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Preliminary Technical Information Report revised dated August 27, 2019Company, Inc. Preliminary Technical Information Report Village Green of Federal Way Buildings F-J, Memory Care (Building K), 17 Cottages, Process 4 Land Use Review Prepared: November 8, 2018 Revised: August 27, 2019 DCI Project: 98480.6 DUNCANSON 145 SW 155th Street Suite 102 Seattle, Washington 98166 Village Green of Federal Way DCI 98480.6 Table of Contents Section 1 – Project Overview ........................................................................................................................ 3 Section 2 – Conditions and Requirements Summary ................................................................................. 14 Section 3 – Offsite Analysis ......................................................................................................................... 17 Section 4 – Flow Control, LID, & Water Quality Facility Analysis & Design ................................................ 27 Section 5 – Conveyance System Analysis and Design ................................................................................. 32 Section 6 – Special Reports and Studies ..................................................................................................... 34 Section 7 – Other Permits ........................................................................................................................... 74 Section 8 – CSWPP Plan Analysis and Design.............................................................................................. 76 Section 9 – Bond Quantities, Facility Summaries, and Declaration of Covenant ....................................... 78 Section 10 – Operations and Maintenance Manual ................................................................................... 80 Appendix A ‐ WWHM Report 82 2 Village Green of Federal Way DCI 98480.6 Section 1 Project Overview 3 Village Green of Federal Way DCI 98480.6 Section 1 – Project Overview This project is development of 5 apartment style, independent/assisted living buildings; a 40-unit memory care building and 13 new independent living cottages. In total approximately 227 new senior housing units are proposed. The project is divided into two Threshold Discharge Areas (TDA), coinciding very closely with the two separate tax parcels. TDA 1 is the eastern portion of the site, which includes the 5 apartment style buildings (Buildings F – J). TDA 2 is the western portion of the site containing the cottage units and memory care building (Building K). TDA 1 TDA 1 is mostly vacant land, much of which is forested. A portion of TDA 1 is a large grassy area that was previously cleared and graded as part of previous development on the Village Green campus constructed in the mid to late 1990s. TDA 1 also contains one leg of a paved, looped driveway and a gravel drive and parking area also constructed under previous approvals from the late 1990s through 2008. Ground slopes in TDA 1 are on the order of 2 to 10%, and generally draining to the northeast. Soils are mostly till with some areas of outwash as discussed further in the geotechnical report. A detention/wet pond was constructed to serve the anticipated development on TDA 1; however, flow control and water quality standards have evolved over the last 20 year such that some expansion and retrofitting will be required. Also, implementation of LID is also now required. Further discussion of additional stormwater improvements are included in Sections 5. A stormwater colletion and conveyance system is provided through the downstream property to the stormwater ponds. TDA 2 TDA 2 is the western portion of the site. Roads, stormwater facilities, utilities and grading within TDA 2 was constructed around 2008 to create ready to build sites for the cottage units. Only building sites and areas to remain undisturbed remain forested. TDA 2 is served by a pre- settling/wetpond followed by a “full” infiltration pond. It is the full infiltration from this subbasin that separates TDA 2 from TDA 1. Current water quality standard are achieved by the wetpond followed by soil treatment in the infiltration pond. Current flow control standards are achieved by fully infiltrating stormwater runoff from the TDA. The memory care building represents an approximate 9,000 SF increase in impervious area over the original design. To offset this increase, two of the remaining cottage buildings are designed to include full infiltration drywells. These improvements were approved by the City in 2018. Refer to Section 5 for additional discussion. Included are Figures 1.1 – Technical Information Report Worksheet, 1.2 – Vicinity Map, 1.3.1 – TDA 1 Basin Map, 1.3.2 – TDA 2 Basin Map and 1.4 – Soils Map. This report is intended as a preliminary stage TIR including the required off-site analysis. It also contains a preliminary hydrologic analysis used to develop a conceptual drainage plan. This report does not include the detailed design of all drainage components, however, it does contain sufficient detail for assessing the existing and proposed drainage characteristics. 4 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner ___________________________ Phone _________________________________ Address _______________________________ _______________________________________ Project Engineer _________________________ Company ______________________________ Phone _________________________________ Project Name _________________________ DPER Permit # ________________________ Location Township ______________ Range ________________ Section ________________ Site Address __________________________ _____________________________________ Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS Landuse (e.g.,Subdivision / Short Subd. / UPD) Building (e.g.,M/F / Commercial / SFR) Clearing and Grading Right-of-Way Use Other _______________________ DFW HPA COE 404 DOE Dam Safety FEMA Floodplain COE Wetlands Other ________ Shoreline Management Structural Rockery/Vault/_____ ESA Section 7 Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review (check one): Date (include revision dates): Date of Final: Full Targeted Simplified Large Project Directed __________________ __________________ __________________ Plan Type (check one): Date (include revision dates): Date of Final: Full Modified Simplified __________________ __________________ __________________ Part 6 SWDM ADJUSTMENT APPROVALS Type (circle one): Standard / Experimental / Blanket Description: (include conditions in TIR Section 2) ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Approved Adjustment No. ______________________ Date of Approval: ______________________ 2016 Surface Water Design Manual 4/24/20161 X 5 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: _______________________ Completion Date: _______________________ Describe: _________________________________ _________________________________________ _________________________________________ Re: KCSWDM Adjustment No. ________________ Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan : ____________________________________________________________________ Special District Overlays: ______________________________________________________________ Drainage Basin: _____________________________________________________________________ Stormwater Requirements: ____________________________________________________________ Part 9 ONSITE AND ADJACENT SENSITIVE AREAS River/Stream ________________________ Lake ______________________________ Wetlands ____________________________ Closed Depression ____________________ Floodplain ___________________________ Other _______________________________ _______________________________ Steep Slope __________________________ Erosion Hazard _______________________ Landslide Hazard ______________________ Coal Mine Hazard ______________________ Seismic Hazard _______________________ Habitat Protection ______________________ _____________________________________ Part 10 SOILS Soil Type _________________ _________________ _________________ _________________ Slopes _________________ _________________ _________________ _________________ Erosion Potential _________________ _________________ _________________ _________________ High Groundwater Table (within 5 feet) Other ________________________________ Sole Source Aquifer Seeps/Springs Additional Sheets Attached 2016 Surface Water Design Manual 4/24/201626 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE Core 2 – Offsite Analysis_________________ Sensitive/Critical Areas__________________ SEPA________________________________ LID Infeasibility________________________ Other________________________________ _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 8 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet) Level: 1 / 2 / 3 or Exemption Number ____________ Flow Control BMPs _______________________________ Conveyance System Spill containment located at: _________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Water Quality (include facility summary sheet) Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog or Exemption No. ______________________ Landscape Management Plan: Yes / No Special Requirements (as applicable): Area Specific Drainage Requirements Type: CDA / SDO / MDP / BP / LMP / Shared Fac. / None Name: ________________________ Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): ______________ Datum: Flood Protection Facilities Describe: 2016 Surface Water Design Manual 4/24/201637 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Source Control (commercial / industrial land use) Describe land use: Describe any structural controls: Oil Control High-use Site: Yes / No Treatment BMP: ________________________________ Maintenance Agreement: Yes / No with whom? ____________________________________ Other Drainage Structures Describe: Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION Clearing Limits Cover Measures Perimeter Protection Traffic Area Stabilization Sediment Retention Surface Water Collection Dewatering Control Dust Control Flow Control Protection of Flow Control BMP Facilities (existing and proposed) Maintain BMPs / Manage Project MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION Stabilize exposed surfaces Remove and restore Temporary ESC Facilities Clean and remove all silt and debris, ensure operation of Permanent Facilities, restore operation of Flow Control BMP Facilities as necessary Flag limits of SAO and open space preservation areas Other ______________________ Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Type/Description Water Quality Type/Description Detention Infiltration Regional Facility Shared Facility Flow Control BMPs Other ________________ ________________ ________________ ________________ ________________ ________________ Vegetated Flowpath Wetpool Filtration Oil Control Spill Control Flow Control BMPs Other ________________ ________________ ________________ ________________ ________________ ________________ ________________ 2016 Surface Water Design Manual 4/24/20164 X X X X X X X X X X 8 9 Figure 1.2 – Vicinity Map Site @ 1st Avenue South & SW 356th Street Scale: N/A Drawn: JMK Job No: 98480.2 TDA 1 TDA 2 10 Job No. 98480.6Drawn: HMDScale: 1" = 100'Figure 1.3.1 - Village Green TDA 1 Basin MapCivil Engineering · Surveying · Land PlanningD U N C A N S O N C O M P A N Y, I N C.145 SW 155th Street, Suite 102Seattle, Washington 98166Phone 206.244.4141Fax 206.244.445511 SNS N S Job No. 98480.6Drawn: HMDScale: 1" = 100'Figure 1.3.2 - TDA 2 Basin MapCivil Engineering · Surveying · Land PlanningD U N C A N S O N C O M P A N Y, I N C.145 SW 155th Street, Suite 102Seattle, Washington 98166Phone 206.244.4141Fax 206.244.445512 Figure 1.4 – Soils Map EvB = Everett Gravelly Sandy Loam, 0-5% Slopes Scale: NTS Drawn: HMD Job No: 98480.6 13 Village Green of Federal Way DCI 98480.6 Section 2 Conditions and Requirements Summary 14 Village Green of Federal Way DCI 98480.6 Section 2 – Conditions and Requirements Summary The City of Federal Way requires compliance with the 2016 King County Surface Water Design Manual (KCSWDM) and the City of Federal Way Addendum to KCSWDM. This report follows the format specified in the KCSWDM. This Section describes how the Project will meet the Manual’s Core and Special Requirements. Core Requirements: 1. Discharge at the Natural Location The site runoff is separated into two TDAs. Runoff from TDA 1 drains to the northeast and is collected by the catch basins and pipe network in the existing Village Green campus. A storm drain is stubbed into this site for a point of connection for the proposed development to maintain the point of discharge. Runoff from TDA 2 is collected by the catch basin and pipe system constructed as part of the Cottages West development. Lot drain stubs are provided to each of the cottage and memory care building sites, which will be used to maintain the point of discharge. See Figure 3.1 – Offsite Analysis Map for more information. 