monitoring of seasonal groundwater elevations if required for final design and approval. 5 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Infiltration Assessment & Commentary: Gradation Analysis Method & Results During test pit excavations, MTC collected representative samples of soils among native strata at and below potential infiltration depths. No target depths or locations were set prior to field work. Based on project discussions, test pit observations, and the GCI work, we assume infiltration depths will be shallow and via linear infiltration trenches. MTC understands that the final locations, sizes, and depths of the infiltration facilities will be refined following the results of this study. Laboratory gradation analyses were completed via sieve tests for general rate determination to supplement field observations. Results of laboratory testing are summarized below. Laboratory results were interpreted to hydraulic conductivity (Ksat) values in accordance with methods of the Washington State Department of Ecology Stormwater Management Manual for Western Washington (SMMWW), 2012/2014. Standard correction factors were applied as noted in the reference documents. Data and Ksat values are summarized in Table 1. Gradation results were applied to the Massmann (2003) equation (1) to calculate Ksat representing the initial saturated hydraulic conductivity, as described in the 2012 DOE SMMWW Volume III 3.3.6.3. (1) log10(Ksat) = -1.57 + 1.90*D10 + 0.015*D60 - 0.013*D90 - 2.08*ff Table 2 reports for each sample the input laboratory values and calculated Ksat. Corrected Ksat values presented below are a product of the initial Ksat and correction factor CFT. For a generalized design situation, we have applied an average site variability factor of CFv = 0.5 along with typical values of CFt = 0.4 (for the Grain Size Method) and CFm = 0.9 (assuming standard influent control). (2) CFT = CFv x CFt x CFm = 0.5 x 0.4 x 0.9 = 0.18 Table 1. Results of Massmann Analysis Depth Ff Ksat Corrected Ksat TP # USCS D10 D60 D90 (BPG) (%) (inches/hour) (inches/hour) 2 2 SP-SM 0.12 0.578 1.785 6.9 44.81 8.07 2 5.5 SP 0.172 0.719 1.93 1.7 72.21 13.00 4 3 SP-SM 0.092 0.299 0.408 7.3 40.14 7.23 5 4 SP 0.152 0.358 1.372 1.5 67.08 12.07 6 2 SM 0.026 0.211 0.404 28.8 10.71 1.93 6 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Facility Design Discussion and Rates MTC understands the stormwater system will undergo further design pending the results of this assessment to confirm general feasibility of infiltration, design rates, and viable minimum separation to groundwater. Based on discussions with the designer, on-site stormwater management is anticipated to consist of a series of shallow, distributed linear infiltration trenches beneath or at the perimeter of paved areas. Locations and depths are to be determined. Grain size analysis methods based on SMMWW 2012/2014 standard calculation criteria yielded Corrected Ksat values for native alluvial soils in the upper 6 feet of the subsurface profile ranging from about 2 to 13 inches per hour. Rates should be divided into two sections for design purposes based on soil stratigraphy encountered. The upper silty sand to sand with silt (where tested) yielded Ksat values of as low as about 2 inches per hour (where fines content was elevated up to 25% to 30% maximum) and higher values of 7 to 8 inches per hour where fines contents were below 10%. These rates were derived from samples collected at 2 to 3 feet BPG. The sample from 2.0 feet BPG in TP-6 had a fines content approaching 30%, which is interpreted to be representative of the finer-grained end of the spectrum for the shallow unit where observed. For general site-wide application with locations and depths to be determined, we recommend applying a maximum design Ksat value of 2.0 inches/hour. Given the range of shallow conditions observed, actual infiltration rates are expected to be equal or better than this value at a given location. Use of a relatively low rate will also help to minimize potential for groundwater mounding. Rates derived from samples within the lower sand unit at depths of 4.0 and 5.5 feet BPG were in the realm of 12 to 13 inches per hour. While the transmission potential is greater with depth, the limiting factor of seasonal high groundwater may preclude placement of systems at that level. If specific design locations and dimensions are able to maintain minimum vertical separations as discussed below, a Ksat value of up to 10 inches/hour may be used for infiltration into the clean sand unit. For systems placed at greater depths, it is likely that wet season monitoring and explorations at final design locations will be required to closely dial in depths for final design and approval. The derived rates are meant to provide a general characterization of shallow subsurface transmission potential for the designerâ€™s use, but are not necessarily intended to be applied as a final infiltration rate for facilities of an undetermined location and depth or for systems of a larger size/volume than anticipated at this time. The inherent site limitation of depth to seasonal groundwater must be accounted for in design. We recommend the design rate be applied conservatively, and systems should maintain as much vertical separation as possible. The facility designer should also review assumed correction factors per reference literature to ensure applicability with the proposed development, level of anticipated 7 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 controls, and long-term maintenance plan. The designer may make reasonable adjustments to correction factors and resulting design values based on these criteria to ensure design and operational intent is met. The project may be eligible for an increase in design rate if Pilot Infiltration Testing (PIT) methods are conducted at design locations and depths, which are considered generally more reliable as a confirmation of actual field conditions and therefore can be applied less conservatively. The client can also elect to conduct additional sampling and rate analysis at actual facility locations for adjustment of sizing on a per-location basis. It is our opinion that grain size analysis methods should be suitable for general design use of the proposed systems at this site, in accordance with DoE SMMWW 2012/2014 requirements. The native soils are not considered to be compacted by prior development (aside from surface fills anticipated to be removed below facilities) or consolidated by glacial ice, and were observed to be relatively uniform with no significant cementation or local variations, except for those accounted for as discussed above. At request of the client, MTC can provide additional services for completing PITs or location-specific sampling to verify the final stormwater design. Treatment Suitability MTC subcontracted Cation Exchange Coefficient (CEC) and Organic Content (OC) testing of representative samples of the shallow native deposits considered for infiltration facilities. Soil samples yielded CEC values between 2.6 to 4.7 milliequivalents per 100 grams of soil (meq/100g). Organic content testing recorded between 1.6% and 3.4% organic matter by weight. Table 2 below shows the results from the laboratory testing. In our experience with similar soils, these values appear typical for the soil types encountered and their respective fines and organic contents observed. Table 2. Results of Cation Exchange Coefficient and Organic Content Analysis Depth Organic Content CEC TP # USCS (BPG) (% by weight) (meq/100g) 2 2.0 SP-SM 2.0 2.6 4 3.0 SP-SM 1.6 2.2 6 2.0 SM 3.4 4.7 The Department of Ecology 2012/2014 SMMWW, Volume III, Section 3.3.7 addresses minimum requirements for treatment soils under Site Suitability Criteria. According to SSC-6, native soils with CEC values of at least 5 meq/100g and >1% organic content by weight are considered suitable as treatment media without modification. The addition of soil amendments or the import of treatment- specific soil media may be used to achieve a higher CEC and produce a soil more suitable for treatment if required for design where native soils are deficient. In the case of this site, organic contents are above 8 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 target value (1% minimum) within the upper native soils. However, CEC values recorded are consistently in the range of about 2 to 4 meq/100g, below the minimum treatment threshold. CEC and OC tests were not completed on the lower sand unit. Based on our experience, clean sand soils typically do not meet the minimum standards for treatment without amendment. Therefore, if treatment is required as part of this design, soil amendment or treatment media will be necessary to meet treatment standards. Minimum depth for treatment-suitable soils is cited as 18 inches per the DoE SMMWW. If soils are amended or imported treatment media is installed, the LTIR of the facility must be adjusted accordingly by the designer if these modifications will negatively affect the infiltration rate cited above. Mounding Analysis Methods & Results: At request of the designer, MTC has completed a simplified mounding calculation employing the methods of Zomorodi (1991, 2005) for the anticipated stormwater infiltration system. The referenced method is applicable to relatively uniform soil and groundwater conditions, and use of small-scale linear features which have a length many times the width. In that case, the mound can be assessed in two dimensions, with the facility width being the governing factor along with underlying soil transmissivity (saturated Hydraulic Conductivity). The system is undergoing design at this time. Per project discussions, we anticipate the system will consist of decentralized trenches filled with gravel and supplied by a level perforated pipe or similar distribution system to control application over the infiltration area. From past experience, we assume a distribution pipe will be placed with its base at least 4 to 6 inches above the bottom of the gravel fill. In a practical sense, system failure may be considered as the point at which groundwater level meets the base of the pipe and impedes stormwater delivery. However, for the purposes of our analysis MTC considers maximum allowable mounding to be equal to the base of the gravel bed feature. Ksat Determination MTC performed the following mounding calculations using the simplified solutions for recharge strip mounding derived by Zomorodi (1991, 2005). The purpose was to verify minimum design vertical separation needed from seasonal high groundwater conditions for the anticipated style of facilities. Preparing for the calculations requires determining saturated hydraulic conductivities (Ksat) for representative soil conditions. Ksat values were adopted from the current study laboratory testing and gradation method calculations described above: Upper Unit Silty Sand, Sand With Silt (SM, SP-SM) Ksat = 21.4 feet/day Lower Unit Sand, low fines content (SP) Ksat = 134.2 feet/day 9 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Mounding Calculations In a simplified case, mounding potential for infiltrating water above a water table or restrictive horizon (h) is a function of recharge rate (i), horizontal Ksat (k), and recharge facility width (w) per equation (3): (3) h = (0.86 * i * w) / (k â€“ i) To address a maximum input scenario, the recharge rate (i) was set equal to the design infiltration rate per soil type (recommended values above). Conductivity (k) was applied using representative Ksat values listed above. Width of the facility was varied to determine a balance between practical vertical separation and likely optimal width for the anticipated system style. Mounding inputs and final results are tabulated in Table 3: TABLE 3. Summary of Mounding Analysis Results Hydraulic Soil Recharge Gravel Bed Maximum Mound Mound Height Conductivity Condition (i) Width (w) Central Height (Hc) at Edge (He) (Ksat = k) SM 21.4 4.0 5 0.99 0.64 SP 134.2 20.0 5 0.75 0.47 NOTE: All dimensions in feet. All rates in feet/day. Discussion of Results According to the results of this analysis, mounding will occur to some extent under the facility while stormwater infiltrates vertically and spreads laterally. In our experience with similar trench systems and shallow groundwater, a minimum separation of 1.0 feet can be viable if site soil conditions allow. In this case, the site conditions are generally well suited for infiltration. An optimum maximum width of 5.0 feet for trench features is recommended to minimize mounding potential to about 1 foot or less below the center of the trench. The mound also dissipates laterally from the center of the facility, with heights at the edges of the bed being reduced by over one-third. By about 10 feet from the facility center line, mounding effects on latent groundwater level are negligible. We also note, as discussed above, that shallow soils will typically be more transmissive than the most conservative value used for Ksat determination and mounding calculations. Therefore, actual mounding is anticipated to be less on average than what is noted in Table 3. By using the other Ksat values gained from shallow soil laboratory analysis and assuming a 5-foot trench width, we tabulate a lower mound height of about 0.3 feet. 10 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Closing Remarks: MTC recommends that we be contacted to review proposed stormwater facility design, site preparation plans, and project specifications, to ensure they are consistent with the intent of the recommendations provided herein. In addition, MTC recommends that we be contacted for construction phase testing, observation, and engineering consultation services as may be needed. Such services may include but are not limited to earthwork support consulting, subgrade bearing and infiltration verifications, laboratory materials analysis, and special inspections if required. Mr. Scott, we trust this report presents the information you require. If you have questions, please do not hesitate to call. Respectfully Submitted; 11-15-2019 John R. Gillaspy, L.E.G. Mike Furman, G.I.T. NW Region Geotechnical Division Manager Project Geologist Attached: Limitations and Use of this Report Appendix A1. Location and Vicinity Map Appendix A2. Site Plan with Test Locations Appendix B. Photos of Site Exploration Appendix C. Exploration Logs Appendix D. Laboratory Results 11 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Limitations and Use of This Report Recommendations contained in this report are based on our understanding of the proposed development and construction activities, our field observations and explorations, and our laboratory test results. It is possible that soil and groundwater conditions could vary and differ between or beyond the points explored. If soil or groundwater conditions are encountered during construction that vary or differ from those described herein, we should be notified immediately in order to review and provide supplemental recommendations. If the scope of the proposed construction, including the proposed loads or structural locations, changes from that described in this report, we should be notified to review and provide supplemental recommendations. We have prepared this report in substantial accordance with the generally accepted geotechnical engineering practice as it exists in the site area at the time of our study. No warranty, expressed or implied, is made. The recommendations provided in this report assume that an adequate program of tests and observations will be conducted by MTC during the construction phase in order to evaluate compliance with our recommendations. This report may be used only by the Client and their design consultants and only for the purposes stated within a reasonable time from its issuance, but in no event later than 18 months from the date of the report. It is the Client's responsibility to ensure that the Designer, Contractor, Subcontractors, etc. are made aware of this report in its entirety. Note that if another firm assumes Geotechnical Engineer of Record responsibilities, they need to review this report and either concur with the findings, conclusions, and recommendations or provide alternate findings, conclusions and recommendation under the guidance of a professional engineer registered in the State of Washington. Land or facility use, on- and off-site conditions, regulations, or other factors may change over time, and additional work may be required. Based on the intended use of the report, MTC may recommend that additional work be performed and that an updated report be issued. Non-compliance with any of these requirements by the Client or anyone else will release MTC from any liability resulting from the use of this report. The Client, the design consultants, and any unauthorized party, agree to defend, indemnify, and hold harmless MTC from any claim or liability associated with such unauthorized use or non- compliance. We recommend that MTC be given the opportunity to review the final project plans and specifications to evaluate if our recommendations have been properly interpreted. We assume no responsibility for misinterpretation of our recommendations. The scope of work for this subsurface exploration and geotechnical report did not include environmental assessments or evaluations regarding the presence or absence of wetlands or hazardous substances in the soil, surface water, or groundwater at this site. 12 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix A1. Location and Vicinity Map Site Vicinity Site Location Maps Source: Google Imagery 2019 Materials Testing & Consulting, Site Location & Vicinity FIGURE Inc. Trailer Boss Infiltration Study 777 Chrysler Drive 16523 Smokey Point Blvd 1 Burlington, WA 98233 Arlington, WA 13 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix A2. Site Plan with Test Locations 1 2 TP-4 TP-3 3 TP-6 TP-5 4 TP-2 0 90 MTC 2019 Test Pit Location (approximate) TP-1 Previous Explorations (GCI, 3-24-2016) SCALE (FEET) 1 inch ~ 90 feet Materials Testing & Consulting, Inc. Base Map: Paving Plan â€“ Trailer Boss Site Site Plan with Test Locations FIGURE By: TerraVista NW 8-5-2019 777 Chrysler Drive Trailer Boss Infiltration Study Overlay by MTC: 10-29-2019 2 Burlington, WA 98233 NOT INTENDED FOR CONSTRUCTION 16523 Smokey Point Blvd NOT TO SCALE - Shown is Approximate Arlington, WA 14 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix B. Photos of Site Exploration TP-1 Photo A: Overview of northwestern portion of project site, looking north from the south-central end of proposed improvement area. Note prevalent impediments among middle and north end. Photo B: Overview of southeastern portion of project site, looking southeast from the central transition area of property. No vegetation remains. 15 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 TP-1 Photo C: TP-1 excavation in southeast area. Soil is generally sandy but coarsens with depth. Note mottling in upper subsurface that fades at around 3 feet depth. Groundwater at 5.0 feet BPG. TP-6 Photo D: TP-6 excavation in southwest area of project site. Organic material and disturbed soils observed below imported chipped surfacing to 1.5 feet BPG. Shallow native soils were silty sand, with mottling throughout. Gray sand below about 3.5 feet BPG. Groundwater at 7.0 feet BPG. 16 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix C. Exploration Logs UNIFIED SOIL CLASSIFICATION SYSTEM - USCS LOG SYMBOLS MAJOR DIVISIONS USCS SYMBOL TYPICAL DESCRIPTIONS SAMPLES GW WELL-GRADED GRAVEL SPT Standard Penetration Test < 5% FINES GRAVEL CLEAN GRAVEL Grab or bulk WITH LESS THAN POORLY-GRADED GRAVEL Gravel > Sand 5% FINES GP California or D&M (3.0" OD) < 5% FINES (More than half Shelby Tube of coarse fraction SILTY GRAVEL is larger than GM COARSE GRAVEL > 12% FINES (SILT > CLAY) #4 sieve) GRAINED WITH OVER WATER TABLE SOILS 12% FINES CLAYEY GRAVEL GC Groundwater Level > 12% FINES (CLAY > SILT) (where first encountered) More than half of Groundwater Level material is larger WELL-GRADED SAND CLEAN SAND SW (measured after completion) than the #200 < 5% FINES WITH LESS THAN Perched Groundwater Level sieve SAND 5% FINES (during exploration) SP POORLY-GRADED SAND Silt and / or Clay < 5% FINES Sand > Gravel content as (More than half specified SILTY SAND of coarse fraction SM > 12% FINES (SILT > CLAY) DENSITY: COARSE-GRAINED SOIL is smaller than SAND WITH the #4 sieve) OVER 12% FINES APPARENT SPT SC CLAYEY SAND DENSITY Blows / foot > 12% FINES (CLAY > SILT) Very Loose < 5 INORGANIC SILT; LEAN, LOW PLASTICITY Loose 5 - 10 ML SILT. Medium Dense 11 - 30 Dense 31 - 50 SILT AND CLAY INORGANIC CLAY; LEAN, LOW PLASTICITY Very Dense > 50 FINE CL GRAINED Lean, low to medium plasticity CLAY SOILS (Liquid limit less than 50) ORGANIC SILT & ORGANIC CLAY, OL LEAN, LOW PLASTICITY, DENSITY: FINE-GRAINED SOIL RETAINS VERY HIGH MOISTURE More than half of material is fines INORGANIC SILT, HIGH PLASTICITY, APPARENT SPT (smaller than the MH DENSITY Blows / foot FAT SILT, MAY BE MICACEOUS #200 sieve) SILT AND CLAY Very Soft < 3 CH INORGANIC CLAY, HIGH PLASTICITY, Soft 3 - 4 Sand and / or FAT CLAY Fat, high plasticity Medium Stiff 5 - 8 Gravel content as specified in log (Liquid limit greater than 50) ORGANIC CLAY & ORGANIC SILT Stiff 9 - 15 OH FAT, HIGH PLASTICITY, Very Stiff 16 - 30 RETAINS VERY HIGH MOISTURE Hard > 30 PEAT, HUMUS, SWAMP SOILS, HIGHLY ORGANIC SOILS PT PREDOMINANTLY ORGANIC CONTENT NOTES STRATIGRAPHIC CONTACT USCS evaluated by field observations. Laboratory analyses used when conducted. (approximated by field identification) Poorly-Graded (GP or SP) indicate not an equal content of every grain size subgroup. Distinct stratigraphic Calculated using 10%, 30%, and 60% grain size. contact between soil strata Combination names (e.g. SP-SM Poorly-Graded SAND with silt, represent fines Gradual change between soil strata content between 5% and 12%. Fines content is dominantly either clay (c) or silt (m). Approximate location of A soil description of "with sand" or "with gravel" represents greater than 15% coarse stratigraphic change material, and dominant coarse soil is the one specified. DEFINITIONS OF SOIL FRACTIONS MODIFIERS (see USCS and Notes) SOIL COMPONENT GRAIN SIZE (inch) GRAIN SIZE (metric) DESCRIPTION % Boulder > 12 in. > 305 mm Trace Cobbles 3 in. to 12 in. 75 mm to 305 mm <5% Gravel 3 in. to # 4 sieve 75 mm to 4.75 mm With Clay, With Silt 5 - 12% Fines Coarse Gravel 3 in. to 3/4 in. 75 mm to 19 mm Clayey, Silty >12% Fines Fine Gravel 3/4 in. to # 4 19 mm to 4.75 mm With Sand, With Gravel 15 - 30% Coarse Sand # 4 to # 200 4.75 mm to 0.075 mm Sandy, Gravelly >30% Coarse Coarse # 4 to # 10 4.75 mm to 2 mm Medium # 10 to # 40 2 mm to 0.425 mm Fine # 40 to #200 0.425 mm to 0.075 mm C o p y r ig h t 2 0 1 9 M T C I n c . 3 / 4 / 2 0 1 9 Fines (Silt or Clay) < #200 sieve < 0.075 mm Materials Testing & Consulting, Inc. Exploration Log Key FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 3 Arlington, WA 17 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-1 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : S Center of East lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 SAND WITH SILT to SILTY SAND, trace gravel up to 1/4", fine & medium-grained sand, moist, loose to medium dense, contains moderate organics including 1/2" roots. Light BROWN to TAN-GRAY with light to moderate mottling throughout. 1 SP-SM Local heavy mottling at ~1.6'. 2 SAND WITH GRAVEL, trace silt, moist, loose to medium dense, minor organics including 0.25" roots, gravel up to 1/2" with medium & coarse-grained sand. Medium GRAY. 3 SP 4 Increase in gravel content observed at 4' BPG. 5 Heavy seepage observed at 5' BPG. T.D. @ ~5.3' due to sidewall caving Stabilized water level observed at 5.0' BPG. 6 7 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-1.bor 18 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-2 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : SE corner of E lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 SAND WITH SILT, some gravel up to 1/4", fine & medium-grained sand, moist, loose to medium dense, contains moderate organics including 1/2" roots. Light BROWN to TAN-GRAY with light to moderate mottling throughout, local heavy oxidation staining. 1 SP-SM 2 CEC: 2.6 meq/100 OC: 2% 6.9% 9.1% 3 SAND WITH GRAVEL, trace SILT, gravel up to 1/2", medium & coarse-grained sand, moist, loose to medium dense, contains trace organics and 1/2" roots. Medium GRAY. Increase in gravel content observed at 3.5' BPG. 4 Becomes wet at 4.0' BPG. SP Seepage observed at 4.8' BPG. 5 1.7% 25.9% 6 T.D. @ ~6.2' due to sidewall caving Stabilized water level observed at 5.0' BPG. 7 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-2.bor 19 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-3 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : NE area of E lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 SAND WITH SILT AND GRAVEL, gravel up to 1/4", moist, loose to medium dense, contains moderate organics and 1/2" roots. Light BROWN to TAN-GRAY with light to moderate mottling throughout. 1 Local heavy mottling at ~1.0'. Sand observed to coarsen with depth. 2 SP-SM 3 4 SAND WITH GRAVEL, trace silt, moist to wet with depth, loose to medium dense, minor organics including 1/2" roots, gravel up to 1/2" with medium & coarse-grained sand. Medium GRAY. 5 SP Increase in gravel content observed at 5.5' BPG. Becomes wet at 5.5' BPG. 6 Heavy seepage observed at 6.0' BPG. 7 T.D. @ ~7.0' due to sidewall caving Stabilized water level observed at 5.8' BPG. 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-3.bor 20 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-4 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : NW/Ctr of E lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 SAND WITH SILT to SILTY SAND, trace gravel up to 1/4", fine & medium-grained sand, moist, loose to medium dense, contains moderate organics including 1/2" roots. Light BROWN to TAN-GRAY with moderate mottling becoming lighter with depth. 1 Excavated soils exhibit some cohesion and blocky habit at 1.5' BPG. SP-SM 2 3 CEC: 2.2 meq/100 OC: 1.6% 7.3% 8.0% SAND WITH GRAVEL, trace silt, moist to wet with depth, loose to medium dense, minor 4 organics including 1/2" roots, gravel up to 1" with medium & coarse-grained sand. Medium GRAY with faint mottling. 5 SP 6 Becomes wet at 6.7' BPG. 7 Seepage observed at 7.0' BPG. SP-SM SAND WITH SILT to SILTY SAND, fine-grained sand, wet, medium dense, exhibits some cohesion and blocky habit when excavated. Medium GRAY. 8 T.D. @ ~7.7' due to sidewall caving Stabilized water level observed at 7.0' BPG. 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-4.bor 21 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-5 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : South Central transition area (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 GW Chipped GRAVEL Imported Surfacing Material SAND WITH SILT, moist, loose, contains organics including carbonized wood and roots up to 1/2" thick. Light BROWN to dark REDDISH BROWN, variable. SP-SM Apparent reworked native fill 1 SILTY SAND, some gravel, moist, loose to medium dense, contains moderate organics including some 1/2" roots. Light BROWN to TAN-GRAY with moderate mottling becoming lighter with depth. 2 Excavated soils exhibit some cohesion and blocky habit at 2.0' BPG. SM 3 SAND WITH GRAVEL, trace silt, moist to wet with depth, medium dense, minor organics 4 including 1/2" roots, gravel up to 1" with medium & coarse-grained sand. Medium GRAY with faint mottling. 1.5% 30.7% 5 Gravel content observed to increase with depth. SP 6 Seepage observed at 6.5' BPG. 7 T.D. @ ~7.5' due to sidewall caving Stabilized water level observed at 6.5' BPG. 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-5.bor 22 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-6 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : South Central part of W lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 GW Chipped GRAVEL, Imported Surfacing Material SAND WITH SILT, moist, loose, contains organics including carbonized wood and roots up to 1/2" thick. Light BROWN to dark REDDISH BROWN, variable. SP-SM Apparent reworked native fill 1 SILTY SAND, some gravel, moist, loose to medium dense, contains moderate organics including some 1/2" roots. Light BROWN to TAN-GRAY with moderate mottling becoming lighter with depth. 2 CEC: 4.7 meq/100 OC:3.4% 28.8% 25.9% SM 3 Excavated soils exhibit some cohesion and blocky habit at 3.0' BPG. SAND, trace gravel and silt, moist to wet with depth, medium dense, minor organics including 1/2" roots, gravel up to 1" with medium & coarse-grained sand. Medium GRAY with faint mottling. 4 SP 5 SILTY SAND, fine-grained sand, wet, medium dense, blocky habit. Medium GRAY. 25.1% SM SAND, trace gravel and silt, wet, medium dense, minor organics including 1/2" roots, gravel up to 1" with medium & coarse-grained sand. Medium GRAY with faint mottling. 6 SP Seepage observed between 6.5 & 7.0' BPG. 7 T.D. @ ~7.5' due to sidewall caving Stabilized water level observed at 7.0' BPG. 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-6.bor 23 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix D. Laboratory Results Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SP-SM, Poorly graded Sand with Silt Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-2 @ 2.0' Tested By: A. Eifrig brown Sample#: B19-1012 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.054 mm % Gravel = 3.5% Coeff. of Curvature, CC = 0.99 Specifications D(10) = 0.120 mm % Sand = 89.6% Coeff. of Uniformity, CU = 4.80 No Specs D(15) = 0.169 mm % Silt & Clay = 6.9% Fineness Modulus = 2.27 Sample Meets Specs ? N/A D(30) = 0.262 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.386 mm Plasticity Index = n/a Moisture %, as sampled = 9.1% D(60) = 0.578 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 1.785 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 9/73 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 100% 100.0% 0.0% 1.50" 37.50 100% 100.0% 0.0% 1.25" 31.50 100% 100.0% 0.0% 60% 60.0% 1.00" 25.00 100% 100.0% 0.0% 3/4" 19.00 100% 100% 100.0% 0.0% 5/8" 16.00 99% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 98% 98% 100.0% 0.0% 3/8" 9.50 98% 98% 100.0% 0.0% 40% 40.0% 1/4" 6.30 97% 100.0% 0.0% #4 4.75 97% 97% 100.0% 0.0% #8 2.36 95% 100.0% 0.0% 30% 30.0% #10 2.00 95% 95% 100.0% 0.0% #16 1.18 75% 100.0% 0.0% #20 0.850 67% 100.0% 0.0% 20% 20.0% #30 0.600 61% 100.0% 0.0% #40 0.425 56% 56% 100.0% 0.0% 10% 10.0% #50 0.300 36% 100.0% 0.0% #60 0.250 28% 100.0% 0.0% #80 0.180 17% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 12% 12% 100.0% 0.0% #140 0.106 9% 100.0% 0.0% Particle Size (mm) #170 0.090 8% 100.0% 0.0% #200 0.075 6.9% 6.9% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-2 @ 2.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 4a Arlington, WA 24 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Materials Testing & Consulting, Inc. Lab Sample: TP-2 @ 2.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 4b Arlington, WA 25 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SP, Poorly graded Sand Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-2 @ 5.5' Tested By: A. Eifrig brown Sample#: B19-1013 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.128 mm % Gravel = 5.4% Coeff. of Curvature, CC = 0.68 Specifications D(10) = 0.172 mm % Sand = 92.9% Coeff. of Uniformity, CU = 4.19 No Specs D(15) = 0.201 mm % Silt & Clay = 1.7% Fineness Modulus = 2.53 Sample Meets Specs ? N/A D(30) = 0.290 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.409 mm Plasticity Index = n/a Moisture %, as sampled = 25.9% D(60) = 0.719 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 1.930 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 2/63 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 99% 100.0% 0.0% 1.50" 37.50 99% 100.0% 0.0% 1.25" 31.50 98% 100.0% 0.0% 60% 60.0% 1.00" 25.00 97% 97% 100.0% 0.0% 3/4" 19.00 97% 97% 100.0% 0.0% 5/8" 16.00 97% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 97% 97% 100.0% 0.0% 3/8" 9.50 96% 96% 100.0% 0.0% 40% 40.0% 1/4" 6.30 95% 100.0% 0.0% #4 4.75 95% 95% 100.0% 0.0% #8 2.36 92% 100.0% 0.0% 30% 30.0% #10 2.00 92% 92% 100.0% 0.0% #16 1.18 71% 100.0% 0.0% #20 0.850 63% 100.0% 0.0% 20% 20.0% #30 0.600 57% 100.0% 0.0% #40 0.425 53% 53% 100.0% 0.0% 10% 10.0% #50 0.300 32% 100.0% 0.0% #60 0.250 23% 100.0% 0.0% #80 0.180 11% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 6% 6% 100.0% 0.0% #140 0.106 4% 100.0% 0.0% Particle Size (mm) #170 0.090 3% 100.0% 0.0% #200 0.075 1.7% 1.7% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-2 @ 5.5â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 5 Arlington, WA 26 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SP-SM, Poorly graded Sand with Silt Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-4 @ 3.0' Tested By: A. Eifrig brown Sample#: B19-1014 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.051 mm % Gravel = 0.0% Coeff. of Curvature, CC = 1.30 Specifications D(10) = 0.092 mm % Sand = 92.7% Coeff. of Uniformity, CU = 3.25 No Specs D(15) = 0.123 mm % Silt & Clay = 7.3% Fineness Modulus = 1.28 Sample Meets Specs ? N/A D(30) = 0.189 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.262 mm Plasticity Index = n/a Moisture %, as sampled = 8.0% D(60) = 0.299 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 0.408 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 1/13 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 100% 100.0% 0.0% 1.50" 37.50 100% 100.0% 0.0% 1.25" 31.50 100% 100.0% 0.0% 60% 60.0% 1.00" 25.00 100% 100.0% 0.0% 3/4" 19.00 100% 100.0% 0.0% 5/8" 16.00 100% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 100% 100% 100.0% 0.0% 3/8" 9.50 100% 100% 100.0% 0.0% 40% 40.0% 1/4" 6.30 100% 100.0% 0.0% #4 4.75 100% 100% 100.0% 0.0% #8 2.36 100% 100.0% 0.0% 30% 30.0% #10 2.00 100% 100% 100.0% 0.0% #16 1.18 97% 100.0% 0.0% #20 0.850 96% 100.0% 0.0% 20% 20.0% #30 0.600 95% 100.0% 0.0% #40 0.425 95% 95% 100.0% 0.0% 10% 10.0% #50 0.300 60% 100.0% 0.0% #60 0.250 47% 100.0% 0.0% #80 0.180 28% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 19% 19% 100.0% 0.0% #140 0.106 12% 100.0% 0.0% Particle Size (mm) #170 0.090 10% 100.0% 0.0% #200 0.075 7.3% 7.3% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-4 @ 3.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 6a Arlington, WA 27 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Materials Testing & Consulting, Inc. Lab Sample: TP-4 @ 3.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 6b Arlington, WA 28 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SP, Poorly graded Sand Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-5 @ 4.0' Tested By: A. Eifrig brown Sample#: B19-1015 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.108 mm % Gravel = 0.2% Coeff. of Curvature, CC = 1.01 Specifications D(10) = 0.152 mm % Sand = 98.3% Coeff. of Uniformity, CU = 2.35 No Specs D(15) = 0.173 mm % Silt & Clay = 1.5% Fineness Modulus = 1.80 Sample Meets Specs ? N/A D(30) = 0.234 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.317 mm Plasticity Index = n/a Moisture %, as sampled = 30.7% D(60) = 0.358 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 1.372 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 1/50 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 100% 100.0% 0.0% 1.50" 37.50 100% 100.0% 0.0% 1.25" 31.50 100% 100.0% 0.0% 60% 60.0% 1.00" 25.00 100% 100.0% 0.0% 3/4" 19.00 100% 100.0% 0.0% 5/8" 16.00 100% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 100% 100% 100.0% 0.0% 3/8" 9.50 100% 100% 100.0% 0.0% 40% 40.0% 1/4" 6.30 100% 100.0% 0.0% #4 4.75 100% 100% 100.0% 0.0% #8 2.36 99% 100.0% 0.0% 30% 30.0% #10 2.00 99% 99% 100.0% 0.0% #16 1.18 87% 100.0% 0.0% #20 0.850 82% 100.0% 0.0% 20% 20.0% #30 0.600 79% 100.0% 0.0% #40 0.425 76% 76% 100.0% 0.0% 10% 10.0% #50 0.300 46% 100.0% 0.0% #60 0.250 34% 100.0% 0.0% #80 0.180 17% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 9% 9% 100.0% 0.0% #140 0.106 5% 100.0% 0.0% Particle Size (mm) #170 0.090 3% 100.0% 0.0% #200 0.075 1.5% 1.5% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-5 @ 4.