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Exhibit 20 - Stormwater Drainage Report
4 LAND TECHNOLOGIES, INC. 0TECHHOL000 PLANNING • PERMITTING • ENGINEERING 7M MAKING A"WAY"OUT OF"NO WAY" Lindsay Investments, LLC. 8326 172nd St NE, Arlington, WA 98223 PFN # Preliminary Plat Submittal: February 2026 Stormwater Site Plan Report for Lindsay Subarea Plan Lindsay Investments , LLC . R S. FOS �7 WA0�`�-s 2 Prepared by: Tyler Foster, P.E. 53 26 360-652-9727 EmaII:Tyler@Iandtechway.com FSS�ONA�ENG' 0210 2026 18820 Third Avenue NE, Arlington WA 98223 voice: 360.652-9727 fax:360.652.7553 Table of Contents Section 1—Summary and Minimum Requirements............................................................. 1-1 1.1 Project Description............................................................................................................. 1-1 1.2 Project Data Summary........................................................................................................ 1-1 1.3 Construction Activities ....................................................................................................... 1-2 1.4 Minimum Requirements and Thresholds........................................................................... 1-4 Section 2- MR-1: PREPARE STORMWATER SITE PLAN..........................................................2-1 2.1 Existing Site Conditions ...................................................................................................... 2-1 Section 3— MR-2: Stormwater Pollution Prevention Plan....................................................3-1 3.1 Storm Water Pollution Prevention Plan............................................................................. 3-1 Section 4 - MR-3: Source Control of Pollution......................................................................4-1 Section 5 - MR-4: Preserve Natural Drainage Systems and Outfalls...................................... 5-1 Section 6 - MR-5: On-site Stormwater Management ...........................................................6-1 Section 7 - MR-6: Runoff Treatment....................................................................................7-1 Section 8 - MR-7: Flow Control............................................................................................8-1 8.1 Flow Control ....................................................................................................................... 8-1 Section 9 - MR-8: Wetlands Protection................................................................................9-2 Section 10 - MR-9: Operation and Maintenance................................................................ 10-1 Section11 - Support Data ................................................................................................. 11-1 11.1 Maps & Figures............................................................................................................... 11-1 Section12 Support Data................................................................................................... 12-6 12.1 Soils................................................................................................................................. 12-7 12.2 Reference Documents.................................................................................................. 12-11 12.3 Topographic Data ......................................................................................................... 12-11 12.4 Continuous Simulation Modeling................................................................................. 12-12 12.5 Modeling Methodology................................................................................................ 12-12 Section 13 - Software Output.......................................................................................... 13-14 13.1 West Basin.................................................................................................................... 13-15 13.2 Southwest Basin ........................................................................................................... 13-26 13.3 Northeast Basin............................................................................................................ 13-40 Drainage Report Lindsay Project 1 06-Feb-2026 1-i Figures Figure1 -Vicinity Map....................................................................................................................11-1 Figure 2 - Existing Conditions..........................................................................................................11-2 Figure 3 - NRCS Soil Map (Not to Scale)..........................................................................................11-2 Figure4 - Site Plan ..........................................................................................................................11-3 Figure 5 - Stormwater Basin Map for Proposed Facilities ..............................................................11-4 Figure 6— Existing PreDeveloped Basin Map .................................................................................11-5 Tables Table 1— Project Location Data........................................................................................................1-3 Table 2 - Project Theshhold Data Summary .....................................................................................1-3 Table3 - Soil Table..........................................................................................................................12-7 Drainage Report Lindsay Project 1 06-Feb-2026 1-ii Section 1 — Summary and Minimum Requirements 1 .1 Project Description Lindsay Project 1, is a proposed preliminary plat within the Lindsay subarea plan. The preliminary plat will reside on a 32.26-acres of land in the City of Arlington. The parcels are owned by Lindsay Investments, LLC. The development is located on Parcel Numbers 310525-002-006-00, 310526- 001-001-00, -002-00, -022-00, -023-00 and bears the address 8326 172nd St NE, Arlington, WA 98223. The development will contain 12.17-acres impervious surface of which 6.11-acres will be pollution generating and 6.06-acres will be non-pollution generating impervious surface. The development of the parcels will consist of single family homes, roads, driveways, and recreational park features. The neighborhood will include LID stormwater management features and conform to the requirements set forth in Arlington Municipal Code (AMC). The project will incorporate the preferred options for On-site Stormwater Management to the maximum extent feasible in accordance with the 2019 Stormwater Management Manual for Western Washington (SMMWW). The most preferred option from the Manual is Full Dispersion, BMP T5.30. A portion of the site will incorporate Full Dispersion. The second preferred option for non-pollution generating impervious surface is Rooftop Dispersion BMPs. Rooftops will be routed to Downspout Dispersion Trenches (BMP T5.1013) where applicable. Pollution Generating Impervious Surfaces are managed with Bioretention Cells (BMP T7.30) to expose stormwater to the native soil column to preserve natural infiltration pathways to the broadest application possible. This is the second preferred option for PGHS. The site will also use stormwater mitigation strategies that are not listed within the Stormwater Manual as BMP's. Many of the rooftops will be routed to individual rock detention chambers which provide storage and exposure of stormwater to native soils. This fulfills the intent of MR #5 despite not being a recognized BMP. Stormwater leaving these chambers will then be detained in conventional stormwater systems prior to discharge. Stormwater generated onsite will be managed via LID BMPs under Minimum Requirement#5 to the maximum extent feasible. Stormwater generated from surfaces exceeding the criteria for Runoff Treatment Control (MR#6) and Flow Control (MR #7) will be first directed to On-Site stormwater BMPs and then managed through conventional stormwater techniques. Stormwater leaving the developed sites will comply with all Minimum Requirements to the maximum extent feasible. 1 .2 Project Data Summary Existing and proposed project areas are presented in Table 2 for determination of stormwater management requirements based on prescribed thresholds as outlined in the AMC Section 13.28. Drainage Report Lindsay Project 1 06-Feb-2026 1-1 1.3 Construction Activities The full site is steep and extensive grading will be required. Grading and lots will be configured to blend to the existing topography to the maximum extent feasible in an effort to reduce perimeter walls and provide a more natural aesthetic. Gravel base and asphalt will be imported to create roads, aisles, parking, and driveways. The organic stripping's stockpiled on site will be reused/recycled for soil amendments within vegetated areas. A wetland creation area will also be used for organic soil deposition to eliminate the trucking required to remove these soils. Project disturbance area is 24.44-acres. A separate document titled Stormwater Pollution Prevention Plan for Lindsay Project 1 will detail construction methods for eliminating erosion and sedimentation control. Drainage Report Lindsay Project 1 06-Feb-2026 1-2 Table 1 — Project Location Data Project Data: Applicant Lindsay Investments, LLC. Project Name Lindsay Project 1 Project T.S.R. Location Section 25, 26, Township 31 N, Range 5 W Project Address 8326 172nd St NE, Arlington, WA 98223 Parcel ID(s) 310525-002-006-00, 310526-001-001-00, -002-00, - 022-00, -023-00 Watershed Snohomish, Stillaguamish WRIA number 7, 5 Basin Quilceda Creek, Lower Stillaguamish Sub-Basin Middle Fork Quilceda Creek, Portage Creek Table 2 - Project Theshhold Data Summary Project Data: ........................................................................................................................ Project Name Lindsay Project 1 ......................................................................................................................................................................................................................................................................................................................................................_........................................................................................................................................................... ................................ Existing Conditions: ......................................................................................................................................................................................................................................................................................................................................................_................................................................................................................................................................................... Total Site Area 1,405,371 sf (32.26ac) .................................................................................................................................................................................................................................................._................................................................................................................................................................................... Proposed Activity: Proposed Activity Preliminary Plat Proposed Clearing Area (Total) 1,064,703 sf (24.44 ac) Proposed Grading Area Total 1 064 703 sf 24.44 ac p g (Total) ( ) Allowable New NPGIS (Total) 264,000 sf (6.06 ac) Allowable New PGIS Total 265 941 sf 6.11 ac ( ) ( ) Proposed Replaced Impervious Area 0 sf (0.0000 ac) ......................................................................................................................................................................................................................................................................................................................................................_................................................................................................................................................................................... Native Vegetation convert to Lawn 0 sf (0.0000 ac) Native Vegetation convert to Pasture 0 sf 0.0000 ac g ( ) Total New Impervious Area (Total Allowed) 529,941 sf (12.17 ac) Proposed Disturbance Area 1,064,703 sf (24.44 ac) ......................................................................................................................................................................................................................................................................................................................................................_................................................................................................................................................................................... Project Qualification: ......................................................................................................................................................................................................................................................................................................................................................