2. Offsite Analysis A Level 1 offsite analysis has been performed for this project. See Section 3 for more information. 3. Flow Control The site is located in a Conservation Flow Control area. Flow control will be provided by LID BMPs, the existing (modified) detention pond and the existing infiltration pond. See Section 4 for more information. 4. Conveyance System Appropriate conveyance calculations will be included in Section 5 at the final engineering stage. 5. Erosion and Sediment Control ESC measures will conform to the 2016 KCSWDM. ESC plans will be provided at the final engineering/building permit stage for each building. 6. Maintenance and Operations A maintenance and operations manuals are already in place for the stormwater facilities. These documents will be amended as needed at the final engineering/building permit stage. 7. Financial Guarantees and Liability The project owner will provide appropriate financial guarantees and liability insurance prior to construction. 8. Water Quality The site is in the Enhanced Basic Water Quality Treatment area. See Section 4 for additional information. 9. Flow Control BMPs 15 Village Green of Federal Way DCI 98480.6 Flow Control BMPs are required in TDA 1 and are generally depicted on the site plan. Impervious surfaces in TDA 2 is served by an infiltration facility and are exempt from the BMP requirement. However, soil amendment is required. See Section 4 for additional information. Special Requirements: 1. Other Adopted Area-Specific Requirements The site is in the Hylebos Creek Basin. The City’s flow control and water quality standards meet or exceed the recommendations of the basin plan. 2. Flood Hazard Area Delineation This site does not lie within the 100-year flood plain. 3. Flood Protection Facilities This requirement does not apply. 4. Source Control Source Control is required. Applicable structural and non-structural source controls are discussed in Sections 4 and 8. 5. Oil Control The site is not a high-use site. This requirement does not apply. 16 Village Green of Federal Way DCI 98480.6 Section 3 Offsite Analysis 17 Village Green of Federal Way DCI 98480.6 Section 3 – Offsite Analysis Task 1 - Study Area Definition & Maps The study area was defined by the site topography using City of Federal Way’s GIS maps. The study area includes the site and downstream flowpaths. See Figure 3.1 – Offsite Analysis Map for more information. Task 2 - Resource Review 1. Adopted Basin Plan BW-2: Basinwide Onsite Detention Standard; which is Level 1 Flow Control (KCRTS) – Match predeveloped 2- and 10- year peak flow rates. Note that this is a dated standard and current City Flow and Water Quality standards exceed the Basin Plan requirements. 2. Finalized Drainage Studies Not applicable. 3. Basin Reconnaissance Summary Reports This project is in the Hylebos Creek Basin and contributes to Tributary 0014B. 4. Critical Drainage Area Maps See Figure 3.2 – Critical Areas Map for the offsite wetland location. 5. FEMA Maps Not applicable. 6. Other Offsite Analyses The downstream analyses for the Village Green Phase I, Tuscany Woods and Cottages West projects were consulted. These projects include the subject property and adjoin the site to the west. These downstream analyses did not reveal any problems or require any special mitigation. 7. Sensitive Areas Folio A map detailing Federal Way’s critical areas in the site vicinity is included as Figure 3.2. . 18 Village Green of Federal Way DCI 98480.6 8. Drainage Complaints and Studies Drainage complaint summaries were obtained from King County. See Figure 3.1 – Offsite Analysis Map. The drainage complaint parcels are shaded orange and have been assigned a number (DC-2 for example). Two drainage complaints were found to be in the downstream flowpath. Below is a description of how each drainage complaint has been addressed. DC-1: 1987-0727 Parcel #292104-9029. This drainage complaint was regarding an old drainage pipe with constriction issues. This complaint is more than 10 years old, therefore it is not applicable. DC-2: 1989-0448 Parcel #292104-9030. This drainage complaint was regarding drainage issues with the Sunrise Methodist Church construction. This complaint is more than 10 years old, therefore it is not applicable. 9. USDA Soils Survey See Figure 1.4 – Soils Map. Soils noted as Everett Gravelly Sandy Loam. 10. Wetlands Inventory No onsite wetlands. See Figure 3.2 for the locations of offsite wetlands. 11. Migrating River Studies Not applicable. 12. WSDOE Water Quality Atlas Ecology’s Water Quality Atlas was consulted to investigate for impaired waters. The tributary to West Hylebos Creek, located downstream from the Site was listed as having temperature and dissolved oxygen impairments. See Task 5 below. 19 Village Green of Federal Way DCI 98480.6 Task 3 - Field Reconnaissance A current field reconnaissance was conducted on August 5, 2019. Weather conditions were sunny and dry. While not part of this specific investigation, several other site visits were conducted through 2017 and 2018, including during the wet season and also after precipitation events. The downstream flow paths were observed for ¼ mile. A description of the various downstream runoff system components is contained under Task 4 below. Task 4 - Drainage System Description and Problem Screening TDA 1 Component 1A ~ Pipe Flow (0’ – 880’) Runoff exits the site via a storm drain system that was stubbed into the site as part of earlier phases of the Village Green retirement community (Phase I-1996 and Buildings D and E of the original Phase II plan-1998). This drainage system consists of catch basins and 8” to 18” pipes with slopes generally between 1 and 10%. Runoff is routed through this system until it reaches a detention/wet pond, which was also part of the original Village Green development. Pipes and catch basins were clean. No evidence of flooding or erosion problems was observed. Component 1B ~ Detention/Wet Pond & Bioswale (880’ – 1,380’) Runoff outlets into a stormwater facility located in the northeast corner of the Village Green Phase I site. The facility is a multi-cell, flow through, combined detention wetpond followed by a biofiltration swale. The facility appears to be in a fully functional condition and has become well vegetated. Some trash (shopping carts, cans, bottles, etc.) has accumulated, particularly near 1st Avenue S. Weeds and brush have grown around some of the inlet and outlet pipes. No other problems or evidence of flooding or erosion were observed. Component 1C ~ Pipe Flow (1,380’ – 1,825’) Runoff from the bioswale is collected into a pipe and catch basin system, which routes runoff east to 1st Avenue S, then north under the west shoulder of 1st Avenue S. This drainage system consists of catch basins and 18” CPEP and concrete pipes. Runoff is routed north through this system until it reaches the sag location along 1st Avenue South. No evidence of flooding or erosion problems was observed. At this sag location, the pipe system connects with the cross culvert under 1st Avenue S and combines with the overflow flowpath from TDA 2. Component E ~ Culvert (1,825’– 1,865’) TDA 1 runoff is routed east under 1st Avenue South. The culvert is a 48” CMP with a slope of ±2%. Several shopping carts and other debris were present in the channel at the inlet of the culverts. The pipe appeared to be clean, with only minor sedimentation. A small base flow was observed. The outlet end (east side of 1st Ave S) was partially submerged as a result of downstream conditions. Long term, natural sedimentation within the wetland below may explain why the 20 Village Green of Federal Way DCI 98480.6 culvert outlet is partially submerged, or it may have been constructed in that manner, or both. Velocities through the pipe appear to be sufficient to keep the outlet clear so as not to cause plugging. No other problems or evidence of flooding or erosion problems were observed. Component F ~ Sheet Flow (1,865’+) Runoff outlets east from the culvert and into a city identified wetland. A concentrated flowpath was observed for a several yards, but then flows disperse into the heavily vegetated wetland. TDA 2 Component 2A ~ Pipe Flow (0’ – 80’) Runoff exits the site along the northwestern property line and is collected by the drainage system of Cottages West and is routed north. This drainage system consists of catch basins and 12” CPEP with an average slope of 3%. No evidence of flooding or erosion problems was observed. Component 2B ~ Infiltration Pond (80’ – 490’) Runoff outlets into a pre-settling wetpond followed by an infiltration pond located in the northern portion of the Cottages West site. No evidence of flooding or erosion problems was observed. Directly north of the pond, an apartment complex was constructed in the mid 1980’s under King County jurisdiction under the name of The Height on West Campus. At the time King County allowed the developer to build a retaining wall along their southern property line of The Height on West Campus. This retaining wall blocked the natural discharge point and created a manmade closed depression. If runoff were to leave the pond, approximately 10 feet of water would need to be in place for any runoff to discharge from the site. Note: The infiltration pond in TDA 2 is designed to fully infiltrate runoff up to the 100-year storm event. Therefore, the following discussion applies only to overflows, which exceed the 100-year event and are beyond the scope design. Component 2C ~ Channeled Flow (490’ – 630’) Runoff from the pond would flow north onto an internal road for The Height on West Campus apartments. This runoff would be routed north over asphalt and along the flowline of the internal road, which has an average slope of 2%. No problems were observed. Component 2D ~ Pipe Flow (630’ – 1,440’) Runoff is collected by the drainage system of The Height on West Campus and routed east, towards the 1st Avenue South sag location. This drainage system consists of catch basins and 12” pipes with an average slope of 5%. No problems were observed. 21 Village Green of Federal Way DCI 98480.6 Component E ~ Culvert (1,440’ – 1,480’) TDA 2 overflows would recombine with TDA 1 runoff at this drainage component. Task 5 – Mitigation of Existing or Potential Problems It is recommended that trash and debris, such as shopping carts, be removed from the existing Village Green stormwater facilities (Component 1B) and from the inlet of the 1st Avenue S cross culvert (Component E). This debris could cause problems if washed into the pipes and flow control devices or could cause plugging or improper operation of the pond. It is also recommended that vegetation be trimmed and mowed within a 5-foot perimeter of the various pond inlet and outlet pipes to reduce the chance of plugging and also to allow for periodic inspection and cleaning. Mitigation for the dissolved oxygen problem identified in the resource review applies only to wetvaults, which are not included in this project. Mitigation for the temperature problem identified in the resource review requires shading of wetpond. The wetpond for this project is an existing facility, which is completely surrounded by trees and with trees growing in the divider berm. Furthermore, no expansion of the wetpool portion of the pond is proposed. Any expansion of the detention (live storage) portion of the pond should include replacement of trees to provide shading. Note that the dissolved oxygen and temperature problems are not applicable to TDA 2, where runoff is fully infiltrated. 22 Job No. 98480.6Drawn: HMDScale: 1"=300' Figure 3.1 - OFFSITE ANALYSIS MAP Civil Engineering · Surveying · Land Planning D U N C A N S O N C O M P A N Y, I N C. 145 SW 155th Street, Suite 102 Seattle, Washington 98166 Phone 206.244.4141 Fax 206.244.4455 23 Figure 3.2 – Critical Areas Map Scale: Shown Above Drawn: HMD Job No: 98480.6 24 OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2 Basin: Hylebos Creek Basin Subbasin Name: TDA 1Subbasin Number: Symbol Drainage Component Type, Name, and Size Drainage Component Description Slope Distance from site discharge Existing Problems Potential Problems Observations of field inspector, resource reviewer, or resident See map. Type: sheet flow, swale, stream, channel, pipe, pond. Size: diameter, surface area. Drainage basin, vegetation, cover, depth, type of sensitive area, volume. % ¼ ml = 1,320 ft. Constrictions, under capacity, ponding, overtopping, flooding, habitat or organism destruction, scouring, bank sloughing, sedimentation, incision, other erosion.Tributary area, likelihood of problem, overflow pathways, potential impacts. 