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Home My WebLink About20250912_PLN1395_Geotech Report CERTERRA Materially Better TM GEOTEST Geotechnical EngineeringReport Holman Recovery Center II Parcel #31052100202000 Arlington , Washington Client Name: Grandview North LLC Project Name: Holman Recovery Center II Project Number: 10-251507-0 Date: June 20, 2025 f CERTERRA Materially BetterT"" f GEOTEST June 20, 2025 Project No. 10-251507-0 Grandview North LLC c/o: Scott Wammack PO Box 159 Arlington, Washington 98223 Regarding: Geotechnical Engineering Report Holman Recovery Center II Parcel #31052100202000 Arlington, Washington Dear Scott: As requested, GeoTest Services, Inc. (Certerra) is pleased to submit the following report summarizing the results of our geotechnical evaluation for the proposed Holman Recovery Center II, located at the above-mentioned parcel number in Arlington,Washington (see Vicinity Map, Figure 1). This report has been prepared in general accordance with the terms and conditions established in our services agreement dated May 14, 2025 and authorized by yourself. We appreciate the opportunity to provide geotechnical services on this project and look forward to assisting you during the construction phase. Should you have any further questions regarding the information contained within the report, or if we may be of service in other regards, please contact the undersigned. Respectfully, Certerra aO A. WAS ., S,r• �� 06 -a� - �,5 Ss�ONA► E� Coire McCabe, L.G. Edwardo Garcia, P.E. Geotechnical Project Manager Geotechnical Department Manager Enclosure: Geotechnical Engineering Report certerra.com 20527 6711 Avenue NE,Arlington,WA 98223 T.360.435.1141 CERTERRA Materially BetterT"" GEOTEST TABLE OF CONTENTS Purpose and Scope of Services...............................................................................................2 ProjectDescription...................................................................................................................2 SiteConditions..........................................................................................................................3 SurfaceConditions ................................................................................................................................3 Subsurface Soil Conditions ..................................................................................................................3 General Geologic Conditions ...............................................................................................................4 Groundwater...........................................................................................................................................4 WebSoil Survey.....................................................................................................................................5 GeologicHazards......................................................................................................................5 SeismicHazard Areas...........................................................................................................................6 Mitigating Liquefaction Induced Settlement ..................................................................................7 Conclusions and Recommendations........................................................................................7 Site Preparation and Earthwork...........................................................................................................8 Filland Compaction...............................................................................................................................8 Reuse of On-Site Soil — Existing Fill................................................................................................8 Reuse of On-Site Soil — Native Soil.................................................................................................8 ImportStructural Fill..........................................................................................................................8 Backfilland Compaction...................................................................................................................9 WetWeather Earthwork........................................................................................................................9 Seismic Design Considerations...........................................................................................................9 FoundationSupport...............................................................................................................................9 AllowableBearing Capacity........................................................................................................... 10 FoundationSettlement................................................................................................................... 10 FloorSupport....................................................................................................................................... 10 Foundation and Site Drainage........................................................................................................... 11 Resistance to Lateral Loads............................................................................................................... 11 Temporary and Permanent Slopes................................................................................................... 12 Utilities .................................................................................................................................................. 13 Pavement Subgrade Preparation...................................................................................................... 13 Light-Duty Flexible Pavement....................................................................................................... 13 Heavy-Duty Flexible Pavement..................................................................................................... 13 ConcretePavement........................................................................................................................ 13 Stormwater Infiltration Potential........................................................................................................ 14 Conceptual Infiltration Results ...................................................................................................... 14 Stormwater Treatment................................................................................................................... 14 Geotechnical Consultation and Construction Monitoring.............................................................. 15 Useof This Report ..................................................................................................................15 References..............................................................................................................................16 certerra.com 20527 6711 Avenue NE,Arlington,WA 98223 f CERTERRA Materially BetterT"" f GEOTEST Purpose and Scope of Services The purpose of this evaluation is to establish general subsurface conditions beneath the site from which conclusions and recommendations pertaining to project design can be formulated. Our scope of services includes the following tasks: • Exploration of soil and groundwater conditions underlying the site by advancing six (6) Test Pit Explorations (TP-1 through TP-6) with a client-provided tracked excavator to evaluate subsurface conditions. • Perform a visual reconnaissance of the proposed development site and immediate vicinity to observe existing site topographic and geologic conditions. • Laboratory testing on representative samples to classify and evaluate the engineering characteristics of the soils encountered. • Provide a preliminary assessment of the on-site infiltration capability based on USDA textural classification per the Stormwater Management Manual for Western Washington[Manual]as adopted by the City of Arlington. • Provide a written report containing a description of surface and subsurface conditions and exploration logs. Included are findings and recommendations pertaining to site preparation and earthwork, including stripping depths, subgrade preparation below the planned buildings, reuse of on-site soils, wet weather earthwork, and criteria for selection, placement, and compaction of Structural Fill. • Provide recommendations for foundation support of the planned structures including allowable bearing pressures, bearing elevations, frost penetration depth, a discussion of potential foundation settlement (total and differential), floor support, and general foundation design. • Provide recommendations for lateral earth pressures including active and at-rest conditions, allowable passive soil resistance, groundwater considerations, drainage recommendations, temporary and permanent slope inclinations, and utilities. • A discussion of the Seismic Site Class considerations based on the 2021 International Building Code (IBC). • Provide an assessment of geologically hazardous areas per the City of Arlington Municipal Code (AMC) and provided mitigation recommendations for geologically hazardous areas (if present). • Provide recommendations for geotechnical monitoring, materials testing, and consultation during construction. Project Description We understand that there are plans to construct a new single-story complex that will be used for recovery and substance abuse treatment. Structural plans were not available at the time of this report, but construction is expected to utilize wood- or steel-frame construction with shallow conventional foundations and slab-on-grade floors. Due to the nature of the facility, it is feasible that masonry or reinforced wall systems could be utilized, but structural loads for the facility are expected to be generally light. The facility will have paved parking, asphalt drive paths, and concrete sidewalks/hardscapes. Certerra does not expect that significant grading will be required to achieve final site grades. A stormwater plan was not available at the time of this report. The infiltration of stormwater is desired as a project goal and preliminary infiltration feasibility information is outlined later in this report. certerra.com 20527 67"Avenue NE,Arlington,WA 98223 2 f CERTERRA Materially BetterT" f GEOTEST Site Conditions This section includes a description of the general surface and subsurface conditions observed at the project site during the time of our field investigation. Interpretations of site conditions are based on the results and review of available information, site reconnaissance, subsurface explorations, laboratory testing, and previous experience in the project vicinity. Surface Conditions The project area is located in the southern portion of the parcel (No. 31052100202000), located near 4228 Airport Boulevard in Arlington, Washington. The project area is currently undeveloped outside of North County Fire Station #48. The site is accessed by 43rd Avenue NE off Airport Boulevard. The proposed area of improvement is generally flat with less than a