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REV1 APPROVED STM RESUB 1+PLN2012-0021+Drainage Report+Recd 9-14-22Drainage Report - Revision Bill Ritter SP for Vector One,_LLC SITE LOCATION: 8364 Olympic View Dr. Edmonds, WA 980260 Tax Parcel: 27041800101000 Prepared by: Joseph M. Smeby, P.E. Job No: 16-0915 November, 2016 Revision: July 2022 Sept 2022 •11 11111 11 1 • ITEM TABLEOF CONTENTS..................................................................................................1 LISTOF FIGURES.........................................................................................................a 2 1. INTRODUCTION &SITE CLASSIFICATION..............................................................3 2. PREPARATION OF STORMWATER SITE PLAN ....................................................... 4 3. SWPPP NARRATIVE..................................................................................................5 A. RISK ASSESSMENT. . 8 a a 9 a a a 8 a a I a a 8 a 9 v 9 v a a a 0 a 9 a I 1 9 9 a a s a s 0 s a ff a a a a a 0 a w a a a a w a m 0 a a A a R 0 m m * 6 a 0 a a a 9 2 6 B. SWPPP MINIMUM ELEMENTS. . I I 1 9 9 a a 0 d 9 4 a * 1 0 8 a 0 0 a a a I a a 9 a a a a a 4 9 9 4 a v I a a m a a I a 0 0 A % a a m a 9 a 97 4. SOURCE CONTROL.................................................................................................. 8 5. PRESERVATION OF NATURAL DRAINAGE SYSTEM..............................................8 6. ON -SITE STORMWATER MANAGEMENT................................................................. 9 7. RUNOFF TREATMENT..........................................:................................................... 9 8. FLOW CONTROL.....................................................................................................10 9. WETLANDS PROTECTION......................................................................................11 10. MAINTENANCE AND OPERATIONS MANUAL......................................................11 11. OFFSITE ANALYSIS AND MITIGATION.................................................................11 12. FINANCIAL LIABILITY............................................................................................11 Bill Ritter SP 16-0915 Sept 2022 Page 1 LIST OF FIGURES ITEM FIGURE1 VICINITY MAP ....................................................................................... 12 FIGURE 2 EXISTING DRAINAGE BASIN MAP ...................................................... 13 FIGURE 3 DEVELOPED DRAINAGE BASIN MAP .................................................14 FIGURE 4 SNOHOMISH COUNTY SOILS MAP ..................................................... 15 FIGURE 5 UPSTREAM/DOWNSTREAM TRIBUTARY AREA MAP ........................16 Bill' Ritter SP 16-0915 Sept 2022 Page 2 This report has been prepared to revise the previously approved drainage design for this project. The original design included a stormfilter CB (still used in this design) along with an oversized pipe detention storage for the improved site runoff mitigation. The new design will utilize the permeable soils beneath the site for full infiltration of the new impervious surfaces and most proposed landscaping. The project Geotech (AESI) has provided a recommended long-term infiltration rate and verified that there is no issue with the use of infiltration even though this project is at the edge of a mapped erosion hazard area. This document is intended to provide engineering information necessary to support the construction permit application submittal to the City of Edmonds for the three -lot short plat proposed on this site. The site covers 1.29 acres, with approximately 14,600 sf allowed to be disturbed. Lot C will not be disturbed as a result of this project so the area of disturbance will be on future lots A & B along with some work within the Olympic View Drive R/W. An existing access is located along the east side of the existing parcel serving the existing SFR on future Lot C along with some adjacent parcels. A new access point will be constructed off of Olympic View Drive in the northwest corner of future Lot A and will serve both Lots A & B. This report is being prepared for the current owners of this project and has been modified to incorporate infiltration into the design as noted above. The downstream, SWPPP and other sections of this report not related to infiltration/flow control and water quality have not been revised as part of this resubmittal. The new infiltration design for the paved access/driveways and roof areas has been completed to meet the Current City and DOE stormwater manuals. The proposed infiltration system design will include two roof downspout infiltration trenches and one trench for the paved access/site runoff. All systems have been sized for full infiltration using the WWHM2012 software. Any overflow from the system or the small portion of paved access that cannot be directed to the on -site infiltration systems will flow west and collect along the east side of the Olympic View roadway in a shallow swale that flows south to an existing CB for collection/conveyance within the City storm system. The site is located at 8364 Olympic View Dr., Edmonds, WA 98020, and in Section 18, Township 27N, Range 4E, Willamette Meridian. See Figure 1 - Vicinity Map. Bill Ritter SP 16-0915 Sept 2022 Page 3 This project was originally reviewed and approved as a Category 2 Small Site Project. However, as noted above the sizing for the drainage mitigation has been done to meet the current City and DOE stormwater standards for infiltration using the WWHM 2012 software. This document is intended to provide the supporting information to justify the sizing of the trenches and detail how the design of the selected BMPs meet the required standards. For this project, geotechnical studies show that water will infiltrate into the soils without creating any unnecessary risk due to the infiltration systems being located along the edge of a mapped erosion hazard area. All the trenches top elevations will be set 2-3' below grade which will ensure the runoff infiltrated will not destabilize the surrounding areas and will be fully extended into the permeable soils beneath the site. Runoff from the two proposed roofs will be directed to individual infiltration trenches and the paved access will be collected by a stormfilter CB before being connected to an infiltration trench. This is discussed in detail in Section 8 of this report and shown on sheets 5 & 6 of the plan set. The following table summarizes the impervious areas proposed and existing for this project: ROOF/PATIO PAVEMENT TOTAL LOT C EXISTING 3,940 sf 5,816 sf 9,816 sf LOT A 2,137 sf 330 sf 2,467 sf LOT B 2,957 sf 759 sf 3,716 sf ACCESS 0 sf 1,511 sf 1,511 sf TOTAL 9,034 sf 8,416 sf 17,450 sf Bill Ritter SP 16-0915 Sept 2022 Page 4 Clearing, grading, and temporary erosion and sediment control plans have been prepared as part of the drainage plan drawings. However, since a construction site is dynamic it will be necessary to reassess the erosion control BMP's during construction and install additional measures when necessary. Proposed temporary measures possible for this project will include the following BMP's: • Installation of stabilized construction entrance. • Retention of Existing Vegetation • Straw mulch, hydroseed or other mulching and planting method to stabilized unworked areas. • Silt fencing if necessary • Inlet protection Permanent measures to reduce or eliminate erosion or water quality degradation will include the following BMP's: • Paving all traffic areas (concrete/asphalt) • Permanent landscaping in pervious areas. • Limiting cut and fill slopes to 2:1 maximum and 3:1 maximum where exposed to standing water. • Routine maintenance and inspection of the grounds and response to developing problems. The listed erosion control BMP's will be engineered for anticipated conditions in compliance with City of Everett and DOE guidelines. With proper installation, maintenance and inspection the proposed BMP's should result in minimal impact to the surrounding environment. The City retains the authority by code to require additional measures should the existing measures prove insufficient. Bill Ritter SP 16-0915 Sept 2022 Page 5 Area proposed to be cleared/worked: 0.34 acres Average slope for the site: 15% Erosion Hazard of Soil Moderate -High Critical Areas downslope No Site is upstream of an ESA Stream No Based on the above information and the fact that the site will retain so much existing vegetation and construction site runoff will filter through the soil, and that if site conditions warrant, additional BMP's can be implemented as corrective measures the Risk Category for this site is Moderate Risk. 1: Mark Clearing Limits The first step in the "Construction Sequence" included on the clearing and grading plan sheets is for the limits of clearing to be flagged and to have construction fencing placed along the limits prior to any other construction activity. 2: Establish Construction Access The SWPPP calls for the proposed construction entrance to be installed as the second step after the staking of clearing limits. A detail is provided on the plans. 3: Control Flow Rates This project will utilize the proposed detention system once it has been constructed. 4: Install Sediment Controls This site and SWPPP proposes to construct/maintain a construction entrance, retained vegetation and silt fencing. These features are intended to minimize the opportunity for sediment to leave the site via stormwater or on vehicles. The construction of these features is one of the first items required in the "Construction Sequence". Mulch will also be used on the exposed soil as necessary to limit erosion. 5: Stabilize Soils The "Construction Sequence" calls for the stabilization of soils that remain unworked for certain lengths of time based on the time of year. Stabilization techniques may include but not limited to mulching, plastic sheeting or hydroseeding, notes have been added to the plan regarding protection for the stock pile area if necessary. A stockpile area has been identified on the SWPPP and is setback a minimum of 20-feet from any down slope property line. 6: Protect Slopes All disturbed slopes on site during construction are required to be protected with mulch or other means as specified in the construction sequence. No concentrated runoff or significant amounts of sheet flow will be directed to new cut or fill slopes during construction. Bill Ritter SP 16-0915 Sept 2022 Page 6 7: Protect Drain Inlets All new catch basins and yard drains will be protected with inlet protection as specified on sheet 2 of the engineering plan set. In addition, the nearest downstream catch basins along the west side of 9th Ave S will receive inlet protection per standard plan E1.3. 8: Stabilize Channels and Outlets No new channels or outlets are proposed for this site. 9: Control Pollutants No outside chemicals are expected to be necessary for the construction of this project. All vehicles working on and around the site would need to meet the State requirements for emissions. 10: Control DeWatering DeWatering is not expected to be necessary for this project. However, the proposed detention system would be available to control the release of any water from construction for disposal. 11: Maintain BMPs The construction supervisor will be responsible for maintaining all BMPs during construction and working with the City to relocate or add BMPs as necessary as site conditions change. 12: Manage the Project It will be the responsibility of the Contractor and Developer to manage this project and coordinate with the City Inspector and Engineer. Inspection and Monitoring: Site inspections shall be done by a person who is knowledgeable in the principles and practices of erosion and sediment control. The person must have skills to first assess the site conditions and construction activities that could impact the quality of stormwater, and second assess the effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. Whenever inspection and/or monitoring reveals that the BMPs identified in the Construction SWPPP are inadequate, due to the actual discharge of or potential to discharge a significant amount of any pollutant, appropriate BMPs or design changes shall be implemented as soon as possible. Maintaining an Updated Construction SWPPP: The construction SWPPP shall be retained on -site or within reasonable access to the site. The SWPPP shall be modified whenever there is a change in the design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the state. The SWPPP shall be modified if, during inspections or investigations conducted by the owner/operator, or the applicable local or state regulatory authority, it is determined that the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. The SWPPP shall be modified as necessary to include additional or modified BMPs designed to correct problems identified. Revisions to the SWPPP shall be completed within seven days following inspection. Bill Ritter SP 16-0915 Sept 2022 Page 7 - • • • Eel • The City of Edmonds Stormwater Supplement and DOE Drainage manual were reviewed to determine if the proposed land -use for this project or construction activities required any site -specific source control BMPs to be constructed. SFR projects are not listed as a proposed use that requires source control. Therefore, no site/development specific source control BMPs are required for this project. The runoff from the on -site basin will be infiltrated into the soils on -site with only a small portion of paved approved in the RM that is too low to be collected by the on -site system draining south in the City RM to an existing CB for collection/conveyance. For this project infiltration is feasible based on the current Geotech's recommendations. Refer to appendix A for a copy of the AESI report documenting the long-term infiltration rate and the recommendation for use of infiltration on this project. This project proposes to construct less than 5,000 sf of new PGIS and is