_................................................................................................................................................................................... Development Type New Development Minimum Requirements 1 thru 9 Drainage Report Lindsay Project 1 06-Feb-2026 1-3 1 .4 Minimum Requirements and Thresholds The project qualifies as new development under Volume I, Chapter 2 of the 2019 DOE Stormwater Management Manual for Western Washington (SMMWW). The SMMWW is specified as the governing document for stormwater management per AMC 13.28.150. This specifies compliance with Minimum Requirements 1-9 of the SMMWW. Lindsay Project 1 requires a full stormwater site plan and compliance with the minimum requirements set forth in the SMMWW. A full construction SWPPP is required. The SWPPP is provided as a separate stand-alone document titled Construction Stormwater Pollution Prevention Plan for Lindsay Project 1 Minimum Requirements 1. Preparation of Stormwater Site Plans 2. Construction Stormwater Pollution Prevention 3. Source Control of Pollution 4. Preservation of Natural Drainage Systems and Outfalls 5. On-site Stormwater Management 6. Runoff Treatment 7. Flow Control 8. Wetlands Protection 9. Operation and Maintenance These are addressed sequentially in this document. Drainage Report Lindsay Project 1 06-Feb-2026 1-4 Section 2 - MR-1 : PREPARE STORMWATER SITE PLAN 2.1 Existing Site Conditions 2.1 .1 Site Location The project is located in Section 25, 26 in Township 31 North, Range 5 West. The site's centroid address is nearest 8326 172nd St NE, Arlington, WA 98223. The site is configured from multiple parcels encompassing the Lindsay Subarea. The location of the site is shown in Figure 1 below. The site is located south of 172nd St NE and west of Highway 9. Access to the site will be from the 172nd St NE Right-of-way. The project is located in the Snohomish and Stillaguamish watershed (WRIA-7 & WRIA-5), in the Quilceda Creek and Portage Creek Sub-Basin's. The majority of the development will be within the Snohomish Watershed. Only a small portion of the site, along the northeast corner, is within the Stillaguamish Watershed (WRIA -5). 2.1 .2 Site Description The site has a total area of 1,405,371-square feet (32.26-acres). The property is zoned Residential Ultra Low Capacity (RULC) and its current use is listed as single-family residences and Vacant. 2.1 .3 Vegetative Cover The development area is pasture with trees scattered throughout the site. Forested areas exist along the southern portions of the subarea. An aerial photo can be seen in Section 11.1 as Figure 2. 2.1 .4 Topography The pre-developed existing topography both onsite and offsite was evaluated using survey drone LiDAR, survey point files, and augmented with DNR LiDAR for areas outside of the project area. The surfaces were combined to create one large conglomerate surface. The average slope as indicated by the LiDAR model is 5.6%throughout the parcel. The site topography is generally moderate to steep with some upland flat areas. Topography is diverse but no significant geological hazard areas exist.The ESNW geotechnical report refers to minor geologically hazardous areas that may be regraded to effectively eliminate any potential risk. (Earth Solutions NW, LLC., 2024) Drainage Report Lindsay Project 1 06-Feb-2026 2-1 2.1 .5 Critical Areas See Critical Areas report and Final Mitigation Plan by Soundview Consultants. (Soundview Consultants, 2025) Existing wetlands and ditches are located throughout the site, likely the result of historic farming in the area. The proposed project intends to excavate a prior farmed and filled area to join two wetlands together that were once likely a singular entity. The wetland creation area will serve to provide upland habitat and hydrology to the headwaters of Quilceda Creek and it's tributaries. An existing conditions map is presented in Figure 2. 2.1 .6 Soils The NRCS Soil mappings for the site consist of Tokul gravelly medial loams. NRCS aerial photography of the soil mappings can be seen in Figure 3. USGS maps indicate the site is underlain by glacial Till soils which are confirmed by onsite soil investigations from ESNW. (Earth Solutions NW, LLC., 2024) Soil log locations are shown in Figure 4. Analysis of the site indicates a large portion of the site as silty sand increasing in density with depth. This is typical of geologic studies of the site which define the site as Quaternary Vashon glacial till. Soil explorations of the area corroborate with the NRCS soil mappings. Groundwater elevation is found to be deep with review of well logs in the vicinity of the site. Stormwater which has percolated through top soil becomes mantled above the impermeable Till layer. This water is referred to as interflow and flows laterally along the underlying topography typically expressing itself at the surface in stream valleys or wetlands. (Minard, 1985) Interflow is seasonal with flow corresponding with the upstream soil thickness and extent whereas groundwater is significant. 2.1 .7 Existing Basin Analysis The project falls within both the Portage Creek Sub-Basin that is a portion of the Stillaguamish Watershed and the Middle Fork Quilceda Creek Sub-Basin that is in the Snohomish Watershed. A high point running from NW to SE separates the two basins. The Portage Creek portion resides in the NE corner of the site and is roughly 4.5 acres. The remaining site is within the Quilceda Creek Basin. It is assumed and highly likely that the entirety of this area is drained through surface runoff and shallow interflow. Very little infiltration will occur through the cemented Till soils. Surface and subsurface flow patterns likely follow the existing topography unless buried stormwater systems exist on site. Agricultural activities have been noted in the past with irrigation and ditching existing in place. The majority of this work appears to be located in the eastern portion of the Linsday Subarea. The project plans to restore some of the hydrology which existed prior to these agricultural efforts. Portage Creek drains to the Stillaguamish River before reaching Puget Sound. There are no known drainage deficiencies or drainage complaints downstream from the project site. Drainage Report Lindsay Project 1 06-Feb-2026 2-2 Stormwater management design is reflective of the discharges to each basin in an effort to maintain natural hydrologic patterns. 2.1 .8 Upstream Analysis There is a significant upstream area to the Subarea site. The upstream areas typically flow through the project site channelized within one of the streams or drainages which flow from the southeast to the northeast. This flow reaches Edgecomb/Quilceda Creek at the northwest corner of the subarea at 172nd St. Upstream runoff that reaches the project site not already in a channelized corridor is minimal and in a dispersed state. This flow may only exist along the eastern boundary line and will be capture and discharged in its natural state. The southern boundary may have intermittent dispersed flows enter into the site. An existing driveway along the southern boundary captures most of this flow and channelizes it into culverts which convey to creeks and drainages north of this existing gravel drive. All upstream contribution to the site should be collected, managed, and discharged following the requirements of Minimum Requirement#4- Preservation of natural drainage pathways. 2.1 .9 Existing Drainage The site topography trends northward. Due to the presence of "C" type soils, surface runoff is expected to occur. There is considerable ditching and land alteration of the existing sites which have altered the natural drainage patterns and courses. The project intends to restore the natural drainage pathways through dispersion without causing flooding or downstream erosion problems. 2.1 .10 Downstream Analysis Stormwater developed onsite will follow the existing drainage channels and streams. Nearly all stormwater generated onsite will be discharged to the streams and channels due to the onsite Till soils which prevents or retards infiltration. The majority of the site stormwater will leave the subarea in the northwest corner. A small portion of the site will discharge to the northeast corner within a different drainage basin. Northwest Downstream Route (Quilceda Creek Basin) Stormwater discharged within the western portion of the site leaves the site within Edgecomb Creek at the northwest corner of the site. Edgecomb Creek parallels 172nd St to the 67th Ave intersection where it passes beneath 67th through a 60-inch diameter culvert. Flow continues traveling west before crossing beneath the railroad through a 24-inch diameter culvert. The railroad crossing is 2,600 feet from the project site. Edgecombe Creek flows through a rechanneled stream corridor following 67th Ave before merging with Quilceda Creek. Northeast Downstream Route (Portage Creek Basin) Stormwater leaves the Northeast corner of the project site alongside 172nd St NE. Stormwater flows through a neighboring 12-inch driveway culvert and roughly 150 feet of open ditch before reaching a 30-inch culvert that flows north beneath 172nd St. Water then flows beneath 172nd PI NE through an arch culvert before continuing northwest. Flows continue through wetlands and vegetated areas Drainage Report Lindsay Project 1 06-Feb-2026 2-3 for 1,300 feet before reaching an existing pond at 178th PI NE. Water continues to the northwest through the Glen Eagle residential development. There are no known flooding or erosion concerns adjacent to the site. Drainage Report Lindsay Project 1 06-Feb-2026 2-4 Section 3 — MR-2: Stormwater Pollution Prevention Plan 3.1 Storm Water Pollution Prevention Plan A Storm Water Pollution Prevention Plan (SWPPP) has been prepared for this project and presented as a separate document titled "Stormwater Pollution Prevention Plan for Lindsay Project 1", 6-Feb-2026 Drainage Report Lindsay Project 1 06-Feb-2026 3-1 Section 4 - MR-3: Source Control of Pollution The 2019 SMWW Volumed, Ch-2.5.3 require source control BMPs for all development projects for the intended purpose to prevent stormwater from coming in contact with pollutants. The activities and the associated source control BMPs are listed in Volume-IV of the manual. These are primarily commercial industrial developments that involve significant pollutant generation potential. The proposed stormwater facilities addressed in this report manage stormwater generated from passenger vehicle parking, driveways, roads and non-pollution generating rooftop. No source control BMPs apply to these facilities controlling stormwater from these surfaces. No Volume-IV source control BMPs are specified. For construction activities, source control BMPs prescribed in Volume-II are specified and described in the construction SWPPP per MR#2. Drainage Report Lindsay Project 1 06-Feb-2026 4-1 Section 5 - MR-4: Preserve Natural Drainage Systems and Outfalls All drainage courses are to be preserved to the maximum extent feasible. All outfalls will remain in their current locations. Natural drainage patterns as they once existed shall be retained. Pre- developed conditions experience a sheet flow drainage pattern to the northwest and northeast. The developed site is designed to disperse flows to maintain the existing pattern to the west and east. Stormwater in the eastern portion of the site will be managed through Full Dispersion by excavating and recreating the existing natural hydrology and wetland hydrology that existed before the agricultural drainage systems were installed. Wetlands will be hydrated to the maximum extent feasible while meeting the stream protection duration requirements. Stormwater is intended to be dispersed along the perimeter of all critical area buffers to the maximum extent feasible to replenish natural hydrology through the soil column. Level spreader dispersion trenches will deposit stormwater to the natural soil column allowing water to diffuse below ground. Higher flows will express stormwater across the surface. The combination of implemented BMP controls for stormwater generated from the development will mimic the natural stormwater routes and mechanisms though all known, available, and reasonable methods of control and treatment. (Full Dispersion, Bioretention, Downspout Dispersion, etc.) Conventional detention systems will discharge to the native corridors with level spreaders. Drainage Report Lindsay Project 1 06-Feb-2026 5-1 Section 6 - MR-5: On-site Stormwater Management Minimum Requirement#5 specifies requirements for on-site stormwater BMPs. This requirement mandates that on-site stormwater runoff be infiltrated, dispersed, and/or retained to the maximum extent feasible without causing flooding or erosion impacts. Projects triggering Minimum Requirements 1 through 5 must use On-site stormwater management BMPs from List#1 for all surfaces or demonstrate compliance with the LID Performance Standard. Projects triggering Minimum Requirements 1 through 9 must meet the requirements of Table 2.5.1 in Vol. 1 of the 2019 SMMWW. Table 2.5.1 specifies the requirements for new or redevelopment depending on UGA and parcel size to meet the requirements of the LID Performance Standard and/or List#2. List #1 and List#2 specify stormwater BMPs in order of preference. The first BMP determined feasible is required. This project triggers MR's 1-9 for the Preliminary Plat Submittal of Project 1. This project is within the City's UGA. This project is required