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 7 Arlington, WA 29 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SM, Silty Sand Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-6 @ 2.0' Tested By: A. Eifrig brown Sample#: B19-1016 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.013 mm % Gravel = 0.4% Coeff. of Curvature, CC = 1.14 Specifications D(10) = 0.026 mm % Sand = 70.7% Coeff. of Uniformity, CU = 8.09 No Specs D(15) = 0.039 mm % Silt & Clay = 28.8% Fineness Modulus = 0.86 Sample Meets Specs ? N/A D(30) = 0.079 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.148 mm Plasticity Index = n/a Moisture %, as sampled = 25.9% D(60) = 0.211 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 0.404 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 30/97 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 100% 100.0% 0.0% 1.50" 37.50 100% 100.0% 0.0% 1.25" 31.50 100% 100.0% 0.0% 60% 60.0% 1.00" 25.00 100% 100.0% 0.0% 3/4" 19.00 100% 100.0% 0.0% 5/8" 16.00 100% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 100% 100% 100.0% 0.0% 3/8" 9.50 100% 100% 100.0% 0.0% 40% 40.0% 1/4" 6.30 100% 100.0% 0.0% #4 4.75 100% 100% 100.0% 0.0% #8 2.36 99% 100.0% 0.0% 30% 30.0% #10 2.00 99% 99% 100.0% 0.0% #16 1.18 96% 100.0% 0.0% #20 0.850 95% 100.0% 0.0% 20% 20.0% #30 0.600 94% 100.0% 0.0% #40 0.425 93% 93% 100.0% 0.0% 10% 10.0% #50 0.300 74% 100.0% 0.0% #60 0.250 66% 100.0% 0.0% #80 0.180 55% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 51% 51% 100.0% 0.0% #140 0.106 38% 100.0% 0.0% Particle Size (mm) #170 0.090 33% 100.0% 0.0% #200 0.075 28.8% 28.8% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-6 @ 2.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 8a Arlington, WA 30 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Materials Testing & Consulting, Inc. Lab Sample: TP-6 @ 2.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 8b Arlington, WA 31 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Materials Testing & Consulting, Inc. Geotechnical Engineering â€¢ Special Inspection â€¢ Materials Testing â€¢ Environmental Consulting Project: Trailer Boss Infiltration & Mounding Study Client: Terra Vista NW, LLC Project #: 19B335 Date Received: October 22, 2019 Sampled by: M. Furman Date Tested: October 23, 2019 Tested by: A. Eifrig Amount of Materials Finer Than #200 Sieve - ASTM C-117, ASTM D-1140 & AASHTO T-11 Sample # Location Tare Before Wash + Tare After Wash + Tare Amount of Loss % -#200 B19-1017 TP-6 @ 5.2' 731.4 1743.9 1489.5 254.4 25.1% 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! All results apply only to actual locatio ns and materials tested. As a mutual protectio n to clients, the public and ourselves, all reports are submitted as the confidential p rop erty of clients, and authorization for publication of statements, conclusions or extracts from or regarding our rep orts is reserved pending our written approval. Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-6 @ 5.2â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 9 Arlington, WA 32 TerraVista NW,LLC Appendix C Operation and Maintenance TerraVista NW,LLC Operation and Maintenance Procedures The following maintenance standards are as described in Volume V, Section 4.6.6, Table 5.3 of the SWMMWW. Table V-4.5.2(2) Maintenance Standards - Infiltration Maintenance Defect Conditions When Maintenance Results Expected When Component Is Needed Maintenance Is Performed General Trash & Debris See "Detention Ponds" (No. 1). See "Detention Ponds" (No. 1). Poisonous/Noxious See "Detention Ponds" (No. 1). See "Detention Ponds" Vegetation (No. 1). Contaminants and See "Detention Ponds" (No. 1). See "Detention Ponds" Pollution (No. 1). Rodent Holes See "Detention Ponds" (No. 1). See "Detention Ponds" (No. 1). Storage Area Sediment Water ponding in infiltration pond Sediment is removed after rainfall ceases and appropriate and/or facility is cleaned time allowed for infiltration. so that infiltration system Treatment basins should infiltrate works according to design. Water Quality Design Storm Volume within 48 hours, and empty within 24 hours after cessation of most rain events TerraVista NW,LLC Operation and Maintenance Procedures (A percolation test pit or test of facility indicates facility is only working at 90% of its designed capabilities. Test every 2 to 5 years. If two inches or more sediment is present, remove). Filter Bags (if Filled with Sediment and debris fill bag more Filter bag is replaced or applicable) Sediment and than 1/2 full. system is redesigned. Debris Rock Filters Sediment and By visual inspection, little or no Gravel in rock filter is Debris water flows through filter during replaced. heavy rain storms. Side Slopes of Erosion See "Detention Ponds" (No. 1). See "Detention Ponds" Pond (No. 1). Emergency Tree Growth See "Detention Ponds" (No. 1). See "Detention Ponds" Overflow Spillway (No. 1). and Berms over 4 Piping See "Detention Ponds" (No. 1). See "Detention Ponds" feet in height. (No. 1). Emergency Rock Missing See "Detention Ponds" (No. 1). See "Detention Ponds" Overflow Spillway (No. 1). Erosion See "Detention Ponds" (No. 1). See "Detention Ponds" (No. 1). Pre-settling Ponds Facility or sump 6" or designed sediment trap depth Sediment is removed. and Vaults filled with Sediment of sediment. and/or debris TerraVista NW,LLC Operation and Maintenance Procedures Table V-4.5.2(5) Maintenance Standards - Catch Basins Maintenance Defect Conditions When Maintenance Is Needed Results Expected Component When Maintenance Is Performed General Trash and Debris Trash or debris which is located immediately No Trash or debris in front of the catch basin opening or is located immediately in blocking inlettingcapacity of the basin by front of catch basin or more than 10%. on grate opening. Trash or debris (in the basin) that exceeds 60 No trash or debris in percent of the sump depth as measured from the the bottom of basin to invert of the lowest catch basin. pipe into or out of the basin, but in no case less than a minimum of six inches clearance from the debris surface to the invert of the lowest pipe. Trash or debris in any inlet or outlet pipe Inlet and outlet pipes blocking more than 1/3 of its height. free of trash or debris. Dead animals or vegetation that could No dead animals or generate odors that could cause complaints vegetation present or dangerous gases (e.g., methane). within the catch basin. TerraVista NW,LLC Operation and Maintenance Procedures Sediment Sediment (in the basin) that exceeds 60 No sediment in the percent of the sump depth as measured from catch basin the bottom of basin to invert of the lowest pipe into or out of the basin, but in no case less than a minimum of 6 inches clearance from the sediment surface to the invert of the lowest pipe. Structure Damage Top slab has holes larger than 2 square Top slab is free of to Frame and/or inches or cracks wider than 1/4 inch holes Top Slab (Intent is to make sure no material is running and cracks into basin). Frame not sitting flush on top slab, i.e., Frame is sitting flush separation of more than 3/4 inch of the frame on the riser rings or top from the top slab. Frame not securely slab and firmly attached attached. Fractures or Cracks Maintenance person judges that structure is Basin replaced or in Basin unsound. repaired to design Walls/Bottom standards. Grout fillet has separated or cracked wider Pipe is regrouted and than 1/2 inch and longer than 1 foot at the secure at basin wall. joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. Settlement/ If failure of basin has created a safety, Basin replaced or Misalignment function, or design problem. repaired to design standards. TerraVista NW,LLC Operation and Maintenance Procedures Vegetation Vegetation growing across and blocking No vegetation blocking more opening to basin. than 10% of the basin opening. Vegetation growing in inlet/outlet pipe joints No vegetation or root that is more than six inches tall and less than growth present six inches apart. Contamination and See "Detention Ponds" (No. 1). No pollution present. Pollution Catch Basin Cover Not in Place Cover is missing or only partially in place. Catch basin cover is Cover Any open catch basin requires maintenance. closed Locking Mechanism cannot be opened by one Mechanism opens with Mechanism Not maintenance person with proper tools. Bolts proper tools. Working into frame have less than 1/2 inch of thread. Cover Difficult to One maintenance person cannot remove lid Cover can be removed Remove after applying normal lifting pressure. by one maintenance (Intent is keep cover from sealing off access person. to maintenance.) Ladder Latter Rungs Ladder is unsafe due to missing rungs, not Ladder meets design Unsafe securely attached to basin wall, standards and allows misalignment, rust, cracks, or sharp edges. maintenance person safe access. Metal Grates Grate Opening Grate with opening wider than 7/8 inch. Grate opening meets (If Applicable) Unsafe design standards. Trash and Debris Trash and debris that is blocking more than Grate free of trash and 20% of grate surface inletting capacity. debris. Damaged or Grate missing or brokenmember(s) of the Grate is in place and Missing grate. meets design standards. TerraVista NW,LLC Operation and Maintenance Procedures Table V-4.5.2(18) Maintenance Standards - Catchbasin Inserts Maintenance Defect Conditions When Maintenance Is Results Expected When Component Needed Maintenance is Performed General Sediment When sediment forms a cap over No sediment cap on the insert Accumulation the media and its unit. insert media of the insert and/or unit. Trash and Debris Trash and debris accumulates on Trash and debris removed Accumulation insert unitcreating a from insert unit. Runoff freely blockage/restriction. flows into catch basin. Media Insert Not Effluent water from media insert Effluent water from media Removing Oil has a visible sheen. insert is free of oils andhas no visible sheen. Media Insert Water Catch basin insert is saturated with Remove and replace media Saturated water and no longer has the insert. capacity to absorb. Media Insert-Oil Media oil saturated due to Remove and replace media Saturated petroleum spill that drains into insert. catch basin. Media Insert Use Media has been used beyond the Remove and replace media at Beyond Normal typical average life of media insert regular intervals, depending on Product Life product. insert product. TerraVista NW,LLC Appendix D Infiltration Trench Drainage Calculations WWHM2012 PROJECT REPORT General Model Information Project Name: TB Trench Site Name: Site Address: City: Report Date: 12/17/2019 Gage: Everett Data Start: 1948/10/01 Data End: 2009/09/30 Timestep: 15 Minute Precip Scale: 1.200 Version Date: 2019/09/13 Version: 4.2.17 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year TB Trench 12/17/2019 11:13:14 AM Page 2 Landuse Basin Data Predeveloped Land Use Site Basin Bypass: No GroundWater: No Pervious Land Use acre A B, Forest, Flat 1 Pervious Total 1 Impervious Land Use acre Impervious Total 0 Basin Total 1 Element Flows To: Surface Interflow Groundwater TB Trench 12/17/2019 11:13:14 AM Page 3 Mitigated Land Use Site Infiltration Bypass: No GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 1 Impervious Total 1 Basin Total 1 Element Flows To: Surface Interflow Groundwater Site Gravel Trench Site Gravel Trench TB Trench 12/17/2019 11:13:14 AM Page 4 Routing Elements Predeveloped Routing TB Trench 12/17/2019 11:13:14 AM Page 5 Mitigated Routing Site Gravel Trench Bottom Length: 455.00 ft. Bottom Width: 5.00 ft. Trench bottom slope 1: 0 To 1 Trench Left side slope 0: 0 To 1 Trench right side slope 2: 0 To 1 Material thickness of first layer: 2 Pour Space of material for first layer: 0.33 Material thickness of second layer: 0 Pour Space of material for second layer: 0 Material thickness of third layer: 0 Pour Space of material for third layer: 0 Infiltration On Infiltration rate: 10 Infiltration safety factor: 1 Wetted surface area On Total Volume Infiltrated (ac-ft.): 192.871 Total Volume Through Riser (ac-ft.): 0.009 Total Volume Through Facility (ac-ft.): 192.88 Percent Infiltrated: 100 Total Precip Applied to Facility: 0 Total Evap From Facility: 0 Discharge Structure Riser Height: 2 ft. Riser Diameter: 18 in. Element Flows To: Outlet 1 Outlet 2 Gravel Trench Bed Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.052 0.000 0.000 0.000 0.0222 0.052 0.000 0.000 0.526 0.0444 0.052 0.000 0.000 0.526 0.0667 0.052 0.001 0.000 0.526 0.0889 0.052 0.001 0.000 0.526 0.1111 0.052 0.001 0.000 0.526 0.1333 0.052 0.002 0.000 0.526 0.1556 0.052 0.002 0.000 0.526 0.1778 0.052 0.003 0.000 0.526 0.2000 0.052 0.003 0.000 0.526 0.2222 0.052 0.003 0.000 0.526 0.2444 0.052 0.004 0.000 0.526 0.2667 0.052 0.004 0.000 0.526 0.2889 0.052 0.005 0.000 0.526 0.3111 0.052 0.005 0.000 0.526 0.3333 0.052 0.005 0.000 0.526 0.3556 0.052 0.006 0.000 0.526 0.3778 0.052 0.006 0.000 0.526 0.4000 0.052 0.006 0.000 0.526 0.4222 0.052 0.007 0.000 0.526 0.4444 0.052 0.007 0.000 0.526 0.4667 0.052 0.008 0.000 0.526 0.4889 0.052 0.008 0.000 0.526 TB Trench 12/17/2019 11:13:14 AM Page 6 0.5111 0.052 0.008 0.000 0.526 0.5333 0.052 0.009 0.000 0.526 0.5556 0.052 0.009 0.000 0.526 0.5778 0.052 0.010 0.000 0.526 0.6000 0.052 0.010 0.000 0.526 0.6222 0.052 0.010 0.000 0.526 0.6444 0.052 0.011 0.000 0.526 0.6667 0.052 0.011 0.000 0.526 0.6889 0.052 0.011 0.000 0.526 0.7111 0.052 0.012 0.000 0.526 0.7333 0.052 0.012 0.000 0.526 0.7556 0.052 0.013 0.000 0.526 0.7778 0.052 0.013 0.000 0.526 0.8000 0.052 0.013 0.000 0.526 0.8222 0.052 0.014 0.000 0.526 0.8444 0.052 0.014 0.000 0.526 0.8667 0.052 0.014 0.000 0.526 0.8889 0.052 0.015 0.000 0.526 0.9111 0.052 0.015 0.000 0.526 0.9333 0.052 0.016 0.000 0.526 0.9556 0.052 0.016 0.000 0.526 0.9778 0.052 0.016 0.000 0.526 1.0000 0.052 0.017 0.000 0.526 1.0222 0.052 0.017 0.000 0.526 1.0444 0.052 0.018 0.000 0.526 1.0667 0.052 0.018 0.000 0.526 1.0889 0.052 0.018 0.000 0.526 1.1111 0.052 0.019 0.000 0.526 1.1333 0.052 0.019 0.000 0.526 1.1556 0.052 0.019 0.000 0.526 1.1778 0.052 0.020 0.000 0.526 1.2000 0.052 0.020 0.000 0.526 1.2222 0.052 0.021 0.000 0.526 1.2444 0.052 0.021 0.000 0.526 1.2667 0.052 0.021 0.000 0.526 1.2889 0.052 0.022 0.000 0.526 1.3111 0.052 0.022 0.000 0.526 1.3333 0.052 0.023 0.000 0.526 1.3556 0.052 0.023 0.000 0.526 1.3778 0.052 0.023 0.000 0.526 1.4000 0.052 0.024 0.000 0.526 1.4222 0.052 0.024 0.000 0.526 1.4444 0.052 0.024 0.000 0.526 1.4667 0.052 0.025 0.000 0.526 1.4889 0.052 0.025 0.000 0.526 1.5111 0.052 0.026 0.000 0.526 1.5333 0.052 0.026 0.000 0.526 1.5556 0.052 0.026 0.000 0.526 1.5778 0.052 0.027 0.000 0.526 1.6000 0.052 0.027 0.000 0.526 1.6222 0.052 0.028 0.000 0.526 1.6444 0.052 0.028 0.000 0.526 1.6667 0.052 0.028 0.000 0.526 1.6889 0.052 0.029 0.000 0.526 1.7111 0.052 0.029 0.000 0.526 1.7333 0.052 0.029 0.000 0.526 1.7556 0.052 0.030 0.000 0.526 1.7778 0.052 0.030 0.000 0.526 TB Trench 12/17/2019 11:13:14 AM Page 7 1.8000 0.052 0.031 0.000 0.526 1.8222 0.052 0.031 0.000 0.526 1.8444 0.052 0.031 0.000 0.526 1.8667 0.052 0.032 0.000 0.526 1.8889 0.052 0.032 0.000 0.526 1.9111 0.052 0.032 0.000 0.526 1.9333 0.052 0.033 0.000 0.526 1.9556 0.052 0.033 0.000 0.526 1.9778 0.052 0.034 0.000 0.526 2.0000 0.052 0.034 0.000 0.526 TB Trench 12/17/2019 11:13:14 AM Page 8 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area: 1 Total Impervious Area: 0 Mitigated Landuse Totals for POC #1 Total Pervious Area: 0 Total Impervious Area: 1 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.001148 5 year 0.002489 10 year 0.003993 25 year 0.006974 50 year 0.010306 100 year 0.014949 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0 5 year 0 10 year 0 25 year 0 50 year 0 100 year 0 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.001 0.000 1950 0.002 0.000 1951 0.002 0.000 1952 0.001 0.000 1953 0.001 0.000 1954 0.006 0.000 1955 0.004 0.000 1956 0.001 0.000 1957 0.001 0.000 1958 0.001 0.000 TB Trench 12/17/2019 11:13:14 AM Page 9 1959 0.002 0.000 1960 0.001 0.000 1961 0.004 0.217 1962 0.001 0.000 1963 0.001 0.000 1964 0.003 0.000 1965 0.001 0.000 1966 0.001 0.000 1967 0.002 0.000 1968 0.001 0.000 1969 0.001 0.000 1970 0.001 0.000 1971 0.004 0.000 1972 0.001 0.000 1973 0.001 0.000 1974 0.002 0.000 1975 0.001 0.000 1976 0.002 0.000 1977 0.001 0.000 1978 0.001 0.000 1979 0.002 0.000 1980 0.001 0.000 1981 0.001 0.000 1982 0.001 0.000 1983 0.001 0.000 1984 0.001 0.000 1985 0.001 0.000 1986 0.007 0.000 1987 0.005 0.000 1988 0.001 0.000 1989 0.001 0.000 1990 0.001 0.000 1991 0.001 0.000 1992 0.001 0.000 1993 0.001 0.000 1994 0.001 0.000 1995 0.001 0.000 1996 0.009 0.000 1997 0.025 0.000 1998 0.001 0.000 1999 0.001 0.000 2000 0.001 0.000 2001 0.001 0.000 2002 0.001 0.000 2003 0.001 0.000 2004 0.001 0.000 2005 0.001 0.000 2006 0.027 0.000 2007 0.001 0.000 2008 0.001 0.000 2009 0.001 0.000 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0266 0.2167 2 0.0248 0.0000 3 0.0090 0.0000 TB Trench 12/17/2019 11:13:43 AM Page 10 4 0.0070 0.0000 5 0.0055 0.0000 6 0.0046 0.0000 7 0.0042 0.0000 8 0.0039 0.0000 9 0.0038 0.0000 10 0.0026 0.0000 11 0.0023 0.0000 12 0.0021 0.0000 13 0.0018 0.0000 14 0.0018 0.0000 15 0.0017 0.0000 16 0.0016 0.0000 17 0.0016 0.0000 18 0.0015 0.0000 19 0.0015 0.0000 20 0.0013 0.0000 21 0.0012 0.0000 22 0.0012 0.0000 23 0.0009 0.0000 24 0.0008 0.0000 25 0.0008 0.0000 26 0.0008 0.0000 27 0.0008 0.0000 28 0.0008 0.0000 29 0.0008 0.0000 30 0.0008 0.0000 31 0.0008 0.0000 32 0.0008 0.0000 33 0.0008 0.0000 34 0.0008 0.0000 35 0.0008 0.0000 36 0.0008 0.0000 37 0.0008 0.0000 38 0.0008 0.0000 39 0.0008 0.0000 40 0.0008 0.0000 41 0.0008 0.0000 42 0.0008 0.0000 43 0.0008 0.0000 44 0.0008 0.0000 45 0.0008 0.0000 46 0.0008 0.0000 47 0.0008 0.0000 48 0.0008 0.0000 49 0.0008 0.0000 50 0.0008 0.0000 51 0.0008 0.0000 52 0.0008 0.0000 53 0.0008 0.0000 54 0.0008 0.0000 55 0.0008 0.0000 56 0.0008 0.0000 57 0.0008 0.0000 58 0.0008 0.0000 59 0.0007 0.0000 60 0.0007 0.0000 61 0.0006 0.0000 TB Trench 12/17/2019 11:13:43 AM Page 11 TB Trench 12/17/2019 11:13:43 AM Page 12 Duration Flows The Facility PASSED Flow(cfs) Predev Mit Percentage Pass/Fail 0.0006 2353 3 0 Pass 0.0007 1324 3 0 Pass 0.0008 437 3 0 Pass 0.0009 112 3 2 Pass 0.0010 102 3 2 Pass 0.0011 89 3 3 Pass 0.0012 77 3 3 Pass 0.0013 66 3 4 Pass 0.0014 61 3 4 Pass 0.0015 58 3 5 Pass 0.0016 54 3 5 Pass 0.0017 50 3 6 Pass 0.0018 49 3 6 Pass 0.0019 47 3 6 Pass 0.0020 43 3 6 Pass 0.0020 40 3 7 Pass 0.0021 36 3 8 Pass 0.0022 36 3 8 Pass 0.0023 32 3 9 Pass 0.0024 31 3 9 Pass 0.0025 31 3 9 Pass 0.0026 29 3 10 Pass 0.0027 29 3 10 Pass 0.0028 27 3 11 Pass 0.0029 26 3 11 Pass 0.0030 26 3 11 Pass 0.0031 26 3 11 Pass 0.0032 25 3 12 Pass 0.0033 23 3 13 Pass 0.0034 23 3 13 Pass 0.0035 23 3 13 Pass 0.0036 23 3 13 Pass 0.0037 23 3 13 Pass 0.0038 21 3 14 Pass 0.0039 19 3 15 Pass 0.0040 18 3 16 Pass 0.0041 17 3 17 Pass 0.0042 16 3 18 Pass 0.0043 16 3 18 Pass 0.0044 15 3 20 Pass 0.0045 15 3 20 Pass 0.0046 14 3 21 Pass 0.0047 13 3 23 Pass 0.0048 13 3 23 Pass 0.0049 13 3 23 Pass 0.0050 13 3 23 Pass 0.0051 13 3 23 Pass 0.0052 13 3 23 Pass 0.0053 13 3 23 Pass 0.0054 13 3 23 Pass 0.0055 13 3 23 Pass 0.0056 11 3 27 Pass 0.0057 11 3 27 Pass TB Trench 12/17/2019 11:13:43 AM Page 13 0.0058 11 3 27 Pass 0.0059 11 3 27 Pass 0.0060 11 3 27 Pass 0.0061 11 3 27 Pass 0.0062 11 3 27 Pass 0.0063 11 3 27 Pass 0.0064 11 3 27 Pass 0.0065 11 3 27 Pass 0.0066 11 3 27 Pass 0.0067 11 3 27 Pass 0.0068 11 3 27 Pass 0.0069 10 3 30 Pass 0.0070 10 3 30 Pass 0.0071 9 3 33 Pass 0.0072 9 3 33 Pass 0.0073 8 3 37 Pass 0.0074 8 3 37 Pass 0.0075 8 3 37 Pass 0.0076 8 3 37 Pass 0.0077 8 3 37 Pass 0.0078 8 3 37 Pass 0.0078 8 3 37 Pass 0.0079 8 3 37 Pass 0.0080 8 3 37 Pass 0.0081 8 3 37 Pass 0.0082 8 3 37 Pass 0.0083 8 3 37 Pass 0.0084 8 3 37 Pass 0.0085 8 3 37 Pass 0.0086 8 3 37 Pass 0.0087 7 3 42 Pass 0.0088 7 3 42 Pass 0.0089 7 3 42 Pass 0.0090 7 3 42 Pass 0.0091 6 3 50 Pass 0.0092 6 3 50 Pass 0.0093 6 3 50 Pass 0.0094 6 3 50 Pass 0.0095 6 3 50 Pass 0.0096 6 3 50 Pass 0.0097 6 3 50 Pass 0.0098 6 3 50 Pass 0.0099 6 3 50 Pass 0.0100 6 3 50 Pass 0.0101 6 3 50 Pass 0.0102 5 3 60 Pass 0.0103 5 3 60 Pass TB Trench 12/17/2019 11:13:43 AM Page 14 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0 acre-feet On-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. Off-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. TB Trench 12/17/2019 11:13:43 AM Page 15 LID Report TB Trench 12/17/2019 11:13:43 AM Page 16 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. TB Trench 12/17/2019 11:13:50 AM Page 17 Appendix Predeveloped Schematic TB Trench 12/17/2019 11:13:50 AM Page 18 Mitigated Schematic TB Trench 12/17/2019 11:13:52 AM Page 19 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 TB Trench.wdm MESSU 25 PreTB Trench.MES 27 PreTB Trench.L61 28 PreTB Trench.L62 30 POCTB Trench1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Site Basin MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 A/B, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 1 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 1 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO TB Trench 12/17/2019 11:13:53 AM Page 20 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 1 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 1 0 5 2 400 0.05 0.3 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 1 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 1 0.2 0.5 0.35 0 0.7 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 1 0 0 0 0 3 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 TB Trench 12/17/2019 11:13:53 AM Page 21 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Site Basin*** PERLND 1 1 COPY 501 12 PERLND 1 1 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1.2 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1.2 IMPLND 1 999 EXTNL PREC TB Trench 12/17/2019 11:13:53 AM Page 22 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN TB Trench 12/17/2019 11:13:53 AM Page 23 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 TB Trench.wdm MESSU 25 MitTB Trench.MES 27 MitTB Trench.L61 28 MitTB Trench.L62 30 POCTB Trench1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 IMPLND 1 RCHRES 1 COPY 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Site Gravel Trench MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* END PRINT-INFO PWAT-PARM1 TB Trench 12/17/2019 11:13:53 AM Page 24 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATE1 TB Trench 12/17/2019 11:13:53 AM Page 25 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Site Infiltration*** IMPLND 1 1 RCHRES 1 5 ******Routing****** IMPLND 1 1 COPY 1 15 RCHRES 1 1 COPY 501 17 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Site Gravel Tren-013 2 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 5 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.09 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS TB Trench 12/17/2019 11:13:53 AM Page 26 FTABLES FTABLE 1 92 5 Depth Area Volume Outflow1 Outflow2 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (cfs) (ft/sec) (Minutes)*** 0.000000 0.052227 0.000000 0.000000 0.000000 0.022222 0.052227 0.000383 0.000000 0.526620 0.044444 0.052227 0.000766 0.000000 0.526620 0.066667 0.052227 0.001149 0.000000 0.526620 0.088889 0.052227 0.001532 0.000000 0.526620 0.111111 0.052227 0.001915 0.000000 0.526620 0.133333 0.052227 0.002298 0.000000 0.526620 0.155556 0.052227 0.002681 0.000000 0.526620 0.177778 0.052227 0.003064 0.000000 0.526620 0.200000 0.052227 0.003447 0.000000 0.526620 0.222222 0.052227 0.003830 0.000000 0.526620 0.244444 0.052227 0.004213 0.000000 0.526620 0.266667 0.052227 0.004596 0.000000 0.526620 0.288889 0.052227 0.004979 0.000000 0.526620 0.311111 0.052227 0.005362 0.000000 0.526620 0.333333 0.052227 0.005745 0.000000 0.526620 0.355556 0.052227 0.006128 0.000000 0.526620 0.377778 0.052227 0.006511 0.000000 0.526620 0.400000 0.052227 0.006894 0.000000 0.526620 0.422222 0.052227 0.007277 0.000000 0.526620 0.444444 0.052227 0.007660 0.000000 0.526620 0.466667 0.052227 0.008043 0.000000 0.526620 0.488889 0.052227 0.008426 0.000000 0.526620 0.511111 0.052227 0.008809 0.000000 0.526620 0.533333 0.052227 0.009192 0.000000 0.526620 0.555556 0.052227 0.009575 0.000000 0.526620 0.577778 0.052227 0.009958 0.000000 0.526620 0.600000 0.052227 0.010341 0.000000 0.526620 0.622222 0.052227 0.010724 0.000000 0.526620 0.644444 0.052227 0.011107 0.000000 0.526620 0.666667 0.052227 0.011490 0.000000 0.526620 0.688889 0.052227 0.011873 0.000000 0.526620 0.711111 0.052227 0.012256 0.000000 0.526620 0.733333 0.052227 0.012639 0.000000 0.526620 0.755556 0.052227 0.013022 0.000000 0.526620 0.777778 0.052227 0.013405 0.000000 0.526620 0.800000 0.052227 0.013788 0.000000 0.526620 0.822222 0.052227 0.014171 0.000000 0.526620 0.844444 0.052227 0.014554 0.000000 0.526620 0.866667 0.052227 0.014937 0.000000 0.526620 0.888889 0.052227 0.015320 0.000000 0.526620 0.911111 0.052227 0.015703 0.000000 0.526620 0.933333 0.052227 0.016086 0.000000 0.526620 0.955556 0.052227 0.016469 0.000000 0.526620 0.977778 0.052227 0.016852 0.000000 0.526620 1.000000 0.052227 0.017235 0.000000 0.526620 1.022222 0.052227 0.017618 0.000000 0.526620 1.044444 0.052227 0.018001 0.000000 0.526620 1.066667 0.052227 0.018384 0.000000 0.526620 1.088889 0.052227 0.018767 0.000000 0.526620 1.111111 0.052227 0.019150 0.000000 0.526620 1.133333 0.052227 0.019533 0.000000 0.526620 1.155556 0.052227 0.019916 0.000000 0.526620 1.177778 0.052227 0.020299 0.000000 0.526620 1.200000 0.052227 0.020682 0.000000 0.526620 1.222222 0.052227 0.021065 0.000000 0.526620 1.244444 0.052227 0.021448 0.000000 0.526620 1.266667 0.052227 0.021831 0.000000 0.526620 1.288889 0.052227 0.022214 0.000000 0.526620 1.311111 0.052227 0.022597 0.000000 0.526620 1.333333 0.052227 0.022980 0.000000 0.526620 1.355556 0.052227 0.023363 0.000000 0.526620 1.377778 0.052227 0.023746 0.000000 0.526620 1.400000 0.052227 0.024129 0.000000 0.526620 1.422222 0.052227 0.024512 0.000000 0.526620 TB Trench 12/17/2019 11:13:53 AM Page 27 1.444444 0.052227 0.024895 0.000000 0.526620 1.466667 0.052227 0.025278 0.000000 0.526620 1.488889 0.052227 0.025661 0.000000 0.526620 1.511111 0.052227 0.026044 0.000000 0.526620 1.533333 0.052227 0.026427 0.000000 0.526620 1.555556 0.052227 0.026810 0.000000 0.526620 1.577778 0.052227 0.027193 0.000000 0.526620 1.600000 0.052227 0.027576 0.000000 0.526620 1.622222 0.052227 0.027959 0.000000 0.526620 1.644444 0.052227 0.028342 0.000000 0.526620 1.666667 0.052227 0.028725 0.000000 0.526620 1.688889 0.052227 0.029108 0.000000 0.526620 1.711111 0.052227 0.029491 0.000000 0.526620 1.733333 0.052227 0.029874 0.000000 0.526620 1.755556 0.052227 0.030257 0.000000 0.526620 1.777778 0.052227 0.030640 0.000000 0.526620 1.800000 0.052227 0.031023 0.000000 0.526620 1.822222 0.052227 0.031406 0.000000 0.526620 1.844444 0.052227 0.031789 0.000000 0.526620 1.866667 0.052227 0.032172 0.000000 0.526620 1.888889 0.052227 0.032555 0.000000 0.526620 1.911111 0.052227 0.032938 0.000000 0.526620 1.933333 0.052227 0.033321 0.000000 0.526620 1.955556 0.052227 0.033704 0.000000 0.526620 1.977778 0.052227 0.034087 0.000000 0.526620 2.000000 0.052227 0.034470 0.000000 0.526620 2.022222 0.052227 0.035630 0.052737 0.526620 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1.2 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1.2 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 1 HYDR RO 1 1 1 WDM 1014 FLOW ENGL REPL RCHRES 1 HYDR O 1 1 1 WDM 1015 FLOW ENGL REPL RCHRES 1 HYDR O 2 1 1 WDM 1016 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1017 STAG ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 17 RCHRES OFLOW OVOL 1 COPY INPUT MEAN END MASS-LINK 17 END MASS-LINK END RUN TB Trench 12/17/2019 11:13:53 AM Page 28 TB Trench 12/17/2019 11:13:53 AM Page 29 Predeveloped HSPF Message File TB Trench 12/17/2019 11:13:53 AM Page 30 Mitigated HSPF Message File ERROR/WARNING ID: 341 6 DATE/TIME: 1960/10/23 9:30 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 92 1501.5 1552.0 1730.8 ERROR/WARNING ID: 341 5 DATE/TIME: 1960/10/23 9:30 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 4550.0 -2.065E+04 4.5382 4.5382E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1960/10/23 9:45 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 92 1.5015E+03 1552.0 1687.4 ERROR/WARNING ID: 341 5 DATE/TIME: 1960/10/23 9:45 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 4550.0 -1.674E+04 3.6794 3.6794E+00 2 TB Trench 12/17/2019 11:13:53 AM Page 31 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright Â© by : Clear Creek Solutions, Inc. 2005-2019; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com TB Trench 12/17/2019 11:13:53 AM Page 32 SEPA ENVIRONMENTAL CHECKLIST Purpose of checklist: Governmental agencies use this checklist to help determine whether the environmental impacts of your proposal are significant. This information is also helpful to determine if available avoidance, minimization or compensatory mitigation measures will address the probable significant impacts or if an environmental impact statement will be prepared to further analyze the proposal. Instructions for applicants: This environmental checklist asks you to describe some basic information about your proposal. Please answer each question accurately and carefully, to the best of your knowledge. You may need to consult with an agency specialist or private consultant for some questions. You may use â€œnot applicableâ€ or "does not apply" only when you can explain why it does not apply and not when the answer is unknown. You may also attach or incorporate by reference additional studies reports. Complete and accurate answers to these questions often avoid delays with the SEPA process as well as later in the decision- making process. The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on different parcels of land. Attach any additional information that will help describe your proposal or its environmental effects. The agency to which you submit this checklist may ask you to explain your answers or provide additional information reasonably related to determining if there may be significant adverse impact. Instructions for Lead Agencies: Please adjust the format of this template as needed. Additional information may be necessary to evaluate the existing environment, all interrelated aspects of the proposal and an analysis of adverse impacts. The checklist is considered the first but not necessarily the only source of information needed to make an adequate threshold determination. Once a threshold determination is made, the lead agency is responsible for the completeness and accuracy of the checklist and other supporting documents. Use of checklist for nonproject proposals: For nonproject proposals (such as ordinances, regulations, plans and programs), complete the applicable parts of sections A and B plus the SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS (part D). Please completely answer all questions that apply and note that the words "project," "applicant," and "property or site" should be read as "proposal," "proponent," and "affected geographic area," respectively. The lead agency may exclude (for non-projects) questions in Part B - Environmental Elements â€“that do not contribute meaningfully to the analysis of the proposal. A. Background [HELP] 1. Name of proposed project, if applicable: Trailer Boss 2. Name of applicant: TerraVista NW Consulting Engineers SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 1 of 13 3. Address and phone number of applicant and contact person: 3204 Smokey Point Drive, Suite 207 Arlington, WA 98223 4. Date checklist prepared: Juny 31, 2019 5. Agency requesting checklist: City of Arlington 6. Proposed timing or schedule (including phasing, if applicable): Construction is estimated to begin in Aug 2019 and be complete in March 2020. 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. No 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. Geotechnical report 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. Yes, zoning permit and SEPA approval through the City of Arlington. Construction General Permit though Dept of Ecology 10. List any government approvals or permits that will be needed for your proposal, if known. SEPA and Zoning Permit 11. Give brief, complete description of your proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. (Lead agencies may modify this form to include additional specific information on project description.) The project is located on Smokey Point Blvd on a 2.28 acre site. The proposed use for the site will be utility trailer sales. 12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed project, including a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applications related to this checklist. The project is located at the corner of Smokey Point Blvd and 166th Pl in Arlington. B. Environmental Elements [HELP] 1. Earth [help] a. General description of the site: (circle one): Flat, rolling, hilly, steep slopes, mountainous, other _____________ SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 2 of 13 b. What is the steepest slope on the site (approximate percent slope)? 0% c. What general types of soils are found on the site (for example, clay, sand, gravel, peat, muck)? If you know the classification of agricultural soils, specify them and note any agricultural land of long-term commercial significance and whether the proposal results in removing any of these soils. The test pits conducted for this study encountered native silty sands and sands beneath a thin layer of fill soil or topsoil. Underlying the fill and/or topsoil, we observed weathered silty sand soils that were loose. The fill and weathered soil was approximately 1 to 2.5 feet deep, and beneath these soils tan, medium dense, native, slightly silty sand was encountered. Beneath the tan sands, we encountered dense, gray sand that extended to the bottom of all of our pits (6 foot max explored depth at the site). This sand soil is typical for the native conditions encountered in the general vicinity. d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. No e. Describe the purpose, type, total area, and approximate quantities and total affected area of any filling, excavation, and grading proposed. Indicate source of fill. Site will be cleared and graded to facilitiate development of the building and parking area. Approximately 4,000 cy fill will be needed to raise the site to finish grade. f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe. No, site is flat with high infiltration rates. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? 90% h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: A stormwater pollution prevention plan (SWPPP) will be prepared that identifies best management practices (BMPâ€™s) that will be employed to manage erosion onsite. 