therefore exempt from this requirement, however a Contech Stormfilter is being provided to treat the runoff before infiltrating to protect the infiltration trench from sediment and debris and to protect the groundwater from oils/grease and heavy metals in the runoff from PGIS surfaces. Bill Ritter SP 16-0915 Sept 2022 Page 8 For this project, infiltration trenches have been sized using the WWHM2012. The total new plus replaced impervious surfaces of 8,050 sf will have the runoff mitigated using three separate infiltration trenches. The first trench located at the northwest end of the new access and will collect runoff from the access and any runoff from the adjacent landscaping. Each future SFR on Lots A & B will also have individual infiltration trenches sized for each roof. Refer to the design discussion below. For this project, the infiltration trenches have been sized for three different inputs. Each roof will have an individual system along with one for the paved access, driveways and landscaping that runs on to those surfaces. The three trenches were sized based on the following input: Lot A Roof: 0.05 ac Lot B Roof: 0.07 ac Pavement: 0.06 ac PGIS along with 0.08 ac landscaping The pavement trench does collect some landscaping from the areas south of the paved access and driveways. These numbers are taken from the approved building permit site plans for both the new lots along with the approved SP plans for the access and driveways. Refer to Appendix A for WWHM2012 printouts for the infiltration sizing calculations. Bill Ritter SP 16-0915 Sept 2022 Page 9 9. WETLANDS PROTECTION This project will not impact any wetland on or directly downstream of the site. The Property Owner will be responsible for maintaining the stormwater and landscaping facilities within this development. Included in this manual are checklists for each feature specific to this project. Copies should be made of the checklists as necessary during routine inspections and required maintenance. Specific problems can be recorded along with the appropriate action taken. These checklists are a guide for inspections and maintenance. The frequency of the inspections/maintenance is identified in the left-hand column with the following abbreviations: A = Annual (March or April preferred) M = Monthly S = After Major Storms (Use 1-inch in 24 hours as a guideline) Routine inspections and maintenance will improve the long-term performance of the stormwater facilities. If at any time, you are unsure if a problem exists or how to address a specific problem, contact a Professional Engineer. Refer to Appendix A for a list of each facility to be maintained and the appropriate maintenance checklist. • •I During the site review and downstream site visit for this project it was determined that the properties to the west of this site contain existing SFRs and it is not viable draining in that direction. After further soil analysis, it was also determined that on -site infiltration is feasible. Therefore, site runoff will be directed to three different trenches and any overflow from those systems will be collected along the south side of Olympic Blvd and drain west to an existing CB. The existing drainage system within the R.O.W. consists of a 12" concrete storm system that drains from south to north within the Shell Creek basin. There were no indications from the site observations that any capacity issues exist within this system. The conveyance system was followed to the north for approximately % mile. Therefore, this project's downstream system is completely contained within an engineered pipe conveyance system which was not observed to have any drainage problems. 12. FINANCIAL LIABILITY Since this is a single-family residential project and it does not fall within a Critical Area, per the City of Edmonds Stormwater Supplement no bonds or other financial guarantees are required. A KC engineering cost estimate worksheet is being provided to the City for Construction bonds. Bill Ritter SP 16-0915 Sept 2022 Page 10 APPENDIX A STORMWATER CALCULATIONS BILL RITTER SP 16-0915 Sept. 2022 Page -14 WWH? PROJECT General Model Information Project Name: site inf only - SPLIT Site Name: RITTER SP Site Address: City: EDMONDS Report Date: 7/21/2022 Gage: Everett Data Start: 1948/10/01 Data End: 2009/09/30 Timestep: 15 Minute Precip Scale: 0.800 Version Date: 2021/08/18 Version: 4.2.18 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year site inf only - SPLIT 7/21/2022 11:57:26 AM Page 2 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Steep 0.3 Pervious Total 0.3 Impervious Land Use acre Impervious Total 0 Basin Total 0.3 Element Flows To: Surface Interflow Groundwater site inf only - SPLIT 7/21/2022 11:57:26 AM Page 3 Mitigated Land Use LOWER Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Mod 0.12 Pervious Total 0.12 Impervious Land Use acre DRIVEWAYS MOD 0.06 Impervious Total 0.06 Basin Total 0.18 Element Flows To: Surface Interflow Groundwater Gravel Trench Bed 1 Gravel Trench Bed 1 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 4 Lot B - Roof and Landscaping Bypass: No GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.07 Impervious Total 0.07 Basin Total 0.07 Element Flows To: Surface Interflow Groundwater Gravel Trench Bed 2 Gravel Trench Bed 2 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 5 Lot A Roof Bypass: No GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.055 Impervious Total 0.055 Basin Total 0.055 Element Flows To: Surface Interflow Groundwater Gravel Trench Bed 3 Gravel Trench Bed 3 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 6 Routing Elements Predeveloped Routing site inf only - SPLIT 7/21/2022 11:57:26 AM Page 7 Mitigated Routing Gravel Trench Bed 1 Bottom Length: 38.00 ft. Bottom Width: 8.00 ft. Trench bottom slope 1: 0 To 1 Trench Left side slope 0: 0 To 1 Trench right side slope 2: 0 To 1 Material thickness of first layer: 4 Pour Space of material for first layer: 0.4 Material thickness of second layer: 0 Pour Space of material for second layer: 0 Material thickness of third layer: 0 Pour Space of material for third layer: 0 Infiltration On Infiltration rate: 1.3 Infiltration safety factor: 1 Total Volume Infiltrated (ac-ft.): 12.737 Total Volume Through Riser (ac-ft.): 0 Total Volume Through Facility (ac-ft.): 12.737 Percent Infiltrated: 100 Total Precip Applied to Facility: 0 Total Evap From Facility: 0 Discharge Structure Riser Height: 4 ft. Riser Diameter: 8 in. Element Flows To: Outlet 1 Outlet 2 Channel 1 Gravel Trench Bed Hydraulic Table Stage(feet) Area(ac.) Volume(ac-%) Discharge(cfs) Infilt(cfs) 0.0000 0.007 0.000 0.000 0.000 0.0556 0.007 0.000 0.000 0.009 0.1111 0.007 0.000 0.000 0.009 0.1667 0.007 0.000 0.000 0.009 0.2222 0.007 0.000 0.000 0.009 0.2778 0.007 0.000 0.000 0.009 0.3333 0.007 0.000 0.000 0.009 0.3889 0.007 0.001 0.000 0.009 0.4444 0.007 0.001 0.000 0.009 0.5000 0.007 0.001 0.000 0.009 0.5556 0.007 0.001 0.000 0.009 0.6111 0.007 0.001 0.000 0.009 0.6667 0.007 0.001 0.000 0.009 0.7222 0.007 0.002 0.000 0.009 0.7778 0.007 0.002 0.000 0.009 0.8333 0.007 0.002 0.000 0.009 0.8889 0.007 0.002 0.000 0.009 0.9444 0.007 0.002 0.000 0.009 1.0000 0.007 0.002 0.000 0.009 1.0556 0.007 0.002 0.000 0.009 1.1111 0.007 0.003 0.000 0.009 1.1667 0.007 0.003 0.000 0.009 1.2222 0.007 0.003 0.000 0.009 1.2778 0.007 0.003 0.000 0.009 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 8 1.3333 0.007 0.003 0.000 0.009 1.3889 0.007 0.003 0.000 0.009 1.4444 0.007 0.004 0.000 0.009 1.5000 0.007 0.004 0.000 0.009 1.5556 0.007 0.004 0.000 0.009 1.6111 0.007 0.004 0.000 0.009 1.6667 0.007 0.004 0.000 0.009 1.7222 0.007 0.004 0.000 0.009 1.7778 0.007 0.005 0.000 0.009 1.8333 0.007 0.005 0.000 0.009 1.8889 0.007 0.005 0.000 0.009 1.9444 0.007 0.005 0.000 0.009 2.0000 0.007 0.005 0.000 0.009 2.0556 0.007 0.005 0.000 0.009 2.1111 0.007 0.005 0.000 0.009 2.1667 0.007 0.006 0.000 0.009 2.2222 0.007 0.006 0.000 0.009 2.2778 0.007 0.006 0.000 0.009 2.3333 0.007 0.006 0.000 0.009 2.3889 0.007 0.006 0.000 0.009 2.4444 0.007 0.006 0.000 0.009 2.5000 0.007 0.007 0.000 0.009 2.5556 0.007 0.007 0.000 0.009 2.6111 0.007 0.007 0.000 0.009 2.6667 0.007 0.007 0.000 0.009 2.7222 0.007 0.007 0.000 0.009 2.7778 0.007 0.007 0.000 0.009 2.8333 0.007 0.007 0.000 0.009 2.8889 0.007 0.008 0.000 0.009 2.9444 0.007 0.008 0.000 0.009 3.0000 0.007 0.008 0.000 0.009 3.0556 0.007 0.008 0.000 0.009 3.1111 0.007 0.008 0.000 0.009 3.1667 0.007 0.008 0.000 0.009 3.2222 0.007 0.009 0.000 0.009 3.2778 0.007 0.009 0.000 0.009 3.3333 0.007 0.009 0.000 0.009 3.3889 0.007 0.009 0.000 0.009 3.4444 0.007 0.009 0.000 0.009 3.5000 0.007 0.009 0.000 0.009 3.5556 0.007 0.009 0.000 0.009 3.6111 0.007 0.010 0.000 0.009 3.6667 0.007 0.010 0.000 0.009 3.7222 0.007 0.010 0.000 0.009 3.7778 0.007 0.010 0.000 0.009 3.8333 0.007 0.010 0.000 0.009 3.8889 0.007 0.010 0.000 0.009 3.9444 0.007 0.011 0.000 0.009 4.0000 0.007 0.011 0.000 0.009 4.0556 0.007 0.011 0.092 0.009 4.1111 0.007 0.011 0.255 0.009 4.1667 0.007 0.012 0.441 0.009 4.2222 0.007 0.012 0.610 0.009 4.2778 0.007 0.013 0.730 0.009 4.3333 0.007 0.013 0.799 0.009 4.3889 0.007 0.013 0.873 0.009 4.4444 0.007 0.014 0.933 0.009 4.5000 0.007 0.014 0.989 0.009 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 9 4.5556 0.007 0.015 1.043 0.009 4.6111 0.007 0.015 1.094 0.009 4.6667 0.007 0.015 1.143 0.009 4.7222 0.007 0.016 1.189 0.009 4.7778 0.007 0.016 1.234 0.009 4.8333 0.007 0.017 1.277 0.009 4.8889 0.007 0.017 1.319 0.009 4.9444 0.007 0.017 1.360 0.009 5.0000 0.007 0.018 1.399 0.009 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 10 Channel 1 Bottom Length: 10.00 ft. Bottom Width: 5.00 ft. Manning's n: 0.03 Channel bottom slope 1: 0.02 To 1 Channel Left side slope 0: 3 To 1 Channel right side slope 2: 3 To 1 Discharge Structure Riser Height: 0 ft. Riser Diameter: 0 in. Element Flows To: Outlet 1 Outlet 2 Channel Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.001148 0.000000 0.000 0.000 0.0111 0.001163 0.000013 0.019 0.000 0.0222 0.001179 0.000026 0.061 0.000 0.0333 0.001194 0.000039 0.121 0.000 0.0444 0.001209 0.000052 0.197 0.000 0.0556 0.001225 0.000066 0.286 0.000 0.0667 0.001240 0.000080 0.389 0.000 0.0778 0.001255 0.000093 0.504 0.000 0.0889 0.001271 0.000107 0.631 0.000 0.1000 0.001286 0.000122 0.770 0.000 0.1111 0.001301 0.000136 0.920 0.000 0.1222 0.001317 0.000151 1.080 0.000 0.1333 0.001332 0.000165 1.252 0.000 0.1444 0.001348 0.000180 1.434 0.000 0.1556 0.001363 0.000195 1.626 0.000 0.1667 0.001378 0.000211 1.829 0.000 0.1778 0.001394 0.000226 2.041 0.000 0.1889 0.001409 0.000241 2.264 0.000 0.2000 0.001424 0.000257 2.496 0.000 0.2111 0.001440 0.000273 2.738 0.000 0.2222 0.001455 0.000289 2.990 0.000 0.2333 0.001471 0.000305 3.251 0.000 0.2444 0.001486 0.000322 3.523 0.000 0.2556 0.001501 0.000338 3.803 0.000 0.2667 0.001517 0.000355 4.093 0.000 0.2778 0.001532 0.000372 4.393 0.000 0.2889 0.001548 0.000389 4.702 0.000 0.3000 0.001563 0.000407 5.020 0.000 0.3111 0.001578 0.000424 5.348 0.000 0.3222 0.001594 0.000442 5.685 0.000 0.3333 0.001609 0.000459 6.031 0.000 0.3444 0.001625 0.000477 6.387 0.000 0.3556 0.001640 0.000496 6.753 0.000 0.3667 0.001655 0.000514 7.127 0.000 0.3778 0.001671 0.000532 7.511 0.000 0.3889 0.001686 0.000551 7.904 0.000 0.4000 0.001702 0.000570 8.307 0.000 0.4111 0.001717 0.000589 8.719 0.000 0.4222 0.001732 0.000608 9.141 0.000 0.4333 0.001748 0.000627 9.571 0.000 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 11 0.4444 0.001763 0.000647 10.01 0.000 0.4556 0.001779 0.000666 10.46 0.000 0.4667 0.001794 0.000686 10.92 0.000 0.4778 0.001809 0.000706 11.38 0.000 0.4889 0.001825 0.000727 11.86 0.000 0.5000 0.001840 0.000747 12.35 0.000 0.5111 0.001856 0.000767 12.85 0.000 0.5222 0.001871 0.000788 13.35 0.000 0.5333 0.001886 0.000809 13.87 0.000 0.5444 0.001902 0.000830 14.40 0.000 0.5556 0.001917 0.000851 14.93 0.000 0.5667 0.001933 0.000873 15.48 0.000 0.5778 0.001948 0.000894 16.03 0.000 0.5889 0.001964 0.000916 16.60 0.000 0.6000 0.001979 0.000938 17.17 0.000 0.6111 0.001994 0.000960 17.75 0.000 0.6222 0.002010 0.000982 18.35 0.000 0.6333 0.002025 0.001005 18.95 0.000 0.6444 0.002041 0.001027 19.56 0.000 0.6556 0.002056 0.001050 20.19 0.000 0.6667 0.002072 0.001073 20.82 0.000 0.6778 0.002087 0.001096 21.46 0.000 0.6889 0.002103 0.001119 22.11 0.000 0.7000 0.002118 0.001143 22.78 0.000 0.7111 0.002133 0.001166 23.45 0.000 0.7222 0.002149 0.001190 24.13 0.000 0.7333 0.002164 0.001214 24.83 0.000 0.7444 0.002180 0.001238 25.53 0.000 0.7556 0.002195 0.001263 26.24 0.000 0.7667 0.002211 0.001287 26.96 0.000 0.7778 0.002226 0.001312 27.70 0.000 0.7889 0.002242 0.001336 28.44 0.000 0.8000 0.002257 0.001361 29.20 0.000 0.8111 0.002272 0.001387 29.96 0.000 0.8222 0.002288 0.001412 30.74 0.000 0.8333 0.002303 0.001437 31.52 0.000 0.8444 0.002319 0.001463 32.32 0.000 0.8556 0.002334 0.001489 33.12 0.000 0.8667 0.002350 0.001515 33.94 0.000 0.8778 0.002365 0.001541 34.77 0.000 0.8889 0.002381 0.001568 35.60 0.000 0.9000 0.002396 0.001594 36.45 0.000 0.9111 0.002412 0.001621 37.31 0.000 0.9222 0.002427 0.001648 38.18 0.000 0.9333 0.002443 0.001675 39.06 0.000 0.9444 0.002458 0.001702 39.95 0.000 0.9556 0.002473 0.001729 40.85 0.000 0.9667 0.002489 0.001757 41.76 0.000 0.9778 0.002504 0.001785 42.69 0.000 0.9889 0.002520 0.001813 43.62 0.000 1.0000 0.002535 0.001841 44.57 0.000 1.0111 0.002551 0.001869 45.52 0.000 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 12 Gravel Trench Bed 2 Bottom Length: 36.00 ft. Bottom Width: 6.00 ft. Trench bottom slope 1: 0 To 1 Trench Left side slope 0: 0 To 1 Trench right side slope 2: 0 To 1 Material thickness of first layer: 4 Pour Space of material for first layer: 0.4 Material thickness of second layer: 0 Pour Space of material for second layer: 0 Material thickness of third layer: 0 Pour Space of material for third layer: 0 Infiltration On Infiltration rate: 1.3 Infiltration safety factor: 1 Total Volume Infiltrated (ac-ft.): 8.224 Total Volume Through Riser (ac-ft.): 0 Total Volume Through Facility (ac-ft.): 8.224 Percent Infiltrated: 100 Total Precip Applied to Facility: 0 