1A Pipe Flow 8” – 18” Pipe Varies <10%0’ – 880’ None None None 1B Combined Detention/Wetpond & Bioswale ±0% 880’ – 1,380’ Trash None w/maint. No flooding or erosion evidence. Trash & debris removal & brush trimming = normal maint.1C Pipe Flow 18” Pipe Varies 1,380’ – 1,825’ None NoneNone E Culvert 48” CMP ±2% 1,825’ – 1,865’ Trash None w/maint.Shopping carts/debris could cause blockage.F Sheet Flow Heavily vegetated ±2 1,865’+ None None Flows disperse beyond outlet. 25 OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2 Basin: Hylebos Creek Basin Subbasin Name: TDA 2Subbasin Number: Symbol Drainage Component Type, Name, and Size Drainage Component Description Slope Distance from site discharge Existing Problems Potential Problems Observations of field inspector, resource reviewer, or resident See map. Type: sheet flow, swale, stream, channel, pipe, pond. Size: diameter, surface area. Drainage basin, vegetation, cover, depth, type of sensitive area, volume. % ¼ ml = 1,320 ft. Constrictions, under capacity, ponding, overtopping, flooding, habitat or organism destruction, scouring, bank sloughing, sedimentation, incision, other erosion.Tributary area, likelihood of problem, overflow pathways, potential impacts. 2A Pipe Flow 12” CPEP tightline±3% 0’ – 80’ None None None 2B Pond Presettling/ Wetpond & Infiltration Pond±0% 80’ – 490’ None None None 2C Channeled Flow Over asphalt ±2% 490’ – 630’ None NoneNone2D Pipe Flow 12” CPEP tightline±5% 630’ – 1,440’ None None Flows east under apartment complex road. See TDA1 for Components E and F 26 Village Green of Federal Way DCI 98480.6 Section 4 Flow Control, Low Impact Development (LID) and Water Quality Facility Analysis and Design 27 Village Green of Federal Way DCI 98480.6 Section 4 – Flow Control, LID, & Water Quality Facility Analysis & Design TDA 1 Part A – Existing Site Hydrology Stormwater from the TDA 1 site is and will be collected in catch basins and routed through an existing detention/wet pond located in the northeastern corner of the Village Green site – see Figure 1.3.1 – TDA 1 Basin Map. While Village Green Phase I is not part of the current proposal, it was necessary to model the hydrology of that existing development since it also contributes to the same detention pond that the current project TDA 1 will use. The Village Green Phase I impervious and pervious areas will remain; are not being redeveloped; are mitigated by an existing facility; and are not target impervious surfaces. TDA 1 is 4.37 acres. The small paved loop driveway existed prior to 2001 and is not considered a target surface; and was therefore modeled as impervious. The remainder of TDA 1 is target surface and is modeled as C, Forest. The combined existing site hydrology of the existing Village Green Phase I and the current project TDA 1 is summarized as follows: 28 Village Green of Federal Way DCI 98480.6 Part B – Developed Site Hydrology See Figures Figure 1.3.1 – TDA 1 Basin Map. Site improvements for TDA 1 will include sewer and water utility services, storm drain conveyance piping, dry utilities, roads, sidewalks and five buildings. The fully developed site conditions will have approximately 6.39 acres of impervious surface including the existing Phase I areas. The remainder of the site was modeled as C, Lawn. The various cover types occur in the following proportions: TDA 2 Stormwater from the TDA 2 is collected in catch basins and routed through an existing presettling/wet pond to an infiltration pond located in the northwestern corner of the Cottages West site – see Figure 1.3.2 – TDA 2 Basin Map. Complete water quality and infiltration analysis and sizing is contained in the TIR for the Plat of Tuscany (FW 01-103235-00-EN). The existing infiltration pond was design to fully infiltrate all runoff, thus achieving the Conservation Flow Control standard. Also, since TDA 2 is served by an infiltration pond, On-Site Stormwater BMPs are not required in this TDA. Soil treatment, preceded by the presettling pond provide the Enhanced Basic Water Quality Standard. Part C – Performance Standards The site is subject to Conservation Flow Control and Enhanced Basic Water Quality standards. 29 Village Green of Federal Way DCI 98480.6 Part D – TDA 1 Flow Control System The existing detention pond was designed to meet a peak flow matching standard, dating back to circa 1990 requirements. The current Conservation Flow Control standard is more restrictive. Based on as-built information the existing pond provides approximately 90,000 CF of storage volume. A WWHM analysis was run to determine and approximate pond volume to meet the current Conservation Flow Control Standard, matching forested conditions for all new target surfaces and existing conditions for existing development draining to the same pond. It is estimated that the pond will need to be expanded to approximately 147,000 CF (3.38 ac-ft) to meet current standards. This can be achieved by expanding the pond to the west and south and increasing the berm height by approximately 0.8 feet. The flow control structure will also need to be modified. A conceptual pond configuration is presented below. A WWHM report is included in Appendix A. 30 Village Green of Federal Way DCI 98480.6 BMP Selection Full Dispersal is not feasible on this site due to lack of available flow paths. Full Infiltration is also not likely feasible due to soil type. Limited room is available making Bioretention likely infeasible. BMP requirements are expected to be achieved with areas of Permeable Pavement in light traffic areas, with Limited Infiltration where soil conditions are favorable and Basic Dispersal can be employed around the site where minimum flow paths are available. Potential BMPs are shown on the preliminary drainage plan. Final selection and location of On-Site Stormwater BMPs will be done at the building permit stage. No credit has been taken for BMPs in the above detention sizing, although BMPs will likely reduce the required size of the detention pond. Part E – TDA 1 Water Quality System The existing wetpond followed by a biofiltration swale does not meet the current Enhanced Basic Water Quality Standard. In order to meet this standard for this Phase of the project, Filterra planter boxes are proposed to treat runoff from new/replaced pollution generating surfaces (PGIS and PGPS). Filterra have WSDOE GULD approval to provide Enhance treatment. Filterra units can be located adjacent to the drive aisles and parking bays. Where required due to grade constraints, runoff may be piped to remote Filterra planters to allow for gravity flow. Final placement and number of Filterra units will be determined at building permit stage when the final grading plan is developed. The sizing and number of Filterra units will be based on Ecology’s GULD approved loading rates. Roof material is planned to be composition, which is excluded from PGIS. A non- leachable covenant can accompany the future building permits. It is not expected that the wetpool volume will need to be expanded as the sizing methodology of these facilities has not changed over the years. 31 Village Green of Federal Way DCI 98480.6 Section 5 Conveyance System Analysis and Design 32 Village Green of Federal Way DCI 98480.6 Section 5 – Conveyance System Analysis and Design This section will be completed at the final engineering stage. 33 Village Green of Federal Way DCI 98480.6 Section 6 Special Reports and Studies 34 Village Green of Federal Way DCI 98480.6 Section 6 – Special Reports and Studies A current geotechnical report (ZipperGeo 2018) has been prepared and is included in the following pages. 35 GEOTECHNICAL ENGINEERING REPORT VILLAGE GREEN RETIREMENT CAMPUS 35419 1st AVENUE S FEDERAL WAY, WASHINGTON Project No. 1969.01 March 19, 2018 Prepared for: RJ Development Prepared by: 19019 36th Avenue W., Suite E Lynnwood, WA 98036 Approximate Current Phase of Construction 36 Project No. 1969.01 March 19, 2018 RJ Development 401 Central Street SE Olympia, WA 98501 Attn: Mr. Austin Groves Subject: Geotechnical Engineering Report Village Green Retirement Campus 35419 1st Avenue S Federal Way, Washington Dear Mr. Groves, In accordance with your request and written authorization, Zipper Geo Associates, LLC (ZGA) has completed the subsurface exploration and geotechnical engineering evaluation for the current phase of the proposed Village Green Retirement Campus. This report presents the results of the subsurface exploration and document review, as well as our geotechnical engineering recommendations for the project. Our services were completed in general accordance with our Proposal for Geotechnical Engineering Services (Proposal No. P18103) dated February 6, 2018. Written authorization to proceed on our proposed scope of services was also provided by RJ Development on February 6, 2018. We appreciate the opportunity to be of service to you on this project. If you have any questions concerning this report, or if we may be of further service, please contact us. Sincerely, Zipper Geo Associates, LLC James P. Georgis, L.E.G. Ryan M. Scheffler, P.E. Principal Senior Geotechnical Engineer 37 TABLE OF CONTENTS Page INTRODUCTION ........................................................................................................................................... 1 SITE AND PROJECT DESCRIPTION .......................................................................................................... 1 SUBSURFACE CONDITIONS...................................................................................................................... 2 Mapped Geology ............................................................................................................................................. 2 Soil Conditions ................................................................................................................................................. 2 Groundwater Conditions ................................................................................................................................. 2 Laboratory Testing .......................................................................................................................................... 3 CONCLUSIONS AND RECOMMENDATIONS ............................................................................................ 3 General Considerations ................................................................................................................................... 3 Site Preparation ............................................................................................................................................... 3 Structural Fill Materials and Preparation ........................................................................................................ 4 Seismic Design Considerations ........................................................................................................................ 7 Shallow Foundation Recommendations .......................................................................................................... 8 On-Grade Concrete Slabs ................................................................................................................................ 8 Lateral Earth Pressures .................................................................................................................................... 8 Stormwater Management ............................................................................................................................... 9 CLOSURE ................................................................................................................................................... 