2. Air [help] a. What types of emissions to the air would result from the proposal during construction, operation, and maintenance when the project is completed? If any, generally describe and give approximate quantities if known. Emissions from standard construction equipment. After project completion, emissions will be from staff vehicles and delivery trucks. b. Are there any off-site sources of emissions or odor that may affect your proposal? If so, generally describe. No c. Proposed measures to reduce or control emissions or other impacts to air, if any: Construction equipment emissions will comply with all State and Federal regulations for emissions. 3. Water [help] a. Surface Water: [help] SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 3 of 13 1) Is there any surface water body on or in the immediate vicinity of the site (including year-round and seasonal streams, saltwater, lakes, ponds, wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. No 2) Will the project require any work over, in, or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. No 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. NA 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known. No 5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan. No 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. No b. Ground Water: [help] 1) Will groundwater be withdrawn from a well for drinking water or other purposes? If so, give a general description of the well, proposed uses and approximate quantities withdrawn from the well. Will water be discharged to groundwater? Give general description, purpose, and approximate quantities if known. No 2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, containing the following chemicals. . . ; agricultural; etc.). Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve. No waste material will be discharged into groundwater c. Water runoff (including stormwater): 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. Stormwater runoff will be from two sources, roof runoff and parking lot runoff. Roof runoff will be routed to below grade infiltration facilities. Parking lot runoff will be routed to infiltration facilities with a water quality layer. 2) Could waste materials enter ground or surface waters? If so, generally describe. Waste materials are not anticipated to enter ground water sources. In the event of an accidential spill, a spill prevent plan and spill kit will be onsite. 3) Does the proposal alter or otherwise affect drainage patterns in the vicinity of the site? If so, describe. No, existing drainage patterns will be maintained. d. Proposed measures to reduce or control surface, ground, and runoff water, and drainage SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 4 of 13 pattern impacts, if any: Site will comply with the 2014 Stormwater Management Manual for Western Washington 4. Plants [help] a. Check the types of vegetation found on the site: ____deciduous tree: alder, maple, aspen, other ____evergreen tree: fir, cedar, pine, other ____shrubs __X_grass ____pasture ____crop or grain ____ Orchards, vineyards or other permanent crops. ____ wet soil plants: cattail, buttercup, bullrush, skunk cabbage, other ____water plants: water lily, eelgrass, milfoil, other ____other types of vegetation b. What kind and amount of vegetation will be removed or altered? Topsoil and grasses will be removed from the site. c. List threatened and endangered species known to be on or near the site. The site is flat, dry, and without trees or shrubs. Endangered species are not believed to be onsite. d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: New vegetation will include trees and shrubs. e. List all noxious weeds and invasive species known to be on or near the site. No invasive species are present on the site 5. Animals [help] a. List any birds and other animals which have been observed on or near the site or are known to be on or near the site. No birds or other animals have been observed at the site; however, it is anticpated that hawk, heron, eagle, songbirds, and deer may cross the site occasionally. Examples include: birds: hawk, heron, eagle, songbirds, other: mammals: deer, bear, elk, beaver, other: fish: bass, salmon, trout, herring, shellfish, other ________ b. List any threatened and endangered species known to be on or near the site. No known endangered species are present on the site. c. Is the site part of a migration route? If so, explain. No known migration routes onsite. d. Proposed measures to preserve or enhance wildlife, if any: Trees and shrubs will be added to the site, providing habitat for small birds. e. List any invasive animal species known to be on or near the site. SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 5 of 13 No known invasive species are onsite. 6. Energy and Natural Resources [help] a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. Electric b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. No c. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any: Electrical systems will comply with the current electrical code, which incudes energy conservations requirements. 7. Environmental Health [help] a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe. Hazardous chemical may be present onsite by future tenants. Chemicals stored onsite will be stored in accordance with State and Federal regulations. 1) Describe any known or possible contamination at the site from present or past uses. No known contamination 2) Describe existing hazardous chemicals/conditions that might affect project development and design. This includes underground hazardous liquid and gas transmission pipelines located within the project area and in the vicinity. None 3) Describe any toxic or hazardous chemicals that might be stored, used, or produced during the project's development or construction, or at any time during the operating life of the project. All stored chemicals will comply with all State and Federal safety and spill control requirements. 4) Describe special emergency services that might be required. Emergency services available to the site include fire and ems service. Emergency services will be aware of onsite chemicals and can respond accordingly. 5) Proposed measures to reduce or control environmental health hazards, if any: Hazardous chemicals will be stored in accordance with State and Federal regulations. b. Noise 1) What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? Sources of noise will be from construction equipment, which will comply with established noise ordinances. SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 6 of 13 2) What types and levels of noise would be created by or associated with the project on a short-term or a long-term basis (for example: traffic, construction, operation, other)? Indi- cate what hours noise would come from the site. Short term sources will be from construction equipment; long term sources will be from staff vehicles and tenant activities. 3) Proposed measures to reduce or control noise impacts, if any: Noise emmisions will comply with State and Federal regulations. 8. Land and Shoreline Use [help] a. What is the current use of the site and adjacent properties? Will the proposal affect current land uses on nearby or adjacent properties? If so, describe. Current use is undeveloped. A PUD substation is to the east, a SFR to the south, and a storage facility to the east. Public roadways are to the north and west. b. Has the project site been used as working farmlands or working forest lands? If so, describe. How much agricultural or forest land of long-term commercial significance will be converted to other uses as a result of the proposal, if any? If resource lands have not been designated, how many acres in farmland or forest land tax status will be converted to nonfarm or nonforest use? No 1) Will the proposal affect or be affected by surrounding working farm or forest land normal business operations, such as oversize equipment access, the application of pesticides, tilling, and harvesting? If so, how: No c. Describe any structures on the site. None d. Will any structures be demolished? If so, what? No e. What is the current zoning classification of the site? Highway Commercial -HI f. What is the current comprehensive plan designation of the site? Highway Commercial - HI g. If applicable, what is the current shoreline master program designation of the site? NA h. Has any part of the site been classified as a critical area by the city or county? If so, specify. No SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 7 of 13 i. Approximately how many people would reside or work in the completed project? 3 employees j. Approximately how many people would the completed project displace? None k. Proposed measures to avoid or reduce displacement impacts, if any: NA L. Proposed measures to ensure the proposal is compatible with existing and projected land uses and plans, if any: Project will be reviewed by the City of Arlington for compliance with current land use requirements. m. Proposed measures to reduce or control impacts to agricultural and forest lands of long-term commercial significance, if any: NA 9. Housing [help] a. Approximately how many units would be provided, if any? Indicate whether high, mid- dle, or low-income housing. NA, commercial development b. Approximately how many units, if any, would be eliminated? Indicate whether high, middle, or low-income housing. NA c. Proposed measures to reduce or control housing impacts, if any: NA 10. Aesthetics [help] a. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s) proposed? 24â€™ above grade b. What views in the immediate vicinity would be altered or obstructed? None. b. Proposed measures to reduce or control aesthetic impacts, if any: Architecture of facility will be in accordance with established architectural requirements of the City. 11. Light and Glare [help] a. What type of light or glare will the proposal produce? What time of day would it mainly occur? Site lighting will be provided on the building and within the site, with downward angled lights. b. Could light or glare from the finished project be a safety hazard or interfere with views? No c. What existing off-site sources of light or glare may affect your proposal? None SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 8 of 13 d. Proposed measures to reduce or control light and glare impacts, if any: None anticipated 12. Recreation [help] a. What designated and informal recreational opportunities are in the immediate vicinity? None b. Would the proposed project displace any existing recreational uses? If so, describe. No c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: None 13. Historic and cultural preservation [help] a. Are there any buildings, structures, or sites, located on or near the site that are over 45 years old listed in or eligible for listing in national, state, or local preservation registers ? If so, specifically describe. None b. Are there any landmarks, features, or other evidence of Indian or historic use or occupation? This may include human burials or old cemeteries. Are there any material evidence, artifacts, or areas of cultural importance on or near the site? Please list any professional studies conducted at the site to identify such resources. No evidence of historic use or occupation. c. Describe the methods used to assess the potential impacts to cultural and historic resources on or near the project site. Examples include consultation with tribes and the department of archeology and historic preservation, archaeological surveys, historic maps, GIS data, etc. Staff reviewed available GIS information from the City of Arlington; no information was available. d. Proposed measures to avoid, minimize, or compensate for loss, changes to, and disturbance to resources. Please include plans for the above and any permits that may be required. If inadvertent discovery of historically significant artifacts is made, the owner will contact local agencies including tribal agencies and department of archeology. 14. Transportation [help] a. Identify public streets and highways serving the site or affected geographic area and describe proposed access to the existing street system. Show on site plans, if any. Access to the site will be the adjacent roadways of Smokey Point Blvd and 166th Pl. SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 9 of 13 b. Is the site or affected geographic area currently served by public transit? If so, generally describe. If not, what is the approximate distance to the nearest transit stop? Transit travels along Smokey Point Blvd, there transit access is near the site. c. How many additional parking spaces would the completed project or non-project proposal have? How many would the project or proposal eliminate? The project will add approximately 10 passenger vehicle stalls. No stalls will be eliminated. d. Will the proposal require any new or improvements to existing roads, streets, pedestrian, bicycle or state transportation facilities, not including driveways? If so, generally describe (indicate whether public or private). The existing driveway access on Smokey Point Blvd will be widenend. e. Will the project or proposal use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No f. How many vehicular trips per day would be generated by the completed project or proposal? If known, indicate when peak volumes would occur and what percentage of the volume would be trucks (such as commercial and nonpassenger vehicles). What data or transportation models were used to make these estimates? 4 new PM peak-hour trips. g. Will the proposal interfere with, affect or be affected by the movement of agricultural and forest products on roads or streets in the area? If so, generally describe. No h. Proposed measures to reduce or control transportation impacts, if any: None 15. Public Services [help] a. Would the project result in an increased need for public services (for example: fire protection, police protection, public transit, health care, schools, other)? If so, generally describe. Current level emergency services are adequate to service the proprosed development. b. Proposed measures to reduce or control direct impacts on public services, if any. No measures taken, beyond those required by the IBC. SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 10 of 13 16. Utilities [help] a. Circle utilities currently available at the site: electricity, natural gas, water, refuse service, telephone, sanitary sewer, septic system, other ___________ c. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. Water, sewer, electricity, natural gas, telephone, cable C. Signature [HELP] The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: ___________________________________________________ Name of signee __Eric Scott________________________________________________ Position and Agency/Organization __TerraVista NW Consulting Engineers____________ Date Submitted: _____________ D. Supplemental sheet for nonproject actions [HELP] (IT IS NOT NECESSARY to use this sheet for project actions) Because these questions are very general, it may be helpful to read them in conjunction with the list of the elements of the environment. When answering these questions, be aware of the extent the proposal, or the types of activities likely to result from the proposal, would affect the item at a greater intensity or at a faster rate than if the proposal were not implemented. Respond briefly and in general terms. 1. How would the proposal be likely to increase discharge to water; emissions to air; pro- duction, storage, or release of toxic or hazardous substances; or production of noise? Proposed measures to avoid or reduce such increases are: 2. How would the proposal be likely to affect plants, animals, fish, or marine life? SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 11 of 13 Proposed measures to protect or conserve plants, animals, fish, or marine life are: 3. How would the proposal be likely to deplete energy or natural resources? Proposed measures to protect or conserve energy and natural resources are: 4. How would the proposal be likely to use or affect environmentally sensitive areas or areas designated (or eligible or under study) for governmental protection; such as parks, wilderness, wild and scenic rivers, threatened or endangered species habitat, historic or cultural sites, wetlands, floodplains, or prime farmlands? Proposed measures to protect such resources or to avoid or reduce impacts are: 5. How would the proposal be likely to affect land and shoreline use, including whether it would allow or encourage land or shoreline uses incompatible with existing plans? Proposed measures to avoid or reduce shoreline and land use impacts are: 6. How would the proposal be likely to increase demands on transportation or public services and utilities? Proposed measures to reduce or respond to such demand(s) are: SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 12 of 13 7. Identify, if possible, whether the proposal may conflict with local, state, or federal laws or requirements for the protection of the environment. SEPA Environmental checklist (WAC 197-11-960) July 2016 Page 13 of 13 NW 28 T31N R 5E LLC SITE Consulting Engineers TerraVista NW GENERAL INFORMATION TRAILER BOSS C1.1 Plotted: Aug 04, 2019 - 8:53pm Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C1.1-GEN INFO NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW 0 30 60 Scale in Feet PAVING PLAN TRAILER BOSS C2.2 Plotted: Aug 04, 2019 - 8:53pm Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C2.2 PAVING PLAN NW 28 T31N R 5E 0 20 40 Scale in Feet LLC Consulting Engineers TerraVista NW LANDSCAPE PLAN TRAILER BOSS L1.1 Plotted: Aug 04, 2019 - 8:53pm Eric T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: L1.1-LANDSCAPE April 8, 2016 JN16128 Axthelm Construction Inc. 17160 Dike Road Mount Vernon WA. 98273 Attention: Jim Axthelm Proposal: Geotechnical Engineering Study Proposed Autos Only Office and Garage 16523 Smokey Point Boulevard Marysville, WA Dear Mr. Axthelm: We are pleased to present this geotechnical report for the property at 16523 Smokey Point Boulevard in Marysville. We understand that two high bay, single-story (possibly with a mezzanine level) metal warehouses are proposed. As such, it appears that the relatively light and relatively uniform loading afforded by the metal- framed building will allow a conventional, continuous, foundation. We were provided with a preliminary site plan, developed by Axthelm Construction that appears as the background for our Site Exploration Plan on Plate 1. Based on this plan and our conversations with Jim Axthelm, we understand that two new metal framed buildings will be constructed on the site. The northwestern building will be an office and showroom; and the southeastern building will be a service building. The buildings will likely be steel-frame with mostly steel siding. We expect that the planned floor slabs will sit near the existing grades. If the scope of the project changes from what we have described above, we should be provided with revised plans in order to determine if modifications to the recommendations and conclusions of this report are warranted. SITE CONDITIONS SURFACE The site is located off of the eastern side of Smokey Pointe Boulevard just south of the Smokey Pointe area of Marysville. The irregular shaped property is on the southeastern corner of Smokey Pointe Boulevard and 166th Place Northeast. The site is bordered to the north by 166th Place Northeast and a daycare facility. Surrounding properties to the east, and south are residential or in development. The level subject site is currently developed with a portable trailer and gravel lot on the western end and undeveloped treed land on the east. North of the eastern portion of the site is a shallow existing detention pond. SUBSURFACE The subsurface conditions were explored by excavating four (4) test pits at the approximate locations shown on the Site Exploration Plan, Plate 1. Our exploration program was based on the proposed construction, anticipated subsurface conditions and those encountered during exploration, and the scope of work outlined in our proposal. The test pits were excavated on March 24, 2016 with a backhoe. A geotechnical engineer from our staff observed the excavation process, logged the test pits, and obtained representative samples of the soil GEOTECH CONSULTANTS, INC. Axthelm Construction. JN 16128 April 11, 2016 Page 2 encountered. "Grab" samples of selected subsurface soil were collected from the backhoe bucket. The Test Pit Logs are attached to this report as Plate 2. Soil Conditions The test pits conducted for this study encountered native silty sands and sands beneath a thin layer of fill soil or topsoil. Underlying the fill and/or topsoil, we observed weathered silty sand soils that were loose. The fill and weathered soil was approximately 1 to 2.5 feet deep, and beneath these soils tan, medium dense, native, slightly silty sand was encountered. Beneath the tan sands, we encountered dense, gray sand that extended to the bottom of all of our pits (6 foot max explored depth at the site). This sand soil is typical for the native conditions encountered in the general vicinity. Debris, buried utilities, and old foundation and slab elements are commonly encountered on sites that have had previous development. We also reviewed the boring logs for the Eagle Hardware site across Smokey Pointe Boulevard to the west. Six borings were drilled as part of the study in 1997, and Boring 6 was located just across Smokey Pointe Boulevard to the northwest of the subject site. The boring revealed similar soil conditions to those found in our test pits and confirmed that the gray sands are dense. We have attached a copy of this local boring log to this report. Groundwater Conditions Groundwater seepage was observed in all of the test pits from 3 to 5 feet below the existing ground surface. The test pits were left open for only a short time period. Therefore, the seepage levels on the logs represent the location of transient water seepage and may not indicate the static groundwater level. The stratification lines on the logs represent the approximate boundaries between soil types at the exploration locations. The actual transition between soil types may be gradual, and subsurface conditions can vary between exploration locations. The logs provide specific subsurface information only at the locations tested. The relative densities and moisture descriptions indicated on the test pit logs are interpretive descriptions based on the conditions observed during excavation. The compaction of backfill was not in the scope of our services. Loose soil will therefore be found in the area of the test pits. If this presents a problem, the backfill will need to be removed and replaced with structural fill during construction. CONCLUSIONS AND RECOMMENDATIONS GENERAL THIS SECTION CONTAINS A SUMMARY OF OUR STUDY AND FINDINGS FOR THE PURPOSES OF A GENERAL OVERVIEW ONLY. MORE SPECIFIC RECOMMENDATIONS AND CONCLUSIONS ARE CONTAINED IN THE REMAINDER OF THIS REPORT. ANY PARTY RELYING ON THIS REPORT SHOULD READ THE ENTIRE DOCUMENT. The test pits conducted for this study encountered medium dense native sands beneath a thin layer of loose fill and/or loose weathered soil. The depth to medium dense sands varied throughout the locations tested from about 1 foot up to 2.5 foot deep. The underlying competent, medium dense native sand is capable of supporting the proposed new building loads. However, to reduce the potential for differential settlement, the native sand soils beneath the footings should be densified using heavy compaction equipment such as a hydraulic hoe- pack or equivalent prior to pouring the footings. Also, the footings should be excavated using a smooth bucket to limit disturbance caused by teeth on a bucket. Overexcavation will be needed where the loose soils extend slightly deeper than planned footing elevations. The new footings could be lowered down to bear directly on GEOTECH CONSULTANTS, INC. Axthelm Construction. JN 16128 April 11, 2016 Page 3 the re-densified native soils or the resulting overexcavations could be restored to planned footing elevations with select, structural fill. The native sand could be used for this structural fill if placed in dry weather, and it is properly compacted in lifts. The underlying native sand soils are permeable. However, groundwater was encountered at approximately 3 to 5 feet during our investigation. Any stormwater infiltration design will need to account for the seasonal groundwater fluctuation and the relatively shallow groundwater table. Storm detention/retention facilities and other utilities are often installed below, or near, structures. The walls of storm vaults must be designed as either cantilever or restrained retaining walls, as appropriate. Wall pressures for the expected soil conditions are presented in the Permanent Foundation and Retaining Walls section of this report. It is important that the portion of the structure above the permanent detained water level be backfilled with free-draining soil, as recommended for retaining walls. Should drainage not be provided, the walls must be designed for hydrostatic forces acting on the outside of the structure. The backfill for all underground structures must be compacted in lifts according to the criteria of this report. Trenches for underground structures and utilities should not cross a line extending downwards from a new or existing footing at an inclination of 1:1 (Horizontal:Vertical), or a line extending downwards from a property line at an inclination of 1:1 (H:V). We should be consulted if these excavation zones will be exceeded for installation of storm facilities or other utilities. The shallow groundwater table must also be considered, as the wet sands will flow easily. We recommend including this report, in its entirety, in the project contract documents. This report should also be provided to any future property owners so they will be aware of our findings and recommendations. SEISMIC CONSIDERATIONS In accordance with the International Building Code (IBC), the site soil profile within 100 feet of the ground surface is best represented by Site Class Type D (Stiff Site Class). As noted in the USGS website, the mapped spectral acceleration value for a 0.2 second (Ss) and 1.0 second period (S1) equals 1.09g and 0.43g, respectively. The medium dense or denser native sands above the water table are not susceptible to seismic liquefaction, while sands beneath the water table are dense and would also not be considered at risk for seismic liquefaction. CONVENTIONAL FOUNDATIONS The proposed structures can be supported on conventional continuous and spread footings bearing on densified native sand soil, or on select structural fill placed above this competent native soil. We recommend that continuous and individual spread footings have minimum widths of 12 and 16 inches, respectively. Exterior footings should also be bottomed at least 18 inches below the lowest adjacent finish ground surface for protection against frost and erosion. The local building codes should be reviewed to determine if different footing widths or embedment depths are required. An allowable bearing pressure of 2,500 pounds per square foot (psf) is appropriate for footings supported on competent native soil or select structural fill placed above this competent soil. A one-third increase in this design bearing pressure may be used when considering short-term wind or seismic loads. For the above design criteria, it is anticipated that the total post-construction settlement of footings founded on competent native soil, or on structural fill up to 5 feet in thickness, will be about one-inch, with differential settlements on the order of one-half-inch in a distance of 75 feet along a continuous footing with a uniform load. Lateral loads due to wind or seismic forces may be resisted by friction between the foundation and the bearing soil, or by passive earth pressure acting on the vertical, embedded portions of the foundation. For the latter condition, the foundation must be either poured directly against relatively level, undisturbed soil or be GEOTECH CONSULTANTS, INC. Axthelm Construction. JN 16128 April 11, 2016 Page 4 surrounded by level, well-compacted fill. We recommend using the following ultimate values for the foundation's resistance to lateral loading: ULTIMATE PARAMETER VALUE Coefficient of Friction 0.45 Passive Earth Pressure 300 pcf Where: (i) pcf is pounds per cubic foot, and (ii) passive earth pressure is computed using the equivalent fluid density. We recommend maintaining a safety factor of at least 1.5 for the foundation's resistance to lateral loading, when using the above ultimate values. FOUNDATION AND RETAINING WALLS No significant foundation or retaining walls are anticipated. Even so, walls backfilled on only one side should be designed to resist the lateral earth pressures imposed by the soil they retain. The following recommended parameters are for walls that restrain level backfill: PARAMETER VALUE Active Earth Pressure * 35 pcf Passive Earth Pressure 300 pcf Coefficient of Friction 0.45 Soil Unit Weight 125 pcf Where: (i) pcf is pounds per cubic foot, and (ii) active and passive earth pressures are computed using the equivalent fluid pressures. * For a restrained wall that cannot deflect at least 0.002 times its height, a uniform lateral pressure equal to 10 psf times the height of the wall should be added to the above active equivalent fluid pressure. The design values given above do not include the effects of any hydrostatic pressures behind the walls and assume that no surcharges, such as those caused by slopes, vehicles, or adjacent foundations will be exerted on the walls. If these conditions exist, those pressures should be added to the above lateral soil pressures. Where sloping backfill is desired behind the walls, we will need to be given the wall dimensions and the slope of the backfill in order to provide the appropriate design earth pressures. Heavy construction equipment should not be operated behind retaining and foundation walls within a distance equal to the height of a wall, unless the walls are designed for the additional lateral pressures resulting from the equipment. The values given above are to be used to design only permanent foundation and retaining walls that are to be backfilled, such as conventional walls constructed of reinforced concrete or masonry. It is not appropriate to use the above earth pressures and soil unit weight to back-calculate soil strength parameters for design of other types of retaining walls, such as soldier pile, reinforced earth, modular or soil nail walls. We can assist with design of these types of walls, if desired. The values for friction and passive resistance are ultimate values and do not include a safety factor. We recommend a safety factor of at least 1.5 for overturning and sliding, when using the above values to design the walls. Restrained wall soil parameters should be utilized for a distance of 1.5 times the wall height from corners or bends in the walls. This is intended to reduce the amount of cracking that can occur where a wall is restrained by a corner. GEOTECH CONSULTANTS, INC. Axthelm Construction. JN 16128 April 11, 2016 Page 5 Wall Pressures Due to Seismic Forces The surcharge wall loads that could be imposed by the design earthquake can be modeled by adding a uniform lateral pressure to the above-recommended active pressure. The recommended surcharge pressure is 7H pounds per square foot (psf), where H is the design retention height of the wall. Using this increased pressure, the safety factor against sliding and overturning can be reduced to 1.2 for the seismic analysis. Retaining Wall Backfill Backfill placed behind retaining or foundation walls should be coarse, free-draining structural fill containing no organics. This backfill should contain no more than 5 percent silt or clay particles and have no gravel greater than 4 inches in diameter. The percentage of particles passing the No. 4 sieve should be between 25 and 70 percent. A drainage composite similar to Miradrain 6000 should be placed against the backfilled retaining walls, if the native sand is reused as wall backfill. The drainage composites should be hydraulically connected to the foundation drain system. Free-draining backfill or gravel should be used for the entire width of the backfill where seepage is encountered. For increased protection, drainage composites should be placed along cut slope faces, and the walls should be backfilled entirely with free-draining soil. The purpose of these backfill requirements is to ensure that the design criteria for a retaining wall are not exceeded because of a build-up of hydrostatic pressure behind the wall. Also, subsurface drainage systems are not intended to handle large volumes of water from surface runoff. The top 12 to 18 inches of the backfill should consist of a compacted, relatively impermeable soil or topsoil, or the surface should be paved. The ground surface must also slope away from backfilled walls to reduce the potential for surface water to percolate into the backfill. Water percolating through pervious surfaces (pavers, gravel, permeable pavement, etc.) must also be prevented from flowing toward walls or into the backfill zone. The compacted subgrade below pervious surfaces and any associated drainage layer should therefore be sloped away. Alternatively, a membrane and subsurface collection system could be provided below a pervious surface. It is critical that the wall backfill be placed in lifts and be properly compacted, in order for the above- recommended design earth pressures to be appropriate. The wall design criteria assume that the backfill will be well-compacted in lifts no thicker than 12 inches. The compaction of backfill near the walls should be accomplished with hand-operated equipment to prevent the walls from being overloaded by the higher soil forces that occur during compaction. The section entitled General Earthwork and Structural Fill contains additional recommendations regarding the placement and compaction of structural fill behind retaining and foundation walls. SLABS-ON-GRADE The building floors can be constructed as slabs-on-grade atop firm site soils, or on structural fill. Any existing fill material containing organics should be removed beneath slab areas. To limit differential settlement, the upper 12 inches of the slab subgrade should be compacted to 95% relative compaction prior to concrete placement. The subgrade soil must be in a firm, non-yielding condition at the time of slab construction or underslab fill placement. Any soft areas encountered should be excavated and replaced with select, imported structural fill. Even where the exposed soils appear dry, water vapor will tend to naturally migrate upward through the soil to the new constructed space above it. This can affect moisture-sensitive flooring, cause imperfections or damage to the slab, or simply allow excessive water vapor into the space above the slab. All interior slabs-on-grade should be underlain by a capillary break or drainage layer consisting of a minimum 4-inch thickness of gravel or crushed rock that has a fines content (percent passing the No. 200 sieve) of less than 3 percent and a sand content (percent passing