Total Evap From Facility: 0 Discharge Structure Riser Height: 4 ft. Riser Diameter: 8 in. Element Flows To: Outlet 1 Outlet 2 Channel 1 Gravel Trench Bed Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.005 0.000 0.000 0.000 0.0556 0.005 0.000 0.000 0.006 0.1111 0.005 0.000 0.000 0.006 0.1667 0.005 0.000 0.000 0.006 0.2222 0.005 0.000 0.000 0.006 0.2778 0.005 0.000 0.000 0.006 0.3333 0.005 0.000 0.000 0.006 0.3889 0.005 0.000 0.000 0.006 0.4444 0.005 0.000 0.000 0.006 0.5000 0.005 0.001 0.000 0.006 0.5556 0.005 0.001 0.000 0.006 0.6111 0.005 0.001 0.000 0.006 0.6667 0.005 0.001 0.000 0.006 0.7222 0.005 0.001 0.000 0.006 0.7778 0.005 0.001 0.000 0.006 0.8333 0.005 0.001 0.000 0.006 0.8889 0.005 0.001 0.000 0.006 0.9444 0.005 0.001 0.000 0.006 1.0000 0.005 0.002 0.000 0.006 1.0556 0.005 0.002 0.000 0.006 1.1111 0.005 0.002 0.000 0.006 1.1667 0.005 0.002 0.000 0.006 1.2222 0.005 0.002 0.000 0.006 1.2778 0.005 0.002 0.000 0.006 1.3333 0.005 0.002 0.000 0.006 1.3889 0.005 0.002 0.000 0.006 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 13 1.4444 0.005 0.002 0.000 0.006 1.5000 0.005 0.003 0.000 0.006 1.5556 0.005 0.003 0.000 0.006 1.6111 0.005 0.003 0.000 0.006 1.6667 0.005 0.003 0.000 0.006 1.7222 0.005 0.003 0.000 0.006 1.7778 0.005 0.003 0.000 0.006 1.8333 0.005 0.003 0.000 0.006 1.8889 0.005 0.003 0.000 0.006 1.9444 0.005 0.003 0.000 0.006 2.0000 0.005 0.004 0.000 0.006 2.0556 0.005 0.004 0.000 0.006 2.1111 0.005 0.004 0.000 0.006 2.1667 0.005 0.004 0.000 0.006 2.2222 0.005 0.004 0.000 0.006 2.2778 0.005 0.004 0.000 0.006 2.3333 0.005 0.004 0.000 0.006 2.3889 0.005 0.004 0.000 0.006 2.4444 0.005 0.004 0.000 0.006 2.5000 0.005 0.005 0.000 0.006 2.5556 0.005 0.005 0.000 0.006 2.6111 0.005 0.005 0.000 0.006 2.6667 0.005 0.005 0.000 0.006 2.7222 0.005 0.005 0.000 0.006 2.7778 0.005 0.005 0.000 0.006 2.8333 0.005 0.005 0.000 0.006 2.8889 0.005 0.005 0.000 0.006 2.9444 0.005 0.005 0.000 0.006 3.0000 0.005 0.006 0.000 0.006 3.0556 0.005 0.006 0.000 0.006 3.1111 0.005 0.006 0.000 0.006 3.1667 0.005 0.006 0.000 0.006 3.2222 0.005 0.006 0.000 0.006 3.2778 0.005 0.006 0.000 0.006 3.3333 0.005 0.006 0.000 0.006 3.3889 0.005 0.006 0.000 0.006 3.4444 0.005 0.006 0.000 0.006 3.5000 0.005 0.006 0.000 0.006 3.5556 0.005 0.007 0.000 0.006 3.6111 0.005 0.007 0.000 0.006 3.6667 0.005 0.007 0.000 0.006 3.7222 0.005 0.007 0.000 0.006 3.7778 0.005 0.007 0.000 0.006 3.8333 0.005 0.007 0.000 0.006 3.8889 0.005 0.007 0.000 0.006 3.9444 0.005 0.007 0.000 0.006 4.0000 0.005 0.007 0.000 0.006 4.0556 0.005 0.008 0.092 0.006 4.1111 0.005 0.008 0.255 0.006 4.1667 0.005 0.008 0.441 0.006 4.2222 0.005 0.009 0.610 0.006 4.2778 0.005 0.009 0.730 0.006 4.3333 0.005 0.009 0.799 0.006 4.3889 0.005 0.009 0.873 0.006 4.4444 0.005 0.010 0.933 0.006 4.5000 0.005 0.010 0.989 0.006 4.5556 0.005 0.010 1.043 0.006 4.6111 0.005 0.011 1.094 0.006 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 14 4.6667 0.005 0.011 1.143 0.006 4.7222 0.005 0.011 1.189 0.006 4.7778 0.005 0.011 1.234 0.006 4.8333 0.005 0.012 1.277 0.006 4.8889 0.005 0.012 1.319 0.006 4.9444 0.005 0.012 1.360 0.006 5.0000 0.005 0.012 1.399 0.006 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 15 Gravel Trench Bed 3 Bottom Length: 28.00 ft. Bottom Width: 6.00 ft. Trench bottom slope 1: 0 To 1 Trench Left side slope 0: 0 To 1 Trench right side slope 2: 0 To 1 Material thickness of first layer: 4 Pour Space of material for first layer: 0.4 Material thickness of second layer: 0 Pour Space of material for second layer: 0 Material thickness of third layer: 0 Pour Space of material for third layer: 0 Infiltration On Infiltration rate: 1.3 Infiltration safety factor: 1 Total Volume Infiltrated (ac-ft.): 6.456 Total Volume Through Riser (ac-ft.): 0 Total Volume Through Facility (ac-ft.): 6.456 Percent Infiltrated: 100 Total Precip Applied to Facility: 0 Total Evap From Facility: 0 Discharge Structure Riser Height: 4 ft. Riser Diameter: 8 in. Element Flows To: Outlet 1 Outlet 2 Channel 1 Gravel Trench Bed Hydraulic Table Stage(feet) Area(ac.) Volulme(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.003 0.000 0.000 0.000 0.0556 0.003 0.000 0.000 0.005 0.1111 0.003 0.000 0.000 0.005 0.1667 0.003 0.000 0.000 0.005 0.2222 0.003 0.000 0.000 0.005 0.2778 0.003 0.000 0.000 0.005 0.3333 0.003 0.000 0.000 0.005 0.3889 0.003 0.000 0.000 0.005 0.4444 0.003 0.000 0.000 0.005 0.5000 0.003 0.000 0.000 0.005 0.5556 0.003 0.000 0.000 0.005 0.6111 0.003 0.000 0.000 0.005 0.6667 0.003 0.001 0.000 0.005 0.7222 0.003 0.001 0.000 0.005 0.7778 0.003 0.001 0.000 0.005 0.8333 0.003 0.001 0.000 0.005 0.8889 0.003 0.001 0.000 0.005 0.9444 0.003 0.001 0.000 0.005 1.0000 0.003 0.001 0.000 0.005 1.0556 0.003 0.001 0.000 0.005 1.1111 0.003 0.001 0.000 0.005 1.1667 0.003 0.001 0.000 0.005 1.2222 0.003 0.001 0.000 0.005 1.2778 0.003 0.002 0.000 0.005 1.3333 0.003 0.002 0.000 0.005 1.3889 0.003 0.002 0.000 0.005 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 16 1.4444 0.003 0.002 0.000 0.005 1.5000 0.003 0.002 0.000 0.005 1.5556 0.003 0.002 0.000 0.005 1.6111 0.003 0.002 0.000 0.005 1.6667 0.003 0.002 0.000 0.005 1.7222 0.003 0.002 0.000 0.005 1.7778 0.003 0.002 0.000 0.005 1.8333 0.003 0.002 0.000 0.005 1.8889 0.003 0.002 0.000 0.005 1.9444 0.003 0.003 0.000 0.005 2.0000 0.003 0.003 0.000 0.005 2.0556 0.003 0.003 0.000 0.005 2.1111 0.003 0.003 0.000 0.005 2.1667 0.003 0.003 0.000 0.005 2.2222 0.003 0.003 0.000 0.005 2.2778 0.003 0.003 0.000 0.005 2.3333 0.003 0.003 0.000 0.005 2.3889 0.003 0.003 0.000 0.005 2.4444 0.003 0.003 0.000 0.005 2.5000 0.003 0.003 0.000 0.005 2.5556 0.003 0.003 0.000 0.005 2.6111 0.003 0.004 0.000 0.005 2.6667 0.003 0.004 0.000 0.005 2.7222 0.003 0.004 0.000 0.005 2.7778 0.003 0.004 0.000 0.005 2.8333 0.003 0.004 0.000 0.005 2.8889 0.003 0.004 0.000 0.005 2.9444 0.003 0.004 0.000 0.005 3.0000 0.003 0.004 0.000 0.005 3.0556 0.003 0.004 0.000 0.005 3.1111 0.003 0.004 0.000 0.005 3.1667 0.003 0.004 0.000 0.005 3.2222 0.003 0.005 0.000 0.005 3.2778 0.003 0.005 0.000 0.005 3.3333 0.003 0.005 0.000 0.005 3.3889 0.003 0.005 0.000 0.005 3.4444 0.003 0.005 0.000 0.005 3.5000 0.003 0.005 0.000 0.005 3.5556 0.003 0.005 0.000 0.005 3.6111 0.003 0.005 0.000 0.005 3.6667 0.003 0.005 0.000 0.005 3.7222 0.003 0.005 0.000 0.005 3.7778 0.003 0.005 0.000 0.005 3.8333 0.003 0.005 0.000 0.005 3.8889 0.003 0.006 0.000 0.005 3.9444 0.003 0.006 0.000 0.005 4.0000 0.003 0.006 0.000 0.005 4.0556 0.003 0.006 0.092 0.005 4.1111 0.003 0.006 0.255 0.005 4.1667 0.003 0.006 0.441 0.005 4.2222 0.003 0.007 0.610 0.005 4.2778 0.003 0.007 0.730 0.005 4.3333 0.003 0.007 0.799 0.005 4.3889 0.003 0.007 0.873 0.005 4.4444 0.003 0.007 0.933 0.005 4.5000 0.003 0.008 0.989 0.005 4.5556 0.003 0.008 1.043 0.005 4.6111 0.003 0.008 1.094 0.005 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 17 4.6667 0.003 0.008 1.143 0.005 4.7222 0.003 0.009 1.189 0.005 4.7778 0.003 0.009 1.234 0.005 4.8333 0.003 0.009 1.277 0.005 4.8889 0.003 0.009 1.319 0.005 4.9444 0.003 0.009 1.360 0.005 5.0000 0.003 0.010 1.399 0.005 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 18 Analysis Results POC 1 Percent Time Exce edirig + Predeveloped Predeveloped Landuse Totals for POC #1 Total Pervious Area: 0.3 Total Impervious Area: 0 Mitigated Landuse Totals for POC #1 Total Pervious Area: 0.12 Total Impervious Area: 0.185 w,Wma,� N,vUbUy uDo 9. 1 L b 19 N A eC M W W NS Ai W W..] x Mitigated Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.00592 5 year 0.008929 10 year 0.010916 25 year 0.013383 50 year 0.015182 100 year 0.016943 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0 5 year 0 10 year 0 25 year 0 50 year 0 100 year 0 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.002 0.000 1950 0.008 0.000 1951 0.005 0.000 1952 0.005 0.000 1953 0.004 0.000 1954 0.011 0.000 1955 0.010 0.000 1956 0.008 0.000 1957 0.009 0.000 1958 0.007 0.000 site inf only - SPLIT 7/21/2022 11:57:26 AM Page 19 1959 0.007 0.000 1960 0.006 0.000 1961 0.006 0.000 1962 0.005 0.000 1963 0.006 0.000 1964 0.006 0.000 1965 0.005 0.000 1966 0.003 0.000 1967 0.008 0.000 1968 0.009 0.000 1969 0.004 0.000 1970 0.004 0.000 1971 0.007 0.000 1972 0.007 0.000 1973 0.004 0.000 1974 0.007 0.000 1975 0.004 0.000 1976 0.005 0.000 1977 0.003 0.000 1978 0.005 0.000 1979 0.008 0.000 1980 0.006 0.000 1981 0.005 0.000 1982 0.006 0.000 1983 0.007 0.000 1984 0.005 0.000 1985 0.008 0.000 1986 0.020 0.000 1987 0.007 0.000 1988 0.005 0.000 1989 0.004 0.000 1990 0.006 0.000 1991 0.006 0.000 1992 0.005 0.000 1993 0.003 0.000 1994 0.003 0.000 1995 0.006 0.000 1996 0.013 0.000 1997 0.022 0.000 1998 0.003 0.000 1999 0.005 0.000 2000 0.004 0.000 2001 0.001 0.000 2002 0.005 0.000 2003 0.004 0.000 2004 0.005 0.000 2005 0.005 0.000 2006 0.012 0.000 2007 0.010 0.000 2008 0.015 0.000 2009 0.005 0.000 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0216 0.0000 2 0.0201 0.0000 3 0.0148 0.0000 site inf only - SPLIT 7/21/2022 11:57:59 AM Page 20 4 0.0130 0.0000 5 0.0123 0.0000 6 0.0110 0.0000 7 0.0098 0.0000 8 0.0096 0.0000 9 0.0093 0.0000 10 0.0091 0.0000 11 0.0085 0.0000 12 0.0081 0.0000 13 0.0080 0.0000 14 0.0079 0.0000 15 0.0078 0.0000 16 0.0071 0.0000 17 0.0070 0.0000 18 0.0069 0.0000 19 0.0069 0.0000 20 0.0068 0.0000 21 0.0068 0.0000 22 0.0065 0.0000 23 0.0065 0.0000 24 0.0064 0.0000 25 0.0063 0.0000 26 0.0062 0.0000 27 0.0061 0.0000 28 0.0060 0.0000 29 0.0057 0.0000 30 0.0057 0.0000 31 0.0056 0.0000 32 0.0054 0.0000 33 0.0054 0.0000 34 0.0053 0.0000 35 0.0052 0.0000 36 0.0052 0.0000 37 0.0051 0.0000 38 0.0050 0.0000 39 0.0049 0.0000 40 0.0049 0.0000 41 0.0048 0.0000 42 0.0048 0.0000 43 0.0048 0.0000 44 0.0046 0.0000 45 0.0046 0.0000 46 0.0045 0.0000 47 0.0044 0.0000 48 0.0043 0.0000 49 0.0043 0.0000 50 0.0042 0.0000 51 0.0041 0.0000 52 0.0041 0.0000 53 0.0037 0.0000 54 0.0036 0.0000 55 0.0035 0.0000 56 0.0034 0.0000 57 0.0031 0.0000 58 0.0028 0.0000 59 0.0025 0.0000 60 0.0025 0.0000 61 0.0008 0.0000 site inf only - SPLIT 7/21/2022 11:58:00 AM Page 21 site inf only - SPLIT 7/21/2022 11:58:00 AM Page 22 Duration Flows The Facility PASSED Flow(cfs) Predev Mit Percentage Pass/Fail 0.0030 13868 0 0 Pass 0.0031 12684 0 0 Pass 0.0032 11584 0 0 Pass 0.0033 10581 0 0 Pass 0.0035 9616 0 0 Pass 0.0036 8782 0 0 Pass 0.0037 8027 0 0 Pass 0.0038 7349 0 0 Pass 0.0039 6729 0 0 Pass 0.0041 6166 0 0 Pass 0.0042 5662 0 0 Pass 0.0043 5187 0 0 Pass 0.0044 4759 0 0 Pass 0.0046 4361 0 0 Pass 0.0047 3987 0 0 Pass 0.0048 3638 0 0 Pass 0.0049 3311 0 0 Pass 0.0051 3048 0 0 Pass 0.0052 2815 0 0 Pass 0.0053 2629 0 0 Pass 0.0054 2408 0 0 Pass 0.0056 2224 0 0 Pass 0.0057 2079 0 0 Pass 0.0058 1942 0 0 Pass 0.0059 1825 0 0 Pass 0.0060 1705 0 0 Pass 0.0062 1581 0 0 Pass 0.0063 1478 0 0 Pass 0.0064 1372 0 0 Pass 0.0065 1268 0 0 Pass 0.0067 1191 0 0 Pass 0.0068 1111 0 0 Pass 0.0069 1038 0 0 Pass 0.0070 985 0 0 Pass 0.0072 944 0 0 Pass 0.0073 901 0 0 Pass 0.0074 860 0 0 Pass 0.0075 816 0 0 Pass 0.0077 773 0 0 Pass 0.0078 741 0 0 Pass 0.0079 695 0 0 Pass 0.0080 662 0 0 Pass 0.0081 631 0 0 Pass 0.0083 608 0 0 Pass 0.0084 581 0 0 Pass 0.0085 560 0 0 Pass 0.0086 543 0 0 Pass 0.0088 525 0 0 Pass 0.0089 511 0 0 Pass 0.0090 496 0 0 Pass 0.0091 481 0 0 Pass 0.0093 464 0 0 Pass 0.0094 455 0 0 Pass site inf only - SPLIT 7/21/2022 11:58:00 AM Page 23 0.0095 443 0 0 Pass 0.0096 430 0 0 Pass 0.0098 420 0 0 Pass 0.0099 412 0 0 Pass 0.0100 402 0 0 Pass 0.0101 395 0 0 Pass 0.0102 387 0 0 Pass 0.0104 380 0 0 Pass 0.0105 371 0 0 Pass 0.0106 365 0 0 Pass 0.0107 350 0 0 Pass 0.0109 338 0 0 Pass 0.0110 326 0 0 Pass 0.0111 317 0 0 Pass 0.0112 305 0 0 Pass 0.0114 295 0 0 Pass 0.0115 289 0 0 Pass 0.0116 275 0 0 Pass 0.0117 270 0 0 Pass 0.0118 262 0 0 Pass 0.0120 249 0 0 Pass 0.0121 244 0 0 Pass 0.0122 237 0 0 Pass 0.0123 232 0 0 Pass 0.0125 224 0 0 Pass 0.0126 220 0 0 Pass 0.0127 217 0 0 Pass 0.0128 211 0 0 Pass 0.0130 209 0 0 Pass 0.0131 204 0 0 Pass 0.0132 202 0 0 Pass 0.0133 196 0 0 Pass 0.0135 194 0 0 Pass 0.0136 187 0 0 Pass 0.0137 183 0 0 Pass 0.0138 177 0 0 Pass 0.0139 173 0 0 Pass 0.0141 169 0 0 Pass 0.0142 167 0 0 Pass 0.0143 163 0 0 Pass 0.0144 155 0 0 Pass 0.0146 153 0 0 Pass 0.0147 146 0 0 Pass 0.0148 139 0 0 Pass 0.0149 136 0 0 Pass 0.0151 132 0 0 Pass 0.0152 131 0 0 Pass site inf only - SPLIT 7/21/2022 11:58:00 AM Page 24 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0 acre-feet On-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. Off-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. site inf only - SPLIT 7/21/2022 11:58:00 AM Page 25 LID Report LID Technique Usedfor Total Volume Volume Infiltration Cumulative Percent Water duality Percent Comment Treatment 7 Needs Through Volume Volume Volume Water Quality Treatment Facility (ac-ft) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit Channel 1 POC ❑ 0.00 ❑ 0.00 Gravel Trench Bed 1 ❑ 11.59 ❑ 100.00 Gravel Trench Bed 2 ❑ 7.48 ❑ 100.00 Gravel Trench Bed ❑ 5.37 ❑ 100.00 Total Volume Infiltrated 24.95 0.00 0.00 100.00 0.00 0% No Treat. Credit Duration Compliance with LID Analysis Standard B% of2-yrto 50% of Result = 2 yr Passed site inf only - SPLIT 7/21/2022 11:58:00 AM Page 26 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. site inf only - SPLIT 7/21/2022 11:58:18 AM Page 27 Appendix Predeveloped Schematic �.� Ba: Wi 1 0.3, site inf only - SPLIT 7/21/2022 11:58:18 AM Page 28 Mitigated Schematic LOW E �� Lot A R 0.18a ,.. 