10 Figure 1 – Site and Exploration Plan APPENDICES Appendix A – Subsurface Exploration Procedures and Logs Appendix B – Laboratory Testing Procedures and Results Appendix C – Excerpts from Earth Consultants, Inc. Reports Cover Page Photo Credit: Google Earth Pro, 2017 Aerial Photo 38 GEOTECHNICAL ENGINEERING REPORT VILLAGE GREEN RETIREMENT CAMPUS FEDERAL WAY, WASHINGTON Project No. 1969.01 March 19, 2018 INTRODUCTION This report documents the surface and subsurface conditions encountered at the project site and our geotechnical engineering recommendations for the current proposed phase of the Village Green Retirement Campus in Federal Way, Washington. The project description, site conditions, and our geotechnical conclusions and design recommendations are presented in the text of this report. Supporting data including detailed exploration logs and field exploration procedures, results of laboratory testing, and other supporting information are presented as appendices. Our geotechnical engineering scope of services for the project included a review of published geologic maps and previously completed geotechnical reports for the site by Earth Consultants, Inc. (ECI), site reconnaissance, subsurface evaluation, laboratory testing, geotechnical engineering analysis, and preparation of this report. The subsurface evaluation included advancement of six exploratory borings (designated B-1 through B-6) extending to depths between approximately 16½ to 26½ feet below the existing ground surface near the proposed building locations. ECI’s previous reports also include exploration logs for 2 borings and 23 test pits completed across the larger project site, including three test pits within the bounds of the current project phase. SITE AND PROJECT DESCRIPTION The project is located on a roughly 4.9-acre parcel north of SW 356th Street and west of 2nd Avenue SW in Federal Way, Washington. In addition to the subject parcel, two additional parcels to the north and east comprise the Village Green Retirement Campus. Residences and community buildings with associated infrastructure were previously constructed on the adjacent eastern parcel during an initial development phase in 2002 or 2003 and an on the northern parcel some time between 2007 and 2009. Two new residential structures are currently under construction near the northeast corner of the subject parcel. We understand the project will consist of constructing four new residential structures, a small community building, and a larger multi-story memory care facility. The site generally grades down from southeast to northwest. Based on the site grades and layout of existing buildings, we expect the new buildings will primarily consist of 1 to 2 stories with daylight basements below. Access roads (4th Place SW, SW 353rd Place, and 354th Place) and utilities for the current development phase were previously constructed, so limited paving and minor utility connections are anticipated. We understand the stormwater detention and infiltration ponds located near the northwest corner of the campus were originally sized for the fully developed site and resizing or construction of new facilities is not currently anticipated. A groundwater monitoring program is currently in place within the existing infiltration pond and results will be presented after the data loggers have been removed upon conclusion of the wet season. 39 SUBSURFACE CONDITIONS Mapped Geology According to the U.S. Geological Survey Geologic Map of the poverty bay 7.5’ quadrangle, King and Pierce Counties, by Booth, D.B., Waldron, H.H., and Troost, K.G. (2004), the surficial geology including the area of the project site is mapped as recessional outwash deposits (Qvr) with glacial till (Qvt) deposits mapped nearby to the west. The recessional deposits are described as consisting of stratified sand and gravel with some areas of silty sand that were deposited by meltwater streams during glacial retreat. The glacial till deposits were transported, deposited, and overridden by glaciers and commonly consist of compact mixture of sand, silt, and gravel that is often referred to as “hardpan.” The soil conditions encountered in our borings generally matched the mapped deposits and we interpreted the upper, relatively coarse- grained material as recessional outwash with the siltier glacial till below. ECI’s reports did not label the upper material, but they described the soil below as glacial till. Soil Conditions The subsurface evaluation for this project included advancement of six borings (B-1 through B-6) completed throughout the area of the current phase. The borings were extended to depths ranging from about 16½ to 30½ feet below the existing ground surface and their approximate locations are shown on Figure 1, the Site and Exploration Plan. Soils were visually classified in general accordance with the Unified Soil Classification System. A descriptive log of the subsurface exploration and the procedures utilized in the subsurface exploration program are presented in Appendix A. A generalized description of soil conditions encountered in the borings is presented below. Please refer to the boring logs in Appendix A for a more detailed description of the conditions encountered at the exploration locations. Soil conditions observed in the borings generally consisted of about 4 to 6 inches of root mass, forest duff, and topsoil underlain by medium dense to very dense gravels and sands with a low to moderate silt content, interpreted as recessional outwash, to depths ranging from about 7 to 19 feet. Below the outwash, very dense silty sand with gravel, interpreted as glacial till, was encountered to the full exploration depths. The moisture content of the samples collected from the borings generally ranged from damp to moist. Three test pits advanced by ECI within the area of the current phase (TP-105 through TP-107) were excavated to depths of about 8 to 9 feet below the ground surface. The logs of these test pits, as well as ECI’s Boring & Test Pit Location Plan, are included in Appendix C. Within the test pits, ECI generally reported similar soil conditions to those noted above, though these test pits did not appear to extend into the underlying glacial till. Groundwater Conditions Groundwater was not encountered within the full depth of our borings during the time of drilling, nor was it reported by ECI within their explorations. Fluctuations in groundwater levels, and the development of 40 perched groundwater layers, will likely occur due to seasonal variations in the amount of rainfall, runoff and other factors not evident at the time the exploration was performed. Therefore, groundwater levels during construction or at other times in the life of the structure may be higher than indicated on the logs. The possibility of groundwater level fluctuations should be considered when developing the design and construction plans for the project. A groundwater monitoring program is currently in progress within the infiltration pond near the northwest corner of the site. Results of the monitoring program will be presented following conclusion of the wet season. Laboratory Testing Laboratory testing for soil moisture content, fines content, and grain-size distribution was completed on selected samples obtained from our borings. The results of the moisture content tests are presented on the boring logs in Appendix A while the results of the grain-size distribution tests are presented in Appendix B. In general, test results indicated the upper recessional outwash soils have a fines content (that portion passing the U.S. No. 200 sieve) on the order of about 5 to 13 percent, while the deeper glacial till has a fines content of about 32 to 35 percent. CONCLUSIONS AND RECOMMENDATIONS General Considerations Based on the subsurface conditions encountered and described in previous sections, in our opinion the proposed buildings can be supported on conventional shallow foundations bearing on at least medium dense native soil, contingent on proper design and construction practices and implementation of the recommendations presented in this report. Geotechnical engineering recommendations for shallow spread footings and other earthwork related phases of the project are presented below. The recommendations contained in this report are based upon the results of field and laboratory testing (which are presented in Appendices A and B), review of previews reports for the larger development by ECI (excerpts of which are presented in Appendix C), engineering analyses, and our current understanding of the proposed project. ASTM and Washington State Department of Transportation (WSDOT) specification codes cited herein respectively refer to the current manual published by the American Society for Testing & Materials and the 2016 edition of the Standard Specifications for Road, Bridge, and Municipal Construction (M41-10). Site Preparation Clearing and Stripping: Based on conditions observed in our borings we expect stripping depths on the order of about 4 to 8 inches in depth will be required to remove the upper forest duff and organic material from below areas of future pavements and structures. These materials are not suitable for reuse as structural fill. Greater depths will likely be required to remove root balls associated with the trees and brush covering much of the undeveloped portions of the site. 41 Subgrade Preparation: Once site preparation is complete, all areas that do not require over-excavation and are at design subgrade elevation or areas that will receive new structural fill should be compacted to a firm and unyielding condition. Depending on conditions encountered at the time of construction, some moisture conditioning of subgrade soils may be required to achieve a moisture content appropriate for compaction. The extent of moisture conditioning will likely be a function of when the site earthwork takes place. A suitable moisture content is generally within ±2 percent of the soils optimum moisture content. As noted above, laboratory tests indicate the upper recessional outwash sands and gravels encountered in our explorations have a fines content on the order of about 5 to 13 percent. These soils will be moderately sensitive to disturbance from construction activity and increased moisture. If exposed in excavations for daylight basements or deeper footings, the underlying glacial till soils will be highly moisture sensitive due to their relatively high fines content. If possible, we recommend that earthwork be completed during drier periods of the year when the soil moisture content can be controlled by aeration and drying. If earthwork or construction activities take place during extended periods of wet weather, or if the in situ moisture conditions are elevated above the optimum moisture content, the soils could become unstable or not be compactable. Construction activity should be monitored and should be limited to the extent feasible if the activity is causing subgrade disturbance. In the event the exposed subgrade becomes unstable, yielding, or unable to be compacted due to high moisture conditions, we recommend that the materials be removed to a sufficient depth in order to develop stable subgrade soils that can be compacted to the minimum recommended levels. The severity of construction problems will be dependent, in part, on the precautions that are taken by the contractor to protect the subgrade soils. If protecting stable subgrades becomes necessary, either inside or outside the building pads, we recommend using crushed rock or crushed recycled concrete. The thickness of the protective layer should be determined by the contractor at the time of construction based on the moisture condition of the soil, weather conditions, and the amount of anticipated traffic. Freezing Conditions: If earthwork takes place during freezing conditions, exposed subgrades should be allowed to thaw and then be compacted prior to placing subsequent lifts of structural fill. Alternatively, the frozen material could be stripped from the subgrade to expose unfrozen soil prior to placing subsequent lifts of fill or foundation components. The frozen soil should not be reused as structural fill until allowed to thaw and adjusted to the proper moisture content, which may not be possible during winter months. Structural Fill Materials and Preparation Structural fill includes any material placed below or adjacent to foundations, below concrete slabs, within utility trenches, or other areas to support settlement-sensitive site improvements. Prior to the placement of structural fill, all surfaces to receive fill should be prepared as previously recommended in the Site Preparation section of this report. 