the No. 4 sieve) of no more than 10 percent. GEOTECH CONSULTANTS, INC. Axthelm Construction. JN 16128 April 11, 2016 Page 6 As noted by the American Concrete Institute (ACI) in the Guides for Concrete Floor and Slab Structures, proper moisture protection is desirable immediately below any on-grade slab that will be covered by tile, wood, carpet, impermeable floor coverings, or any moisture-sensitive equipment or products. ACI also notes that vapor retarders, such as 6-mil plastic sheeting, have been used in the past, but are now recommending a minimum 10-mil thickness. A vapor retarder is defined as a material with a permeance of less than 0.3 perms, as determined by ASTM E 96. It is possible that concrete admixtures may meet this specification, although the manufacturers of the admixtures should be consulted. Where vapor retarders are used under slabs, their edges should overlap by at least 6 inches and be sealed with adhesive tape. The sheeting should extend to the foundation walls for maximum vapor protection. If no potential for vapor passage through the slab is desired, a vapor barrier should be used. A vapor barrier, as defined by ACI, is a product with a water transmission rate of 0.01 perms when tested in accordance with ASTM E 96. Reinforced membranes having sealed overlaps can meet this requirement. DRAINAGE CONSIDERATIONS Foundation drains should be used where (1) crawl spaces or basements will be below a structure, (2) a slab is below the outside grade, or (3) the outside grade does not slope downward from a building. Drains should also be placed at the base of all earth-retaining walls. These drains should be surrounded by at least 6 inches of 1- inch-minus, washed rock and then wrapped in non-woven, geotextile filter fabric (Mirafi 140N, Supac 4NP, or similar material). At its highest point, a perforated pipe invert should be at least 6 inches below the bottom of a slab floor or the level of a crawl space, and it should be sloped for drainage. All roof and surface water drains must be kept separate from the foundation drain system. For the best long-term performance, perforated PVC pipe is recommended for all subsurface drains. As a minimum, a vapor retarder, as defined in the Slabs-On-Grade section, should be provided in any crawl space area to limit the transmission of water vapor from the underlying soils. Also, an outlet drain is recommended for all crawl spaces to prevent a build up of any water that may bypass the footing drains. The excavations and site should be graded so that surface water is directed off the site and away from the tops of slopes. Water should not be allowed to stand in any area where foundations, slabs, or pavements are to be constructed. Final site grading in areas adjacent to buildings should slope away at least 2 percent, except where the area is paved. Surface drains should be provided where necessary to prevent ponding of water behind foundation or retaining walls. GENERAL EARTHWORK AND STRUCTURAL FILL All building and pavement areas should be stripped of surface vegetation, topsoil, organic soil, and other deleterious material. The stripped or removed materials should not be mixed with any materials to be used as structural fill, but they could be used in non-structural areas, such as landscape beds. Structural fill is defined as any fill, including utility backfill, placed under, or close to, a building, behind permanent retaining or foundation walls, or in other areas where the underlying soil needs to support loads. All structural fill should be placed in horizontal lifts with a moisture content at, or near, the optimum moisture content. The optimum moisture content is that moisture content that results in the greatest compacted dry density. The moisture content of fill is very important and must be closely controlled during the filling and compaction process. The allowable thickness of the fill lift will depend on the material type selected, the compaction equipment used, and the number of passes made to compact the lift. The loose lift thickness should not exceed 12 inches. We recommend testing the fill as it is placed. If the fill is not sufficiently compacted, it can be recompacted before another lift is placed. This eliminates the need to remove the fill to achieve the required compaction. The following table presents recommended relative compactions for structural fill: GEOTECH CONSULTANTS, INC. Axthelm Construction. JN 16128 April 11, 2016 Page 7 LOCATION OF FILL MINIMUM RELATIVE PLACEMENT COMPACTION Beneath footings, slabs 95% or walkways Filled slopes and 90% behind retaining walls 95% for upper 12 inches of Beneath pavements subgrade; 90% below that level Where: Minimum Relative Compaction is the ratio, expressed in percentages, of the compacted dry density to the maximum dry density, as determined in accordance with ASTM Test Designation D 1557-91 (Modified Proctor). Structural fill that will be placed in wet weather should consist of a coarse, granular soil with a silt or clay content of no more than 5 percent. The percentage of particles passing the No. 200 sieve should be measured from that portion of soil passing the three-quarter-inch sieve. LIMITATIONS The conclusions and recommendations contained in this report are based on site conditions as they existed at the time of our exploration and assume that the soil and groundwater conditions encountered in the test pits are representative of subsurface conditions on the site. If the subsurface conditions encountered during construction are significantly different from those observed in our explorations, we should be advised at once so that we can review these conditions and reconsider our recommendations where necessary. Unanticipated conditions are commonly encountered on construction sites and cannot be fully anticipated by merely taking samples in test pits. Subsurface conditions can also vary between exploration locations. Such unexpected conditions frequently require making additional expenditures to attain a properly constructed project. It is recommended that the owner consider providing a contingency fund to accommodate such potential extra costs and risks. This is a standard recommendation for all projects. This report has been prepared for the exclusive use of Axthelm Construction, and their representatives, for specific application to this project and site. Our conclusions and recommendations are professional opinions derived in accordance with current standards of practice within the scope of our services and within budget and time constraints. No warranty is expressed or implied. The scope of our services does not include services related to construction safety precautions, and our recommendations are not intended to direct the contractor's methods, techniques, sequences, or procedures, except as specifically described in our report for consideration in design. Our services also do not include assessing or minimizing the potential for biological hazards, such as mold, bacteria, mildew and fungi in either the existing or proposed site development. GEOTECH CONSULTANTS, INC. Axthelm Construction. JN 16128 April 11, 2016 Page 8 ADDITIONAL SERVICES In addition to reviewing the final plans, Geotech Consultants, Inc. should be retained to provide geotechnical consultation, testing, and observation services during construction. This is to confirm that subsurface conditions are consistent with those indicated by our exploration, to evaluate whether earthwork and foundation construction activities comply with the general intent of the recommendations presented in this report, and to provide suggestions for design changes in the event subsurface conditions differ from those anticipated prior to the start of construction. However, our work would not include the supervision or direction of the actual work of the contractor and its employees or agents. Also, job and site safety, and dimensional measurements, will be the responsibility of the contractor. During the construction phase, we will provide geotechnical observation and testing services when requested by you or your representatives. Please be aware that we can only document site work we actually observe. It is still the responsibility of your contractor or on-site construction team to verify that our recommendations are being followed, whether we are present at the site or not. The following plates are attached to complete this report: Plate 1 Site Exploration Plan Plate 2 Test Pit Logs Attachment Boring B-6 from Eagle Hardware We appreciate the opportunity to be of service on this project. If you have any questions, or if we may be of further service, please do not hesitate to contact us. Respectfully submitted, GEOTECH CONSULTANTS, INC. James H. Strange, Jr., P.E. Associate JHS: jhs GEOTECH CONSULTANTS, INC. N TP-1 TP-2 TP-3 TP-4 Legend - Approximate Test Pit Location Site Exploration Plan 16523 Smokey Point Boulevard Marysville, Washington 16128 Apr. 2016 1 GEOTECH CONSULTANTS, INC. TEST PIT (TP) 1 Depth (feet) Soil Description 0.0 â€“ 0.5 Crushed Rock 0.5 â€“ 1.0 Brown silty sand with brick debris, very moist, loose to medium-dense, [FILL] 1.0 â€“ 1.5 Reddish-brown mottled, silty SAND, fine- to medium-grained, moist, loose [SM] 1.5 â€“ 3.5 Tan, slightly silty SAND, fine- to medium-grained, very moist, medium-dense [SP/SM] 3.5 â€“ 5.5 Gray SAND with trace silt, fine- to medium-grained, very moist to wet, medium-dense [SP] - becomes dense at 4 feet. Test Pit was terminated at a depth of 5.5 feet on March 24, 2016. Groundwater seepage was observed at 5.0 feet. TEST PIT (TP) 2 Depth (feet) Soil Description 0.0 â€“ 0.5 Crushed Rock 0.5 â€“ 2.0 Dark brown remnant Topsoil very moist, very loose, [Topsoil] 2.0 â€“ 2.5 Reddish-brown mottled, silty SAND, fine- to medium-grained, moist, loose [SM] 2.5 â€“ 4.0 Tan, slightly silty SAND, fine- to medium-grained, very moist, medium-dense [SP/SM] 4.0 â€“ 6.0 Gray SAND with trace silt, fine- to medium-grained, wet, dense [SP] Test Pit was terminated at a depth of 6.0 feet on March 24, 2016. Groundwater seepage was observed at 4.0 feet. TEST PIT (TP) 3 Depth (feet) Soil Description 0.0 â€“ 0.5 Dark brown Topsoil very moist, very loose, [Topsoil] 0.5 â€“ 1.5 Reddish-brown mottled, silty SAND, fine- to medium-grained, moist, loose [SM] 1.5 â€“ 3.5 Tan, slightly silty SAND, fine- to medium-grained, very moist, medium-dense [SP/SM] 3.5 â€“ 5.0 Gray SAND with trace silt, fine- to medium-grained, wet, dense [SP] Test Pit was terminated at a depth of 5.0 feet on March 24, 2016. Groundwater seepage was observed at 4.0 feet. TEST PIT (TP) 4 Depth (feet) Soil Description 0.0 â€“ 0.5 Dark brown Topsoil very moist, very loose, [Topsoil] 0.5 â€“ 1.0 Reddish-brown mottled, silty SAND, fine- to medium-grained, moist, loose [SM] 1.0 â€“ 3.0 Tan, slightly silty SAND, fine- to medium-grained, very moist, medium-dense [SP/SM] 3.0 â€“ 4.5 Gray SAND with trace silt, fine- to medium-grained, wet, dense [SP] Test Pit was terminated at a depth of 4.5 feet on March 24, 2016. Groundwater seepage was observed at 3.0 feet. Note - Letters in brackets [ ] denote USCS soil designation. Test Pit Logs 16523 Smokey Point Boulevard Marysville, Washington 16128 Apr. 2016 2 GEOTECH CONSULTANTS, INC. GEOTECH CONSULTANTS, INC. TerraVista NW LLC Consulting Engineers July 31, 2019 Community and Economic Development City of Arlington 18204 59th Avenue NE Arlington, WA 98223 RE: Trailer Boss Development â€“ Proposed Traffic Mitigation This letter outlines the projectâ€™s proposed traffic mitigation. We believe the total PM Peak Hour Trips are less than 10 PHT, and therefore a formal traffic impact analysis study would not be required. The following outlines the projectâ€™s proposed traffic mitigation based on historical sales at other Trailer Boss facilities. The proposed Trailer Boss development will consist of a retail sales lot of utility trailers. Unlike car sales, trailer sales do not generate as much customer traffic, and most of the patrons visit the sales lots prior to the PM peak hours. The facility will have three staff that close business at 5:30. During the PM peak hours of 4-6 pm, up to 2 customers will typically visit the site, based on traffic observed at other Trailer Boss facilities. Current traffic mitigation rates for the City of Arlington are $3,355 per PMPHT. PMPHT are determined to be 5, which results in a total traffic mitigation fee of $16,775. The development will not impact WSDOT or Snohomish County collection projects and should therefore not be assessed WSDOT or Snohomish County traffic mitigation fees per the SEPA based interlocal agreements. Best Regards, Eric J. Scott, PE Principal 3204 Smokey Point Drive, Suite 207, Arlington WA 98223 LAND USE APPLICATION ZONING PERMIT COMMUNITY & ECONOMIC DEVELOPMENT 18204 59 Avenue NE ï‚· Arlington, WA 98223 ï‚· Main Line 360.403.3551 FOR AGENCY USE Date: File: Fee: $ PERMIT TYPE Type of Zoning Permit â˜ Binding Site Plan (< 9 lots) Required Submittals â˜ Auxiliary Sheet â˜ Boundary Line Adjustment (Check All That Apply) â˜ Shoreline Substantial â˜ Cottage (â‰¤19 Units) â˜ Design Review â€“ Admin. â˜ Design Review â€“ Board â˜ Forest Practice â˜ SEPA â˜ Multi-Family (â‰¤19 Units) â˜ Traffic â€“ City â˜ Short Plat Preliminary â˜ Traffic â€“ County â˜ Short Plat Final â˜ Traffic â€“ State â˜ Site Plan Review (<4 ac.) â˜ Special Event SITE INFORMATION Site Address Tax Parcel ID Number(s) (Use block # if no bldg. #) Acreage & Square Zoning Classification Footage Of Property Use Classification No. Water Supply Current Proposed Sewer Supply Current Proposed Existing Use of Property On-Site Critical Areas? Critical Area Type â˜ Yes â˜ No (e.g. wetland, steep slope, etc.) Has Site Been Logged in Will Site Be Logged as â˜ Yes â˜ No â˜ Yes â˜ No Past 6 years? Part of This Project? OWNER APPLICANT CONTACT Name Full Address Phone Number E-mail Relationship of Applicant â˜Owner â˜Contract Purchaser â˜Lessee â˜Other: to Property (check one) PROJECT ARCHITECT PROJECT ENGINEER PROJECT SURVEYOR Name Full Address Phone Number E-mail Zoning Permit Application City of Arlington Page 1 of 3 Rev 01/2017 PRELIMINARY SHORT PLAT & BINDING SITE PLAN APPLICATION ONLY Project / Plat Name Total No. of Proposed Lots Total Number of Proposed Units Single Family Two Family By Dwelling / Multi-Family Use Type Commercial Industrial Has this property been subdivided, or has application for subdivision been â˜ Yes â˜ No made, within the last 5 years? If Yes, Provide Applicant Name & Plat Name FINAL SHORT PLAT APPLICATION ONLY Date Preliminary Plat Approved Improvements have been: â˜ Built â˜ Bonded â˜Some Built, Some Bonded â˜Other: SHORELINE DEVELOPMENT ONLY (Required for all Development Within or Adjacent to a Shoreline) Will this Proposal be a Substantial Development as Defined in AMC Â§20.92.010? â˜ Yes â˜ No Shoreline Environmental Designation (if yes) Are you requesting a Shoreline Variance as allowed under AMC Â§20.92.130? â˜ Yes â˜ No FOREST PRACTICE (For Clearing >10,000sf) AND MITIGATION FOR SIGNIFICANT TREE REMOVAL (All Applications) Associated Land Use Permit â„– Number of Significant Trees to be Harvested Total Acreage to be Harvested Is there a Current Development Moratorium on the Site? â˜ Yes â˜ No Type of Forest Land Conversion â˜ Class IV â€“ General â˜ Class IV â€“ Special ______________ Significant Tree Mitigation Options (A, B, or C) Will Significant Trees be Removed During any Phase of this Proposed Project? â˜ Yes â˜ No A) Number of Trees to be Replanted On-Site (3:1 Ratio) OR Date Completed (For Agency Use Only) B) Number of Trees to be Replanted Off-Site (3:1 Ratio) Location: OR Date Completed (For Agency Use Only) C) Tree Mitigation In-Lieu Fee (# of Harvested Trees) ______ X (3) X (Tree Cost) = _______ Date Paid Receipt â„– Zoning Permit Application City of Arlington Page 2 of 3 Rev 01/2017 AUXILIARY SHEET SITE PLAN REVIEW ZONING PERMIT 18204 59 Avenue NE ï‚· Arlington, WA 98223 ï‚· Main Line 360.403.3551 Office Hours: Monday â€“ Friday 8AM to 5PM (Closed Holidays) INSTRUCTIONS Table I below is a checklist of items that must be submitted as part of your zoning permit application for a site plan review. Table II below outlines the minimum information that must be provided on your plan sheets. Numbers in parenthesis equal the number of copies required. Please use only paper clips and/or binder clips when assembling documents. All Boundary and Topographic Surveys must be prepared byâ€”or under the supervision ofâ€”a professional land surveyor registered in the State of Washington. If you have any questions about what is required, or if you would like to schedule a pre-application meeting, please call our department main line listed above. No appointment is necessary for application submittal but it is highly encouraged. TABLE I - CHECKLIST â˜ (1) CD-R with Individual PDFs of Each Item Listed Below â†“ â˜ (1) Vicinity Map (on 8Â½â€ X 11â€) â˜ (1) Written Narrative (Description of Proposal) SITE PLANS (see Table II) â˜ (2) Full Size â˜ (2) 11â€ X 17â€ LANDSCAPE PLANS (see Table II) â˜ (2) Full Size â˜ (2) 11â€ X 17â€ TREE SURVEY, IF REQUIRED (see AMC 20.76.120) â˜ (2) Full Size â˜ (2) 11â€ X 17â€ REPORTS â˜ (2) Traffic Impact Analysis â˜ (2) Stormwater Drainage Report â˜ (2) Wetland Study, If Required â˜ (2) Geotechnical Report, If Required â˜ (2) SEPA Checklist UTILITY â˜ (1) Utility Service Availability Letter â€“ City of Arlington; OR â˜ (1) Utility Service Availability Letter â€“ City of Marysville Auxiliary Sheet - Site Plan Review City of Arlington Page 1 of 3 Rev 01/2017 TABLE II â€“PLAN SHEET REQUIREMENTS COVER SHEET â˜ Title Block (centered at top of drawing) that includes the following: City of Arlington Name of Proposed Development File No. (call for correct number) Section, Township, & Range â˜ Site Information: Site Address (use block # if no bldg. #) Zoning Classification Airport Protection District Subdistrict Use Classification Density & Dimensional Calculations Lot(s) Size (both in acreage and square feet) Lot Dimensions (length, width) and Numbers/Letters Proposed Residential Density (if applicable) Building Setback (for existing, proposed, & relocated bldgs. on site) Building Height (for existing, proposed, & relocated bldgs. on site) Total Lot Coverage (Impervious Surface) Recreational & Open Space Calculations (if applicable) Adjacent Street Names & Classifications Required Parking Space Calculations (required & proposed) Screening Types Provided (indicate for each lot line) Utility Provider (Sewer & Water) Critical Area Types Located On-Site (If Applicable) Shoreline Classification (If Applicable) â˜ Sheet Index â˜ Date Plans Were Prepared â˜ Vicinity Map (Include North Arrow, Scale, and pinpoint site location) â˜ Name, Address, Phone Number, & Email Address of the Applicant, Owner, Engineer, & Landscape Architect SITE PLAN SHEET â˜ Title Bar (locate along right edge of sheet) that includes the following: Date Drawing was Prepared or Revised Project Name & Location Name, Address, & Phone Number of Applicant, Owner, Engineer, & Surveyor â˜ Existing Lot Lines Within or Adjacent to the Project Site â˜ Existing and Proposed Rights-of-Way (include dimensions & street name) â˜ Existing and Proposed Easements (include dimensions) â˜ Existing Critical Area Boundaries and Associated Buffers On-Site and Within 150ft. of Site â˜ Building (whether proposed, expanded, retained, or relocated) Setbacks From All Lot Lines â˜ Building (whether proposed, expanded, retained, or relocated) Dimensions and Square Footage â˜ Building Elevations (all sides for proposed or expanded buildings only â€“ color renderings preferred) â˜ Parking Stall, Loading Stall, Driveway, & Isle Locations & Dimensions â˜ Refuse Bin Location (including screening details) â˜ Lighting Details (building exterior, site, & parking area) â˜ Site Ingress/Egress (existing and/or proposed) â˜ Frontage Improvements with Dimensions (if required) Auxiliary Sheet - Site Plan Review City of Arlington Page 2 of 3 Rev 01/2017 LANDSCAPE PLAN SHEET â˜ Plant Schedule and Legend Showing Scientific and Common Names for Each Type of Tree, Shrub, and Ground Cover and their Quantity, Planting Size Mature Size, and Symbol. â˜ Tree, Shrub, and Lawn Planting Details â˜ Location and Spacing of All Trees, Shrubs, and Plants (including existing trees to be preserved) â˜ Irrigation Details (if required) â˜ Parking Area Shading Calculation (see AMC 20.76.130) â˜ Dimensions for Each Landscape Area, Including Frontage, Lot Boundary, and Vehicle Accommodation Area Landscaping Auxiliary Sheet - Site Plan Review City of Arlington Page 3 of 3 Rev 01/2017 Civil File Checklist Performance Bond Required: ________ Amount: ____________________________________________________________ Describe: _______________________________________________________________________________________________________ Maintenance Bond Required: ________ Amount: ____________________________________________________________ Describe: _______________________________________________________________________________________________________ As-built required: ________ Bill of Sale required: _______ W / S / SS ROW Permit: ________________ ROW Dedication: ______ AFN: ____________________________ Easement: _______ AFN: __________________________ Action Date Comments Sent Notes Intake Submittal 2nd Round Submittal 3rd Round Submittal Performance Bond Request Performance Bond Received Material Submittals Contractor Business License Contractor Proof of Insurance DOE Stormwater Permit CESCL ROW Permit Issued Construction Plans Approved Pre-Construction Meeting No As-built Review Construction Complete Easement/Dedication Required Request CAD File Send PDFâ€™s & CAD to GIS Maintenance Bond Request Maintenance Bond Received Performance Bond Released As-built Review Construction Complete Easement/Dedication Required As-built Review/Bills of Sale Dedications/Easements Draft As-built Resubmittal As-built Plans Signed Request AutoCAD Files Dedications/Easements Recorded Prepare Bills of Sale for Notary Final Bill of Sales to Finance & GIS Send PDFâ€™s & CAD to GIS Maintenance Bond Released Page | 1 7/17REV Civil File Checklist Page | 2 7/17REV 18204 59th Avenue NE REVIEW COMMENT FORM Arlington, WA 98223 360-403-3551 Project Name: Trailer Boss Permit No.: PWD-2024 Review Date: 2-14-2020 Contact: Eric Scott Email: erics@terravistanw.com Review Phase: Civil Report Date: Reviewing Dept.: CED Applicant: Eric Scott DWG Issue Date: # Rev. Dwg. or Addâ€™l Ref. City Comment Response/Resolution Spec. Ref. Approved 1. NEH A Stormwater General Permit is Required 2. NEH A CESCL needs to be specified prior to scheduling the pre-construction meeting 3. NEH Survey Map The three easements on the Survey Map are unclear. Specifically the larger easement to the north. Does it cover the remainder of the property from the line to the north? Please clarify 4. NEH C1.2 Clarify â€œUnless Notes Otherwiseâ€ as the notes do apply, even if a note says otherwise somewhere. 5. NEH Provide a temporary construction easement for the south adjacent property grading 6. NEH SWPPP Call out protections to prevent over compacting or siltation for the infiltration trenches 7. NEH L1.1 Provide shading in the parking area around the office 8. NEH Provide the tie-in location of the building downspouts for both buildings 9. NEH C2.4 Provide 20â€™ minimum setback for the infiltration trench from the building 10. NEH C2.4 Provide 10â€ minimum setback for the infiltration trenches along the property lines 11. NEH Drainage Fill in the numbers and complete the math for the Report structure table slope for the storm perf pipes 12. NEH Drainage The Drainage Report must discuss infiltration rate, how it Report was determined, and the different rates onsite from the testing. Include the depth of the test pit compared to actual depth of the proposed infiltration bottom. In appears 10in/hr was used, but the Geotechnical Report recommends 2in/hr for the site (10in/hr is for a very specific region and soil). See page 7 of the Geotechnical Page 1 of 1 18204 59th Avenue NE REVIEW COMMENT FORM Arlington, WA 98223 360-403-3551 Project Name: Trailer Boss Permit No.: PWD-2024 Review Date: 2-14-2020 Contact: Eric Scott Email: erics@terravistanw.com Review Phase: Civil Report Date: Reviewing Dept.: CED Applicant: Eric Scott DWG Issue Date: # Rev. Dwg. or Addâ€™l Ref. City Comment Response/Resolution Spec. Ref. Approved Report and be very specific in your report body explaining those recommendations and how your design meets it. 13. NEH Drainage Explain regarding gourndwater elevations compared to Report trench bottom elevations. 14. NEH Drainage Because of the way the WWHM work was done, provide Report listed out a total volume and bottom area needed for the entire site based on the model. Then provide the breakdown for each trench, volume and infiltration area. Then total together all proposed areas and volumes to show what is actually provided for the site. 15. NEH Drainage Identify and fix any defects in existing sidewalk to be Report current with ADA Standards 16. NEH Provide Dumpster location 17. NEH Provide a bike rack, could be placed in the planter strip Page 2 of 1 NW 28 T31N R 5E LLC SITE Consulting Engineers TerraVista NW GENERAL INFORMATION TRAILER BOSS C1.1 Plotted: Mar 06, 2020 - 1:18pm Rodney T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C1.1 GEN INFO NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW â€œ â€ GENERAL NOTES TRAILER BOSS C1.2 Plotted: Mar 06, 2020 - 1:18pm Rodney T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C1.2-GEN NOTES NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW â€™ SWPPP NOTES TRAILER BOSS C1.3 Plotted: Mar 06, 2020 - 1:19pm Rodney T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C1.3-SWPPP NOTES NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW 0 30 60 SWPPP TRAILER BOSS Scale in Feet C2.1 Plotted: Mar 06, 2020 - 1:19pm Rodney T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C2.1-SWPPP NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW 0 30 60 Scale in Feet PAVING PLAN TRAILER BOSS C2.2 Plotted: Mar 06, 2020 - 1:19pm Rodney T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C2.2 PAVING PLAN NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW 0 30 60 Scale in Feet GRADING PLAN TRAILER BOSS C2.3 Plotted: Mar 06, 2020 - 1:19pm Rodney T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C2.3-GRAD PLAN NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW 0 30 60 Scale in Feet DRAINAGE PLAN TRAILER BOSS C2.4 Plotted: Mar 06, 2020 - 1:19pm Rodney T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C2.4-SD PLAN NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW SWPPP DETAILS TRAILER BOSS C3.1 Plotted: Mar 06, 2020 - 1:19pm Rodney T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C3.1-SWPPP DETAILS NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW PAVING DETAILS TRAILER BOSS C3.2 Plotted: Mar 06, 2020 - 1:19pm Rodney T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C3.2-PAVE DETAILS NW 28 T31N R 5E LLC Consulting Engineers TerraVista NW STORM DRAINAGE DETAILS TRAILER BOSS C3.4 Plotted: Mar 06, 2020 - 1:19pm Rodney T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: C3.4-SD DET NW 28 T31N R 5E 0 30 60 Scale in Feet LLC Consulting Engineers TerraVista NW LANDSCAPE PLAN TRAILER BOSS L1.1 Plotted: Mar 06, 2020 - 1:19pm Rodney T:\Projects\190403 Trailerboss (Arlington)\Plans\TB_P-CIVIL.dwg Layout Name: L1.1-LANDSCAPE Stormwater Management Report March 6, 2020 Trailer Boss Development Prepared for: Fine Family Trust 3030 137th Lane SW Tenino, WA 98589 (360) 508-9583 Prepared by: 3/6/2020 TerraVist a NW LLC Consulting En gineers 3204 Smokey Point Dr., www.TerraVistaNW.com Suite 207 (425) 422-0840 Arlington, WA 98223 TerraVista NW,LLC Stormwater Management Report Table of Contents Stormwater Management Report.......................................................................................................................1 Project Overview............................................................................................................................................2 Site Location..............................................................................................................................................2 Code Compliance.......................................................................................................................................2 Executive Summary.......................................................................................................................................3 Pervious/Impervious Areas............................................................................................................................3 Onsite Pervious / Impervious Area............................................................................................................4 Soils................................................................................................................................................................3 Minimum Stormwater ManagementRequirements.......................................................................................3 Overview of Minimum Requirements........................................................................................................5 1-Preparation of Stormwater Site Plans.....................................................................................................6 2-Construction Stormwater Pollution Prevention Plan (SWPPP)..............................................................6 3-Source Control of Pollution....................................................................................................................6 4-Preservation of Natural Drainage Systems and Outfalls.........................................................................6 5-Onsite Stormwater Management.............................................................................................................7 6-Runoff Treatment....................................................................................................................................9 7-Flow Control...........................................................................................................................................9 8-Wetland Protection..................................................................................................................................9 9-Operation and Maintenance....................................................................................................................9 Appendix A â€“ Stormwater Pollution Prevention Plan Appendix B â€“ Soils Report Appendix C â€“ Operation and Maintenance Appendix D â€“Infiltration Trench Drainage Calculations (190403)Trailer Boss Page1 March 3, 2020 TerraVista NW,LLC Stormwater Management Report Project Overview Site Location The project is locatedat the corner of Smokey Point Blvd and 166th Pl on a 2.28 acre site. Code Compliance The project will comply with: Â· [WSDOT] STANDARD SPECIFICATIONS for ROAD, BRIDGE and MUNICIPAL CONSTRUCTION, WSDOT, 2018 Editionwith amendments Â· [ADCS] Arlington Design and Construction Standards, dated July 2008 Â· [AMC] Arlington Municipal Code Â· [SWMMWW] 2012/14 Stormwater Management Manual for Western Washington (190403)Trailer Boss Page2 March 3, 2020 TerraVista NW,LLC Stormwater Management Report Executive Summary The proposed project will be a developing of a retail sales site for utility trailers. The project site is made up of two parcels totaling 2.28 acres combined. An office building will be placed next to Smokey Point Blvd and a maintenance shop will be placed in the back of the facility. 10 parking stalls will be provided for staff and customers, and the remaining portions of the site will be used for product display of utility trailers. The site will also include require landscaping. Stormwater mitigation will be addressed though infiltration facilities. The ground water elevation is fairly high at this location, therefore the site will be raised to provide the required separation between infiltration and groundwater table. Existing Conditions The existing site is currently cleared of all vegetation. The front half of the site is gravel while the back half is exposed soil. Smokey Point Blvd borders the site on the west, 166th Place borders the site on the north, the Snohomish County PUD substation borders the east side, and a vacant lot borders the south side. Soils The test pits conducted for this study encountered native silty sands and sands beneath a thin layer of fill soil or topsoil. Underlying the fill and/or topsoil, we observed weathered silty sand soils that were loose. The fill and weathered soil was approximately 1 to 2.5 feet deep, and beneath these soils tan, medium dense, native, slightly silty sand was encountered. Beneath the tan sands, we encountered dense, gray sand that extended to the bottom of all of the pits (6 footmax explored depth at the site). This sand soil is typical for the native conditions encountered in the general vicinity. Based on the soil explorations performed by Materials Testing and Consulting(MTC), groundwater was encountered approximately 5-7â€™ below grade, depending on the location. The elevation of the groundwater table at the time of exploration wasextrapolated to be approximately elevation 113â€™, based on the depth measurements and the ground elevation at the test pit locations. MTC determined two different long-term design infiltration rates dependent upon the depth in the soil column.Soils at depths between 2.0â€™ and 3.0â€™ were determined to have an infiltration rate of 2 in/hr. Soils at depths of 4.0â€™ and greater were determined to have an infiltration rate of 10 in/hr. Refer to soils report in Appendix B for additional information. Proposed Conditions The proposed project will be a developing of a retail sales site for utility trailers. The project site is made up of two parcels totaling 2.28 acres combined. An office building will be placed next to Smokey Point Blvd and a maintenance shop will be placed in the back of the facility. 10 parking stalls will be provided for staff and customers, and the remaining portions of the site will be used for product display of utility trailers. The site will also include require landscaping. Stormwater facilities will utilize infiltration. Due to the high groundwater elevation a mounding analysis hasbeen performed.The lowest infiltration trench bottom elevation is at 115.5â€™ (2.5â€™ above the averagegroundwater table). All infiltration trench bottoms are within the zone reported by the geotechnical report to have an infiltration rate of 10 in/hr. (190403)Trailer Boss Page3 March 3, 2020 TerraVista NW,LLC Stormwater Management Report Pervious/Impervious Areas Refer to Figure 1 for agraphical depiction of tributary areas. For use in determining stormwater mitigation fees the following areas represent the true pervious/impervious area for the entire site. Onsite Pervious / Impervious Area Total impervious surfaceâ€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦..â€¦â€¦â€¦..â€¦2.03 ac Total pervious surfaceâ€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦..â€¦â€¦â€¦â€¦â€¦.â€¦..0.25 ac TOTAL ONSITE AREAâ€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦..â€¦â€¦â€¦â€¦â€¦â€¦â€¦..2.28 ac (190403)Trailer Boss Page4 March 3, 2020 TerraVista NW,LLC Stormwater Management Report Minimum Stormwater Management Requirements Overview of Minimum Requirements Minimum requirements 1-9 shall apply to the project. (190403)Trailer Boss Page5 March 3, 2020 TerraVista NW,LLC Stormwater Management Report 1-Preparation of Stormwater Site Plans Stormwater site plans were prepared in accordance with Volume I, Chapter 3 of the SWMMWW. 2-Construction Stormwater Pollution Prevention Plan (SWPPP) A SWPPP narrative has been prepared and is included in Appendix A and on the plan set. The erosion potential for the site is very low to non-existent. The onsite soils are highly infiltratable so no runoff during construction is anticipated. 3-Source Control of Pollution The project will not pose any source of pollution for the site other than concrete for the building foundations. The site is not considered a high use site. The SWPPP provided will address the source control of pollution during the construction phase. 4-Preservation of Natural Drainage Systems and Outfalls Existing regionaldrainageinfiltrates into the soils. Proposed drainagesystemwill alsoinfiltrate, therefore, preservation of natural drainage systems and outfall is being met. (190403)Trailer Boss Page6 March 3, 2020 TerraVista NW,LLC Stormwater Management Report 5-Onsite Stormwater Management (190403) Trailer Boss Page 7 March 3, 2020 TerraVista NW,LLC Stormwater Management Report A Drainage Summary Sheet and Figure 1 are enclosed detailing the parameters of each drainage system. All drainage systems are designed to infiltrate 100% of the stormwater therefore meeting and exceeding the LID stormwater requirements including other minimum requirements. Detailed drainage calculations for onsite and offsite facilities are provided in the appendices. As each drainage facility is essentially identical to each other in function and calculation methodology, a single gravel infiltration trench was modeled as the basis of the design. Each drainage system onsite was determined based on a proration of the modeled facility. For ease of calculation, the model area was 2.28-acre with a facility thickness of 2â€™ of drain rock. The model determined that the required size of any infiltration trench/mat for this project would need to be 2,303sf/acre of tributary area. As shown in the attached Drainage Summary Sheet, 2,303 sf/acre was divided by the proposed width of each tributary area to determine the required minimum length of the individual facility. The WWHM model determined that a total of 5,250 sf of infiltration area was required to fully infiltrate the 2.28-acre site. The project design provides 5,288 sf of infiltration area. SSC-4 of the SWMMWW requires that infiltration facilities that are utilized for treatment purposes must document that the water quality design storm volume (indicated by WWHM or MGS Flood, or runoff from a 6-month, 24-hour rain event) can infiltrate through the infiltration basin surface within 48 hours. The infiltrationfacilities are designed to infiltrate 100% of the stormwater within the 2â€™ depth of the storage layer. The water quality storm, which is less than the all storms contained within the model, will also be contained within the 2â€™ storage layer of the infiltration trench. SSC-4 is therefore met. Upstream Analysis The surrounding area has flat topography with high infiltration soils. No stormwater from offsite areas are anticipated to flow onto the project site. Downstream Analysis The proposed storm drain mitigation for the project site will infiltrate 100% of the stormwater. Therefore, no impacts to the downstream system are anticipated. In the event that onsite drainage systems are overwhelmed by excessive rainfall, the stormwater will primarilycontinue to stay onsite due to the topography of the site, with the exception of the south- western property line adjacent to the residential property. In the event the storm system is overwhelmed, some amount of water may spill over into the side yard of the residence. Overall, stormwater will not back up into the buildings. (190403)Trailer Boss Page8 March 3, 2020 TerraVista NW,LLC Stormwater Management Report BMP T5.13: Post-Construction Soil Quality and Depth BMP T5.13 is required as part of Minimum Requirement #5. Although the Contractor has the option of stockpiling existing topsoil material, itis anticipated that the Contractor will import topsoil material to meet the requirements of BMP T5.13. 6-Runoff Treatment The site will meet the basic level of treatment, as the project does not meet the thresholds for enhanced treatment, phosphorousremoval, or oil treatment as described in Section V-3 of the SWMMWW. Pollutant generating impervious areas (PGIS) will drain to a series of infiltration trenches that utilize an 18â€ layer of sand for filtration, as the existing soils do not meet the site suitability requirements of SSC- 6. The sand layer will be below the gravel infiltration trench. The system is similar to that used by permeable pavements for treatment, as part of BMP T5.15, whereby stormwater passes through a gravel storage layer, followed by a sand layer, and then final infiltration into the native soil. Pretreatment for the infiltration systems in the middle of the site will include the use of sand/oil water separators at each catch basin, in accordance with the Cityâ€™s standard detail SD-120. Pretreatment for the linear â€œFrench Drainâ€ system along the property lines will include a sump to capture sediment, as well as a surface gravel layer to trap sediment before entering the system. 7-Flow Control This is being met with 100% infiltration of the stormwater onsite. 8-Wetland Protection No wetlands are present on the site or within the adjacent downstream area. 9-Operation and Maintenance Operation and maintenance procedures are included in AppendixC. (190403)Trailer Boss Page9 March 3, 2020 FIGURE 1 â€“ TRIBUTARY AREAS Drainage Information Summary Project Name: Trailer Boss Development Onsite Project Total Area: 2.28 acres Offsite Project Total Area: 0.18 acres Number of Lots (if applicable): 2 Infiltration Proration 2,303 sf/acre @ 2' depth (Note: For conservatism, subbasins were modeled as 100% imperv.; parking subbasins were modeled as 100% pollutant generating) Drainage Basin Information Total Area of Impact 0.05 0.65 0.01 0.52 0.42 0.07 0.39 0.17 2.28 Existing Condition Area (ac) Pervious Area 0.05 0.42 0.07 0.39 0.17 1.1 Impervious Area 0.65 0.01 0.52 1.18 Proposed Condition Area (ac) Pervious Area Impervious Area Non-pollution Generating 0.05 0.04 0.01 0.1 Pullution Generating 0.61 0.52 0.42 0.07 0.39 0.17 2.18 Infiltration Facility Sizing (prorated) Thickness (ft) 2 2 2 2 2 2 2 Width (ft) 2.0 5.0 5.5 4.5 2.0 5.5 4.0 Min Length (ft) 58 299 218 215 81 163 97 Pre-developed Runoff Rates Q (cfs) 2 Year 10 year 100 year Post-developed Runoff Rates Q (cfs) 2 Year 10 year 100 year Offsite Upstream Area 0 0 0 0 0 0 0 0 Type of Storage Proposed Infilt. Infilt. NA Infilt. Infilt. Infilt. Infilt. Infilt. Approx. Storage Volume (cu-ft) NA NA NA NA NA NA NA NA Type of Treatment NA Sand NA Sand Sand Sand Sand Sand Low Impact Development Yes Yes NA Yes Yes Yes Yes Yes TerraVista NW,LLC Appendix A Construction Stormwater Pollution Prevent Plan (SWPPP) Construction Stormwater General Permit (CSWGP) Stormwater Pollution Prevention Plan (SWPPP) for Trailer Boss Prepared for: Department of Ecology Northwest Region Permittee / Owner Developer Operator / Contractor Trailer Boss Same Pending [Insert Project Site Location] Update as necessary. Certified Erosion and Sediment Control Lead (CESCL) Name Organization Contact Phone Number Pending Pending Pending SWPPP Prepared By Name Organization Contact Phone Number Eric Scott TerraVista NW 425-422-0840 SWPPP Preparation Date Month / Day / Year Project Construction Dates Activity / Phase Start Date End Date Construction March 2020 Aug 2020 List of Acronyms and Abbreviations Acronym / Abbreviation Explanation 303(d) Section of the Clean Water Act pertaining to Impaired Waterbodies BFO Bellingham Field Office of the Department of Ecology BMP(s) Best Management Practice(s) CESCL Certified Erosion and Sediment Control Lead CO2 Carbon Dioxide CRO Central Regional Office of the Department of Ecology CSWGP Construction Stormwater General Permit CWA Clean Water Act DMR Discharge Monitoring Report DO Dissolved Oxygen Ecology Washington State Department of Ecology EPA United States Environmental Protection Agency ERO Eastern Regional Office of the Department of Ecology ERTS Environmental Report Tracking System ESC Erosion and Sediment Control GULD General Use Level Designation NPDES National Pollutant Discharge Elimination System NTU Nephelometric Turbidity Units NWRO Northwest Regional Office of the Department of Ecology pH Power of Hydrogen RCW Revised Code of Washington SPCC Spill Prevention, Control, and Countermeasure su Standard Units SWMMEW Stormwater Management Manual for Eastern Washington SWMMWW Stormwater Management Manual for Western Washington SWPPP Stormwater Pollution Prevention Plan TESC Temporary Erosion and Sediment Control SWRO Southwest Regional Office of the Department of Ecology TMDL Total Maximum Daily Load VFO Vancouver Field Office of the Department of Ecology WAC Washington Administrative Code WSDOT Washington Department of Transportation WWHM Western Washington Hydrology Model Project Information (1.0) Project/Site Name: Trailer Boss Street/Location: Smokey Point Blvd City: Arlington State: WA Zip code: 98223 Subdivision: Receiving waterbody: Groundwater Existing Conditions (1.1) Total acreage (including support activities such as off-site equipment staging yards, material storage areas, borrow areas). Total acreage: 2.28 acres Disturbed acreage: 2.28 acres Existing structures: None Landscape topography: Flat Drainage patterns: Infiltration Existing Vegetation: None Critical Areas (wetlands, streams, high erosion risk, steep or difficult to stabilize slopes): None List of known impairments for 303(d) listed or Total Maximum Daily Load (TMDL) for the receiving waterbody: None Table 1 includes a list of suspected and/or known contaminants associated with the construction activity. List all known or suspected contaminants associated with this site in Table 1. Include contaminants previously remediated. Table 1 â€“ Summary of Site Pollutant Constituents Constituent (Pollutant) Location Depth Concentration None [Insert Text] [Insert Text] [Insert Text] Proposed Construction Activities (1.2) Description of site development (example: subdivision): Commercial Development Description of construction activities (example: site preparation, demolition, excavation): Site preparation, demolition, excavation and fill, paving, and building construction Description of site drainage including flow from and onto adjacent properties. Must be consistent with Site Map in Appendix A: Stormwater drainage will utilize infiltration trenches to infiltrate 100% of the stormwater. Description of final stabilization (example: extent of revegetation, paving, landscaping): Site will be paved as well as gravel within landscape areas. Contaminated Site Information: Proposed activities regarding contaminated soils or groundwater (example: on-site treatment system, authorized sanitary sewer discharge): NA Construction Stormwater Best Management Practices (BMPs) (2.0) Describe the BMPs identified to control pollutants in stormwater discharges. Depending on the site, multiple BMPs for each element may be necessary. For each element identified: Â· Clearly describe the control measure(s). Â· Describe the implementation sequence. Â· Describe the inspection and maintenance procedures for that specific BMP. Â· Identify the responsible party for maintaining BMPs (if your SWPPP is shared by multiple operators, indicate the operator responsible for each BMP). Categorize each BMP under one of the following elements as listed below: 1. Preserve Vegetation / Mark Clearing Limits 2. Establish Construction Access 3. Control Flow Rates 4. Install Sediment Controls 5. Stabilize Soils 6. Protect Slopes 7. Protect Drain Inlets 8. Stabilize Channels and Outfalls 9. Control Pollutants 10.Control Dewatering 11.Maintain BMPs 12.Manage the Project 13.Protect Low Impact Development Â· BMPs must be consistent with the most current approved edition of the Stormwater Management Manual for Western Washington (SWMMWW) at sites west of the crest of the Cascade Mountains; the Stormwater Management Manual for Eastern Washington (SWMMEW) for sites east of the crest of the Cascade Mountains at the time the general permit was issued; or other Ecology-approved manual. Â· Note the location of each BMP on your Site Map in Appendix A. Â· Include the corresponding Ecology source control BMPs and runoff conveyance and treatment BMPs in Appendix B. o SWMMWW Volume II Chapter 4 Sections 4.1 and 4.2 â€“ https://fortress.wa.gov/ecy/publications/SummaryPages/1410055.html or o SWMMEW Chapter 7 Section 7.3.1 and 7.3.2 â€“ https://fortress.wa.gov/ecy/publications/summarypages/0410076.html o If it can be justified that a particular element does not apply to the project site, include a written justification in lieu of the BMP description in the text for the appropriate element. The SWPPP is a living document reflecting current conditions and changes throughout the life of the project. These changes may be informal (i.e. hand-written notes and deletions). Update the SWPPP when the CESCL has noted a deficiency in BMPs or deviation from original design. The 12 Elements (2.1) Element 1: Preserve Vegetation / Mark Clearing Limits (2.1.1) Describe the methods (signs, fences, etc,) you will use to protect those areas that should not be disturbed. Describe natural features identified and how each will be protected during construction. Trees that are to be preserved, as well as all sensitive areas and their buffers, shall be clearly delineated, both in the field and on the plans. Describe how natural vegetation and native topsoil will be preserved. List and describe BMPs: BMP C103 â€“ High Visibility Fence, BMP C233-Silt Fence Installation Schedules: Installed prior to ground breaking Inspection and Maintenance plan: Inspected weekly and after major precipitation event Responsible Staff: CESCL Element 2: Establish Construction Access (2.1.2) Describe how you will minimize dust generation and vehicles tracking sediment off-site. Limit vehicle access to one route, if possible. Recycled concrete used to establish construction ingress or egress may be a stormwater pollutant source that requires treatment prior to discharge. Street sweeping, street cleaning, or wheel wash/tire baths may be necessary if the stabilized construction access is not effective. All wheel wash wastewater shall be controlled on-site and CANNOT be discharged into waters of the State. Install site ingress/egress stabilization BMPs according to BMP C105. Describe how you will clean the affected roadway(s) from sediment which is tracked off-site. List and describe BMPs: BMP C105-Stabilized Construction Entrance Installation Schedules: installed at the start of construction Inspection and Maintenance plan: Inspected and maintained weekly or after significant rainfall event Responsible Staff: CESCL Element 3: Control Flow Rates (2.1.3) Describe how you will protect properties and waterways downstream of the project from increased speed and volume of stormwater discharges due to construction activity. Construction of stormwater retention and/or detention facilities must be done as one of the first steps in grading. Assure that detention facilities are functioning properly before constructing site improvements (i.e. impervious surfaces). If applicable, describe how you will protect areas designed for infiltration from siltation during the construction phase. Will you construct stormwater retention and/or detention facilities? Yes No Will you use permanent infiltration ponds or other low impact development (example: rain gardens, bio-retention, porous pavement) to control flow during construction? Yes No List and describe BMPs: None Installation Schedules: [Insert text here] Inspection and Maintenance plan: [Insert text here] Responsible Staff: [Insert text here] Element 4: Install Sediment Controls (2.1.4) Describe how you will minimize sediment discharges from the site. Construct sediment control BMPs as one of the first steps of grading. These BMPs must be functional before other land disturbing activities â€“ especially grading and filling â€“ take place. Describe the BMPs identified to filter sediment prior to it being discharged to an infiltration system or leaving the construction site. Describe how you will direct stormwater for maximum infiltration where feasible. Describe how you will not interfere with the movement of juvenile Salmonids attempting to enter off-channel areas or drainages. Describe how you will respond if sediment controls are ineffective and turbid water is observed discharging from the site. Consider the amount, frequency, intensity and duration of precipitation, soil characteristics, and site characteristics when selecting sediment control BMPs. List and describe BMPs: BMP C233-Silt Fence Installation Schedules: Installed at start of construction Inspection and Maintenance plan: Inspect weekly or after rainfall event Responsible Staff: CESCL Element 5: Stabilize Soils (2.1.5) Describe how you will stabilize exposed and unworked soils throughout the life of the project (i.e. temporary and permanent seeding, mulching, erosion control fabrics, etc.). Describe how you will stabilize soil stockpiles. Describe how you will minimize the amount of soil exposed throughout the life of the project. Describe how you will minimize the disturbance of steep slopes. Describe how you will minimize soil compaction. Describe how you will stabilize contaminated soil and contaminated soil stockpiles if applicable. Exposed and unworked soils will be stabilized according to the time period set forth for dry and wet seasons, on the west or east sides of the crest of the Cascade Mountains. Select your regionâ€™s table and delete the others. West of the Cascade Mountains Crest Number of Days Soils Can be Season Dates Left Exposed During the Dry Season May 1 â€“ September 30 7 days During the Wet Season October 1 â€“ April 30 2 days East of the Cascade Mountains Crest, except the Central Basin* Number of Days Soils Can be Season Dates Left Exposed During the Dry Season July 1 â€“ September 30 10 days During the Wet Season October 1 â€“ June 30 5 days The Central Basin*, East of the Cascade Mountain Crest Number of Days Soils Can be Season Dates Left Exposed During the Dry Season July 1 â€“ September 30 30 days During the Wet Season October 1 â€“ June 30 15 days *Note: The Central Basin is defined as the portions of Eastern Washington with mean annual precipitation of less than 12 inches. Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on the weather forecast. Anticipated project dates: Start date: March 2020 End date: Aug 2020 Will you construct during the wet season? Yes No List and describe BMPs: BMP C140-Dust Control Installation Schedules: Dust control will be used from beginning of construction to final stabiliazation of soi. Inspection and Maintenance plan: Inspect weekly Responsible Staff: CESCL Element 6: Protect Slopes (2.1.6) West of the Cascade Mountains Crest Describe how slopes will be designed, constructed, and protected to minimize erosion. Temporary pipe slope drains must handle the peak 10-minute flow rate from a Type 1A, 10- year, 24-hour frequency storm for the developed condition. Alternatively, the 10-year, 1-hour flow rate predicted by an approved continuous runoff model, increased by a factor of 1.6, may be used. The hydrologic analysis must use the existing land cover condition for predicting flow rates from tributary areas outside the project limits. For tributary areas on the project site, the analysis must use the temporary or permanent project land cover condition, whichever will produce the highest flow rates. If using the Western Washington Hydrology Model (WWHM) to predict flows, bare soil areas should be modeled as â€œlandscaped areaâ€. Describe how you will reduce scouring within constructed channels that are cut down a slope. East of the Cascade Mountain Crest Describe how slopes will be designed, constructed, and protected to minimize erosion. Temporary pipe slope drains must handle the expected peak flow velocity from a 6-month, 3- hour storm for the developed condition, referred to as the short duration storm. Describe how you will reduce scouring within constructed channels that are cut down a slope. Will steep slopes be present at the site during construction? Yes No List and describe BMPs: None Installation Schedules: Inspection and Maintenance plan: Responsible Staff: Element 7: Protect Drain Inlets (2.1.7) Describe how you will protect all operable storm drain inlets so that stormwater runoff does not enter the stormwater conveyance system. Describe how you will remove sediment that enters the stormwater conveyance system (i.e. filtration, treatment, etc.). Keep in mind inlet protection may function well for coarse sediment but is less effective in filtering finer particles and dissolved constituents. Inlet protection is the last component of a treatment train and protection of drain inlets include additional sediment and erosion control measures. Inlet protection devices will be cleaned (or removed and replaced), when sediment has filled the device by one third (1/3) or as specified by the manufacturer. Inlets will be inspected weekly at a minimum and daily during storm events. List and describe BMPs: BMP C220-Storm Drain Inlet Protection Installation Schedules: Installed prior to construction Inspection and Maintenance plan: Inspected weekly or after rain event Responsible Staff: CESCL Element 8: Stabilize Channels and Outlets (2.1.8) Describe how you will prevent downstream erosion where site runoff is to be conveyed in channels, discharged to a stream or, discharged to a natural drainage point. West of the Cascade Mountains Crest On-site conveyance channels must handle the peak 10-minute flow rate from a Type 1A, 10- year, 24-hour frequency storm for the developed condition. Alternatively, the 10-year, 1-hour flow rate predicted by an approved continuous runoff model, increased by a factor of 1.6, may be used. The hydrologic analysis must use the existing land cover condition for predicting flow rates from tributary areas outside the project limits. For tributary areas on the project site, the analysis must use the temporary or permanent project land cover condition, whichever will produce the highest flow rates. If using the WWHM to predict flows, bare soil areas should be modeled as â€œlandscaped areaâ€. Provide stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes, and downstream reaches, will be installed at the outlets of all conveyance systems. List and describe BMPs: None Installation Schedules: NA Inspection and Maintenance plan: NA Responsible Staff: NA Element 9: Control Pollutants (2.1.9) The following pollutants are anticipated to be present on-site: Table 2 â€“ Pollutants Pollutant (and source, if applicable) Concrete Describe how you will handle and dispose of all pollutants, including waste materials and demolition debris, in a manner that does not cause contamination of stormwater. Describe how you will cover, contain, and protect from vandalism all chemicals, liquid products, petroleum products, and other polluting materials. Describe how you will manage known contaminants to prevent their discharge with stormwater to waters of the State (i.e. treatment system, off-site disposal). Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on-site? Yes No Provisions of spill prevention plan will be used If yes, describe spill prevention and control measures in place while conducting maintenance, fueling, and repair of heavy equipment and vehicles. If yes, also provide the total volume of fuel on-site and capacity of the secondary containment for each fuel tank. Secondary containment structures shall be impervious. Will wheel wash or tire bath system BMPs be used during construction? Yes No If yes, provide disposal methods for wastewater generated by BMPs. If discharging to the sanitary sewer, include the approval letter from your local sewer district under Correspondence in Appendix C. Will pH-modifying sources be present on-site? Yes No If yes, check the source(s). Table 3 â€“ pH-Modifying Sources None X Bulk cement Cement kiln dust Fly ash Other cementitious materials X New concrete washing or curing waters Waste streams generated from concrete grinding and sawing Exposed aggregate processes Dewatering concrete vaults X Concrete pumping and mixer washout waters Recycled concrete Other (i.e. calcium lignosulfate) [please describe] Describe BMPs you will use to prevent pH-modifying sources from contaminating stormwater. List and describe BMPs: BMP C151-Concrete Handling, BMP C152-Sawcutting, BMP C154-Concrete Washout Installation Schedules: Installed prior to concrete work being performed Inspection and Maintenance plan: Inspected weekly Responsible Staff: CESCL Adjust pH of stormwater if outside the range of 6.5 to 8.5 su. Obtain written approval from Ecology before using chemical treatment with the exception of CO2 or dry ice to modify pH. Concrete trucks must not be washed out onto the ground, or into storm drains, open ditches, streets, or streams. Excess concrete must not be dumped on-site, except in designated concrete washout areas with appropriate BMPs installed. Element 10: Control Dewatering (2.1.10) Describe where dewatering will occur, including source of the water to be removed. State clearly if dewatering water is contaminated or has the potential to be contaminated. Water from foundations, vaults, and trenches with characteristics similar to stormwater runoff shall be discharged into a controlled conveyance system before discharging to a sediment trap or sediment pond. Clean dewatering water will not be routed through stormwater sediment ponds. Only clean, non-turbid dewatering water (such as well-point groundwater) may be discharged to systems tributary to, or directly into, surface waters of the State, provided the dewatering flow does not cause erosion or flooding of receiving waters. Describe how you will manage dewatering water to prevent the discharge of contaminants to waters of the State, including dewatering water that has comingled with stormwater (i.e. treatment system, off-site disposal). Dewatering is anticipated for installation of side sewer connection. Water will be pumped out with a trash pump and dispersed onsite. No contamination is anticipated. Check treatment of disposal option for dewatering water, if applicable: Table 4 â€“ Dewatering BMPs Infiltration Transport off-site in a vehicle (vacuum truck for legal disposal) Ecology-approved on-site chemical treatment or other suitable treatment technologies Sanitary or combined sewer discharge with local sewer district approval (last resort) Use of sedimentation bag with discharge to ditch or swale (small volumes of localized dewatering) List and describe BMPs: NA Installation Schedules: NA Inspection and Maintenance plan: NA Responsible Staff: NA Element 11: Maintain BMPs (2.1.11) This section is a list of permit requirements and does not have to be filled out. All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained and repaired as needed to ensure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP specification (see Volume II of the SWMMWW or Chapter 7 of the SWMMEW). Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to once every calendar month. All temporary ESC BMPs shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be stabilized on-site or removed. Disturbed soil resulting from removal of either BMPs or vegetation shall be permanently stabilized. Additionally, protection must be provided for all BMPs installed for the permanent control of stormwater from sediment and compaction. BMPs that are to remain in place following completion of construction shall be examined and restored to full operating condition. If sediment enters these BMPs during construction, the sediment shall be removed and the facility shall be returned to conditions specified in the construction documents. Element 12: Manage the Project (2.1.12) The project will be managed based on the following principles: Â· Projects will be phased to the maximum extent practicable and seasonal work limitations will be taken into account. Â· Inspection and monitoring: o Inspection, maintenance and repair of all BMPs will occur as needed to ensure performance of their intended function. o Site inspections and monitoring will be conducted in accordance with Special Condition S4 of the CSWGP. Sampling locations are indicated on the Site Map. Sampling station(s) are located in accordance with applicable requirements of the CSWGP. Â· Maintain an updated SWPPP. o The SWPPP will be updated, maintained, and implemented in accordance with Special Conditions S3, S4, and S9 of the CSWGP. As site work progresses the SWPPP will be modified routinely to reflect changing site conditions. The SWPPP will be reviewed monthly to ensure the content is current. Check all the management BMPs that apply at your site: Table 5 â€“ Management X Design the project to fit the existing topography, soils, and drainage patterns X Emphasize erosion control rather than sediment control X Minimize the extent and duration of the area exposed X Keep runoff velocities low X Retain sediment on-site X Thoroughly monitor site and maintain all ESC measures X Schedule major earthwork during the dry season Other (please describe) Optional: Fill out Table 6 by listing the BMP associated with specific construction activities. Identify the phase of the project (if applicable). To increase awareness of seasonal requirements, indicate if the activity falls within the wet or dry season. Table 6 â€“ BMP Implementation Schedule Phase of Construction Wet/Dry Stormwater BMPs Date Project Season [Insert construction [Insert BMP] [MM/DD/YYYY] [Insert activity] Season] Phase of Construction Wet/Dry Stormwater BMPs Date Project Season [Insert construction [Insert BMP] [MM/DD/YYYY] [Insert activity] Season] Element 13: Protect Low Impact Development (LID) BMPs (2.1.13) Describe LIDs. Permittees must protect all Bioretention and Rain Garden facilities from sedimentation through installation and maintenance of erosion and sediment control BMPs on portions of the site that drain into the Bioretention and/or Rain Garden facilities. Restore the facilities to their fully functioning condition if they accumulate sediment during construction. Restoring the facility must include removal of sediment and any sediment-laden Bioretention/Rain Garden soils, and replacing the removed soils with soils meeting the design specification. Permittees must maintain the infiltration capabilities of Bioretention and Rain Garden facilities by protecting against compaction by construction equipment and foot traffic. Protect completed lawn and landscaped areas from compaction due to construction equipment. Permittees must control erosion and avoid introducing sediment from surrounding land uses onto permeable pavements. Do not allow muddy construction equipment on the base material or pavement. Do not allow sediment-laden runoff onto permeable pavements. Permittees must clean permeable pavements fouled with sediments or no longer passing an initial infiltration test using local stormwater manual methodology or the manufacturerâ€™s procedures. Permittees must keep all heavy equipment off existing soils under LID facilities that have been excavated to final grade to retain the infiltration rate of the soils. Describe how you will protect LID facilities from sedimentation, protect soils from compaction, and maintain the infiltration capabilities. Describe how you will clean permeable pavements fouled with sediments. N/A as there are no biofiltration facilities onsite. Pollution Prevention Team (3.0) Table 7 â€“ Team Information Title Name(s) Phone Number Certified Erosion and Steve Rushton - Coast 425-315-4799 Sediment Control Lead (CESCL) Resident Engineer TBD Emergency Ecology Contact TBD 425-649-7000 Emergency Permittee/ Owner Tim Shoultz-SmartCAP 425-896-8561 Contact Non-Emergency Owner Same Contact Monitoring Personnel Ecology Regional Office [Insert Regional Office] [Insert General Number] Monitoring and Sampling Requirements (4.0) Monitoring includes visual inspection, sampling for water quality parameters of concern, and documentation of the inspection and sampling findings in a site log book. A site log book will be maintained for all on-site construction activities and will include: Â· A record of the implementation of the SWPPP and other permit requirements Â· Site inspections Â· Stormwater sampling data Create your own Site Inspection Form or use the Construction Stormwater Site Inspection Form found on Ecologyâ€™s website. https://www.ecology.wa.gov/Regulations-Permits/Permits- certifications/Stormwater-general-permits/Construction-stormwater-permit File a blank form under Appendix D. The site log book must be maintained on-site within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See CSWGP Special Condition S8 and Section 5 of this template. Complete the following paragraph for sites that discharge to impaired waterbodies for fine sediment, turbidity, phosphorus, or pH: The receiving waterbody, insert waterbody name, is impaired for: insert impairment. All stormwater and dewatering discharges from the site are subject to an effluent limit of 8.5 su for pH and/or 25 NTU for turbidity. Site Inspection (4.1) Site inspections will be conducted at least once every calendar week and within 24 hours following any discharge from the site. For sites that are temporarily stabilized and inactive, the required frequency is reduced to once per calendar month. The discharge point(s) are indicated on the Site Map (see Appendix A) and in accordance with the applicable requirements of the CSWGP. Stormwater Quality Sampling (4.2) Turbidity Sampling (4.2.1) Requirements include calibrated turbidity meter or transparency tube to sample site discharges for compliance with the CSWGP. Sampling will be conducted at all discharge points at least once per calendar week. Method for sampling turbidity: Check the analysis method you will use: Table 8 â€“ Turbidity Sampling Method Turbidity Meter/Turbidimeter (required for disturbances 5 acres or greater in size) Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size) The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency less than 33 centimeters. If the dischargeâ€™s turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to or greater than 6 cm, the following steps will be conducted: 1. Review the SWPPP for compliance with Special Condition S9. Make appropriate revisions within 7 days of the date the discharge exceeded the benchmark. 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. 