to adhere to the LID Performance Standard or List #2 per Table 2.5.1. List#1 and #2 contain appropriate BMPs to mitigate a particular developed surface. The surfaces included in the list are Lawn and Landscaped Areas, Roofs, and other hard (impervious) surfaces (road/driveway/parking). Lawn/Landscape is required to utilize BMP T5.13, Post-Construction Soil Quality and Depth. Roofs are required to employ BMP T5.30 Full Dispersion or Downspout Infiltration, Rain Gardens or Bioretention, BMP T5.10A Downspout Dispersion Systems, or perforated stub- out connections. The first feasible BMP in this list must be used. Other Hard surfaces (Roads, Driveways, Parking Lots, Etc.) must utilize BMP T5.30 Full Dispersion, BMP T5.15 Permeable Pavement, Bioretention, Sheet Flow Dispersion, or Concentrated Flow Dispersion. The first feasible BMP in this list must be used. All lawn/landscape and native vegetation rehydration areas will meet the requirements of BMP T5.13. In some limited cases, roofs adjacent to the stream buffer will be able to provide BMP T5.30 Full Dispersion. Full Dispersion requires 100 foot flow paths within native areas on slopes which do not exceed 15%. The east portion of the site will be topographically modified to provide flow paths meeting this requirement through areas replanted with native vegetation. A recreated wetland area will be provided downstream from the full dispersion and serve to rehydrate the surrounding wetlands that have been altered during farming. Rooftops adjacent to buffers and native areas may be dispersed through the application of BMP T5.1013 to the maximum extent feasible. Steep slopes may preclude their installations in some scenarios. Areas subject to flow control may be required to convey rooftops to detention facilities. These rooftops will be connected to the conveyance system through gravel detention systems that closely mimic the perforated stub-out connections BMP T5.10C, except they are intended to detain stormwater on each individual lot. The intent of the perforated stub-out connection is to allow stormwater as many chances as possible to be reintroduced to the native soil column and replenish Drainage Report Lindsay Project 1 06-Feb-2026 6-1 natural hydrologic pathways. The rock detention chamber will mimic this intent will also providing detention. Rooftops will be managed following the indented feasibility list above. Driveways, roadways, and sidewalk surfaces for the development site are predominately managed through bioretention cells. There will be a small area in the east which manages the roads and driveways through Full Dispersion. Permeable Pavement will not feasible due to the consolidated nature of Till soils which preclude infiltration. Driveway Sheet flow dispersion, BMP T5.12, will also not be feasible due to the urban road section requirements. In areas of the site adjacent to native vegetation with flow paths exceeding 50 feet and slopes less than 15%, this BMP may be applied. There are very few locations where this may be acceptable and project site specific proposals will need to identify these areas. Full Dispersion requires native open space to be retained at a ratio of 65 to 10. The project will be able to maintain the 65:10 open space to impervious surface ratio within the portion of the site defined as Full Dispersion. Not all urban developments are capable of achieving Full Dispersion. Unfortunately, the entire site cannot be accommodated with Full Dispersion but as much of the site will be managed with this primary preferred method as possible. Bioretention used to meet MR #5 is designed in accordance with BMP T7.30 per Page 7-3 of Vol. V of the 2019 SMMWW. Stormwater is released to the bioretention cells through sheet flow or a bubble-up conveyance system. The bubble-up system is designed to reduce erosion of the bioretention soil media at the surface of the cell. A site plan showing the stormwater management and development can be seen in Figure 4. Drainage Report Lindsay Project 1 06-Feb-2026 6-2 Section 7 - MR-6: Runoff Treatment Minimum Requirement#6 specifies the requirements for providing runoff treatment. The threshold for requiring a treatment BMP is 5,000 square feet of PGIS (Pollution Generating Impervious Surface) or a total of more than % of an acre of PGPS (Pollution Generating Pervious Surface). This project is expected to generate 265,941 square feet(6.11 acres) of PGIS based on road and driveway areas, therefore treatment facility BMPs are required for this project. Runoff treatment facility selection is outlined in Vol. I, Ch. 4.2, Step V of the 2019 SMMWW. Step V outlines the treatment facility selection flow chart based on the intended use of a project. Treatment selection is based on if the site is a high-use site, if the downstream receiving waters are phosphorous sensitive, and/or if the site is required to provide enhanced treatment. The definitions of high-use, phosphorous control, and enhanced treatment can be found in Step V in Section 4.2 of the 2019 SMMWW. The project is not a high use site. The project is not required to treat for phosphorous. Enhanced treatment is not required for the project. Basic treatment is required per Vol. I, Ch. 2 &4 of the 2019 SMMWW. Enhanced and Basic treatment is provided through the use of bioretention facilities per Vol. III Section 3.3.12 of the 2019 SMMWW. The bioretention specified will provide the additional enhanced treatment of stormwater influent. The bio-cell treats stormwater through the infiltration of stormwater through soils and their ability to absorb pollutants. Soils have a CEC of greater than 5 meg/100g to a depth of 12 inches. On-site soils are suitable for use. See Vol III. Section 3.3.12 of the 2019 SMMWW for specific soil design criteria. Road, Driveway, and Parking Area The project has PGIS areas exceeding the threshold for simple treatment BMPs. Therefore, the development is required to employ treatment for its respective road, driveway, and parking areas. The project utilizes bio-retention cells for treatment. The bio-cell mitigates polluted stormwater through physical, chemical, and biological treatment processes. The treatment process reduces pollutant loads to downstream receiving waters. Pretreatment (flow entrance and presettling) is handled by the 5/8" clean chip rock filter that is adjacent the edge of asphalt along its entire length or through bubble-up structures at point conveyances. Stormwater then percolates through compost amended soils and plantings to obtain treatment. Stormwater flows through this part of the cell at a rate of 12.0 inches/hour. Stormwater that has passed through the engineered soil media will be stored within a rock layer beneath the cell. The total percolated runoff through the bio-cell's amended soils is well over the 91%total runoff volume treatment requirement, with a combined efficiency of 95%. See Section Error! Reference source not found.. Drainage Report Lindsay Project 1 06-Feb-2026 7-1 Section 8 - MR-7: Flow Control 8.1 Flow Control Minimum Requirement#7 specifies the requirements for runoff flow control. The threshold for requiring Minimum Requirement#7 is 5,000 square feet of impervious surface. Flow control shall be provided if the project creates more than 10,000 square feet of effective impervious area in a threshold discharge area, converts % of an acre or more of native vegetation to lawn, 2.5 acres or more native vegetation is converted to pasture, or a combination of impervious and converted pervious surfaces cause a 0.1 cfs increase in the 100-year flow frequency from a continuous simulation runoff model. The project exceeds this requirement and is required to provide flow control. All runoff from impervious surfaces and converted surfaces must be infiltrated if feasible. If determined infeasible standard flow control will govern. Standard flow control requires that stormwater discharges match pre-developed discharge durations for the range of pre-developed discharge rates from 50% of the 2-year peak flow to the 50-year peak flow. The pre-developed condition shall be matched to the fully-forested condition (soils and vegetation) to which the Western Washington Hydrologic Model (WWHM) is calibrated, unless reasonable, historic information is provided that indicates the site was prairie prior to Euro-American settlement. This requirement may also be met by dispersion and infiltration. Rooftop, driveway, and roadway that are managed with BMP T5.30 Full Dispersion are discounted from the model. Full Dispersion of surfaces only occur in the SE portion of the site and drain to the wetland creation area through 100-ft flow paths consisting of native vegetation. Outside of the Full Dispersion area, the site stormwater management practices combine traditional detention and bio-retention for the remaining surfaces. The project uses bioretention cells to manage and treat all incoming impervious surface generated stormwater (PGIS and NPGIS). The bioretention cells consist of 1.5 feet of amended soils, 0.5 feet of filter, and varying thicknesses of rock. The bioretention cells detain stormwater before releasing to the downstream trunk lines. There are four basin's located on site, each with independent flow control assessment. Each comprises of bioretention cell and detention vault to meet the necessary flow control requirement of each area. Lots within the West basin area will discharge to an individual lot rock detention chamber. These stormwater systems are orifice controlled with a 0.25" orifice to meter stormwater draining directly from the homes rooftop. These are then collected in a lot drain trunk line and metered flows are directed to the detention vault for final storage and discharge. See Figure 5 for basin map of contributing stormwater areas to proposed facilities. Hydrologic Analysis was conducted using the latest version of the WWHM software. Software reports are in Section Error! Reference source not found.. Supplementary information for the continuous simulation models is presented in Section 12.4. A site plan showing the location of bioretention swale can be seen in Section 11.1. Drainage Report Lindsay Project 1 06-Feb-2026 8-1 Section 9 - MR-8: Wetlands Protection AMC 13.28.150 (MR 8) specifies requirements for detention or treatment in wetlands and wetland buffers as well as discharge of stormwater to a stream or wetland. Minimum Requirement #8 requires that stormwater discharges to wetlands within a projects TDA shall meet a specified Level of Wetland Protection. There are four Wetland Protection Levels that apply to the TDA: General Protection, Protection from Pollutants, Wetland Hydroperiod protection Method 1, and Method 2. Both General Protection and Protection from Pollutants wetland protection levels are satisfied with the proper implementation of Minimum Requirement #2 and Minimum Requirement #5 & #6, respectively. Wetland Hydroperiod Protection Methods require monitoring of wetland discharges to maintain existing wetland input volumes. The wetland input volume is a different analysis than the flow rate control of the Stream Protection Duration requirement of Minimum Requirement #7. Minimum Requirement #8 does take precedence over satisfying Minimum Requirement #7. (See Vol. I, Ch.3, Section 3.4.8 of the SMMWW) However, none of the wetlands on-site or downstream meet the criteria of Method 1 or Method 2 for discharges. Therefore, MR#8 is satisfied with the implementation of General Protection and Protection from Pollutants criteria. Drainage Report Lindsay Project 1 06-Feb-2026 9-2 Section 10 - MR-9: Operation and Maintenance Minimum Requirement#9 contains requirements for inspection, operation and maintenance of stormwater facilities and BMPs. Specific maintenance standards and requirements are outlined in Volume V of the 2019 SMMWW. The 2019 SMMWW requires the regular maintenance and inspection of drainage facilities. The Operations and Maintenance manual will be supplied with Construction Plans for this project and presented as a separate document titled "Operations and Maintenance manual for Lindsay Project 1", 6-Feb-2026. Drainage Report Lindsay Project 1 06-Feb-2026 10-1 Section 11 - Support Data 11.1 Maps & Figures KEY Master Planned Area (r/tnl IrlrrrinA f eo, s Sub-Area Fending Project Area i _ •; QFuture Development Area < n z #a# �i Sf m 1E Master Plan 172 Sr.NE Sub-Area Boundary I- , ' Future � i Pending Development Project Ili '6 N��� \ St"mish Cwnry\ VICINITY MAP SCALE I"=IOW Figure 1 - Vicinity Map Drainage Report Lindsay Project 1 06-Feb-2026 11-1 7"WOF a. �A � } Al �" •��.. -� - i k� ��i• ` ,r t 'gym .�h,r� _��' � ;'�,.. - k � Figure 2 - Existing Conditions -11 - ' Awma;A t i v e 3 ti o • a 1 ,. Figure 3 - NRCS Soil Map (Not to Scale) Drainage Report Lindsay Project 1 06-Feb-2026 11-2 Individual Lot Rock Detention NE Detention 172nd SINE = Chamber(typ) Vault ----FP 1 FIr F I It I - - Level Bio-etentlon Spreader T I Outfall / i _ It B or t nt o Bioretention : i r i i West Detentio ff r i r i i r i Vault Single Family �r.I esidences Swale Level r/ Spreader I // Outfall Southwest Storm ` Full Detention Chamber Dispe ion Area I Full er io Area Existing \ Forested Di rsion Area Ditch ! L Wetland Creation Area to connect existing wetlands and restore wetland/stream ! hydrology 0 0 409 800 Scale: 1"=400' Figure 4 - Site Plan Drainage Report Lindsay Project 1 06-Feb-2026 11-3 J ij N7Detenti N BasiWest asin- v I I` J � I �I West Weft t io'eleTion Cell Deter ti n Roofs conveyed L- ------ LLB It to individual rock - chamber(typ) Out vv n M- SW ZB,,reten ion II lr� Southwest Gr el j Detention Chamb NE Upstream ersion Wetland Area - Creation Area Upstream Basin 0 0 200' 400' a Scale: 1"=200' Figure 5 - Stormwater Basin Map for Proposed Facilities Drainage Report Lindsay Project 1 06-Feb-2026 11-4 � I _ jljl Snohomish Stillaguamis - A-7 WRIA 5 i FFPredeveloped .02acres 4.02 acres 174,999 sf West-NW Predeveloped Rat 7.79 acres North East I. 339,475 sf �� Predeveloped Rat 4.53 acres 197,5011 1 .Sfi//aguxmi�h WRIA-S SouTh West -- Sn©ho 9.24 acres n7ish 402,278 sf C).jRIA_7 rl �... SouthWe Predevelpp SoulhWert Offsite Rqqt Predevelopec not .93 ocre3. 