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20-101386-Drainage Technical Information Report (TIR)-04-22-2021-V3Woodbridge Building A Technical Information Report April 22, 2021 Prepared for Federal Way Campus, LLC 11100 Santa Monica Blvd, Suite 850 Los Angeles, CA 90025 (310) 261 - 4382 Submitted by ESM Consulting Engineers, LLC 33400 8th Avenue S, Suite 205 Federal Way, WA 98003 253.838.6113 tel 253.838.7104 fax www.esmcivil.com 04/22/2021 Table of Contents Section 1. Project Overview Section 2. Conditions and Requirements Summary Section 3. Off-Site Analysis Section 4. Flow Control & Water Quality Facility Analysis and Design Section 5. Conveyance System Analysis and Design Section 6. Special Reports and Studies Section 7. Other Permits Section 8. ESC Analysis and Design Section 9. Bond Quantities, Facility Summaries, & Declaration of Covenant Section 10. Operations and Maintenance Manual List of Figures 1.1 Vicinity Map 1.2 Existing Site Conditions 1.3 Proposed Site Conditions 3.1 Site Topography 3.2 Drainage Complaints & Environmental Hazards 3.3 Downstream Analysis Flow Path 5.1 Onsite Conveyance Sub-basin Delineation Appendix A Basin Exhibits B Hydrology Model Output C Geotechnical Engineering Services Report D Appeal Hearing Memorandum E TIR Addendum - SEPA MDNS #12 Response Letter F Hydrology Model Output - Downstream Wetland Volume Analysis \\esm8\engr\esm-jobs\1886\001\016-0015\document\rprt-005.docx 1. Project Overview The purpose of this report is to encapsulate the documents and analysis required by the Drainage Review in the 2016 King County Surface Water Design Manual (SWDM) and the subsequent conditions required by the hearing examiner. The Executive Proposed Hylebos Creek and Lower Puget Sound Basin Plan by King County Surface Water Management Division dated July 28, 1991, (Basin Plan) has been reviewed in accordance with the hearing examiner’s condition that resulted from the appeal process. This report will also show that the project is compliant and consistent with the intent of the Basin Plan, refer to the memorandum by ESM Consulting Engineers, LLC, dated February 7, 2020, included in Appendix D of this report for more information. Existing Site: The proposed Woodbridge Building A project site is located in the northeast quarter of Section 21, Township 21 North, Range 4 East, W.M. in the City of Federal Way, WA. More specifically, the project site is located between Weyerhaeuser Way S and the private loop road that serves the Headquarters building, and south of the roundabout at 33rd Place S. The property is zoned CP-1 and is subject to the Concomitant Pre-Annexation Zoning Agreement dated August 23, 1994. Figure 1.1 shows the Vicinity Map. Existing Site Hydrology: The existing site is generally forested with a mix of large evergreen and deciduous trees. There is approximately 40 feet of fall across the property from the northwest corner to the southeast corner of the site (to Stream EA). The site is mostly undeveloped, with gravel trails and maintenance roads throughout, along with storage areas for landscape materials (topsoil, gravel, etc.) as shown in Figure 1.2. See Section 3 for more information. Proposed Site Improvements: The proposed development consists of a single-story warehouse building with parking & landscaped areas around the building structure on a 15.46-acre parcel. Additionally, there will be pedestrian connectivity improvements along the west side of Weyerhaeuser Way S (landscape planter and sidewalk). The 50-foot wide managed forest buffer that extends along the property frontage on Weyerhaeuser Way S will be preserved with this development, with the exception of one driveway and one sidewalk penetration for access. The remainder of the frontage improvements will be deferred until Building B’s development. The remaining area south of the proposed Building A will be developed at a later date, as Building B. Stormwater runoff from the proposed Building A and future Building B will be collected in a piped storm drainage system and conveyed to a proposed detention pond located at the south end of the property. Depending on timing for design and construction of the Building A and B projects, the detention pond will either be constructed for both projects at one time, or with Building A, to then be extended to the south, at a later date, for the Building B future development. Water quality will be provided using a Modular Wetlands filter vault (or approved equivalent) to be placed following detention. Figure 1.3 illustrates the proposed and future development site conditions. Proposed Site Hydrology: The proposed onsite stormwater conveyance system will collect and convey runoff from the developed Building A project site south through the existing 24-inch diameter CMP culvert beneath highway 18, which is a natural discharge location for the project site. See Sections 4 and 5 of this report for more information. Stormwater Runoff Mitigation Standard: The project will be subject to Full Drainage Review per the City of Federal Way Addendum to the Surface Water Design Manual and the 2016 King County Surface Water Design Manual which has been adopted by the City. In addition to the current stormwater mitigation standards, the project (per the decision following the appeal hearing) is also required to demonstrate compliance and consistency with the Executive Proposed Hylebos Creek and Lower Puget Sound Basin Plan by King County Surface Water Management Division, dated July 28, 1991 (Basin Plan). Those additional standards (and how they relate to this project) are documented in the memorandum by ESM Consulting Engineers, LLC, dated February 7, 2020, which is included in Appendix D of this report. The stormwater requirements in these codes will collectively be referred to in this report as the SWDM. Based on the SWDM, the project site will comply with the conservation flow control design criteria generated by an approved hydrology model, included in software such as the DOE version of the 2012 Western Washington Hydrology Model (WWHM), and provide enhanced water quality treatment. Additionally, as detailed in the pre-application meeting notes and submittal comments, the proposed development must comply with Level 2 (Conservation) Flow Control standards per the SWDM. There are no anticipated adverse downstream impacts under the Level 2 standards, refer to Section 4 of this report for more information. There are no anticipated adverse downstream impacts under the Level 2 standards; however, the project has voluntarily elected to comply with the more stringent Level 3 Flow Control standards with additional factor of safety in the detention volume provided. Level 3 Flow Control standards per the 2016 SWDM are equivalent to the most stringent standard defined in the 1991 Basin Plan (BW-3), refer to Section 4 of this report for a comparison of mitigation criteria. WWHM was used to design the proposed flow control and water quality facilities. Procedures and design criteria specified in the SWDM were followed to construct the hydrology model for this project. The resultant flow control and water quality facility sizes generated from that hydrology model are compliant with the required mitigation standards for the project site. WWHM is a continuous runoff modeling software that utilizes a calibrated Hydrologic Simulation Program Fortran (HSPF) computation engine to process the runoff data and perform routing computations to determine the runoff rate thresholds and detention volume requirements. Conservation flow control and enhanced water quality treatment for stormwater runoff will be provided within a detention pond and a Modular Wetlands filter vault (or approved equivalent) that will be located along the south boundary of the site following detention. The flow control facility will discharge south to existing Stream EA and the associated 24-inch diameter corrugated metal pipe (CMP) culvert which eventually combines with the East Branch Hylebos Creek, located approximately 1 mile downstream. See Section 3 for the Level 1 Downstream Analysis and Section 4 for the flow control and water quality analysis. Soils on the Project Site: The Geotechnical Engineering Services Report (Appendix C) maps the soils onsite to include Vashon-age Glacial Till (map symbol Qvt). Flow Control BMP’s: All applicable Flow Control BMP’s are listed and explained in Section 4 of this report. Date: 6/8/2016 Notes: ±The information included on this map has been compiled by King County staff from a variety of sources and issubject to change without notice. King County makes no representations or warranties, express or implied,as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intendedfor use as a survey product. King County shall not be liable for any general, special, indirect, incidental, orconsequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuseof the information contained on this map. Any sale of this map or information on this map is prohibited except bywritten permission of King County. King County iMap n WEYERHAEUSER WAY S.WEYERHAEUSER WAY S.LOOP ROA D LOOP ROAD L L CFederal Way, WA 9800333400 8th Ave S, Suite 205C O N S U L T I N G E N G I N E E R SFEDERAL WAY CAMPUS LLCWOODBRIDGE BUILDING "A"SCALE: 1" = 200' FIGURE 1.2 PROJECT SITE n WEYERHAEUSER WAY S.WEYERHAEUSER WAY S.LOOP ROA D LOOP ROAD WOODBRIDGE BUILDING "A"L L CFederal Way, WA 9800333400 8th Ave S, Suite 205C O N S U L T I N G E N G I N E E R SFEDERAL WAY CAMPUS LLCWOODBRIDGE BUILDING "A"SCALE: 1" = 200' FIGURE 1.3 2. Conditions and Requirements Summary Review of the 9 Core Requirements and 5 Special Requirements This section describes how the project will meet the SWDM Core and Special Requirements. Core Requirement No. 1 Discharge at the Natural Location For pre-developed conditions, the Building A project site drains to the south, overland, via sheet flow and generally collects at the southeast corner, in Stream EA, then continues in an existing 24-inch diameter CMP culvert beneath Highway 18 and into a wetland area. A portion of the future Building B project site (4 acres) is estimated to drain to the southwest corner of that parcel to the Weyerhaeuser Pond outlet channel. The stormwater runoff from Building A and future Building B combines within approximately 1/2 mile downstream of the project site and continues downstream as part of the East Branch Hylebos Creek, approximately 1 mile downstream. For the proposed Building A development, the detention pond will match the pre-developed condition and discharge pre-developed forested stormwater runoff at the Stream EA location. For the combined proposed Building A and future Building B development, the combined discharge from the detention pond will be evaluated as part of the Building B Technical Information Report (TIR) to either