few feet of elevation differential across the site and is covered in manicured grass. The Arlington airport is to the east of the property, while residential housing borders the western property boundary. r S� u s1 s Images 1 (left)and 2(right):The typical site conditions prior to our explorations,showing the site is flat and covered in landscaped grasses and proximity of the fire station (Image 1 -facing north and Image 2—facing south). Images 1 through 4 were taken during our May 28, 2025 site visit. Subsurface Soil Conditions Subsurface conditions were explored and documented by advancing six test pits (TP-1 through TP-6) on May 28, 2025, under the direction of a Geotechnical Technician. Soils were classified in general accordance with the guidelines of the American Society for Testing and Materials (ASTM) D2487 and D2488. Approximate locations of these explorations have been plotted on the Site and Exploration Plan (Figure 2). A Soil Classification System and Key can be found as Figure 4, detailed test pit logs are presented as Figures 5 through 7, with laboratory results as Figures 8 and 9. Test pit explorations consisted of the excavation of shallow open pits with the use of a rubber tracked mini excavator and operator provided by the Client. Select grab samples were obtained at approximately 2-foot intervals or upon changes in soil stratigraphy. Depths of the test pit explorations ranged from approximately 8 to 9 feet below the ground surface (BGS). In all explorations, Certerra observed approximately 0.5 feet of topsoil consisting of loose, dark brown,damp, silty sand with numerous organics (grasses, roots, weeds, etc.). In TP-4 to TP-6, Certerra observed uncontrolled fill under the topsoil to a depth of 1 to 2 feet BGS. The uncontrolled fill consisted of medium dense to dense, dark brown, damp, gravelly, silty sand to slightly silty, very sandy gravel with varying amounts of organic materials. Underlying the topsoil and fill (when observed) was 1 to 2.5 feet of medium dense, orange-brown, damp, silty sand with variable gravel content and occasional organics, interpreted to be weathered Marysville Sand. Below the weathered Marysville Sand, we observed medium dense, gray-brown, damp, sand with variable, but generally low amounts, of silt and certerra.com 20527 67"Avenue NE,Arlington,WA 98223 3 f CERTERRA Materially BetterT" f GEOTEST gravel that was interpreted to be non-weathered Marysville Sand. The non-weathered Marysville Sand deposits were observed to the terminal depth of all test pits. C 3�R - Y, M. y+j W.-'�Ste. •-''+-ii. _ j '4s - • y.- s is "; #: Images 3(left)and 4(right): Digging conditions and location of TP-4 (Image 3), and typical soil conditions observed on site consisting of weathered and non-weathered Marysville Sand (Image 4). General Geologic Conditions Geologic information for the project site was obtained from the Geologic map of the Arlington West 7.5-minute quadrangle, Snohomish County, Washington (Minard, J.P., 1985) published by the U.S. Geological Survey. According to the referenced map,subsurface soils in the vicinity of the project site consist of Marysville Sand Member(Qvrm)of the regional Recessional Glacial Outwash deposit(Qvr).These materials were deposited by stagnating and receding Vashon Glacier during the Fraser Glaciation. The Marysville Sand Member generally consists of well-drained, stratified to massive, outwash sand with some pebble gravel with localized areas of silt and clay. The member ranges in depth from about 1 meter to possibly more than 30 meters in some portions of its mapped extent. Native soils encountered during our subsurface explorations were generally consistent with the mapped Marysville Sand deposits. A review of the Washington State Department of Natural Resources (DNR) Geologic Information Portal indicates that no known landslides are mapped within the immediate site vicinity. However, according to the same resource, the Devil's Mountain Fault Zone (DMFZ) system is located roughly 13.5 miles north of the project site. The DMFZ is an east-west trending, left-lateral oblique slip fault system that has been active as recently as 100 to 500 years ago and has the potential to produce a magnitude 7.5 earthquake or greater(Barrie, 2017). Groundwater Groundwater was not encountered during our explorations in May 2025. However, a review of the Washington State Department of Ecology Well Log Viewer webpage indicates that wells in the vicinity of the subject area reported static water levels at depths of about 27 feet BGS at the time of well construction and on the property where the well was constructed. certerra.com 20527 67"Avenue NE,Arlington,WA 98223 4 f CERTERRA Materially BetterT" f GEOTEST Certerra also has local experience that suggest that the groundwater table is present below depths of about 20 feet BGS in the vicinity. We expect that the groundwater encountered at those depths is reflective of the regional groundwater table elevation. The groundwater conditions reported on the exploration logs are for the specific locations and dates indicated and therefore may not be indicative of other locations and/or times. Groundwater levels are variable and groundwater conditions will fluctuate depending on local subsurface conditions, precipitation, and changes in on-site and offsite use. Web Soil Survey According to the United States Department of Agriculture(USDA) Natural Resource Conservation Service(NRCS) Web Soil Survey website, one relevant soil unit is present on the subject property, Lynnwood loamy sand, 0 to 3 percent slopes. Please refer to Table 1 below for general characteristics of the mapped site soils. Based on their erosion "K"factor assigned by the NRCS,the soils present on-site are considered to have a moderate susceptibility to erosion.The value of the erosion factor "K" ranges from 0.02 to 0.69; the higher the value, the more susceptible the soil is to sheet and rill erosion by water. Mapped site soils are generally consistent with the soils observed during our explorations. The site soils have a Land Capability Classifications "s". Soils classified as "s"are made up of soils that have such limitations as shallowness of rooting zones, stones, low moisture-holding capacity, low fertility difficult to correct, and salinity or sodium (USDA, 1961). The soils found within the project vicinity are considered to have a low to high susceptibility to erosion based on their K Factor ratings. However, the soil's vulnerability to sheet and rill erosion are considered low based on the lack of slopes and vegetation that is present within the proposed area of development. In our opinion, erosion may be managed during and following construction using conventional best management practices. SymbolTable 1 - USDA NRCS Soil Classifications Map Unit i Map Unit Name Lynnwood loamy sand,0 to 3 percent slopes Soil Description Loamy sand to sand Landform Terraces, outwash plains Parent Material Glacial outwash Land Capability Classification 4s Erosion K Factor,Whole Soil 0.20 Geologic Hazards Based on Arlington Municipal Code (AMC) 20.93.600, Geologic Hazard Areas mean "areas susceptible to erosion, sliding, earthquakes, liquefaction, or other geological events." Geologically hazardous areas shall be classified based upon the history or existence of landslides, unstable soils, steep slopes, high erosion potential or seismic hazards. In determining the significance of a geologically hazardous area the following criteria shall be used: (1) Potential economic, health, safety, and environmental impact related to construction in the area; (2) Soil type, slope, vegetative cover, and climate of the area; certerra.com 20527 67"Avenue NE,Arlington,WA 98223 5 f CERTERRA Materially BetterT"" f GEOTEST (3) Available documentation of history of soil movement, the presence of mass wastage, debris flow, rapid stream incision,stream bank erosion or undercutting by wave action,or the presence of an alluvial fan which may be subject to inundation, debris flows, or deposition of stream-transported sediments. The following sections provide a discussion of the Geologic Hazard Areas that we observed on or in the vicinity of the subject property. After careful review of publicly available geologic literature pertaining to the area, it should be noted that geologic hazards associated with "other geologic events" such as erosion hazards, landslide hazards, volcanic eruptions, tsunami events, etc., were not found to be applicable to this project due to the location of the proposed development. Seismic Hazard Areas The site is underlain by loose to medium-dense Marysville Sand with interbeds of denser Marysville Sand.At the time of our recent subsurface explorations, groundwater was not encountered in May 2025 which is considered the "dry season." According to the Geologic Information Portal, the subject property is mapped as having a low to moderate potential for seismic liquefaction and the project site does not exist near any active faults or folds. However, this map only provides an estimate of the likelihood that soil will liquefy as a result of earthquake shaking and is meant as a general guide to delineate areas prone to liquefaction. Based on the existing site conditions, proposed construction, as well as our local experience in the area, it is Certerra's opinion that there is a low to moderate risk of liquefaction occurring beneath the subject site during a design level earthquake. 204th St NE PoWtoge Creak co 2ufnh St Nr Proiect Site F-1 Image 5:Screenshot from the DNR Geologic Information Portal,in which the entire project site is considered to possess a low to moderate liquefaction susceptibly(yellow). The Pacific Northwest is seismically active. Large Cascadia subduction zone earthquakes with possible magnitudes of 8 or 9 could produce ground shaking events with the potential to significantly impact the subject property. Cascadia subduction zone earthquakes have occurred 6 times in the last 3,500 years with the most recent taking place in 1700, approximately 325 years ago. They have been determined to have an average reoccurrence interval of approximately 300 to 700 years (Atwater and Haley, 1997). certerra.com 20527 67"Avenue NE,Arlington,WA 98223 6 f CERTERRA Materially BetterT" f GEOTEST Mitigating Liquefaction Induced Settlement Certerra recommends that the building foundations implement interconnected grade beams or structural slab floors to mitigate differential settlement due to the liquefaction potential that exists on this property. Grade beam reinforcement or structural slab floors will not prevent total building settlement but will encourage the building to settle as a unit,thus reducing structural damage incurred due to differential settlement. It must be understood that these mitigations will not address total settlements but will help reduce differential settlement across the building footprint and address life-safety concerns during a design seismic event. As such, the Owner must accept the risk of total settlement that may occur during a seismic event if ground improvements or deep foundation systems are not incorporated into the plan for site development. It is our