1.86 acres 81,108 sf SouthWest Predeveloped Offslte Rat 1.76 acres \ r Q 0 300' 600' Scale: 1"=300' Figure 6 — Existing PreDeveloped Basin Map Drainage Report Lindsay Project 1 06-Feb-2026 11-5 Section 12 Support Data This appendix contains the following support data as applicable to this report: • Soils Data • Reference Documents • Topographic Data • Continuous Simulation Modeling • Software Output Drainage Report Lindsay Project 1 06-Feb-2026 12-6 12.1 Soils The following data was extracted from Web Soil Survey, National Cooperative Soil Survey: Table 3 - Soil Table 17—Everett very gravelly sandy loam, 0 to 8 percent slopes Map Unit Setting National map unit symbol.2t629 Elevation: 30 to 900 feet Mean annual precipitation: 35 to 91 inches Mean annual air temperature:48 to 52 degrees F Frost-free period: 180 to 240 days Farmland classification: Farmland of statewide importance Map Unit Composition Everett and similar soils:80 percent Minor components:20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Everett Setting Landform: Eskers, moraines, kames Landform position (two-dimensional): Summit, shoulder Landform position (three-dimensional):Crest, interfluve Down-slope shape: Convex Across-slope shape:Convex Parent material: Sandy and gravelly glacial outwash Typical profile Oi- 0 to 1 inches:slightly decomposed plant material A - 1 to 3 inches:very gravelly sandy loam Bw- 3 to 24 inches:very gravelly sandy loam C1 -24 to 35 inches:very gravelly loamy sand C2-35 to 60 inches:extremely cobbly coarse sand Properties and qualities Slope: 0 to 8 percent Depth to restrictive feature: More than 80 inches Natural drainage class:Somewhat excessively drained Capacity of the most limiting layer to transmit water(Ksat): High (1.98 to 5.95 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Low (about 3.2 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated):4s Hydrologic Soil Group:A Forage suitability group: Droughty Soils (G002XN402WA), Droughty Soils (G002XF403WA), Droughty Soils (G002XS401 WA) Hydric soil rating: No 39—Norma loam Map Unit Setting National map unit symbol:2hyx Elevation:0 to 1,000 feet Mean annual precipitation: 35 to 60 inches Mean annual air temperature:48 to 52 degrees F Drainage Report Lindsay Project 1 06-Feb-2026 12-7 Frost-free period: 150 to 200 days Farmland classification: Prime farmland if drained Map Unit Composition Norma, undrained, and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Norma, Undrained Setting Landform: Depressions, drainageways Parent material:Alluvium Typical profile H1 - 0 to 10 inches:ashy loam H2- 10 to 28 inches:sandy loam H3-28 to 60 inches:sandy loam Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Poorly drained Capacity of the most limiting layer to transmit water(Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table:About 0 inches Frequency of flooding: None Frequency of ponding: Frequent Available water storage in profile: Moderate (about 9.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 5w Hydrologic Soil Group: B/D Forage suitability group 74—Tokul gravelly medial loam, 15 to 30 percent slopes Map Unit Setting National map unit symbol:2t61 m Elevation: 160 to 1,640 feet Mean annual precipitation:45 to 70 inches Mean annual air temperature:46 to 52 degrees F Frost-free period: 140 to 200 days Farmland classification: Farmland of statewide importance Map Unit Composition Tokul and similar soils:70 percent Minor components:30 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Tokul Setting Landform: Hillslopes, till plains Landform position (two-dimensional). Footslope Landform position (three-dimensional): Side slope, tread Down-slope shape: Convex Across-slope shape:Convex Parent material:Volcanic ash mixed with loess over glacial till Typical profile Oi- 0 to 1 inches:slightly decomposed plant material Oa - 1 to 2 inches: highly decomposed plant material A - 2 to 6 inches:gravelly medial loam Bs1 - 6 to 9 inches:gravelly medial loam Bs2- 9 to 17 inches:gravelly medial loam Bs3- 17 to 24 inches:gravelly medial loam Drainage Report Lindsay Project 1 06-Feb-2026 12-8 BC- 24 to 33 inches: gravelly medial fine sandy loam 2Bsm-33 to 62 inches:cemented material Properties and qualities Slope: 15 to 30 percent Depth to restrictive feature: 20 to 39 inches to cemented horizon; 20 to 39 inches to densic material Natural drainage class: Moderately well drained Capacity of the most limiting layer to transmit water(Ksat):Very low to moderately low (0.00 to 0.06 in/hr) Depth to water table:About 18 to 36 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 8.7 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated):4e Hydrologic Soil Group: B Forage suitability group: Limited Depth Soils (G002XF303WA), Unnamed (G002XN303WA) Hydric soil rating: No 77—Tokul-Winston gravelly loams, 25 to 65 percent slopes Map Unit Setting National map unit symbol:2j08 Elevation: 150 to 1,900 feet Mean annual precipitation:40 to 80 inches Mean annual air temperature:46 to 50 degrees F Frost-free period: 140 to 200 days Farmland classification: Not prime farmland Map Unit Composition Tokul and similar soils:60 percent Winston and similar soils: 30 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Tokul Setting Landform:Till plains, escarpments Parent material:Volcanic ash over basal till Typical profile H1 - 0 to 4 inches: gravelly medial loam H2-4 to 22 inches:gravelly medial loam H3-22 to 31 inches:gravelly medial fine sandy loam H4-31 to 60 inches:gravelly sandy loam Properties and qualities Slope:25 to 65 percent Depth to restrictive feature:20 to 40 inches to densic material Natural drainage class: Moderately well drained Capacity of the most limiting layer to transmit water(Ksat):Very low to moderately low (0.00 to 0.06 in/hr) Depth to water table:About 18 to 36 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Low (about 5.8 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7e Hydrologic Soil Group: C Hydric soil rating: No Description of Winston Setting Landform: Escarpments Drainage Report Lindsay Project 1 06-Feb-2026 12-9 Parent material:Volcanic ash and glacial outwash Typical profile H1 - 0 to 3 inches: gravelly ashy loam H2-3 to 25 inches:gravelly fine sandy loam H3-25 to 60 inches:extremely gravelly coarse sand Properties and qualities Slope: 25 to 65 percent Depth to restrictive feature: 20 to 40 inches to strongly contrasting textural stratification Natural drainage class:Somewhat excessively drained Capacity of the most limiting layer to transmit water(Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Moderate (about 7.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7e Hydrologic Soil Group: B Hydric soil rating: No Data Source Information Natural Resources Conservation Service Web Soil Survey, National Cooperative Soil Survey 7/23/2014 Soil Survey Area: Arlington, Washington (Snohomish County) Drainage Report Lindsay Project 1 06-Feb-2026 12-10 12.2 Reference Documents Cobalt Geosciences, LLC. (2022). Geotechnical Evaluation Proposed Development Parcel No.31051400101800. Kenmore: Haberman, Philip A. Cobalt Geosciences, LLC. (2023). Groundwater Elevations. Kenmore. Earth Solutions NW, LLC. (2024). Geotechincal Engineering Study Lindsay Annexation. Redmond. Minard, J. (1985). Geologic Map of the Arlington East Quadrangle, Snohomish County, Washington. USGS. Sewall, E. (2022). Lot 19- Revised Critical Area Report. Sewall Wetland Consulting, Inc. Soundview Consultants. (2025). Conceptual Mitigation Plan - Lindsay Annexation. Gig Harbor: Soundview Consultants. 12.3 Topographic Data • Snohomish County 2005 LiDAR survey was used to augment the existing site topography and the downstream and surrounding areas. Citation: LiDAR Bare Earth DEM Files: be_48122b22.zip. Available: Puget Sound LiDAR Consortium, Seattle, WA • Modeled coordinate system: Lateral - Washington State Plan Plane - North, FIPS 4601; Vertical — NAVD 88 Drainage Report Lindsay Project 1 06-Feb-2026 12-11 12.4 Continuous Simulation Modeling 12.4.1 Continuous Simulation Background HSPF based continuous simulation modeling was used to evaluate the hydrologic performances of the pre-developed and developed sub-basins in order to accurately assess flow rates. The currently adopted continuous simulation models use the HSPF (Hydraulic Simulation Program in FORTRAN) software engine. The HSPF model uses a robust and detail accounting of the 'water budget', including evaporation, evapotranspiration, interception, interflow, and groundwater. The modeling accounts for and assesses land segment areas that include vegetation or impervious cover, soil types, and slopes. The modeling also utilizes over 50 years of continuous rainfall data (precipitation) and evaporation data for the area. The HSPF continuous modeling is considered the best available science for hydrologic analysis. 12.5 Modeling Methodology HSPF modeling was managed via the Western Washington Hydrology Model (WWHM) interface program. The current professional version of WWHM by Clearcreek Solutions, Inc., WWHM-2012 was used. The current data precipitation and evaporation set provided by DOE with the WWHM- 2012 software interface was used that includes quantized data in 15-minute time steps from October 1948 to October 2009. The WWHM program comes packaged with generic, well considered HSPF modeling parameters. These settings allow for the modeling of the majority of the topological conditions found in the Puget Sound area. Where conditions fall reasonably outside the range of the default HSPF parameters, adjustments should be made to more accurately reflect those conditions. These is generally limited to the pervious land segments (IMPLNDS) and are mostly limited to slopes (SLSUR), infiltration rates (INFILT), and length of flow path (LSUR). For this project, HSPF parameters were not adjusted to reflect site conditions. 12.5.1 Existing Conditions The surface vegetative cover is assumed forested with steep slope. The NRCS soil maps indicate A,B,D soils throughout the project area. For hydrologic modeling, C-type soils are used as the site is mapped by USGS to be Advance outwash with the upstream basin primarily mapped as C, Till. Both of these geologic units have been glacially consolidated. Consolidated soils are mapped as C-type soils. Outside of the disturbance area, there is no land conversion. Drainage Report Lindsay Project 1 06-Feb-2026 12-12 12.5.2 Developed Conditions The site is steep and grading will consist of stripping existing soils and importing some structural soils to establish building pads. All areas are accounted for and used in the WHMM program except for the Areas dispersed with Full Dispersion (Rooftop, Driveway, parking, road, and remaining percentage of associated yards areas). The remaining area of the site is used for stormwater management. Three difference basins exist within the remaining site area. The west basin has a combination of detention vault and individual lot rock detention chambers. Road and Driveway runoff are captured by the bioretention cells before draining to the vault. Stormwater in the southwest portion of the site is directly to a series of bioretention cells before final storage in a rock detention chamber. The rock detention chamber detains stormwater before release to the downstream drainage pathway. The northeast basin collects stormwater from rooftops in conveyance swale or pipe conveyance system before discharging to the detention vault. The road and driveway areas within the NE Basin collect stormwater in a bioretention cell utilized for water quality treatment only before filtered stormwater is released to the detention vault. The NE basin discharges to the east and is within a separate watershed then the rest of the site. A portion of the upstream offsite flow is inevitably cut-off from the western basin. This area is brought to the northeast and site grading has been reorganized to ensure equilibrium of areas flowing to each watershed. The stormwater bio-retention cells will be excavated down below the sealed surface layer to expose stormwater to the native soil profile. The exposure of stormwater to the native soil reintroduces natural hydrology to the site and surrounding/downstream areas. This is key to the preservation of late-summer stream flows in head-water type sites in our region. The bio-cell areas are accounted for in the WWHM bio-retention element and are therefore discounted from the basin area. Drainage Report Lindsay Project 1 06-Feb-2026 12-13 Section 13 - Software Output The following WWHM reports in this section represent individual sub-basin analysis for hydrologic flow evaluations. The following heading is common to all reports. The West Basin uses a Time Series element which is a combination of the 79 lots draining to