discharge pre-developed forested stormwater runoff to the same Stream EA location, or use a flow-splitter to discharge a portion of the stormwater runoff to the Weyerhaeuser Pond outlet channel. Core Requirement No. 2 Off-site Analysis The off-site analysis has been documented in Section 3 of this report. Core Requirement No. 3 Flow Control The project is required to provide Level 2 (Conservation) flow control and to release stormwater at the rate that complies with the approved hydrology model per the SWDM, the pre-application meeting notes, and city comments for this project. That flow control standard is estimated to be met with a detention pond. See Section 4 of this report for more information. Core Requirement No. 4 Conveyance System Stormwater conveyance will be provided by the proposed conveyance system per Section 5. Calculations for the conveyance and backwater analysis are provided in section 5 of this report. Core Requirement No. 5 Erosion and Sediment Control Erosion and sediment controls to prevent the transport of sediment from the project site to downstream drainage facilities, water resources, and adjacent properties will be provided on the construction plans. Core Requirement No. 6 Maintenance and Operations The Operations and Maintenance manual is included in section 5 of this report. Core Requirement No. 7 Financial Guarantees and Liability All drainage facilities constructed or modified for projects will comply with the financial guarantee requirements as provided in the King County Bond Quantities Worksheet. Bond Quantities are provided in Section 9 of this report. Core Requirement No. 8 Water Quality Enhanced water quality treatment will be provided in a Modular Wetlands filter vault (or approved equivalent) following detention. See Section 4 of this report for details. Core Requirement No. 9 Flow Control BMP’s All applicable Flow Control BMP’s are listed and discussed in Section 4 of this report. Special Requirement No. 1 Other Adopted Area-Specific Requirements There are no master drainage plans, basin plans, salmon conservation plans, stormwater compliance plans, flood hazard reduction plan updates, or shared facility drainage plans for this project. Special Requirement No. 1 does not apply. Special Requirement No. 2 Flood Hazard Area Delineation The developed project site location is not in a 100-year floodplain. Special Requirement No. 2 does not apply. Special Requirement No. 3 Flood Protection Facilities The developed project site is not protected by an existing flood protection facility. The proposed site improvements do not include the modification of an existing flood protection facility. Special Requirement No. 3 does not apply. Special Requirement No. 4 Source Control The project will follow the King County Stormwater Pollution Prevention Manual and King County Code 9.12 to identify and implement source controls as needed. Due to the proposed use of the project site, source control is not required; therefore, Special Requirement No. 4 does not apply. Special Requirement No. 5 Oil Control The proposed development is commercial and (according to the definition provided in the SWDM) qualifies as a “high-use site” due to vehicle fleet size; therefore, Special Requirement No. 5 does apply. Implementation details regarding oil control are provided on the construction plans and oil control sizing calculations are provided in Section 4 of this report. 3.Off-Site Analysis A Level 1 downstream analysis has been performed for the site. Task 1: Study Area Definition and Maps The study area consists of the project site and 1/4 mile downstream flow path for runoff released from the existing site. Figure 1.2 shows the existing site conditions. Figure 3.3 shows the extent of offsite analysis and the downstream flow path from the project site. Task 2: Resource Review Flow Control Map According to the SWDM, the project site is required to meet Conservation Flow Control standards. Soil Survey Map The Geotechnical Engineering Services Report (Appendix C) maps the soils onsite to include Vashon-age Glacial Till (map symbol Qvt). King County iMap According to iMap, the project site is NOT mapped in any of the following areas: - 100 Year Floodplains - Seismic Hazard Areas - Landslide Hazard Areas - Coal Mine Hazard Areas - Erosion Hazard Areas - Critical Aquifer Recharge Area King County iMap and the Pre-Application Conference Notes The project site has the following areas mapped onsite and nearby: - Streams & Wetlands See Figure 3.2 for more information regarding the environmental hazards near the project site. Road Drainage Problems None noted Wetlands Inventory According to iMap, the Critical Areas Review, and the 1990 King County Wetlands Inventory Notebooks there are no recorded wetlands on the developed project site. However, the wetland biologist has located onsite wetland areas and there are wetland areas downstream of the developed project site. See Figure 1.2 for Existing Site Conditions and the wetland report for more information. Migrating River Study None noted Downstream Drainage Complaints According to iMap, there are no relevant downstream drainage complaints within the scope of this project. According to City of Federal Way staff, in 2011, the roundabout adjacent to the north side of the property flooded due to leaves blocking a catch basin grate. Once the leaves were removed the flooding subsided. This complaint was considered resolved and not relevant Task 3: Field Inspection (Level 1 Inspection) A Level 1 Downstream Analysis was completed by ESM Consulting Engineers, LLC in the afternoon on June 06, 2016, when it was partly cloudy and 74°F. During the inspection it was found that the project site has no apparent upstream offsite areas draining to the property. The flows from the project site drain to an offsite stream (East Branch Hylebos Creek). There did not appear to be any flooding issues over any of the roadways adjacent to the project site. The runoff from the project site collects along the north side of a gravel footpath that extends beyond the south boundary of the project site. From there, the runoff is estimated to flow along the path and through a culvert to the south side of the footpath. From there, runoff continues through vegetation, to Stream EA and into a 24-inch CMP culvert beneath the onramp of west-bound Highway 18 to rehydrate further downstream wetlands. The outlet side of that culvert is open and free flowing. From this location, the flow meanders through the wetlands and exits at the western parcel boundary, as shown on Figure 3.3. Stormwater runoff from the southwest portion of the parcel (4 acres), south of the project site, on the future development Building B site, is estimated to drain to the southwest corner of that parcel to the Weyerhaeuser Pond outlet channel. Another downstream analysis was completed on February 19, 2018, when it was sunny and 40°F to verify the culvert size and capacity at the location that stormwater from the Weyerhaeuser Pond outlet channel crosses beneath Highway 18. There are two existing culverts (estimated at 48” and 24” diameters) at Point 9 shown on Figure 3.3 and they are unobstructed. Daylight could be seen through the inlet side of the 48” culvert and, from there, the outlet also appeared to be unobstructed. See Figures 3.1 & 3.3 (Site Topography & Offsite Downstream Flowpath respectively) for further information. Task 4: Drainage Description and Problem Descriptions According to iMap, the project site is in the Hylebos Creek (King County WRIA number: 10) drainage basin. The East Branch Hylebos Creek is located to the south of the project site. No drainage problems are estimated to exist in the site’s existing condition. The proposed development discharges to Stream EA. The Stream EA continued drainage path to the property south of the freeway is an established drainage route through a 24-inch diameter culvert and the runoff from the developed project site will maintain the flow rate and duration of the pre-developed land cover (which is very similar to the existing land cover). Therefore, no significant adverse impact is anticipated to downstream conditions. Task 5: Mitigation of Existing or Potential Problems No existing or potential problems were observed with the existing drainage system within the scope of the downstream analysis; therefore, no further mitigation is proposed. - Date: 3/10/2017 Notes:±The information included on this map has been compiled by King County staff from a variety of sources and is subject tochange without notice. King County makes no representations or warranties, express or implied, as to accuracy,completeness, timeliness, or rights to the use of such information. This document is not intended for use as a surveyproduct. King County shall not be liable for any general, special, indirect, incidental, or consequential damages including,but not limited to, lost revenues or lost profits resulting from the use or misuse of the information contained on this map.Any sale of this map or information on this map is prohibited except by written permission of King County. Legend Parcels - Date: 3/10/2017 Notes:±The information included on this map has been compiled by King County staff from a variety of sources and is subject tochange without notice. King County makes no representations or warranties, express or implied, as to accuracy,completeness, timeliness, or rights to the use of such information. This document is not intended for use as a surveyproduct. King County shall not be liable for any general, special, indirect, incidental, or consequential damages including,but not limited to, lost revenues or lost profits resulting from the use or misuse of the information contained on this map.Any sale of this map or information on this map is prohibited except by written permission of King County. Legend Parcels Bonded Commercial-MF Commercial-SF Construction DOT FMD Regional Residential Drainage complaints Potential landslidehazard areas (2016,see explanation--->) Potential steep slopehazard areas (2016,see explanation--->) Erosion hazard (1990SAO) Seismic hazard (1990SAO) Coal mine hazard(1990 SAO) class 1 class 2 perennial class 2 salmonid class 3 unclassified Wetland (1990 SAO) Sensitive area noticeon title \\esm8\engr\ESM-JOBS\1886\001\016-0015\gis\werer.mxd Date: 8/25/2017User: SavannaN Greenline Warehouse "A"Offsite Downstream F lowpath0300150 1 in = 300 ft TIR Exhib it Le gend Existing Stream / Creek Existing Site Flowplath Proposed Warehouse "A" Conceptual Future Site Figure 3.3Data Source: Existing Stream / Creek provided by King County GIS (wtrcrs_line 2017).Aerial imagery provided by Aerial Express (2012). Although careful techniques are used in creating and displaying GIS data, ESM cannot guarantee accuracy of the information contained