understanding that deep foundation systems and ground improvement methods are not currently being considered for the project. If, however, deep foundation systems or ground improvement approaches are preferred by the project ownership, Certerra would be pleased to provide updated recommendations to facilitate the design of such a system. Conclusions and Recommendations Based on the evaluation of the data collected during this investigation, it is our opinion that the subsurface conditions at the site are suitable for the proposed development, provided the recommendations contained herein are incorporated into the project design. The site is relatively flat and is underlain by approximately 0.5 feet of topsoil consisting of loose, dark brown,damp, silty sand with numerous organics. At the TP-4 through TP-6 exploration locations, Certerra observed the presence of uncontrolled fill to depths of up to 1 to 2 feet BGS.The uncontrolled fill consisted of medium dense to dense, dark brown, gravelly, silty sand to slightly silty, very sandy gravel with variable amounts of organics. Underlying the topsoil and, where encountered, the uncontrolled fill, Certerra observed loose to medium dense, native soil which Certerra interpreted to be representative of Marysville Sand. When encountered and generally on the eastern/northeastern of the project site, uncontrolled fill, deleterious materials, organic debris, and loose/unsuitable portions of native soil (which cannot be readily recompacted) should be removed from below the building footprint and replaced with suitable Structural Fill. We recommend the Client plan for typical stripping depths below the building footprint of approximately 1 to 2 feet in the proposed location of development. Fill thicknesses may vary across the site and may require more than the 1 to 2 feet of overexcavation. Please note that foundations will need to be 1.5 feet below finished grades for freeze/thaw protection, so 1 to 2 feet of stripping below foundations may expose native soils. In all cases the Geotechnical Engineer or their representative should view the prepared subgrade areas. Leaving uncontrolled fill in place and below pavement sections does present risk of long-term settlement and/or increased maintenance, but this risk may be preferred to the costs associated with a full removal and replacement with Structural Fill materials. In parking and drive path areas, Certerra recommends no more than 2 feet of stripping and remedial compaction of exposed mineral soil to a firm and unyielding condition prior to replacement with Structural Fill and road base materials. Highly organic soil should, however, be removed to expose mineral soil. Based on our explorations, the site is considered to present a low to moderate potential for liquefaction induced settlement during a design level seismic event.As such,we recommend that the project incorporates mitigation to address this potential hazard. Differential settlement due to liquefaction can be reduced through the incorporation of interconnected grade beams (or structural slabs) into the foundation design. Please note that grade beams and/or structural slabs will not prevent the settlement of the building due to liquefaction occurring on the project site. Post-construction settlements due to liquefaction can only be prevented through the use of a deep foundation system and/or ground improvements. Certerra is currently assessing the infiltration potential for this project site by providing preliminary rates based on the Grain Size Method outlined in the Manual. certerra.com 20527 67"Avenue NE,Arlington,WA 98223 7 f CERTERRA Materially BetterT" f GEOTEST Site Preparation and Earthwork The portions of the site proposed for foundation(s),floor slabs, pavement, and/or sidewalk development should be prepared by removing existing pavements, topsoil, deleterious material, and significant accumulations of organics. Based on our explorations, Certerra anticipates at least 1 to 2 feet of removal at most locations to expose native soils. Uncontrolled fill soil exists across portions of the area of the site planned for development and is likely variable in thickness in the proposed building locations. Finished site grades have not been established, so it is currently unknown if the project will be graded or what finished building elevations will be. Prior to placement of any foundation elements or Structural Fill, the exposed subgrade under all areas to be occupied by soil-supported floor slabs, spread, or continuous foundations should be recompacted to a firm and unyielding condition. Verification of compaction can be accomplished through proof rolling with a loaded dump truck, large self-propelled vibrating roller, or similar piece of equipment applicable to the size of the excavation. The purpose of this effort is to identify loose or soft soil deposits so that, if feasible,the soil distributed during site work can be recompacted. Proof rolling should be carefully observed by qualified geotechnical personnel. Areas exhibiting significant deflection, pumping, or over-saturation that cannot be readily compacted should be overexcavated to firm soil. Alternatively, Dynamic Cone Penetrometers or soil probing by a qualified Certerra representative can confirm firm and unyielding conditions if a proof roll cannot be performed. Overexcavated areas should be backfilled with compacted granular material placed in accordance with subsequent recommendations for Structural Fill. During periods of wet weather, proof rolling could damage the exposed subgrade. Under these conditions, qualified geotechnical personnel should observe subgrade conditions to determine if proof rolling is feasible. Fill and Compaction Structural Fill used to obtain final elevations for footings and soil-supported floor slabs must be properly placed and compacted. In most cases, suitable, non-organic, predominantly granular soil may be used for fill material provided the material is properly moisture conditioned prior to placement and compaction, and the specified degree of compaction is obtained. Material containing topsoil, wood, trash, organic material, or construction debris is not suitable for reuse as Structural Fill and should be properly disposed offsite or placed in non-structural areas. Soils containing more than approximately 5 percent fines are considered moisture sensitive and are difficult to compact to a firm and unyielding condition when over the optimum moisture content by more than approximately 2 percent. The optimum moisture content is that which allows the greatest dry density to be achieved at a given level of compactive effort. Reuse of On-Site Soil—Existing Fill Existing fill soils were observed to extend to approximately 1 to 2 feet BGS in our explorations.The existing fill soils contained variable amounts of organics. Fill containing refuse, debris, or organics should be segregated and removed from the site. It should be noted that the existing fill also contained elevated fines content and are considered moisture sensitive. As such, we do not recommend reuse of these soils in structural areas. Reuse of On-Site Soil—Native Soil The native,granular Marysville Sand is suitable for reuse as Structural Fill when placed at or near optimum moisture contents, as determined by ASTM D1557 and if allowed for in the project plans and specifications. Using Marysville Sand during wet weather construction periods should be expected to be challenging due to the variable silt contents in the soil. We recommend that native soils not properly moisture conditioned, and/or any onsite soil containing significant organic content be limited to non-structural areas or be disposed of offsite. Import Structural Fill Certerra recommends that imported Structural Fill consist of clean, well-graded sandy gravel, gravelly sand, or other approved naturally occurring granular material (pit run)with at least 30 percent retained on the No.4 sieve, or a well-graded crushed rock. Structural Fill for dry weather construction may contain up to 10 percent fines (that portion passing the U.S. No. 200 sieve) based on the portion passing the U.S. No. 4 sieve. The use of an imported fill having more than 10 percent certerra.com 20527 67"Avenue NE,Arlington,WA 98223 8 f CERTERRA Materially BetterT" f GEOTEST fines may be feasible, but the use of these soils should generally be reviewed by the design team prior to the start of construction. Imported Structural Fill with less than 5 percent fines should be used during wet weather conditions. Due to wet site conditions, soil moisture contents could be high enough that it may be difficult to compact even clean imported select granular fill to a firm and unyielding condition. Soils with an over-optimum moisture content should be scarified and dried back to a suitable moisture content during periods of dry weather or removed and replaced with drier Structural Fill. Backfill and Compaction Structural Fill should be placed in horizontal lifts. The Structural Fill must measure 8 to 10 inches in loose thickness and be thoroughly compacted.All Structural Fill placed under load bearing areas should be compacted to at least 95 percent of the maximum dry density,as determined using test method ASTM D1557.The top of the compacted Structural Fill should extend outside all foundations and other structural improvements a minimum distance equal to the thickness of the fill. We recommend that compaction be tested after placement of each lift in the fill pad. Wet Weather Earthwork Fine grained uncontrolled fill and native soils are particularly susceptible to degradation during wet weather due to the presence of fines within the site soils. As a result, it may be difficult to control the moisture content of site soils during the wet season. If construction takes place during wet weather, Certerra recommends that Structural Fill consist of imported, clean,well-graded sand or sand and gravel as described above. If fill is to be placed or earthwork is to be performed in wet conditions, the contractor may reduce soil disturbance by: • Limiting the size of areas that are stripped of topsoil and left exposed • Accomplishing earthwork in small sections • Limiting construction traffic over unprotected soil • Sloping excavated surfaces to promote runoff • Limiting the size and type of construction equipment used • Providing gravel `working mats' over areas of prepared subgrade • Removing wet surficial soil prior to commencing fill placement each day • Sealing the exposed ground surface by rolling with a smooth drum compactor or rubber-tired roller at the end of each working day • Providing up-gradient perimeter ditches or low earthen berms and using temporary sumps to collect runoff and prevent water from ponding and damaging exposed subgrades Seismic Design Considerations The Pacific Northwest is seismically active, and the site could be subject to movement from a moderate or major earthquake. Consequently, moderate levels of seismic shaking should be accounted for during the design life of the project, and the proposed structure should be designed to resist earthquake loading using appropriate design methodology. For