1.3 SI Gravel Gravel Trench Tren& S S Channel ❑t B - Roof ndscaping site inf only - SPLIT 7/21/2022 11:58:20 AM Page 29 Predeveloped UCI File site inf only - SPLIT 7/21/2022 11:58:21 AM Page 30 Mitigated UC/ File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 END GLOBAL 2009 09 30 UNIT SYSTEM FILES <File> <Un#> OPN SEQUENCE 1 <----------- File Name-------- ---------------------->*** *** INGRP INDELT 00:15 PERLND 17 IMPLND 6 IMPLND 4 RCHRES 1 RCHRES 2 RCHRES 3 RCHRES 4 COPY 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INF01 # - #<---------- Title ----------- >***TRAN PIVL DIG1 FIL1 1 Channel 1 MAX END DISPLY-INF01 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO PYR DIG2 FIL2 YRND 1 2 30 9 <PLS ><------- Name ------- >NBLKS Unit -systems Printer *** # - # User t-series Engl Metr *** in out *** 17 C, Lawn, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 17 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY site inf only -SPLIT 7/21/2022 11:58:21 AM Page 31 PRINT -INFO <PLS > ***************** Print -flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT -INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 17 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 17 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATEI <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS 17 0 0 0 0 2.5 1 END PWAT-STATEI END PERLND IMPLND GEN-INFO <PLS ><------- Name ------- > 6 DRIVEWAYS/MOD 4 ROOF TOPS/FLAT END GEN-INFO *** Section IWATER*** Unit -systems Printer *** User t-series Engl Metr *** in out *** 1 1 1 27 0 1 1 1 27 0 ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 6 0 0 1 0 0 0 4 0 0 1 0 0 0 END ACTIVITY PRINT -INFO <ILS > ******** Print -flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 6 0 0 4 0 0 0 1 9 4 0 0 4 0 0 0 1 9 END PRINT -INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 6 0 0 0 0 0 4 0 0 0 0 0 END IWAT-PARM1 GWVS 0 site inf only - SPLIT 7/21/2022 11:58:21 AM Page 32 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 6 400 0.05 0.1 0.08 4 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 6 0 0 4 0 0 END IWAT-PARM3 IWAT-STATEI <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 6 0 0 4 0 0 END IWAT-STATEI END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** LOWER*** PERLND 17 0.12 RCHRES 1 2 PERLND 17 0.12 RCHRES 1 3 IMPLND 6 0.06 RCHRES 1 5 Lot B - Roof and Landscaping*** IMPLND 4 0.07 RCHRES 2 5 Lot A Roof*** IMPLND 4 0.055 RCHRES 3 5 ******Routing****** RCHRES 1 1 RCHRES 4 7 RCHRES 1 COPY 1 17 RCHRES 2 1 RCHRES 4 7 RCHRES 2 COPY 1 17 RCHRES 3 1 RCHRES 4 7 RCHRES 3 COPY 1 17 RCHRES 4 1 COPY 501 16 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------ >< --- > User T-series Engl Metr LKFG *** in out *** 1 Gravel Trench Be-005 2 1 1 1 28 0 1 2 Gravel Trench Be-008 2 1 1 1 28 0 1 3 Gravel Trench Be-010 2 1 1 1 28 0 1 4 Channel 1 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** site inf only - SPLIT 7/21/2022 11:58:21 AM Page 33 # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 3 1 0 0 0 0 0 0 0 0 0 4 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT -INFO <PLS > ***************** Print -flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 2 4 0 0 0 0 0 0 0 0 0 1 9 3 4 0 0 0 0 0 0 0 0 0 1 9 4 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT -INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC Al A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 5 0 0 0 0 0 0 0 0 2 2 2 2 2 2 0 1 0 0 4 5 0 0 0 0 0 0 0 0 2 2 2 2 2 3 0 1 0 0 4 5 0 0 0 0 0 0 0 0 2 2 2 2 2 4 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------ ><-------- ><-------- ><-------- ><-------- ><-------- ><-------- > *** 1 1 0.01 0.0 0.0 0.5 0.0 2 2 0.01 0.0 0.0 0.5 0.0 3 3 0.01 0.0 0.0 0.5 0.0 4 4 0.01 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><-------- > <--- ><--- ><--- ><--- ><---> *** <--- ><--- ><--- ><--- ><---> 1 0 4.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2 0 4.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 3 0 4.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 4 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC -ACTIONS END SPEC -ACTIONS FTABLES FTABLE 1 92 5 Depth Area Volume Outflowl Outflow2 (ft) (acres) (acre-ft) (cfs) (cfs) 0.000000 0.006979 0.000000 0.000000 0.000000 0.055556 0.006979 0.000155 0.000000 0.009148 0.111111 0.006979 0.000310 0.000000 0.009148 0.166667 0.006979 0.000465 0.000000 0.009148 0.222222 0.006979 0.000620 0.000000 0.009148 0.277778 0.006979 0.000775 0.000000 0.009148 0.333333 0.006979 0.000931 0.000000 0.009148 0.388889 0.006979 0.001086 0.000000 0.009148 0.444444 0.006979 0.001241 0.000000 0.009148 0.500000 0.006979 0.001396 0.000000 0.009148 0.555556 0.006979 0.001551 0.000000 0.009148 0.611111 0.006979 0.001706 0.000000 0.009148 0.666667 0.006979 0.001861 0.000000 0.009148 0.722222 0.006979 0.002016 0.000000 0.009148 0.777778 0.006979 0.002171 0.000000 0.009148 0.833333 0.006979 0.002326 0.000000 0.009148 Velocity Travel Time*** (ft/sec) (Minutes)*** site inf only - SPLIT 7/21/2022 11:58:21 AM Page 34 0.888889 0.006979 0.002481 0.000000 0.009148 0.944444 0.006979 0.002636 0.000000 0.009148 1.000000 0.006979 0.002792 0.000000 0.009148 1.055556 0.006979 0.002947 0.000000 0.009148 1.111111 0.006979 0.003102 0.000000 0.009148 1.166667 0.006979 0.003257 0.000000 0.009148 1.222222 0.006979 0.003412 0.000000 0.009148 1.277778 0.006979 0.003567 0.000000 0.009148 1.333333 0.006979 0.003722 0.000000 0.009148 1.388889 0.006979 0.003877 0.000000 0.009148 1.444444 0.006979 0.004032 0.000000 0.009148 1.500000 0.006979 0.004187 0.000000 0.009148 1.555556 0.006979 0.004342 0.000000 0.009148 1.611111 0.006979 0.004498 0.000000 0.009148 1.666667 0.006979 0.004653 0.000000 0.009148 1.722222 0.006979 0.004808 0.000000 0.009148 1.777778 0.006979 0.004963 0.000000 0.009148 1.833333 0.006979 0.005118 0.000000 0.009148 1.888889 0.006979 0.005273 0.000000 0.009148 1.944444 0.006979 0.005428 0.000000 0.009148 2.000000 0.006979 0.005583 0.000000 0.009148 2.055556 0.006979 0.005738 0.000000 0.009148 2.111111 0.006979 0.005893 0.000000 0.009148 2.166667 0.006979 0.006048 0.000000 0.009148 2.222222 0.006979 0.006203 0.000000 0.009148 2.277778 0.006979 0.006359 0.000000 0.009148 2.333333 0.006979 0.006514 0.000000 0.009148 2.388889 0.006979 0.006669 0.000000 0.009148 2.444444 0.006979 0.006824 0.000000 0.009148 2.500000 0.006979 0.006979 0.000000 0.009148 2.555556 0.006979 0.007134 0.000000 0.009148 2.611111 0.006979 0.007289 0.000000 0.009148 2.666667 0.006979 0.007444 0.000000 0.009148 2.722222 0.006979 0.007599 0.000000 0.009148 2.777778 0.006979 0.007754 0.000000 0.009148 2.833333 0.006979 0.007909 0.000000 0.009148 2.888889 0.006979 0.008064 0.000000 0.009148 2.944444 0.006979 0.008220 0.000000 0.009148 3.000000 0.006979 0.008375 0.000000 0.009148 3.055556 0.006979 0.008530 0.000000 0.009148 3.111111 0.006979 0.008685 0.000000 0.009148 3.166667 0.006979 0.008840 0.000000 0.009148 3.222222 0.006979 0.008995 0.000000 0.009148 3.277778 0.006979 0.009150 0.000000 0.009148 3.333333 0.006979 0.009305 0.000000 0.009148 3.388889 0.006979 0.009460 0.000000 0.009148 3.444444 0.006979 0.009615 0.000000 0.009148 3.500000 0.006979 0.009770 0.000000 0.009148 3.555556 0.006979 0.009926 0.000000 0.009148 3.611111 0.006979 0.010081 0.000000 0.009148 3.666667 0.006979 0.010236 0.000000 0.009148 3.722222 0.006979 0.010391 0.000000 0.009148 3.777778 0.006979 0.010546 0.000000 0.009148 3.833333 0.006979 0.010701 0.000000 0.009148 3.888889 0.006979 0.010856 0.000000 0.009148 3.944444 0.006979 0.011011 0.000000 0.009148 4.000000 0.006979 0.011166 0.000000 0.009148 4.055556 0.006979 0.011554 0.092279 0.009148 4.111111 0.006979 0.011942 0.255267 0.009148 4.166667 0.006979 0.012329 0.441835 0.009148 4.222222 0.006979 0.012717 0.610909 0.009148 4.277778 0.006979 0.013105 0.730523 0.009148 4.333333 0.006979 0.013493 0.799562 0.009148 4.388889 0.006979 0.013880 0.872951 0.009148 4.444444 0.006979 0.014268 0.933224 0.009148 4.500000 0.006979 0.014656 0.989833 0.009148 4.555556 0.006979 0.015043 1.043376 0.009148 4.611111 0.006979 0.015431 1.094302 0.009148 4.666667 0.006979 0.015819 1.142961 0.009148 4.722222 0.006979 0.016207 1.189631 0.009148 site inf only - SPLIT 7/21/2022 11:58:21 AM Page 35 4.777778 0.006979 0.016594 1.234539 4.833333 0.006979 0.016982 1.277869 4.888889 0.006979 0.017370 1.319778 4.944444 0.006979 0.017757 1.360396 5.000000 0.006979 0.018145 1.399836 5.055556 0.006979 0.018533 1.438194 END FTABLE 1 FTABLE 4 91 4 Depth Area Volume Outflowl (ft) (acres) (acre-ft) (cfs) 0.000000 0.001148 0.000000 0.000000 0.011111 0.001163 0.000013 0.019465 0.022222 0.001179 0.000026 0.061909 0.033333 0.001194 0.000039 0.121915 0.044444 0.001209 0.000052 0.197299 0.055556 0.001225 0.000066 0.286748 0.066667 0.001240 0.000080 0.389356 0.077778 0.001255 0.000093 0.504453 0.088889 0.001271 0.000107 0.631522 0.100000 0.001286 0.000122 0.770149 0.111111 0.001301 0.000136 0.919995 0.122222 0.001317 0.000151 1.080779 0.133333 0.001332 0.000165 1.252266 0.144444 0.001348 0.000180 1.434256 0.155556 0.001363 0.000195 1.626577 0.166667 0.001378 0.000211 1.829081 0.177778 0.001394 0.000226 2.041643 0.188889 0.001409 0.000241 2.264151 0.200000 0.001424 0.000257 2.496511 0.211111 0.001440 0.000273 2.738639 0.222222 0.001455 0.000289 2.990464 0.233333 0.001471 0.000305 3.251923 0.244444 0.001486 0.000322 3.522964 0.255556 0.001501 0.000338 3.803539 0.266667 0.001517 0.000355 4.093611 0.277778 0.001532 0.000372 4.393145 0.288889 0.001548 0.000389 4.702114 0.300000 0.001563 0.000407 5.020496 0.311111 0.001578 0.000424 5.348270 0.322222 0.001594 0.000442 5.685424 0.333333 0.001609 0.000459 6.031947 0.344444 0.001625 0.000477 6.387831 0.355556 0.001640 0.000496 6.753072 0.366667 0.001655 0.000514 7.127668 0.377778 0.001671 0.000532 7.511621 0.388889 0.001686 0.000551 7.904935 0.400000 0.001702 0.000570 8.307614 0.411111 0.001717 0.000589 8.719668 0.422222 0.001732 0.000608 9.141105 0.433333 0.001748 0.000627 9.571937 0.444444 0.001763 0.000647 10.01218 0.455556 0.001779 0.000666 10.46184 0.466667 0.001794 0.000686 10.92094 0.477778 0.001809 0.000706 11.38950 0.488889 0.001825 0.000727 11.86753 0.500000 0.001840 0.000747 12.35506 0.511111 0.001856 0.000767 12.85210 0.522222 0.001871 0.000788 13.35867 0.533333 0.001886 0.000809 13.87481 0.544444 0.001902 0.000830 14.40053 0.555556 0.001917 0.000851 14.93586 0.566667 0.001933 0.000873 15.48082 0.577778 0.001948 0.000894 16.03543 0.588889 0.001964 0.000916 16.59974 0.600000 0.001979 0.000938 17.17375 0.611111 0.001994 0.000960 17.75751 0.622222 0.002010 0.000982 18.35103 0.633333 0.002025 0.001005 18.95435 0.644444 0.002041 0.001027 19.56749 0.009148 0.009148 0.009148 0.009148 0.009148 0.009148 Velocity Travel Time*** (ft/sec) (Minutes)*** site inf only - SPLIT 7/21/2022 11:58:21 AM Page 36 0.655556 0.002056 0.001050 20.19050 0.666667 0.002072 0.001073 20.82339 0.677778 0.002087 0.001096 21.46619 0.688889 0.002103 0.001119 22.11895 0.700000 0.002118 0.001143 22.78169 0.711111 0.002133 0.001166 23.45443 0.722222 0.002149 0.001190 24.13723 0.733333 0.002164 0.001214 24.83010 0.744444 0.002180 0.001238 25.53307 0.755556 0.002195 0.001263 26.24620 0.766667 0.002211 0.001287 26.96949 0.777778 0.002226 0.001312 27.70300 0.788889 0.002242 0.001336 28.44675 0.800000 0.002257 0.001361 29.20078 0.811111 0.002272 0.001387 29.96512 0.822222 0.002288 0.001412 30.73981 0.833333 0.002303 0.001437 31.52487 0.844444 0.002319 0.001463 32.32036 0.855556 0.002334 0.001489 33.12629 0.866667 0.002350 0.001515 33.94271 0.877778 0.002365 0.001541 34.76966 0.888889 0.002381 0.001568 35.60716 0.900000 0.002396 0.001594 36.45525 0.911111 0.002412 0.001621 37.31397 0.922222 0.002427 0.001648 38.18335 0.933333 0.002443 0.001675 39.06344 0.944444 0.002458 0.001702 39.95426 0.955556 0.002473 0.001729 40.85585 0.966667 0.002489 0.001757 41.76825 0.977778 0.002504 0.001785 42.69150 0.988889 0.002520 0.001813 43.62563 1.000000 0.002535 0.001841 44.57068 END FTABLE 4 FTABLE 2 92 5 Depth Area Volume Outflowl Outflow2 (ft) (acres) (acre-ft) (cfs) (cfs) 0.000000 0.004959 0.000000 0.000000 0.000000 0.055556 0.004959 0.000110 0.000000 0.006500 0.111111 0.004959 0.000220 0.000000 0.006500 0.166667 0.004959 0.000331 0.000000 0.006500 0.222222 0.004959 0.000441 0.000000 0.006500 0.277778 0.004959 0.000551 0.000000 0.006500 0.333333 0.004959 0.000661 0.000000 0.006500 0.388889 0.004959 0.000771 0.000000 0.006500 0.444444 0.004959 0.000882 0.000000 0.006500 0.500000 0.004959 0.000992 0.000000 0.006500 0.555556 0.004959 0.001102 0.000000 0.006500 0.611111 0.004959 0.001212 0.000000 0.006500 0.666667 0.004959 0.001322 0.000000 0.006500 0.722222 0.004959 0.001433 0.000000 0.006500 0.777778 0.004959 0.001543 0.000000 0.006500 0.833333 0.004959 0.001653 0.000000 0.006500 0.888889 0.004959 0.001763 0.000000 0.006500 0.944444 0.004959 0.001873 0.000000 0.006500 1.000000 0.004959 0.001983 0.000000 0.006500 1.055556 0.004959 0.002094 0.000000 0.006500 1.111111 0.004959 0.002204 0.000000 0.006500 1.166667 0.004959 0.002314 0.000000 0.006500 1.222222 0.004959 0.002424 0.000000 0.006500 1.277778 0.004959 0.002534 0.000000 0.006500 1.333333 0.004959 0.002645 0.000000 0.006500 1.388889 0.004959 0.002755 0.000000 0.006500 1.444444 0.004959 0.002865 0.000000 0.006500 1.500000 0.004959 0.002975 0.000000 0.006500 1.555556 0.004959 0.003085 0.000000 0.006500 1.611111 0.004959 0.003196 0.000000 0.006500 1.666667 0.004959 0.003306 0.000000 0.006500 1.722222 0.004959 0.003416 0.000000 0.006500 1.777778 0.004959 0.003526 0.000000 0.006500 Velocity Travel Time*** (ft/sec) (Minutes)*** site inf only - SPLIT 7/21/2022 11:58:21 AM Page 37 1.833333 0.004959 0.003636 0.000000 0.006500 1.888889 0.004959 0.003747 0.000000 0.006500 1.944444 0.004959 0.003857 0.000000 0.006500 2.000000 0.004959 0.003967 0.000000 0.006500 2.055556 0.004959 0.004077 0.000000 0.006500 2.111111 0.004959 0.004187 0.000000 0.006500 2.166667 0.004959 0.004298 0.000000 0.006500 2.222222 0.004959 0.004408 0.000000 0.006500 2.277778 0.004959 0.004518 0.000000 0.006500 2.333333 0.004959 0.004628 0.000000 0.006500 2.388889 0.004959 0.004738 0.000000 0.006500 2.444444 0.004959 0.004848 0.000000 0.006500 2.500000 0.004959 0.004959 0.000000 0.006500 2.555556 0.004959 0.005069 0.000000 0.006500 2.611111 0.004959 0.005179 0.000000 0.006500 2.666667 0.004959 0.005289 0.000000 0.006500 2.722222 0.004959 0.005399 0.000000 0.006500 2.777778 0.004959 0.005510 0.000000 0.006500 2.833333 0.004959 0.005620 0.000000 0.006500 2.888889 0.004959 0.005730 0.000000 0.006500 2.944444 0.004959 0.005840 0.000000 0.006500 3.000000 0.004959 0.005950 0.000000 0.006500 3.055556 0.004959 0.006061 0.000000 0.006500 3.111111 0.004959 0.006171 0.000000 0.006500 3.166667 0.004959 0.006281 0.000000 0.006500 3.222222 0.004959 0.006391 0.000000 0.006500 3.277778 0.004959 0.006501 0.000000 0.006500 3.333333 0.004959 0.006612 0.000000 0.006500 3.388889 