on this map. At Point #1 looking south along estimated drainage path Storm water runoff from the project site is estimated to collect in along the west side of this gravel trail and flow south to Point #2. At Point #2 looking south Runoff is estimated to continue in this ditch and flow southwest in parallel with a footpath to Point #3. At Point #3 looking west along gravel footpath At Point #3 looking west along drainage ditch Runoff is estimated to continue southwest in this ditch to Point #4. At Point #4 looking west Runoff in this ditch is estimated to flow across the footpath at Point #4 through this culvert. At Point #4 looking south Runoff continues offsite toward the white maker on the north side of Highway 18, west- bound, shown here. At the white maker shown in the previous photo According to the wetland report, runoff continues offsite in this 24” CMP culvert beneath the onramp of west-bound Highway 18 to rehydrate further downstream wetlands. It is estimated to drain to Hylebos Creek. At Point 5 looking north This is the 24” culvert outlet. It appears to have a small amount of sediment build-up but otherwise appeared to be unobstructed. At Point 5 looking south The runoff from the culvert continues into the wetland area shown. At Point 6 looking east This is the drainage ditch that conveys a small portion of the runoff from the future development site. Stormwater collects along the south side of the road shown and continues to the south to Point 7. At Point 6 looking south This is the drainage ditch that conveys a small portion of the runoff from the future development site (not flowing during the visit). Stormwater collects along the south side of the road shown and continues to the south to Point 7. At Point 7 looking south The runoff from the meadow was observed collecting in the drainage channel between Point 6 and Point 7. That drainage channel continued into a patch of briar until Point 8 At Point 8 looking southwest Runoff continued to collect and build in the drainage channel from offsite areas. At Point 9 looking south Runoff at Point 9 was conveyed beneath Highway 18 through these culverts (approximately 48” and 24” from left to right in the photo). There appeared to be no obstructions for either culvert inlet. At Point 9 looking into the 48” culvert The other end of the 48” culvert can be seen in the photo. During the site visit, it was noted that it did not appear to be obstructed (due to the silhouette of the outlet). 4. Flow Control & Water Quality Facility Analysis and Design Existing Site Hydrology: The existing project site is generally forested with a mix of large evergreen and deciduous trees. There is approximately 40 feet of fall across the property from the northwest corner to the southeast corner of the site. The site is mostly undeveloped; however, it does contain gravel trails and maintenance roads throughout, along with storage areas for landscape materials (topsoil, gravel, etc.). There are eight small wetlands and a stream located on, or immediately adjacent to the site, which are hydraulically connected at high water levels, due to the existing soil type, and water moves laterally between them. For detailed information on the wetlands being removed or retained, see the Critical Areas Report revised by Talasaea Consultants on March 29, 2017 (and Revised August 25, 2020), included with this submittal under separate cover. Stormwater runoff from the existing Building A drainage basin is collected at the site’s southern boundary in Stream EA and routed to a 24-inch diameter CMP culvert beneath Highway 18. Refer to Section 3 for more information. Developed Site Hydrology: The proposed drainage basins for Building A and the affected areas within the future Building B parcel are detailed in Table 4.1 and shown on the Developed Basins Exhibit (Appendix A). The sub-basin areas shown on Table 4.1 account for the areas disturbed on the project site, which are mitigated by the onsite detention facility. The project contains a managed forest buffer as well as undisturbed forest area, the runoff from which bypasses the onsite detention system. Since this area (3.25 acres) is forested and will remain undisturbed, the areas are excluded from the accompanying WWHM calculations because, by definition, they comply with the required level of flow control as defined by the SWDM. Table 4.2 shows the combined Buildings A and future Building B areas. The pedestrian connectivity improvements along the Weyerhaeuser Way S (0.37 acres of sidewalk for Building A) are proposed to bypass the detention pond, which is acceptable, because this area (estimated 0.78 acres of sidewalk for combined Buildings A & B, 0.48 acres will be undetained and 0.28 will be mitigated by the onsite detention facility) generates an increase in the 100 year peak flow rate of 0.36 cfs, which is less than 0.4 cfs. The detention pond also over-detains for the frontage improvements within the factor of safety. Table 4.1 Pond Drainage Basin (Acres) Total Building A Developed Building A Right-of-way Areas for Building A Improvements on Future Developed Building B Parcel for Building A Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Forest 18.63 0.92 0.00 17.71 4.17 0.92 0.00 3.25 0.00 0.00 0.00 0.00 14.46 0.00 0.00 14.46 Grass 1.29 1.22 0.07 0.00 1.27 1.20 0.07 0.00 0.00 0.00 0.00 0.00 0.02 0.02 0.00 0.00 Pond Tract (Grass)1.94 1.94 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.94 1.94 0.00 0.00 Roof 5.19 5.19 0.00 0.00 5.19 5.19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Pavement 6.04 5.21 0.35 0.48 4.83 4.76 0.07 0.00 0.78 0.02 0.28 *0.48 0.43 0.43 0.00 0.00 Pervious 21.86 4.08 0.07 17.71 5.44 2.12 0.07 3.25 0.00 0.00 0.00 0.00 16.42 1.96 0.00 14.46 Impervious 11.23 10.40 0.35 0.48 10.02 9.95 0.07 0.00 0.78 0.02 0.28 *0.48 0.43 0.43 0.00 0.00 Total **33.09 14.48 0.42 18.19 **15.46 12.07 0.14 3.25 **0.78 0.02 0.28 *0.48 **16.85 2.39 0.00 14.46 * Pedestrian connectivity improvements along Weyerhaeuser Way S ** Total ROW improvements have increased and the project site parcel areas have changed since the preliminary submittal, the areas shown reflect the final recorded areas. Table 4.2 Pond Drainage Basin (Acres) Combined Buildings A & B Developed Building A Right-of-way Areas for Building A Future Developed Building B Total Detained Bypass Un- Detained Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Forest 8.32 0.92 0.00 7.40 4.17 0.92 0.00 3.25 0.00 0.00 0.00 0.00 4.15 0.00 0.00 4.15 Grass 2.72 2.65 0.07 0.00 1.27 1.20 0.07 0.00 0.00 0.00 0.00 0.00 1.45 1.45 0.00 0.00 Pond Tract (Grass)1.94 1.94 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.94 1.94 0.00 0.00 Roof 10.10 10.10 0.00 0.00 5.19 5.19 0.00 0.00 0.00 0.00 0.00 0.00 4.91 4.91 0.00 0.00 Pavement 10.01 9.15 0.38 0.48 4.83 4.76 0.07 0.00 0.78 0.02 0.28 *0.48 4.40 4.37 0.03 0.00 Pervious 12.98 5.51 0.07 7.40 5.44 2.12 0.07 3.25 0.00 0.00 0.00 0.00 7.54 3.39 0.00 4.15 Impervious 20.11 19.25 0.38 0.48 10.02 9.95 0.07 0.00 0.78 0.02 0.28 *0.48 9.31 9.28 0.03 0.00 Total **33.09 24.76 0.45 7.88 **15.46 12.07 0.14 3.25 **0.78 0.02 0.28 *0.48 **16.85 12.67 0.03 4.15 * Pedestrian connectivity improvements along Weyerhaeuser Way S ** Total ROW improvements have increased and the project site parcel areas have changed since the preliminary submittal, the areas shown reflect the final recorded areas. Performance Standards: Stormwater systems onsite are to be designed to mitigate runoff generated from the project per the requirements of the SWDM, specifically the Conservation Flow Control standards in Section 1.2.3.1.B. The facility size is required to be determined by an approved hydrology model per the SWDM. The approved hydrology model used to size the stormwater detention and water quality facilities was the 2012 Western Washington Hydrology Model (WWHM). The Hydrologic Simulation Program Fortran (HSPF) is the computation software that is executed from within WWHM to perform the continuous runoff stormwater modeling. Due to the size and location of the proposed development, the project is required to comply with Conservation Flow Control (Level 2) standards. There are no anticipated adverse downstream impacts under the Level 2 standards; however, the project has voluntarily elected to comply with the more stringent Level 3 Flow Control standards with additional factor of safety in the detention volume provided. Level 3 Flow Control standards (defined under Level 3 on page 3-6 of the 2016 SWDM) states: Level 3 Flow Control … This standard requires maintaining the durations of high flows at their predevelopment levels for all flows greater than one-half of the 2-year flow up to the 50-year flow and holding the 100-year peak flow rate at its predevelopment level. The predevelopment peak flow rates for the 2-year and 10-year runoff events are also intended to be maintained when applying Level 3 flow control. Those flow control requirements are estimated to be met with a stormwater detention pond, as described in this section under Flow Control System. Furthermore, this project is subject to compliance and consistency with the 1991 Basin Plan. There were no requirements imposed specifically on the project site, but the basin-wide requirements are applicable for subcatchment H8 (which contains the project site) shown on Figure 2.3.2 of the Basin Plan. The indicated priority for development in the higher subcatchment areas of the East Branch Hylebos Creek Sub-Basin are flow control mitigation to prevent further scouring of the ravine that conveys stormwater runoff down through Milton. The most stringent flow control criteria within the Basin Plan (defined under BW-3 on page 3-6 of the 1991 Basin Plan) states: BW-3:Stream Protection Onsite Detention Standard In subcatchments where future flows are expected to have significant adverse impacts on stream stability and habitat, onsite detention ponds for new development, including public and private streets and highways, should be designed such that post- development flow peaks and durations are reduced to pre-development levels for flows greater than 50 percent of the 2-year and less than the 50-year. In addition, the 100-year post-development peak flow should be reduced to the 100-year pre- development level. The recommended method of designing these detention ponds is a calibrated continuous hydrologic model, preferably HSPF. HSPF (as noted above) is used by WWHM in the current approved hydrology model and is the preferred method per the Basin Plan. The BW-3 standard is nearly identical to the modern Level 3 Flow Control mitigation standard defined in the current SWDM, except that Level 3 allows the 100-year peak flow rate target to be calculated from the existing site conditions. Instead, for this project site the 100-year peak flow rate target will be