structures designed using the seismic design provisions of the 2021 International Building Code, the native Marysville Sand Deposits underlying the site are classified as Site Class D-E according to ASCE 7-22. The Structural Engineer should select the appropriate design response spectrum based on Site Class D-E soil and the geographical location of the proposed construction. Foundation Support Certerra recommends that existing topsoil, uncontrolled fill materials and loose, upper portions of the native soil be removed from beneath the building foundation area(s)to expose medium dense Maryville Sand soils.Certerra identified approximately 1 to 2 feet of fill consisting of dense, gravelly silty sand with some organics overlying weathered and non-weathered Marysville Sand soils. Certerra does not recommend that new foundations be placed on existing uncontrolled fill. In all cases, new foundations must be placed on either firm and unyielding native soil or Structural Fill overlying firm and unyielding native soil. certerra.com 20527 67"Avenue NE,Arlington,WA 98223 9 f CERTERRA Materially BetterT"" f GEOTEST Continuous and isolated spread footings should be founded 18 inches (at minimum) below the lowest adjacent final grade for freeze/thaw protection. The footings should be sized in accordance with the Structural Engineer's prescribed design criteria and seismic considerations. Certerra recommends that mitigation for differential settlement due to liquefaction consist of a structural slab or interconnected grade beam foundation.The intent of the structural slab and/or grade beam foundation is to have the building settle as a unit and limit the amount of differential settlement that occurs across the building footprint.The use of a structural slab and/or grade beams requires that the Owner accept the risk of future settlement under the structure during a design seismic event.There should not be an expectation that structural slabs will prevent settlement that can occur during a design seismic event. The thickened edge of a structural slab and/or grade beams is expected to be similar in width to a conventional foundation system and should distribute structural loads in a similar fashion. To address freeze/thaw protection concerns, Certerra recommends that the thickened edge of structural slabs be founded at least 18 inches below the lowest adjacent final grade. Similarly, conventional foundations with interconnected grade beams should be founded at least 18 inches below the lowest adjacent final grade. Allowable Bearing Capacity Based on the soil conditions encountered during our field exploration program, and assuming the above foundation support criteria are satisfied, prepared subgrade soil should be suitable to support a net allowable bearing pressure of 2,000 pounds per square foot (psf) for the thickened edge portion of structural slabs. Please note that the thickened edge portion of the structural slab is assumed to be constructed and to function similar to a conventional foundation system,which is why it can be proportioned for the referenced bearing pressure. For the interior portions of the structural slab, Certerra assumes a total distributed load of no more than 500 psf across the remainder of the structural slab footprint. Conventional foundations with interconnected grade beams may be designed to support a net allowable bearing pressure of 2,000 psf. The term "net allowable bearing pressure" refers to the pressure that can be imposed on the soil at foundation level resulting from the total of all dead plus live loads, exclusive of the weight of the footing or any backfill placed above the footing. Foundation Settlement Mat slab systems and/or interconnected grade beams can be expected to have less than 1 inch of settlement under static conditions. During seismic conditions, however, the liquefaction-induced settlements across the building footprint could be more than 2 inches. The settlement of shallow foundations depends on foundation size and bearing pressure, as well as the strength and compressibility characteristics of the underlying soil. Differential settlement between two adjacent load-bearing components supported on competent soil is estimated to be less than one half the total settlement. Due to the liquefaction potential that exists on this site, the Owner should expect additional settlements during a seismic event, although the use of structural slabs and interconnected grade beams are intended to reduce the amount of differential settlement that can occur across the building footprint, thus addressing life/safety concerns. Floor Support Conventional slab-on-grade floor construction is feasible for the planned site improvements. Floor slabs may be supported on properly prepared native subgrade or on properly placed and compacted Structural Fill placed over properly prepared native soil. Prior to placement of the Structural Fill, the native soil should be proof-rolled as recommended in the Site Preparation and Earthwork section of this report. Certerra recommends that interior concrete slab-on-grade floors be underlain with at least 6 inches of clean, compacted, free-draining gravel.The gravel should contain less than 3 percent passing the U.S. Standard No. 200 sieve(based on a wet sieve analysis of that portion passing the U.S. Standard No. 4 sieve). The purpose of this gravel layer is to provide uniform support for the slab, provide a capillary break, and act as a drainage layer. To help reduce the potential for water vapor migration through floor slabs, a continuous 10-mil minimum thick polyethylene sheet with tape-sealed joints should be certerra.com 20527 67"Avenue NE,Arlington,WA 98223 10 f CERTERRA Materially BetterT" f GEOTEST installed below the slab to serve as an impermeable vapor barrier. The vapor barrier should be installed and sealed in accordance with the manufacturer's instructions. The American Concrete Institute (ACI) guidelines suggest that the slab may either be poured directly on the vapor barrier or on a granular curing layer placed over the vapor barrier depending on construction conditions. Certerra recommends that the Architect or Structural Engineer specify if a curing layer should be used. If moisture control within the building is critical, we recommend a representative of Certerra observe the vapor barrier to confirm that joints and penetrations have been properly sealed. Exterior concrete slabs-on-grade, such as sidewalks, may be supported directly on undisturbed native soil or on properly placed and compacted Structural Fill; however, long-term performance will be enhanced if exterior slabs are placed on a layer of clean, durable, well-draining granular material. Foundation and Site Drainage Positive surface gradients should be provided adjacent to the proposed building to direct surface water away from the building and toward suitable drainage facilities. Roof drainage should not be introduced into the perimeter footing drains but should be separately discharged directly to the stormwater collection system or similar municipality-approved outlet. Pavement and sidewalk areas, if present, should be sloped and drainage gradients should be maintained to carry surface water away from the building towards an approved stormwater collection system. Surface water should not be allowed to pond and soak into the ground surface near buildings or paved areas during or after construction. Construction excavations should be sloped to drain to sumps where water from seepage, rainfall,and runoff can be collected and pumped to a suitable discharge facility. To reduce the potential for groundwater and surface water to seep into interior spaces, Certerra recommends that an exterior footing drain system be constructed around the perimeter of new building foundations as shown in the Conceptual Footing and Wall Drain Section (Figure 3)of this report.The drain should consist of a perforated pipe measuring 4 inches in diameter at minimum, surrounded by at least 12 inches of filtering media. The pipe should be sloped to carry water to an approved collection system. The filtering media may consist of open-graded drain rock wrapped in a nonwoven geotextile fabric such as Mirafi 140N (or equivalent) or wrapped with a graded sand and gravel filter. For foundations supporting retaining walls, drainage backfill should be carried up the back of the wall and be at least 12 inches wide. The drainage backfill should extend from the foundation drain to within approximately 1 foot of the finished grade and consist of open-graded drain rock containing less than 3 percent fines by weight passing the U.S.Standard No.200 sieve(based on a wet sieve analysis of that portion passing the U.S. Standard No. 4 sieve). The invert of the footing drainpipe should be placed at approximately the same elevation as the bottom of the footing or 12 inches below the adjacent floor slab grade, whichever is deeper, so that water will be contained.This process prevents water from seeping through walls or floor slabs. The drain system should include cleanouts to allow for periodic maintenance and inspection. Please understand that the above recommendations are intended to assist the Design engineer and/or Architect in development of foundation and site drainage parameters and are based on our experience with similar projects in the area. The final foundation and site drainage plan that will be incorporated into the project plans is to be determined by the design team. Resistance to Lateral Loads The lateral earth pressures that develop against retaining walls will depend on the method of backfill placement, degree of compaction, slope of backfill, type of backfill material, provisions for drainage, magnitude and location of any adjacent surcharge loads,and the degree to which the wall can yield laterally during or after placement of backfill. If the wall is allowed to rotate or yield so the top of the wall moves an amount equal to or greater than about 0.001 to 0.002 times its height (a yielding wall), the soil pressure exerted comprises the active soil pressure. When a wall is restrained against lateral movement or tilting (a nonyielding wall), the soil pressure exerted comprises the at rest soil pressure. Wall restraint may develop if a rigid structural network is constructed prior to backfilling or if the wall is inherently stiff. certerra.com 20527 67"Avenue NE,Arlington,WA 98223 11 f CERTERRA Materially BetterT" f GEOTEST Certerra recommends that yielding walls under drained conditions be designed for an equivalent fluid density of 35 pounds per cubic ft (pcf), for granular, imported Structural Fill and 40 pcf for native soils in active soil conditions. Nonyielding walls under drained conditions should be designed for an equivalent fluid density of 55 pcf,for Structural Fill and 60 pcf for native soils in at-rest conditions. Design of walls should include appropriate lateral pressures caused by surcharge loads located within a horizontal distance equal to or less than the height of the wall. For uniform surcharge pressures, a uniformly distributed lateral pressure equal to 35 percent and 50 percent of the vertical surcharge