0.004959 0.006722 0.000000 0.006500 3.444444 0.004959 0.006832 0.000000 0.006500 3.500000 0.004959 0.006942 0.000000 0.006500 3.555556 0.004959 0.007052 0.000000 0.006500 3.611111 0.004959 0.007163 0.000000 0.006500 3.666667 0.004959 0.007273 0.000000 0.006500 3.722222 0.004959 0.007383 0.000000 0.006500 3.777778 0.004959 0.007493 0.000000 0.006500 3.833333 0.004959 0.007603 0.000000 0.006500 3.888889 0.004959 0.007713 0.000000 0.006500 3.944444 0.004959 0.007824 0.000000 0.006500 4.000000 0.004959 0.007934 0.000000 0.006500 4.055556 0.004959 0.008209 0.092279 0.006500 4.111111 0.004959 0.008485 0.255267 0.006500 4.166667 0.004959 0.008760 0.441835 0.006500 4.222222 0.004959 0.009036 0.610909 0.006500 4.277778 0.004959 0.009311 0.730523 0.006500 4.333333 0.004959 0.009587 0.799562 0.006500 4.388889 0.004959 0.009862 0.872951 0.006500 4.444444 0.004959 0.010138 0.933224 0.006500 4.500000 0.004959 0.010413 0.989833 0.006500 4.555556 0.004959 0.010689 1.043376 0.006500 4.611111 0.004959 0.010964 1.094302 0.006500 4.666667 0.004959 0.011240 1.142961 0.006500 4.722222 0.004959 0.011515 1.189631 0.006500 4.777778 0.004959 0.011791 1.234539 0.006500 4.833333 0.004959 0.012066 1.277869 0.006500 4.888889 0.004959 0.012342 1.319778 0.006500 4.944444 0.004959 0.012617 1.360396 0.006500 5.000000 0.004959 0.012893 1.399836 0.006500 5.055556 0.004959 0.013168 1.438194 0.006500 END FTABLE 2 FTABLE 3 92 5 Depth Area Volume Outflowl Outflow2 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (cfs) (ft/sec) (Minutes)*** 0.000000 0.003857 0.000000 0.000000 0.000000 0.055556 0.003857 0.000086 0.000000 0.005056 0.111111 0.003857 0.000171 0.000000 0.005056 0.166667 0.003857 0.000257 0.000000 0.005056 0.222222 0.003857 0.000343 0.000000 0.005056 0.277778 0.003857 0.000429 0.000000 0.005056 site inf only - SPLIT 7/21/2022 11:58:21 AM Page 38 0.333333 0.003857 0.000514 0.000000 0.005056 0.388889 0.003857 0.000600 0.000000 0.005056 0.444444 0.003857 0.000686 0.000000 0.005056 0.500000 0.003857 0.000771 0.000000 0.005056 0.555556 0.003857 0.000857 0.000000 0.005056 0.611111 0.003857 0.000943 0.000000 0.005056 0.666667 0.003857 0.001028 0.000000 0.005056 0.722222 0.003857 0.001114 0.000000 0.005056 0.777778 0.003857 0.001200 0.000000 0.005056 0.833333 0.003857 0.001286 0.000000 0.005056 0.888889 0.003857 0.001371 0.000000 0.005056 0.944444 0.003857 0.001457 0.000000 0.005056 1.000000 0.003857 0.001543 0.000000 0.005056 1.055556 0.003857 0.001628 0.000000 0.005056 1.111111 0.003857 0.001714 0.000000 0.005056 1.166667 0.003857 0.001800 0.000000 0.005056 1.222222 0.003857 0.001886 0.000000 0.005056 1.277778 0.003857 0.001971 0.000000 0.005056 1.333333 0.003857 0.002057 0.000000 0.005056 1.388889 0.003857 0.002143 0.000000 0.005056 1.444444 0.003857 0.002228 0.000000 0.005056 1.500000 0.003857 0.002314 0.000000 0.005056 1.555556 0.003857 0.002400 0.000000 0.005056 1.611111 0.003857 0.002485 0.000000 0.005056 1.666667 0.003857 0.002571 0.000000 0.005056 1.722222 0.003857 0.002657 0.000000 0.005056 1.777778 0.003857 0.002743 0.000000 0.005056 1.833333 0.003857 0.002828 0.000000 0.005056 1.888889 0.003857 0.002914 0.000000 0.005056 1.944444 0.003857 0.003000 0.000000 0.005056 2.000000 0.003857 0.003085 0.000000 0.005056 2.055556 0.003857 0.003171 0.000000 0.005056 2.111111 0.003857 0.003257 0.000000 0.005056 2.166667 0.003857 0.003343 0.000000 0.005056 2.222222 0.003857 0.003428 0.000000 0.005056 2.277778 0.003857 0.003514 0.000000 0.005056 2.333333 0.003857 0.003600 0.000000 0.005056 2.388889 0.003857 0.003685 0.000000 0.005056 2.444444 0.003857 0.003771 0.000000 0.005056 2.500000 0.003857 0.003857 0.000000 0.005056 2.555556 0.003857 0.003942 0.000000 0.005056 2.611111 0.003857 0.004028 0.000000 0.005056 2.666667 0.003857 0.004114 0.000000 0.005056 2.722222 0.003857 0.004200 0.000000 0.005056 2.777778 0.003857 0.004285 0.000000 0.005056 2.833333 0.003857 0.004371 0.000000 0.005056 2.888889 0.003857 0.004457 0.000000 0.005056 2.944444 0.003857 0.004542 0.000000 0.005056 3.000000 0.003857 0.004628 0.000000 0.005056 3.055556 0.003857 0.004714 0.000000 0.005056 3.111111 0.003857 0.004800 0.000000 0.005056 3.166667 0.003857 0.004885 0.000000 0.005056 3.222222 0.003857 0.004971 0.000000 0.005056 3.277778 0.003857 0.005057 0.000000 0.005056 3.333333 0.003857 0.005142 0.000000 0.005056 3.388889 0.003857 0.005228 0.000000 0.005056 3.444444 0.003857 0.005314 0.000000 0.005056 3.500000 0.003857 0.005399 0.000000 0.005056 3.555556 0.003857 0.005485 0.000000 0.005056 3.611111 0.003857 0.005571 0.000000 0.005056 3.666667 0.003857 0.005657 0.000000 0.005056 3.722222 0.003857 0.005742 0.000000 0.005056 3.777778 0.003857 0.005828 0.000000 0.005056 3.833333 0.003857 0.005914 0.000000 0.005056 3.888889 0.003857 0.005999 0.000000 0.005056 3.944444 0.003857 0.006085 0.000000 0.005056 4.000000 0.003857 0.006171 0.000000 0.005056 4.055556 0.003857 0.006385 0.092279 0.005056 4.111111 0.003857 0.006599 0.255267 0.005056 4.166667 0.003857 0.006814 0.441835 0.005056 site inf only - SPLIT 7/21/2022 11:58:21 AM Page 39 4.222222 0.003857 0.007028 0.610909 0.005056 4.277778 0.003857 0.007242 0.730523 0.005056 4.333333 0.003857 0.007456 0.799562 0.005056 4.388889 0.003857 0.007671 0.872951 0.005056 4.444444 0.003857 0.007885 0.933224 0.005056 4.500000 0.003857 0.008099 0.989833 0.005056 4.555556 0.003857 0.008313 1.043376 0.005056 4.611111 0.003857 0.008528 1.094302 0.005056 4.666667 0.003857 0.008742 1.142961 0.005056 4.722222 0.003857 0.008956 1.189631 0.005056 4.777778 0.003857 0.009170 1.234539 0.005056 4.833333 0.003857 0.009385 1.277869 0.005056 4.888889 0.003857 0.009599 1.319778 0.005056 4.944444 0.003857 0.009813 1.360396 0.005056 5.000000 0.003857 0.010028 1.399836 0.005056 5.055556 0.003857 0.010242 1.438194 0.005056 END FTABLE 3 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 0.8 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 0.8 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 4 HYDR RO 1 1 1 WDM 1004 FLOW ENGL REPL RCHRES 4 HYDR STAGE 1 1 1 WDM 1005 STAG ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS -LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS -LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS -LINK 2 MASS -LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS -LINK 3 MASS -LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS -LINK 5 MASS -LINK 7 RCHRES OFLOW OVOL 1 RCHRES INFLOW IVOL END MASS -LINK 7 MASS -LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS -LINK 16 MASS -LINK 17 RCHRES OFLOW OVOL 1 COPY INPUT MEAN END MASS -LINK 17 END MASS -LINK END RUN site inf only - SPLIT 7/21/2022 11:58:21 AM Page 40 Predeveloped HSPF Message File site inf only - SPLIT 7/21/2022 11:58:21 AM Page 41 Mitigated HSPF Message File site inf only - SPLIT 7/21/2022 11:58:21 AM Page 42 Disclaimer Legal Notice This program and accompanying documentation are provided 'as -is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by: Clear Creek Solutions, Inc. 2005-2022; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com site inf only - SPLIT 7/21/2022 11:58:21 AM Page 43 No. 5 — Catch Basins Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed General Trash & Trash or debris which is located immediately No Trash or debris located Debris in front of the catch basin opening or is immediately in front of blocking inletting capacity of the basin by catch basin or on grate more than 10%. opening. Trash or debris (in the basin) that exceeds 60 No trash or debris in the percent of the sump depth as measured from catch basin. the bottom of basin to invert of the lowest pipe into or out of the basin, but in no case less than a minimum of six inches clearance from the debris surface to the invert of the lowest pipe. Trash or debris in any inlet or outlet pipe Inlet and outlet pipes free blocking more than 1/3 of its height. of trash or debris. Dead animals or vegetation that could No dead animals or generate odors that could cause complaints vegetation present within or dangerous gases (e.g., methane). the catch basin. Sediment Sediment (in the basin) that exceeds 60 No sediment in the catch percent of the sump depth as measured from basin the bottom of basin to invert of the lowest pipe into or out of the basin, but in no case less than a minimum of 6 inches clearance from the sediment surface to the invert of the lowest pipe. Structure Top slab has holes larger than 2 square Top slab is free of holes Damage to inches or cracks wider than 114 inch and cracks. Frame and/or Top Slab (Intent is to make sure no material is running into basin). Frame not sitting flush on top slab, i.e., Frame is sitting flush on separation of more than 3/4 inch of the frame the riser rings or top slab from the top slab. Frame not securely and firmly attached. attached Fractures or Maintenance person judges that structure is Basin replaced or repaired Cracks in unsound, to design standards. Basin Walls/ Bottom Grout fillet has separated or cracked wider Pipe is regrouted and than 1/2 inch and longer than 1 foot at the secure at basin wall. joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. Settlement/ If failure of basin has created a safety, Basin replaced or repaired Misalignment function, or design problem. to design standards. Vegetation Vegetation growing across and blocking more No vegetation blocking than 10% of the basin opening. opening to basin. Vegetation growing in inlet/outlet pipe joints No vegetation or root that is more than six inches tall and less than growth present. six inches apart. Contamination See "Detention Ponds" (No. 1). No pollution present. and Pollution Volume V— Runoff Treatment BMPs — December 2014 4-38 No. 6 — Catch Basins Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance Is performed Catch Basin Cover Not in Cover is missing or only partially in place. Catch basin cover is Cover Place Any open catch basin requires maintenance. closed Locking Mechanism cannot be opened by one Mechanism opens with Mechanism maintenance person with proper tools. Bolts proper tools. Not Working into frame have less than 1/2 inch of thread. Cover Difficult One maintenance person cannot remove lid Cover can be removed by to Remove after applying normal lifting pressure. one maintenance person. (Intent is keep cover from sealing off access to maintenance.) Ladder Ladder Rungs Ladder is unsafe due to missing rungs, not Ladder meets design Unsafe securely attached to basin wall, standards and allows misalignment, rust, cracks, or sharp edges. maintenance person safe access. Metal Grates Grate opening Grate with opening wider than 7/8 inch. Grate opening meets (If Applicable) Unsafe design standards. Trash and Trash and debris that is blocking more than Grate free of trash and Debris 20% of grate surface inletting capacity. debris. Damaged or Grate missing or broken member(s) of the Grate is in place and Missing. grate. meets design standards. No. 6 — Debris Barriers (e.g., Trash Racks) Maintenance Defect Condition When Maintenance is Results Expected When Components Needed Maintenance is Performed General Trash and Trash or debris that is plugging more Barrier cleared to design flow Debris than 20% of the openings in the barrier. capacity. Metal Damaged/ Bars are bent out of shape more than 3 Bars in place with no bends more Missing inches. than 3/4 inch. Bars. Bars are missing or entire barrier Bars in place according to design. missing. Bars are loose and rust is causing 50% Barrier replaced or repaired to deterioration to any part of barrier. design standards. let/Outlet F Debris barrier missing or not attached to Barrier firmly attached to pipe ipe pipe Volume V — Runoff Treatment BMPs — December 2014 4-39 .0 April 6, 2022 Project No. 20190101EO02 Vector One, LLC 8415 192" d Street SW Edmonds, Washington 98026 a s s o c i a t e d earth sciences i n c o r p o r a t e d Attention: Mr. Carl Clapp Subject: Limited Subsurface Exploration and Infiltration Feasibility Assessment 8354 and 8344 Olympic View Drive Snohomish County Tax Parcels 27041800109-200 and -300 Edmonds, Washington Dear Mr. Clapp: Associated Earth Sciences, Inc. (AESI) is pleased to present our findings and stormwater infiltration feasibility assessment and recommendations for the above -referenced project. Our general understanding of the project is based on discussions with you, our previous work at the subject site, our experience working in the project vicinity, and review of conceptual project documents. Based on the results of our subsurface explorations, we consider infiltration to be feasible for this project based on the presence of permeable Vashon advance outwash sands at a depth of about 5 feet beneath surficial fill and weathered soil horizon, as discussed in this letter -report. This letter -report supplements our previous reports for the project site, titled "Geotechnical Report Update and Geotechnical Plan Review" dated March 19, 2019 and "Soldier Pile Shoring Wall Design Recommendations" dated July 15, 2019, and provides infiltration recommendations. This letter -report has been prepared for the exclusive use of Vector One, LLC, for specific application to this project. Within the limitations of scope and schedule, our services have been performed in accordance with generally accepted local hydrogeologic and geotechnical engineering practices in effect at the time our letter -report was prepared. No other warranty, express or implied, is made. Our work was performed in general accordance with our proposal, dated March 1, 2022. SITE AND PROJECT DESCRIPTION The subject site consists of two adjoining parcels totaling 0.65 acres located at 8354 and 8344 Olympic View Drive in Edmonds, Washington (Snohomish County Parcel Nos. 27041800109-200 and 27041800109-300). The site location is shown on the "Vicinity Map," Figure 1, and approximate locations of the explorations completed for this study are presented on the "Site Kirkland I Tacoma I Mount Vernon 425-827-7701 1 www.aesgeo.com Olympic View Drive Short Plat Limited Subsurface Exploration and Edmonds, Washington Infiltration Feasibility Assessment and