conservatively calculated from pre-developed (forest) conditions. The newer standard also requires that the developed condition 2-year & 10-year peak flows more conservatively match the pre-developed (forested) condition 2-year & 10- year peak flows. To meet the intent of this flow rate matching standard, the project will conservatively release stormwater at rates that are strictly less than the pre-developed flow rates for the given return periods. Due to the type of development being commercial, the required water quality treatment standard is Enhanced Basic WQ treatment per Section 1.2.8.1.A of the SWDM. Those treatment requirements are estimated to be met with a proprietary treatment system, as described in this section under Water Quality System. Enhanced Basic WQ treatment standards per the 2016 SWDM are compliant and consistent with the 1991 Basin Plan. Flow Control System: The sizing from WWHM complies with the Conservation Flow Control standards. The developed project site flow rates are given in Table 4.3 and comply with the more stringent Level 3 Flow Control standards (as defined above). The proposed detention facility includes approximately 1.0 foot of sediment storage, 7.5 feet of live storage, 1.0 foot of freeboard for the primary overflow, and 1.0 foot for the emergency overflow, which totals 11 feet from the bottom of the sediment storage within the pond to the top of the access berm. The volume required, volume provided, and safety factor are given in Table 4.4. Depending on timing for design and construction of the Building A and B projects, the detention pond will either be constructed for both projects at one time, or with Building A, to then be extended to the south, at a later date, for the Building B future development. The WWHM output for Flow Control for Building A and Building A with an estimated lot coverage for the Building B parcel is provided in Appendix B. Final flow control design and calculations for Building B will be provided in the Building B report. Table 4.3 Return Period Predeveloped Building A ( cfs ) Mitigated Building A ( cfs ) Predeveloped Combined ( cfs ) Mitigated Combined ( cfs ) 2 Year 0.4381 0.3445 0.741 0.4776 5 Year 0.688 0.4846 1.164 0.6870 10 Year 0.8297 0.5902 1.403 0.8474 25 Year 0.9797 0.739 1.657 1.0766 50 Year 1.0726 0.8615 1.814 1.2677 100 Year 1.1515 0.9945 1.948 1.4770 Table 4.4 Stormwater Detention Volume Total Building A (Cu Ft) Total Combined (Cu Ft) Required 224,000 436,000* Provided 326,000 443,000* Safety Factor 31%- * Conservatively estimated, final design and volume requirements will be provided with the Building B report. The frontage improvements for this project are to be deferred until such time as new development exceeds 300,000 square feet per Section 15 of the Weyerhaeuser Company Concomitant Pre-Annexation Zoning Agreement, dated August 23, 1994. This project has set aside adequate right-of-way to accommodate these improvements. Downstream Wetland Hydration: Within the downstream discharge corridor for the project, the triangle parcel wetland is hydrated by the discharge from the project area and approximately 200 acres of additional existing upstream tributary area. That additional existing area has been assumed to be unmitigated with 50% of the land use area modeled as Till Grass and the remaining 50% modeled as Road (impervious). Per Reference 5, Guide Sheet 3B of the SWDM, the project site must maintain the average wetland recharge volume for a single event (on average) within 20% of predeveloped conditions (assumed forest for the project site, existing for the additional tributary area) and 15% for a given month (on average). The basins area approximately delineated and shown on a figure preceding the hydrology model output in Appendix F of this report. In summary, the onsite stormwater mitigation system is sufficient to maintain the wetland hydrology within acceptable thresholds per the SWDM. Water Quality System: Enhanced water quality treatment will be provided using a Modular Wetlands filter vault (or approved equivalent), per Section 1.2.8 of the SWDM. Depending on timing for design and construction of the Building A and B projects, water quality for the future Building B will either be provided in the same Modular Wetlands filter vault, or an additional vault will be added at a later date, for the Building B future development. The facility’s Building A and combined Buildings A and B required flow rates are given in Table 4.5. The Water Quality treatment requirement is the full 2-year release rate from the detention facility (POC 4 in the WWHM output), those rates are summarized in Table 4.5. Table 4.5 Water Quality Building A Flow ( cfs ) Combined Flow ( cfs ) Required 0.2786 0.4395* * Final design flow to be provided with the Building B report The roof material to be used on the proposed building will be TOP and is considered to be non-leaching which complies with the requirements specified in Section 1.2.8 of the SWDM. The pedestrian connectivity improvements along Weyerhaeuser Way S are considered non-pollution generating and will not require water quality treatment. Oil control is required for the area that will receive regular truck traffic onsite. All flows that mix with the stormwater collected from the surface that requires oil control treatment must also be treated; hence, the pervious areas and northerly passenger car parking lot area (and associated runoff rates) have been included in the oil/water separator design. The stormwater system will be designed to convey building roof runoff separate from the parking lot surface that drains to the oil/water separator (to minimize the size of the separator). The approximate area to be treated for oil control is 2.41 acres and it generates an offline treatment flow rate of 0.2163 cfs (POC #2 in the hydrology model output in Appendix B). Per Section 6.2.1 of the SWDM, the 2-year 24-hour precipitation may be converted directly to the 6-month 24-hour precipitation by multiplying the former by a factor of 0.72. The resultant 6-month 24-hour precipitation depth is 1.476 inches, which is rounded up to 1.5 inches on Table 6.2.1.A to determine the k factor for the project site. Equation 6-33 from Section 6.6.2.1 of the SWDM is as follows:ܣ௛ =60∗ܳ0.00386 ∗ቀܵ௪ −ܵ௢ߤ ቁ Where ܵ௪ =specific gravity of water = 1.0ܵை=specific gravity of water = 0.85ߤ =absolute viscosity of water; use 0.015674 for temp = 39° Fܳ =modified off-line water quality design flow rate per Section 6.2.1 (cfs)ܣ௛ =required effective (horizontal) surface area of plate media (sf). Which simplifies to:ܣ௛ =ܳ ∗଺଴଴.଴଴ଷ଼଺ ∗ቀభ.బ ష బ.ఴఱబ.బభఱలళర ቁ =ܳ ∗1624 The offline flow rate for the oil/water separator, as computed by WWHM on POC 2, is 0.2163 cfs. The modified offline flow rate (per Section 6.2.1 of the SWDM) is calculated from the offline flow rate multiplied by the site-specific offline k factor: 0.2163 x 3.68 = 0.80 cfs. The factor to convert from cfs to gpm is 448.9 gpm/cfs; therefore, the oil/water separator must be able to treat at least 357 gpm and have a plate area of at least 1,299 square feet. Q_wq = 0.2163 cfs -> Offline water quality treatment flow rate k = 3.68 -> adjustment factor from Table 6.2.1.AQ = Q_wq * k Q = 0.2163 * 3.68 = 0.80 cfs (357 gpm) -> Modified Offline flow rate࡭ࢎ=ܳ ∗1624 = 0.80 ∗1624 =૚૛ૢૢ ࢙ࢌ The Oldcastle 612-2-cps unit has 1,776 square-feet of plate area and treats 420 gpm, which is sufficient for this project site. A flow splitter will take runoff from POC 2 (which represents the northerly parking lot and truck use area, 100-year flow rate of 1.841 cfs) and divert all flows up to the modified offline treatment flow rate (0.80 cfs) to the oil/water separator. Any flows in excess of the treatment rate will bypass the oil/water separator. The flow splitter will have a riser with a single orifice at the bottom to regulate flows into the oil/water separator while the high flow bypass will occur via the downstream pipe connection without a riser. The treatment flow orifice will have 0.5-feet of head and will need to be 6.5” in diameter to convey the 0.8 cfs treatment flow. In summary, enhanced water quality treatment will be provided for Building A and future Building B using a Modular Wetlands filter vault (or approved equivalent). Based on the Washington State Department of Ecology approval, the filters will be sized with the 2-year mitigated flow rate (computed by WWHM). Oil/water separation will be provided by a coalescing plate filter vault preceding detention. The WWHM output for Water Quality is provided in Appendix B. SECTION 3.2 RUNOFF COMPUTATION AND ANALYSIS METHODS 1/9/2009 2009 Surface Water Design Manual 3-14 FIGURE 3.2.1.A 2-YEAR 24-HOUR ISOPLUVIALS SNOHOMISH COUNTY KING COUNTY KING COUNTY PIERCE COUNTY KIRKLAND REDMOND REDMOND DUVALL WOODINVILLE BOTHELL MERCER ISLAND RENTON TUKWILA SEATTLE SEATTLE BURIEN NORMANDY PARK SEATAC BELLEVUE NEWCASTLE ISSAQUAH SNOQUALMIE CARNATION NORTH BEND SEATTLE SHORELINE MEDINA BEAUX ARTS CLYDE HILL YARROW POINTHUNTS POINT LAKE FOREST PARK FEDERAL WAY PACIFIC MILTON ALGONA AUBURN KENT KENT DES MOINES BLACK DIAMOND ENUMCLAW KENT Vashon Island Maury Island COVINGTON MAPLE VALLEY 520 522 104 5 522 405 908 900 167 169 515 516 509 518 509 90 405 405 99 5 5 900 90 99 99 99 509 161 164 167 18 18 18 516 169 169 410 520 Elliott Bay LakeSamm amishLakeWashingt onP ugetSound CedarRiver G r e e n River WhiteRiver Sa mmamishRiverSnoqualmie River 0 2 4 Miles N 2-Year 24-Hour Precipitation in Inches WESTERN KING COUNTY 1. 4 1. 5 1.6 1. 7 1.8 1.9 2.0 2.02.0 2.12.22.32.42.53.0 3.5 3 . 