pressure should be added to the lateral soil pressures for yielding and nonyielding walls, respectively. Certerra also recommends that a seismic surcharge of 8*H psf be included where H is the wall height. The seismic surcharge should be modeled as a rectangular distribution with the resultant applied at the midpoint of the wall. Passive earth pressures developed against the sides of building foundations, in conjunction with friction developed between the base of the footings and the supporting subgrade,will resist lateral loads transmitted from the structure to its foundation. For design purposes,the passive resistance of well-compacted fill placed against the sides of foundations is equivalent to a fluid with a density of 300 pcf.The recommended value includes a safety factor of about 1.5 and is based on the assumption that the ground surface adjacent to the structure is level in the direction of movement for a distance equal to or greater than twice the embedment depth. The recommended value also assumes drained conditions that will prevent the buildup of hydrostatic pressure in the compacted fill. Retaining walls should include a drain system constructed in general accordance with the recommendations presented in the Foundation and Site Drainage section of this report. In design computations, the upper 12 inches of passive resistance should be neglected if the soil is not covered by floor slabs or pavement. If future plans call for the removal of the soil providing resistance,the passive resistance should not be considered. An allowable coefficient of base friction of 0.35, applied to vertical dead loads only, may be used between the underlying imported granular Structural Fill and the base of the footing. If passive and frictional resistance are considered together, one half the recommended passive soil resistance value should be used since larger strains are required to mobilize the passive soil resistance as compared to frictional resistance. A safety factor of about 1.5 is included in the base friction design value. Certerra does not recommend increasing the coefficient of friction to resist seismic or wind loads. Temporary and Permanent Slopes The contractor is responsible for construction slope configurations and maintaining safe working conditions, including temporary excavation stability. All applicable local, state, and federal safety codes should be followed. All open cuts should be monitored during and after excavation for any evidence of instability. If instability is detected,the contractor should flatten the side slopes or install temporary shoring. Temporary excavations in excess of 4 feet should be shored or sloped in accordance with Safety Standards for Construction Work Part N, WAC 296-155-66403. Marysville Sand Deposits are classified as Type C soils. According to WAC 296-155-66401, Type C soils may be sloped as steep as 1.5H:1V (Horizontal: Vertical). All soils encountered are classified as Type C soil in the presence of groundwater seepage. Type C soils may be sloped as steep as 1.5H:1V. Flatter slopes or temporary shoring may be required in areas where groundwater flow is present and unstable conditions develop. Temporary slopes and excavations should be protected as soon as possible using appropriate methods to prevent erosion from occurring during periods of wet weather. Certerra recommends that permanent cut or fill slopes be designed for inclinations of 2H:1V or flatter. Permanent cuts or fills used in detention ponds, retention ponds,or earth slopes intended to hold water should be 3H:1 V or flatter.All permanent slopes should be vegetated or otherwise protected to limit the potential for erosion as soon as practical after construction. Certerra recommends that the Civil designer take into account the site's proximity to the airport. Open ponds my present challenges and/or may not be allowed by governing jurisdictions due to the potential for increased bird strikes. Stormwater Management plans must consider or account for the nearby airport. certerra.com 20527 67"Avenue NE,Arlington,WA 98223 12 f CERTERRA Materially BetterT"" f GEOTEST Utilities Utility trenches must be properly backfilled and compacted to reduce cracking or localized loss of foundation, slab, or pavement support. Excavations for new shallow underground utilities are expected to be placed within native soils. Trench backfill in improved areas(beneath structures, pavements,sidewalks,etc.)should consist of Structural Fill as defined in the Fill and Compaction section of this report. Outside of improved areas, trench backfill may consist of reused material provided the backfill can be compacted to the project specifications. Trench backfill should be placed and compacted in general accordance with the recommendations presented in the Fill and Compaction section of this report. Surcharge loads on trench support systems due to construction equipment, stockpiled material, and vehicle traffic should be included in the design of any anticipated shoring system. The contractor should implement measures to prevent surface water runoff from entering trenches and excavations. In addition, vibration as a result of construction activity and traffic may cause caving of the trench walls. The contractor is responsible for trench configurations. All applicable local, state, and federal safety codes should be followed. All open cuts should be monitored by the contractor during excavation for any evidence of instability. If instability is detected,the contractor should flatten the side slopes or install temporary shoring. If groundwater or groundwater seepage is present, and the trench is not properly dewatered, the soil within the trench zone may be prone to caving, channelling, and running. Trench widths may be substantially wider than under dewatered conditions. Pavement Subgrade Preparation Selection of a pavement section is typically a choice relative to a higher initial cost and lower long-term maintenance, or a lower initial cost with more frequent maintenance. For this reason, we recommend that the Owner participates in the selection of the proposed pavement sections planned for the site. Site grading plans should include provisions for sloping of the subgrade soils in proposed pavement areas, so that passive drainage of the pavement section(s) can proceed uninterrupted during the life of the project. The proposed pavement areas should be prepared as indicated in the Site Preparation and Earthwork section of this report. We provide further detail for suitable subgrade preparation in the Foundation Support and Slab on Grade support sections of this report. Light-Duty Flexible Pavement Certerra anticipates that asphalt pavement will be used for new passenger vehicle access drives and parking areas. We recommend that a standard, or`light duty,' pavement section consist of 2.5 inches of 1/2-inch HMA asphalt above 6 inches of crushed surfacing base course (CSBC) meeting criteria set forth in the Washington State Department of Transportation (WSDOT) Standard Specification 9-03.9[3] Crushed Surfacing Base Course. Certerra is available to further consult, review, and/or modify our pavement section recommendations based on further discussion and/or analysis with the project team/owner.The above pavement sections are initial recommendations and may be accepted and/or modified by the site Civil Engineer based on the actual finished site grading elevations and/or the owner's preferences. Heavy-Duty Flexible Pavement The drive-thru lane and/or areas that will be accessed by more heavily loaded vehicles,emergency access vehicles,garbage trucks, and similar vehicles will require a thicker asphalt section and should be designed using a paving section consisting of 3 inches of Class 1/2-inch HMA asphalt surfacing above 6 inches of CSBC meeting criteria set forth in WSDOT Standard Specification 9-03.9[3]. Concrete Pavement Concrete pavements could be used for access and drive areas. Design of concrete pavements is a function of concrete strength, reinforcement steel, and the anticipated loading conditions for the roads. For design purposes, a vertical modulus of subgrade reaction of 200 pounds per cubic inch(pci)should be expected for concrete roadways constructed over properly placed and compacted Structural Fill. Certerra expects that concrete pavement sections, if utilized, will be at least 6 inches thick and be founded on a minimum of 6 inches of compacted CSBC. The design of concrete pavements will need to be certerra.com 20527 67"Avenue NE,Arlington,WA 98223 13 f CERTERRA Materially BetterT"" f GEOTEST performed by a Structural Engineer. Certerra recommends that subgrade soils supporting concrete pavement sections include minor grade changes to allow for passive drainage away from the pavement. Certerra is available to further consult, review, and/or modify our pavement section recommendations based on further discussion and/or analysis with the project team/Owner.The above pavement sections are initial recommendations and may be accepted and/or modified by the site Civil Engineer based on the actual finished site grading elevations and/or the Owner's preferences. Stormwater Infiltration Potential From the exploration test pits, six representative soil samples were selected and mechanically tested for grain size distribution and calculation according to the soil grain size analysis method, Section V-5.4 of the Stormwater Management Manual for Western Washington [Manual].This document is the current stormwater manual adopted by the City of Arlington. It should be noted that the rates presented below are representative of loose soil conditions and do not consider dense or compacted soil conditions. In our experience, infiltration rates based on grain size analyses overestimate the actual infiltration rate of the soil. Conceptual Infiltration Results In order to assist with the project design, we are providing a preliminary infiltration rate using the soil grain size analysis method, Section V-5.4 of the 2019 Stormwater Management Manual for Western Washington [Manual]. This rate is to be used in the conceptual sizing of the planned facilities. It should be noted that the grain size analysis method does not take into account the density of a given soil unit or the effects of groundwater mounding. Thus, additional considerations may be required upon initial sizing of a facility. From the explorations in the subject area, six representative soil samples were selected from native soils and mechanically tested for grain size method as referenced above. The total correction factor applied to the initial saturated hydraulic conductivity(Ksat) values was 0.18 based on the below variables. • Site variability and number of locations tested (CFv): 0.5 • Test Method—Grain Size Analysis (CFt): 0.4 • Degree of influent control to prevent siltation and bio-buildup (CFm): 0.9 Based on the grain size approach with the referenced correction factors incorporated, a preliminary infiltration rate of 4.4 inches per hour could be used in the conceptual sizing of a stormwater management facility within 4 feet of the existing ground surface. If facilities are planned below 4 