Exploration Plan," Figure 2. An aerial site plan with LiDAR-based topography is included on the "Existing Site and Exploration Plan," Figure 3 and a LiDAR-based hill shade map is included on the "LiDAR" site plan, Figure 4. Current plans include construction of single-family homes on each of the two lots and an infiltration facilityto manage runoff from both of the parcels. The infiltration facility is anticipated to consist of an infiltration trench that would be located below a proposed driveway to be constructed on the western parcel (8354 Olympic View Drive) as show on Figure 2. Our study includes an infiltration feasibility assessment for the proposed infiltration trench to per City of Edmonds requirements and to discuss the potential for stormwater-infiltration downgradient impacts to the local aquifer and adjacent properties to the north. SUBSURFACE EXPLORATION Our field studies for this phase of work were conducted qin March 2022 and included excavation of two exploration pits (EP-1 and IT-1), an infiltration test (IT-1) in one of the exploration pits, and performing a slope reconnaissance. This work supplements the above -referenced geotechnical studies which included an exploration boring to 31.5 feet (July 1, 2019) and six exploration pits (September 6, 2005) to gain subsurface information about the site. The conclusions and recommendations presented in this letter -report are based, in part, on the explorations completed for this study. The number, locations, and depths of the explorations were completed within site and budgetary constraints. Because of the nature of exploratory work below ground, extrapolation of subsurface conditions between field explorations is necessary. It should be noted that differing subsurface conditions may be present due to the random nature of deposition and the alteration of topography by past grading and/or filling. The nature and extent of variations between the field explorations may not become fully evident until construction. If variations are observed at that time, it may be necessary to re-evaluate specific recommendations in this letter -report and make appropriate changes. Infiltration Test and Exploration Pits AESI observed excavation of one exploration pit and one Pilot Infiltration Test (PIT) on March 10, 2022. The pits were excavated by Vector One, LLC with a rubber -tracked excavator. These pits permitted direct, visual observation of subsurface conditions. Materials encountered in the exploration pits were studied and classified in the field by a geologist from our firm. All exploration pits were backfilled immediately after examination and logging. Samples were then transported to our laboratory for further visual classification and testing, as necessary. The various types of sediments, as well as the depths where the characteristics of the sediments changed, are indicated on the exploration logs presented in Appendix A. The depths indicated on the logs where conditions changed may represent gradational variations between sediment types. If changes occurred between sample intervals in our exploration pits, they were April 6, 2022 ASSOCIATED EARTH SCIENCES, INC. PELlih - 20190101 E002-002 Page 2 Olympic View Drive Short Plat Limited Subsurface Exploration and Edmonds, Washington Infiltration Feasibility Assessment interpreted. Our explorations were approximately located in the field by measuring from known site features. SUBSURFACE CONDITIONS Subsurface conditions at the project site were inferred from field explorations accomplished for this and previous studies, visual reconnaissance of the site, and review of selected applicable geologic literature. The feasibility of stormwater infiltration depends upon the presence of a suitable native receptor soil of sufficient thickness, extent, permeability, and vertical separation from groundwater. All explorations completed for this study generally encountered fill over glacially derived Vashon advance outwash sediments. Stratigraphy Fill At the existing ground surface, our explorations encountered approximately 2 feet of loose brown, fine to medium sand, with variable silt and gravel content and trace organics and debris. These materials are interpreted as fill soils placed during previous site development. Fill is expected to be found around existing structures, buried utilities, foundation/wall backfill areas, and beneath landscape improvements. Due to their variable silt content, highly variable composition, and lack of lateral continuity, fill soils are not a suitable stormwater infiltration receptor. Topsoil A layer of organic -rich, dark brown topsoil was encountered at all explorations underlying the existing fill. The encountered thickness of the topsoil was generally 8 inches. The topsoil included small to medium sized roots which extended downward into the underlying sediments. We interpreted these highly organic sediments to be the original ground surface prior to grading and filling at the site. Organic topsoil is not a suitable stormwater infiltration receptor. Vashon Advance Outwash Underlying the topsoil, our explorations encountered sediments interpreted to be Vashon advance outwash. The Vashon advance outwash was dense to very dense, grayish brown to brown, fine to medium sand, with variable silt content and trace gravel, with generally massive bedding. The Vashon advance outwash observed in our explorations included an approximately 2-foot-thick weathered horizon just below the topsoil, characterized by reddish brown oxidation and an increased fines content. The Vashon advance outwash sediments ranged from fine sand, some silt near the surface to fine to medium sand with trace silt near the bottom of the excavations at approximately 10 feet. We interpret these sediments to be representative of Vashon advance outwash. The Vashon advance outwash was deposited by meltwater streams April 6, 2022 ASSOCIATED EARTH SCIENCES, INC. PEL/ih-20190101E002-002 Page 3 Olympic View Drive Short Plat Limited Subsurface Exploration and Edmonds, Washington Infiltration Feasibility Assessment flowing from the advancing glacial ice during the early portion of the Vashon Stade of the Fraser Glaciation, approximately 12,500 to 15,000 years ago. Unsaturated Vashon advance outwash is a suitable stormwater infiltration receptor when present in sufficient vertical and lateral extent, and provided the recommendations contained in this letter -report are followed. Published Geologic and Soil Mapping Review Review of the regional geologic map titled Geologic Map of the Edmonds East and part of the Edmonds West Quadrangles, by J.P. Minard (1983) indicates that the subject site is underlain by Vashon advance outwash with Vashon lodgement till mapped nearby to the south. Our interpretation of subsurface conditions is in general agreement with the published geologic map of the area in that we encountered Vashon advance outwash in our explorations. Review of the U.S. Department of Agriculture (USDA) Soils Conservation Service (SCS), now referred to as Natural Resources Conservation Service (NRCS), Web Soil Survey indicates that the subject site is underlain by Alderwood gravelly sandy loam, 15 to 30 percent slopes. Alderwood series soils have a parent material of glacial lodgment till, which was not encountered within our explorations but is mapped nearby. Our interpretations of the soils encountered in our explorations are not in general agreement with the regional soils mapping. The soils encountered within our explorations would be more characteristic of Indianola or Everett Series soil series which have a parent material of glacial outwash. Hydrology Regional Groundwater The regional groundwater mapping (R.C. Newcomb, 1952, Ground -water Resources of Snohomish County, Washington: U.S. Geological Survey, Water -Supply Paper 1135, scale 1:62,500) indicates that groundwater within the advance outwash is present at about elevation 220 to 240 feet, or on the order of about 35 to 55 feet below the current ground surface. In addition, the mapping indicates that the direction of groundwater flow in the vicinity of the site is to the north. Local Groundwater No seepage was present at the time of digging in the exploration pits completed for this study. During our previous work at the site, AESI observed EB-1 (July 2019) advanced to a depth of 31.5 feet below ground surface. Groundwater was encountered within EB-1 at a depth of 22 feet below ground surface, an elevation of approximately 254 feet. At a site located about 2,000 feet east of the subject site, AESI has conducted continuous groundwater level monitoring of the Vashon advance outwash aquifer for several years, and we have observed that water levels fluctuate seasonally about 0.5 to 2.5 feet. For vertical groundwater separation considerations, based on our nearby groundwater level monitoring, we estimate that seasonal high groundwater levels on the subject site could be up to 3 feet higher than the water level encountered at the time of drilling in EB-1 in July 2019. April 6, 2022 ASSOCIATED EARTH SCIENCES, INC. PEL/ih-20190101E002-002 Page 4 Olympic View Drive Short Plat Limited Subsurface Exploration and Edmonds, Washington Infiltration Feasibility Assessment It should be noted that the depth or occurrence of groundwater seepage below the site may vary in response to such factors as changes in season, precipitation, and on- and off -site use. Explorations for this study were conducted in March 2022. Offsite Reconnaissance We conducted slope reconnaissance north of the subject site on public parkland to observe the existing slopes within the park and look for areas of groundwater seepage. In addition to our field observations, we reviewed LIDAR based topographic mapping of the site shown on Figure 3 and Figure 4. The topography of the park slopes down to the north, away from Olympic View Drive and includes slopes with inclinations ranging from 10 to 30 percent. During our reconnaissance, we observed areas of minor groundwater seepage within the ravines which drained to lower elevations, resulting in standing water in places. The elevation at which we encountered the groundwater seepage was relatively consistent and we interpreted this to be representative of the local groundwater table. The location of the seepages corresponded to elevations ranging from 205 to 225 feet and were generally 200 feet or more from the proposed location of the infiltration trench facility. We did not observe any signs of recent landslide activity or instability along the slopes. Due to weathering of the soils and the thick vegetation, it was difficult to classify the soil types along the slopes. The observed soils appeared to consist primarily of sand with some gravels which is texturally consistent with Vashon advance outwash. Based on our observations, it is our opinion that infiltration of storm water at the subject site will not adversely affect the stability of the terrain to the north of the site due to the size of the facility and the distance to areas of observed existing seepage. Laboratory Testing AESI performed grain -size analyses (sieves) on representative samples of the Vashon advance outwash sediments. The results are included in Appendix B and summarized below in Table 1 with soil descriptions based on ASTM International (ASTM) D-2487 Unified Soil Classification System (USCS). Table 1 Summary of Grain -Size Analysis Exploration Number Depth (feet) Geologic Unit USCS Soil Description Fines Content (%) IT-1 8 Vashon Advance Outwash Gravelly SAND, some silt (SP-SM) 7.1 IT-1 10 Vashon Advance Outwash SAND, trace gravel, trace silt (SP) 0.9 USCS = Unified Soil Classification System % = percent of total weight passing the U.S. No. 200 Sieve April 6, 2022 ASSOCIATED EARTH SCIENCES, INC. PELlih - 20190101 E002-002 Page 5 Olympic View Drive Short Plat Limited Subsurface Exploration and Edmonds, Washington Infiltration Feasibility Assessment INFILTRATION RATE DETERMINATION Infiltration Testing Procedures and Field Results Infiltration testing was conducted in order to obtain a representative infiltration rate for the proposed project using a method generally corresponding to the procedure described for the Small -Scale PIT in the 2017 City of Edmonds Stormwater Addendum. One low -head Small -Scale PIT (IT-1) was completed on March 10, 2022 at a depth of 8 feet below ground surface approximately 20 feet to the east of the location of the proposed infiltration system, as shown on Figure 2, to obtain a representative infiltration rate. The test was conducted by discharging water into a flat-bottomed pit of known dimensions for a "soaking period," to allow the receptor soils in the immediate vicinity of the pit to become saturated. After completion of the soaking period, water was discharged into the pit at a rate sufficient to maintain a head in the pit. Water for the testing was obtained from an on -site domestic water well with an integrated pumping system. During infiltration testing, water was discharged into the infiltration pit through a diffuser to minimize turbulence and scouring in the pit bottom. An electronic flow meter/totalizer assembly with instantaneous flow rate and total flow volume readouts was used to monitor the water discharge rate and total flow. Every 10 to 15 minutes, flow rates were recorded and water levels were measured with a staff gauge marked in 0.01-foot increments that was placed in the test pit prior to testing. Infiltration test details are summarized in Table 2. The total discharge time for the test at IT-1 was 6.5 hours. The flow rate to IT-1 was relatively constant and ranged from 0.5 to 0.6 gallons per minute (gpm) for most of testing period. During the last four hours of flow, a constant -head level of about 1-foot was maintained. Following completion of the constant -head test, the flow of water into the pit was discontinued and the rate of water level decline (falling -head) in the pit was monitored for about 1 hour. The field -based infiltration rate was 3.6 inches per hour (iph). Upon completion of