the individual lot rock detention systems. Drainage Report Lindsay Project 1 06-Feb-2026 13-14 13.1 West Basin WWHM2012 PROJECT REPORT Project Name: West WSDOT AV wIndRck Swale3 2025UPDT Site Name: Lindsay Annexation Site Address: 172nd St NE City : Arlington Report Date: 12/3/2025 MGS Regoin Puget East Data Start 1901/10/1 Data End : 2058/09/30 DOT Data Number: 05 Version Date: 2025/05/13 Version : 4 .3.2 Low Flow Threshold for POC 1 50 Percent of the 2 Year High Flow Threshold for POC 1: 50 year PREDEVELOPED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat 8.493 C, Forest, Steep 4.317 Pervious Total 12.81 Impervious Land Use acre Impervious Total 0 Basin Total 12.81 Element Flows To: Surface Interflow Groundwater MITIGATED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 1.89 Drainage Report Lindsay Project 1 06-Feb-2026 13-15 DRIVEWAYS FLAT 0.85 SIDEWALKS FLAT 0.49 Impervious Total 3.23 Basin Total 3.23 Element Flows To: Surface Interflow Groundwater Surface retention 1 Surface retention 1 Name Vault 1 Width 77 ft. Length 100 ft. Depth: 9 ft. Discharge Structure Riser Height: 8 ft. Riser Diameter: 12 in. Notch Type : V-notch Notch Angle: 0.500 Notch Height: 4 .000 ft. Orifice 1 Diameter: 1.669 in. Elevation: 0 ft. Orifice 2 Diameter: 0.745 in. Elevation: 3.95 ft. Orifice 3 Diameter: 1 in. Elevation: 5.5 ft. Element Flows To: Outlet 1 Outlet 2 Vault Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.176 0.000 0.000 0.000 0.1000 0.176 0.017 0.023 0.000 0.2000 0.176 0.035 0.033 0.000 0.3000 0.176 0.053 0.041 0.000 0.4000 0.176 0.070 0.047 0.000 0.5000 0.176 0.088 0.053 0.000 0.6000 0.176 0.106 0.058 0.000 0.7000 0.176 0.123 0.063 0.000 0.8000 0.176 0.141 0.067 0.000 0.9000 0.176 0.159 0.071 0.000 1.0000 0.176 0.176 0.075 0.000 1.1000 0.176 0.194 0.079 0.000 1.2000 0.176 0.212 0.082 0.000 1.3000 0.176 0.229 0.086 0.000 1.4000 0.176 0.247 0.089 0.000 1.5000 0.176 0.265 0.092 0.000 1.6000 0.176 0.282 0.095 0.000 1.7000 0.176 0.300 0.098 0.000 1.8000 0.176 0.318 0.101 0.000 1.9000 0.176 0.335 0.104 0.000 2.0000 0.176 0.353 0.106 0.000 2.1000 0.176 0.371 0.109 0.000 2.2000 0.176 0.388 0.112 0.000 2.3000 0.176 0.406 0.114 0.000 2.4000 0.176 0.424 0.117 0.000 2.5000 0.176 0.441 0.119 0.000 2.6000 0.176 0.459 0.121 0.000 Drainage Report Lindsay Project 1 06-Feb-2026 13-16 2.7000 0.176 0.477 0.124 0.000 2.8000 0.176 0.494 0.126 0.000 2.9000 0.176 0.512 0.128 0.000 3.0000 0.176 0.530 0.130 0.000 3.1000 0.176 0.548 0.133 0.000 3.2000 0.176 0.565 0.135 0.000 3.3000 0.176 0.583 0.137 0.000 3.4000 0.176 0.601 0.139 0.000 3.5000 0.176 0.618 0.141 0.000 3.6000 0.176 0.636 0.143 0.000 3.7000 0.176 0.654 0.145 0.000 3.8000 0.176 0.671 0.147 0.000 3.9000 0.176 0.689 0.149 0.000 4.0000 0.176 0.707 0.154 0.000 4.1000 0.176 0.724 0.158 0.000 4.2000 0.176 0.742 0.162 0.000 4.3000 0.176 0.760 0.166 0.000 4.4000 0.176 0.777 0.169 0.000 4.5000 0.176 0.795 0.173 0.000 4.6000 0.176 0.813 0.177 0.000 4.7000 0.176 0.830 0.181 0.000 4.8000 0.176 0.848 0.186 0.000 4.9000 0.176 0.866 0.190 0.000 5.0000 0.176 0.883 0.195 0.000 5.1000 0.176 0.901 0.201 0.000 5.2000 0.176 0.919 0.206 0.000 5.3000 0.176 0.936 0.213 0.000 5.4000 0.176 0.954 0.219 0.000 5.5000 0.176 0.972 0.226 0.000 5.6000 0.176 0.989 0.242 0.000 5.7000 0.176 1.007 0.254 0.000 5.8000 0.176 1.025 0.265 0.000 5.9000 0.176 1.042 0.277 0.000 6.0000 0.176 1.060 0.288 0.000 6.1000 0.176 1.078 0.300 0.000 6.2000 0.176 1.096 0.312 0.000 6.3000 0.176 1.113 0.325 0.000 6.4000 0.176 1.131 0.339 0.000 6.5000 0.176 1.149 0.352 0.000 6.6000 0.176 1.166 0.367 0.000 6.7000 0.176 1.184 0.382 0.000 6.8000 0.176 1.202 0.397 0.000 6.9000 0.176 1.219 0.413 0.000 7.0000 0.176 1.237 0.430 0.000 7.1000 0.176 1.255 0.448 0.000 7.2000 0.176 1.272 0.466 0.000 7.3000 0.176 1.290 0.485 0.000 7.4000 0.176 1.308 0.504 0.000 7.5000 0.176 1.325 0.524 0.000 7.6000 0.176 1.343 0.545 0.000 7.7000 0.176 1.361 0.567 0.000 7.8000 0.176 1.378 0.589 0.000 7.9000 0.176 1.396 0.612 0.000 8.0000 0.176 1.414 0.636 0.000 8.1000 0.176 1.431 0.972 0.000 8.2000 0.176 1.449 1.549 0.000 8.3000 0.176 1.467 2.154 0.000 8.4000 0.176 1.484 2.606 0.000 Drainage Report Lindsay Project 1 06-Feb-2026 13-17 8.5000 0.176 1.502 2.852 0.000 8.6000 0.176 1.520 3.091 0.000 8.7000 0.176 1.537 3.289 0.000 8.8000 0.176 1.555 3.473 0.000 8.9000 0.176 1.573 3.646 0.000 9.0000 0.176 1.590 3.810 0.000 9.1000 0.176 1.608 3.966 0.000 9.2000 0.000 0.000 4.116 0.000 Name Bioretention 1 Bottom Length: 70.00 ft. Bottom Width: 40.00 ft. Material thickness of first layer: 1.5 Material type for first layer: SMMWW 12 in/hr Material thickness of second layer: 0.5 Material type for second layer: Sand Material thickness of third layer: 0.5 Material type for third layer: GRAVEL Underdrain used Underdrain Diameter (feet) : 0.5 Orifice Diameter (in. ) : 3 Offset (in. ) : 0 Flow Through Underdrain (ac-ft. ) : 1567.75 Total Outflow (ac-ft. ) : 1603.043 Percent Through Underdrain: 97.8 Discharge Structure Riser Height: 1 ft. Riser Diameter: 12 in. Notch Type: Rectangular Notch Width: 0.250 ft. Notch Height: 0.160 ft. Element Flows To: Outlet 1 Outlet 2 Vault 1 Bioretention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.0643 0.0000 0.0000 0.0000 0.0440 0.0643 0.0013 0.0000 0.0000 0.0879 0.0643 0.0026 0.0000 0.0000 0.1319 0.0643 0.0039 0.0000 0.0000 0.1758 0.0643 0.0052 0.0000 0.0000 0.2198 0.0643 0.0065 0.0000 0.0000 0.2637 0.0643 0.0078 0.0000 0.0000 0.3077 0.0643 0.0090 0.0000 0.0000 0.3516 0.0643 0.0103 0.0000 0.0000 0.3956 0.0643 0.0116 0.0000 0.0000 0.4396 0.0643 0.0129 0.0000 0.0000 0.4835 0.0643 0.0142 0.0000 0.0000 0.5275 0.0643 0.0155 0.0000 0.0000 0.5714 0.0643 0.0168 0.0000 0.0000 0.6154 0.0643 0.0181 0.0000 0.0000 0.6593 0.0643 0.0194 0.0000 0.0000 0.7033 0.0643 0.0207 0.0000 0.0000 0.7473 0.0643 0.0220 0.0000 0.0000 Drainage Report Lindsay Project 1 06-Feb-2026 13-18 0.7912 0.0643 0.0233 0.0000 0.0000 0.8352 0.0643 0.0245 0.0000 0.0000 0.8791 0.0643 0.0258 0.0000 0.0000 0.9231 0.0643 0.0271 0.0000 0.0000 0.9670 0.0643 0.0284 0.0000 0.0000 1.0110 0.0643 0.0297 0.0000 0.0000 1.0549 0.0643 0.0310 0.0000 0.0000 1.0989 0.0643 0.0323 0.0000 0.0000 1.1429 0.0643 0.0336 0.0000 0.0000 1.1868 0.0643 0.0349 0.0000 0.0000 1.2308 0.0643 0.0362 0.0000 0.0000 1.2747 0.0643 0.0375 0.0000 0.0000 1.3187 0.0643 0.0388 0.0000 0.0000 1.3626 0.0643 0.0401 0.0000 0.0000 1.4066 0.0643 0.0413 0.0000 0.0000 1.4505 0.0643 0.0426 0.0000 0.0000 1.4945 0.0643 0.0439 0.0000 0.0000 1.5385 0.0643 0.0451 0.0000 0.0000 1.5824 0.0643 0.0462 0.0000 0.0000 1.6264 0.0643 0.0473 0.0000 0.0000 1.6703 0.0643 0.0485 0.0000 0.0000 1.7143 0.0643 0.0496 0.0000 0.0000 1.7582 0.0643 0.0507 0.0000 0.0000 1.8022 0.0643 0.0518 0.0000 0.0000 1.8462 0.0643 0.0530 0.0000 0.0000 1.8901 0.0643 0.0541 0.0000 0.0000 1.9341 0.0643 0.0552 0.0000 0.0000 1.9780 0.0643 0.0564 0.0000 0.0000 2.0220 0.0643 0.0575 0.0000 0.0000 2.0659 0.0643 0.0587 0.0000 0.0000 2.1099 0.0643 0.0599 0.0000 0.0000 2.1538 0.0643 0.0611 0.0000 0.0000 2.1978 0.0643 0.0622 0.0000 0.0000 2.2418 0.0643 0.0634 0.0000 0.0000 2.2857 0.0643 0.0646 0.0000 0.0000 2.3297 0.0643 0.0657 0.0000 0.0000 2.3736 0.0643 0.0669 0.0000 0.0000 2.4176 0.0643 0.0681 0.0000 0.0000 2.4615 0.0643 0.0693 0.0000 0.0000 2.5000 0.0643 0.0703 0.0000 0.0000 Surface retention 1 Hydraulic Table Stage(£eet) Area(ac.) Volume(ac-ft.) Discharge(cfs) To Amended(cfs) Wetted Surface 2.5000 0.0643 0.0703 0.0000 0.7778 0.0000 2.5440 0.0649 0.0731 0.0000 0.7778 0.0000 2.5879 0.0656 0.0760 0.0000 0.8234 0.0000 2.6319 0.0663 0.0789 0.0000 0.8462 0.0000 2.6758 0.0670 0.0818 0.0000 0.8689 0.0000 2.7198 0.0676 0.0848 0.0000 0.8917 0.0000 2.7637 0.0683 0.0878 0.0035 0.9145 0.0000 2.8077 0.0690 0.0908 0.0060 0.9373 0.0000 2.8516 0.0697 0.0938 0.0073 0.9601 0.0000 2.8956 0.0704 0.0969 0.0080 0.9829 0.0000 2.9396 0.0711 0.1000 0.0146 1.0057 0.0000 2.9835 0.0718 0.1032 0.0159 1.0285 0.0000 3.0275 0.0725 0.1063 0.0216 1.0513 0.0000 3.0714 0.0732 0.1095 0.0286 1.0741 0.0000 3.1154 0.0739 0.1128 0.0314 1.0969 0.0000 Drainage Report Lindsay Project 1 06-Feb-2026 13-19 3.1593 0.0746 0.1160 0.0367 1.1197 0.0000 3.2033 0.0753 0.1193 0.0378 1.1425 0.0000 3.2473 0.0761 0.1227 0.0383 1.1652 0.0000 3.2912 0.0768 0.1260 0.0461 1.1880 0.0000 3.3352 0.0775 0.1294 0.0500 1.2108 0.0000 3.3791 0.0782 0.1328 0.0577 1.2336 0.0000 3.4231 0.0790 0.1363 0.0616 1.2564 0.0000 3.4670 0.0797 0.1398 0.0684 1.2792 0.0000 3.5110 0.0804 0.1433 0.0718 1.3020 0.0000 3.5549 0.0812 0.1469 0.0778 1.3248 0.0000 3.5989 0.0819 0.1504 0.0808 1.3476 0.0000 3.6429 0.0827 0.1541 0.0861 1.3704 0.0000 3.6868 0.0834 0.1577 0.0888 1.3932 0.0000 3.7308 0.0842 0.1614 0.0937 1.4160 0.0000 3.7747 0.0849 0.1651 0.0962 1.4387 0.0000 3.8187 0.0857 0.1689 0.1007 1.4615 0.0000 3.8626 0.0865 0.1726 0.1030 1.4843 0.0000 3.9066 0.0872 0.1765 0.1072 1.5071 0.0000 3.9505 0.0880 0.1803 0.1093 1.5299 0.0000 3.9945 0.0888 0.1842 0.1133 1.5527 0.0000 4.0000 0.0889 0.1847 0.1153 1.5556 0.0000 Name Surface retention 1 Element Flows To: Outlet 1 Outlet 2 Vault 1 Bioretention 1 Name : frntg Bypass: No GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.4 SIDEWALKS FLAT 0.06 Impervious Total 0.46 Basin Total 0.46 Element Flows To: Surface Interflow Groundwater Surface retention 1 Surface retention 1 Name Time Series 1 Time Series number 849 is connected to: Element Flows To: Outlet 1 Outlet 2 Vault 1 Drainage Report Lindsay Project 1 06-Feb-2026 13-20 Name : Bioretention 2 Bottom Length: 720.00 ft. Bottom Width: 5.00 ft. Material thickness of first layer: 1.5 Material type for first layer: SMMWW 12 in/hr Material thickness of second layer: 0.5 Material type for second layer: Sand Material thickness of third layer: 2 Material type for third layer: GRAVEL Underdrain used Underdrain Diameter (feet) : 0.5 Orifice Diameter (in.) : 0.75 Offset (in.) : 0 Flow Through Underdrain (ac-ft.) : 634.748 Total Outflow (ac-ft.) : 651.451 Percent Through Underdrain: 97.44 Discharge Structure Riser Height: 1 ft. Riser Diameter: 12 in. Element Flows To: Outlet 1 Outlet 2 Vault 1 Bioretention 2 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.0826 0.0000 0.0000 0.0000 0.0604 0.0826 0.0023 0.0000 0.0000 0.1209 0.0826 0.0046 0.0000 0.0000 0.1813 0.0826 0.0069 0.0000 0.0000 0.2418 0.0826 0.0091 0.0000 0.0000 0.3022 0.0826 0.0114 0.0000 0.0000 0.3626 0.0826 0.0137 0.0008 0.0000 0.4231 0.0826 0.0160 0.0013 0.0000 0.4835 0.0826 0.0183 0.0027 0.0000 0.5440 0.0826 0.0206 0.0035 0.0000 0.6044 0.0826 0.0228 0.0042 0.0000 0. 6648 0.0826 0.0251 0.0046 0.0000 0.7253 0.0826 0.0274 0.0052 0.0000 0.7857 0.0826 0.0297 0.0054 0.0000 0.8462 0.0826 0.0320 0.0059 0.0000 0.9066 0.0826 0.0343 0.0061 0.0000 0.9670 0.0826 0.0365 0.0065 0.0000 1.0275 0.0826 0.0388 0.0066 0.0000 1.0879 0.0826 0.0411 0.0070 0.0000 1.1484 0.0826 0.0434 0.0072 0.0000 1.2088 0.0826 0.0457 0.0075 0.0000 1.2692 0.0826 0.0480 0.0077 0.0000 1.3297 0.0826 0.0503 0.0080 0.0000 1.3901 0.0826 0.0525 0.0081 0.0000 1.4505 0.0826 0.0548 0.0084 0.0000 1.5110 0.0826 0.0568 0.0085 0.0000 1.5714 0.0826 0.0588 0.0088 0.0000 1.6319 0.0826 0.0608 0.0089 0.0000 1.6923 0.0826 0.0628 0.0092 0.0000 1.7527 0.0826 0.0648 0.0093 0.0000 Drainage Report Lindsay Project 1 06-Feb-2026 13-21 1.8132 0.0826 0.0668 0.0096 0.0000 1.8736 0.0826 0.0688 0.0097 0.0000 1.9341 0.0826 0.0708 0.0100 0.0000 1.9945 0.0826 0.0728 0.0101 0.0000 2.0549 0.0826 0.0749 0.0103 0.0000 2.1154 0.0826 0.0769 0.0104 0.0000 2.1758 0.0826 0.0790 0.0106 0.0000 2.2363 0.0826 0.0811 0.0108 0.0000 2.2967 0.0826 0.0832 0.0110 0.0000 2.3571 0.0826 0.0852 0.0111 0.0000 2.4176 0.0826 0.0873 0.0113 0.0000 2.4780 0.0826 0.0894 0.0114 0.0000 2.5385 0.0826 0.0915 0.0115 0.0000 2.5989 0.0826 0.0935 0.0115 0.0000 2.6593 0.0826 0.0956 0.0118 0.0000 2.7198 0.0826 0.0977 0.0122 0.0000 2.7802 0.0826 0.0998 0.0127 0.0000 2.8407 0.0826 0.1018 0.0132 0.0000 2.9011 0.0826 0.1039 0.0137 0.0000 2.9615 0.0826 0.1060 0.0142 0.0000 3.0220 0.0826 0.1080 0.0147 0.0000 3.0824 0.0826 0.1101 0.0152 0.0000 3.1429 0.0826 0.1122 0.0156 0.0000 3.2033 0.0826 0.1143 0.0161 0.0000 3.2637 0.0826 0.1163 0.0165 0.0000 3.3242 0.0826 0.1184 0.0169 0.0000 3.3846 0.0826 0.1205 0.0173 0.0000 3.4451 0.0826 0.1226 0.0178 0.0000 3.5055 0.0826 0.1246 0.0181 0.0000 3.5659 0.0826 0.1267 0.0185 0.0000 3.6264 0.0826 0.1288 0.0189 0.0000 3.6868 0.0826 0.1308 0.0193 0.0000 3.7473 0.0826 0.1329 0.0197 0.0000 3.8077 0.0826 0.1350 0.0200 0.0000 3.8681 0.0826 0.1371 0.0204 0.0000 3.9286 0.0826 0.1391 0.0207 0.0000 3.9890 0.0826 0.1412 0.0211 0.0000 4.0000 0.0826 0.1416 0.0305 0.0000 Surface retention 2 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) To Amended(cfs) Wetted Surface 4.0000 0.0826 0.1416 0.0000 1.0000 0.0000 4.0604 0.0887 0.1468 0.0000 1.0000 0.0000 4.1209 0.0947 0.1523 0.0000 1.0806 0.0000 4.1813 0.1008 0.1582 0.0000 1.1209 0.0000 4.2418 0.1068 0.1645 0.0000 1.1612 0.0000 4.3022 0.1129 0.1711 0.0000 1.2015 0.0000 4.3626 0.1190 0.1781 0.0000 1.2418 0.0000 4.4231 0.1250 0.1855 0.0000 1.2821 0.0000 4.4835 0.1311 0.1933 0.0000 1.3223 0.0000 4.5440 0.1372 0.2014 0.0000 1.3626 0.0000 4.6044 0.1433 0.2098 0.0000 1.4029 0.0000 4.6648 0.1494 0.2187 0.0000 1.4432 0.0000 4.7253 0.1555 0.2279 0.0000 1.4835 0.0000 4.7857 0.1616 0.2375 0.0000 1.5238 0.0000 4.8462 0.1677 0.2474 0.0000 1.5641 0.0000 4.9066 0.1739 0.2578 0.0000 1.6044 0.0000 4.9670 0.1800 0.2684 0.0000 1.6447 0.0000 Drainage Report Lindsay Project 1 06-Feb-2026 13-22 5.0275 0.1861 0.2795 0.0483 1.6850 0.0000 5.0879 0.1923 0.2909 0.2754 1.7253 0.0000 5.1484 0.1984 0.3028 0.5952 1.7656 0.0000 5.2088 0.2046 0.3149 0.9624 1.8059 