42 Reuse of Site Soils as Structural Fill: Field and laboratory test data indicate that the soils encountered on site below the topsoil and forest duff are suitable for reuse as general structural fill from a compositional standpoint provided the soil is placed and compacted in accordance with the compaction recommendations presented in this report. However, as noted above, the recessional outwash sand and gravel soil has a fines content on the order of about 5 to 13 percent and will be moderately sensitive to increases in moisture content. The underlying glacial till has a relatively high portion of fines and will be highly moisture sensitive. If site soils are planned for reuse, they should be protected from an increase in moisture content during periods of wet weather. At a minimum, we recommend stockpiles of excavated material to be used as structural fill on the site be covered with plastic sheeting if rain is in the forecast. We recommend that site soils used as structural fill have less than 4 percent organics by weight and have no woody debris greater than ½ inch in diameter. We recommend that all pieces of organic material greater than ½ inch in diameter be picked out of the fill before it is compacted. Any organic-rich soil derived from earthwork activities should be utilized in landscape areas or wasted from the site. Imported Structural Fill: Imported structural fill may be required if the on-site soils cannot be adequately compacted at the time of construction due to elevated moisture content, or other reasons. The appropriate type of imported structural fill will depend on weather conditions. During extended periods of dry weather, we recommend imported fill, at a minimum, meet the requirements of Common Borrow as specified in Section 9-03.14(3) of the 2016 Washington State Department of Transportation, Standard Specifications for Road, Bridge, and Municipal Construction (WSDOT Standard Specifications). During wet weather and/or wet site conditions, higher-quality structural fill might be required, as Common Borrow may contain sufficient fines to be moisture-sensitive. During wet conditions, we recommend that imported structural fill consist of a “clean”, free-draining pit-run sand and gravel. Such material should generally contain less than 5 percent fines, based on that soil fraction passing the U.S. No. 4 sieve, and not contain discrete particles greater than 3 inches in maximum dimension. Alternatively, Crushed Surfacing Base Course or Gravel Borrow conforming to Sections 9-03.9(3) and 9-03.14(1), respectively, of the WSDOT Standard Specifications could be used during wet weather. It should be noted that the placement of structural fill is, in many cases, weather-dependent. Delays due to inclement weather are common, even when using select granular fill. We recommend that site grading and earthwork be scheduled for the drier months, if possible. Moisture Content: The suitability of soil for use as structural fill will depend on the time of year, the moisture content of the soil, and the fines content of the soil. As the amount of fines increases, the soil becomes increasingly sensitive to small changes in moisture content. Soils containing more than about 5 percent fines (such as the deeper on-site glacial till soils) cannot be consistently compacted to the appropriate levels when the moisture content is more than approximately 2 percent above or below the optimum moisture content (per ASTM D 1557). Optimum moisture content is that moisture content which results in the greatest compacted dry density with a specified compactive effort. Fill Placement and Compaction: Structural fill should be placed in horizontal lifts not exceeding 10 inches in loose thickness. Thinner lifts may be necessary, depending on the size and weight of the compaction 43 equipment. Each lift of fill should be compacted to the minimum levels recommended in the table below based on the maximum laboratory dry density as determined by the ASTM D 1557 Modified Proctor Compaction Test. Structural fill placed in municipal rights-of-way should be placed and compacted in accordance with the jurisdiction codes and standards. We recommend that a geotechnical engineer be present during grading so that an adequate number of density tests may be conducted as structural fill placement occurs. In this way, the adequacy of the earthwork may be evaluated as it proceeds. Recommended Soil Compaction Levels Location Minimum Percent Compaction* Stripped native subgrade soils, prior to fill placement (upper 12 inches) 95 All fill below building floor slabs and foundations 95 Upper 2 feet of fill below pavements 95 Pavement fill below two feet 92 Utility trench backfill 95 Landscape Areas 90 * ASTM D 1557 Modified Proctor Maximum Dry Density Temporary and Permanent Slopes: Temporary excavation slope stability is a function of many factors, including: • The presence and abundance of groundwater; • The type and density of the various soil strata; • The depth of cut; • Surcharge loadings adjacent to the excavation; and • The length of time the excavation remains open. It is exceedingly difficult under the variable circumstances to pre-establish a safe and “maintenance-free” temporary cut slope angle. Therefore, it should be the responsibility of the contractor to maintain safe temporary slope configurations since the contractor is continuously at the job site, able to observe the nature and condition of the cut slopes, and able to monitor the subsurface materials and groundwater conditions encountered. Unsupported vertical slopes or cuts deeper than 4 feet are not recommended if worker access is necessary. The cuts should be adequately sloped, shored, or supported to prevent injury to personnel from local sloughing and spalling. The excavation should conform to applicable Federal, State, and Local regulations. We recommend permanent fill placed on slopes steeper than about 5H:1V (Horizontal:Vertical) be keyed and benched into soils comprising the underlying slope. We recommend that the base downslope key be cut into undisturbed native soil and be at least 5 feet wide and 2 feet deep. The hillside benches cut into the native soil should be at least 3 feet in width. The intent of the benches is to provide a level surface onto which new fill can be placed and compacted. The face of the embankment should be compacted to 44 the same relative compaction as the body of the fill. This may be accomplished by over-building the embankment and cutting back to the compacted core. We recommend that all permanent cut or fill slopes constructed in native soils be designed at a 2½H:1V (Horizontal:Vertical) inclination or flatter. All permanent cut and fill slopes should be adequately protected from erosion both temporarily and permanently. Seismic Design Considerations Seismic Setting: Based on our review of the Washington Interactive Geologic Map available online (https://fortress.wa.gov/dnr/protectiongis/geology/), the project site lies within the Tacoma Fault Zone. The nearest mapped fault trace, however, is located approximately 1 mile to the northeast. According the USGS, the fault age is less than 15,000 years, has been mapped with east striking features, and is in the slip rate category of between 0.2 and 1.0 mm/year. Based on the information described above, we estimate that the risk associated with fault surface rupture at the site is low. IBC Seismic Design Parameters: Values provided below are based upon data from the 2012/2015 International Building Code. The following table summarizes our recommended seismic design criteria. Our recommendation to use Seismic Site Class D is based on the subsurface conditions encountered, deep subsurface conditions presented on geologic maps that include the project site, and our familiarity of the geologic conditions in the area. IBC Seismic Design Criteria Parameter Value 2012/2015 International Building Code Site Classification Site Class D Site Latitude/Longitude 47.2839/-122.3379 Mean Peak Ground Acceleration, PGAM 0.500g Spectral Short-Period Acceleration, Ss 1.285g (Site Class B) Spectral 1-Second Acceleration, S1 0.495g (Site Class B) Site Coefficient for a Short Period, Fa 1.000 Site Coefficient for a 1-Second Period, Fv 1.505 Spectral Acceleration for a 0.2-Second Period, SMS 1.285g (Site Class D) Spectral Acceleration for a 1-Second Period, SM1 0.745g (Site Class D) Design Short-Period Spectral Acceleration, SDS 0.857g (Site Class D) Design 1-Second Spectral Acceleration, SD1 0.497g (Site Class D) The site soils are not considered to be prone to liquefaction due to their relative density and the absence of groundwater observations within the full depth of our explorations. The potential for seismic related settlement is considered low and foundation bearing capacity failure is considered unlikely during a design-level earthquake. 45 Shallow Foundation Recommendations Allowable Bearing Pressure: In order to limit settlement to less than 1 inch total and ¾ inch over 40 feet differential, we recommend that continuous and column footings bearing on at least medium dense outwash soil or structural fill placed in accordance with the recommendations in this report and compacted to at least 95 percent of the modified Proctor maximum dry density per ASTM D 1557 be designed using a maximum allowable bearing capacity of 3,000 psf. A one-third increase of the bearing pressure may be used for short-term dynamic loads such as wind and seismic forces. Shallow Foundation Depth and Width: For frost protection, we recommend the bottom of all exterior footings bear at least 18 inches below the lowest adjacent outside grade, whereas the bottoms of interior footings should bear at least 12 inches below the surrounding slab surface level. We recommend that all continuous wall and isolated column footings be at least 12 and 24 inches wide, respectively. Lateral Resistance: We recommend using allowable base friction and passive earth resistance values 0.40 and 350 pcf equivalent fluid pressure, respectively. We recommend that passive resistance be neglected in the upper 18 inches of embedment. On-Grade Concrete Slabs Subgrade Preparation: After removal of trees, forest duff, organic material, and other items noted in the Site Preparation section of this report, we recommend at least the upper 12 inches of material below the slab base be scarified and recompacted to a firm and unyielding condition and to a minimum of 95 percent of the modified Proctor maximum dry density per ASTM D 1557. Slab Base: To provide a uniform slab bearing surface, capillary break, and even working surface, we recommend the on-grade slabs be underlain by a 6-inch thick layer of compacted crushed rock meeting the requirements of Crushed Surfacing Top Course as specified in Section 9-03.9(3) of the WSDOT Standard Specifications with the modification that a maximum of 7.5 percent of the material passes the U.S. No 200 sieve. Vapor Barrier: From a geotechnical perspective, a vapor barrier is not considered necessary beneath the slab on grade floor unless moisture sensitive floor coverings and/or adhesives are used. If a vapor barrier is used, we recommend using a 15-mil, puncture-resistant proprietary product such as Stego Wrap, or an approved equivalent that is classified as a Class A vapor retarder in accordance with ASTM E 1745. Overlap lengths and the appropriate tape used to seal the laps should be in accordance the vapor retarder manufacturer’s recommendations. To avoid puncturing of the vapor barrier, a thin sand layer placed over the crushed gravel is recommended. When conditions warrant the use of a vapor retarder, the slab designer and slab contractor should refer to ACI 302 and ACI 360 for procedures and cautions regarding the use and placement of a vapor retarder/barrier. Lateral Earth Pressures The lateral soil pressures acting on backfilled retaining walls will depend on the nature and density of the soil behind the wall, and the ability of the wall to yield in response to the earth loads. Yielding walls (i.e. 46 walls that are free to translate or rotate) that are able to displace laterally at least 0.001H, where H is the height of the wall, may be designed for active earth pressures. Non-yielding walls (i.e. walls that are not free to translate or rotate) should be designed for at-rest earth pressures. Non-yielding walls include walls that are braced to another wall or structure, and wall corners. Assuming that walls are backfilled and drained as described in the following paragraphs, we recommend that yielding walls supporting horizontal backfill be designed using an equivalent fluid density of 35 pcf (active earth pressure). Non-yielding walls should be designed using an equivalent fluid density of 50 pcf (at-rest earth pressure). Surcharge pressures due to sloping backfill, adjacent footings, vehicles, construction equipment, etc. must be added to these lateral earth pressure values. For traffic loads, we recommend using an equivalent two-foot soil surcharge of about 250 psf. For yielding and non-yielding walls with level backfill conditions, we recommend that a uniformly distributed seismic pressure of 7H psf for the active case and 12H psf for the at-rest case, where H is the height of the wall, be applied to the walls. The above equivalent fluid pressures are based on the assumption of no buildup of hydrostatic pressure behind the wall. If groundwater is allowed to saturate the backfill soils, hydrostatic pressures will act against a retaining wall; however, if the recommended drainage system is included with each retaining wall, we do not expect that hydrostatic pressures will develop. Stormwater Management As a part of previous construction phases, a stormwater detention pond and an infiltration pond were constructed near the northwest corner of the campus. We understand the ponds were sized to accommodate the full campus buildout and will be used to treat and infiltrate stormwater runoff from the current proposed phase. In order to aid in evaluation of the current functionality of the infiltration pond, we excavated a small pit using hand tools near the center of the pond and installed a groundwater level data logger within a vertical, slotted PVC pipe. The data logger will be retrieved upon conclusion of the wet season and hourly water level readings from the date of installation to the date of retrieval will be downloaded and processed. A letter addendum to this report will be submitted following retrieval of the data logger that includes a summary of the water levels observed in the infiltration pond, subsurface conditions encountered in our hand excavation, and results of cation exchange capacity and organic content tests performed on shallow soils obtained from our hand excavation. 