3. Document BMP implementation and maintenance in the site log book. If the turbidity exceeds 250 NTU or the transparency is 6 cm or less at any time, the following steps will be conducted: 1. Telephone or submit an electronic report to the applicable Ecology Regionâ€™s Environmental Report Tracking System (ERTS) within 24 hours. https://www.ecology.wa.gov/About-us/Get-involved/Report-an-environmental-issue Â· Central Region (Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, Yakima): (509) 575-2490 Â· Eastern Region (Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman): (509) 329-3400 Â· Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish, Whatcom): (425) 649-7000 Â· Southwest Region (Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, Wahkiakum,): (360) 407-6300 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period 3. Document BMP implementation and maintenance in the site log book. 4. Continue to sample discharges daily until one of the following is true: Â· Turbidity is 25 NTU (or lower). Â· Transparency is 33 cm (or greater). Â· Compliance with the water quality limit for turbidity is achieved. o1 - 5 NTU over background turbidity, if background is less than 50 NTU o1% - 10% over background turbidity, if background is 50 NTU or greater Â· The discharge stops or is eliminated. pH Sampling (4.2.2) pH monitoring is required for â€œSignificant concrete workâ€ (i.e. greater than 1000 cubic yards poured concrete or recycled concrete over the life of the project).The use of engineered soils (soil amendments including but not limited to Portland cement-treated base [CTB], cement kiln dust [CKD] or fly ash) also requires pH monitoring. For significant concrete work, pH sampling will start the first day concrete is poured and continue until it is cured, typically three (3) weeks after the last pour. For engineered soils and recycled concrete, pH sampling begins when engineered soils or recycled concrete are first exposed to precipitation and continues until the area is fully stabilized. If the measured pH is 8.5 or greater, the following measures will be taken: 1. Prevent high pH water from entering storm sewer systems or surface water. 2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate technology such as carbon dioxide (CO2) sparging (liquid or dry ice). 3. Written approval will be obtained from Ecology prior to the use of chemical treatment other than CO2 sparging or dry ice. Method for sampling pH: Check the analysis method you will use: Table 8 â€“ pH Sampling Method pH meter pH test kit Wide range pH indicator paper Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies (5.0) 303(d) Listed Waterbodies (5.1) The 303(d) status is listed on the Water Quality Atlas: https://ecology.wa.gov/Water- Shorelines/Water-quality/Water-improvement/Assessment-of-state-waters-303d Circle the applicable answer, if necessary: Is the receiving water 303(d) (Category 5) listed for turbidity, fine sediment, phosphorus, or pH? Yes No List the impairment(s): [Insert text here] The receiving waterbody, insert waterbody name, is impaired for: insert impairment. All stormwater and dewatering discharges from the site are subject to an effluent limit of 8.5 su for pH and/or 25 NTU for turbidity. If yes, discharges must comply with applicable effluent limitations in S8.C and S8.D of the CSWGP. Describe the method(s) for 303(d) compliance: List and describe BMPs: [Insert text here] TMDL Waterbodies (5.2) Waste Load Allocation for CWSGP discharges: [Insert text here] Describe themethod(s) for TMDL compliance: List and describe BMPs: [Insert text here] Discharges to TMDL receiving waterbodies will meet in-stream water quality criteria at the point of discharge. The Construction Stormwater General Permit Proposed New Discharge to an Impaired Water Body form is included in Appendix F. Reporting and Record Keeping (6.0) Record Keeping (6.1) This section does not need to be filled out. It is a list of reminders for the permittee. Site Log Book (6.1.1) A site log book will be maintained for all on-site construction activities and will include: Â· A record of the implementation of the SWPPP and other permit requirements Â· Site inspections Â· Sample logs Records Retention (6.1.2) Records will be retained during the life of the project and for a minimum of three (3) years following the termination of permit coverage in accordance with Special Condition S5.C of the CSWGP. Permit documentation to be retained on-site: Â· CSWGP Â· Permit Coverage Letter Â· SWPPP Â· Site Log Book Permit documentation will be provided within 14 days of receipt of a written request from Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with Special Condition S5.G.2.b of the CSWGP. Updating the SWPPP (6.1.3) The SWPPP will be modified if: Â· Found ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. Â· There is a change in design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the State. The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine additional or modified BMPs are necessary for compliance. An updated timeline for BMP implementation will be prepared. Reporting (6.2) Discharge Monitoring Reports (6.2.1) Select and retain applicable paragraph. Cumulative soil disturbance is less than one (1) acre; therefore, Discharge Monitoring Reports (DMRs) will not be submitted to Ecology because water quality sampling is not being conducted at the site. Or Cumulative soil disturbance is one (1) acre or larger; therefore, Discharge Monitoring Reports (DMRs) will be submitted to Ecology monthly. If there was no discharge during a given monitoring period the DMR will be submitted as required, reporting â€œNo Dischargeâ€. The DMR due date is fifteen (15) days following the end of each calendar month. DMRs will be reported online through Ecologyâ€™s WQWebDMR System. To sign up for WQWebDMR go to: https://www.ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Water-quality- permits-guidance/WQWebPortal-guidance Notification of Noncompliance (6.2.2) If any of the terms and conditions of the permit is not met, and the resulting noncompliance may cause a threat to human health or the environment, the following actions will be taken: 1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable Regional office ERTS phone number (Regional office numbers listed below). 2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or correct the noncompliance. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Specific information to be included in the noncompliance report is found in Special Condition S5.F.3 of the CSWGP. Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6 cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as required by Special Condition S5.A of the CSWGP. Â· Central Region at (509) 575-2490 for Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, or Yakima County Â· Eastern Region at (509) 329-3400 for Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, or Whitman County Â· Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit, Snohomish, or Whatcom County Â· Southwest Region at (360) 407-6300 for Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, or Wahkiakum Include the following information: 1. Your name and / Phone number 2. Permit number 3. City / County of project 4. Sample results 5. Date / Time of call 6. Date / Time of sample 7. Project name In accordance with Special Condition S4.D.5.b of the CSWGP, the Ecology Regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water. Appendix/Glossary A. Site Map The site map must meet the requirements of Special Condition S9.E of the CSWGP B. BMP Detail Insert BMPs specification sheets here. Download BMPs from the Ecology Construction Stormwater website at: https://www.ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Stormwater- permittee-guidance-resources/Stormwater-manuals C. Correspondence Ecology EPA Local Government D. Site Inspection Form Create your own or download Ecologyâ€™s template: https://www.ecology.wa.gov/Regulations- Permits/Permits-certifications/Stormwater-general-permits/Construction-stormwater-permit E. Construction Stormwater General Permit (CSWGP) Download CSWGP: https://www.ecology.wa.gov/Regulations-Permits/Permits- certifications/Stormwater-general-permits/Construction-stormwater-permit F. 303(d) List Waterbodies / TMDL Waterbodies Information Proposed New Discharge to an Impaired Water Body form SWPPP Addendum addressing impairment G. Contaminated Site Information Administrative Order Sanitary Discharge Permit Soil Management Plan Soil and Groundwater Reports Maps and Figures Depicting Contamination H. Engineering Calculations TerraVista NW,LLC Appendix B Geotechnical Report November 15, 2019 Eric Scott, P.E., Principal TerraVista NW, LLC 3204 Smokey Point Drive, Suite 207 Arlington, WA 98223 Subject: Infiltration Feasibility & Mounding Assessment Proposed Commercial Site Improvements â€“ Trailer Boss 16523 Smokey Point Blvd, Arlington, Washington MTC Project No.: 19B335 Dear Mr. Scott: At your request, Materials Testing & Consulting, Inc. (MTC) has completed a targeted site characterization for infiltration assessment at the above referenced site proposed for stormwater improvements along with the planned site development. MTC understands the client intends to develop the project site with a new 36x44-foot office, a 40x54-foot shop, and pave the majority of the interior of the site to provide parking areas and trailer storage. The project will install decentralized stormwater improvements to accompany the expanded site use. The client and design engineer have requested this infiltration study be performed in support of stormwater facility planning and final design. In addition, the designer has asked for calculation of groundwater mounding using simplified methods to determine minimum vertical separation guidelines for the facilities from shallow seasonal high groundwater. Preliminary discussions indicate stormwater infiltration will be done by multiple linear infiltration trenches or buried cells at locations to be determined spread throughout the site interior, if feasible conditions allow. Design of these features is pending confirmation of site suitability for infiltration and determination of design rates and minimum separation requirements by this study. MTC has performed this infiltration assessment in accordance with site characterization guidelines presented in the Washington Department of Ecology Stormwater Management Manual for Western Washington, 2012/2014 edition (SMMWW, 2012/2014) as adopted by the City of Arlington. A summary of MTCâ€™s field findings, laboratory results, interpretations, and recommendations pertaining to the proposed infiltration facilities including long-term design rates are provided herein. In addition, the results of Cation Exchange Capacity (CEC) and Organic Content (OC) analyses conducted on representative soil samples from the potential infiltration areas are attached at the end of this report for consideration in stormwater treatment if required. Environmental â— Geotechnical Engineering â— Special Inspecon â— Non-Destructive Testing â— Materials Tesng Burlington|Olympia|Bellingham|Silverdale|Tukwila 360.755.1990 www.mtc-inc.net Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Site Exploration and Assessment Methodology: On October 16, 2019, an MTC Project Geologist visited the site to observe and direct excavation of test pits for infiltration assessment and to collect soil samples for laboratory gradation analysis. MTC personnel observed excavation of test pits at six locations as determined on site by an MTC Geologist based on the proposed project layout, and space accessible for work at the time of the visit. The project site contains an existing business in a rectangular area (northwest portion) and will expand into a second rectangular area (southeast) oriented perpendicular to the first, with a small central area connecting them (see map). The northwestern portion of the site was generally inaccessible due to trailer staging and prevalent utilities, however MTC was provided a previous soils report from the site that included explorations in this area indicating similar conditions throughout the site. Test Pits TP-1 through TP-4 were excavated in the undeveloped southeastern part of the site. Locations were in the south-central, southeast, northeast, and northwest areas of the southeast lot, respectively. TP- 5 was sited in the south-central connecting area between the two lots. TP-6 was located in the south- central portion of the northwestern in-use lot. The previous soils report included two test pits in each of the two lots. An abandoned â€˜wet wellâ€™ was also observed on site just west of TP-6 where there had been a historically demolished residence. Explorations were field located by MTC and arranged for optimum coverage of potential areas for infiltration design. Backhoe test pits were completed to termination depths ranging from approximately 5.3 to 7.7 feet below present grade (BPG). Explorations were terminated upon sidewall caving due to groundwater inundation. Explorations were monitored by MTC personnel, who examined and classified the materials encountered in accordance with the Unified Soil Classification System (USCS) and ASTM D2487, obtained representative soil samples, and recorded pertinent information including soil stratigraphy, soil engineering characteristics, and indications of groundwater occurrences as well as visual evidence of seasonal groundwater. Upon completion, test pits were backfilled with soil tailings. Grab soil samples were collected from representative soil horizons during test pit excavation and at potential infiltration depths, as depicted on the attached logs. All samples were placed in plastic bags to limit moisture loss, labeled, and returned to MTCâ€™s laboratory for analysis and storage. Samples will be retained for a minimum of 90 days from the date of collection. A location and vicinity map are provided in Figure 1, Appendix A1. A site plan with approximate test locations is provided in Figure 2, Appendix A2. Attached in Appendix B are photos of the site and explorations in progress. Exploration logs are presented in Appendix C, with a USCS classification chart provided as Figure 3. Results of laboratory analyses on soil samples collected during the field visit are attached in Appendix D. 2 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Site Conditions: The project site is located in Arlington, Washington, east of the I-5 corridor on the east side of Smokey Point Boulevard, and roughly Â¼-mile south of SR 531. The property is located within a generally commercialized area, though it is neighbored to the south by a remaining single-family residence with a small yard. The west and north property boundaries are made up of Smokey Point Blvd and 166th Place NE, respectively. A moderately-sized power substation is located directly to the east and north, against the northwest and southeast areas respectively, and to the east of that is a preschool complex. The large site to the east of the southeast parcel is partially undeveloped. The site interior is approximately flat and is divided into two parcels in differing stages of development. Both areas have been cleared of all major vegetation. The northwest & central area contains chipped gravel throughout and is currently in use as a parking and staging area for Trailer Boss merchandise. Other minor structures observed in the northwest area include a small concrete parking pad to the northeast, a temporary office trailer to the east, an abandoned residential â€˜wet wellâ€™ in the southwest, and temporary lighting throughout the interior. The southeast area is generally undeveloped, though it has been graded, which apparently removed topsoil and the majority of organic material in preparation for the proposed development. Subsurface Soil Conditions: Subsurface soils were observed and catalogued during test pit excavations. This section summarizes our general understanding of site soil conditions gained from completing field explorations and laboratory analyses. We also reviewed prior report information provided by the client, as discussed below. The site exhibited various surface conditions including gravel over reworked native fill in the northwest area, and native alluvium exposed after topsoil stripping in the southeast. No topsoil was observed, though some organic material was seen in TP-5 and TP-6 within reworked fill materials. No obvious fill was observed in the southeastern area, indicating that grading to date has only included material removal. The upper undisturbed native soil profile beginning at the surface or by 1.25 to 1.5 feet BPG was composed of sand with silt to silty sand. Fines content within the upper unit was visually estimated to range from 10 to 15% and locally up to about 30%. Soils at TP-4 through TP-6 exhibited some local cohesion and blocky habit in the upper 1.5 to 3.0 feet, which correlated to a relatively higher fines content. A similar horizon, approximately 6 inches thick was observed at around 5.5 feet only in TP-6. Below the upper deposits, underlying material generally consisted of sand to sand with gravel & coarsening downward. The lower unit had minor to trace fines, and was moist to wet with depth. The upper boundary varied between test pits, though was generally at around 3 to 4 feet BPG. The outliers were at TP-1, where it was encountered at 2.2 feet, and at TP-6 where it was reached at 3.5 feet BPG. 3 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Previous work by others (Geotech Consultants, Inc.; 2016) was reviewed for general coverage and understanding of the full site conditions. The GCI report describes finding similar conditions of an upper silty sand and lower sand at all of four test pits. The interface between the units was also variable by location. Clean sand was contacted typically between 3 to 4 feet BPG, with soils above coarsening with depth. TP-1 was done in an area inaccessible during our field work, at the north-central part of the west lot. Their logging of silty sand to sand with silt to about 3.5 feet BPG corresponds closely with the closest MTC test pit (TP-6) further to the south. By comparison with the GCI results, we anticipate conditions to be widely similar throughout the site. Geologic Literature: The Geologic Map of the Arlington West 7.5 minute quadrangle, published by the US Geologic Survey depicts the site as within an area of Quaternary Recessional Outwash (Marysville Sand Member-Qvrm) based on 1:24,000-scale mapping. Qvrm deposits are associated with the meltwaters of the receding Vashon glacier. These deposits are typically described as stratified or massive, clean outwash sand with local areas of fine gravel, silt, and clay. In our experience, the uppermost deposits and cover soils of this unit are commonly composed of silty sand grading to coarse sand with depth. Shallow subsurface conditions at the site are mapped by the USDA NRCS Web Soil Survey as Custer Fine Sandy Loam (#13). Custer Fine Sandy Loam is described as deposited on outwash plains from a parent material of glacial outwash. Typical profile includes fine sandy loam to 9 inches, underlain by sand to past 60 inches. Where undrained, the soil is listed as poorly drained with a moderately high capacity to transmit water through its most limiting layer (upper conditions). Depth to the seasonal high- water table is listed at 0 to 12 inches. It is a member of Hydrologic Soil Group C/D. Native soil conditions encountered in the field (below surface fills, if present) are interpreted to consist of outwash sand deposits, ranging commonly from silty sand to sand with silt at upper levels with predominantly coarse-grained units beginning on average around 4 feet depth. Soils observed in field explorations generally correspond with mapped geology. Soils also broadly correspond with soil survey data, although the groundwater conditions documented by MTC and previous work differ from the described â€œundrainedâ€ conditions per the NRCS. Surface and Subsurface Water Conditions: The project site is roughly 0.4 miles northeast of Gissberg Twin Lakes, and roughly the same distance from small tributaries of Quilceda Creek to the south and east. The site is also approximately 3.2 miles south of the Stillaguamish River. No other major surface water features are present in the project area. 4 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 A prevalent groundwater table was encountered at the time of our field investigation in the fall season. All explorations also contained free water seepage at similar depths to the water table. After some open time for stabilization, groundwater was measured at around 5 feet depth in TP-1 and TP-2. Water levels were recorded between 6 to 7 feet depth in Test Pits TP-3 through TP-6 and within the nearby â€˜wet wellâ€™. Groundwater was most shallow in the southeast part of the site compared to surface grade, and relatively deeper to the west. This appears to be at least partly a function of relative surface grades between the two areas. Given the timeframe of the explorations in the early fall season following moderately high levels of precipitation (as well as precipitation during field work), conditions are expected to be seasonally elevated from base dry season levels, though not at fully developed wet season groundwater levels. Peak seasonal groundwater levels are normally established by mid-winter and persist through early spring. We observed for soil mottling and oxidation staining patterns to estimate seasonal high groundwater levels anticipated for the winter season. Shallow scattered mottling observed in the upper unit and along the top portion of the underlying sand is interpreted to be due to downward transmission of meteoric surface waters, and not a result of full seasonal saturation. Scattered mottling was observed throughout the upper deposits at all locations explored. No heavy linear feature, such as heavy oxidation banding, was seen that would strongly suggest a seasonal high water level. The absence of such evidence is not uncommon in predominantly coarse-grained soils. We did note the onset of low-chroma coloration within the lower sand unit before end depths suggesting groundwater inundation above the elevations observed. GCIâ€™s explorations were performed in late March of 2016, a year of notably higher rainfall. Their findings most likely reflect a stabilized high wet season level (not necessarily true peak but at least sustained). GCI recorded static groundwater levels of 3 to 5 feet BPG. Similar to our observations, the groundwater level was higher relative to surface grade at the southeast lot (4.0 and 3.0 feet BPG), and marginally deeper at the northwest lot (4.0 and 5.0 feet BPG). While MTC cannot certify the accuracy of the work by others, the recorded levels appear to correspond well with our observations of soil coloration. MTCâ€™s current scope of investigation did not include direct observation and determination of seasonal groundwater variations, or conclusive measurement of groundwater elevations by establishment of monitoring wells. The conditions on field logs are valid only for the date of exploration. Estimated seasonal high groundwater conditions based on indirect mottling evidence shall be understood as interpreted rather than a statement of fact. At the request of the client, MTC can perform additional site characterization involving the monitoring of seasonal groundwater elevations if required for final design and approval. 5 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Infiltration Assessment & Commentary: Gradation Analysis Method & Results During test pit excavations, MTC collected representative samples of soils among native strata at and below potential infiltration depths. No target depths or locations were set prior to field work. Based on project discussions, test pit observations, and the GCI work, we assume infiltration depths will be shallow and via linear infiltration trenches. MTC understands that the final locations, sizes, and depths of the infiltration facilities will be refined following the results of this study. Laboratory gradation analyses were completed via sieve tests for general rate determination to supplement field observations. Results of laboratory testing are summarized below. Laboratory results were interpreted to hydraulic conductivity (Ksat) values in accordance with methods of the Washington State Department of Ecology Stormwater Management Manual for Western Washington (SMMWW), 2012/2014. Standard correction factors were applied as noted in the reference documents. Data and Ksat values are summarized in Table 1. Gradation results were applied to the Massmann (2003) equation (1) to calculate Ksat representing the initial saturated hydraulic conductivity, as described in the 2012 DOE SMMWW Volume III 3.3.6.3. (1) log10(Ksat) = -1.57 + 1.90*D10 + 0.015*D60 - 0.013*D90 - 2.08*ff Table 2 reports for each sample the input laboratory values and calculated Ksat. Corrected Ksat values presented below are a product of the initial Ksat and correction factor CFT. For a generalized design situation, we have applied an average site variability factor of CFv = 0.5 along with typical values of CFt = 0.4 (for the Grain Size Method) and CFm = 0.9 (assuming standard influent control). (2) CFT = CFv x CFt x CFm = 0.5 x 0.4 x 0.9 = 0.18 Table 1. Results of Massmann Analysis Depth Ff Ksat Corrected Ksat TP # USCS D10 D60 D90 (BPG) (%) (inches/hour) (inches/hour) 2 2 SP-SM 0.12 0.578 1.785 6.9 44.81 8.07 2 5.5 SP 0.172 0.719 1.93 1.7 72.21 13.00 4 3 SP-SM 0.092 0.299 0.408 7.3 40.14 7.23 5 4 SP 0.152 0.358 1.372 1.5 67.08 12.07 6 2 SM 0.026 0.211 0.404 28.8 10.71 1.93 6 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Facility Design Discussion and Rates MTC understands the stormwater system will undergo further design pending the results of this assessment to confirm general feasibility of infiltration, design rates, and viable minimum separation to groundwater. Based on discussions with the designer, on-site stormwater management is anticipated to consist of a series of shallow, distributed linear infiltration trenches beneath or at the perimeter of paved areas. Locations and depths are to be determined. Grain size analysis methods based on SMMWW 2012/2014 standard calculation criteria yielded Corrected Ksat values for native alluvial soils in the upper 6 feet of the subsurface profile ranging from about 2 to 13 inches per hour. Rates should be divided into two sections for design purposes based on soil stratigraphy encountered. The upper silty sand to sand with silt (where tested) yielded Ksat values of as low as about 2 inches per hour (where fines content was elevated up to 25% to 30% maximum) and higher values of 7 to 8 inches per hour where fines contents were below 10%. These rates were derived from samples collected at 2 to 3 feet BPG. The sample from 2.0 feet BPG in TP-6 had a fines content approaching 30%, which is interpreted to be representative of the finer-grained end of the spectrum for the shallow unit where observed. For general site-wide application with locations and depths to be determined, we recommend applying a maximum design Ksat value of 2.0 inches/hour. Given the range of shallow conditions observed, actual infiltration rates are expected to be equal or better than this value at a given location. Use of a relatively low rate will also help to minimize potential for groundwater mounding. Rates derived from samples within the lower sand unit at depths of 4.0 and 5.5 feet BPG were in the realm of 12 to 13 inches per hour. While the transmission potential is greater with depth, the limiting factor of seasonal high groundwater may preclude placement of systems at that level. If specific design locations and dimensions are able to maintain minimum vertical separations as discussed below, a Ksat value of up to 10 inches/hour may be used for infiltration into the clean sand unit. For systems placed at greater depths, it is likely that wet season monitoring and explorations at final design locations will be required to closely dial in depths for final design and approval. The derived rates are meant to provide a general characterization of shallow subsurface transmission potential for the designerâ€™s use, but are not necessarily intended to be applied as a final infiltration rate for facilities of an undetermined location and depth or for systems of a larger size/volume than anticipated at this time. The inherent site limitation of depth to seasonal groundwater must be accounted for in design. We recommend the design rate be applied conservatively, and systems should maintain as much vertical separation as possible. The facility designer should also review assumed correction factors per reference literature to ensure applicability with the proposed development, level of anticipated 7 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 controls, and long-term maintenance plan. The designer may make reasonable adjustments to correction factors and resulting design values based on these criteria to ensure design and operational intent is met. The project may be eligible for an increase in design rate if Pilot Infiltration Testing (PIT) methods are conducted at design locations and depths, which are considered generally more reliable as a confirmation of actual field conditions and therefore can be applied less conservatively. The client can also elect to conduct additional sampling and rate analysis at actual facility locations for adjustment of sizing on a per-location basis. It is our opinion that grain size analysis methods should be suitable for general design use of the proposed systems at this site, in accordance with DoE SMMWW 2012/2014 requirements. The native soils are not considered to be compacted by prior development (aside from surface fills anticipated to be removed below facilities) or consolidated by glacial ice, and were observed to be relatively uniform with no significant cementation or local variations, except for those accounted for as discussed above. At request of the client, MTC can provide additional services for completing PITs or location-specific sampling to verify the final stormwater design. Treatment Suitability MTC subcontracted Cation Exchange Coefficient (CEC) and Organic Content (OC) testing of representative samples of the shallow native deposits considered for infiltration facilities. Soil samples yielded CEC values between 2.6 to 4.7 milliequivalents per 100 grams of soil (meq/100g). Organic content testing recorded between 1.6% and 3.4% organic matter by weight. Table 2 below shows the results from the laboratory testing. In our experience with similar soils, these values appear typical for the soil types encountered and their respective fines and organic contents observed. Table 2. Results of Cation Exchange Coefficient and Organic Content Analysis Depth Organic Content CEC TP # USCS (BPG) (% by weight) (meq/100g) 2 2.0 SP-SM 2.0 2.6 4 3.0 SP-SM 1.6 2.2 6 2.0 SM 3.4 4.7 The Department of Ecology 2012/2014 SMMWW, Volume III, Section 3.3.7 addresses minimum requirements for treatment soils under Site Suitability Criteria. According to SSC-6, native soils with CEC values of at least 5 meq/100g and >1% organic content by weight are considered suitable as treatment media without modification. The addition of soil amendments or the import of treatment- specific soil media may be used to achieve a higher CEC and produce a soil more suitable for treatment if required for design where native soils are deficient. In the case of this site, organic contents are above 8 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 target value (1% minimum) within the upper native soils. However, CEC values recorded are consistently in the range of about 2 to 4 meq/100g, below the minimum treatment threshold. CEC and OC tests were not completed on the lower sand unit. Based on our experience, clean sand soils typically do not meet the minimum standards for treatment without amendment. Therefore, if treatment is required as part of this design, soil amendment or treatment media will be necessary to meet treatment standards. Minimum depth for treatment-suitable soils is cited as 18 inches per the DoE SMMWW. If soils are amended or imported treatment media is installed, the LTIR of the facility must be adjusted accordingly by the designer if these modifications will negatively affect the infiltration rate cited above. Mounding Analysis Methods & Results: At request of the designer, MTC has completed a simplified mounding calculation employing the methods of Zomorodi (1991, 2005) for the anticipated stormwater infiltration system. The referenced method is applicable to relatively uniform soil and groundwater conditions, and use of small-scale linear features which have a length many times the width. In that case, the mound can be assessed in two dimensions, with the facility width being the governing factor along with underlying soil transmissivity (saturated Hydraulic Conductivity). The system is undergoing design at this time. Per project discussions, we anticipate the system will consist of decentralized trenches filled with gravel and supplied by a level perforated pipe or similar distribution system to control application over the infiltration area. From past experience, we assume a distribution pipe will be placed with its base at least 4 to 6 inches above the bottom of the gravel fill. In a practical sense, system failure may be considered as the point at which groundwater level meets the base of the pipe and impedes stormwater delivery. However, for the purposes of our analysis MTC considers maximum allowable mounding to be equal to the base of the gravel bed feature. Ksat Determination MTC performed the following mounding calculations using the simplified solutions for recharge strip mounding derived by Zomorodi (1991, 2005). The purpose was to verify minimum design vertical separation needed from seasonal high groundwater conditions for the anticipated style of facilities. Preparing for the calculations requires determining saturated hydraulic conductivities (Ksat) for representative soil conditions. Ksat values were adopted from the current study laboratory testing and gradation method calculations described above: Upper Unit Silty Sand, Sand With Silt (SM, SP-SM) Ksat = 21.4 feet/day Lower Unit Sand, low fines content (SP) Ksat = 134.2 feet/day 9 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Mounding Calculations In a simplified case, mounding potential for infiltrating water above a water table or restrictive horizon (h) is a function of recharge rate (i), horizontal Ksat (k), and recharge facility width (w) per equation (3): (3) h = (0.86 * i * w) / (k â€“ i) To address a maximum input scenario, the recharge rate (i) was set equal to the design infiltration rate per soil type (recommended values above). Conductivity (k) was applied using representative Ksat values listed above. Width of the facility was varied to determine a balance between practical vertical separation and likely optimal width for the anticipated system style. Mounding inputs and final results are tabulated in Table 3: TABLE 3. Summary of Mounding Analysis Results Hydraulic Soil Recharge Gravel Bed Maximum Mound Mound Height Conductivity Condition (i) Width (w) Central Height (Hc) at Edge (He) (Ksat = k) SM 21.4 4.0 5 0.99 0.64 SP 134.2 20.0 5 0.75 0.47 NOTE: All dimensions in feet. All rates in feet/day. Discussion of Results According to the results of this analysis, mounding will occur to some extent under the facility while stormwater infiltrates vertically and spreads laterally. In our experience with similar trench systems and shallow groundwater, a minimum separation of 1.0 feet can be viable if site soil conditions allow. In this case, the site conditions are generally well suited for infiltration. An optimum maximum width of 5.0 feet for trench features is recommended to minimize mounding