0.0000 5.2692 0.2107 0.3275 1.3333 1.8462 0.0000 5.3297 0.2169 0.3404 1.6654 1.8864 0.0000 5.3901 0.2231 0.3537 1.9255 1.9267 0.0000 5.4505 0.2292 0.3674 2.1028 1.9670 0.0000 5.5000 0.2343 0.3788 2.2515 2.0000 0.0000 Name Surface retention 2 Element Flows To: Outlet 1 Outlet 2 Vault 1 Bioretention 2 Name : Time Series 2 Time Series number 830 is connected to: Element Flows To: Outlet 1 Outlet 2 Surface retention 2 Name Basin 3 Bypass: Yes GroundWater: No Pervious Land Use acre C, Pasture, Flat .75 Pervious Total 0.75 Impervious Land Use acre Impervious Total 0 Basin Total 0.75 Element Flows To: Surface Interflow Groundwater ANALYSIS RESULTS Stream Protection Duration Predeveloped Landuse Totals for POC #1 Total Pervious Area:12.81 Total Impervious Area:O Mitigated Landuse Totals for POC #1 Total Pervious Area:0.75 Total Impervious Area:3.69 Flow Frequency Return Periods for Predeveloped. POC #1 Drainage Report Lindsay Project 1 06-Feb-2026 13-23 Return Period Flow(cfs) 2 year 0.319581 5 year 0.474704 10 year 0.565067 25 year 0.664995 50 year 0.730004 100 year 0.787893 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.203467 5 year 0.358589 10 year 0.516462 25 year 0.805136 50 year 1.106533 100 year 1.504751 Stream Protection Duration POC #1 The Facility PASSED The Facility PASSED. Flow(cfs) Predev Mit Percentage Pass/Fail 0.1598 48174 46490 96 Pass 0.1656 43974 40242 91 Pass 0.1713 40137 34572 86 Pass 0.1771 36730 29777 81 Pass 0.1828 34247 26529 77 Pass 0.1886 31566 23281 73 Pass 0.1943 29078 20220 69 Pass 0.2001 26793 17655 65 Pass 0.2059 25081 16020 63 Pass 0.2116 23160 14192 61 Pass 0.2174 21348 12794 59 Pass 0.2231 19774 11511 58 Pass 0.2289 18552 10493 56 Pass 0.2347 17236 9606 55 Pass 0.2404 16047 8902 55 Pass 0.2462 14858 8417 56 Pass 0.2519 13977 8147 58 Pass 0.2577 13008 7834 60 Pass 0.2635 12095 7476 61 Pass 0.2692 11236 7074 62 Pass 0.2750 10603 6749 63 Pass 0.2807 9909 6369 64 Pass 0.2865 9292 6011 64 Pass 0.2923 8698 5698 65 Pass 0.2980 8114 5354 65 Pass 0.3038 7663 5101 66 Pass 0.3095 7212 4804 66 Pass 0.3153 6782 4593 67 Pass 0.3211 6402 4357 68 Pass 0.3268 6116 4178 68 Pass 0.3326 5780 4001 69 Pass 0.3383 5456 3829 70 Pass 0.3441 5154 3636 70 Pass 0.3499 4922 3469 70 Pass Drainage Report Lindsay Project 1 06-Feb-2026 13-24 0.3556 4674 3312 70 Pass 0.3614 4427 3131 70 Pass 0.3671 4171 3005 72 Pass 0.3729 3995 2888 72 Pass 0.3787 3798 2732 71 Pass 0.3844 3591 2591 72 Pass 0.3902 3398 2479 72 Pass 0.3959 3252 2348 72 Pass 0.4017 3106 2230 71 Pass 0.4075 2970 2123 71 Pass 0.4132 2834 2014 71 Pass 0.4190 2722 1957 71 Pass 0.4247 2612 1884 72 Pass 0.4305 2500 1810 72 Pass 0.4363 2377 1728 72 Pass 0.4420 2292 1638 71 Pass 0.4478 2222 1584 71 Pass 0.4535 2150 1526 70 Pass 0.4593 2076 1460 70 Pass 0.4651 1985 1409 70 Pass 0.4708 1898 1366 71 Pass 0.4766 1800 1315 73 Pass 0.4823 1700 1272 74 Pass 0.4881 1610 1211 75 Pass 0.4939 1557 1169 75 Pass 0.4996 1481 1102 74 Pass 0.5054 1400 1069 76 Pass 0.5111 1334 1024 76 Pass 0.5169 1282 983 76 Pass 0.5227 1238 937 75 Pass 0.5284 1176 903 76 Pass 0.5342 1107 863 77 Pass 0.5399 1065 807 75 Pass 0.5457 1015 770 75 Pass 0.5515 964 739 76 Pass 0.5572 914 696 76 Pass 0.5630 872 672 77 Pass 0.5687 835 649 77 Pass 0.5745 799 632 79 Pass 0.5803 767 602 78 Pass 0.5860 724 571 78 Pass 0.5918 694 548 78 Pass 0.5975 659 525 79 Pass 0.6033 627 498 79 Pass 0.6090 585 462 78 Pass 0.6148 541 428 79 Pass 0.6206 488 386 79 Pass 0.6263 447 357 79 Pass 0.6321 420 334 79 Pass 0.6378 402 314 78 Pass 0.6436 378 287 75 Pass 0.6494 349 260 74 Pass 0.6551 325 233 71 Pass 0.6609 312 204 65 Pass 0.6666 292 178 60 Pass 0.6724 272 155 56 Pass 0.6782 255 141 55 Pass 0.6839 240 135 56 Pass Drainage Report Lindsay Project 1 06-Feb-2026 13-25 0.6897 224 130 58 Pass 0.6954 210 128 60 Pass 0.7012 195 126 64 Pass 0.7070 176 120 68 Pass 0.7127 159 116 72 Pass 0.7185 140 115 82 Pass 0.7242 127 112 88 Pass 0.7300 115 110 95 Pass 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. LID Report LID Technique Used for Total Volume Volume Infiltration Cumulative Percent Water Quality Percent Comment Treatment? Needs Through Volume Volume Volume Water Quality Treatment Facility (ac-ft.) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit Vault 1 POC N 2992.82 N 0.00 retention 1 N 1458.77 N 0.00 retention 2 N 592.82 N 0.00 Total Volume Infiltrated 5044.41 0.00 0.00 0.00 0.00 0% No Treat. Credit Compliance with LID Standard 8 Duration Analysis Result = Failed 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 © by : Clear Creek Solutions, Inc. 2005-2025; All Rights Reserved. 13.2 Southwest Basin WWHM2012 PROJECT REPORT Project Name: SW Basin 3cells Vlt WSDOT 37x37 Site Name: Lindsay Annexation Site Address: 172nd St NE City : Arlington Report Date: 2/6/2026 MGS Regoin Puget East Data Start 1901/10/1 Data End : 2058/09/30 DOT Data Number: 04 Version Date: 2025/05/13 Version : 4.3.2 Drainage Report Lindsay Project 1 06-Feb-2026 13-26 Low Flow Threshold for POC 1 : 50 Percent of the 2 Year High Flow Threshold for POC 1: 50 year PREDEVELOPED LAND USE Name : Basin 1 Bypass: No Groundwater: No Pervious Land Use acre C, Forest, Flat 10.16 Pervious Total 10.16 Impervious Land Use acre Impervious Total 0 Basin Total 10.16 Element Flows To: Surface Interflow Groundwater MITIGATED LAND USE Name : Basin A Bypass: No Groundwater: No Pervious Land Use acre C, Pasture, Flat 1.57 Pervious Total 1.57 Impervious Land Use acre ROADS FLAT 0.15 ROOF TOPS FLAT 0.88 DRIVEWAYS FLAT 0.14 Impervious Total 1.17 Basin Total 2.74 Element Flows To: Surface Interflow Groundwater Surface retention A Surface retention A Name Bioretention A Bottom Length: 204.00 ft. Bottom Width: 20.00 ft. Material thickness of first layer: 1.5 Material type for first layer: SMMWW 12 in/hr Material thickness of second layer: 0.5 Material type for second layer: Sand Material thickness of third layer: 2 Material type for third layer: GRAVEL Drainage Report Lindsay Project 1 06-Feb-2026 13-27 Underdrain used Underdrain Diameter (feet) : 0.5 Orifice Diameter (in. ) : 0.-75 Offset (in. ) : 0 Flow Through Underdrain (ac-ft. ) : 675.404 Total Outflow (ac-ft. ) : 712.726 Percent Through Underdrain: 94.76 Discharge Structure Riser Height: 1 ft. Riser Diameter: 12 in. Notch Type: Rectangular Notch Width: 0.125 ft. Notch Height: 0.250 ft. Element Flows To: Outlet 1 Outlet 2 Surface retention BB Bioretention A Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.0937 0.0000 0.0000 0.0000 0.0604 0.0937 0.0026 0.0000 0.0000 0.1209 0.0937 0.0052 0.0000 0.0000 0.1813 0.0937 0.0078 0.0000 0.0000 0.2418 0.0937 0.0104 0.0000 0.0000 0.3022 0.0937 0.0129 0.0000 0.0000 0.3626 0.0937 0.0155 0.0008 0.0000 0.4231 0.0937 0.0181 0.0013 0.0000 0.4835 0.0937 0.0207 0.0027 0.0000 0.5440 0.0937 0.0233 0.0035 0.0000 0.6044 0.0937 0.0259 0.0042 0.0000 0.6648 0.0937 0.0285 0.0046 0.0000 0.7253 0.0937 0.0311 0.0052 0.0000 0.7857 0.0937 0.0337 0.0054 0.0000 0.8462 0.0937 0.0362 0.0059 0.0000 0.9066 0.0937 0.0388 0.0061 0.0000 0.9670 0.0937 0.0414 0.0065 0.0000 1.0275 0.0937 0.0440 0.0066 0.0000 1.0879 0.0937 0.0466 0.0070 0.0000 1.1484 0.0937 0.0492 0.0072 0.0000 1.2088 0.0937 0.0518 0.0075 0.0000 1.2692 0.0937 0.0544 0.0077 0.0000 1.3297 0.0937 0.0570 0.0080 0.0000 1.3901 0.0937 0.0595 0.0081 0.0000 1.4505 0.0937 0.0621 0.0084 0.0000 1.5110 0.0937 0.0644 0.0085 0.0000 1.5714 0.0937 0.0667 0.0088 0.0000 1.6319 0.0937 0.0689 0.0089 0.0000 1.6923 0.0937 0.0712 0.0092 0.0000 1.7527 0.0937 0.0735 0.0093 0.0000 1.8132 0.0937 0.0757 0.0096 0.0000 1.8736 0.0937 0.0780 0.0097 0.0000 1.9341 0.0937 0.0802 0.0100 0.0000 1.9945 0.0937 0.0825 0.0101 0.0000 2.0549 0.0937 0.0849 0.0103 0.0000 2.1154 0.0937 0.0872 0.0104 0.0000 2.1758 0.0937 0.0896 0.0106 0.0000 Drainage Report Lindsay Project 1 06-Feb-2026 13-28 2.2363 0.0937 0.0919 0.0108 0.0000 2.2967 0.0937 0.0943 0.0110 0.0000 2.3571 0.0937 0.0966 0.0111 0.0000 2.4176 0.0937 0.0990 0.0113 0.0000 2.4780 0.0937 0.1013 0.0114 0.0000 2.5385 0.0937 0.1037 0.0115 0.0000 2.5989 0.0937 0.1060 0.0115 0.0000 2.6593 0.0937 0.1084 0.0118 0.0000 2.7198 0.0937 0.1107 0.0122 0.0000 2.7802 0.0937 0.1131 0.0127 0.0000 2.8407 0.0937 0.1154 0.0132 0.0000 2.9011 0.0937 0.1178 0.0137 0.0000 2.9615 0.0937 0.1201 0.0142 0.0000 3.0220 0.0937 0.1224 0.0147 0.0000 3.0824 0.0937 0.1248 0.0152 0.0000 3.1429 0.0937 0.1271 0.0156 0.0000 3.2033 0.0937 0.1295 0.0161 0.0000 3.2637 0.0937 0.1318 0.0165 0.0000 3.3242 0.0937 0.1342 0.0169 0.0000 3.3846 0.0937 0.1365 0.0173 0.0000 3.4451 0.0937 0.1389 0.0178 0.0000 3.5055 0.0937 0.1412 0.0181 0.0000 3.5659 0.0937 0.1436 0.0185 0.0000 3.6264 0.0937 0.1459 0.0189 0.0000 3.6868 0.0937 0.1483 0.0193 0.0000 3.7473 0.0937 0.1506 0.0197 0.0000 3.8077 0.0937 0.1530 0.0200 0.0000 3.8681 0.0937 0.1553 0.0204 0.0000 3.9286 0.0937 0.1577 0.0207 0.0000 3.9890 0.0937 0.1600 0.0211 0.0000 4.0000 0.0937 0.1605 0.0305 0.0000 Surface retention A Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) To Amended(cfs) Wetted Surface 4.0000 0.0937 0.1605 0.0000 1.1333 0.0000 4.0604 0.0955 0.1662 0.0000 1.1333 0.0000 4.1209 0.0974 0.1720 0.0000 1.2247 0.0000 4.1813 0.0993 0.1780 0.0000 1.2703 0.0000 4.2418 0.1012 0.1840 0.0000 1.3160 0.0000 4.3022 0.1031 0.1902 0.0000 1.3617 0.0000 4.3626 0.1050 0.1965 0.0000 1.4073 0.0000 4.4231 0.1069 0.2029 0.0000 1.4530 0.0000 4.4835 0.1088 0.2094 0.0000 1.4987 0.0000 4.5440 0.1107 0.2160 0.0000 1.5443 0.0000 4.6044 0.1126 0.2228 0.0000 1.5900 0.0000 4.6648 0.1145 0.2296 0.0000 1.6357 0.0000 4.7253 0.1165 0.2366 0.0000 1.6813 0.0000 4.7857 0.1184 0.2437 0.0028 1.7270 0.0000 4.8462 0.1204 0.2509 0.0124 1.7727 0.0000 4.9066 0.1223 0.2583 0.0258 1.8183 0.0000 4.9670 0.1243 0.2657 0.0421 1.8640 0.0000 5.0275 0.1262 0.2733 0.1003 1.9096 0.0000 5.0879 0.1282 0.2810 0.3274 1.9553 0.0000 5.1484 0.1302 0.2888 0.6472 2.0010 0.0000 5.2088 0.1322 0.2967 1.0144 2.0466 0.0000 5.2692 0.1342 0.3048 1.3853 2.0923 0.0000 5.3297 0.1362 0.3129 1.7174 2.1380 0.0000 5.3901 0.1382 0.3212 1.9776 2.1836 0.0000 Drainage Report Lindsay Project 1 06-Feb-2026 13-29 5.4505 0.1402 0.3296 2.1548 2.2293 0.0000 5.5000 0.1418 0.3366 2.3035 2.2667 0.0000 Name Surface retention A Element Flows To: Outlet 1 Outlet 2 Surface retention BB Bioretention A Name Basin B Bypass: No Groundwater: No Pervious Land Use acre C, Pasture, Flat 1.01 Pervious Total 1.01 Impervious Land Use acre ROADS FLAT 0.39 ROOF TOPS FLAT 0.52 DRIVEWAYS FLAT 0.3 Impervious Total 1.21 Basin Total 2.22 Element Flows To: Surface Interflow Groundwater Surface retention BB Surface retention BB Name Basin c Bypass: No Groundwater: No Pervious Land Use acre C. Pasture, Flat 1.27 Pervious Total 1.27 Impervious Land Use acre ROADS FLAT 0.29 ROOF TOPS FLAT 0.64 DRIVEWAYS FLAT 0.15 Impervious Total 1.08 Basin Total 2.35 Element Flows To: Surface Interflow Groundwater Surface retention 3 Surface retention 3 Name Bioretention 3 Bottom Length: 169.50 ft. Bottom Width: 30.00 ft. Material thickness of first layer: 1.5 Material type for first layer: SMMWW 12 in/hr Material thickness of second layer: 0.5 Drainage Report Lindsay Project 1 06-Feb-2026 13-30 Material type for second layer: Sand Material thickness of third layer: 2 Material type for third layer: GRAVEL Underdrain used Underdrain Diameter (feet) : 0.5 Orifice Diameter (in. ) : 2.5 Offset (in. ) : 0 Flow Through Underdrain (ac-ft. ) : 1995.261 Total Outflow (ac-ft. ) : 2003.595 Percent Through Underdrain: 99.58 Discharge Structure Riser Height: 1 ft. Riser Diameter: 12 in. Notch Type: Rectangular Notch Width: 0.125 ft. Notch Height: 0.250 ft. Element Flows To: Outlet 1 Outlet 2 Vault 1 Bioretention 3 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.1167 0.0000 0.0000 0.0000 0.0604 0.1167 0.0032 0.0000 0.0000 0.1209 0.1167 0.0065 0.0000 0.0000 0.1813 0.1167 0.0097 0.0000 0.0000 0.2418 0.1167 0.0129 0.0000 0.0000 0.3022 0.1167 0.0161 0.0000 0.0000 0.3626 0.1167 0.0194 0.0115 0.0000 0.4231 0.1167 0.0226 0.0167 0.0000 0.4835 0.1167 0.0258 0.0203 0.0000 0.5440 0.1167 0.0290 0.0325 0.0000 0.6044 0.1167 0.0323 0.0397 0.0000 0.6648 0.1167 0.0355 0.0433 0.0000 0.7253 0.1167 0.0387 0.0494 0.0000 0.7857 0.1167 0.0419 0.0525 0.0000 0.8462 0.1167 0.0452 0.0579 0.0000 0.9066 0.1167 0.0484 0.0605 0.0000 0.9670 0.1167 0.0516 0.0652 0.0000 1.0275 0.1167 0.0548 0.0675 0.0000 1.0879 0.1167 0.0581 0.0718 0.0000 1.1484 0.1167 0.0613 0.0739 0.0000 1.2088 0.1167 0.0645 0.0777 0.0000 1.2692 0.1167 0.0678 0.0797 0.0000 1.3297 0.1167 0.0710 0.0833 0.0000 1.3901 0.1167 0.0742 0.0851 0.0000 1.4505 0.1167 0.0774 0.0884 0.0000 1.5110 0.1167 0.0803 0.0901 0.0000 1.5714 0.1167 0.0831 0.0933 0.0000 1.6319 0.1167 0.0859 0.0949 0.0000 1.6923 0.1167 0.0887 0.0979 0.0000 1.7527 0.1167 0.0915 0.0994 0.0000 1.8132 0.1167 0.0944 0.1023 0.0000 1.8736 0.1167 0.0972 0.1038 0.0000 1.9341 0.1167 0.1000 0.1065 0.0000 1.9945 0.1167 0.1028 0.1079 0.0000 2.0549 0.1167 0.1058 0.1106 0.0000 Drainage Report Lindsay Project 1 06-Feb-2026 13-31 2.1154 0.1167 0.1087 0.1119 0.0000 2.1758 0.1167 0.1116 0.1145 0.0000 2.2363 0.1167 0.1145 0.1158 0.0000 2.2967 0.1167 0.1175 0.1183 0.0000 2.3571 0.1167 0.1204 0.1195 0.0000 2.4176 0.1167 0.1233 0.1219 0.0000 2.4780 0.1167 0.1263 0.1231 0.0000 2.5385 0.1167 0.1292 0.1255 0.0000 2.5989 0.1167 0.1321 0.1267 0.0000 2.6593 0.1167 0.1350 0.1303 0.0000 2.7198 0.1167 0.1380 0.1353 0.0000 2.7802 0.1167 0.1409 0.1409 0.0000 2.8407 0.1167 0.1438 0.1466 0.0000 2.9011 0.1167 0.1468 0.1523 0.0000 2.9615 0.1167 0.1497 0.1578 0.0000 3.0220 0.1167 0.1526 0.1632 0.0000 3.0824 0.1167 0.1555 0.1685 0.0000 3.1429 0.1167 0.1585 