47 CLOSURE The analysis and recommendations presented in this report are based, in part, on the explorations completed for this study and review of previously prepared reports described in the text. The number, location, and depth of the explorations for the current phase of the project were completed within the constraints of budget and site access so as to yield the information to formulate our recommendations. Project plans were in the preliminary stage at the time this report was prepared. We therefore recommend Zipper Geo Associates, LLC be provided an opportunity to review the final plans and specifications when they become available in order to assess that the recommendations and design considerations presented in this report have been properly interpreted and implemented into the project design. The performance of shallow foundations and slabs on grade depend greatly on proper site preparation and construction procedures. We recommend that Zipper Geo Associates, LLC be retained to provide geotechnical engineering services during the site preparation and foundation construction phases of the project. If variations in subsurface conditions are observed at that time, a qualified geotechnical engineer could provide additional geotechnical recommendations to the contractor and design team in a timely manner as the project construction progresses. This report has been prepared for the exclusive use of RJ Development, and their agents, for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Zipper Geo Associates, LLC reviews the changes and either verifies or modifies the conclusions of this report in writing. 48 B-2B-1B-4B-3B-5B-6TP-105TP-106TP-107FIGUREJob No.Zipper Geo Associates, LLC19019 36th Ave. W.,Suite ELynnwood, WASHT. of11SITE AND EXPLORATION PLAN1969.01DATE: MARCH 20181VILLAGE GREEN RETIREMENT CAMPUS35419 1ST AVENUE SOUTHFEDERAL WAY, WASHINGTONSCALE IN FEET0 30 LEGENDZGA BORING NUMBER ANDAPPROXIMATE LOCATION (2018)REFERENCE: MARKETING SITE PLAN BY RJ DEVELOPMENT DATED OCTOBER 31, 2017.5050250APPROXIMATE SCALE IN FEETTP-106B-6EARTH CONSULTANTS, INC. TESTPIT NUMBER AND APPROXIMATELOCATION (2000)49 APPENDIX A SUBSURFACE EXPLORATION PROCEDURES AND LOGS 50 APPENDIX A SUBSURFACE EXPLORATION PROCEDURES AND LOGS Field Exploration Description Our field exploration for this project included advancing six borings across the proposed current phase of the project on February 18, 2018. The approximate locations of the explorations are presented on Figure 1, the Site and Exploration Plan. Exploration locations were determined in the field based on hand measurements from existing site features. As such, the exploration locations should be considered accurate only to the degree implied by the measurement method. Descriptive logs of the borings are enclosed in this appendix. A current topographic survey of the site was not available at the time of this report. Therefor, ground surface elevations of the explorations were not determined. The borings were advanced using a track-mounted drill rig operated by an independent drilling company (Holocene Drilling, Inc.) working under subcontract to ZGA. The borings were advanced using hollow- stem auger drilling methods. An engineer from our firm continuously observed the borings, logged the subsurface conditions encountered, and obtained representative soil samples. All samples were stored in moisture-tight containers and transported to our laboratory for further evaluation and testing. Samples were obtained by means of the Standard Penetration Test at 2.5- to 5-foot intervals throughout the drilling operation. The Standard Penetration Test (ASTM D 1586) procedure consists of driving a standard 2-inch outside diameter steel split spoon sampler 18 inches into the soil with a 140-pound hammer free falling 30 inches. The number of blows required to drive the sampler through each 6-inch interval is recorded, and the total number of blows struck during the final 12 inches is recorded as the Standard Penetration Resistance, or “blow count” (N value). If a total of 50 blows is struck within any 6-inch interval, the driving is stopped and the blow count is recorded as 50 blows for the actual penetration distance. The resulting Standard Penetration Resistance values indicate the relative density of granular soils and the relative consistency of cohesive soils. The enclosed boring logs describe the vertical sequence of soils and materials encountered in the borings, based primarily upon our field classifications. Where a soil contact was observed to be gradational, our log indicates the average contact depth. Where a soil type changed between sample intervals, we inferred the contact depth. Our logs also graphically indicate the blow count, sample type, sample number, and approximate depth of each soil sample obtained from the borings. If groundwater was encountered, the approximate groundwater depth, and date of observation, are depicted on the logs. 51 Drilling Company:Bore Hole Dia.: Top Elevation:Drilling Method:Hammer Type: Drill Rig:Logged by: Standard Penetration Test Hammer Weight and Drop: SAMPLE LEGEND GROUNDWATER LEGEND % Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Liquid Limit Grout/Concrete Screened Casing TESTING KEY Blank Casing GSA = Grain Size Analysis 200W = 200 Wash Analysis Date:Project No.: Consol. = Consolidation Test Att. = Atterberg Limits Groundwater level at time of drilling (ATD) or on date of measurement. Natural Water Content March 2018 B-1 B-1 1969.01Blow CountsVillage Green Retirement Campus 35419 1st Avenue South Zipper Geo Associates 19019 36th Ave. W, Suite E Lynnwood, WA Federal Way, Washington Page 1 of 2 BORING LOG:TestingPlastic Limit Boring Location:Sample Number SAMPLES RecoveryDepth (ft)SOIL DESCRIPTION Date Drilled: The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information.Ground WaterPENETRATION RESISTANCE (blows/foot) 0 20 40 60 6" 7" 6" 0" 6" 13" S-1 S-2 S-3 S-4 S-5 S-6 0 5 10 15 20 25 See Figure 1, Site and Exploration Plan - 2/18/2018 Holocene Drilling Hollow Stem Auger D50 8 inches Auto 11/2/1219 31 31 56 50/4 50/6 MC SNM 6 inches of grass, organics, and forest duff Medium dense to dense, moist, tan, gravelly SAND, some silt (Recessional Outwash) Very dense, moist, gray-brown, silty SAND, with gravel (Glacial Till) 52 Drilling Company:Bore Hole Dia.: Top Elevation:Drilling Method:Hammer Type: Drill Rig:Logged by: Standard Penetration Test Hammer Weight and Drop: SAMPLE LEGEND GROUNDWATER LEGEND % Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Liquid Limit Grout/Concrete Screened Casing TESTING KEY Blank Casing GSA = Grain Size Analysis 200W = 200 Wash Analysis Date:Project No.: Consol. = Consolidation Test Att. = Atterberg Limits Groundwater level at time of drilling (ATD) or on date of measurement. Federal Way, Washington 1969.01 Zipper Geo Associates 19019 36th Ave. W, Suite E Lynnwood, WA BORING LOG:B-1 Page 2 of 2 March 2018 35419 1st Avenue South The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Plastic Limit Natural Water Content Village Green Retirement Campus Boring Location: B-1 Date Drilled:Depth (ft)SOIL DESCRIPTION Sample Number SAMPLES RecoveryGround WaterPENETRATION RESISTANCE (blows/foot)Blow CountsTesting12"S-7 0 20 40 60 25 30 35 40 45 50 See Figure 1, Site and Exploration Plan - 2/18/2018 Holocene Drilling Hollow Stem Auger D50 8 inches Auto 11/2/1250/3 SNM Boring terminated at approximately 26 1/2 feet. Groundwater not observed while drilling. 53 Drilling Company:Bore Hole Dia.: Top Elevation:Drilling Method:Hammer Type: Drill Rig:Logged by: Standard Penetration Test Hammer Weight and Drop: SAMPLE LEGEND GROUNDWATER LEGEND % Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Liquid Limit Grout/Concrete Screened Casing TESTING KEY Blank Casing GSA = Grain Size Analysis 200W = 200 Wash Analysis Date:Project No.: Consol. = Consolidation Test Att. = Atterberg Limits Boring Location:Sample Number SAMPLES RecoveryDepth (ft)SOIL DESCRIPTION Date Drilled: The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information.Ground WaterPENETRATION RESISTANCE (blows/foot) B-2 B-2 1969.01Blow CountsVillage Green Retirement Campus 35419 1st Avenue South Zipper Geo Associates 19019 36th Ave. W, Suite E Lynnwood, WA Federal Way, Washington Page 1 of 2 BORING LOG:TestingPlastic Limit Groundwater level at time of drilling (ATD) or on date of measurement. Natural Water Content March 2018 0 20 40 60 0" 0" 0" 5" 5" 13" S-1 S-2 S-3 S-4 S-5 S-6 0 5 10 15 20 25 See Figure 1, Site and Exploration Plan - 2/18/2018 Holocene Drilling Hollow Stem Auger D50 8 inches Auto 11/2/1250/6 22 19 19 19 50 MC SNM 2 inches crushed gravel surfacing Medium dense, moist, brown, sandy GRAVEL, some silt (Recessional Outwash) Blowcount overstated on rock Hard, wet, brown, sandy SILT, with gravel Very dense, moist, gray-brown, silty SAND, with gravel (Glacial Till) 54 Drilling Company:Bore Hole Dia.: Top Elevation:Drilling Method:Hammer Type: Drill Rig:Logged by: Standard Penetration Test Hammer Weight and Drop: SAMPLE LEGEND GROUNDWATER LEGEND % Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Liquid Limit Grout/Concrete Screened Casing TESTING KEY Blank Casing GSA = Grain Size Analysis 200W = 200 Wash Analysis Date:Project No.: Consol. = Consolidation Test Att. = Atterberg Limits Boring Location: B-2 Date Drilled:Depth (ft)SOIL DESCRIPTION Sample Number SAMPLES RecoveryGround WaterPENETRATION RESISTANCE (blows/foot)Blow CountsTesting35419 1st Avenue South The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Plastic Limit Natural Water Content Village Green Retirement Campus Groundwater level at time of drilling (ATD) or on date of measurement. Federal Way, Washington 1969.01 Zipper Geo Associates 19019 36th Ave. W, Suite E Lynnwood, WA BORING LOG:B-2 Page 2 of 2 March 2018 1"S-7 0 20 40 60 25 30 35 40 45 50 See Figure 1, Site and Exploration Plan - 2/18/2018 Holocene Drilling Hollow Stem Auger D50 8 inches Auto 11/2/1250/3 SNM Boring terminated at approximately 25 1/4 feet. Groundwater not observed while drilling. 55 Drilling Company:Bore Hole Dia.: Top Elevation:Drilling Method:Hammer Type: Drill Rig:Logged by: Standard Penetration Test Hammer Weight and Drop: SAMPLE LEGEND GROUNDWATER LEGEND % Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Liquid Limit Grout/Concrete Screened Casing TESTING KEY Blank Casing GSA = Grain Size Analysis 200W = 200 Wash Analysis Date:Project No.: Consol. = Consolidation Test Att. = Atterberg Limits Boring Location:Sample Number SAMPLES RecoveryDepth (ft)SOIL DESCRIPTION Date Drilled: The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information.Ground WaterPENETRATION RESISTANCE (blows/foot) B-3 B-3 1969.01Blow CountsVillage Green Retirement Campus 35419 1st Avenue South Zipper Geo Associates 19019 36th Ave. W, Suite E Lynnwood, WA Federal Way, Washington Page 1 of 2 BORING LOG:TestingPlastic Limit Groundwater level at time of drilling (ATD) or on date of measurement. Natural Water Content March 2018 0 20 40 60 10" 14" 13" 18" 18" 13" S-1 S-2 S-3 S-4 S-5 S-6 0 5 10 15 20 25 See Figure 1, Site and Exploration Plan - 2/18/2018 Holocene Drilling Hollow Stem Auger D50 8 inches Auto 11/2/1250/6 50/6 50/6 77 50/6 50/6 GSA MC SNM 4 to 6 inches of grass, organics, and forest duff Very dense, moist, tan, sandy GRAVEL, some silt (Recessional Outwash) Very dense, moist, gray-brown, silty SAND, with gravel (Glacial Till) 56 Drilling Company:Bore Hole Dia.: Top Elevation:Drilling Method:Hammer Type: Drill Rig:Logged by: Standard Penetration Test Hammer Weight and Drop: SAMPLE LEGEND GROUNDWATER LEGEND % Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Liquid Limit Grout/Concrete Screened Casing TESTING KEY Blank Casing GSA = Grain Size Analysis 200W = 200 Wash Analysis Date:Project No.: Consol. = Consolidation Test Att. = Atterberg Limits Boring Location: B-3 Date Drilled:Depth (ft)SOIL DESCRIPTION Sample Number SAMPLES RecoveryGround WaterPENETRATION RESISTANCE (blows/foot)Blow CountsTesting35419 1st Avenue South The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Plastic Limit Natural Water Content Village Green Retirement Campus Groundwater level at time of drilling (ATD) or on date of measurement. Federal Way, Washington 1969.01 Zipper Geo Associates 19019 36th Ave. W, Suite E Lynnwood, WA BORING LOG:B-3 Page 2 of 2 March 2018 15"S-7 0 20 40 60 25 30 35 40 45 50 See Figure 1, Site and Exploration Plan - 2/18/2018 Holocene Drilling Hollow Stem Auger D50 8 inches Auto 11/2/1250/6 SNM Boring terminated at approximately 26 feet. Groundwater not observed while drilling. 