feet of existing site grades, a preliminary infiltration rate of 9 inches per hour may be used. At the time of this report, Certerra does not have a facility size, depth, or location. However, the rate provided should be suitable for initial sizing of infiltration facilities provided that additional studies are conducted once bottom-of-facility elevations have been established. Certerra should be contacted to provide additional input upon the completion of initial stormwater design services by the Civil Engineer. Stormwater Treatment The stormwater facilities on-site may require some form of pollutant pretreatment with an amended soil prior to on-site infiltration or offsite discharge. The reuse of on-site topsoil is often the most sustainable and cost-effective method for pollutant treatment purposes. Cation exchange capacities,organic contents,and pH of site subsurface soils were also tested to determine possible pollutant treatment suitability. Cation exchange capacity, organic content, and pH tests were performed by Northwest Agricultural Consultants on four soil samples collected from the project site. A summary of the laboratory test results is presented in Table 2 below. Suitability for onsite pollutant treatment is determined in accordance with SSC-6 of the Manual. Soils with an organic content of greater than or equal to 1 percent and a cation exchange capacity of greater than or equal to 5 meq/100 grams are characterized as suitable for stormwater treatment. Based on the results shown in Table 2, topsoil and weathered Marysville certerra.com 20527 67"Avenue NE,Arlington,WA 98223 14 1 CERTERRA Materially BetterT" f GEOTEST Sand are suitable for stormwater treatment. However, low rates of infiltration should be anticipated in the topsoil due to these soils' high silt contents. Table 2: Cation Exchange Capacity,Organic Content, and . TP-1 1.5 Weathered 6.1 2.63 7 Marysville Sand TP-2 0.5 Topsoil 19.5 9.70 5.4 TP-3 1.5 Weathered 7.0 2.70 6.2 Marysville Sand TP-5 0.5 Topsoil 6.0 2.71 6.1 On-site soils can be amended by mixing higher silt content soils or adding mulch (or other admixtures)to elevate the cation exchange capacity and organic contents. On-site amended soil requires additional testing to confirm compliance with ecological regulations. Certerra is available to perform additional laboratory testing as part of an expanded scope of services if the soil is to be amended. Alternatively, the owner may elect to import amended soils with the desired properties for planned treatment facilities. Geotechnical Consultation and Construction Monitoring Certerra recommends that we be involved in the project design review process. The purpose of the review is to verify that the recommendations presented in this report are understood and incorporated in the design and specifications. We also recommend that geotechnical construction monitoring services be provided. These services should include observation by Certerra personnel during Structural Fill placement, compaction activities and subgrade preparation operations to confirm that design subgrade conditions are obtained beneath the areas of improvement. Periodic field density testing should be performed to verify that the appropriate degree of compaction is obtained. The purpose of these services is to observe compliance with the design concepts, specifications, and recommendations of this report. In the event that subsurface conditions differ from those anticipated before the start of construction, Certerra Services would be pleased to provide revised recommendations appropriate to the conditions revealed during construction. Certerra is available to provide a full range of materials testing and special inspection during construction as required by the local building department and the International Building Code. This may include specific construction inspections on materials such as reinforced concrete, reinforced masonry,wood framing and structural steel. These services are supported by our fully accredited materials testing laboratory. Use of This Report Certerra Services has prepared this report for the exclusive use of Scott Wammack, Grandview North LLC, and their design consultants for specific application to the design of the proposed development located at the parcel #31052100202000 in Arlington,Washington.Use of this report by others is at the user's sole risk.This report is not applicable to other site locations. Our services are conducted in accordance with accepted practices of the geotechnical engineering profession; no other warranty, express or implied, is made as to the professional advice included in this report. Our site explorations indicate subsurface conditions at the dates and locations indicated. It is not warranted that these conditions are representative of conditions at other locations and times. The analyses, conclusions, and recommendations contained in this report are based on site conditions to the limited depth and time of our explorations, a geological reconnaissance of the area,and a review of previously published geological information for the site. If variations in subsurface conditions are encountered during construction that differ from those contained within this report, Certerra should be allowed to review the recommendations and, if necessary, make revisions. If there is a substantial lapse of time between certerra.com 20527 67"Avenue NE,Arlington,WA 98223 15 f CERTERRA Materially BetterT" f GEOTEST submission of this report and the start of construction, or if conditions change due to construction operations at or adjacent to the project site, we recommend that we review this report to determine the applicability of the conclusions and recommendations contained herein. The earthwork contractor is responsible to perform all work in conformance with all applicable WISHA/OSHA regulations. Certerra Services, Inc. is not responsible for job site safety on this project, and this responsibility is specifically disclaimed. Attachments: Figure 1 Vicinity Map Figure 2 Site and Exploration Plan Figure 3 Typical Footing and Wall Drain Section Figure 4 Soil Classification System and Key Figures 5—7 Test Pit Exploration Logs Figures 8—9 Grain Size Test Data Attachment NW Agricultural Consultants Test Results Attachment Report Limitations and Guidelines for its Use (3 Pages) References American Society of Civil Engineers, (2017). Minimum design loads and associated criteria for buildings and other structures:ASCE/SEI 7-16. Reston, Virginia: American Society of Civil Engineers. American Society for Testing and Materials (ASTM). Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System). ASTM D2487— 17el. American Society for Testing and Materials (ASTM). Standard Practice for Description and Identification of Soils (Visual- Manual Procedures).ASTM D2488— 17el. American Society for Testing and Materials (ASTM). (2017). ASTM D6938, Standard Methods for In-Place Density and Water Content of Soil and Soil-Aggregate by Nuclear Methods. American Society for Testing and Materials (ASTM). Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort. ASTM D1557— 12el. Arlington Municipal Code, Chapter 20.93 (Critical Areas Ordinance), City of Arlington (Washington). Accessed via https:Hlibrary.municode.com/wa/arlington/codes, in June 2025. Atwater, B.F., and Haley, E. H., (1997) Recurrence Intervals for Great Earthquakes of the Past 3,500 Years at Northeastern Willapa Bay, Washington. USGS Survey Professional Paper 1576. Gariepy, D., Graul, C. Heye, A., Howie, D., Labib, F. &Song, K. (n.d.) 2019. Stormwater Management Manual for Western Washington (2019 SMMWW) (pp. 1-1108) (United States, Washington Department of Ecology). Minard, J.P., 1985, Geologic map of the Arlington West 7.5 minute quadrangle, Snohomish County, Washington, U.S. Geological Survey, Miscellaneous Field Studies Map MF-1743, 1:24,000 USDA Web Soil Survey. (August 31, 2021). Retrieved June 2025, from https.Ilwebsoilsurvey.sc.egov.usda.govIAppIWebSoilSurvey aspx. Washington Administrative Code (WAC). (2020). WAC 296-155-6640, Retrieved June 2025,from https:Happ.leg.wa.gov/wac/default.aspx?cite=296-155-66403. Washington State Department of Natural Resources - Online Web Services. Washington Geologic Information Portal. Retrieved in June 2025. certerra.com 20527 67"Avenue NE,Arlington,WA 98223 16 VW Aff 544 Map Referenced from Google Terrain using QGIS 3.34.5-Prizren ill-ICI ♦. T 7� 542 Ferndale 539 ` Mt S h ksanY"O� Deming Marietta Alderwood ' 54�1 Mt Baker'Q �y � Jr Ilt Bellingham Sudden Valleyi; Eastsound Orcas lsland F �, Bow if •` 7 i Juan .. , f island —' " • '� � �. � Concrete Anacortes 2d -� HamiltonMarblemount Sedro-Woolley Lopez Island Burlington ., '' 't /� Rockport Fidalgo'lsland Mt Vernon La Conner 1� = 5 PROJECT LOCATION 5'V Mans(ord Oak Harbor Stanwood ' ,; � Darrington Coupevllle J on L Camano ene,s Vc Port Townsend 4 • quim Granite Falls 1 ' - Baker-Snoyual(TI Port Marysville jJ� 1�'National�+ores f Hadlock Irondale 5.s Whidbey Lake Stevens ' Island T . Everett _ - ;-"�_. •� , , I r ,, _ -4 _ I J •,1 ,,Monroe �' .' ' I-� Edmonds �, s ,y ► IT ,.'ndex301 Shor'eline Bothell Bari�g1' Bangor Base �Skyko t r r • ► Redmond r �i Seabeck BainbridgeIsland Seattle s , , A r �� 0 7.5 15 22.5 miNonni Orr J Wirth Pon Date: 6-18-2025 By: JV Scale: As Shown Project VICINITY CERTERRAHOLMAN RE 25OVERY CENTER II Figure GEOTEST PARCEL No. 31052100202000 ARLINGTON,WASHINGTON doo I F „eA .c. il Xkldl� • / ' � � 1 W • \ yrgY Y 2 \ N1P a' V 1o•, Cwr L 0 75 150 225 ft ProjectDate: 6-18-2025 Scale: AsShown CERTERRA TP-# Approximate Test Pit Location SITE AND EXPLORATION PLAN 25-1507 HOLMANRECOVERY PARCELNo. 