5 3.02.92.82.72.62.1 2.12.2 2.22.32.4 Flow Control BMPs Flow control BMPs were evaluated for the Building A project site as outlined in the SWDM under Section 1.2.9.2.2 – Large Lot BMP Requirements. These BMP’s are described in order of precedence below with feasibility determined and the portion of applicable area credited as mitigated should be no less than 10% of the total site area – 1.52 acres. Flow control BMPs for the future Building B will be provided with the Building B TIR. Full Dispersion Within the proposed 15.46-acre project area, the native vegetated areas to the north (managed forest buffer) and to the west are above the proposed development. The native vegetated areas to the east (managed forest buffer) and south that are lower than the proposed development (with a minimum flowpath of 100 feet in length) contain wetlands and associated buffers. Therefore, Full Dispersion (specified in Section C.2.1.1 – minimum design requirements 3 and 5) cannot be met; hence, Full Dispersion is infeasible for this project site. Full Infiltration The Geotechnical Engineering Services Report states that “…there is very limited infiltration potential at this site. Because of these factors we recommend that stormwater detention be used for site development.” Therefore, Full Infiltration (specified in Section C.2.2.2.1) minimum requirements cannot be met; hence, Full Infiltration is infeasible for this project site. Limited Infiltration Limited Infiltration (specified in Section C.2.3) has the minimum design requirements for are the same as those for Full Infiltration. Since Full Infiltration has been deemed infeasible, Limited Infiltration is also infeasible for this project site. Bioretention According to the geotechnical memo (included in Appendix C of this report), there is insufficient infiltration onsite to facilitate a 24-hour maximum draw-down time per C.2.6.1.4; therefore, Bioretention (specified in Section C.2.6) is infeasible for this project site. Permeable Pavement This project site is defined as a “high-use site”; therefore, according to Section C.2.7 (criterion 27) of the Permeable Pavement Infeasibility Criteria List, Permeable Pavement is infeasible for this project. Basic Dispersion As discussed above for Full Dispersion, the native vegetated areas to the north (managed forest buffer) and to the west are above the proposed development. The native vegetated areas to the east (managed forest buffer) and south that are lower than the proposed development (contain wetlands and associated buffers). Basic Dispersion (specified in Section C.2.4) has been evaluated for the small impervious areas above the managed forest buffer to the east and there is insufficient vegetated flow path with acceptable length and slope for this BMP; therefore, Basic Dispersion is not feasible for this project site. If the impervious area credited as mitigated is less than the threshold specified in Flow Control BMPs above, then (according to Section 1.2.9.2.2.5 of the SWDM) a fee in lieu must be paid OR one or more the following BMPs must be implemented to achieve compliance: Reduced Impervious Surface Credit This project is larger than 250,000 square feet (Section C.2.9.2), cannot use wheel strip driveways (Section C.2.9.3) due to the proposed parking layout, cannot implement a minimum disturbance foundation (Section C.2.9.4) due to the building type, and open grid decking over pervious surface (Section C.2.9.5) is not applicable. Therefore, minimum design requirement #1 (specified in Section C.2.9.1) cannot be met; hence, the Reduced Impervious Surface Credit cannot be claimed for the proposed site improvements. Native Growth Retention Credit The minimum design requirement that any area of target impervious surface credited as mitigated by this credit must be directed to vegetated pervious areas on the site or discharged through a perforated pipe connection in accordance with Section C.2.11. While it is not feasible to direct stormwater runoff to those surfaces due to the elevation difference of the applicable vegetated pervious areas, the perforated pipe connection will be provided to the roof downspouts. The Building A onsite forest buffer area is 1.67 acres and undisturbed native vegetation area is 3.25 acres. The total 4.17 acres native vegetated area mitigates for 1.17 acres of impervious area which is equivalent to 10.8 percent of the total Building A impervious area. The native vegetated area used for this credit requires specific covenants, per SWDM, and these requirements have been compared with the Weyerhaeuser Company Concomitant Pre-Annexation Zoning Agreement (CZA). The requirements in the SWDM appear to not conflict with the CZA; therefore, native growth retention credit will be applied with area from the managed forest buffer within project site. Soil Amendment Minimum Requirement #6 All new pervious surfaces will be amended per Section 1.2.9.2.2.6 of the SWDM to satisfy the requirements specified therein (notes have been added to the final landscape plans). Roof Downspout Minimum Requirement #7 All roof downspouts are shown on the final construction plans to connect to the storm system via Perforated Pipe Connection (as specified in Section C.2.11 of the SWDM). In summary, if the impervious area credited as mitigated is not sufficient with the Native Growth Retention Credit implemented as noted above, a fee in lieu will be paid. The project will also amend soils and use perforated pipe connections for downspouts. 5. Conveyance System Analysis and Design Onsite Conveyance System: Runoff from the developed project site will be collected from the developed lawn, roof, and sidewalks by the conveyance system located around the building. The proposed stormwater drainage system is composed of catch basin structures with connecting pipes that drain to the detention pond. A conveyance and backwater analysis has been completed to verify the capacity of the critical pipes in the system. In accordance with the SWDM, the proposed stormwater drainage system has been designed to convey the 25-year peak flow rate generated by the developed tributary basin and contain the 100-year peak flow within the catch basins without any conveyance or backwater issues. Detailed conveyance calculations are provided in this section of the report. The roof drains from the building are proposed to connect to the catch basins and roof drains as shown on the SD sheets of the submitted construction plans. Following the intended architectural ridgelines and slopes of the building roof, approximately half of the roof area of the building drains to 1 of the sub-basins and the remainder of the roof is piped separately to avoid mixing with stormwater that requires oil treatment (as shown on Figure 5.1 in this section of the report). The 5 sub-basins that are collected and conveyed to the stormwater pond onsite have been modeled to drain to the upper-most catch basin within a designated segment of the stormwater drainage pipe network (as a conservative estimate). The detention pond outflow pipe matches the size of the inflow pipe to maintain conveyance capacity in the unlikely event of a flow control structure failure. The resulting drainage system contains the 100-year peak flow within the catch basins with at least 0.5-feet of freeboard. Outlet Conveyance System: For the proposed Building A development, the detention pond will match the pre-developed condition and discharge pre-developed forested stormwater runoff at the Stream EA location. From this location, runoff continues into a 24-inch CMP culvert beneath the onramp of west-bound Highway 18 to rehydrate further downstream wetlands. The Stream EA cross-section is relatively wide and appears to have capacity for larger flows than the 24-inch CMP culvert, so the culvert is estimated to control the amount of stormwater runoff that can be discharged from the site. The 24-inch CMP culvert has a capacity of 44.33 cubic feet per second, using the field verified slope of 3.82% and a Manning’s n of 0.013. The total drainage basin the combined Buildings A and B detention pond creates a mitigated 100-year flow that is 1.57 cubic feet per second. Therefore, the existing 24-inch CMP culvert is estimated to has sufficient capacity to accommodate the proposed and future development. The basin area draining to the 24-inch pipe has been mapped and shown on Figure 1.2 in Section 1 of this report. The associated conveyance calculations have been provided to WSDOT for review and approval. n WEYERHAEUSER WAY S.WEYERHAEUSER WAY S.LOOP ROA D LOOP ROAD WOODBRIDGE BUILDING "A"L L CFederal Way, WA 9800333400 8th Ave S, Suite 205C O N S U L T I N G E N G I N E E R SFEDERAL WAY CAMPUS LLCWOODBRIDGE BUILDING "A"SCALE: 1" = 200' LEGEND FIGURE 5.1 Conveyance Calculation, Woodbridge Building "A" Pipe Name Pervious Area (acres) Impervious Area (acres) Total Area (acres) 25-year Total Flow (cfs) 100-year Total Flow (cfs) Pipe Diameter (in) Pipe Diameter (ft) Pipe Area (ft^2) Wet Perimeter (ft) Hydraulic Radius (ft) Slope (ft/ft) Pipe n Capacity (cfs) Velocity @25-year Capacity (ft/sec) 25 year % Capacity (cfs) 100 year % Capacity (cfs) CB #4 to Pond 0.00 0.00 0.00 4.89 5.97 24 2 3.142 6.283 0.500 0.012 0.013 24.95 7.94 20%24% CB #5 to CB #4 0.00 0.00 0.00 4.89 5.97 24 2 3.142 6.283 0.500 0.005 0.013 16.07 5.11 30%37% CB #6 to CB #5 0.00 0.00 0.00 4.89 5.97 24 2 3.142 6.283 0.500 0.005 0.013 16.22 5.16 30%37% CB #7 to CB #6 0.00 0.00 0.00 4.89 5.97 18 1.5 1.767 4.712 0.375 0.005 0.013 7.47 4.23 65%80% CB #8 to CB #7 0.00 0.00 0.00 4.89 5.97 18 1.5 1.767 4.712 0.375 0.005 0.013 7.46 4.22 66%80% CB #9 to CB #8 0.00 0.00 0.00 4.89 5.97 18 1.5 1.767 4.712 0.375 0.005 0.013 7.46 4.22 66%80% CB #10 to CB #9 0.00 0.00 0.00 4.89 5.97 18 1.5 1.767 4.712 0.375 0.005 0.013 7.49 4.24 65%80% CB #11 to CB #10 0.00 0.00 0.00 4.89 5.97 18 1.5 1.767 4.712 0.375 0.005 0.013 7.45 4.21 66%80% CB #12 to CB #11 0.00 0.00 0.00 0.10 0.12 12 1 0.785 3.142 0.250 0.075 0.013 9.79 12.47 1%1% CB #13 to CB #12 0.15 0.00 0.15 0.10 0.12 12 1 0.785 3.142 0.250 0.006 0.013 2.65 3.38 4%4% CB #14 to CB #11 0.00 0.00 0.00 1.92 2.34 12 1 0.785 3.142 0.250 0.075 0.013 9.79 12.47 20%24% CB #15 to CB #14 0.00 0.00 0.00 1.92 2.34 12 1 0.785 3.142 0.250 0.018 0.013 4.76 6.06 40%49% CB #16 to CB #15 0.00 0.00 0.00 1.92 2.34 12 1 0.785 3.142 0.250 0.003 0.013 1.82 2.32 105%128% CB #17 to CB #16 0.05 2.36 2.41 1.92 2.34 12 1 0.785 3.142 0.250 0.011 0.013 3.68 4.68 52%64% CB #18 to CB #17 0.00 0.00 0.00 0.40 0.50 12 1 0.785 3.142 0.250 0.034 0.013 6.58 8.38 6%8% CB #19 to CB #18 0.00 0.00 0.00 0.40 0.50 12 1 0.785 3.142 0.250 0.005 0.013 2.53 3.22 16%20% CB #20 to CB #19 0.26 0.55 0.81 0.40 0.50 12 1 0.785 3.142 0.250 0.005 0.013 2.53 3.22 16%20% CB #33 to CB #11 0.00 0.00 0.00 4.58 5.59 18 1.5 1.767 4.712 0.375 0.131 0.013 38.06 21.54 12%15% CB #24 to CB #33 0.00 0.00 0.00 2.87 3.52 18 1.5 1.767 4.712 0.375 0.022 0.013 15.48 8.76 19%23% CB #25 to CB #24 0.00 0.00 0.00 2.87 3.52 18 1.5 1.767 4.712 0.375 0.005 0.013 7.45 4.21 39%47% CB #26 to CB #25 0.00 0.00 0.00 2.87 3.52 18 1.5 1.767 4.712 0.375 0.005 0.013 7.53 4.26 38%47% CB #27 to CB #26 0.00 0.00 0.00 2.87 3.52 18 1.5 1.767 4.712 0.375 0.005 0.013 7.45 4.21 39%47% CB #28 to CB #27 0.00 0.00 0.00 2.87 3.52 18 1.5 1.767 4.712 0.375 0.005 0.013 7.47 4.23 38%47% CB #29 to CB #28 0.00 0.00 0.00 2.87 3.52 12 1 0.785 3.142 0.250 0.005 0.013 2.54 3.23 113%139% CB #30 to CB #29 0.00 0.00 0.00 2.87 3.52 12 1 0.785 3.142 0.250 0.005 0.013 2.53 3.22 114%139% CB #31 to CB #30 0.00 0.00 0.00 2.87 3.52 12 1 0.785 3.142 0.250 0.005 0.013 2.53 3.22 114%139% CB #32 to CB #31 1.82 4.23 6.05 2.87 3.52 12 1 0.785 3.142 0.250 0.012 0.013 3.87 4.93 74%91% CB #34 to CB #33 0.00 0.00 0.00 1.71 2.08 12 1 0.785 3.142 0.250 0.009 0.013 3.42 4.36 50%61% CB #35 to CB #34 0.00 0.00 0.00 1.59 1.94 12 1 0.785 3.142 0.250 0.005 0.013 2.53 3.22 63%77% CB #36 to CB #35 0.00 0.00 0.00 1.13 1.37 12 1 0.785 3.142 0.250 0.005 0.013 2.53 3.22 45%54% CB #37 to CB #36 0.00 0.00 0.00 0.77 0.94 12 1 0.785 3.142 0.250 0.005 0.013 2.52 3.21 31%37% CB #38 to CB #37 0.00 0.00 0.00 0.54 0.65 8 0.666667 0.349 2.094 0.167 0.007 0.013 0.98 2.81 55%67% CB #39 to CB #38 0.00 0.00 0.00 0.44 0.53 8 0.666667 0.349 2.094 0.167 0.055 0.013 2.84 8.15 15%19% CB #40 to CB #39 0.00 0.00 0.00 0.44 0.53 8 0.666667 0.349 2.094 0.167 0.009 0.013 1.15 3.29 38%46% CB #41 to CB #40 0.00 0.00 0.00 0.44 0.53 8 0.666667 0.349 2.094 0.167 0.005 0.013 0.86 2.45 51%62% CB #42 to CB #41 0.00 0.00 0.00 0.44 0.53 8 0.666667 0.349 2.094 0.167 0.005 0.013 0.86 2.45 51%62% CB #43 to CB #42 0.00 0.00 0.00 0.44 0.53 8 0.666667 0.349 2.094 0.167 0.005 0.013 0.86 2.45 51%62% CB #44 to CB #43 0.00 0.00 0.00 0.44 0.53 8 0.666667 0.349 2.094 0.167 0.005 0.013 0.86 2.45 51%62% CB #45 to CB #44 0.00 0.00 0.00 0.44 0.53 8 0.666667 0.349 2.094 0.167 0.005 0.013 0.89 2.55 49%60% \\esm8\engr\esm-jobs\1886\001\016-0015\StormReport\Documents\Calcs-210 - Conveyance Design - V2.0.4.xlsx 11:37 AM 3/20/2020 Backwater Calculation, Woodbridge Building "A" 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Pipe Name 100-year Flow (cfs) Pipe Length (ft) Pipe Diameter (in) Pipe n Pipe I.E. Out (ft) Pipe I.E. In (ft) Pipe Area (ft) 100-year Velocity (ft/s) 100-year Velocity Head (ft/s) 100-year Tailwater Elevation (ft) 100-Year Friction Loss 100-year Entrance HGL Elevation (ft) 100-year Entrance Head Loss (ft) 100-year Exit Head Loss (ft) 100-year Outlet Control Elevation (ft) 100-year Inlet Control Elevation (ft) 100-year Appr Vel Head (ft) 100-year Bend Head Loss (ft) 100-year Junction Head Loss (ft) 100-year HW Elevation (ft) Upstream CB Grate Elevation (ft) 100-year CB Grate Elev. - HW Elev. (ft) CB #45 to CB #44 0.5 50 8 0.011 400.0 400.3 0.35 1.53 0.04 400.5 0.07 400.6 0.02 0.04 400.7 400.8 0.00 0.00 0.00 400.8 404.5 3.8 CB #44 to CB #43 0.5 50 8 0.011 399.7 400.0 0.35 1.53 0.04 400.3 0.07 400.3 0.02 0.04 400.4 400.5 0.04 0.05 0.00 400.5 404.4 3.9 CB #43 to CB #42 0.5 50 8 0.011 399.5 399.7 0.35 1.53 0.04 400.0 0.07 400.1 0.02 0.04 400.2 400.3 0.04 0.05 0.00 400.3 404.3 4.0 CB #42 to CB #41 0.5 50 8 0.011 399.2 399.5 0.35 1.53 0.04 399.8 0.07 399.8 0.02 0.04 399.9 400.0 0.04 0.05 0.00 400.0 404.1 4.1 CB #41 to CB #40 0.5 98 8 0.011 398.7 399.2 0.35 1.53 0.04 399.3 0.14 399.4 0.02 0.04 399.5 399.8 0.04 0.05 0.00 399.8 404.0 4.2 CB #40 to CB #39 0.5 10 8 0.011 398.7 398.7 0.35 1.53 0.04 399.2 0.01 399.2 0.02 0.04 399.3 399.3 0.04 0.05 0.00 399.3 403.7 4.5 CB #39 to CB #38 0.5 67 8 0.011 395.0 398.7 0.35 1.53 0.04 395.5 0.09 395.6 0.02 0.04 395.7 399.2 0.04 0.05 0.00 399.2 403.7 4.5 CB #38 to CB #37 0.7 148 8 0.011 394.0 395.0 0.35 1.88 0.05 394.4 0.31 394.7 0.03 0.05 394.8 395.5 0.04 0.05 0.00 395.5 400.0 4.4 CB #37 to CB #36 0.9 150 12 0.011 392.9 393.7 0.79 1.20 0.02 393.7 0.07 393.8 0.01 0.02 393.8 394.4 0.05 0.07 0.00 394.4 399.0 4.6 CB #36 to CB #35 1.4 200 12 0.011 391.9 392.9 0.79 1.74 0.05 392.8 0.21 393.0 0.02 0.05 393.1 393.7 0.02 0.03 0.00 393.7 398.2 4.6 CB #35 to CB #34 1.9 48 12 0.011 391.7 391.9 0.79 2.47 0.09 392.6 0.10 392.7 0.05 0.09 392.9 392.8 0.05 0.06 0.00 392.8 397.2 4.4 CB #34 to CB #33 2.1 122 12 0.011 390.6 391.7 0.79 2.64 0.11 392.0 0.29 392.3 0.05 0.11 392.4 392.6 0.09 0.12 0.00 392.6 397.3 4.7 CB #32 to CB #31 3.5 46 12 0.011 399.5 400.1 0.79 4.48 0.31 403.0 0.32 403.3 0.16 0.31 403.7 401.5 0.00 0.00 0.00 403.4 405.1 1.6 CB #31 to CB #30 3.5 130 12 0.011 398.9 399.5 0.79 4.48 0.31 401.5 0.90 402.4 0.16 0.31 402.9 401.0 0.31 0.41 0.00 403.0 403.8 0.8 CB #30 to CB #29 3.5 132 12 0.011 398.2 398.9 0.79 4.48 0.31 400.0 0.91 400.9 0.16 0.31 401.4 400.3 0.31 0.41 0.00 401.5 403.1 1.6 CB #29 to CB #28 3.5 139 12 0.011 397.5 398.2 0.79 4.48 0.31 398.5 0.96 399.5 0.16 0.31 399.9 399.7 0.31 0.41 0.00 400.0 402.4 2.4 CB #25 to CB #24 3.5 232 18 0.011 394.1 395.2 1.77 1.99 0.06 395.2 0.18 395.4 0.03 0.06 395.5 396.4 0.06 0.08 0.00 396.4 399.8 3.4 CB #24 to CB #33 3.5 163 18 0.011 390.6 394.1 1.77 1.99 0.06 392.0 0.13 392.1 0.03 0.06 392.2 395.2 0.06 0.08 0.00 395.2 399.6 4.3 CB #33 to CB #11 5.6 69 18 0.011 381.5 390.6 1.77 3.17 0.16 387.3 0.14 387.5 0.08 0.16 387.7 391.9 0.11 0.14 0.12 392.0 399.1 7.1 CB #20 to CB #19 0.5 160 12 0.011 398.5 399.3 0.79 0.63 0.01 399.2 0.02 399.2 0.00 0.01 399.2 400.0 0.00 0.00 0.00 400.0 403.3 3.3 CB #19 to CB #18 0.5 68 12 0.011 398.2 398.5 0.79 0.63 0.01 398.8 0.01 398.8 0.00 0.01 398.8 399.2 0.01 0.01 0.00 399.2 403.0 3.8 CB #18 to CB #17 0.5 117 12 0.011 394.2 398.2 0.79 0.63 0.01 395.1 0.02 395.1 0.00 0.01 395.1 398.8 0.01 0.01 0.00 398.8 403.2 4.3 CB #17 to CB #16 2.3 151 12 0.011 392.6 394.2 0.79 2.98 0.14 393.5 0.46 393.9 0.07 0.14 394.2 395.2 0.01 0.01 0.00 395.1 398.4 3.3 CB #16 to CB #15 2.3 208 12 0.011 391.6 392.1 0.79 2.98 0.14 392.6 0.64 393.2 0.07 0.14 393.4 393.1 0.14 0.18 0.00 393.5 397.6 4.1 CB #15 to CB #14 2.3 231 12 0.011 387.5 391.6 0.79 2.98 0.14 388.0 0.71 388.7 0.07 0.14 388.9 392.6 0.14 0.18 0.00 392.6 396.6 3.9 CB #14 to CB #11 2.3 72 12 0.011 381.5 387.0 0.79 2.98 0.14 387.3 0.22 387.6 0.07 0.14 387.8 387.9 0.14 0.18 0.00 388.0 395.2 7.2 CB #13 to CB #12 0.1 29 12 0.011 386.5 386.6 0.79 0.15 0.00 387.6 0.00 387.6 0.00 0.00 387.6 387.3 0.00 0.00 0.00 387.6 391.4 3.8 CB #12 to CB #11 0.1 72 12 0.011 381.5 387.0 0.79 0.15 0.00 387.3 0.00 387.3 0.00 0.00 387.3 387.6 0.00 0.00 0.00 387.6 391.5 3.9 CB #11 to CB #10 6.0 82 18 0.011 381.1 381.5 1.77 3.38 0.18 386.8 0.19 387.0 0.09 0.18 387.3 383.0 0.14 0.18 0.05 387.3 395.3 8.0 CB #10 to CB #9 6.0 81 18 0.011 380.7 381.1 1.77 3.38 0.18 386.3 0.19 386.5 0.09 0.18 386.8 382.6 0.18 0.23 0.00 386.8 391.0 4.2 CB #9 to CB #8 6.0 285 18 0.011 379.3 380.7 1.77 3.38 0.18 385.3 0.65 386.0 0.09 0.18 386.3 382.2 0.18 0.23 0.00 386.3 391.0 4.7 CB #8 to CB #7 6.0 285 18 0.011 377.9 379.3 1.77 3.38 0.18 384.4 0.65 385.0 0.09 0.18 385.3 380.7 0.18 0.23 0.00 385.3 390.0 4.6 CB #7 to CB #6 6.0 169 18 0.011 377.0 377.9 1.77 3.38 0.18 383.7 0.39 384.1 0.09 0.18 384.3 379.3 0.18 0.23 0.00 384.4 388.6 4.3 CB #6 to CB #5 6.0 45 24 0.011 376.3 376.5 3.14 1.90 0.06 383.4 0.02 383.4 0.03 0.06 383.5 378.0 0.18 0.23 0.00 383.7 387.4 3.8 CB #5 to CB #4 6.0 305 24 0.011 374.8 376.3 3.14 1.90 0.06 383.1 0.15 383.3 0.03 0.06 383.4 377.8 0.06 0.07 0.00 383.4 387.5 4.2 CB #4 to Pond 6.0 62 24 0.011 374.0 374.8 3.14 1.90 0.06 383.0 0.03 383.0 0.03 0.06 383.1 376.2 0.06 0.07 0.00 383.1 390.7 7.5 \\esm8\engr\esm-jobs\1886\001\016-0015\StormReport\Documents\Calcs-210 - Conveyance Design - V2.0.4.xlsx 11:37 AM 3/20/2020 WWHM2012 PROJECT REPORT WWHM Flows 3/12/2020 8:27:54 AM Page 2 General Model Information Project Name:WWHM Flows Site Name:Woodbridge Site - Conveyance Flows Site Address: City: Report Date:3/12/2020 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:0.000 (adjusted) Version Date:2019/09/13 Version:4.2.17 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year Low Flow Threshold for POC3:50 Percent of the 2 Year High Flow Threshold for POC3:50 Year Low Flow Threshold for POC4:50 Percent of the 2 Year High Flow Threshold for POC4:50 Year Low Flow Threshold for POC5:50 Percent of the 2 Year High Flow Threshold for POC5:50 Year Low Flow Threshold for POC11:50 Percent of the 2 Year High Flow Threshold for POC11:50 Year Low Flow Threshold for POC12:50 Percent of the 2 Year High Flow Threshold for POC12:50 Year Low Flow Threshold for POC13:50 Percent of the 2 Year High Flow Threshold for POC13:50 Year Low Flow Threshold for POC16:50 Percent of the 2 Year High Flow Threshold for POC16:50 Year WWHM Flows 3/12/2020 8:27:54 AM Page 4 Landuse Basin Data Predeveloped Land Use Sub-basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.92 C, Lawn, Flat 0.9 Pervious Total 1.82 Impervious Land Use acre ROADS FLAT 1.69 ROOF TOPS FLAT 2.54 Impervious Total 4.23 Basin Total 6.05 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 5 Sub-basin 2 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.25 Pervious Total 0.25 Impervious Land Use acre ROADS FLAT 0.56 Impervious Total 0.56 Basin Total 0.81 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 6 Sub-basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.05 Pervious Total 0.05 Impervious Land Use acre ROADS FLAT 2.36 Impervious Total 2.36 Basin Total 2.41 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 7 Sub-basin 4 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.15 Impervious Total 0.15 Basin Total 0.15 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 8 Sub-basin 5 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 2.65 Impervious Total 2.65 Basin Total 2.65 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 9 Roof Segment 1 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.689611 Impervious Total 0.689611 Basin Total 0.689611 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 10 Roof Segment 2 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.154954 Impervious Total 0.154954 Basin Total 0.154954 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 11 Roof Segment 3 (x 9) Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.18365 Impervious Total 0.18365 Basin Total 0.18365 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 12 Roof Segment 6 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.17923 Impervious Total 0.17923 Basin Total 0.17923 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 13 Mitigated Land Use Sub-basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.92 C, Lawn, Flat 0.9 Pervious Total 1.82 Impervious Land Use acre ROADS FLAT 1.69 ROOF TOPS FLAT 2.54 Impervious Total 4.23 Basin Total 6.05 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 14 Sub-basin 2 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.25 Pervious Total 0.25 Impervious Land Use acre ROADS FLAT 0.56 Impervious Total 0.56 Basin Total 0.81 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 15 Sub-basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.05 Pervious Total 0.05 Impervious Land Use acre ROADS FLAT 2.36 Impervious Total 2.36 Basin Total 2.41 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 16 Sub-basin 4 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.15 Impervious Total 0.15 Basin Total 0.15 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 17 Sub-basin 5 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 2.65 Impervious Total 2.65 Basin Total 2.65 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 18 Roof Segment 1 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.689611 Impervious Total 0.689611 Basin Total 0.689611 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 19 Roof Segment 2 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.154954 Impervious Total 0.154954 Basin Total 0.154954 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 20 Roof Segment 3 (x 9) Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.18365 Impervious Total 0.18365 Basin Total 0.18365 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 21 Roof Segment 