0.1736 0.0000 3.2033 0.1167 0.1614 0.1786 0.0000 3.2637 0.1167 0.1643 0.1834 0.0000 3.3242 0.1167 0.1673 0.1881 0.0000 3.3846 0.1167 0.1702 0.1928 0.0000 3.4451 0.1167 0.1731 0.1972 0.0000 3.5055 0.1167 0.1760 0.2016 0.0000 3.5659 0.1167 0.1790 0.2059 0.0000 3.6264 0.1167 0.1819 0.2102 0.0000 3.6868 0.1167 0.1848 0.2143 0.0000 3.7473 0.1167 0.1877 0.2184 0.0000 3.8077 0.1167 0.1907 0.2224 0.0000 3.8681 0.1167 0.1936 0.2263 0.0000 3.9286 0.1167 0.1965 0.2302 0.0000 3.9890 0.1167 0.1995 0.2341 0.0000 4.0000 0.1167 0.2000 0.3392 0.0000 Surface retention 3 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) To Amended(cfs) Wetted Surface 4.0000 0.1167 0.2000 0.0000 1.4125 0.0000 4.0604 0.1184 0.2071 0.0000 1.4125 0.0000 4.1209 0.1201 0.2143 0.0000 1.5263 0.0000 4.1813 0.1217 0.2216 0.0000 1.5832 0.0000 4.2418 0.1234 0.2290 0.0000 1.6402 0.0000 4.3022 0.1251 0.2365 0.0000 1.6971 0.0000 4.3626 0.1268 0.2441 0.0000 1.7540 0.0000 4.4231 0.1285 0.2519 0.0000 1.8109 0.0000 4.4835 0.1302 0.2597 0.0000 1.8678 0.0000 4.5440 0.1319 0.2676 0.0000 1.9247 0.0000 4.6044 0.1336 0.2756 0.0000 1.9816 0.0000 4.6648 0.1354 0.2838 0.0000 2.0386 0.0000 4.7253 0.1371 0.2920 0.0000 2.0955 0.0000 4.7857 0.1388 0.3003 0.0028 2.1524 0.0000 4.8462 0.1406 0.3088 0.0124 2.2093 0.0000 4.9066 0.1423 0.3173 0.0258 2.2662 0.0000 4.9670 0.1441 0.3260 0.0421 2.3231 0.0000 5.0275 0.1458 0.3347 0.1003 2.3800 0.0000 5.0879 0.1476 0.3436 0.3274 2.4370 0.0000 5.1484 0.1494 0.3526 0.6472 2.4939 0.0000 5.2088 0.1512 0.3617 1.0144 2.5508 0.0000 5.2692 0.1529 0.3709 1.3853 2.6077 0.0000 Drainage Report Lindsay Project 1 06-Feb-2026 13-32 5.3297 0.1547 0.3802 1.7174 2.6646 0.0000 5.3901 0.1565 0.3896 1.9776 2.7215 0.0000 5.4505 0.1583 0.3991 2.1548 2.7784 0.0000 5.5000 0.1598 0.4069 2.3035 2.8250 0.0000 Name Surface retention 3 Element Flows To: Outlet 1 Outlet 2 Vault 1 Bioretention 3 Name : Bioretention BB Bottom Length: 168.70 ft. Bottom Width: 15.00 ft. Material thickness of first layer: 1.5 Material type for first layer: SMMWW 12 in/hr Material thickness of second layer: 0.5 Material type for second layer: Sand Material thickness of third layer: 2.5 Material type for third layer: GRAVEL Underdrain used Underdrain Diameter (feet) : 0.5 Orifice Diameter (in.) : 1.5 Offset (in.) : 0 Flow Through Underdrain (ac-ft.) : 1344.457 Total Outflow (ac-ft.) : 1365.677 Percent Through Underdrain: 98.45 Discharge Structure Riser Height: 1 ft. Riser Diameter: 12 in. Notch Type: Rectangular Notch Width: 0.125 ft. Notch Height: 0.250 ft. Element Flows To: Outlet 1 Outlet 2 Surface retention 3 Bioretention BB Hydraulic Table Stage(£eet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.0581 0.0000 0.0000 0.0000 0.0659 0.0581 0.0018 0.0000 0.0000 0.1319 0.0581 0.0035 0.0000 0.0000 0.1978 0.0581 0.0053 0.0000 0.0000 0.2637 0.0581 0.0070 0.0000 0.0000 0.3297 0.0581 0.0088 0.0032 0.0000 0.3956 0.0581 0.0105 0.0057 0.0000 0.4615 0.0581 0.0123 0.0067 0.0000 0.5275 0.0581 0.0140 0.0121 0.0000 0.5934 0.0581 0.0158 0.0150 0.0000 0.6593 0.0581 0.0175 0.0194 0.0000 0.7253 0.0581 0.0193 0.0217 0.0000 0.7912 0.0581 0.0210 0.0229 0.0000 0.8571 0.0581 0.0228 0.0247 0.0000 0.9231 0.0581 0.0245 0.0256 0.0000 0.9890 0.0581 0.0263 0.0272 0.0000 Drainage Report Lindsay Project 1 06-Feb-2026 13-33 1.0549 0.0581 0.0280 0.0280 0.0000 1.1209 0.0581 0.0298 0.0294 0.0000 1.1868 0.0581 0.0315 0.0301 0.0000 1.2527 0.0581 0.0333 0.0315 0.0000 1.3187 0.0581 0.0350 0.0322 0.0000 1.3846 0.0581 0.0368 0.0334 0.0000 1.4505 0.0581 0.0385 0.0340 0.0000 1.5165 0.0581 0.0401 0.0352 0.0000 1.5824 0.0581 0.0416 0.0358 0.0000 1.6484 0.0581 0.0431 0.0370 0.0000 1.7143 0.0581 0.0447 0.0375 0.0000 1.7802 0.0581 0.0462 0.0386 0.0000 1.8462 0.0581 0.0477 0.0392 0.0000 1.9121 0.0581 0.0493 0.0402 0.0000 1.9780 0.0581 0.0508 0.0407 0.0000 2.0440 0.0581 0.0524 0.0417 0.0000 2.1099 0.0581 0.0540 0.0422 0.0000 2.1758 0.0581 0.0556 0.0432 0.0000 2.2418 0.0581 0.0571 0.0437 0.0000 2.3077 0.0581 0.0587 0.0446 0.0000 2.3736 0.0581 0.0603 0.0451 0.0000 2.4396 0.0581 0.0619 0.0460 0.0000 2.5055 0.0581 0.0635 0.0464 0.0000 2.5714 0.0581 0.0651 0.0473 0.0000 2.6374 0.0581 0.0667 0.0477 0.0000 2.7033 0.0581 0.0683 0.0488 0.0000 2.7692 0.0581 0.0699 0.0505 0.0000 2.8352 0.0581 0.0715 0.0526 0.0000 2.9011 0.0581 0.0730 0.0547 0.0000 2.9670 0.0581 0.0746 0.0568 0.0000 3.0330 0.0581 0.0762 0.0589 0.0000 3.0989 0.0581 0.0778 0.0610 0.0000 3.1648 0.0581 0.0794 0.0629 0.0000 3.2308 0.0581 0.0810 0.0649 0.0000 3.2967 0.0581 0.0826 0.0668 0.0000 3.3626 0.0581 0.0842 0.0686 0.0000 3.4286 0.0581 0.0858 0.0704 0.0000 3.4945 0.0581 0.0874 0.0721 0.0000 3.5604 0.0581 0.0889 0.0738 0.0000 3.6264 0.0581 0.0905 0.0755 0.0000 3.6923 0.0581 0.0921 0.0771 0.0000 3.7582 0.0581 0.0937 0.0787 0.0000 3.8242 0.0581 0.0953 0.0802 0.0000 3.8901 0.0581 0.0969 0.0818 0.0000 3.9560 0.0581 0.0985 0.0833 0.0000 4.0220 0.0581 0.1001 0.0847 0.0000 4.0879 0.0581 0.1017 0.0862 0.0000 4.1538 0.0581 0.1032 0.0876 0.0000 4.2198 0.0581 0.1048 0.0890 0.0000 4.2857 0.0581 0.1064 0.0904 0.0000 4.3516 0.0581 0.1080 0.0918 0.0000 4.4176 0.0581 0.1096 0.0931 0.0000 4.4835 0.0581 0.1112 0.0945 0.0000 4.5000 0.0581 0.1116 0.1295 0.0000 Surface retention BB Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) To Amended(cfs) Wetted Surface 4.5000 0.0581 0.1116 0.0000 0.7029 0.0000 Drainage Report Lindsay Project 1 06-Feb-2026 13-34 4.5659 0.0598 0.1155 0.0000 0.7029 0.0000 4.6319 0.0614 0.1195 0.0000 0.7647 0.0000 4.6978 0.0631 0.1236 0.0000 0.7956 0.0000 4.7637 0.0648 0.1278 0.0000 0.8265 0.0000 4.8297 0.0665 0.1321 0.0000 0.8574 0.0000 4.8956 0.0682 0.1366 0.0000 0.8883 0.0000 4.9615 0.0699 0.1411 0.0000 0.9192 0.0000 5.0275 0.0717 0.1458 0.0000 0.9501 0.0000 5.0934 0.0734 0.1506 0.0000 0.9810 0.0000 5.1593 0.0751 0.1555 0.0000 1.0119 0.0000 5.2253 0.0769 0.1605 0.0000 1.0428 0.0000 5.2912 0.0786 0.1656 0.0035 1.0737 0.0000 5.3571 0.0804 0.1709 0.0146 1.1046 0.0000 5.4231 0.0822 0.1762 0.0300 1.1355 0.0000 5.4890 0.0839 0.1817 0.0486 1.1664 0.0000 5.5549 0.0857 0.1873 0.1885 1.1973 0.0000 5.6209 0.0875 0.1930 0.4934 1.2282 0.0000 5.6868 0.0893 0.1988 0.8781 1.2591 0.0000 5.7527 0.0911 0.2048 1.2863 1.2900 0.0000 5.8187 0.0929 0.2108 1.6617 1.3209 0.0000 5.8846 0.0947 0.2170 1.9574 1.3518 0.0000 5.9505 0.0965 0.2233 2.1548 1.3827 0.0000 6.0000 0.0979 0.2281 2.3156 1.4058 0.0000 Name Surface retention BB Element Flows To: Outlet 1 Outlet 2 Surface retention 3 Bioretention BB Name Vault 1 Width 36.9894699121155 ft.--> Vault is 1,370-sf open volume, or 3,423-sf Length 36.9894699121155 ft. w/ 0.40 porosity of rock Depth: 9 ft. Discharge Structure Riser Height: 8 ft. Riser Diameter: 18 in. Notch Type: Rectangular Notch Width: 0.011 ft. Notch Height: 3.979 ft. Orifice 1 Diameter: 1.42 in. Elevation: 0 ft. Element Flows To: Outlet 1 Outlet 2 Vault Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.031 0.000 0.000 0.000 0.1000 0.031 0.003 0.017 0.000 0.2000 0.031 0.006 0.024 0.000 0.3000 0.031 0.009 0.030 0.000 0.4000 0.031 0.012 0.034 0.000 0.5000 0.031 0.015 0.038 0.000 0.6000 0.031 0.018 0.042 0.000 0.7000 0.031 0.022 0.045 0.000 0.8000 0.031 0.025 0.048 0.000 Drainage Report Lindsay Project 1 06-Feb-2026 13-35 0.9000 0.031 0.028 0.051 0.000 1.0000 0.031 0.031 0.054 0.000 1.1000 0.031 0.034 0.057 0.000 1.2000 0.031 0.037 0.059 0.000 1.3000 0.031 0.040 0.062 0.000 1.4000 0.031 0.044 0.064 0.000 1.5000 0.031 0.047 0.067 0.000 1.6000 0.031 0.050 0.069 0.000 1.7000 0.031 0.053 0.071 0.000 1.8000 0.031 0.056 0.073 0.000 1.9000 0.031 0.059 0.075 0.000 2.0000 0.031 0.062 0.077 0.000 2.1000 0.031 0.066 0.079 0.000 2.2000 0.031 0.069 0.081 0.000 2.3000 0.031 0.072 0.083 0.000 2.4000 0.031 0.075 0.084 0.000 2.5000 0.031 0.078 0.086 0.000 2.6000 0.031 0.081 0.088 0.000 2.7000 0.031 0.084 0.089 0.000 2.8000 0.031 0.087 0.091 0.000 2.9000 0.031 0.091 0.093 0.000 3.0000 0.031 0.094 0.094 0.000 3.1000 0.031 0.097 0.096 0.000 3.2000 0.031 0.100 0.097 0.000 3.3000 0.031 0.103 0.099 0.000 3.4000 0.031 0.106 0.100 0.000 3.5000 0.031 0.109 0.102 0.000 3.6000 0.031 0.113 0.103 0.000 3.7000 0.031 0.116 0.105 0.000 3.8000 0.031 0.119 0.106 0.000 3.9000 0.031 0.122 0.108 0.000 4.0000 0.031 0.125 0.109 0.000 4.1000 0.031 0.128 0.111 0.000 4.2000 0.031 0.131 0.114 0.000 4.3000 0.031 0.135 0.118 0.000 4.4000 0.031 0.138 0.122 0.000 4.5000 0.031 0.141 0.127 0.000 4.6000 0.031 0.144 0.131 0.000 4.7000 0.031 0.147 0.136 0.000 4.8000 0.031 0.150 0.141 0.000 4.9000 0.031 0.153 0.146 0.000 5.0000 0.031 0.157 0.150 0.000 5.1000 0.031 0.160 0.156 0.000 5.2000 0.031 0.163 0.162 0.000 5.3000 0.031 0.166 0.168 0.000 5.4000 0.031 0.169 0.174 0.000 5.5000 0.031 0.172 0.197 0.000 5.6000 0.031 0.175 0.206 0.000 5.7000 0.031 0.179 0.214 0.000 5.8000 0.031 0.182 0.223 0.000 5.9000 0.031 0.185 0.232 0.000 6.0000 0.031 0.188 0.241 0.000 6.1000 0.031 0.191 0.251 0.000 6.2000 0.031 0.194 0.260 0.000 6.3000 0.031 0.197 0.270 0.000 6.4000 0.031 0.201 0.280 0.000 6.5000 0.031 0.204 0.290 0.000 6.6000 0.031 0.207 0.300 0.000 Drainage Report Lindsay Project 1 06-Feb-2026 13-36 6.7000 0.031 0.210 0.311 0.000 6.8000 0.031 0.213 0.321 0.000 6.9000 0.031 0.216 0.332 0.000 7.0000 0.031 0.219 0.343 0.000 7.1000 0.031 0.223 0.354 0.000 7.2000 0.031 0.226 0.366 0.000 7.3000 0.031 0.229 0.377 0.000 7.4000 0.031 0.232 0.389 0.000 7.5000 0.031 0.235 0.400 0.000 7.6000 0.031 0.238 0.412 0.000 7.7000 0.031 0.241 0.424 0.000 7.8000 0.031 0.245 0.437 0.000 7.9000 0.031 0.248 0.449 0.000 8.0000 0.031 0.251 0.461 0.000 8.1000 0.031 0.254 0.965 0.000 8.2000 0.031 0.257 1.868 0.000 8.3000 0.031 0.260 2.966 0.000 8.4000 0.031 0.263 4.097 0.000 8.5000 0.031 0.267 5.105 0.000 8.6000 0.031 0.270 5.868 0.000 8.7000 0.031 0.273 6.361 0.000 8.8000 0.031 0.276 6.807 0.000 8.9000 0.031 0.279 7.193 0.000 9.0000 0.031 0.282 7.557 0.000 9.1000 0.031 0.285 7.904 0.000 9.2000 0.000 0.000 8.236 0.000 ANALYSIS RESULTS Stream Protection Duration Predeveloped Landuse Totals for POC #1 Total Pervious Area:10.16 Total Impervious Area:O Mitigated Landuse Totals for POC #1 Total Pervious Area:3.85 Total Impervious Area:3.46 Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.219642 5 year 0.323011 10 year 0.377094 25 year 0.431 50 year 0.462572 100 year 0.488299 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.164971 Drainage Report Lindsay Project 1 06-Feb-2026 13-37 5 year 0.316261 10 year 0.473887 25 year 0.767572 50 year 1.078791 100 year 1.494415 Stream Protection Duration POC #1 The Facility PASSED The Facility PASSED. Flow(cfs) Predev Mit Percentage Pass/Fail 0.1098 56482 53889 95 Pass 0.1134 51566 46457 90 Pass 0.1169 48274 42917 88 Pass 0.1205 44260 38431 86 Pass 0.1241 40644 34588 85 Pass 0.1276 38243 32127 84 Pass 0.1312 35342 28835 81 Pass 0.1348 33261 26743 80 Pass 0.1383 30757 24316 79 Pass 0.1419 28989 22560 77 Pass 0.1455 26842 20225 75 Pass 0.1490 24943 18090 72 Pass 0.1526 23584 16856 71 Pass 0.1561 21899 15508 70 Pass 0.1597 20765 14627 70 Pass 0.1633 19306 13537 70 Pass 0.1668 18271 12805 70 Pass 0.1704 17000 11836 69 Pass 0.1740 16080 10999 68 Pass 0.1775 14985 10344 69 Pass 0.1811 13966 10041 71 Pass 0.1846 13240 9832 74 Pass 0.1882 12359 9579 77 Pass 0.1918 11753 9414 80 Pass 0.1953 11049 9182 83 Pass 0.1989 10509 8995 85 Pass 0.2025 9876 8549 86 Pass 0.2060 9215 8175 88 Pass 0.2096 8797 7911 89 Pass 0.2132 8280 7575 91 Pass 0.2167 7889 7333 92 Pass 0.2203 7393 6969 94 Pass 0.2238 7074 6716 94 Pass 0.2274 6667 6419 96 Pass 0.2310 6413 6199 96 Pass 0.2345 6105 5896 96 Pass 0.2381 5813 5621 96 Pass 0.2417 5588 5396 96 Pass 0.2452 5325 5117 96 Pass 0.2488 5133 4905 95 Pass 0.2523 4890 4635 94 Pass 0.2559 4713 4433 94 Pass 0.2595 4455 4111 92 Pass 0.2630 4201 3783 90 Pass 0.2666 4038 3484 86 Pass Drainage Report Lindsay Project 1 06-Feb-2026 13-38 0.2702 3853 3003 77 Pass 0.2737 3723 2773 74 Pass 0.2773 3544 2581 72 Pass 0.2809 3425 2462 71 Pass 0.2844 3282 2301 70 Pass 0.2880 3178 2189 68 Pass 0.2915 3065 2070 67 Pass 0.2951 2963 1969 66 Pass 0.2987 2898 1908 65 Pass 0.3022 2799 1833 65 Pass 0.3058 2735 1777 64 Pass 0.3094 2642 1718 65 Pass 0.3129 2524 1671 66 Pass 0.3165 2430 1615 66 Pass 0.3200 2319 1555 67 Pass 0.3236 2220 1511 68 Pass 0.3272 2104 1442 68 Pass 0.3307 2022 1399 69 Pass 0.3343 1913 1341 70 Pass 0.3379 1856 1301 70 Pass 0.3414 1769 1262 71 Pass 0.3450 1714 1232 71 Pass 0.3486 1642 1193 72 Pass 0.3521 1571 1154 73 Pass 0.3557 1517 1121 73 Pass 0.3592 1446 1091 75 Pass 0.3628 1397 1058 75 Pass 0.3664 1327 1021 76 Pass 0.3699 1276 995 77 Pass 0.3735 1226 962 78 Pass 0.3771 1168 929 79 Pass 0.3806 1123 909 80 Pass 0.3842 1066 877 82 Pass 0.3877 1036 852 82 Pass 0.3913 993 822 82 Pass 0.3949 960 795 82 Pass 0.3984 924 762 82 Pass 0.4020 891 734 82 Pass 0.4056 827 699 84 Pass 0.4091 756 672 88 Pass 0.4127 725 650 89 Pass 0.4163 688 614 89 Pass 0.4198 654 590 90 Pass 0.4234 612 565 92 Pass 0.4269 573 541 94 Pass 0.4305 531 519 97 Pass 0.4341 485 502 103 Pass 0.4376 458 477 104 Pass 0.4412 427 445 104 Pass 0.4448 401 430 107 Pass 0.4483 367 402 109 Pass 0.4519 356 389 109 Pass 0.4554 333 366 109 Pass 0.4590 317 343 108 Pass 0.4626 301 328 108 Pass Water Quality BMP Flow and Volume for POC #1 Drainage Report Lindsay Project 1 06-Feb-2026 13-39 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. LID Report LID Technique Used for Total Volume Volume Infiltration Cumulative Percent Water Quality Percent Comment Treatment? Needs Through Volume Volume Volume Water Quality Treatment Facility (ac-ft.) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit Vault 1 POC N 0.00 N 0.00 retention 3 N 0.00 N 0.00 retention BB N 0.00 N 0.00 retention A N 0.00 N 0.00 Total Volume Infiltrated 0.00 0.00 0.00 0.00 0.00 0% No Treat. Credit Compliance with LID Standard 8 Duration Analysis Result = Passed 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 © by Clear Creek Solutions, Inc. 2005-2026; All Rights Reserved. 13.3 Northeast Basin WWHM2012 PROJECT REPORT Project Name: AV test WQ b4 Vlt 80.25x39 Site Name: Lindsay NE Basin Vault Site Address: City Report Date: 1/9/2025 MGS Regoin Puget East Data Start 1901/10/1 Data End : 2058/09/30 DOT Data Number: 05 Version Date: 2023/03/31 Version : 4 .2 .19 Low Flow Threshold for POC 1 50 Percent of the 2 Year High Flow Threshold for POC 1: 50 year PREDEVELOPED LAND USE Drainage Report Lindsay Project 1 06-Feb-2026 13-40 Name : Basin 1 Bypass: No Groundwater: No Pervious Land Use acre C, Forest, Flat 4.4 Pervious Total 4.4 Impervious Land Use acre ROADS FLAT 0.13 Impervious Total 0.13 Basin Total 4.53 Element Flows To: Surface Interflow Groundwater MITIGATED LAND USE Name : Upstream Bypass: Yes GroundWater: No Pervious Land Use acre C. Forest, Flat 1.36 Pervious Total 1.36 Impervious Land Use acre Impervious Total 0 Basin Total 1.36 Element Flows To: Surface Interflow Groundwater Vault 1 Name : Basin 2 Bypass: No GroundWater: No Pervious Land Use acre C. Pasture, Flat 1.41 Pervious Total 1.41 Impervious Land Use acre ROOF TOPS FLAT 1 Impervious Total 1 Basin Total 2.41 Element Flows To: Surface Interflow Groundwater Vault 1 Vault 1 Name Vault 1 Drainage Report Lindsay Project 1 06-Feb-2026 13-41 Width 38.03 ft. Length 80.25 ft. Depth: 7 ft. Discharge Structure Riser Height: 6 ft. Riser Diameter: 18 in. Orifice 1 Diameter: 1.14 in. Elevation: 0 ft. Orifice 2 Diameter: 1.9 in. Elevation: 3.95 ft. Orifice 3 Diameter: 1.1 in. Elevation: 4.97 ft. Element Flows To: Outlet 1 Outlet 2 Vault Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.070 0.000 0.000 0.000 0.0778 0.070 0.005 0.009 0.000 0.1556 0.070 0.010 0.013 0.000 0.2333 0.070 0.016 0.017 0.000 0.3111 0.070 0.021 0.019 0.000 0.3889 0.070 0.027 0.022 0.000 0.4667 0.070 0.032 0.024 0.000 0.5444 0.070 0.038 0.026 0.000 0.6222 0.070 0.043 0.027 0.000 0.7000 0.070 0.049 0.029 0.000 0.7778 0.070 0.054 0.031 0.000 0.8556 0.070 0.059 0.032 0.000 0.9333 0.070 0.065 0.034 0.000 1.0111 0.070 0.070 0.035 0.000 1.0889 0.070 0.076 0.036 0.000 1.1667 0.070 0.081 0.038 0.000 1.2444 0.070 0.087 0.039 0.000 1.3222 0.070 0.092 0.040 0.000 1.4000 0.070 0.098 0.041 0.000 1.4778 0.070 0.103 0.042 0.000 1.5556 0.070 0.109 0.044 0.000 1.6333 0.070 0.114 0.045 0.000 1.7111 0.070 0.119 0.046 0.000 1.7889 0.070 0.125 0.047 0.000 1.8667 0.070 0.130 0.048 0.000 1.9444 0.070 0.136 0.049 0.000 2.0222 0.070 0.141 0.050 0.000 2.1000 0.070 0.147 0.051 0.000 2.1778 0.070 0.152 0.052 0.000 2.2556 0.070 0.158 0.053 0.000 2.3333 0.070 0.163 0.053 0.000 2.4111 0.070 0.168 0.054 0.000 2.4889 0.070 0.174 0.055 0.000 2.5667 0.070 0.179 0.056 0.000 2.6444 0.070 0.185 0.057 0.000 2.7222 0.070 0.190 0.058 0.000 2.8000 0.070 0.196 0.059 0.000 2.8778 0.070 0.201 0.059 0.000 2.9556 0.070 0.207 0.060 0.000 3.0333 0.070 0.212 0.061 0.000 3.1111 0.070 0.218 0.062 0.000 3.1889 0.070 0.223 0.063 0.000 Drainage Report Lindsay Project 1 06-Feb-2026 13-42 3.2667 0.070 0.228 0.063 0.000 3.3444 0.070 0.234 0.064 0.000 3.4222 0.070 0.239 0.065 0.000 3.5000 0.070 0.245 0.066 0.000 3.5778 0.070 0.250 0.066 0.000 3.6556 0.070 0.256 0.067 0.000 3.7333 0.070 0.261 0.068 0.000 3.8111 0.070 0.267 0.068 0.000 3.8889 0.070 0.272 0.069 0.000 3.9667 0.070 0.277 0.082 0.000 4.0444 0.070 0.283 0.101 0.000 4.1222 0.070 0.288 0.112 0.000 4.2000 0.070 0.294 0.121 0.000 4.2778 0.070 0.299 0.129 0.000 4.3556 0.070 0.305 0.136 0.000 4.4333 0.070 0.310 0.142 0.000 4.5111 0.070 0.316 0.148 0.000 4.5889 0.070 0.321 0.153 0.000 4.6667 0.070 0.327 0.159 0.000 4.7444 0.070 0.332 0.164 0.000 4.8222 0.070 0.337 0.168 0.000 4.9000 0.070 0.343 0.173 0.000 4.9778 0.070 0.348 0.180 0.000 5.0556 0.070 0.354 0.191 0.000 5.1333 0.070 0.359 0.199 0.000 5.2111 0.070 0.365 0.206 0.000 5.2889 0.070 0.370 0.213 0.000 5.3667 0.070 0.376 0.219 0.000 5.4444 0.070 0.381 0.224 0.000 5.5222 0.070 0.386 0.230 0.000 5.6000 0.070 0.392 0.235 0.000 5.6778 0.070 0.397 0.240 0.000 5.7556 0.070 0.403 0.245 0.000 5.8333 0.070 0.408 0.250 0.000 5.9111 0.070 0.414 0.254 0.000 5.9889 0.070 0.419 0.259 0.000 6.0667 0.070 0.425 0.537 0.000 6.1444 0.070 0.430 1.137 0.000 6.2222 0.070 0.435 1.909 0.000 6.3000 0.070 0.441 2.777 0.000 6.3778 0.070 0.446 3.666 0.000 6.4556 0.070 0.452 4.500 0.000 6.5333 0.070 0.457 5.212 0.000 6.6111 0.070 0.463 5.760 0.000 6.6889 0.070 0.468 6.145 0.000 6.7667 0.070 0.474 6.505 0.000 6.8444 0.070 0.479 6.816 0.000 6.9222 0.070 0.485 7.113 0.000 7.0000 0.070 0.490 7.397 0.000 7.0778 0.070 0.495 7.671 0.000 7.1556 0.000 0.000 7.936 0.000 Name Bioretention 1 Bottom Length: 100.00 ft. Bottom Width: 1.00 ft. Material thickness of first layer: 1.5 Material type for first layer: SMMWW 12 in/hr Drainage Report Lindsay Project 1 06-Feb-2026 13-43 Material thickness of second layer: 0.5 Material type for second layer: Sand Material thickness of third layer: 0.5 Material type for third layer: GRAVEL Underdrain used Underdrain Diameter (feet) : 0.5 Orifice Diameter (in. ) : 6 Offset (in. ) : 0 Flow Through Underdrain (ac-ft. ) : 209.75 Total Outflow (ac-ft. ) : 225.021 Percent Through Underdrain: 93.21 Discharge Structure Riser Height: 0.5 ft. Riser Diameter: 6 in. Element Flows To: Outlet 1 Outlet 2 Vault 1 Bioretention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.0023 0.0000 0.0000 0.0000 0.0385 0.0023 0.0000 0.0000 0.0000 0.0769 0.0023 0.0001 0.0000 0.0000 0.1154 0.0023 0.0001 0.0000 0.0000 0.1538 0.0023 0.0002 0.0000 0.0000 0.1923 0.0023 0.0002 0.0000 0.0000 0.2308 0.0023 0.0002 0.0000 0.0000 0.2692 0.0023 0.0003 0.0000 0.0000 0.3077 0.0023 0.0003 0.0000 0.0000 0.3462 0.0023 0.0004 0.0002 0.0000 0.3846 0.0023 0.0004 0.0003 0.0000 0.4231 0.0023 0.0004 0.0004 0.0000 0.4615 0.0023 0.0005 0.0005 0.0000 0.5000 0.0023 0.0005 0.0007 0.0000 0.5385 0.0023 0.0006 0.0009 0.0000 0.5769 0.0023 0.0006 0.0009 0.0000 0.6154 0.0023 0.0006 0.0011 0.0000 0.6538 0.0023 0.0007 0.0014 0.0000 0.6923 0.0023 0.0007 0.0015 0.0000 0.7308 0.0023 0.0008 0.0016 0.0000 0.7692 0.0023 0.0008 0.0020 0.0000 0.8077 0.0023 0.0008 0.0024 0.0000 0.8462 0.0023 0.0009 0.0025 0.0000 0.8846 0.0023 0.0009 0.0028 0.0000 0.9231 0.0023 0.0010 0.0032 0.0000 0.9615 0.0023 0.0010 0.0037 0.0000 1.0000 0.0023 0.0010 0.0037 0.0000 1.0385 0.0023 0.0011 0.0043 0.0000 1.0769 0.0023 0.0011 0.0049 0.0000 1.1154 0.0023 0.0012 0.0052 0.0000 1.1538 0.0023 0.0012 0.0055 0.0000 1.1923 0.0023 0.0013 0.0062 0.0000 1.2308 0.0023 0.0013 0.0069 0.0000 1.2692 0.0023 0.0013 0.0071 0.0000 1.3077 0.0023 0.0014 0.0077 0.0000 1.3462 0.0023 0.0014 0.0086 0.0000 Drainage Report Lindsay Project 1 06-Feb-2026 13-44 1.3846 0.0023 0.0015 0.0093 0.0000 1.4231 0.0023 0.0015 0.0095 0.0000 1.4615 0.0023 0.0015 0.0104 0.0000 1.5000 0.0023 0.0016 0.0114 0.0000 1.5385 0.0023 0.0016 0.0119 0.0000 1.5769 0.0023 0.0016 0.0125 0.0000 1.6154 0.0023 0.0017 0.0136 0.0000 1.6538 0.0023 0.0017 0.0147 0.0000 1.6923 0.0023 0.0017 0.0149 0.0000 1.7308 0.0023 0.0018 0.0160 0.0000 1.7692 0.0023 0.0018 0.0162 0.0000 1.8077 0.0023 0.0019 0.0173 0.0000 1.8462 0.0023 0.0019 0.0182 0.0000 1.8846 0.0023 0.0019 0.0186 0.0000 1.9231 0.0023 0.0020 0.0200 0.0000 1.9615 0.0023 0.0020 0.0215 0.0000 2.0000 0.0023 0.0020 0.0215 0.0000 2.0385 0.0023 0.0021 0.0215 0.0000 2.0769 0.0023 0.0021 0.0215 0.0000 2.1154 0.0023 0.0021 0.0370 0.0000 2.1538 0.0023 0.0022 0.0370 0.0000 2.1923 0.0023 0.0022 0.0370 0.0000 2.2308 0.0023 0.0022 0.0370 0.0000 2.2692 0.0023 0.0023 0.0370 0.0000 2.3077 0.0023 0.0023 0.0370 0.0000 2.3462 0.0023 0.0024 0.0370 0.0000 2.3846 0.0023 0.0024 0.0370 0.0000 2.4231 0.0023 0.0024 0.0370 0.0000 2.4615 0.0023 0.0025 0.0370 0.0000 2.5000 0.0023 0.0025 0.0370 0.0000 2.5000 0.0023 0.0025 0.0370 0.0000 Surface retention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) To Amended(cfs) Wetted Surface 2.5000 0.0023 0.0025 0.0000 0.0278 0.0000 2.5385 0.0028 0.0026 0.0000 0.0278 0.0000 2.5769 0.0034 0.0027 0.0000 0.0292 0.0000 2.6154 0.0039 0.0029 0.0000 0.0299 0.0000 2.6538 0.0045 0.0030 0.0000 0.0306 0.0000 2.6923 0.0050 0.0032 0.0000 0.0313 0.0000 2.7308 0.0056 0.0034 0.0000 0.0321 0.0000 2.7692 0.0061 0.0036 0.0000 0.0328 0.0000 2.8077 0.0067 0.0039 0.0000 0.0335 0.0000 2.8462 0.0072 0.0041 0.0000 0.0342 0.0000 2.8846 0.0078 0.0044 0.0000 0.0349 0.0000 2.9231 0.0083 0.0047 0.0000 0.0356 0.0000 2.9615 0.0089 0.0051 0.0000 0.0363 0.0000 3.0000 0.0095 0.0054 0.0000 0.0370 0.0000 3.0385 0.0100 0.0058 0.0399 0.0377 0.0000 3.0769 0.0106 0.0062 0.1109 0.0385 0.0000 3.1154 0.0112 0.0066 0.1943 0.0392 0.0000 3.1538 0.0117 0.0071 0.2743 0.0399 0.0000 3.1923 0.0123 0.0075 0.3368 0.0406 0.0000 3.2308 0.0129 0.0080 0.3761 0.0413 0.0000 3.2692 0.0135 0.0085 0.4086 0.0420 0.0000 3.3077 0.0141 0.0090 0.4368 0.0427 0.0000 3.3462 0.0147 0.0096 0.4633 0.0434 0.0000 3.3846 0.0152 0.0102 0.4883 0.0442 0.0000 Drainage Report Lindsay Project 1 06-Feb-2026 13-45 3.4231 0.0158 0.0108 0.5122 0.0449 0.0000 3.4615 0.0164 0.0114 0.5349 0.0456 0.0000 3.5000 0.0170 0.0120 0.5568 0.0463 0.0000 Name Surface retention 1 Element Flows To: Outlet 1 Outlet 2 Vault 1 Bioretention 1 Name : Basin 3 Bypass: Yes Groundwater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.13 Impervious Total 0.13 Basin Total 0.13 Element Flows To: Surface Interflow Groundwater Vault 1 Name Basin 4 Bypass: No Groundwater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.3 DRIVEWAYS FLAT 0.13 SIDEWALKS FLAT 0.09 Impervious Total 0.52 Basin Total 0.52 Element Flows To: Surface Interflow Groundwater Surface retention 1 Surface retention 1 ANALYSIS RESULTS Stream Protection Duration Drainage Report Lindsay Project 1 06-Feb-2026 13-46 Predeveloped Landuse Totals for POC #1 Total Pervious Area:4.4 Total Impervious Area:0.13 Mitigated Landuse Totals for POC #1 Total Pervious Area:2.77 Total Impervious Area:1.65 Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.107737 5 year 0.164445 10 year 0.207058 25 year 0.266639 50 year 0.315212 100 year 0.367401 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.071559 5 year 0. 114541 10 year 0.15343 25 year 0.21742 50 year 0.278064 100 year 0.351924 Stream Protection Duration POC #1 The Facility PASSED The Facility PASSED. Flow(cfs) Predev Mit Percentage Pass/Fail 0.0539 11971 12044 100 Pass 0.0565 10594 9098 85 Pass 0.0591 9397 6649 70 Pass 0.0618 8397 4824 57 Pass 0.0644 7503 3325 44 Pass 0.0671 6708 2298 34 Pass 0.0697 6029 1489 24 Pass 0.0723 5416 1415 26 Pass 0.0750 4884 1359 27 Pass 0.0776 4400 1306 29 Pass 0.0803 3984 1267 31 Pass 0.0829 3584 1230 34 Pass 0.0855 3258 1192 36 Pass 0.0882 2980 1149 38 Pass 0.0908 2710 1113 41 Pass 0.0935 2452 1077 43 Pass 0.0961 2242 1036 46 Pass 0.0987 2070 998 48 Pass 0.1014 1892 971 51 Pass 0.1040 1733 939 54 Pass 0.1067 1603 890 55 Pass 0.1093 1484 860 57 Pass 0.1119 1385 833 60 Pass 0.1146 1302 796 61 Pass 0.1172 1213 770 63 Pass Drainage Report Lindsay Project 1 06-Feb-2026 13-47 0.1199 1125 738 65 Pass 0.1225 1040 706 67 Pass 0.1251 964 670 69 Pass 0.1278 898 639 71 Pass 0.1304 839 605 72 Pass 0.1331 798 572 71 Pass 0.1357 751 542 72 Pass 0.1383 710 513 72 Pass 0.1410 664 480 72 Pass 0.1436 615 450 73 Pass 0.1463 580 419 72 Pass 0.1489 544 394 72 Pass 0.1515 507 370 72 Pass 0.1542 471 347 73 Pass 0.1568 439 321 73 Pass 0.1595 414 297 71 Pass 0.1621 384 278 72 Pass 0.1647 366 259 70 Pass 0.1674 339 241 71 Pass 0.1700 319 223 69 Pass 0.1727 302 206 68 Pass 0.1753 280 190 67 Pass 0.1779 261 180 68 Pass 0.1806 247 174 70 Pass 0.1832 229 165 72 Pass 0.1859 212 159 75 Pass 0.1885 192 148 77 Pass 0.1911 179 143 79 Pass 0.1938 158 136 86 Pass 0.1964 147 130 88 Pass 0.1991 135 124 91 Pass 0.2017 125 116 92 Pass 0.2043 113 110 97 Pass 0.2070 102 104 101 Pass 0.2096 93 95 102 Pass 0.2123 86 89 103 Pass 0.2149 79 79 100 Pass 0.2175 71 72 101 Pass 0.2202 61 66 108 Pass 0.2228 58 60 103 Pass 0.2255 52 52 100 Pass 0.2281 49 50 102 Pass 0.2307 43 44 102 Pass 0.2334 39 38 97 Pass 0.2360 37 33 89 Pass 0.2387 32 27 84 Pass 0.2413 27 25 92 Pass 0.2439 27 22 81 Pass 0.2466 26 18 69 Pass 0.2492 23 16 69 Pass 0.2519 21 13 61 Pass 0.2545 19 10 52 Pass 0.2571 17 10 58 Pass 0.2598 16 9 56 Pass 0.2624 15 9 60 Pass 0.2651 13 8 61 Pass 0.2677 12 8 66 Pass 0.2703 12 8 66 Pass Drainage Report Lindsay Project 1 06-Feb-2026 13-48 0.2730 12 8 66 Pass 0.2756 11 8 72 Pass 0.2783 11 8 72 Pass 0.2809 11 8 72 Pass 0.2835 11 7 63 Pass 0.2862 11 6 54 Pass 0.2888 10 6 60 Pass 0.2915 10 6 60 Pass 0.2941 10 6 60 Pass 0.2967 10 6 60 Pass 0.2994 10 6 60 Pass 0.3020 9 6 66 Pass 0.3047 9 6 66 Pass 0.3073 8 6 75 Pass 0.3099 8 6 75 Pass 0.3126 7 6 85 Pass 0.3152 7 5 71 Pass 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. LID Report LID Technique Used for Total Volume Volume Infiltration Cumulative Percent Water Quality Percent Comment Treatment? Needs Through Volume Volume Volume Water Quality Treatment Facility (ac-ft.) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit Vault 1 POC N 801.55 N 0.00 retention 1 N 204.77 N 0.00 Total Volume Infiltrated 1006.32 0.00 0.00 0.00 0.00 0% No Treat. Credit Compliance with LID Standard 8 Duration Analysis Result = Passed Perind and Impind Changes No changes have been made. 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 Q by : Clear Creek Solutions, Inc. 2005-2025; All Rights Reserved. Drainage Report Lindsay Project 1 06-Feb-2026 13-49