57 Drilling Company:Bore Hole Dia.: Top Elevation:Drilling Method:Hammer Type: Drill Rig:Logged by: Standard Penetration Test Hammer Weight and Drop: SAMPLE LEGEND GROUNDWATER LEGEND % Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Liquid Limit Grout/Concrete Screened Casing TESTING KEY Blank Casing GSA = Grain Size Analysis 200W = 200 Wash Analysis Date:Project No.: Consol. = Consolidation Test Att. = Atterberg Limits Groundwater level at time of drilling (ATD) or on date of measurement. Natural Water Content March 2018 B-4 B-4 1969.01Blow CountsVillage Green Retirement Campus 35419 1st Avenue South Zipper Geo Associates 19019 36th Ave. W, Suite E Lynnwood, WA Federal Way, Washington Page 1 of 1 BORING LOG:TestingPlastic Limit Boring Location:Sample Number SAMPLES RecoveryDepth (ft)SOIL DESCRIPTION Date Drilled: The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information.Ground WaterPENETRATION RESISTANCE (blows/foot) 0 20 40 60 0" 13" 18" 2" 18" S-1 S-2 S-3 S-4 S-5 0 5 10 15 20 25 See Figure 1, Site and Exploration Plan - 2/18/2018 Holocene Drilling Hollow Stem Auger D50 8 inches Auto 11/2/1250/3 40 41 59 65 MC MC SNM 4 to 6 inches of moss and forest duff Dense, moist, tan-brown, SAND, with gravel, some silt (Recessional Outwash) Very dense, moist, brown-gray, silty SAND, with gravel (Glacial Till) Boring terminated at approximately 16 1/2 feet. Groundwater not observed while drilling. Blowcount overstated on rock 58 Drilling Company:Bore Hole Dia.: Top Elevation:Drilling Method:Hammer Type: Drill Rig:Logged by: Standard Penetration Test Hammer Weight and Drop: SAMPLE LEGEND GROUNDWATER LEGEND % Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Liquid Limit Grout/Concrete Screened Casing TESTING KEY Blank Casing GSA = Grain Size Analysis 200W = 200 Wash Analysis Date:Project No.: Consol. = Consolidation Test Att. = Atterberg Limits Boring Location:Sample Number SAMPLES RecoveryDepth (ft)SOIL DESCRIPTION Date Drilled: The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information.Ground WaterPENETRATION RESISTANCE (blows/foot) B-5 B-5 1969.01Blow CountsVillage Green Retirement Campus 35419 1st Avenue South Zipper Geo Associates 19019 36th Ave. W, Suite E Lynnwood, WA Federal Way, Washington Page 1 of 2 BORING LOG:TestingPlastic Limit Groundwater level at time of drilling (ATD) or on date of measurement. Natural Water Content March 2018 0 20 40 60 8" 7" 8" 0" 8" 1" S-1 S-2 S-3 S-4 S-5 S-6 0 5 10 15 20 25 See Figure 1, Site and Exploration Plan - 2/18/2018 Holocene Drilling Hollow Stem Auger D50 8 inches Auto 11/2/1230 23 58 50/3 50/6 50/2 GSA MC SNM 6 to 8 inches of moss and forest duff Medium dense, moist, brown, sandy GRAVEL, with silt (Recessional Outwash) Grades to very dense Very dense, moist, gray-brown, silty SAND, some gravel (Glacial Till) Thin sandy SILT zone at 20 feet 59 Drilling Company:Bore Hole Dia.: Top Elevation:Drilling Method:Hammer Type: Drill Rig:Logged by: Standard Penetration Test Hammer Weight and Drop: SAMPLE LEGEND GROUNDWATER LEGEND % Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Liquid Limit Grout/Concrete Screened Casing TESTING KEY Blank Casing GSA = Grain Size Analysis 200W = 200 Wash Analysis Date:Project No.: Consol. = Consolidation Test Att. = Atterberg Limits Boring Location: B-5 Date Drilled:Depth (ft)SOIL DESCRIPTION Sample Number SAMPLES RecoveryGround WaterPENETRATION RESISTANCE (blows/foot)Blow CountsTesting35419 1st Avenue South The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Plastic Limit Natural Water Content Village Green Retirement Campus Groundwater level at time of drilling (ATD) or on date of measurement. Federal Way, Washington 1969.01 Zipper Geo Associates 19019 36th Ave. W, Suite E Lynnwood, WA BORING LOG:B-5 Page 2 of 2 March 2018 10"S-7 0 20 40 60 25 30 35 40 45 50 See Figure 1, Site and Exploration Plan - 2/18/2018 Holocene Drilling Hollow Stem Auger D50 8 inches Auto 11/2/1250/6 SNM Boring terminated at approximately 26 feet. Groundwater not observed while drilling. 60 Drilling Company:Bore Hole Dia.: Top Elevation:Drilling Method:Hammer Type: Drill Rig:Logged by: Standard Penetration Test Hammer Weight and Drop: SAMPLE LEGEND GROUNDWATER LEGEND % Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Liquid Limit Grout/Concrete Screened Casing TESTING KEY Blank Casing GSA = Grain Size Analysis 200W = 200 Wash Analysis Date:Project No.: Consol. = Consolidation Test Att. = Atterberg Limits Boring Location:Sample Number SAMPLES RecoveryDepth (ft)SOIL DESCRIPTION Date Drilled: The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information.Ground WaterPENETRATION RESISTANCE (blows/foot) B-6 B-6 1969.01Blow CountsVillage Green Retirement Campus 35419 1st Avenue South Zipper Geo Associates 19019 36th Ave. W, Suite E Lynnwood, WA Federal Way, Washington Page 1 of 2 BORING LOG:TestingPlastic Limit Groundwater level at time of drilling (ATD) or on date of measurement. Natural Water Content March 2018 0 20 40 60 4" 6" 18" 15" 18" 12" S-1 S-2 S-3 S-4 S-5 S-6 0 5 10 15 20 25 See Figure 1, Site and Exploration Plan - 2/18/2018 Holocene Drilling Hollow Stem Auger D50 8 inches Auto 11/2/1229 21 45 77 50/6 50/5 GSA 200W SNM 6 to 8 inches of moss and forest duff Medium dense, moist, brown, gravelly SAND, some silt (Recessional Outwash) Grades to dense, silty SAND, with gravel Very dense, moist, gray-brown, silty SAND, with to some gravel (Glacial Till) 61 Drilling Company:Bore Hole Dia.: Top Elevation:Drilling Method:Hammer Type: Drill Rig:Logged by: Standard Penetration Test Hammer Weight and Drop: SAMPLE LEGEND GROUNDWATER LEGEND % Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Liquid Limit Grout/Concrete Screened Casing TESTING KEY Blank Casing GSA = Grain Size Analysis 200W = 200 Wash Analysis Date:Project No.: Consol. = Consolidation Test Att. = Atterberg Limits Boring Location: B-6 Date Drilled:Depth (ft)SOIL DESCRIPTION Sample Number SAMPLES RecoveryGround WaterPENETRATION RESISTANCE (blows/foot)Blow CountsTesting35419 1st Avenue South The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Plastic Limit Natural Water Content Village Green Retirement Campus Groundwater level at time of drilling (ATD) or on date of measurement. Federal Way, Washington 1969.01 Zipper Geo Associates 19019 36th Ave. W, Suite E Lynnwood, WA BORING LOG:B-6 Page 2 of 2 March 2018 0"S-7 0 20 40 60 25 30 35 40 45 50 See Figure 1, Site and Exploration Plan - 2/18/2018 Holocene Drilling Hollow Stem Auger D50 8 inches Auto 11/2/1250/1 SNM Boring terminated at approximately 25 1/2 feet. Groundwater not observed while drilling. 62 APPENDIX B LABORATORY TESTING PROCEDURES AND RESULTS 63 APPENDIX B LABORATORY TESTING PROCEDURES AND RESULTS A series of laboratory tests were performed by ZGA during the course of this study to evaluate the index and geotechnical engineering properties of the subsurface soils. Descriptions of the types of tests performed are given below. Visual Classification Samples recovered from the exploration locations were visually classified in the field during the exploration program. Representative portions of the samples were carefully packaged in moisture tight containers and transported to our laboratory where the field classifications were verified or modified as required. Visual classification was generally done in accordance with ASTM D 2488. Visual soil classification includes evaluation of color, relative moisture content, soil type based upon grain size, and accessory soil types included in the sample. Soil classifications are presented on the exploration logs in Appendix A. Moisture Content Determinations Moisture content determinations were performed on representative samples obtained from the explorations to aid in identification and correlation of soil types. The determinations were made in general accordance with the test procedures described in ASTM D 2216. Moisture contents are presented on the exploration logs in Appendix A. 200 Wash Analysis A 200 wash analysis indicates the fines content of a sample (percent of sample by weight passing the US No. 200 sieve). 200 wash analyses were performed on representative samples in general accordance with ASTM: D-1140. The results of the 200 wash analyses for the samples were used in classification of the soils, and are presented on the exploration logs in Appendix A. Grain Size Analysis A grain size analysis determines the range in diameter of soil particles included in a particular sample. Grain size analyses were performed on representative samples in general accordance with ASTM D 422. The results of the grain size determinations for the samples were used in classification of the soils, and are presented in this appendix. 64 0 10 20 30 40 50 60 70 80 90 100 0.0010.0100.1001.00010.000100.0001000.000PERCENT FINER BY WEIGHTPARTICLE SIZE IN MILLIMETERS GRAIN SIZE ANALYSIS Comments: 36"12"6"3"1 1/2"3/4"3/8"4 10 20 40 60 140 200 Coarse Medium Fine Silt ClayFineCoarse COBBLESBOULDERS GRAVEL SAND FINE GRAINED SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER Project No.:PROJECT NAME: Village Green Retirement Campus DATE OF TESTING: Exploration Sample Depth (feet)Moisture (%)Fines (%)Description B-3 2 1/2 -4 ft.2.7 Sandy GRAVEL, some siltS-1 5.5 1969.01 2/16/2018 ASTM D 422Test Results Summary Zipper Geo Associates, LLC Geotechnical and Environmental Consultants 65 0 10 20 30 40 50 60 70 80 90 100 0.0010.0100.1001.00010.000100.0001000.000PERCENT FINER BY WEIGHTPARTICLE SIZE IN MILLIMETERS GRAIN SIZE ANALYSIS Comments: 36"12"6"3"1 1/2"3/4"3/8"4 10 20 40 60 140 200 Coarse Medium Fine Silt ClayFineCoarse COBBLESBOULDERS GRAVEL SAND FINE GRAINED SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER Project No.:PROJECT NAME: Village Green Retirement Campus DATE OF TESTING: Exploration Sample Depth (feet)Moisture (%)Fines (%)Description B-5 2 1/2 -4 ft.8.4 Sandy GRAVEL, with siltS-1 13.1 1969.01 2/16/2018 ASTM D 422Test Results Summary Zipper Geo Associates, LLC Geotechnical and Environmental Consultants 66 0 10 20 30 40 50 60 70 80 90 100 0.0010.0100.1001.00010.000100.0001000.000PERCENT FINER BY WEIGHTPARTICLE SIZE IN MILLIMETERS GRAIN SIZE ANALYSIS Comments: 36"12"6"3"1 1/2"3/4"3/8"4 10 20 40 60 140 200 Coarse Medium Fine Silt ClayFineCoarse COBBLESBOULDERS GRAVEL SAND FINE GRAINED SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER Project No.:PROJECT NAME: Village Green Retirement Campus DATE OF TESTING: Exploration Sample Depth (feet)Moisture (%)Fines (%)Description B-6 7 1/2 -9 ft.8.4 Silty SAND, with gravelS-3 31.7 1969.01 2/16/2018 ASTM D 422Test Results Summary Zipper Geo Associates, LLC Geotechnical and Environmental Consultants 67 APPENDIX C EXCERPTS FROM EARTH CONSULTANTS, INC. REPORTS 68 69 70 71 72 73 Village Green of Federal Way DCI 98480.6 Section 7 Other Permits 74 Village Green of Federal Way DCI 98480.6 Section 7 – Other Permits Building, Clearing/Grading and Right-of-Way Use Permits are anticipated after the Process 4 land use approval. 75 Village Green of Federal Way DCI 98480.6 Section 8 CSWPP Plan Analysis and Design 76 Village Green of Federal Way DCI 98480.6 Section 8 – CSWPP Plan Analysis and Design This section will be completed at the final engineering/building permit stage. 77 Village Green of Federal Way DCI 98480.6 Section 9 Bond Quantities, Facility Summaries, and Declaration of Covenant 78 Village Green of Federal Way DCI 98480.6 Section 9 – Bond Quantities, Facility Summaries, and Declaration of Covenant This section will be completed at the final engineering/building permit stage. 79 Village Green of Federal Way DCI 98480.6 Section 10 Operations and Maintenance Manual 80 Village Green of Federal Way DCI 98480.6 Section 10 – Operations and Maintenance Manual This section will be completed at the final engineering/building permit stage. 