potential to about 1 foot or less below the center of the trench. The mound also dissipates laterally from the center of the facility, with heights at the edges of the bed being reduced by over one-third. By about 10 feet from the facility center line, mounding effects on latent groundwater level are negligible. We also note, as discussed above, that shallow soils will typically be more transmissive than the most conservative value used for Ksat determination and mounding calculations. Therefore, actual mounding is anticipated to be less on average than what is noted in Table 3. By using the other Ksat values gained from shallow soil laboratory analysis and assuming a 5-foot trench width, we tabulate a lower mound height of about 0.3 feet. 10 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Closing Remarks: MTC recommends that we be contacted to review proposed stormwater facility design, site preparation plans, and project specifications, to ensure they are consistent with the intent of the recommendations provided herein. In addition, MTC recommends that we be contacted for construction phase testing, observation, and engineering consultation services as may be needed. Such services may include but are not limited to earthwork support consulting, subgrade bearing and infiltration verifications, laboratory materials analysis, and special inspections if required. Mr. Scott, we trust this report presents the information you require. If you have questions, please do not hesitate to call. Respectfully Submitted; 11-15-2019 John R. Gillaspy, L.E.G. Mike Furman, G.I.T. NW Region Geotechnical Division Manager Project Geologist Attached: Limitations and Use of this Report Appendix A1. Location and Vicinity Map Appendix A2. Site Plan with Test Locations Appendix B. Photos of Site Exploration Appendix C. Exploration Logs Appendix D. Laboratory Results 11 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Limitations and Use of This Report Recommendations contained in this report are based on our understanding of the proposed development and construction activities, our field observations and explorations, and our laboratory test results. It is possible that soil and groundwater conditions could vary and differ between or beyond the points explored. If soil or groundwater conditions are encountered during construction that vary or differ from those described herein, we should be notified immediately in order to review and provide supplemental recommendations. If the scope of the proposed construction, including the proposed loads or structural locations, changes from that described in this report, we should be notified to review and provide supplemental recommendations. We have prepared this report in substantial accordance with the generally accepted geotechnical engineering practice as it exists in the site area at the time of our study. No warranty, expressed or implied, is made. The recommendations provided in this report assume that an adequate program of tests and observations will be conducted by MTC during the construction phase in order to evaluate compliance with our recommendations. This report may be used only by the Client and their design consultants and only for the purposes stated within a reasonable time from its issuance, but in no event later than 18 months from the date of the report. It is the Client's responsibility to ensure that the Designer, Contractor, Subcontractors, etc. are made aware of this report in its entirety. Note that if another firm assumes Geotechnical Engineer of Record responsibilities, they need to review this report and either concur with the findings, conclusions, and recommendations or provide alternate findings, conclusions and recommendation under the guidance of a professional engineer registered in the State of Washington. Land or facility use, on- and off-site conditions, regulations, or other factors may change over time, and additional work may be required. Based on the intended use of the report, MTC may recommend that additional work be performed and that an updated report be issued. Non-compliance with any of these requirements by the Client or anyone else will release MTC from any liability resulting from the use of this report. The Client, the design consultants, and any unauthorized party, agree to defend, indemnify, and hold harmless MTC from any claim or liability associated with such unauthorized use or non- compliance. We recommend that MTC be given the opportunity to review the final project plans and specifications to evaluate if our recommendations have been properly interpreted. We assume no responsibility for misinterpretation of our recommendations. The scope of work for this subsurface exploration and geotechnical report did not include environmental assessments or evaluations regarding the presence or absence of wetlands or hazardous substances in the soil, surface water, or groundwater at this site. 12 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix A1. Location and Vicinity Map Site Vicinity Site Location Maps Source: Google Imagery 2019 Materials Testing & Consulting, Site Location & Vicinity FIGURE Inc. Trailer Boss Infiltration Study 777 Chrysler Drive 16523 Smokey Point Blvd 1 Burlington, WA 98233 Arlington, WA 13 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix A2. Site Plan with Test Locations 1 2 TP-4 TP-3 3 TP-6 TP-5 4 TP-2 0 90 MTC 2019 Test Pit Location (approximate) TP-1 Previous Explorations (GCI, 3-24-2016) SCALE (FEET) 1 inch ~ 90 feet Materials Testing & Consulting, Inc. Base Map: Paving Plan â€“ Trailer Boss Site Site Plan with Test Locations FIGURE By: TerraVista NW 8-5-2019 777 Chrysler Drive Trailer Boss Infiltration Study Overlay by MTC: 10-29-2019 2 Burlington, WA 98233 NOT INTENDED FOR CONSTRUCTION 16523 Smokey Point Blvd NOT TO SCALE - Shown is Approximate Arlington, WA 14 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix B. Photos of Site Exploration TP-1 Photo A: Overview of northwestern portion of project site, looking north from the south-central end of proposed improvement area. Note prevalent impediments among middle and north end. Photo B: Overview of southeastern portion of project site, looking southeast from the central transition area of property. No vegetation remains. 15 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 TP-1 Photo C: TP-1 excavation in southeast area. Soil is generally sandy but coarsens with depth. Note mottling in upper subsurface that fades at around 3 feet depth. Groundwater at 5.0 feet BPG. TP-6 Photo D: TP-6 excavation in southwest area of project site. Organic material and disturbed soils observed below imported chipped surfacing to 1.5 feet BPG. Shallow native soils were silty sand, with mottling throughout. Gray sand below about 3.5 feet BPG. Groundwater at 7.0 feet BPG. 16 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix C. Exploration Logs UNIFIED SOIL CLASSIFICATION SYSTEM - USCS LOG SYMBOLS MAJOR DIVISIONS USCS SYMBOL TYPICAL DESCRIPTIONS SAMPLES GW WELL-GRADED GRAVEL SPT Standard Penetration Test < 5% FINES GRAVEL CLEAN GRAVEL Grab or bulk WITH LESS THAN POORLY-GRADED GRAVEL Gravel > Sand 5% FINES GP California or D&M (3.0" OD) < 5% FINES (More than half Shelby Tube of coarse fraction SILTY GRAVEL is larger than GM COARSE GRAVEL > 12% FINES (SILT > CLAY) #4 sieve) GRAINED WITH OVER WATER TABLE SOILS 12% FINES CLAYEY GRAVEL GC Groundwater Level > 12% FINES (CLAY > SILT) (where first encountered) More than half of Groundwater Level material is larger WELL-GRADED SAND CLEAN SAND SW (measured after completion) than the #200 < 5% FINES WITH LESS THAN Perched Groundwater Level sieve SAND 5% FINES (during exploration) SP POORLY-GRADED SAND Silt and / or Clay < 5% FINES Sand > Gravel content as (More than half specified SILTY SAND of coarse fraction SM > 12% FINES (SILT > CLAY) DENSITY: COARSE-GRAINED SOIL is smaller than SAND WITH the #4 sieve) OVER 12% FINES APPARENT SPT SC CLAYEY SAND DENSITY Blows / foot > 12% FINES (CLAY > SILT) Very Loose < 5 INORGANIC SILT; LEAN, LOW PLASTICITY Loose 5 - 10 ML SILT. Medium Dense 11 - 30 Dense 31 - 50 SILT AND CLAY INORGANIC CLAY; LEAN, LOW PLASTICITY Very Dense > 50 FINE CL GRAINED Lean, low to medium plasticity CLAY SOILS (Liquid limit less than 50) ORGANIC SILT & ORGANIC CLAY, OL LEAN, LOW PLASTICITY, DENSITY: FINE-GRAINED SOIL RETAINS VERY HIGH MOISTURE More than half of material is fines INORGANIC SILT, HIGH PLASTICITY, APPARENT SPT (smaller than the MH DENSITY Blows / foot FAT SILT, MAY BE MICACEOUS #200 sieve) SILT AND CLAY Very Soft < 3 CH INORGANIC CLAY, HIGH PLASTICITY, Soft 3 - 4 Sand and / or FAT CLAY Fat, high plasticity Medium Stiff 5 - 8 Gravel content as specified in log (Liquid limit greater than 50) ORGANIC CLAY & ORGANIC SILT Stiff 9 - 15 OH FAT, HIGH PLASTICITY, Very Stiff 16 - 30 RETAINS VERY HIGH MOISTURE Hard > 30 PEAT, HUMUS, SWAMP SOILS, HIGHLY ORGANIC SOILS PT PREDOMINANTLY ORGANIC CONTENT NOTES STRATIGRAPHIC CONTACT USCS evaluated by field observations. Laboratory analyses used when conducted. (approximated by field identification) Poorly-Graded (GP or SP) indicate not an equal content of every grain size subgroup. Distinct stratigraphic Calculated using 10%, 30%, and 60% grain size. contact between soil strata Combination names (e.g. SP-SM Poorly-Graded SAND with silt, represent fines Gradual change between soil strata content between 5% and 12%. Fines content is dominantly either clay (c) or silt (m). Approximate location of A soil description of "with sand" or "with gravel" represents greater than 15% coarse stratigraphic change material, and dominant coarse soil is the one specified. DEFINITIONS OF SOIL FRACTIONS MODIFIERS (see USCS and Notes) SOIL COMPONENT GRAIN SIZE (inch) GRAIN SIZE (metric) DESCRIPTION % Boulder > 12 in. > 305 mm Trace Cobbles 3 in. to 12 in. 75 mm to 305 mm <5% Gravel 3 in. to # 4 sieve 75 mm to 4.75 mm With Clay, With Silt 5 - 12% Fines Coarse Gravel 3 in. to 3/4 in. 75 mm to 19 mm Clayey, Silty >12% Fines Fine Gravel 3/4 in. to # 4 19 mm to 4.75 mm With Sand, With Gravel 15 - 30% Coarse Sand # 4 to # 200 4.75 mm to 0.075 mm Sandy, Gravelly >30% Coarse Coarse # 4 to # 10 4.75 mm to 2 mm Medium # 10 to # 40 2 mm to 0.425 mm Fine # 40 to #200 0.425 mm to 0.075 mm C o p y r ig h t 2 0 1 9 M T C I n c . 3 / 4 / 2 0 1 9 Fines (Silt or Clay) < #200 sieve < 0.075 mm Materials Testing & Consulting, Inc. Exploration Log Key FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 3 Arlington, WA 17 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-1 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : S Center of East lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 SAND WITH SILT to SILTY SAND, trace gravel up to 1/4", fine & medium-grained sand, moist, loose to medium dense, contains moderate organics including 1/2" roots. Light BROWN to TAN-GRAY with light to moderate mottling throughout. 1 SP-SM Local heavy mottling at ~1.6'. 2 SAND WITH GRAVEL, trace silt, moist, loose to medium dense, minor organics including 0.25" roots, gravel up to 1/2" with medium & coarse-grained sand. Medium GRAY. 3 SP 4 Increase in gravel content observed at 4' BPG. 5 Heavy seepage observed at 5' BPG. T.D. @ ~5.3' due to sidewall caving Stabilized water level observed at 5.0' BPG. 6 7 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-1.bor 18 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-2 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : SE corner of E lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 SAND WITH SILT, some gravel up to 1/4", fine & medium-grained sand, moist, loose to medium dense, contains moderate organics including 1/2" roots. Light BROWN to TAN-GRAY with light to moderate mottling throughout, local heavy oxidation staining. 1 SP-SM 2 CEC: 2.6 meq/100 OC: 2% 6.9% 9.1% 3 SAND WITH GRAVEL, trace SILT, gravel up to 1/2", medium & coarse-grained sand, moist, loose to medium dense, contains trace organics and 1/2" roots. Medium GRAY. Increase in gravel content observed at 3.5' BPG. 4 Becomes wet at 4.0' BPG. SP Seepage observed at 4.8' BPG. 5 1.7% 25.9% 6 T.D. @ ~6.2' due to sidewall caving Stabilized water level observed at 5.0' BPG. 7 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-2.bor 19 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-3 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : NE area of E lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 SAND WITH SILT AND GRAVEL, gravel up to 1/4", moist, loose to medium dense, contains moderate organics and 1/2" roots. Light BROWN to TAN-GRAY with light to moderate mottling throughout. 1 Local heavy mottling at ~1.0'. Sand observed to coarsen with depth. 2 SP-SM 3 4 SAND WITH GRAVEL, trace silt, moist to wet with depth, loose to medium dense, minor organics including 1/2" roots, gravel up to 1/2" with medium & coarse-grained sand. Medium GRAY. 5 SP Increase in gravel content observed at 5.5' BPG. Becomes wet at 5.5' BPG. 6 Heavy seepage observed at 6.0' BPG. 7 T.D. @ ~7.0' due to sidewall caving Stabilized water level observed at 5.8' BPG. 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-3.bor 20 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-4 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : NW/Ctr of E lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 SAND WITH SILT to SILTY SAND, trace gravel up to 1/4", fine & medium-grained sand, moist, loose to medium dense, contains moderate organics including 1/2" roots. Light BROWN to TAN-GRAY with moderate mottling becoming lighter with depth. 1 Excavated soils exhibit some cohesion and blocky habit at 1.5' BPG. SP-SM 2 3 CEC: 2.2 meq/100 OC: 1.6% 7.3% 8.0% SAND WITH GRAVEL, trace silt, moist to wet with depth, loose to medium dense, minor 4 organics including 1/2" roots, gravel up to 1" with medium & coarse-grained sand. Medium GRAY with faint mottling. 5 SP 6 Becomes wet at 6.7' BPG. 7 Seepage observed at 7.0' BPG. SP-SM SAND WITH SILT to SILTY SAND, fine-grained sand, wet, medium dense, exhibits some cohesion and blocky habit when excavated. Medium GRAY. 8 T.D. @ ~7.7' due to sidewall caving Stabilized water level observed at 7.0' BPG. 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-4.bor 21 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-5 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : South Central transition area (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 GW Chipped GRAVEL Imported Surfacing Material SAND WITH SILT, moist, loose, contains organics including carbonized wood and roots up to 1/2" thick. Light BROWN to dark REDDISH BROWN, variable. SP-SM Apparent reworked native fill 1 SILTY SAND, some gravel, moist, loose to medium dense, contains moderate organics including some 1/2" roots. Light BROWN to TAN-GRAY with moderate mottling becoming lighter with depth. 2 Excavated soils exhibit some cohesion and blocky habit at 2.0' BPG. SM 3 SAND WITH GRAVEL, trace silt, moist to wet with depth, medium dense, minor organics 4 including 1/2" roots, gravel up to 1" with medium & coarse-grained sand. Medium GRAY with faint mottling. 1.5% 30.7% 5 Gravel content observed to increase with depth. SP 6 Seepage observed at 6.5' BPG. 7 T.D. @ ~7.5' due to sidewall caving Stabilized water level observed at 6.5' BPG. 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-5.bor 22 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 MATERIALS TESTING & CONSULTING Log of Test Pit TP-6 777 Chrysler Drive, Burlington, WA GEOTECHNICAL SERVICES Trailer Boss Stormwater & Mounding Eval Date Started : 10/17/19 16532 Smokey Point Boulevard Date Completed : 10/17/19 Arlington, WA Sampling Method : Grab Samples Location : South Central part of W lot (See Map) MTC Job # 19B335 Logged By : Mike Furman DESCRIPTION Depth in FeetUSCS GRAPHIC Water LevelSample% Finer than #200% Moisture 0 GW Chipped GRAVEL, Imported Surfacing Material SAND WITH SILT, moist, loose, contains organics including carbonized wood and roots up to 1/2" thick. Light BROWN to dark REDDISH BROWN, variable. SP-SM Apparent reworked native fill 1 SILTY SAND, some gravel, moist, loose to medium dense, contains moderate organics including some 1/2" roots. Light BROWN to TAN-GRAY with moderate mottling becoming lighter with depth. 2 CEC: 4.7 meq/100 OC:3.4% 28.8% 25.9% SM 3 Excavated soils exhibit some cohesion and blocky habit at 3.0' BPG. SAND, trace gravel and silt, moist to wet with depth, medium dense, minor organics including 1/2" roots, gravel up to 1" with medium & coarse-grained sand. Medium GRAY with faint mottling. 4 SP 5 SILTY SAND, fine-grained sand, wet, medium dense, blocky habit. Medium GRAY. 25.1% SM SAND, trace gravel and silt, wet, medium dense, minor organics including 1/2" roots, gravel up to 1" with medium & coarse-grained sand. Medium GRAY with faint mottling. 6 SP Seepage observed between 6.5 & 7.0' BPG. 7 T.D. @ ~7.5' due to sidewall caving Stabilized water level observed at 7.0' BPG. 8 10-31-2019 Z:\Burlington Office\Geotechnical Services\1 Burl\2019\Trailer Boss Infiltration\TPLog\TP-6.bor 23 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Appendix D. Laboratory Results Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SP-SM, Poorly graded Sand with Silt Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-2 @ 2.0' Tested By: A. Eifrig brown Sample#: B19-1012 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.054 mm % Gravel = 3.5% Coeff. of Curvature, CC = 0.99 Specifications D(10) = 0.120 mm % Sand = 89.6% Coeff. of Uniformity, CU = 4.80 No Specs D(15) = 0.169 mm % Silt & Clay = 6.9% Fineness Modulus = 2.27 Sample Meets Specs ? N/A D(30) = 0.262 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.386 mm Plasticity Index = n/a Moisture %, as sampled = 9.1% D(60) = 0.578 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 1.785 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 9/73 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 100% 100.0% 0.0% 1.50" 37.50 100% 100.0% 0.0% 1.25" 31.50 100% 100.0% 0.0% 60% 60.0% 1.00" 25.00 100% 100.0% 0.0% 3/4" 19.00 100% 100% 100.0% 0.0% 5/8" 16.00 99% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 98% 98% 100.0% 0.0% 3/8" 9.50 98% 98% 100.0% 0.0% 40% 40.0% 1/4" 6.30 97% 100.0% 0.0% #4 4.75 97% 97% 100.0% 0.0% #8 2.36 95% 100.0% 0.0% 30% 30.0% #10 2.00 95% 95% 100.0% 0.0% #16 1.18 75% 100.0% 0.0% #20 0.850 67% 100.0% 0.0% 20% 20.0% #30 0.600 61% 100.0% 0.0% #40 0.425 56% 56% 100.0% 0.0% 10% 10.0% #50 0.300 36% 100.0% 0.0% #60 0.250 28% 100.0% 0.0% #80 0.180 17% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 12% 12% 100.0% 0.0% #140 0.106 9% 100.0% 0.0% Particle Size (mm) #170 0.090 8% 100.0% 0.0% #200 0.075 6.9% 6.9% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-2 @ 2.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 4a Arlington, WA 24 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Materials Testing & Consulting, Inc. Lab Sample: TP-2 @ 2.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 4b Arlington, WA 25 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SP, Poorly graded Sand Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-2 @ 5.5' Tested By: A. Eifrig brown Sample#: B19-1013 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.128 mm % Gravel = 5.4% Coeff. of Curvature, CC = 0.68 Specifications D(10) = 0.172 mm % Sand = 92.9% Coeff. of Uniformity, CU = 4.19 No Specs D(15) = 0.201 mm % Silt & Clay = 1.7% Fineness Modulus = 2.53 Sample Meets Specs ? N/A D(30) = 0.290 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.409 mm Plasticity Index = n/a Moisture %, as sampled = 25.9% D(60) = 0.719 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 1.930 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 2/63 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 99% 100.0% 0.0% 1.50" 37.50 99% 100.0% 0.0% 1.25" 31.50 98% 100.0% 0.0% 60% 60.0% 1.00" 25.00 97% 97% 100.0% 0.0% 3/4" 19.00 97% 97% 100.0% 0.0% 5/8" 16.00 97% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 97% 97% 100.0% 0.0% 3/8" 9.50 96% 96% 100.0% 0.0% 40% 40.0% 1/4" 6.30 95% 100.0% 0.0% #4 4.75 95% 95% 100.0% 0.0% #8 2.36 92% 100.0% 0.0% 30% 30.0% #10 2.00 92% 92% 100.0% 0.0% #16 1.18 71% 100.0% 0.0% #20 0.850 63% 100.0% 0.0% 20% 20.0% #30 0.600 57% 100.0% 0.0% #40 0.425 53% 53% 100.0% 0.0% 10% 10.0% #50 0.300 32% 100.0% 0.0% #60 0.250 23% 100.0% 0.0% #80 0.180 11% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 6% 6% 100.0% 0.0% #140 0.106 4% 100.0% 0.0% Particle Size (mm) #170 0.090 3% 100.0% 0.0% #200 0.075 1.7% 1.7% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-2 @ 5.5â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 5 Arlington, WA 26 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SP-SM, Poorly graded Sand with Silt Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-4 @ 3.0' Tested By: A. Eifrig brown Sample#: B19-1014 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.051 mm % Gravel = 0.0% Coeff. of Curvature, CC = 1.30 Specifications D(10) = 0.092 mm % Sand = 92.7% Coeff. of Uniformity, CU = 3.25 No Specs D(15) = 0.123 mm % Silt & Clay = 7.3% Fineness Modulus = 1.28 Sample Meets Specs ? N/A D(30) = 0.189 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.262 mm Plasticity Index = n/a Moisture %, as sampled = 8.0% D(60) = 0.299 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 0.408 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 1/13 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 100% 100.0% 0.0% 1.50" 37.50 100% 100.0% 0.0% 1.25" 31.50 100% 100.0% 0.0% 60% 60.0% 1.00" 25.00 100% 100.0% 0.0% 3/4" 19.00 100% 100.0% 0.0% 5/8" 16.00 100% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 100% 100% 100.0% 0.0% 3/8" 9.50 100% 100% 100.0% 0.0% 40% 40.0% 1/4" 6.30 100% 100.0% 0.0% #4 4.75 100% 100% 100.0% 0.0% #8 2.36 100% 100.0% 0.0% 30% 30.0% #10 2.00 100% 100% 100.0% 0.0% #16 1.18 97% 100.0% 0.0% #20 0.850 96% 100.0% 0.0% 20% 20.0% #30 0.600 95% 100.0% 0.0% #40 0.425 95% 95% 100.0% 0.0% 10% 10.0% #50 0.300 60% 100.0% 0.0% #60 0.250 47% 100.0% 0.0% #80 0.180 28% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 19% 19% 100.0% 0.0% #140 0.106 12% 100.0% 0.0% Particle Size (mm) #170 0.090 10% 100.0% 0.0% #200 0.075 7.3% 7.3% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-4 @ 3.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 6a Arlington, WA 27 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Materials Testing & Consulting, Inc. Lab Sample: TP-4 @ 3.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 6b Arlington, WA 28 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SP, Poorly graded Sand Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-5 @ 4.0' Tested By: A. Eifrig brown Sample#: B19-1015 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.108 mm % Gravel = 0.2% Coeff. of Curvature, CC = 1.01 Specifications D(10) = 0.152 mm % Sand = 98.3% Coeff. of Uniformity, CU = 2.35 No Specs D(15) = 0.173 mm % Silt & Clay = 1.5% Fineness Modulus = 1.80 Sample Meets Specs ? N/A D(30) = 0.234 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.317 mm Plasticity Index = n/a Moisture %, as sampled = 30.7% D(60) = 0.358 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 1.372 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 1/50 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 100% 100.0% 0.0% 1.50" 37.50 100% 100.0% 0.0% 1.25" 31.50 100% 100.0% 0.0% 60% 60.0% 1.00" 25.00 100% 100.0% 0.0% 3/4" 19.00 100% 100.0% 0.0% 5/8" 16.00 100% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 100% 100% 100.0% 0.0% 3/8" 9.50 100% 100% 100.0% 0.0% 40% 40.0% 1/4" 6.30 100% 100.0% 0.0% #4 4.75 100% 100% 100.0% 0.0% #8 2.36 99% 100.0% 0.0% 30% 30.0% #10 2.00 99% 99% 100.0% 0.0% #16 1.18 87% 100.0% 0.0% #20 0.850 82% 100.0% 0.0% 20% 20.0% #30 0.600 79% 100.0% 0.0% #40 0.425 76% 76% 100.0% 0.0% 10% 10.0% #50 0.300 46% 100.0% 0.0% #60 0.250 34% 100.0% 0.0% #80 0.180 17% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 9% 9% 100.0% 0.0% #140 0.106 5% 100.0% 0.0% Particle Size (mm) #170 0.090 3% 100.0% 0.0% #200 0.075 1.5% 1.5% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-5 @ 4.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 7 Arlington, WA 29 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Sieve Report Project: Trailer Boss Infiltration & Mounding Study Date Received: 22-Oct-19 ASTM D-2487 Unified Soils Classification System Project #: 19B335 Sampled By: M. Furman SM, Silty Sand Client: Terra Vista NW, LLC Date Tested: 23-Oct-19 Sample Color: Source: TP-6 @ 2.0' Tested By: A. Eifrig brown Sample#: B19-1016 ASTM D-2216, ASTM D-2419, ASTM D-4318, ASTM D-5821 D(5) = 0.013 mm % Gravel = 0.4% Coeff. of Curvature, CC = 1.14 Specifications D(10) = 0.026 mm % Sand = 70.7% Coeff. of Uniformity, CU = 8.09 No Specs D(15) = 0.039 mm % Silt & Clay = 28.8% Fineness Modulus = 0.86 Sample Meets Specs ? N/A D(30) = 0.079 mm Liquid Limit = n/a Plastic Limit = n/a D(50) = 0.148 mm Plasticity Index = n/a Moisture %, as sampled = 25.9% D(60) = 0.211 mm Sand Equivalent = n/a Req'd Sand Equivalent = D(90) = 0.404 mm Fracture %, 1 Face = n/a Req'd Fracture %, 1 Face = Dust Ratio = 30/97 Fracture %, 2+ Faces = n/a Req'd Fracture %, 2+ Faces = ASTM C-136, ASTM D-6913 Actual Interpolated Cumulative Cumulative Grain Size Dist ribution Sieve Size Percent Percent Specs Specs 1Â¼"Â¾"Â½" US Metric Passing Passing Max Min 10"8"6" 4"3" 2"1Â½"1" 5/8"3/8"Â¼"#4 #8#10#16#20#30#40#50#60#80#100#140#170#200 100% 100.0% 12.00" 300.00 100% 100.0% 0.0% 10.00" 250.00 100% 100.0% 0.0% 8.00" 200.00 100% 100.0% 0.0% 90% 90.0% 6.00" 150.00 100% 100.0% 0.0% 4.00" 100.00 100% 100.0% 0.0% 3.00" 75.00 100% 100.0% 0.0% 80% 80.0% 2.50" 63.00 100% 100.0% 0.0% 2.00" 50.00 100% 100% 100.0% 0.0% 70% 70.0% 1.75" 45.00 100% 100.0% 0.0% 1.50" 37.50 100% 100.0% 0.0% 1.25" 31.50 100% 100.0% 0.0% 60% 60.0% 1.00" 25.00 100% 100.0% 0.0% 3/4" 19.00 100% 100.0% 0.0% 5/8" 16.00 100% 100.0% 0.0% % Passing 50% 50.0% % Passing 1/2" 12.50 100% 100% 100.0% 0.0% 3/8" 9.50 100% 100% 100.0% 0.0% 40% 40.0% 1/4" 6.30 100% 100.0% 0.0% #4 4.75 100% 100% 100.0% 0.0% #8 2.36 99% 100.0% 0.0% 30% 30.0% #10 2.00 99% 99% 100.0% 0.0% #16 1.18 96% 100.0% 0.0% #20 0.850 95% 100.0% 0.0% 20% 20.0% #30 0.600 94% 100.0% 0.0% #40 0.425 93% 93% 100.0% 0.0% 10% 10.0% #50 0.300 74% 100.0% 0.0% #60 0.250 66% 100.0% 0.0% #80 0.180 55% 100.0% 0.0% 0% 0.0% 100.000 10.000 1.000 0.100 0.010 0.001 #100 0.150 51% 51% 100.0% 0.0% #140 0.106 38% 100.0% 0.0% Particle Size (mm) #170 0.090 33% 100.0% 0.0% #200 0.075 28.8% 28.8% 100.0% 0.0% Sieve Sizes Max Specs Min Specs Sieve Results Copyrig ht Spears Engineering & Technical Services PS, 199 6-98 All results apply only to actual lo cations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the co nfidential property of clients, and authorization for p ublicatio n of statements, conclusions or extracts from o r regarding our repo rts is reserved pending our written approval. Comments: Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-6 @ 2.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 8a Arlington, WA 30 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Materials Testing & Consulting, Inc. Lab Sample: TP-6 @ 2.0â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 8b Arlington, WA 31 Trailer Boss Infiltration Assessment, Arlington, WA Materials Testing & Consulting, Inc. November 15, 2019 19B335 Materials Testing & Consulting, Inc. Geotechnical Engineering â€¢ Special Inspection â€¢ Materials Testing â€¢ Environmental Consulting Project: Trailer Boss Infiltration & Mounding Study Client: Terra Vista NW, LLC Project #: 19B335 Date Received: October 22, 2019 Sampled by: M. Furman Date Tested: October 23, 2019 Tested by: A. Eifrig Amount of Materials Finer Than #200 Sieve - ASTM C-117, ASTM D-1140 & AASHTO T-11 Sample # Location Tare Before Wash + Tare After Wash + Tare Amount of Loss % -#200 B19-1017 TP-6 @ 5.2' 731.4 1743.9 1489.5 254.4 25.1% 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! 0.0 #DIV/0! All results apply only to actual locatio ns and materials tested. As a mutual protectio n to clients, the public and ourselves, all reports are submitted as the confidential p rop erty of clients, and authorization for publication of statements, conclusions or extracts from or regarding our rep orts is reserved pending our written approval. Reviewed by: Meghan Blodgett-Carrillo Materials Testing & Consulting, Inc. Lab Sample: TP-6 @ 5.2â€™ FIGURE 777 Chrysler Drive Trailer Boss Infiltration Study Burlington, WA 98233 16523 Smokey Point Blvd 9 Arlington, WA 32 TerraVista NW,LLC Appendix C Operation and Maintenance TerraVista NW,LLC Operation and Maintenance Procedures The following maintenance standards are as described in Volume V, Section 4.6.6, Table 5.3 of the SWMMWW. Table V-4.5.2(2) Maintenance Standards - Infiltration Maintenance Defect Conditions When Maintenance Results Expected When Component Is Needed Maintenance Is Performed General Trash & Debris See "Detention Ponds" (No. 1). See "Detention Ponds" (No. 1). Poisonous/Noxious See "Detention Ponds" (No. 1). See "Detention Ponds" Vegetation (No. 1). Contaminants and See "Detention Ponds" (No. 1). See "Detention Ponds" Pollution (No. 1). Rodent Holes See "Detention Ponds" (No. 1). See "Detention Ponds" (No. 1). Storage Area Sediment Water ponding in infiltration pond Sediment is removed after rainfall ceases and appropriate and/or facility is cleaned timeallowed for infiltration. so that infiltration system Treatment basins should infiltrate works according to design. Water Quality Design Storm Volume within 48 hours, and empty within 24 hours after cessation of most rain events TerraVista NW,LLC Operation and Maintenance Procedures (A percolation test pit or test of facility indicates facility is only working at 90% of its designed capabilities. Test every 2 to 5 years. If two inches or more sediment is present, remove). Filter Bags (if Filled with Sediment and debris fill bag more Filter bag is replaced or applicable) Sediment and than 1/2 full. system is redesigned. Debris Rock Filters Sediment and By visual inspection, little or no Gravel in rock filter is Debris water flows through filter during replaced. heavy rain storms. Side Slopes of Erosion See "Detention Ponds" (No. 1). See "Detention Ponds" Pond (No. 1). Emergency Tree Growth See "Detention Ponds" (No. 1). See "Detention Ponds" Overflow Spillway (No. 1). and Berms over 4 Piping See "Detention Ponds" (No. 1). See "Detention Ponds" feet in height. (No. 1). Emergency Rock Missing See "Detention Ponds" (No. 1). See "Detention Ponds" Overflow Spillway (No. 1). Erosion See "Detention Ponds" (No. 1). See "Detention Ponds" (No. 1). Pre-settling Ponds Facility or sump 6" or designed sediment trap depth Sediment is removed. and Vaults filled with Sediment of sediment. and/or debris TerraVista NW,LLC Operation and Maintenance Procedures Table V-4.5.2(5) Maintenance Standards - Catch Basins Maintenance Defect Conditions When Maintenance Is Needed Results Expected Component When Maintenance Is Performed General Trash and Debris Trash or debris which is located immediately No Trash or debris in front of the catch basin opening or is located immediately in blocking inletting capacity of the basin by front of catch basin or more than 10%. on grate opening. Trash or debris (in the basin) that exceeds 60 No trash or debris in percent of the sump depth as measured from the the bottom of basin to invert of the lowest catch basin. pipe into or out of the basin, but in no case less than a minimum of six inches clearance from the debris surface to the invert of the lowest pipe. Trash or debris in any inlet or outlet pipe Inlet and outlet pipes blocking more than 1/3 of its height. free of trash or debris. Dead animals or vegetation that could No dead animals or generate odors that could cause complaints vegetation present or dangerous gases (e.g., methane). within the catch basin. TerraVista NW,LLC Operation and Maintenance Procedures Sediment Sediment (in the basin) that exceeds 60 No sediment in the percent of the sump depth as measured from catch basin the bottom of basin to invert of the lowest pipe into or out of the basin, but in no case less than a minimum of 6 inches clearance from the sediment surface to the invert of the lowest pipe. Structure Damage Top slab has holes larger than 2 square Top slab is free of to Frame and/or inches or cracks wider than 1/4 inch holes Top Slab (Intent is to make sure no material is running and cracks into basin). Frame not sitting flush on top slab, i.e., Frame is sitting flush separation of more than 3/4 inch of the frame on the riser rings or top from the top slab. Frame not securely slab and firmly attached attached. Fractures or Cracks Maintenance person judges that structure is Basin replaced or in Basin unsound. repaired to design Walls/Bottom standards. Grout fillet has separated or cracked wider Pipe is regrouted and than 1/2 inch and longer than 1 foot at the secure at basin wall. joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. Settlement/ If failure of basin has created a safety, Basin replaced or Misalignment function, or design problem. repaired to design standards. TerraVista NW,LLC Operation and Maintenance Procedures Vegetation Vegetation growing across and blocking No vegetation blocking more opening to basin. than 10% of the basin opening. Vegetation growing in inlet/outlet pipe joints No vegetation or root that is more than six inches tall and less than growth present six inches apart. Contamination and See "Detention Ponds" (No. 1). No pollution present. Pollution Catch Basin Cover Not in Place Cover is missing or only partially in place. Catch basincover is Cover Any open catch basin requires maintenance. closed Locking Mechanism cannot be opened by one Mechanism opens with Mechanism Not maintenance person with proper tools. Bolts proper tools. Working into frame have less than 1/2 inch of thread. Cover Difficult to One maintenance person cannot remove lid Cover can be removed Remove after applying normal lifting pressure. by one maintenance (Intent is keep cover from sealing off access person. to maintenance.) Ladder Latter Rungs Ladder is unsafe due to missingrungs, not Ladder meets design Unsafe securely attached to basin wall, standards and allows misalignment, rust, cracks, or sharp edges. maintenance person safe access. Metal Grates Grate Opening Grate with opening wider than 7/8 inch. Grate opening meets (If Applicable) Unsafe design standards. Trash and Debris Trash and debris that is blocking more than Grate free of trash and 20% of grate surface inletting capacity. debris. Damaged or Grate missing or broken member(s) of the Grate is in place and Missing grate. meets design standards. TerraVista NW,LLC Operation and Maintenance Procedures Table V-4.5.2(18) Maintenance Standards - Catchbasin Inserts Maintenance Defect Conditions When Maintenance Is Results Expected When Component Needed Maintenance is Performed General Sediment When sediment forms a cap over No sediment cap on the insert Accumulation the media and its unit. insert media of the insert and/or unit. Trash and Debris Trash and debris accumulates on Trash and debris removed Accumulation insert unit creating a from insert unit. Runoff freely blockage/restriction. flows into catch basin. Media Insert Not Effluent water from media insert Effluent water from media Removing Oil has a visible sheen. insert is free of oils and has no visible sheen. Media Insert Water Catch basin insert is saturated with Remove and replace media Saturated water and no longer has the