6 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.17923 Impervious Total 0.17923 Basin Total 0.17923 Element Flows To: Surface Interflow Groundwater WWHM Flows 3/12/2020 8:27:54 AM Page 24 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:1.82 Total Impervious Area:4.23 Mitigated Landuse Totals for POC #1 Total Pervious Area:1.82 Total Impervious Area:4.23 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 1.681389 5 year 2.144214 10 year 2.460997 25 year 2.874294 50 year 3.192231 100 year 3.519187 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 1.681389 5 year 2.144214 10 year 2.460997 25 year 2.874294 50 year 3.192231 100 year 3.519187 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 2.246 2.246 1950 2.278 2.278 1951 1.417 1.417 1952 1.171 1.171 1953 1.265 1.265 1954 1.374 1.374 1955 1.531 1.531 1956 1.515 1.515 1957 1.768 1.768 1958 1.379 1.379 WWHM Flows 3/12/2020 8:30:41 AM Page 32 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area:0.25 Total Impervious Area:0.56 Mitigated Landuse Totals for POC #2 Total Pervious Area:0.25 Total Impervious Area:0.56 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 0.229525 5 year 0.296143 10 year 0.342151 25 year 0.402602 50 year 0.449394 100 year 0.497748 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 0.229525 5 year 0.296143 10 year 0.342151 25 year 0.402602 50 year 0.449394 100 year 0.497748 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 0.313 0.313 1950 0.305 0.305 1951 0.195 0.195 1952 0.156 0.156 1953 0.169 0.169 1954 0.187 0.187 1955 0.208 0.208 1956 0.206 0.206 1957 0.244 0.244 1958 0.186 0.186 1959 0.181 0.181 WWHM Flows 3/12/2020 8:31:13 AM Page 40 POC 3 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #3 Total Pervious Area:0.05 Total Impervious Area:2.36 Mitigated Landuse Totals for POC #3 Total Pervious Area:0.05 Total Impervious Area:2.36 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #3 Return Period Flow(cfs) 2 year 0.903013 5 year 1.141654 10 year 1.303908 25 year 1.514492 50 year 1.675745 100 year 1.840977 Flow Frequency Return Periods for Mitigated. POC #3 Return Period Flow(cfs) 2 year 0.903013 5 year 1.141654 10 year 1.303908 25 year 1.514492 50 year 1.675745 100 year 1.840977 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #3 Year Predeveloped Mitigated 1949 1.173 1.173 1950 1.260 1.260 1951 0.732 0.732 1952 0.648 0.648 1953 0.700 0.700 1954 0.734 0.734 1955 0.832 0.832 1956 0.819 0.819 1957 0.931 0.931 1958 0.749 0.749 1959 0.762 0.762 WWHM Flows 3/12/2020 8:31:44 AM Page 48 POC 4 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #4 Total Pervious Area:0 Total Impervious Area:0.15 Mitigated Landuse Totals for POC #4 Total Pervious Area:0 Total Impervious Area:0.15 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #4 Return Period Flow(cfs) 2 year 0.05719 5 year 0.072237 10 year 0.082461 25 year 0.095723 50 year 0.105873 100 year 0.11627 Flow Frequency Return Periods for Mitigated. POC #4 Return Period Flow(cfs) 2 year 0.05719 5 year 0.072237 10 year 0.082461 25 year 0.095723 50 year 0.105873 100 year 0.11627 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #4 Year Predeveloped Mitigated 1949 0.074 0.074 1950 0.080 0.080 1951 0.046 0.046 1952 0.041 0.041 1953 0.044 0.044 1954 0.047 0.047 1955 0.053 0.053 1956 0.052 0.052 1957 0.059 0.059 1958 0.047 0.047 1959 0.048 0.048 WWHM Flows 3/12/2020 8:32:14 AM Page 56 POC 5 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #5 Total Pervious Area:0 Total Impervious Area:2.65 Mitigated Landuse Totals for POC #5 Total Pervious Area:0 Total Impervious Area:2.65 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #5 Return Period Flow(cfs) 2 year 1.010351 5 year 1.276191 10 year 1.456811 25 year 1.691101 50 year 1.87042 100 year 2.054094 Flow Frequency Return Periods for Mitigated. POC #5 Return Period Flow(cfs) 2 year 1.010351 5 year 1.276191 10 year 1.456811 25 year 1.691101 50 year 1.87042 100 year 2.054094 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #5 Year Predeveloped Mitigated 1949 1.309 1.309 1950 1.414 1.414 1951 0.817 0.817 1952 0.727 0.727 1953 0.785 0.785 1954 0.822 0.822 1955 0.932 0.932 1956 0.917 0.917 1957 1.040 1.040 1958 0.839 0.839 1959 0.856 0.856 WWHM Flows 3/12/2020 8:32:41 AM Page 69 POC 11 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #11 Total Pervious Area:0 Total Impervious Area:0.689611 Mitigated Landuse Totals for POC #11 Total Pervious Area:0 Total Impervious Area:0.689611 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #11 Return Period Flow(cfs) 2 year 0.262924 5 year 0.332104 10 year 0.379107 25 year 0.440076 50 year 0.48674 100 year 0.534538 Flow Frequency Return Periods for Mitigated. POC #11 Return Period Flow(cfs) 2 year 0.262924 5 year 0.332104 10 year 0.379107 25 year 0.440076 50 year 0.48674 100 year 0.534538 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #11 Year Predeveloped Mitigated 1949 0.341 0.341 1950 0.368 0.368 1951 0.213 0.213 1952 0.189 0.189 1953 0.204 0.204 1954 0.214 0.214 1955 0.242 0.242 1956 0.239 0.239 1957 0.271 0.271 1958 0.218 0.218 1959 0.223 0.223 WWHM Flows 3/12/2020 8:33:08 AM Page 77 POC 12 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #12 Total Pervious Area:0 Total Impervious Area:0.154954 Mitigated Landuse Totals for POC #12 Total Pervious Area:0 Total Impervious Area:0.154954 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #12 Return Period Flow(cfs) 2 year 0.059078 5 year 0.074623 10 year 0.085184 25 year 0.098884 50 year 0.10937 100 year 0.12011 Flow Frequency Return Periods for Mitigated. POC #12 Return Period Flow(cfs) 2 year 0.059078 5 year 0.074623 10 year 0.085184 25 year 0.098884 50 year 0.10937 100 year 0.12011 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #12 Year Predeveloped Mitigated 1949 0.077 0.077 1950 0.083 0.083 1951 0.048 0.048 1952 0.043 0.043 1953 0.046 0.046 1954 0.048 0.048 1955 0.054 0.054 1956 0.054 0.054 1957 0.061 0.061 1958 0.049 0.049 1959 0.050 0.050 WWHM Flows 3/12/2020 8:33:38 AM Page 85 POC 13 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #13 Total Pervious Area:0 Total Impervious Area:0.18365 Mitigated Landuse Totals for POC #13 Total Pervious Area:0 Total Impervious Area:0.18365 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #13 Return Period Flow(cfs) 2 year 0.070019 5 year 0.088442 10 year 0.10096 25 year 0.117196 50 year 0.129624 100 year 0.142353 Flow Frequency Return Periods for Mitigated. POC #13 Return Period Flow(cfs) 2 year 0.070019 5 year 0.088442 10 year 0.10096 25 year 0.117196 50 year 0.129624 100 year 0.142353 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #13 Year Predeveloped Mitigated 1949 0.091 0.091 1950 0.098 0.098 1951 0.057 0.057 1952 0.050 0.050 1953 0.054 0.054 1954 0.057 0.057 1955 0.065 0.065 1956 0.064 0.064 1957 0.072 0.072 1958 0.058 0.058 1959 0.059 0.059 WWHM Flows 3/12/2020 8:34:07 AM Page 95 POC 16 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #16 Total Pervious Area:0 Total Impervious Area:0.17923 Mitigated Landuse Totals for POC #16 Total Pervious Area:0 Total Impervious Area:0.17923 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #16 Return Period Flow(cfs) 2 year 0.068334 5 year 0.086314 10 year 0.09853 25 year 0.114376 50 year 0.126504 100 year 0.138927 Flow Frequency Return Periods for Mitigated. POC #16 Return Period Flow(cfs) 2 year 0.068334 5 year 0.086314 10 year 0.09853 25 year 0.114376 50 year 0.126504 100 year 0.138927 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #16 Year Predeveloped Mitigated 1949 0.089 0.089 1950 0.096 0.096 1951 0.055 0.055 1952 0.049 0.049 1953 0.053 0.053 1954 0.056 0.056 1955 0.063 0.063 1956 0.062 0.062 1957 0.070 0.070 1958 0.057 0.057 1959 0.058 0.058 WWHM Flows 3/12/2020 8:34:36 AM Page 104 Appendix Predeveloped Schematic WWHM Flows 3/12/2020 8:34:37 AM Page 105 Mitigated Schematic WWHM Flows 3/12/2020 8:34:37 AM Page 119 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2020; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com 6. Special Reports and Studies The Geotechnical Engineering Services Report by GeoEngineers dated March 9, 2017, is included in Appendix C. The Critical Areas Report revised by Talasaea Consultants on March 29, 2017 (and Revised August 25, 2020), included with this submittal under separate cover. The Geotechnical Engineering Memorandum by GeoEngineers dated April 21, 2021, is included in Appendix C. 7. Other Permits Building and NPDES permits will be required for this project, together with permits for utility connections. 8. ESC Analysis and Design The Erosion and Sedimentation Control is provided on the construction plans. Supporting calculations for the sizing of the TESC ponds are provided in this section of the report. Due to topography and the proposed site design, 2 sediment ponds will be used to collect and treat runoff from the construction area. The construction of the project site will be such that the sediment ponds will receive flows from within the limits of disturbance plus a small forested area that was estimated to drain into the finished parking lot area. Due to the nature of the land use alterations, the land use type used for the TESC calculations is Till Grass and the peak storm event selected for sizing is the 10- year unmitigated peak flow. This is reasonable because the permanent stormwater detention pond will be located downstream of the collected TESC flows and will provide additional sediment removal prior discharge from the site. Building A Temporary Erosion and Sediment Control Plan (TESCP) (Pond #1) Sediment Pond Parameters Developed Basin Maximum basin contributing area (acres)8.83 Settling Velocity (feet/second)0.00096 Sediment Storage (feet)1.5 Settling Depth, Riser Height (feet)3.5 Freeboard to Overflow (feet)1 Overflow (feet)1 Total Depth (feet)7 Orifice Area, A0 (square feet)A0 0.032 2 X {orifice Head || Riser Height} (feet)2h 7 Drawdown Time T (hours)T 24 Accereration due to gravity, g (ft/sec^2)g 32.2 Orifice Diameter, D (inches)D 2.43 Minimum Dewatering Tube Diameter (inches) 6.00 Sediment Pond Sizing Developed Basin Facility Top Elev.397 Width at Top of Sed. Stor. Length at Top of Sed. Stor. Settling Depth (feet)3.5 Impervious Contributing Area (acres) Pervious Contributing Area (acres) Total Contributing Area (acres)8.83 Developed 10 year Flow, 15-minute timesteps (cfs)1.72 Design Pond Surface Area (square feet)3583 Provided Pond Surface Area (square feet)As 3585 Table for Plans Developed Basin Bottom Width 0.0 Bottom Length 89.5 Top Width 42.0 Top Length 131.5 Length:Width 3:1 Side Slopes 3:1 Over. Elev.396.0 Top Riser Pipe Elev 395.0 Bottom Elev.390.0 Top Berm Elev.397.0 Orifice Diameter (inch)2.43 Riser Size (inch)12 Building A Temporary Erosion and Sediment Control Plan (TESCP) (Pond #2) Sediment Pond Parameters Developed Basin Maximum basin contributing