31052100202000 CONCEPTUAL FOOTINGS WITH INTERIOR SLAB-ON-GRADE ' ' < Typical Framing Compacted Low-Permeability Soil (12 inch minimum) Floor Slab or Pavement •,•,',' , , , , , , , , , , , , , , , , (2 inch minimum) . . . . . . . . . . . . . . . . . . . , , , , , , , , , , , , , , , , , Slope to drain away Vapor Barrier from structure. •.f:f:f:f:f:f:;:f:;:f:f:f:f. . f f.;: .;. _ — — ',',',' ti'ti•ti•ti•ti•ti•ti•ti•ti•ti•ti•ti•ti•ti•ti ti•ti•ti•ti•ti•ti•ti•ti•ti•ti•ti•ti•ti•ti• — r•r•r•r•r•r•1•r•r•r•r•r•r•r• 1•r•r•r•r•r•r•r•r•1•r•r•r•r•1 •+•+•�• ti.ti.ti.ti.ti.ti.ti.ti.ti.ti.ti.ti.ti.ti.ti. .ti.ti.ti.ti.ti.ti.ti.ti.ti.ti.ti.ti•tilti.l Gravel Capillary Break minimum,typically clear crushed) Suitable Soil / +,+,+• . •,•,• •. •. Free Draining Sand + +' and Gravel Fill Approved Non-woven Geotextile Filter Fabric + + + + + + + + (18 inch minimum fabric lap) ' ' ' Suitable Soil Drainage Material (Drain Rock or Clear Crushed Rock w/no fines) Appropriate Waterproofing Applied to Exterior of Wall Four Inch Diameter,Perforated,Rigid PVC Pipe (Perforations oriented down directed to suitable discharge) Notes: Footings should be properly buried for frost protection in accordance with International Building Code or local building codes (Typically 18 inches below exterior finished grades). This figure is not intended to be representative of a design. This figure is intended to present concepts that can be incorporated into a functional foundation drain designed by a Civil Engineer. In all cases, refer to the Civil plan sheet for drain details and elevations. This footing drain detail may need to be modified from this conceptual drawing to fit the dimensions of the planned footing and slab configuration. Date:6-18-2025 By: JV Scale: None Project CONCEPTUAL FOOTING & WALL DRAIN SECTION 25-1507 CERTERRA HOLMAN RECOVERY CENTER II 1 GEOTEST PARCEL No.31052100202000 Figure ARLINGTON,WASHINGTON 3 Soil Classification System Uscs MAJOR GRAPHIC LETTER TYPICAL DIVISIONS SYMBOL SYMBOL DESCRIPTIONS(')(2) GRAVEL AND CLEAN GRAVEL o o o°o;o GW Well-graded gravel;gravel/sand mixture(s);little or no fines GRAVELLY SOIL (Little or no fines) o,6 o�?o GP Poorly graded gravel;gravel/sand mixture(s);little or no fines O 'N ° ° . m y .a (More than 50%of coarse fraction retained GRAVEL WITH FINES GM Silty gravel;gravel/sand/silt mixture(s) M a)W E o on No.4 sieve) (Appreciable amount of z o N fines) GC Clayey gravel;gravel/sand/clay mixture(s) o w SAND AND CLEAN SAND SW Well-graded sand;gravelly sand;little or no fines CO c;t SANDY SOIL (Little or no fines) QSP Poorly graded sand;gravelly sand;little or no fines O 2 (More than 50%of U_ m coarse fraction passed SAND WITH FINES SM Silty sand;sand/siltmixture(s) through No.4 sieve) (Appreciable amount of fines) SC Clayey sand;sand/clay mixture(s) Inorganic silt and very fine sand;rock flour;silty or clayey fine f6 ��', SILT AND CLAY ML sand or clayey silt with slight plasticity .N Inorganic clay of low to medium plasticity;gravelly clay;sandy 0 E N (Liquid limit less than 50) C�' clay;silty clay;lean clay W ° o z o z QL Organic silt;organic,silty clay of low plasticity O C N � 0ca0 C�7 r� SILT AND CLAY MH Inorganic silt;micaceous or diatomaceous fine sand CH Inorganic clay of high plasticity;fat clay LL 5 E (Liquid limit greater than 50) OH Organic clay of medium to high plasticity;organic silt HIGHLY ORGANIC SOIL PT Peat;humus;swamp soil with high organic content GRAPHIC LETTER OTHER MATERIALS SYMBOL SYMBOL TYPICAL DESCRIPTIONS PAVEMENT AC Or PC Asphalt concrete pavement or Portland cement pavement ROCK RK Rock(See Rock Classification) WOOD WD Wood,lumber,wood chips DEBRIS O O O Dg I Construction debris,garbage Notes: 1. Soil descriptions are based on the general approach presented in the Standard Practice for Description and Identification of Soils(Visual-Manual Procedure), as outlined in ASTM D 2488.Where laboratory index testing has been conducted,soil classifications are based on the Standard Test Method for Classification of Soils for Engineering Purposes,as outlined in ASTM D 2487. 2. Soil description terminology is based on visual estimates(in the absence of laboratory test data)of the percentages of each soil type and is defined as follows: Primary Constituent: >50%-"GRAVEL,""SAND,""SILT,""CLAY,"etc. Secondary Constituents: >30%and<50%-"very gravelly,""very sandy,""very silty,"etc. >12%and<30%-"gravelly,""sandy,""silty,"etc. Additional Constituents: > 5%and<12%-"slightly gravelly,""slightly sandy,""slightly silty,"etc. < 5%-"trace gravel,""trace sand,""trace silt,"etc.,or not noted. Drilling and Sampling Key Field and Lab Test Data SAMPLE NUMBER&INTERVAL SAMPLER TYPE Code Description Code Description Sample Identification Number a 3.25-inch O.D.,2.42-inch I.D.Split Spoon PP=1.0 Pocket Penetrometer,tsf b 2.00-inch O.D.,1.50-inch I.D.Split Spoon TV=0.5 Torvane,tsf Recovery Depth Interval c Shelby Tube PID=100 Photoionization Detector VOC screening,ppm 1� 14-- Sample Depth Interval d Grab Sample W=10 Moisture Content,% J e Other-See text if applicable D=120 Dry Density,pcf Portion of Sample Retained 1 300-lb Hammer,30-inch Drop -200=60 Material smaller than No.200 sieve,% for Archive or Analysis 2 140-lb Hammer,30-inch Drop GS Grain Size-See separate figure for data 3 Pushed AL Atterberg Limits-See separate figure for data 4 Other-See text if applicable GT Other Geotechnical Testing Groundwater CA Chemical Analysis L7 Approximate water elevation at time of drilling(ATD)or on date noted. Groundwater ATD levels can fluctuate due to precipitation,seasonal conditions,and other factors. Holman Recovery Center II Figure 1 CERTERRA Parcel No. 31052100202000 Soil Classification System and Key 1 GEofESr 4 Arlington, Washington TP-1 SAMPLE DATA SOIL PROFILE GROUNDWATER o E— a E -6 Excavation Method- Tracked Excavator T za, > v U In Ground Elevation(ft). -130 aa, E S E o M N Excavated By: Client Provided/JV V106 In H C7 D 0 SM Loose,dark brown,damp,silty SAND with = d SP_ � numerous organics(Topsoil) /— ------------------ Groundwater not encountered. SM Medium dense,orange-brown,damp, = d slightly silty SAND with occasional organics 2 SP_ (Weathered Marysville Sand) ______- - SM Medium dense,gray-brown,damp,slightly silty SAND(Marysville Sand) = d 4 Certerra observed a decrease in silt content below 4 feet. 6 = d g d Test Pit Completed 05/28/25 Excavation terminated at planned depth. Total Depth of Test Pit=8.0 ft. TP-2 SAMPLE DATA SOIL PROFILE GROUNDWATER o E— a E -6 Excavation Method. Tracked Excavator T _v " v U T Ground Elevation(ft). -130 Y a cu Y a 0 FCL VI v E N Excavated By: Client Provided/JV 0 V)Off V) H CJ 0 SM Loose,dark brown,damp,silty SAND with = d SM numerous organics(Topsoil) �— ------------------ Groundwater not encountered. Medium dense,orange-brown,damp,silty W=10 SAND with occasional organics,trace gravel 2 = d GS (Weathered Marysville Sand) SP- Medium dense,gray-brown,damp,slightly SM silty SAND(Marysville Sand) 4 = d Certerra observed a decrease in silt content below 4 feet. 6 = d Certerra observed an increase in gravel content below 6 feet. g d Test Pit Completed 05/28/25 Excavation terminated at planned depth. Total Depth of Test Pit=8.0 ft. Notes: 1.Stratigraphic contacts are based on field interpretations and are approximate. 2.Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3.Refer to"Soil Classification System and Key"figure for explanation of graphics and symbols. 4.Approximate elevations obtained from CalTopo interactive web portal. Holman Recovery Center II Figure 1 CERTERRA Parcel No. 31052100202000 Log of Test Pits f GEOlE51 Arlington, Washington TP-3 SAMPLE DATA SOIL PROFILE GROUNDWATER o E— a E -6 Excavation Method- Tracked Excavator T za, > v U N Ground Elevation(ft). -130 L N 0 t CL v E N Excavated By: Client Provided/JV 0 N 06 In H C7 D 0 SM Loose,dark brown,damp,silty SAND with = d Sp_ numerous organics(Topsoil) ———__/^ Groundwater not encountered. SM Medium dense,orange-brown,damp, = d _ slightly silty SAND with occasional organics, 2 SP- trace ravel Weathered Marysville Sand --g— -----r`/----�—— = d W=4 SM Medium dense,gray-brown,damp,slightly GS silty,gravelly SAND(Marysville Sand) 4 Certerra observed a decrease in silt content below 4 feet. 6 = d 8 d W-4 GS Test Pit Completed 05/28/25 Excavation terminated at planned depth. 10 Total Depth of Test Pit=9.0 ft. TPA SAMPLE DATA SOIL PROFILE GROUNDWATER o E— a E -6 Excavation Method. Tracked Excavator T _v v Y T Ground Elevation(ft). -130 v E S E N Excavated By: Client Provided/JV in 0 Vn H C7 0 SM Loose,dark brown,damp,silty SAND with = d Gp- \ numerous organics(Topsoil) ----__i- ------------ Groundwater not encountered. W=7 GM Medium dense to dense,dark brown, = d GS slightly silty,very sandy GRAVEL with 2 SP- \ occasional organics(Uncontrolled Fill) = d GS 9 SM Certerra observed filter fabric at 2 feet.---J� SP \ Medium dense,orange-brown,damp, / 4 slightly silty SAND with occasional organics, / = d \trace gravel(Weathered Marysville Sand) _J Medium dense,gray-brown,damp,SAND (Marysville Sand) 6 = d Certerra observed an increase in gravel and cobble content below 7 feet. 8 = d Test Pit Completed 05/28/25 Excavation terminated at planned depth. 10 Total Depth of Test Pit=8.5 ft. Notes: 1.Stratigraphic contacts are based on field interpretations and are approximate. 2.Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3.Refer to"Soil Classification System and Key"figure for explanation of graphics and symbols. 4.Approximate elevations obtained from CalTopo interactive web portal. Holman Recovery Center II Figure 1 CERTERRA Parcel No. 31052100202000 Log of Test Pits ��11 .r GEorESr 6 Arlington, Washington \J TP-5 SAMPLE DATA SOIL PROFILE GROUNDWATER o E— a E -6 Excavation Method- Tracked Excavator T za, > v U N Ground Elevation(ft). -130 aa, E S E o M N Excavated By: Client Provided/JV V106 In H C7 D 0 SM Loose,dark brown,damp,silty SAND with d SM numerous organics(Topsoil) /— d D------------------ — Groundwater not encountered. Sp- \ Medium dense to dense,dark brown,damp, / = d W=7 SM \ gravelly,silty SAND with occasional organics / 2 GS Sp- \ \(Uncontrolled Fill)-----------� /— SM \ Medium dense,orange-brown,damp, / \slightly silty SAND with occasional organics, / \trace gravel(Weathered Marysville Sand) _— 4 = d Medium dense,gray-brown,damp,slightly silty SAND(Marysville Sand) Certerra observed a decrease in silt content below 4 feet. 6 = d g d Test Pit Completed 05/28/25 Excavation terminated at planned depth. Total Depth of Test Pit=8.0 ft. TP-6 SAMPLE DATA SOIL PROFILE GROUNDWATER o E— a E -6 Excavation Method. Tracked Excavator T _v " v U T Ground Elevation(ft). -130 v E N Excavated By: Client Provided/JV 0 V)0.6 !n H CJ D 0 SM Loose,dark brown,damp,silty SAND with = d SM ',-`umerous organics(Topsoil)______ /— -- Groundwater not encountered. AIL Medium dense to dense,dark brown,damp, Sp_ \ silty SAND with occasional organics 2 = d SM \(Uncontrolled Fill) Sp- \ Medium dense,orange-brown,damp, / SM \ slightly silty SAND with occasional organics / \(_Weathered Marysville Sand)_------ 4 = d GS4 Medium dense,gray-brown,damp,slightly silty SAND with trace gravel(Marysville Sand) Certerra observed a decrease in silt content 6 = d below 4 feet. Certerra observed a decrease in gravel content below 6 feet. g d Test Pit Completed 05/28/25 Excavation terminated at planned depth. Total Depth of Test Pit=8.0 ft. Notes: 1.Stratigraphic contacts are based on field interpretations and are approximate. 2.Reference to the text of this report is necessary for a proper understanding of subsurface conditions. 3.Refer to"Soil Classification System and Key"figure for explanation of graphics and symbols. 