insert. capacity to absorb. Media Insert-Oil Media oil saturated due to Remove and replace media Saturated petroleum spill that drains into insert. catch basin. Media Insert Use Media has been used beyond the Remove and replace media at Beyond Normal typical average life of media insert regular intervals, depending on Product Life product. insert product. TerraVista NW,LLC Appendix D Infiltration Trench Drainage Calculations WWHM2012 PROJECT REPORT General Model Information Project Name: 2020-02-28-WWHM2012_TB Total Area Infil Site Name: TB Trench Area Site Address: 16523 Smokey Pt Blvd City: Arlington Report Date: 2/28/2020 Gage: Everett Data Start: 1948/10/01 Data End: 2009/09/30 Timestep: 15 Minute Precip Scale: 1.200 Version Date: 2019/09/13 Version: 4.2.17 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:34 PM Page 2 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass: No GroundWater: No Pervious Land Use acre A B, Forest, Flat 2.28 Pervious Total 2.28 Impervious Land Use acre Impervious Total 0 Basin Total 2.28 Element Flows To: Surface Interflow Groundwater 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:34 PM Page 3 Mitigated Land Use Basin 1 Bypass: No GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 2.28 Impervious Total 2.28 Basin Total 2.28 Element Flows To: Surface Interflow Groundwater Gravel Trench Bed 1 Gravel Trench Bed 1 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:34 PM Page 4 Routing Elements Predeveloped Routing 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:34 PM Page 5 Mitigated Routing Gravel Trench Bed 1 Bottom Length: 1050.00 ft. Bottom Width: 5.00 ft. Trench bottom slope 1: 0.001 To 1 Trench Left side slope 0: 0.001 To 1 Trench right side slope 2: 0.001 To 1 Material thickness of first layer: 2 Pour Space of material for first layer: 0.33 Material thickness of second layer: 0 Pour Space of material for second layer: 0 Material thickness of third layer: 0 Pour Space of material for third layer: 0 Infiltration On Infiltration rate: 10 Infiltration safety factor: 1 Wetted surface area On Total Volume Infiltrated (ac-ft.): 440.783 Total Volume Through Riser (ac-ft.): 0.01 Total Volume Through Facility (ac-ft.): 440.794 Percent Infiltrated: 100 Total Precip Applied to Facility: 0 Total Evap From Facility: 0 Discharge Structure Riser Height: 2 ft. Riser Diameter: 12 in. Element Flows To: Outlet 1 Outlet 2 Gravel Trench Bed Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.120 0.000 0.000 0.000 0.0222 0.120 0.000 0.000 1.215 0.0444 0.120 0.001 0.000 1.215 0.0667 0.120 0.002 0.000 1.215 0.0889 0.120 0.003 0.000 1.215 0.1111 0.120 0.004 0.000 1.215 0.1333 0.120 0.005 0.000 1.215 0.1556 0.120 0.006 0.000 1.215 0.1778 0.120 0.007 0.000 1.215 0.2000 0.120 0.008 0.000 1.215 0.2222 0.120 0.008 0.000 1.215 0.2444 0.120 0.009 0.000 1.215 0.2667 0.120 0.010 0.000 1.215 0.2889 0.120 0.011 0.000 1.215 0.3111 0.120 0.012 0.000 1.215 0.3333 0.120 0.013 0.000 1.215 0.3556 0.120 0.014 0.000 1.215 0.3778 0.120 0.015 0.000 1.215 0.4000 0.120 0.015 0.000 1.215 0.4222 0.120 0.016 0.000 1.215 0.4444 0.120 0.017 0.000 1.215 0.4667 0.120 0.018 0.000 1.215 0.4889 0.120 0.019 0.000 1.215 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:34 PM Page 6 0.5111 0.120 0.020 0.000 1.215 0.5333 0.120 0.021 0.000 1.215 0.5556 0.120 0.022 0.000 1.215 0.5778 0.120 0.023 0.000 1.215 0.6000 0.120 0.023 0.000 1.215 0.6222 0.120 0.024 0.000 1.215 0.6444 0.120 0.025 0.000 1.215 0.6667 0.120 0.026 0.000 1.215 0.6889 0.120 0.027 0.000 1.215 0.7111 0.120 0.028 0.000 1.215 0.7333 0.120 0.029 0.000 1.215 0.7556 0.120 0.030 0.000 1.215 0.7778 0.120 0.030 0.000 1.215 0.8000 0.120 0.031 0.000 1.215 0.8222 0.120 0.032 0.000 1.215 0.8444 0.120 0.033 0.000 1.215 0.8667 0.120 0.034 0.000 1.215 0.8889 0.120 0.035 0.000 1.215 0.9111 0.120 0.036 0.000 1.215 0.9333 0.120 0.037 0.000 1.215 0.9556 0.120 0.038 0.000 1.215 0.9778 0.120 0.038 0.000 1.215 1.0000 0.120 0.039 0.000 1.215 1.0222 0.120 0.040 0.000 1.215 1.0444 0.120 0.041 0.000 1.215 1.0667 0.120 0.042 0.000 1.215 1.0889 0.120 0.043 0.000 1.215 1.1111 0.120 0.044 0.000 1.215 1.1333 0.120 0.045 0.000 1.215 1.1556 0.120 0.046 0.000 1.215 1.1778 0.120 0.046 0.000 1.215 1.2000 0.120 0.047 0.000 1.215 1.2222 0.120 0.048 0.000 1.215 1.2444 0.120 0.049 0.000 1.215 1.2667 0.120 0.050 0.000 1.215 1.2889 0.120 0.051 0.000 1.215 1.3111 0.120 0.052 0.000 1.215 1.3333 0.120 0.053 0.000 1.215 1.3556 0.120 0.053 0.000 1.215 1.3778 0.120 0.054 0.000 1.216 1.4000 0.120 0.055 0.000 1.216 1.4222 0.120 0.056 0.000 1.216 1.4444 0.120 0.057 0.000 1.216 1.4667 0.120 0.058 0.000 1.216 1.4889 0.120 0.059 0.000 1.216 1.5111 0.120 0.060 0.000 1.216 1.5333 0.120 0.061 0.000 1.216 1.5556 0.120 0.061 0.000 1.216 1.5778 0.120 0.062 0.000 1.216 1.6000 0.120 0.063 0.000 1.216 1.6222 0.120 0.064 0.000 1.216 1.6444 0.120 0.065 0.000 1.216 1.6667 0.120 0.066 0.000 1.216 1.6889 0.120 0.067 0.000 1.216 1.7111 0.120 0.068 0.000 1.216 1.7333 0.120 0.069 0.000 1.216 1.7556 0.120 0.069 0.000 1.216 1.7778 0.120 0.070 0.000 1.216 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:34 PM Page 7 1.8000 0.120 0.071 0.000 1.216 1.8222 0.120 0.072 0.000 1.216 1.8444 0.120 0.073 0.000 1.216 1.8667 0.120 0.074 0.000 1.216 1.8889 0.120 0.075 0.000 1.216 1.9111 0.120 0.076 0.000 1.216 1.9333 0.120 0.076 0.000 1.216 1.9556 0.120 0.077 0.000 1.216 1.9778 0.120 0.078 0.000 1.216 2.0000 0.120 0.079 0.000 1.216 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:34 PM Page 8 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area: 2.28 Total Impervious Area: 0 Mitigated Landuse Totals for POC #1 Total Pervious Area: 0 Total Impervious Area: 2.28 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.002617 5 year 0.005676 10 year 0.009105 25 year 0.015901 50 year 0.023497 100 year 0.034084 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0 5 year 0 10 year 0 25 year 0 50 year 0 100 year 0 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.002 0.000 1950 0.005 0.000 1951 0.004 0.000 1952 0.002 0.000 1953 0.002 0.000 1954 0.013 0.000 1955 0.010 0.000 1956 0.002 0.000 1957 0.002 0.000 1958 0.002 0.000 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:34 PM Page 9 1959 0.004 0.000 1960 0.003 0.000 1961 0.009 0.208 1962 0.002 0.000 1963 0.002 0.000 1964 0.006 0.000 1965 0.002 0.000 1966 0.002 0.000 1967 0.004 0.000 1968 0.002 0.000 1969 0.002 0.000 1970 0.002 0.000 1971 0.009 0.000 1972 0.002 0.000 1973 0.002 0.000 1974 0.005 0.000 1975 0.002 0.000 1976 0.004 0.000 1977 0.002 0.000 1978 0.002 0.000 1979 0.004 0.000 1980 0.002 0.000 1981 0.002 0.000 1982 0.003 0.000 1983 0.002 0.000 1984 0.002 0.000 1985 0.003 0.000 1986 0.016 0.000 1987 0.011 0.000 1988 0.002 0.000 1989 0.002 0.000 1990 0.002 0.000 1991 0.002 0.000 1992 0.002 0.000 1993 0.002 0.000 1994 0.002 0.000 1995 0.002 0.000 1996 0.021 0.000 1997 0.056 0.000 1998 0.002 0.000 1999 0.002 0.000 2000 0.003 0.000 2001 0.002 0.000 2002 0.002 0.000 2003 0.001 0.000 2004 0.002 0.000 2005 0.002 0.000 2006 0.061 0.000 2007 0.002 0.000 2008 0.003 0.000 2009 0.002 0.000 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0607 0.2085 2 0.0564 0.0000 3 0.0206 0.0000 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:59 PM Page 10 4 0.0160 0.0000 5 0.0126 0.0000 6 0.0105 0.0000 7 0.0095 0.0000 8 0.0089 0.0000 9 0.0086 0.0000 10 0.0060 0.0000 11 0.0053 0.0000 12 0.0048 0.0000 13 0.0041 0.0000 14 0.0041 0.0000 15 0.0038 0.0000 16 0.0036 0.0000 17 0.0036 0.0000 18 0.0034 0.0000 19 0.0033 0.0000 20 0.0031 0.0000 21 0.0028 0.0000 22 0.0027 0.0000 23 0.0022 0.0000 24 0.0018 0.0000 25 0.0018 0.0000 26 0.0018 0.0000 27 0.0018 0.0000 28 0.0018 0.0000 29 0.0018 0.0000 30 0.0018 0.0000 31 0.0018 0.0000 32 0.0018 0.0000 33 0.0018 0.0000 34 0.0018 0.0000 35 0.0018 0.0000 36 0.0018 0.0000 37 0.0018 0.0000 38 0.0018 0.0000 39 0.0018 0.0000 40 0.0018 0.0000 41 0.0018 0.0000 42 0.0018 0.0000 43 0.0018 0.0000 44 0.0018 0.0000 45 0.0018 0.0000 46 0.0018 0.0000 47 0.0018 0.0000 48 0.0018 0.0000 49 0.0018 0.0000 50 0.0018 0.0000 51 0.0018 0.0000 52 0.0018 0.0000 53 0.0018 0.0000 54 0.0018 0.0000 55 0.0018 0.0000 56 0.0018 0.0000 57 0.0018 0.0000 58 0.0018 0.0000 59 0.0017 0.0000 60 0.0016 0.0000 61 0.0013 0.0000 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:59 PM Page 11 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:59 PM Page 12 Duration Flows The Facility PASSED Flow(cfs) Predev Mit Percentage Pass/Fail 0.0013 2357 4 0 Pass 0.0015 1327 4 0 Pass 0.0018 434 4 0 Pass 0.0020 112 4 3 Pass 0.0022 102 4 3 Pass 0.0024 89 4 4 Pass 0.0027 77 4 5 Pass 0.0029 66 4 6 Pass 0.0031 61 4 6 Pass 0.0033 58 4 6 Pass 0.0035 54 4 7 Pass 0.0038 50 4 8 Pass 0.0040 49 4 8 Pass 0.0042 47 4 8 Pass 0.0044 43 4 9 Pass 0.0047 40 4 10 Pass 0.0049 36 4 11 Pass 0.0051 36 4 11 Pass 0.0053 32 4 12 Pass 0.0056 31 4 12 Pass 0.0058 31 4 12 Pass 0.0060 29 4 13 Pass 0.0062 29 4 13 Pass 0.0065 27 4 14 Pass 0.0067 26 4 15 Pass 0.0069 26 4 15 Pass 0.0071 26 4 15 Pass 0.0074 25 4 16 Pass 0.0076 23 4 17 Pass 0.0078 23 4 17 Pass 0.0080 23 4 17 Pass 0.0083 23 4 17 Pass 0.0085 23 4 17 Pass 0.0087 21 4 19 Pass 0.0089 19 4 21 Pass 0.0092 18 4 22 Pass 0.0094 17 4 23 Pass 0.0096 16 4 25 Pass 0.0098 16 4 25 Pass 0.0100 15 4 26 Pass 0.0103 15 4 26 Pass 0.0105 14 4 28 Pass 0.0107 13 4 30 Pass 0.0109 13 4 30 Pass 0.0112 13 4 30 Pass 0.0114 13 4 30 Pass 0.0116 13 4 30 Pass 0.0118 13 4 30 Pass 0.0121 13 4 30 Pass 0.0123 13 4 30 Pass 0.0125 13 4 30 Pass 0.0127 11 4 36 Pass 0.0130 11 4 36 Pass 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:59 PM Page 13 0.0132 11 4 36 Pass 0.0134 11 4 36 Pass 0.0136 11 4 36 Pass 0.0139 11 4 36 Pass 0.0141 11 4 36 Pass 0.0143 11 4 36 Pass 0.0145 11 4 36 Pass 0.0148 11 4 36 Pass 0.0150 11 4 36 Pass 0.0152 11 4 36 Pass 0.0154 11 4 36 Pass 0.0157 10 4 40 Pass 0.0159 10 4 40 Pass 0.0161 9 4 44 Pass 0.0163 9 4 44 Pass 0.0165 8 4 50 Pass 0.0168 8 4 50 Pass 0.0170 8 4 50 Pass 0.0172 8 4 50 Pass 0.0174 8 4 50 Pass 0.0177 8 4 50 Pass 0.0179 8 4 50 Pass 0.0181 8 4 50 Pass 0.0183 8 4 50 Pass 0.0186 8 4 50 Pass 0.0188 8 4 50 Pass 0.0190 8 4 50 Pass 0.0192 8 4 50 Pass 0.0195 8 4 50 Pass 0.0197 8 4 50 Pass 0.0199 7 4 57 Pass 0.0201 7 4 57 Pass 0.0204 7 4 57 Pass 0.0206 7 4 57 Pass 0.0208 6 4 66 Pass 0.0210 6 4 66 Pass 0.0213 6 4 66 Pass 0.0215 6 4 66 Pass 0.0217 6 4 66 Pass 0.0219 6 4 66 Pass 0.0222 6 4 66 Pass 0.0224 6 4 66 Pass 0.0226 6 4 66 Pass 0.0228 6 4 66 Pass 0.0230 6 4 66 Pass 0.0233 5 4 80 Pass 0.0235 5 4 80 Pass 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:59 PM Page 14 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0 acre-feet On-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. Off-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:59 PM Page 15 LID Report 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:31:59 PM Page 16 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:05 PM Page 17 Appendix Predeveloped Schematic 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:05 PM Page 18 Mitigated Schematic 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:05 PM Page 19 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 2020-02-28-WWHM2012_TB Total Area Infil.wdm MESSU 25 Pre2020-02-28-WWHM2012_TB Total Area Infil.MES 27 Pre2020-02-28-WWHM2012_TB Total Area Infil.L61 28 Pre2020-02-28-WWHM2012_TB Total Area Infil.L62 30 POC2020-02-28-WWHM2012_TB Total Area Infil1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 A/B, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 1 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 1 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 20 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 1 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 1 0 5 2 400 0.05 0.3 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 1 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 1 0.2 0.5 0.35 0 0.7 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 1 0 0 0 0 3 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 21 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 1 2.28 COPY 501 12 PERLND 1 2.28 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1.2 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1.2 IMPLND 1 999 EXTNL PREC 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 22 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 23 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 2020-02-28-WWHM2012_TB Total Area Infil.wdm MESSU 25 Mit2020-02-28-WWHM2012_TB Total Area Infil.MES 27 Mit2020-02-28-WWHM2012_TB Total Area Infil.L61 28 Mit2020-02-28-WWHM2012_TB Total Area Infil.L62 30 POC2020-02-28-WWHM2012_TB Total Area Infil1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 IMPLND 1 RCHRES 1 COPY 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Gravel Trench Bed 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* END PRINT-INFO PWAT-PARM1 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 24 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATE1 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 25 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** IMPLND 1 2.28 RCHRES 1 5 ******Routing****** IMPLND 1 2.28 COPY 1 15 RCHRES 1 1 COPY 501 17 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Gravel Trench Be-005 2 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 5 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.2 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 26 FTABLES FTABLE 1 92 5 Depth Area Volume Outflow1 Outflow2 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (cfs) (ft/sec) (Minutes)*** 0.000000 0.120523 0.000000 0.000000 0.000000 0.022222 0.120524 0.000884 0.000000 1.215289 0.044444 0.120526 0.001768 0.000000 1.215299 0.066667 0.120527 0.002652 0.000000 1.215310 0.088889 0.120528 0.003535 0.000000 1.215321 0.111111 0.120529 0.004419 0.000000 1.215332 0.133333 0.120530 0.005303 0.000000 1.215343 0.155556 0.120531 0.006187 0.000000 1.215354 0.177778 0.120532 0.007071 0.000000 1.215365 0.200000 0.120533 0.007955 0.000000 1.215375 0.222222 0.120534 0.008839 0.000000 1.215386 0.244444 0.120535 0.009723 0.000000 1.215397 0.266667 0.120536 0.010607 0.000000 1.215408 0.288889 0.120537 0.011491 0.000000 1.215419 0.311111 0.120538 0.012375 0.000000 1.215430 0.333333 0.120540 0.013258 0.000000 1.215441 0.355556 0.120541 0.014142 0.000000 1.215451 0.377778 0.120542 0.015026 0.000000 1.215462 0.400000 0.120543 0.015910 0.000000 1.215473 0.422222 0.120544 0.016794 0.000000 1.215484 0.444444 0.120545 0.017678 0.000000 1.215495 0.466667 0.120546 0.018562 0.000000 1.215506 0.488889 0.120547 0.019446 0.000000 1.215517 0.511111 0.120548 0.020330 0.000000 1.215527 0.533333 0.120549 0.021214 0.000000 1.215538 0.555556 0.120550 0.022098 0.000000 1.215549 0.577778 0.120551 0.022982 0.000000 1.215560 0.600000 0.120552 0.023867 0.000000 1.215571 0.622222 0.120554 0.024751 0.000000 1.215582 0.644444 0.120555 0.025635 0.000000 1.215593 0.666667 0.120556 0.026519 0.000000 1.215603 0.688889 0.120557 0.027403 0.000000 1.215614 0.711111 0.120558 0.028287 0.000000 1.215625 0.733333 0.120559 0.029171 0.000000 1.215636 0.755556 0.120560 0.030055 0.000000 1.215647 0.777778 0.120561 0.030939 0.000000 1.215658 0.800000 0.120562 0.031823 0.000000 1.215669 0.822222 0.120563 0.032707 0.000000 1.215679 0.844444 0.120564 0.033592 0.000000 1.215690 0.866667 0.120565 0.034476 0.000000 1.215701 0.888889 0.120566 0.035360 0.000000 1.215712 0.911111 0.120568 0.036244 0.000000 1.215723 0.933333 0.120569 0.037128 0.000000 1.215734 0.955556 0.120570 0.038012 0.000000 1.215744 0.977778 0.120571 0.038897 0.000000 1.215755 1.000000 0.120572 0.039781 0.000000 1.215766 1.022222 0.120573 0.040665 0.000000 1.215777 1.044444 0.120574 0.041549 0.000000 1.215788 1.066667 0.120575 0.042433 0.000000 1.215799 1.088889 0.120576 0.043318 0.000000 1.215810 1.111111 0.120577 0.044202 0.000000 1.215820 1.133333 0.120578 0.045086 0.000000 1.215831 1.155556 0.120579 0.045970 0.000000 1.215842 1.177778 0.120580 0.046855 0.000000 1.215853 1.200000 0.120582 0.047739 0.000000 1.215864 1.222222 0.120583 0.048623 0.000000 1.215875 1.244444 0.120584 0.049507 0.000000 1.215886 1.266667 0.120585 0.050392 0.000000 1.215896 1.288889 0.120586 0.051276 0.000000 1.215907 1.311111 0.120587 0.052160 0.000000 1.215918 1.333333 0.120588 0.053045 0.000000 1.215929 1.355556 0.120589 0.053929 0.000000 1.215940 1.377778 0.120590 0.054813 0.000000 1.215951 1.400000 0.120591 0.055697 0.000000 1.215962 1.422222 0.120592 0.056582 0.000000 1.215972 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 27 1.444444 0.120593 0.057466 0.000000 1.215983 1.466667 0.120594 0.058351 0.000000 1.215994 1.488889 0.120596 0.059235 0.000000 1.216005 1.511111 0.120597 0.060119 0.000000 1.216016 1.533333 0.120598 0.061004 0.000000 1.216027 1.555556 0.120599 0.061888 0.000000 1.216038 1.577778 0.120600 0.062772 0.000000 1.216048 1.600000 0.120601 0.063657 0.000000 1.216059 1.622222 0.120602 0.064541 0.000000 1.216070 1.644444 0.120603 0.065426 0.000000 1.216081 1.666667 0.120604 0.066310 0.000000 1.216092 1.688889 0.120605 0.067195 0.000000 1.216103 1.711111 0.120606 0.068079 0.000000 1.216114 1.733333 0.120607 0.068963 0.000000 1.216124 1.755556 0.120608 0.069848 0.000000 1.216135 1.777778 0.120610 0.070732 0.000000 1.216146 1.800000 0.120611 0.071617 0.000000 1.216157 1.822222 0.120612 0.072501 0.000000 1.216168 1.844444 0.120613 0.073386 0.000000 1.216179 1.866667 0.120614 0.074270 0.000000 1.216190 1.888889 0.120615 0.075155 0.000000 1.216200 1.911111 0.120616 0.076039 0.000000 1.216211 1.933333 0.120617 0.076924 0.000000 1.216222 1.955556 0.120618 0.077808 0.000000 1.216233 1.977778 0.120619 0.078693 0.000000 1.216244 2.000000 0.120620 0.079577 0.000000 1.216255 2.022222 0.120621 0.082258 0.035147 1.216265 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1.2 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1.2 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 1 HYDR RO 1 1 1 WDM 1000 FLOW ENGL REPL RCHRES 1 HYDR O 1 1 1 WDM 1001 FLOW ENGL REPL RCHRES 1 HYDR O 2 1 1 WDM 1002 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1003 STAG ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 17 RCHRES OFLOW OVOL 1 COPY INPUT MEAN END MASS-LINK 17 END MASS-LINK END RUN 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 28 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 29 Predeveloped HSPF Message File 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 30 Mitigated HSPF Message File ERROR/WARNING ID: 341 6 DATE/TIME: 1960/10/23 9:30 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 92 3466.4 3583.2 4087.1 ERROR/WARNING ID: 341 5 DATE/TIME: 1960/10/23 9:30 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 4.3945E-02 1.0508E+04 -5.585E+04 5.3150 5.3149E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1960/10/23 9:45 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 92 3.4664E+03 3583.2 4231.1 ERROR/WARNING ID: 341 5 DATE/TIME: 1960/10/23 9:45 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 4.3945E-02 1.0508E+04 -6.881E+04 6.5481 6.5480 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1960/10/23 10: 0 RCHRES: 1 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 31 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 92 3466.4 3583.2 3747.1 ERROR/WARNING ID: 341 5 DATE/TIME: 1960/10/23 10: 0 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 4.3945E-02 1.0508E+04 -2.526E+04 2.4036 2.4036E+00 2 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 32 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright Â© by : Clear Creek Solutions, Inc. 2005-2020; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com 2020-02-28-WWHM2012_TB Total Area Infil 2/28/2020 2:32:06 PM Page 33 18204 59th Avenue NE REVIEW COMMENT FORM Arlington, WA 98223 360-403-3551 Project Name: Trailer Boss Permit No.: PWD-2024 Review Date: 2-14-2020 Contact: Eric Scott Email: erics@terravistanw.com Review Phase: Civil Report Date: Reviewing Dept.: CED Applicant: Eric Scott DWG Issue Date: # Rev. Dwg. or Addâ€™l Ref. City Comment Response/Resolution Spec. Ref. Approved 1. NEH A Stormwater General Permit is Required The letter from DOE was emailed to CED for inclusion in to the file, on 3/2/2020. 2. NEH A CESCL needs to be specified prior to scheduling the A note specifying the need for a CESCL before pre-construction meeting pre-construction meeting has been added to sheet C1.1 3. NEH Survey Map The three easements on the Survey Map are unclear. The northern electrical easement Specifically the larger easement to the north. Does it (AFN:8001220078) extends from the easement cover the remainder of the property from the line to the boundary shown to the 166th Pl ROW line. The north? Please clarify middle storm drain easement (AFN:8811160334) Extends from the easement line shown to the parcel line. The western 5â€™ electrical easement (AFN:9506090190) runs along the western property line. 4. NEH C1.2 Clarify â€œUnless Notes Otherwiseâ€ as the notes do apply, â€œUnless Notes Otherwiseâ€ has been removed from even if a note says otherwise somewhere. sheet C1.2 5. NEH Provide a temporary construction easement for the south A temporary construction easement has been adjacent property grading provided to CED via email on 3/2/2020. 6. NEH SWPPP Call out protections to prevent over compacting or Callouts have been added to the SWPPP sheet to siltation for the infiltration trenches prevent over-compaction or siltation of infiltration areas. 7. NEH L1.1 Provide shading in the parking area around the office Shade trees have been added around the office 8. NEH Provide the tie-in location of the building downspouts for The downspout tie-in locations have been added to both buildings sheet C2.4 9. NEH C2.4 Provide 20â€™ minimum setback for the infiltration trench All infiltration trenches now have a minimum 20â€™ from the building setback from buildings 10. NEH C2.4 Provide 10â€ minimum setback for the infiltration trenches All infiltration trenches have a minimum 12â€ along the property lines setback from property lines. Note 6 has been added to Sheet C2.4. Page 1 of 2 18204 59th Avenue NE REVIEW COMMENT FORM Arlington, WA 98223 360-403-3551 Project Name: Trailer Boss Permit No.: PWD-2024 Review Date: 2-14-2020 Contact: Eric Scott Email: erics@terravistanw.com Review Phase: Civil Report Date: Reviewing Dept.: CED Applicant: Eric Scott DWG Issue Date: # Rev. Dwg. or Addâ€™l Ref. City Comment Response/Resolution Spec. Ref. Approved 11. NEH Drainage Fill in the numbers and complete the math for the The structure table on sheet C2.4 has been Report structure table slope for the storm perf pipes completed 12. NEH Drainage The Drainage Report must discuss infiltration rate, how it These items have been addressed in the Drainage Report was determined, and the different rates onsite from the Report. All of the facility bottoms are within the testing. Include the depth of the test pit compared to clean sand unit identified by the Geotechnical actual depth of the proposed infiltration bottom. In Report (page 7) as having an infiltration rate of 10 appears 10in/hr was used, but the Geotechnical Report in/hr. recommends 2in/hr for the site (10in/hr is for a very specific region and soil). See page 7 of the Geotechnical Report and be very specific in your report body explaining those recommendations and how your design meets it. 13. NEH Drainage Explain regarding gourndwater elevations compared to With the infiltration trench bottoms at depth of the Report trench bottom elevations. clean sand unit, separation from average groundwater elevation is 2.5â€™. This is explained in the Drainage Report under â€œProposed Conditionsâ€. 14. NEH Drainage Because of the way the WWHM work was done, provide WWHM was used to recalculate the necessary Report listed out a total volume and bottom area needed for the trench length based on the size of the entire site. entire site based on the model. Then provide the The Drainage Information Summary sheet has breakdown for each trench, volume and infiltration area. been updated. Then total together all proposed areas and volumes to show what is actually provided for the site. 15. NEH Drainage Identify and fix any defects in existing sidewalk to be Survey did not note any defects in the sidewalk. Report current with ADA Standards Looking at the crosswalk outside the northwest corner of the site, it appears that the existing curb ramp is substandard. However, it is our understanding that City of Arlington will be repaving Smokey Point Blvd and will be bringing curb ramps up to ADA Standards at that time. 16. NEH Provide Dumpster location A concrete trash enclosure has been added to the plans. Page 2 of 2 18204 59th Avenue NE REVIEW COMMENT FORM Arlington, WA 98223 360-403-3551 Project Name: Trailer Boss Permit No.: PWD-2024 Review Date: 2-14-2020 Contact: Eric Scott Email: erics@terravistanw.com Review Phase: Civil Report Date: Reviewing Dept.: CED Applicant: Eric Scott DWG Issue Date: # Rev. Dwg. or Addâ€™l Ref. City Comment Response/Resolution Spec. Ref. Approved 17. NEH Provide a bike rack, could be placed in the planter strip A bike rack has been added near the office Page 3 of 2 18204 59th Avenue NE REVIEW COMMENT FORM Arlington, WA 98223 360-403-3551 Project Name: Trailer Boss Permit No.: PWD-2024 Review Date: 3-16-2020 Contact: Eric Scott Email: erics@terravistanw.com Review Phase: Civil Report Date: 3/17/2020 Reviewing Dept.: CED Applicant: Eric Scott DWG Issue Date: # Rev. Dwg. or Addâ€™l Ref. City Comment Response/Resolution Spec. Ref. Approved 1. NEH A Stormwater General Permit is Required The letter from DOE was emailed to CED for 3/16/2020 inclusion in to the file, on 3/2/2020. 2. NEH A CESCL needs to be specified prior to scheduling the A note specifying the need for a CESCL before 3/16/2020 pre-construction meeting pre-construction meeting has been added to sheet C1.1 3. NEH Survey Map The three easements on the Survey Map are unclear. The northern electrical easement 3/16/2020 Specifically the larger easement to the north. Does it (AFN:8001220078) extends from the easement cover the remainder of the property from the line to the boundary shown to the 166th Pl ROW line. The north? Please clarify middle storm drain easement (AFN:8811160334) Extends from the easement line shown to the parcel line. The western 5â€™ electrical easement (AFN:9506090190) runs along the western property line. 4. NEH C1.2 Clarify â€œUnless Notes Otherwiseâ€ as the notes do apply, â€œUnless Notes Otherwiseâ€ has been removed from 3/16/2020 even if a note says otherwise somewhere. sheet C1.2 5. NEH Provide a temporary construction easement for the south A temporary construction easement has been adjacent property grading provided to CED via email on 3/2/2020. Please forward sent email to ced@arlingtonwa.gov as we are not showing that we received that email. 6. NEH SWPPP Call out protections to prevent over compacting or Callouts have been added to the SWPPP sheet to 3/16/2020 siltation for the infiltration trenches prevent over-compaction or siltation of infiltration areas. 7. NEH L1.1 Provide shading in the parking area around the office Shade trees have been added around the office 3/16/2020 8. NEH Provide the tie-in location of the building downspouts for The downspout tie-in locations have been added to 3/16/2020 both buildings sheet C2.4 9. NEH C2.4 Provide 20â€™ minimum setback for the infiltration trench All infiltration trenches now have a minimum 20â€™ 3/16/2020 from the building setback from buildings Page 1 of 2 18204 59th Avenue NE REVIEW COMMENT FORM Arlington, WA 98223 360-403-3551 Project Name: Trailer Boss Permit No.: PWD-2024 Review Date: 3-16-2020 Contact: Eric Scott Email: erics@terravistanw.com Review Phase: Civil Report Date: 3/17/2020 Reviewing Dept.: CED Applicant: Eric Scott DWG Issue Date: # Rev. Dwg. or Addâ€™l Ref. City Comment Response/Resolution Spec. Ref. Approved 10. NEH C2.4 Provide 10â€ minimum setback for the infiltration trenches All infiltration trenches have a minimum 12â€ along the property lines setback from property lines. Note 6 has been added to Sheet C2.4. Infiltration must be 10 feet from property line, per city standards, and as discussed multiple times on multiple projects. 11. NEH Drainage Fill in the numbers and complete the math for the The structure table on sheet C2.4 has been 3/16/2020 Report structure table slope for the storm perf pipes completed 12. NEH Drainage The Drainage Report must discuss infiltration rate, how it These items have been addressed in the Drainage Report was determined, and the different rates onsite from the Report. All of the facility bottoms are within the testing. Include the depth of the test pit compared to clean sand unit identified by the Geotechnical actual depth of the proposed infiltration bottom. In Report (page 7) as having an infiltration rate of 10 appears 10in/hr was used, but the Geotechnical Report in/hr. Onsite testing of infiltration systems must be recommends 2in/hr for the site (10in/hr is for a very done during construction to verify infiltration rates specific region and soil). See page 7 of the Geotechnical and appropriate materials. Add note to drawings. Report and be very specific in your report body NO geotechnical information was provided in the explaining those recommendations and how your design area of of the office infiltration system. meets it. 13. NEH Drainage Explain regarding gourndwater elevations compared to With the infiltration trench bottoms at depth of the Report trench bottom elevations. clean sand unit, separation from average groundwater elevation is 2.5â€™. This is explained in the Drainage Report under â€œProposed Conditionsâ€. Report states lowest elevation of trench bottom is 115.5'. The plans do not provide design top and bottom elevations for the infiltration trenches, so based on the top grades on C2.3 and detail 1 on 2.4, the bottom of the trenches are as low as 114.3. And based on Detail 2, they are as low as 112.5. Provide design elevations for the infiltration systems and ensure they are at an elevation appropriate for the groundwater separation. Page 2 of 2 18204 59th Avenue NE REVIEW COMMENT FORM Arlington, WA 98223 360-403-3551 Project Name: Trailer Boss Permit No.: PWD-2024 Review Date: 3-16-2020 Contact: Eric Scott Email: erics@terravistanw.com Review Phase: Civil Report Date: 3/17/2020 Reviewing Dept.: CED Applicant: Eric Scott DWG Issue Date: # Rev. Dwg. or Addâ€™l Ref. City Comment Response/Resolution Spec. Ref. Approved 14. NEH Drainage Because of the way the WWHM work was done, provide WWHM was used to recalculate the necessary Report listed out a total volume and bottom area needed for the trench length based on the size of the entire site. entire site based on the model. Then provide the The Drainage Information Summary sheet has breakdown for each trench, volume and infiltration area. been updated. Then total together all proposed areas and volumes to Summary of areas and volumes requested were not show what is actually provided for the site. provided. 15. NEH Drainage Identify and fix any defects in existing sidewalk to be Survey did not note any defects in the sidewalk. Report current with ADA Standards Looking at the crosswalk outside the northwest corner of the site, it appears that the existing curb ramp is substandard. However, it is our understanding that City of Arlington will be repaving Smokey Point Blvd and will be bringing curb ramps up to ADA Standards at that time. Bring ramps up to ADA standards or provide written variance from PW. (Adjacent and receiving) 16. NEH Provide Dumpster location A concrete trash enclosure has been added to the plans. Trash enclose must be approved per design review. As currently shown on the plans will not be approved with design review. Civil plans cannot be approved without planning approval and design review approval. 17. NEH Provide a bike rack, could be placed in the planter strip A bike rack has been added near the office 3/16/2020 Page 3 of 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/3/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. Per the governorâ€™s order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/6/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. Per the governorâ€™s order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/7/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. Per the governorâ€™s order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/7/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. Per the governorâ€™s order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/9/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. Per the governorâ€™s order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/10/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. Per the governorâ€™s order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/13/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. Per the governorâ€™s COVID-19 order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/14/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. See the really bad photo under the Work Performed section. Per the governorâ€™s COVID-19 order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/15/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. See the photo under the Work Performed section. Per the governorâ€™s COVID-19 order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/16/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. See the photo under the Work Performed section. Per the governorâ€™s COVID-19 order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/17/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. See the photo under the Work Performed section. Per the governorâ€™s COVID-19 order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/20/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. See the photo under the Work Performed section. Per the governorâ€™s COVID-19 order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/21/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. See the photo under the Work Performed section. Per the governorâ€™s COVID-19 order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/22/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. See the photo under the Work Performed section. Per the governorâ€™s COVID-19 order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/23/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. See the photo under the Work Performed section. Per the governorâ€™s COVID-19 order, this is not considered essential construction and the site is currently shut down. Page 2 Department of Community & Economic Development CIVIL INSPECTION DAILY REPORT PROJECT INFORMATION REPORT DATE PROJECT NAME PREPARED BY 4/24/2020 Trailer Boss Brian Grieve WORK PERFORMED Was work performed today? â˜ - Yes â˜’ - No TYPE OF WORK PERFORMED APPROVED APPROVED NOTES PLANS? MATERIALS? N/A TEMPORARY TRAFFIC CONTROL Was Temporary Traffic Control required? â˜ - Yes â˜’ - No Is the contractor maintaining the traffic control devices? â˜ - Yes â˜ - No â˜’ - N/A CLOSURE TYPE APPROVED NOTES PLAN? N/A TEMPORARY EROSION & SEDIMENT CNTROL Are the contractorâ€™s erosion control measures in place? â˜’ - Yes â˜ - No Is the contractor maintaining erosion control BMPs? â˜’ - Yes â˜ - No â˜ - N/A EROSION CONTROL ISSUE NOTES Canâ€™t access site I cannot access the site, but there are no visible erosion issues. INSPECTOR COMMENTS The contractorâ€™s permit has expired. Work cannot resume until the permit has been renewed. The site is locked up and the business is not operating. 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