81 Village Green of Federal Way DCI 98480.6 Appendix A WWHM Report 82 WWHM2012 PROJECT REPORT 83 Prelim WWHM 11/8/2018 1:04:17 AM Page 2 General Model Information Project Name: Prelim WWHM Site Name: Village Green TDA1 Site Address: City: Report Date: 11/8/2018 Gage:Seatac Data Start: 1948/10/01 Data End: 2009/09/30 Timestep: 15 Minute Precip Scale: 1.00 Version Date: 2015/11/05 Version: 4.2.11 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year 84 Prelim WWHM 11/8/2018 1:04:17 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 4.15 C, Lawn, Flat 4.74 Pervious Total 8.89 Impervious Land Use acre ROOF TOPS FLAT 4.16 Impervious Total 4.16 Basin Total 13.05 Element Flows To: Surface Interflow Groundwater Trapezoidal Pond 1 Trapezoidal Pond 1 85 Prelim WWHM 11/8/2018 1:04:17 AM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 6.66 Pervious Total 6.66 Impervious Land Use acre ROOF TOPS FLAT 6.39 Impervious Total 6.39 Basin Total 13.05 Element Flows To: Surface Interflow Groundwater Trapezoidal Pond 2 Trapezoidal Pond 2 86 Prelim WWHM 11/8/2018 1:04:17 AM Page 5 Routing Elements Predeveloped Routing Trapezoidal Pond 1 Bottom Length:150.00 ft. Bottom Width:80.00 ft. Depth:6 ft. Volume at riser head: 2.0878 acre-feet. Side slope 1:3 To 1 Side slope 2:3 To 1 Side slope 3:3 To 1 Side slope 4:3 To 1 Discharge Structure Riser Height:5.54 ft. Riser Diameter:18 in. Orifice 1 Diameter: 2.77 in. Elevation:0 ft. Orifice 2 Diameter: 3.13 in. Elevation:4.6 ft. Element Flows To: Outlet 1 Outlet 2 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 225.26 0.275 0.000 0.000 0.000 225.33 0.277 0.018 0.053 0.000 225.39 0.279 0.037 0.076 0.000 225.46 0.281 0.055 0.093 0.000 225.53 0.284 0.074 0.107 0.000 225.59 0.286 0.093 0.120 0.000 225.66 0.288 0.112 0.131 0.000 225.73 0.290 0.132 0.142 0.000 225.79 0.292 0.151 0.152 0.000 225.86 0.294 0.171 0.161 0.000 225.93 0.297 0.190 0.170 0.000 225.99 0.299 0.210 0.178 0.000 226.06 0.301 0.230 0.186 0.000 226.13 0.303 0.250 0.193 0.000 226.19 0.305 0.271 0.201 0.000 226.26 0.308 0.291 0.208 0.000 226.33 0.310 0.312 0.215 0.000 226.39 0.312 0.333 0.221 0.000 226.46 0.314 0.353 0.228 0.000 226.53 0.316 0.374 0.234 0.000 226.59 0.319 0.396 0.240 0.000 226.66 0.321 0.417 0.246 0.000 226.73 0.323 0.439 0.252 0.000 226.79 0.326 0.460 0.257 0.000 226.86 0.328 0.482 0.263 0.000 226.93 0.330 0.504 0.268 0.000 226.99 0.332 0.526 0.274 0.000 227.06 0.335 0.548 0.279 0.000 227.13 0.337 0.571 0.284 0.000 227.19 0.339 0.593 0.289 0.000 227.26 0.342 0.616 0.294 0.000 227.33 0.344 0.639 0.299 0.000 87 Prelim WWHM 11/8/2018 1:04:17 AM Page 6 227.39 0.346 0.662 0.304 0.000 227.46 0.349 0.685 0.308 0.000 227.53 0.351 0.709 0.313 0.000 227.59 0.353 0.732 0.318 0.000 227.66 0.356 0.756 0.322 0.000 227.73 0.358 0.780 0.327 0.000 227.79 0.361 0.804 0.331 0.000 227.86 0.363 0.828 0.335 0.000 227.93 0.365 0.852 0.340 0.000 227.99 0.368 0.877 0.344 0.000 228.06 0.370 0.901 0.348 0.000 228.13 0.373 0.926 0.352 0.000 228.19 0.375 0.951 0.356 0.000 228.26 0.378 0.976 0.360 0.000 228.33 0.380 1.001 0.364 0.000 228.39 0.382 1.027 0.368 0.000 228.46 0.385 1.052 0.372 0.000 228.53 0.387 1.078 0.376 0.000 228.59 0.390 1.104 0.380 0.000 228.66 0.392 1.130 0.383 0.000 228.73 0.395 1.156 0.387 0.000 228.79 0.397 1.183 0.391 0.000 228.86 0.400 1.209 0.395 0.000 228.93 0.402 1.236 0.398 0.000 228.99 0.405 1.263 0.402 0.000 229.06 0.407 1.290 0.405 0.000 229.13 0.410 1.318 0.409 0.000 229.19 0.412 1.345 0.413 0.000 229.26 0.415 1.373 0.416 0.000 229.33 0.418 1.400 0.419 0.000 229.39 0.420 1.428 0.423 0.000 229.46 0.423 1.456 0.426 0.000 229.53 0.425 1.485 0.430 0.000 229.59 0.428 1.513 0.433 0.000 229.66 0.430 1.542 0.436 0.000 229.73 0.433 1.571 0.440 0.000 229.79 0.436 1.600 0.443 0.000 229.86 0.438 1.629 0.446 0.000 229.93 0.441 1.658 0.518 0.000 229.99 0.444 1.688 0.550 0.000 230.06 0.446 1.717 0.575 0.000 230.13 0.449 1.747 0.596 0.000 230.19 0.451 1.777 0.616 0.000 230.26 0.454 1.807 0.633 0.000 230.33 0.457 1.838 0.650 0.000 230.39 0.459 1.868 0.665 0.000 230.46 0.462 1.899 0.680 0.000 230.53 0.465 1.930 0.694 0.000 230.59 0.468 1.961 0.708 0.000 230.66 0.470 1.992 0.721 0.000 230.73 0.473 2.024 0.734 0.000 230.79 0.476 2.056 0.746 0.000 230.86 0.478 2.087 0.992 0.000 230.93 0.481 2.119 1.485 0.000 230.99 0.484 2.152 2.118 0.000 231.06 0.487 2.184 2.842 0.000 231.13 0.489 2.217 3.609 0.000 231.19 0.492 2.249 4.373 0.000 88 Prelim WWHM 11/8/2018 1:04:17 AM Page 8 Mitigated Routing Trapezoidal Pond 2 Bottom Length:240.00 ft. Bottom Width:90.00 ft. Depth:6.5 ft. Volume at riser head: 3.3834 acre-feet. Side slope 1:0 To 1 Side slope 2:2 To 1 Side slope 3:3 To 1 Side slope 4:3 To 1 Discharge Structure Riser Height:5.8 ft. Riser Diameter:18 in. Orifice 1 Diameter: 2.18 in. Elevation:0 ft. Orifice 2 Diameter: 1.6 in. Elevation:2.05 ft. Orifice 3 Diameter: 0.7 in. Elevation:3.8 ft. Element Flows To: Outlet 1 Outlet 2 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.495 0.000 0.000 0.000 0.0722 0.497 0.035 0.034 0.000 0.1444 0.499 0.071 0.049 0.000 0.2167 0.501 0.108 0.060 0.000 0.2889 0.503 0.144 0.069 0.000 0.3611 0.505 0.180 0.077 0.000 0.4333 0.507 0.217 0.084 0.000 0.5056 0.509 0.254 0.091 0.000 0.5778 0.511 0.291 0.098 0.000 0.6500 0.513 0.328 0.104 0.000 0.7222 0.515 0.365 0.109 0.000 0.7944 0.517 0.402 0.114 0.000 0.8667 0.519 0.439 0.120 0.000 0.9389 0.521 0.477 0.125 0.000 1.0111 0.523 0.515 0.129 0.000 1.0833 0.525 0.553 0.134 0.000 1.1556 0.527 0.591 0.138 0.000 1.2278 0.529 0.629 0.142 0.000 1.3000 0.531 0.667 0.147 0.000 1.3722 0.533 0.706 0.151 0.000 1.4444 0.535 0.744 0.155 0.000 1.5167 0.537 0.783 0.158 0.000 1.5889 0.539 0.822 0.162 0.000 1.6611 0.541 0.861 0.166 0.000 1.7333 0.543 0.900 0.169 0.000 1.8056 0.545 0.939 0.173 0.000 1.8778 0.547 0.979 0.176 0.000 1.9500 0.549 1.018 0.180 0.000 2.0222 0.551 1.058 0.183 0.000 2.0944 0.553 1.098 0.201 0.000 2.1667 0.555 1.138 0.213 0.000 2.2389 0.557 1.178 0.223 0.000 2.3111 0.559 1.219 0.231 0.000 89 Prelim WWHM 11/8/2018 1:04:17 AM Page 9 2.3833 0.561 1.259 0.239 0.000 2.4556 0.563 1.300 0.246 0.000 2.5278 0.566 1.341 0.253 0.000 2.6000 0.568 1.382 0.259 0.000 2.6722 0.570 1.423 0.265 0.000 2.7444 0.572 1.464 0.271 0.000 2.8167 0.574 1.505 0.277 0.000 2.8889 0.576 1.547 0.282 0.000 2.9611 0.578 1.589 0.288 0.000 3.0333 0.580 1.630 0.293 0.000 3.1056 0.582 1.672 0.298 0.000 3.1778 0.584 1.715 0.303 0.000 3.2500 0.586 1.757 0.308 0.000 3.3222 0.588 1.799 0.313 0.000 3.3944 0.591 1.842 0.318 0.000 3.4667 0.593 1.885 0.322 0.000 3.5389 0.595 1.928 0.327 0.000 3.6111 0.597 1.971 0.331 0.000 3.6833 0.599 2.014 0.336 0.000 3.7556 0.601 2.057 0.340 0.000 3.8278 0.603 2.101 0.347 0.000 3.9000 0.605 2.145 0.353 0.000 3.9722 0.608 2.188 0.358 0.000 4.0444 0.610 2.232 0.364 0.000 4.1167 0.612 2.276 0.369 0.000 4.1889 0.614 2.321 0.373 0.000 4.2611 0.616 2.365 0.378 0.000 4.3333 0.618 2.410 0.383 0.000 4.4056 0.620 2.455 0.387 0.000 4.4778 0.623 2.500 0.392 0.000 4.5500 0.625 2.545 0.396 0.000 4.6222 0.627 2.590 0.400 0.000 4.6944 0.629 2.635 0.405 0.000 4.7667 0.631 2.681 0.409 0.000 4.8389 0.633 2.726 0.413 0.000 4.9111 0.636 2.772 0.417 0.000 4.9833 0.638 2.818 0.421 0.000 5.0556 0.640 2.865 0.425 0.000 5.1278 0.642 2.911 0.429 0.000 5.2000 0.644 2.957 0.433 0.000 5.2722 0.647 3.004 0.437 0.000 5.3444 0.649 3.051 0.440 0.000 5.4167 0.651 3.098 0.444 0.000 5.4889 0.653 3.145 0.448 0.000 5.5611 0.655 3.192 0.451 0.000 5.6333 0.658 3.240 0.455 0.000 5.7056 0.660 3.287 0.459 0.000 5.7778 0.662 3.335 0.462 0.000 5.8500 0.664 3.383 0.644 0.000 5.9222 0.667 3.431 1.147 0.000 5.9944 0.669 3.479 1.821 0.000 6.0667 0.671 3.528 2.600 0.000 6.1389 0.673 3.576 3.426 0.000 6.2111 0.676 3.625 4.236 0.000 6.2833 0.678 3.674 4.973 0.000 6.3556 0.680 3.723 5.587 0.000 6.4278 0.682 3.772 6.056 0.000 6.5000 0.685 3.822 6.389 0.000 90 Prelim WWHM 11/8/2018 1:04:17 AM Page 11 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area: 8.89 Total Impervious Area: 4.16 Mitigated Landuse Totals for POC #1 Total Pervious Area: 6.66 Total Impervious Area: 6.39 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.320631 5 year 0.415677 10 year 0.482923 25 year 0.572994 50 year 0.643914 100 year 0.718208 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.292033 5 year 0.415896 10 year 0.51407 25 year 0.658327 50 year 0.781715 100 year 0.919858 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.286 0.220 1950 0.355 0.318 1951 0.621 0.461 1952 0.250 0.175 1953 0.244 0.263 1954 0.318 0.292 1955 0.351 0.292 1956 0.367 0.339 1957 0.302 0.285 1958 0.315 0.308 91 Prelim WWHM 11/8/2018 1:05:00 AM Page 12 1959 0.289 0.241 1960 0.435 0.430 1961 0.292 0.302 1962 0.233 0.168 1963 0.308 0.286 1964 0.302 0.270 1965 0.311 0.325 1966 0.269 0.259 1967 0.338 0.305 1968 0.276 0.267 1969 0.287 0.235 1970 0.290 0.254 1971 0.324 0.304 1972 0.414 0.378 1973 0.279 0.309 1974 0.311 0.301 1975 0.336 0.276 1976 0.326 0.297 1977 0.206 0.178 1978 0.283 0.297 1979 0.226 0.168 1980 0.418 0.436 1981 0.264 0.258 1982 0.401 0.385 1983 0.335 0.296 1984 0.244 0.214 1985 0.266 0.232 1986 0.398 0.356 1987 0.409 0.400 1988 0.264 0.215 1989 0.209 0.218 1990 0.435 0.434 1991 0.522 0.417 1992 0.296 0.300 1993 0.288 0.220 1994 0.189 0.164 1995 0.349 0.313 1996 0.622 0.458 1997 0.647 1.474 1998 0.265 0.224 1999 0.400 0.412 2000 0.287 0.312 2001 0.210 0.156 2002 0.384 0.369 2003 0.246 0.256 2004 0.577 0.454 2005 0.337 0.298 2006 0.323 0.316 2007 0.562 1.052 2008 0.670 0.655 2009 0.385 0.362 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.6695 1.4736 2 0.6475 1.0524 3 0.6223 0.6546 92 Prelim WWHM 11/8/2018 1:05:00 AM Page 13 4 0.6211 0.4612 5 0.5767 0.4580 6 0.5622 0.4542 7 0.5217 0.4364 8 0.4350 0.4336 9 0.4347 0.4296 10 0.4181 0.4167 11 0.4138 0.4115 12 0.4089 0.4003 13 0.4010 0.3847 14 0.4002 0.3783 15 0.3979 0.3688 16 0.3850 0.3616 17 0.3835 0.3561 18 0.3671 0.3387 19 0.3546 0.3254 20 0.3515 0.3182 21 0.3492 0.3160 22 0.3376 0.3130 23 0.3372 0.3122 24 0.3360 0.3094 25 0.3355 0.3079 26 0.3257 0.3048 27 0.3244 0.3043 28 0.3227 0.3020 29 0.3183 0.3006 30 0.3149 0.2999 31 0.3114 0.2978 32 0.3114 0.2973 33 0.3075 0.2972 34 0.3025 0.2963 35 0.3020 0.2919 36 0.2965 0.2919 37 0.2923 0.2860 38 0.2905 0.2848 39 0.2890 0.2758 40 0.2877 0.2704 41 0.2870 0.2675 42 0.2865 0.2627 43 0.2865 0.2591 44 0.2832 0.2581 45 0.2793 0.2556 46 0.2764 0.2539 47 0.2687 0.2408 48 0.2657 0.2346 49 0.2649 0.2323 50 0.2645 0.2241 51 0.2635 0.2203 52 0.2504 0.2199 53 0.2462 0.2178 54 0.2439 0.2153 55 0.2438 0.2142 56 0.2330 0.1781 57 0.2264 0.1749 58 0.2104 0.1685 59 0.2089 0.1678 60 0.2063 0.1635 61 0.1887 0.1562 93 Prelim WWHM 11/8/2018 1:05:00 AM Page 15 Duration Flows The Facility PASSED Flow(cfs) Predev Mit Percentage Pass/Fail 0.1603 92549 91138 98 Pass 0.1652 86175 80721 93 Pass 0.1701 80336 70711 88 Pass 0.1750 75652 62840 83 Pass 0.1799 70433 54092 76 Pass 0.1847 65535 46841 71 Pass 0.1896 60808 45301 74 Pass 0.1945 56338 43933 77 Pass 0.1994 52253 42649 81 Pass 0.2043 48510 41088 84 Pass 0.2092 45195 39398 87 Pass 0.2140 42243 37623 89 Pass 0.2189 39890 35890 89 Pass 0.2238 37067 33880 91 Pass 0.2287 34479 31891 92 Pass 0.2336 32019 30094 93 Pass 0.2385 29902 28148 94 Pass 0.2434 27891 26265 94 Pass 0.2482 25987 24276 93 Pass 0.2531 24105 22415 92 Pass 0.2580 22330 20741 92 Pass 0.2629 20837 19665 94 Pass 0.2678 19190 18236 95 Pass 0.2727 17686 16987 96 Pass 0.2776 16283 15746 96 Pass 0.2824 14946 14215 95 Pass 0.2873 13689 13036 95 Pass 0.2922 12692 11892 93 Pass 0.2971 11967 10866 90 Pass 0.3020 11426 10046 87 Pass 0.3069 10694 9069 84 Pass 0.3117 10021 8421 84 Pass 0.3166 9388 7886 84 Pass 0.3215 8705 7424 85 Pass 0.3264 7961 6953 87 Pass 0.3313 7347 6500 88 Pass 0.3362 6750 6032 89 Pass 0.3411 6406 5630 87 Pass 0.3459 6098 5392 88 Pass 0.3508 5677 5084 89 Pass 0.3557 5307 4849 91 Pass 0.3606 4988 4532 90 Pass 0.3655 4601 4231 91 Pass 0.3704 4325 3953 91 Pass 0.3752 4047 3715 91 Pass 0.3801 3717 3469 93 Pass 0.3850 3356 3178 94 Pass 0.3899 3148 3014 95 Pass 0.3948 2868 2808 97 Pass 0.3997 2588 2599 100 Pass 0.4046 2342 2415 103 Pass 0.4094 2110 2239 106 Pass 0.4143 1901 2035 107 Pass 94 Prelim WWHM 11/8/2018 1:05:00 AM Page 16 0.4192 1671 1810 108 Pass 0.4241 1557 1561 100 Pass 0.4290 1455 1386 95 Pass 0.4339 1288 1183 91 Pass 0.4388 1088 1047 96 Pass 0.4436 939 949 101 Pass 0.4485 818 786 96 Pass 0.4534 806 585 72 Pass 0.4583 795 323 40 Pass 0.4632 785 187 23 Pass 0.4681 776 183 23 Pass 0.4729 767 181 23 Pass 0.4778 752 177 23 Pass 0.4827 741 175 23 Pass 0.4876 732 172 23 Pass 0.4925 718 167 23 Pass 0.4974 707 164 23 Pass 0.5023 691 162 23 Pass 0.5071 682 159 23 Pass 0.5120 670 157 23 Pass 0.5169 656 156 23 Pass 0.5218 628 154 24 Pass 0.5267 607 153 25 Pass 0.5316 577 152 26 Pass 0.5364 545 149 27 Pass 0.5413 509 149 29 Pass 0.5462 483 148 30 Pass 0.5511 458 145 31 Pass 0.5560 434 145 33 Pass 0.5609 403 144 35 Pass 0.5658 368 142 38 Pass 0.5706 340 142 41 Pass 0.5755 300 135 45 Pass 0.5804 273 129 47 Pass 0.5853 253 121 47 Pass 0.5902 240 118 49 Pass 0.5951 227 110 48 Pass 0.6000 215 105 48 Pass 0.6048 198 96 48 Pass 0.6097 180 87 48 Pass 0.6146 163 83 50 Pass 0.6195 138 76 55 Pass 0.6244 105 71 67 Pass 0.6293 94 68 72 Pass 0.6341 86 66 76 Pass 0.6390 79 64 81 Pass 0.6439 73 62 84 Pass 95 Prelim WWHM 11/8/2018 1:05:00 AM Page 17 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. 96 Prelim WWHM 11/8/2018 1:05:00 AM Page 18 LID Report 97 Prelim WWHM 11/8/2018 1:05:30 AM Page 19 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. 98 Prelim WWHM 11/8/2018 1:05:30 AM Page 20 Appendix Predeveloped Schematic 99 Prelim WWHM 11/8/2018 1:05:31 AM Page 21 Mitigated Schematic 100