4.Approximate elevations obtained from CalTopo interactive web portal. Holman Recovery Center II Figure r CERTERRA Parcel No. 31052100202000 Log of Test Pits 7 1 GE°TE5` Arlington, Washington I U.S.SIEVE OPENING IN INCHES I U.S.SIEVE NUMBERS I HYDROMETER 6 4 3 2 1.5 1 3A 112 3 4 6 810 1416 20 30 40 50 60 100 140 200 100 90 80 70 60 T Q ii50 c U 0040 30 20 10 0 100 10 1 0.1 0.01 0.001 Grain Size in Millimeters Cobbles Gravel Sand Silt or Clay coarse fine coarse medium fine Point Depth Classification ILL PL PI C,� Cu • TP-2 2.0 Silty SAND (SM) 1.62 5.92 III TP-3 3.0 Slightly silty,gravelly SAND (SP-SM) 1.13 3.12 A TP-3 8.8 Gravelly SAND (SP) 0.89 8.03 * TP-4 1.5 Slightly silty,very sandy GRAVEL (GP-GM) 0.16 132.51 O TP-4 2.5 Slightly silty SAND (SP-SM) 1.52 4.57 Point Depth D D D D D %Coarse %Fine %Coarse %Medium %Fine %Fines p 90 60 50 30 10 Gravel Gravel Sand Sand Sand 0 TP-2 2.0 0.855 0.338 0.277 0.177 0.057 0.0 1.0 2.2 25.4 58.4 12.9 III TP-3 3.0 11.611 0.376 0.322 0.226 0.12 4.6 9.2 1.8 16.7 62.0 5.7 A TP-3 8.8 10.91 1.782 1.252 0.594 0.222 3.3 18.1 15.3 41.7 17.7 3.9 * TP-4 1.5 21.662 10.598 5.45 0.37 0.08 19.2 32.4 4.4 11.3 23.0 9.7 O TP-4 2.5 0.772 0.357 0.306 0.206 0.078 0.0 0.7 1.4 26.8 61.4 9.7 C, = D3o2/(D60* D1o) To be well graded: 1 < C,< 3 and C,, = D6o/D10 C, > 4 for GW or C, > 6 for SW Holman Recovery Center II Figure 1 CERTERRA Parcel No. 31052100202000 Grain Size Test Data 1 GEorEsr Arlington, Washington 8 U.S.SIEVE OPENING IN INCHES I U.S.SIEVE NUMBERS I HYDROMETER 6 4 3 2 1.5 1 3A 1/2 3 4 6 810 1416 20 30 40 50 60 100 140 200 100 90 80 70 60 T Q 50 ii c U a 40 30 20 10 0 100 10 1 0.1 0.01 0.001 Grain Size in Millimeters Cobbles Gravel Sand Silt or Clay coarse fine coarse medium fine Point Depth Classification ILL PL PI C,� Cu • TP-5 1.8 Slightly silty SAND (SP-SM) 1.31 5.31 m TP-6 4.0 Slightly silty SAND (SP-SM) 1.14 4.06 Point Depth D D D D D %Coarse %Fine %Coarse %Medium %Fine %Fines p 90 60 50 30 10 Gravel Gravel Sand Sand Sand 0 TP-5 1.8 1.099 0.37 0.299 0.184 0.07 0.0 1.3 3.2 28.9 56.0 10.6 m TP-6 4.0 1.743 0.598 0.499 0.317 0.147 0.0 4.3 3.7 50.9 36.2 5.0 C, = D3o2/(D60" D1o) To be well graded: 1 < C,< 3 and C,, = D6o/D10 C, > 4 for GW or C, > 6 for SW Holman Recovery Center II Figure r r ceotEsr cEFiTERFiA Parcel No. 31052100202000 Grain Size Test Data . Arlington, Washington Northwest Agricultural Consultants 24SA9936 Report: 72778-1 509.7817450 www^wagc^m lab@nwag.mm GEOTEST SERVICES INC Date: 2025-05-30 741 MARINE DR Project Name: Holman Recovery Center II BELLINGHAM,WA 98225 Project Number: 25-1507 Sample Sulfate pH Resistivity OM CEC Chloride Moisture Sand Silt Clay Class ID ma/kci S.U. ohm-m % me /100 m /k % % % % TP-1 @ 1.5' 6.1 2.63 6.1 TP-2 @ 0.5' 5.4 9.70 19.5 TP-3 1.5' 6.2 2.70 7.0 TP-5 @ 0.5' 6.1 2.71 6.0 Analyte Sulfate pH Resistivity OM CEC Chloride Moisture Sand Silt Clay Class Method SM-4500 SO4 E SM 4500-H+B SM 2510 B ASTM D2974 EPA 9081 ASTM D512 Gravimetric Hydrometer Hydrometer Hydrometer Hydrometer 1 CERTERRA 1 GEOTEST REPORT LIMITATIONS AND GUIDELINES FOR ITS USE ' Subsurface issues may cause construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help: Geotechnical Services are Performed for Specific Purposes, Persons, and Projects At Certerra our geotechnical engineers and geologists structure their services to meet specific needs of our clients. A geotechnical engineering study conducted for a civil engineer may not fulfill the needs of an owner,a construction contractor or even another civil engineer. Because each geotechnical engineering study is unique, each geotechnical engineering report is unique, prepared solely for the client. No one except you should rely on your geotechnical engineer who prepared it.And no one—not even you—should apply the report for any purpose or project except the one originally contemplated. Read the Full Report Serious problems have occurred because those relying on a geotechnical engineering report did not read it all. Do not rely on an executive summary. Do not read selected elements only. A Geotechnical Engineering Report is Based on a Unique Set of Project-Specific Factors Certerra's geotechnical engineers consider a number of unique, project-specific factors when establishing the scope of a study. Typical factors include: the clients goals, objectives, and risk management preferences; the general nature of the structure involved its size, and configuration; the location of the structure on the site; and other planned or existing site improvements, such as access roads, parking lots, and underground utilities. Unless Certerra, who conducted the study specifically states otherwise, do not rely on a geotechnical engineering report that was: • not prepared for you, • not prepared for your project, • not prepared for the specific site explored, or • completed before important project changes were made. Typical changes that can erode the reliability of an existing geotechnical engineering report include those that affect: • the function of the proposed structure,as when it's changed,for example,from a parking garage to an office building, or from a light industrial plant to a refrigerated warehouse, • elevation, configuration, location, orientation, or weight of the proposed construction, • alterations in drainage designs; or • composition of the design team;the passage of time; man-made alterations and construction whether on or adjacent to the site; or by natural alterations and events, such as floods, earthquakes or groundwater fluctuations; or project ownership. Always inform Certerra's geotechnical engineer of project changes—even minor ones—and request an assessment of their impact. Geotechnical engineers cannot accept responsibility or liability for problems that occur because their reports do not consider developments of which they were not informed. Subsurface Conditions Can Change This geotechnical or geologic report is based on conditions that existed at the time the study was performed. Do not rely on the findings and conclusions of this report, whose adequacy may have been affected by: the passage of time; by man- made events, such as construction on or adjacent to the site; or by natural events, such as floods, earthquakes, or 1 Information in this document is based upon material developed by ASFE,Professional Firms Practicing in the Geosciences(asfe.org) f CERTERRA f GEOTEST groundwater fluctuations. Always contact Certerra before applying the report to determine if it is still relevant. A minor amount of additional testing or analysis will help determine if the report remains applicable. Most Geotechnical and Geologic Findings are Professional Opinions Our site exploration identifies subsurface conditions only at those points where subsurface tests are conducted or samples are taken. Certerra's engineers and geologists review field and laboratory data and then apply their professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ—sometimes significantly — from those indicated in your report. Retaining Certerra who developed this report to provide construction observation is the most effective method of managing the risks associated with anticipated or unanticipated conditions. A Report's Recommendations are Not Final Do not over-rely on the construction recommendations included in this report. Those recommendations are not final, because geotechnical engineers or geologists develop them principally from judgment and opinion. Certerra's geotechnical engineers or geologists can finalize their recommendations only by observing actual subsurface conditions revealed during construction. Certerra cannot assume responsibility or liability for the report's recommendations if our firm does not perform the construction observation. A Geotechnical Engineering or Geologic Report may be Subject to Misinterpretation Misinterpretation of this report by other design team members can result in costly problems. Lower that risk by having Certerra confer with appropriate members of the design team after submitting the report. Also, we suggest retaining Certerra to review pertinent elements of the design teams plans and specifications. Contractors can also misinterpret a geotechnical engineering report. Reduce that risk by having Certerra participate in pre-bid and preconstruction conferences, and by providing construction observation. Do not Redraw the Exploration Logs Our geotechnical engineers and geologists prepare final boring and testing logs based upon their interpretation of field logs and laboratory data. To prevent errors of omissions,the logs included in this report should never be redrawn for inclusion in architectural or other design drawings. Only photographic or electronic reproduction is acceptable; but recognizes that separating logs from the report can elevate risk. Give Contractors a Complete Report and Guidance Some owners and design professionals mistakenly believe they can make contractors liable for unanticipated subsurface conditions by limiting what they provide for bid preparation. To help prevent costly problems, give contractors the complete geotechnical engineering report, but preface it with a clearly written letter of transmittal. In that letter, consider advising the contractors that the report was not prepared for purposes of bid development and that the report's accuracy is limited; encourage them to confer with Certerra and/or to conduct additional study to obtain the specific types of information they need or prefer. A pre-bid conference can also be valuable. Be sure contractors have sufficient time to perform additional study. Only then might you be in a position to give contractors the best information available,while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. In addition, it is recommended that a contingency for unanticipated conditions be included in your project budget and schedule. Read Responsibility Provisions Closely Some clients, design professionals, and contractors do not recognize that geotechnical engineering or geology is far less exact than other engineering disciplines. This lack of understanding can create unrealistic expectations that can lead to disappointments, claims, and disputes. To help reduce risk, Certerra includes an explanatory limitations section in our f CERTERRA f GEOTEST reports. Read these provisions closely. Ask questions and we encourage our clients or their representative to contact our office if you are unclear as to how these provisions apply to your project. Environmental Concerns Are Not Covered in this Geotechnical or Geologic Report The equipment, techniques, and personnel used to perform an environmental study differ significantly from those used to perform a geotechnical or geologic study. For that reason, a geotechnical engineering or geologic report does not usually relate any environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated containments, etc. If you have not yet obtained your own environmental information, ask your geotechnical consultant for risk management guidance. Do not rely on environmental report prepared for some one else. Obtain Professional Assistance to Deal with Biological Pollutants Diverse strategies can be applied during building design, construction, operation, and maintenance to prevent significant amounts biological pollutants from growing on indoor surfaces. Biological pollutants includes but is not limited to molds, fungi, spores, bacteria and viruses. To be effective, all such strategies should be devised for the express purpose of prevention, integrated into a comprehensive plan, and executed with diligent oversight by a professional biological pollutant prevention consultant. Because just a small amount of water or moisture can lead to the development of severe biological infestations, a number of prevention strategies focus on keeping building surfaces dry. While groundwater,water infiltration, and similar issues may have been addressed as part of this study, the geotechnical engineer or geologist in charge of this project is not a biological pollutant prevention consultant;none of the services preformed in connection with this geotechnical engineering or geological study were designed or conducted for the purpose of preventing biological infestations.