the infiltration test, infiltration pit IT-1 was deepened to: 1) document the types of soils the water infiltrated through, and 2) identify any soil layers that would restrict the downward flow of infiltrating water. The material beneath the test surface consisted of generally similar fine to medium -grained Vashon advance outwash sediments, extending beyond the maximum explored depth of 10.5 feet. AESI observed increased moisture content below the infiltration test depth, indicating that the test water infiltrated downward to at least the total depth explored. Field infiltration data sheets are included in Appendix C. Analyses of infiltration testing data are discussed in the "Design Infiltration Rate Determination" section of this letter -report. April 6, 2022 ASSOCIATED EARTH SCIENCES, INC. PEL/ih-20190101E002-002 Page 6 Olympic View Drive Short Plat Limited Subsurface Exploration and Edmonds, Washington Infiltration Feasibility Assessment Table 2 Small -Scale Pilot Infiltration Test Summary Average Flow Field Rate during Final Field (Unfactored) (Unfactored) Test Test Area Hour of Testing Constant -Head Falling -Head Test Depth (square (gallons per Infiltration Rate Infiltration Rate Number (feet) feet) minute) (inches/hour) (inches/hour) IT-1 8 13.5 0.5 3.6 3.6 Design Infiltration Rate Determination The field -based infiltration rates presented in Table 2 are unfactored field infiltration rates and are therefore non -conservative for design purposes. The 2017 City of Edmonds Stormwater Addendum requires that the field -measured infiltration rate must then have various correction factors applied to account for site variability, number of tests conducted, type of field test, and the potential for long-term clogging due to siltation and bio-buildup. The correction factors used in the calculation and the resulting Ksat Design rate are described below. Ksatdesign = Ksatinitial * CFv * CFT * CFM Ksat, design: Represents the long-term design infiltration rate. Ksat, initial: Represents the uncorrected field -measured infiltration rate. Site variability and number of locations tested (CFI): Based on the relatively uniform subsurface conditions observed in our explorations in the proposed infiltration area, we consider the uncertainty at the site to be low and a partial correction factor of 0.8 was selected. Uncertainty of test method (CFr): Based on the use of 1 Small -Scale PIT, a partial correction factor of 0.5 is defined. Degree of influent control to prevent siltation and bio-buildup (Um): A partial correction factor of 0.9 is defined. The field -based infiltration rate was 3.6 iph. Therefore, Design Infiltration Rate = 3.6 inches per hour x 0.8 x 0.5 x 0.9 = 1.3 inches per hour. The correction factors and resulting design infiltration rate apply only to the proposed infiltration facility near IT-1 where unsaturated advance outwash consistent with the tested material is present at the base of any proposed infiltration best management practice (BMP). April 6, 2022 ASSOCIATED EARTH SCIENCES, INC. PEL/ih-20190101E002-002 Page 7 Olympic View Drive Short Plat Edmonds, Washington Limited Subsurface Exploration and Infiltration Feasibility Assessment CRITICAL AQUIFER RECHARGE AREAS AND GROUNDWATER PROTECTION The Edmonds City Code (ECC 23.60.010) defines Critical Aquifer Recharge Areas as the following: Critical aquifer recharge areas (CARAs) are those areas with a critical recharging effect on aquifers used for potable water as defined by WAC 365-190-030(2). CARAs have prevailing geologic conditions associated with infiltration rates that create a high potential for contamination of ground water resources or contribute significantly to the replenishment of ground water. CARAs are protected as critical areas under the Washington State Growth Management Act. However, no areas meeting criteria for CARAs exist in the vicinity of the city of Edmonds. Thus, additional specific provisions for protection of this critical area type are not provided within this title. The ECC specifies that no CARAs are present within the vicinity of the City of Edmonds. Review of the Washington State Department of Health Source Water Assessment Program (SWAP) Online Mapping Application indicates that no surface or groundwater resources are mapped within 2.5 miles of subject site. RECOMMENDATIONS AND CONCLUSIONS Based on our subsurface exploration, testing, and geologic interpretations, we conclude that infiltration of treated stormwater runoff via the currently proposed infiltration facility is feasible. The unweathered Vashon advance outwash was encountered at depths of 5 to 5.5 feet in our onsite explorations. Unsaturated Vashon advance outwash deposits are interpreted to be present to at least 10 feet below the facility base. There was adequate vertical separation from groundwater, in our opinion, based on the proposed infiltration facility floor elevation, groundwater levels observed at the time of drilling and during site reconnaissance, and comparisons with nearby groundwater level monitoring data. Long-term performance of infiltration facilities is improved by providing clean turbid -free water to the facility. Therefore, we recommend that all stormwater runoff be routed through treatment systems prior to entering the infiltration facilities. Infiltration Facility Subgrade Preparation The base of the infiltration facility must be excavated to remove the topsoil, any fill materials, and the overlying relatively finer -grained soils to expose the underlying relatively clean unweathered Vashon advance outwash granular sediments. From the results of the explorations, this depth is variable, but is generally 5 to 7 feet or less from existing grades and must be observed by AESI. We recommend using an excavator with a toothed bucket to strip and scarify the subgrade without tracking over it. If the excavation of the overlying finer -grained soils occurs to a greater depth than the design subgrade, the excavation should be backfilled with washed import free -draining aggregate. April 6, 2022 ASSOCIATED EARTH SCIENCES, INC. PELlih - 20190101 E002-002 Page 8 Olympic View Drive Short Plat Limited Subsurface Exploration and Edmonds, Washington Infiltration Feasibility Assessment Excavation of the overlying fill/fine-grained soils should be performed in a manner that does not disturb the underlying receptor horizon. Placement of the washed import free -draining aggregate within the infiltration facility footprint should be completed in a manner which minimizes impacts to the framework and density of the native soil. Use of heavy equipment in the areas proposed for infiltration has the potential to compact the subgrade and reduce infiltration potential. Immediately before placing aggregate, remove any accumulation of fine material (if present) with light equipment and scarify the subgrade. Construction activity on the surface that results in compaction of the native soil will have a detrimental effect on the infiltration rate. Due to natural variability of the subsurface conditions, the potential for field adjustments should be anticipated based on actual conditions encountered during construction. Depending on the season the infiltration facility is constructed, perched water should be anticipated. The contractor should be prepared to handle the perched water. Imported Fill for Infiltration Facilities Imported fill for the proposed underground infiltration facility will include washed 1 % inch to 3 inch gravel aggregate that will be placed within the facility footprint. The contractor should note that any proposed fill aggregate/soils must be provided to AESI a minimum of 72 hours prior to placement for conformance with project specifications. Care must be taken by using proper Temporary Erosion and Sedimentation Control (TESC) practices and management of the imported materials stockpile to ensure the imported materials are clean and free of fines. Stockpiled backfill materials must be protected from site soils and run-off from silt -contaminated surfaces. Contaminated backfill materials cannot be used in the infiltration facilities and will be rejected by AESI. Overflow Path We recommend an overflow path be specified such that runoff above the facility's design capacity does not cause flooding of a building or emergency access, erosion or downstream sedimentation, or slope failure. Protection of Facility Subgrade Once the facility is excavated and constructed, the contractor must provide temporary protection of the facilitv subgrade to keep the imported materials and subgrade free of water and fine-grained sediments. Uncontrolled runoff into the infiltration facility constitutes failure of the subgrade, requiring removal of all backfill materials and contaminated subgrade, and replacement with clean backfill materials. The infiltration facility must be kept isolated from influent flows until after the site has been stabilized, so that only clean water is introduced into the infiltration facility. April 6, 2022 ASSOCIATED EARTH SCIENCES, INC. PELlih - 20190101 E002-002 Page 9 Olympic View Drive Short Plat Limited Subsurface Exploration and Edmonds, Washington Infiltration Feasibility Assessment Plan Review and Construction Monitoring We are available to provide additional geotechnical/hydrogeologic consultation as the project design develops and possibly changes from that upon which this letter -report is based. We recommend that AESI perform a review of the plans prior to final design completion. In this way, our infiltration recommendations may be properly interpreted and implemented in the design. We are also available to provide geotechnical engineering and hydrogeologic monitoring services during construction of the infiltration BMP. The infiltration performance depends on verification of anticipated subsurface conditions, proper site preparation, backfill quality, and construction procedures. In addition, engineering decisions may have to be made in the field in the event that variations in subsurface conditions become apparent. Construction monitoring services are not part of the current scope of work. If these services are desired, please let us know and we will prepare a cost proposal. CLOSURE We appreciate the opportunity to be of service to you on this project. Should you have any questions regarding this letter -report or other geotechnical aspects of the project, please call us at your earliest convenience. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington eter E. Linton, L.G. Senior Staff Geologist Timothy J. PetCr, L.E.G., L.Hg. Senior Engineering Geologist Matthew A. Miller, P.E. Principal Engineer Attachments: Figure 1: Vicinity Map Figure 2: Site and Exploration Plan Figure 3: Existing Site and Exploration Plan Figure 4: LiDAR Appendix A: Exploration Logs Appendix B: Laboratory Test Results Appendix C: Infiltration Test Data April 6, 2022 PELlih - 20190101 E002-002 ASSOCIATED EARTH SCIENCES, INC. Page 10 t! fl, 1[ fit, 1 * mm .r r b r - jfi I •,I.1 1 - - q_,�. _ �`� - .•',1„�- 1 F _.fir. • - � �: _ �r . r � :• ten,. �� � V ,!:� - . vn. — •, Southwest County Park 20 ' - - • . ,I iri � Pis:•. - a S S o c l a t e d N jaearth sciences i n c o r p o r a t e d 2000 VICINITY MAP FEET DATA SOURCES I REFERENCES' OLYMPIC VIEW DRIVE SHORT PLAT USGS: 7.5' SERIES TOPOGRAPHIC MAPS. ESRIII-CUBEDINATIONAL NOTE: BLACK AND WHITE GEOGRAPHIC SOCIETY 2fl13 REPRODUCTION OF THIS COLOR E DM ❑N DS, WAS H INGTGN ORIGINALMAY REDUCE ITS SNOHOMISH CO: STREETS. CITY LIMITS. PARCELS, 3121 EFFECTIVENESS AND LEAD TO PR0,1 No 7 DATE' PIG LIRE: LOCATIONS AND DISTANCES SHOWN ARE APPROXIMATE INCORRECT INTERPRETATION 20190101 EO02 3122 1 a /r- =250. »(CENT, R 1 r — x - INFILTRAT]ON TRENCH 0% DEEP 00000, �IT-1 •� � r EP-1-- / FOOTINo DRAIN/ WALL y / WALL DRAIN CONNECTION Pvc \ "sue 1+3z03DOWNSPOUT I _ nNEC71ON 6.PVC TP-3� I � � I - - EB-1 I _� WALL To CONCRETE WALL— ,' EXTETIDED FOUNDATION //DTP.-4-- LEGEND Q SITE ■ EXPLORATION PIT, AESI, 2022 0 INFILTRATION TEST, AESI, 2022 O EXPLORATION BORING, AESI, 2019 ❑ EXPLORATION PIT, LIU & ASSOCIATES, INC., 2005 DATA SOURCES/REFERENCES: OMEGA ENGINEERING, INC., RITTER SP, GRADING & DRAINAGE PLAN, PAGE 5 OF 8, 10/11/16 SNOHOMISH CO: STREETS, PARCELS 3/21 KING CO: EAGLEVIEW TECHNOLOGIES, INC., AERIAL 2019 LOCATIONS AND DISTANCES SHOWN ARE APPROXIMATE C N A 0 20 FEET BLACK AND WHITE REPRODUCTION OF THIS COLOR ORIGINAL MAY REDUCE ITS EFFECTIVENESS AND LEAD TO INCORRECT INTERPRETATION a s s o c i a t e d earth sciences = i n c❑ r p❑ r a t e d SITE AND EXPLORATION PLAN OLYMPIC VIEW DRIVE SHORT PLAT EDMONDS, WASHINGTON PROJ NO. I DATE: FIGURE: 20190101 EO02 3/22 2 LEGEND SITE ■ EXPLORATION PIT, AESI, 2022 0 INFILTRATION TEST, AESI, 2022 O EXPLORATION BORING, AESI, 2019 ❑ EXPLORATION PIT, LIU & ASSOCIATES, INC., 2005 Q PARK PARCEL DATA SOURCES/REFERENCES: WA STATE LIDAR PORTAL: NORTH PUGET SOUND 2016 ACQUIRED MARCH - SEPT 2016, GRID CELL SIZE IS 3' CONTOURS FROM LIDAR SNOHOMISH CO: STREETS, PARCELS 3/21 KING CO: EAGLEVIEW TECHNOLOGIES, INC., AERIAL 2019 LOCATIONS AND DISTANCES SHOWN ARE APPROXIMATE m N A 0 80 FEET BLACK AND WHITE REPRODUCTION OF THIS COLOR ORIGINAL MAY REDUCE ITS EFFECTIVENESS AND LEAD TO INCORRECT INTERPRETATION a s s o c i a t e d jaearth Sciences In c❑ r p❑ rated LIDAR OLYMPIC VIEW DRIVE SHORT PLAT EDMONDS, WASHINGTON PROJ NO. I DATE: FIGURE: 20190101 EO02 3/22 4 APPENDIX A Exploration Logs U EZ °o Well -graded gravel and Terms Describing Relative Density and Consistency o p o o OW g ravel with sand, little to 2) Density SPT blows/foot w o no fines Very Loose 0 to 4 Coarse-4 to 10 o o o 0 o 0 0 o o o GP Poorly -graded gravel 0)Loose > U) c> o o - v, o �,o w Grained Soils Medium Dense 10 to 30 Test Symbols 0 0 o 0 0 0 o and gravel with sand, Dense 3o to 50 little to no fines Very Dense >50 G = Grain Size M = Moisture Content ° 0° 0 Silty gravel and silty 6 Z C LO o Consistency SPT(2�blows/foot Y A= Atterberg Limits c a S GM gravel with sand Very Soft 0 to 2 C = Chemical Fine - v ~ ` .Soft ° 0 ° 0 2 to 4 DID =Dry Density Grained Soils c E 0 .i Medium Stiff 4 to 8 K = Permeability g o Stiff 8 to 15 Clayey gravel and Very Stiff 15 to 30 N NI Gc clayey gravel with sand Hard >30 o L Component Definitions o Well -graded sand and t Descriptive Term Size Range and Sieve Number m SW sand with gravel, little Boulders Larger than 12" o Li u e to no fines Cobbles 3" to 12" m ;n a� _ eveeeveeee Gravel 3" to No. 4 (4.75 mm) Poorly -graded sand con c i °' A SP and sand with gravel, Coarse Gravel 3" to 3/4" Fine Gravel 3/4to No. 4 75 mm " 4 (� ) 4) c cn o v N o little to no fines Sand No. 4 (4.75 mm) to No. 200 (0.075 mm) 0 z Coarse Sand No. 4 (4.75 mm) to No. 10 (2.00 mm) 6 o y � SM Silty Sand and Medium Sand No. 10 (2.00 mm) to No. 40 (0.425 mm) silty sand with Fine Sand No. 40 (0.425 mm) to No. 200 (0.075 mm) N v c N o a tp.-::'::. gravel Silt and Clay Smaller than No. 200 (0.075 mm) (3) Estimated Percentage Moisture Content Na sc Clayey sand and co NI clayey sand with gravel Component Percentage by Weight Dry - Absence of moisture, Trace <5 dusty, dry to the touch Slightly Moist - Perceptible Silt, sandy silt, gravelly silt, moisture o ML silt with sand or gravel Some 5 to <12 Moist - Damp but no visible u7 c T w Modifier 12 to <30 water Clay Of low to medium o `—° (silty, sandy, gravelly) Very Moist - Water visible but d CL plasticity; silty, sandy, or not free draining z •= gravelly clay, lean clay Very modifier 30 to <50 Wet -Visible free water, usual) Y NE (silty, sandy, gravelly) from below water table 0- a == Organic clay or silt of low Symbols 2 — OL plasticity Blows/6" or 0 Sampler portion of 6" Cement grout o Type / i surface seal Elastic silt, clayey silt, silt 2.0" OD Sampler Type o o �, MH with micaceous or Split Spoon p Description (4) Bentonite seal � o or fine sand or Sampler p 3.0" OD Split -Spoon Sampler - :-= Filter pack with A o silt (SPT) 3.25" OD Split -Spoon Ring Sampler (4) . - ; . :: blank casing :: Clay of high plasticity, v) U o c � CH sandy or gravelly Clay, fat _ Bulk sample 3.0" OD Thin Wall Tube Sampler section Screened casing m E J clay with sand or ravel Y g (including Shelby tube) _ or Hydrotip =with filter pack U — c Grab Sample - End cap c ;% Organic clay or silt of o Portion not recovered OH medium to high (1) (4) Percentage by dry weight Depth of ground water plasticity (2) (SPT) Standard Penetration Test 1 ATD = At time of drilling ASTM D-1586 (3) ( ) Q Static water level (date) In General Accordance with w Peat, muck and other rn _ c a, 0 PT highly organic soils Standard Practice for Description (5) Combined USCS symbols used for and Identification of Soils (ASTM D-2488) fines between 5% and 12% Classifications of soils in this report are based on visual field and/or laboratory observations, which include density/consistency, moisture condition, grain size, and g plasticity estimates and should not be construed to imply field or laboratory testing unless presented herein. Visual -manual and/or laboratory classification 3 methods of ASTM D-2487 and D-2488 were used as an identification guide for the Unified Soil Classification System. T O! ° a s s o c i a t e d earth sciences EXPLORATION LOG KEY FIGURE Al N o i n c o r p o r a t e d a assaClaIeC Exploration Borin e art h s c i e n cc s Project Number Exploration Number Sheet incorporalec 190101EO01 EB-1 1of1 Project Name Olympic View Drive Short Plat Ground Surface Elevation (ft) —276 Location Edmonds, WA Datum NAVD AS Driller/Equipment Environmental Drilling Inc. / Track Rig Date Start/Finish 7/1/1 Q 7/1/1 P Hammer Weight/Drop 140# / 30 Hole Diameter (in) F �5 cC Ch E .2 5 cL c .O a) n � > J CO U) 3 Blows/Foot w d) a S `a �, O u) o m m p� T K DESCRIPTION " -C ° 10 20 30 40 ` Forest Duff - 6 inches Topsoil - 6 inches Vashon Advance Outwash S-1 Slightly moist, light brown, fine to medium SAND, some silt (SP). 5 A 2 5 S 2 Moist, light brown, silty, fine SAND, trace gravel; faintly stratified (SM). 18 A " 0/ 50/ 10 Moist, grayish brown, fine to medium SAND, some silt to silty; cemented 18 S-3 sand layer (0.5 to 1 inch thick) (SP-SM). 24 A L55 31 15 Moist, grayish brown, fine to medium SAND, some silt to silty; cemented 15 S-4 sand layers (0.5 to 1 inch thick) (SP-SM). 24 A L54 30 20 Verymoist to wet at sampler tip, grayish brown, silty, medium to coarse 27 S-5 :. SAND, trace gravel; massively bedded silt interbed (2 inches thick) at 47 AL91 sampler tip (SM). 44 t 25 Wet, grayish brown, silty, fine to medium SAND, trace gravel (SM). 25 S 6 ': 45 50/ " 0/ " 30 Wet, grayish brown, silty, fine to medium SAND (SM). 6 S-7 30 A L50/ " 0/ " Bottom of exploration boring at 31.5 feet. Groundwater encountered at 22 feet. Sampler Type (ST): m 2" OD Split Spoon Sampler (SPT) ❑ No Recovery M - Moisture Logged by: JG m 3" OD Split Spoon Sampler (D & M) Ring Sample Q Water Level Q Approved by: JHS ® Grab Sample 0 Shelby Tube Sample 1 Water Level at time of drilling (ATD) a s s❑❑, a c e d Exploration Pit EP-1 Olympic View Drive Short Plat Sheet: 1 of 1 e a r t h s c i e n c e s OT Incorporated Edmonds, WA Date: 3/10/22 Logged By: PL 20190101EO02 Total Depth (ft): 10 Approved By: JHS Q Description v Elev.: ft NAVD 88 ° Fill Loose to medium dense, moist, brown, fine SAND, some silt, trace gravel (SP-SM). Loose, moist, dark brown, silty, fine SAND, trace gravel; abundant roots (SM). z.s Weathered Vashon Advance Outwash Medium dense, moist, reddish brown, fine SAND, some silt, trace gravel; scattered roots; massive (SP-SM). s Vashon Advance Outwash Medium dense to dense, moist, brown, fine SAND, trace to some silt; massive (SP-SM). 7.s Medium dense to dense, moist, brown, fine sand, some silt; massive (SP-SM). Dense, moist, brown, fine SAND, trace to some silt; massive (SP-SM). io No seepage. No caving. iz.s is i7.s zo Occnriatarl Farth rriPnrac Inr a s s❑❑ f a t e d Exploration Pit IT-1 Olympic View Drive Short Plat Sheet: 1 of 1 e a r t h s c i e n c e s OT Incorporated Edmonds, WA Date: 3/10/22 Logged By: PL 20190101EO02 Total Depth (ft): 10.5 Approved By: JHS Q Description v Elev.: ft NAVD 88 ° Fill Loose, moist, brown, fine SAND, some silt, some gravel; chaotic texture (SM). Loose, moist, dark brown, silty, fine SAND, trace gravel; abundant organics and roots (SM). z.5 Weathered Vashon Advance Outwash Medium dense, moist, reddish brown, fine SAND, some silt, trace gravel; massive (SP-SM). s Vashon Advance Outwash Medium dense to dense, moist, brown, fine SAND, some silt; massive (SP-SM). 7.5 Dense, wet, brown, gravelly, fine to medium SAND, some silt; massive (SP-SM). Dense, moist, grayish brown, fine to medium SAND, trace silt, trace gravel; massive (SP). io No seepage. No caving. Infiltration test performed at 7.5 feet. iz.s is i7.s zo Occnriatarl Farth rriPnrac Inr rf � `+) 274 266 IF 288 290 r + 294 l' _ 296 J A us -mil ( �IDU S� f Jr, + _ r SITE AND EXPLORATION LOCATION PLAN LIU & ASSOCIATES, INC. 3-LOT SHORT PLAT 8364 OLYMPIC VIEW DRIVE Geotechnical Engineering Engineering Geology Earth Science EDMONDS, WASHINGTON JOB NO, 5A112 1 DATE 9/23/2005 7F PLATE 2 UNIFIED SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP GROUP NAME SYMBOL GRAVEL CLEAN GW WELL -GRADED GRAVEL, FINE TO COARSE GRAVEL GP POORLY -GRADED GRAVEL COARSE- MORE THAN 50% of GRAVEL GRAVEL WITH GM SILTY GRAVEL GRAINED COARSE FRACTION SOILS RETAINED ON NO. 4 SIEVE FINES GC CLAYEY GRAVEL SAND CLEAN SW WELL -GRADED SAND, FINE TO COARSE SAND SP POORLY -GRADED SAND MORE THAN 50% MORE THAN 50% OF SAND SAND WITH SM SILTY SAND RETAINED ON THE COARSE FRACTION NO. 200 SIEVE PASSING NO. 4 SIEVE FINES SC CLAYEY SAND FINE- SILT AND CLAY INORGANIC ML SILT CL CLAY GRAINED LIQUID LIMIT ORGANIC OL ORGANIC SILT, ORGANIC CLAY SOILS LESS THAN 50% MORE THAN 50% SILTY AND CLAY INORGANIC MH SILT OF HIGH PLASTICITY, ELASTIC SILT CH CLAY OF HIGH PLASTICITY, FAT CLAY PASSING ON THE LIQUID LIMIT ORGANIC OH ORGANIC SILT, ORGANIC SILT NO. 200 SIEVE 50% OR MORE HIGHLY ORGANIC SOILS PT PEAT AND OTHER HIGHLY ORGANIC SOILS NOTES: SOIL MOISTURE MODIFIERS: 1. FIELD CLASSIFICATION IS BASED ON VISUAL EXAMINATION DRY - ABSENCE OF MOISTURE, DUSTY, DRY TO OF SOIL IN GENERAL ACCORDANCE WITH ASTM D2488-83. THE TOUCH 2. SOIL CLASSIFICATION USING LABORATORY TESTS IS BASED SLIGHTLY MOIST - TRACE MOISTURE, NOT DUSTY ON ASTM D2487-83. MOIST - DAMP, BUT NO VISIBLE WATER 3. DESCRIPTIONS OF SOIL DENSITY OR CONSISTENCY ARE VERY MOIST - VERY DAMP, MOISTURE FELT TO THE TOUCH BASED ON INTERPRETATION OF BLOW -COUNT DATA, VISUAL WET - VISIBLE FREE WATER OR SATURATED, APPEARANCE OF SOILS, AND/OR TEST DATA. USUALLY SOIL IS OBTAINED FROM BELOW WATER TABLE LIU & ASSOCIATES' INC. UNIFIED SOIL CLASSIFICATION SYSTEM Geotechnical Engineering Engineering Geology - Earth Science PLATE 3 ii GAS I nnnprl Rv Iql Date: 9/6/2005 Ground El. 272.6' ± Depth ft. V V USCS CLASS. Soil Description Sample No. w % Other Test 1 OL Brush and duff on surface Dark -brown, lose, organic, silty fine SAND, with roots to 1.25-inch- diameter, dry (TOPSOIL) 2 3 Light -brown, loose, silty fine SAND, trace gravel, and occasional SM 4 boulder to 12 inches in size, dry 5 6 SP Light -brown to light -gray, medium -dense, fine to medium, trace gravel, slightly moist (fresh ADVANCE OUTWASH) 7 8 SW Light -gray, dense, fine to coarse SAND, trace to some gravel, slightly moist (fresh ADVANCE OUTWASH) 9 10 Test pit terminated @ 10.0 ft, groundwater not encountered. 11 TEST PIT NO. 6 r,rlrlAH R„• I.qI Date: 9/6/2005 Ground El. 277.5' ± Depth USCS Sample w Other ft. CLASS. Soil Description No. % Test OL Brush and duff on surface 1 Dark -brown, lose, organic, silty fine SAND, with roots to 1.5-inch- diameter, dry (TOPSOIL) 2 SM Light -brown, loose, silty fine SAND, trace gravel and occasional 3 boulder to 12 inches in size, dry 4 SP Light -brown to light -gray, medium -dense, fine to medium SAND, 5 trace to some gravel, slightly moist (fresh ADVANCE OUTWASH) 6 SW Light -gray, dense to very -dense, fine to coarse SAND, trace to 7 some gravel, moist (fresh ADVANCE OUTWASH) 8 9 Test pit terminated @ 8.0 ft, groundwater not encountered. 10 LIU & ASSOCIATES, INC. Geotechnical Engineering Engineering Geology Earth Science TEST PIT LOGS 3-LOT SHORT PLAT 8364 OLYMPIC VIEW DRIVE EDMONDS, WASHINGTON APPENDIX 6 Laboratory Test Results 0-1 W Z V_ Z W U 0-1 0_ 100 90 80 70 60 50 40 30 20 10 In Particle Size Distribution Report _ o00 100 10 1 0.1 0.01 0.001 GRAIN SIZE - mm. %+3„ % Gravel % Sand % Fines Coarse Fine Coarse Medium Fine Silt Clay 0.0 7.0 17.4 8.7 28.3 31.5 7.1 TEST RESULTS Opening Percent Spec." Pass? Size Finer (Percent) (X=Fail) 2" 100.0 1.5" 94.0 V 93.0 3/4" 93.0 5/8" 91.4 1/2" 88.9 3/8" 85.7 #4 75.6 #8 68.3 #10 66.9 #20 57.4 #40 38.6 #60 19.4 #100 11.1 #200 7.1 #270 5.7 (no specification provided) Location: Onsite - Vashon Advance Outwash Sample Number: IT-1 Depth: 8' a 8 8 o c i a t e e a r t h s c i e n c e incorporate Material Description gravelly SAND, some silt Atterberg Limits (ASTM D 4318) PL= NP LL= NV Pl= Classification USCS (D 2487)= SP-SM AASHTO (M 145)= A-1-b Coefficients D90= 14.0438 D85= 9.0502 D60= 0.9995 D50= 0.6100 1330= 0.3398 D15= 0.2053 D10= 0.1305 Cu= 7.66 Cc= 0.89 Remarks Date Received: 3/14/2022 Date Tested: 3/18/2022 Tested By: Cl Checked By: PL/TP Title: Client: Vector One, LLC Project: Olympic View Drive Short Plat Date Sampled: 3/10/2022 0-1 W Z Z W U 0-1 0_ 100 90 80 70 60 50 40 30 20 10 In Particle Size Distribution Report 000 i i i i i i i 100 10 1 0.1 0.01 0.001 GRAIN SIZE - mm. %+3„ % Gravel % Sand % Fines Coarse Fine Coarse Medium Fine Silt Clay 0.0 0.0 0.3 1.0 40.0 57.8 0.9 TEST RESULTS Opening Percent Spec." Pass? Size Finer (Percent) (X=Fail) 3/8" 100.0 #4 99.7 #8 98.9 #10 98.7 #20 92.8 #40 58.7 #60 20.0 #100 4.2 #200 0.9 #270 0.6 (no specification provided) Location: Onsite - Vashon Advance Outwash Sample Number: IT-1 Depth: 10' a 8 8 o c i a t e e a r t h s c i e n c e incorporate Material Description SAND, trace gravel, trace silt Atterberg Limits (ASTM D 4318) PL= NP LL= NV PI= Classification USCS (D 2487)= SP AASHTO (M 145)= A-3 Coefficients D90= 0.7704 D85= 0.6727 D60= 0.4327 D50= 0.3788 D30= 0.2918 D95= 0.2262 D10= 0.1978 Cu= 2.19 Cc= 1.00 Remarks Date Received: 3/14/2022 Date Tested: 3/18/2022 Tested By: Cl Checked By: PL/TP Title: Client: Vector One, LLC Project: Olympic View Drive Short Plat Date Sampled: 3/10/2022 APPENDIX C Infiltration Test Data Project Name: Olympic View Drive Short Plat Water Source: Hose Bib Project Number: 20190101E002 Meter: AESI FM#1 Date: 3/10/2022 Pit Area (sq. feet): -4.5' x 3.0' _ -13.5' Weather: PC, 40's Ring Area (sq. feet): NA Test No.: IT-1 I Test Depth (feet): 17.5 Performed By: PEL Receptor Soils: jAdvance Outwash Time (24-hr) Flow Rate (gpm) Stage (feet) Totalizer (gallons) Comments 8:24 2.95 0 0 Flow on 8:30 2.83 0.24 17.4 8:34 2.83 0.26 30.1 increased flow 8:45 3.49 0.54 67 9:00 3.51 0.78 119 9:15 3.51 1.00 172 reduced flow 9:22 2.46 1.10 190 minor caving from south wall, reduced flow 9:30 2.00 1.16 206 reduced flow 9:45 1.08 1.14 223 10:00 1.08 1.14 239 reduced flow 10:15 0.88 1.16 252 10:17 0.88 1.16 254 reduced flow 10:30 0.50 1.10 261 10:45 0.48 1.06 268 11:00 0.48 1.02 276 increased flow 11:15 0.61 1.00 285 11:23 0.61 1.00 290 water off,bucket test mini -falling head 11:32 0 0.96 290 11:39 0 0.92 290 11:42 0 0.90 290 11:45 0 0.88 300 water on 12:00 0.59 0.90 309 12:15 0.60 0.92 317 12:30 0.50 0.96 326 decreased flow 12:45 0.50 0.98 334 13:00 0.50 1.00 342 13:15 0.50 1.00 349 13:30 0.51 1.00 357 13:45 0.50 1.00 364 14:00 0.50 1.02 372 14:10 0.50 1.02 377 14:20 0.50 1.02 382 14:30 0.50 1.02 387 14:40 0.50 1.02 392 14:50 0.50 1.04 397 15:00 0.50 1.04 402 Flow off, begin falling head 15:10 0.98 15:18 0.94 15:26 0.90 15:36 0.86 15:45 0.82 15:49 0.80 15:53 0.78 15:57 0.76 16:00 0.74 End falling head Average Infiltration Rate (in/hr) during last hour of inflow: 3.6 Average Infiltration Rate (in/hr) during falling head: 3.6 Note: Meter zeroed at start of test. Ran low flow meter (0.3-3gpm) for the full duration of the test. Shut down flow at 11:23 for bucket test, mini falling head resulted in a 3.9 in/hr rate (0.12 feet in 22 minutes) minor caving changed water level by approximately 0.05 feet at 9:22