area (acres)5.46 Settling Velocity (feet/second)0.00096 Sediment Storage (feet)1.5 Settling Depth, Riser Height (feet)3.5 Freeboard to Overflow (feet)1 Overflow (feet)1 Total Depth (feet)7 Orifice Area, A0 (square feet)A0 0.036 2 X {orifice Head || Riser Height} (feet)2h 7 Drawdown Time T (hours)T 24 Accereration due to gravity, g (ft/sec^2)g 32.2 Orifice Diameter, D (inches)D 2.58 Minimum Dewatering Tube Diameter (inches) 6.00 Sediment Pond Sizing Developed Basin Facility Top Elev.400 Width at Top of Sed. Stor. Length at Top of Sed. Stor. Settling Depth (feet)3.5 Impervious Contributing Area (acres) Pervious Contributing Area (acres) Total Contributing Area (acres)5.46 Developed 10 year Flow, 15-minute timesteps (cfs)1.06 Design Pond Surface Area (square feet)2208 Provided Pond Surface Area (square feet)As 4050 Table for Plans Developed Basin Bottom Width 0.0 Bottom Length 105.0 Top Width 42.0 Top Length 147.0 Length:Width 4:1 Side Slopes 3:1 Over. Elev.399.0 Top Riser Pipe Elev 398.0 Bottom Elev.393.0 Top Berm Elev.400.0 Orifice Diameter (inch)2.58 Riser Size (inch)12 WWHM2012 PROJECT REPORT General Model Information Project Name: TESC Site Name: Building A Site Address: City:Federal Way Report Date: Gage:Seatac Data Start: 1948/10/01 Data End: 2009/09/30 Timestep: 15 Minute Precip Scale: 1.000 Version Date: 2019/09/13 Version: 4.2.17 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year Low Flow Threshold for POC2: 50 Percent of the 2 Year High Flow Threshold for POC2: 50 Year Landuse Basin Data Predeveloped Land Use South Basin Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 5.46 Pervious Total 5.46 Impervious Land Use acre Impervious Total 0 Basin Total 5.46 Element Flows To:Surface Interflow Groundwater East Basin Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 8.83 Pervious Total 8.83 Impervious Land Use acre Impervious Total 0 Basin Total 8.83 Element Flows To:Surface Interflow Groundwater Mitigated Land Use South Basin Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 5.46 Pervious Total 5.46 Impervious Land Use acre Impervious Total 0 Basin Total 5.46 Element Flows To:Surface Interflow Groundwater East Basin Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 8.83 Pervious Total 8.83 Impervious Land Use acre Impervious Total 0 Basin Total 8.83 Element Flows To:Surface Interflow Groundwater Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1Total Pervious Area: 8.83Total Impervious Area: 0 Mitigated Landuse Totals for POC #1Total Pervious Area: 8.83Total Impervious Area: 0 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1Return Period Flow(cfs)2 year 0.2596095 year 0.40772710 year 0.49166725 year 0.58059550 year 0.635624100 year 0.682428 Flow Frequency Return Periods for Mitigated. POC #1Return Period Flow(cfs)2 year 0.6954925 year 1.26147210 year 1.72204725 year 2.39986650 year 2.97373100 year 3.606261 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2Total Pervious Area: 5.46Total Impervious Area: 0 Mitigated Landuse Totals for POC #2Total Pervious Area: 5.46Total Impervious Area: 0 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2Return Period Flow(cfs)2 year 0.1605295 year 0.25211610 year 0.30402125 year 0.35900950 year 0.393036100 year 0.421977 Flow Frequency Return Periods for Mitigated. POC #2Return Period Flow(cfs)2 year 0.4300555 year 0.78002610 year 1.06482125 year 1.48394850 year 1.838794100 year 2.229917 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2020; All Rights Reserved. Clear Creek Solutions, Inc.6200 Capitol Blvd. Ste FOlympia, WA. 98501Toll Free 1(866)943-0304Local (360)943-0304 www.clearcreeksolutions.com 9. Bond Quantities, Facility Summaries, and Declaration of Covenant The Bond Quantities worksheet is provided in this section of the report. Public Works Department BOND QUANTITIES WORKSHEET Project Name: Woodbridge Building "A" Date: 2/27/2020 Project No.: 1886-001-016-0015 By: Laura Bartenhagen, PE Site Address: Between Weyerhaeuser Way S and south of the roundabout at 33rd Place S. Complete the following table as it pertains to this project and return to the Public Works Department. (C) Existing Public Roadway Improvements (C) Future Public Roadway Improvements Item Uni t Unit Price Quantity Quantity Price Quantity Price EROSION/SEDIMENT CONTROL Backfill & compaction - embankment CY 6.50 $ - $ - Check dams, 4” minus rock EA 78.00 $ - 20 $ 1,560.00 Crushed surfacing, 1 ¼” minus CY 98.00 $ - $ - Ditching CY 8.00 $ - 100 $ 800.00 Excavation - bulk CY 3.00 $ - 20,700 $ 62,100.00 Fence, silt LF 2.00 $ - 7,500 $ 15,000.00 Fence, temporary (NGPE)LF 2.00 $ - $ - Hydroseeding SY 1.00 $ - 44,500 $ 44,500.00 Jute Mesh SY 2.00 $ - $ - Mulch, by hand, straw, 3” deep SY 3.00 $ - $ - Mulch, by machine, 2” deep SY 1.00 $ - $ - Piping, temporary, CPP, 6”LF 12.50 $ - $ - Piping, temporary, CPP, 8”LF 19.00 $ - $ - Piping, temporary, CPP, 12”LF 24.00 $ - $ - Plastic covering, 6mm thick, sandbagged SY 3.00 $ - 750 $ 2,250.00 Rip Rap, machine placed; slopes CY 50.00 $ - $ - Rock Construction Entrance, 50’x15’x1’EA 1,800.00 $ - $ - Rock Construction Entrance, 100’x15’x1’EA 3,600.00 $ - 2 $ 7,200.00 Sediment pond riser assembly EA 3,050.00 $ - 2 $ 6,100.00 Sediment trap, 5’ high berm LF 21.00 $ - $ - Sed. Trap, 5’ high, riprap spillway berm section LF 79.00 $ - $ - Seeding, by hand SY 1.00 $ - $ - Sodding, 1” deep, level ground SY 8.00 $ - $ - Sodding, 1” deep, sloped ground SY 9.50 $ - $ - TESC Supervisor HR 84.00 $ - 200 $ 16,800.00 Water truck, dust control HR 130.00 $ - 200 $ 26,000.00 WRITE-IN-ITEMS (Wattles, Temp Treatment Systems, etc.) $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - 0 182,310.00$ 0 182,310.00$ (A) Existing Public Roadway Improvements (B) Future Public Roadway Improvements Item Unit Unit Price Quantity Price Quantity Price GENERAL ITEMS Backfill & Compaction - embankment CY 8.00 $ - 49,600 $ 396,800.00 Backfill & Compaction - trench CY 11.00 $ - $ - Clear/Remove Brush, by hand Acre 2,363.00 $ - $ - Clearing/Grubbing/Tree Removal Acre 13,000.00 $ - 15 $ 195,000.00 Excavation - bulk CY 2.50 $ - 73,300 $ 183,250.00 Excavation - trench CY 5.00 $ - $ - Fencing, chain link, vinyl coated, 6’ high LF 18.00 $ - $ - Fencing, chain link, gate, vinyl coated, 20’EA 1,563.00 $ - $ - Fill & Compaction – common barrow CY 27.00 $ - $ - Fill & Compaction – gravel base CY 30.00 $ - $ - Fill & Compaction – screened topsoil CY 62.00 $ - $ - Grading, fine, by hand SY 2.00 $ - $ - Grading, fine, with grader SY 1.25 $ - $ - Monuments with case, 18”’ long EA 104.00 $ - $ - Sensitive Areas Sign EA 20.00 $ - $ - Pond Sign EA 100.00 $ - $ - Sodding, 1” deep, sloped ground SY 10.00 $ - $ - Topsoil Type A (imported)CY 30.00 $ - $ - Surveying, line & grade Day 850.00 $ - $ - Surveying, lot location/lines Acre 1,800.00 $ - $ - Traffic control crew (2 flaggers)HR 98.00 200 $ 19,600.00 $ - Trail, 4” chipped wood SY 9.00 $ - $ - Trail, 4” top course SY 9.50 $ - $ - Wall, retaining, concrete SF 66.00 $ - $ - Wall, rockery SF 13.00 $ - $ - WRITE-IN-ITEMS $ - $ - $ - $ - $ - $ - $ - $ - SUBTOTAL 19,600.00$ 775,050.00$ (A) Existing Public Roadway Improvements (B) Future Public Roadway Improvements Item Unit Unit Price Quantity Price Quantity Price STREET IMPROVEMENT AC Grinding, 4’ wide machine < 1000sy SY 12.00 $ - $ - AC Grinding, 4’ wide machine 1000-2000sy SY 28.00 $ - $ - ESC SUBTOTAL: 30% CONTINGENCY & MOBILIZATION (If Bonding For Erosion Control Only): ESC TOTAL (C): AC Grinding, 4’ wide machine > 2000sy SY 44.00 $ - $ - AC Removal/Disposal SY 60.00 $ - $ - Barricade, type III (Permanent)LF 55.00 $ - $ - Curb & Gutter, vertical LF 15.00 3,750 $ 56,250.00 4,250 $ 63,750.00 Curb & Gutter, demolition and disposal LF 20.00 $ - $ - Curb, extruded concrete LF 4.50 $ - $ - Sawcut, asphalt, 3” depth LF 3.50 3,750 $ 13,125.00 $ - Sawcut, concrete, per 1” depth LF 3.00 $ - $ - Sealant, asphalt LF 2.00 3,750 $ 7,500.00 $ - Shoulder, HMA (see HMA road unit price)SY $ - $ - Shoulder, gravel, 4” thick SY 11.00 $ - $ - Sidewalk, 4” thick SY 40.00 3,250 $ 130,000.00 $ - Sidewalk, 4” thick, demolition and disposal SY 36.00 $ - $ - Sidewalk, 5” thick (round-about, Cul-de-Sac)SY 45.00 $ - $ - Sidewalk, 5” thick, demolition and disposal SY 45.00 $ - $ - Sign, handicap EA 100.00 6 $ 600.00 6 $ 600.00 Sign, roadway EA 350.00 24 $ 8,400.00 6 $ 2,100.00 Striping, thermoplastic (for crosswalk)SF 3.50 1,000 $ 3,500.00 250 $ 875.00 Striping, 4” reflectorized line LF 0.40 2,500 $ 1,000.00 250 $ 100.00 WRITE-IN-ITEMS $ - $ - $ - $ - $ - $ - $ - $ - SUBTOTAL 220,375.00$ 67,425.00$ (A) Existing Public Roadway Improvements (B) Future Public Roadway Improvements Item Unit Unit Price Quantity Price Quantity Price STREET SURFACING Additional 2.5” Crushed Surfacing SY 6.00 $ - $ - HMA ½” Overlay, .15’ deep SY 14.00 $ - $ - HMA ½” Overlay, .25’ deep SY 18.00 $ - $ - HMA Road, 0.25’, 8” rock, first 2500 SY SY 28.00 $ - $ - HMA Road, 0.25’, 8” rock, over 2500 SY SY 21.00 $ - 30,000 $ 630,000.00 HMA Road, .30’, 9” rock, first 2500 SY SY 42.00 $ - $ - HMA Road, .30’, 9” rock, over 2500 SY SY 35.00 $ - $ - (A) Existing Public Roadway Improvements (B) Future Public Roadway Improvements Item Unit Unit Price Quantity Price Quantity Price HMA Road, 0.30’, 0.50’ ATB, first 2500 SY SY 33.00 $ - $ - HMA Road, 0.30’, 0.50’ ATB, over 2500 SY SY 30.00 $ - $ - HMA Road, 0.50’, 0.50’ ATB, first 2500 SY SY 45.00 $ - $ - HMA Road, 0.50’, 0.50’ ATB, over 2500 SY SY 42.00 $ - $ - HMA Road, 0.30’, 0.85’ Class E & 0.5’ CSTC SY 55.00 $ - $ - HMA ¾” or 1”, 4” depth SY 20.00 $ - $ - Gravel Road, 4” rock, first 2500 SY SY 15.00 $ - $ - Gravel Road, 4” rock, over 2500 SY SY 10.00 $ - $ - WRITE-IN-ITEMS $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - SUBTOTAL:-$ 630,000.00$ (A) Existing Public Roadway Improvements (B) Future Public Roadway Improvements Item Unit Unit Price Quantity Price Quantity Price DRAINAGE Access Road, R/D SY 26.00 $ - $ - Bollards - fixed EA 240.74 $ - $ - Bollards – removable EA 452.34 $ - $ - *(CB’s include frame and lid) Beehive EA 90.00 $ - $ - CB Type I EA 1,650.00 $ - 18 $ 29,700.00 CB Type IL EA 1,850.00 $ - $ - CB Type II, 48” Dia.EA 2,550.00 $ - 11 $ 28,050.00 for additional depth over 4’FT 650.00 $ - 72 $ 46,800.00 CB Type II, 54” Dia.EA 2,700.00 $ - $ - for additional depth over 4’FT 600.00 $ - $ - CB Type II, 60” Dia.EA 2,900.00 $ - $ - for additional depth over 4’FT 750.00 $ - $ - CB Type II, 72” Dia.EA 4,000.00 $ - $ - for additional depth over 4’FT 900.00 $ - $ - Through-curb Inlet Framework (Add)EA 550.00 $ - $ - Cleanout, PVC, 6”EA 250.00 $ - $ - Cleanout, PVC, 8”EA 300.00 $ - $ - Roof Drain, PVC, 6”LF 17.00 $ - $ - (A) Existing Public Roadway Improvements (B) Future Public Roadway Improvements Item Unit Unit Price Quantity Price Quantity Price Storm Main, ADS N-12, 8”LF 25.00 $ - $ - Storm Main, ADS N-12, 12”LF 30.00 $ - 1,200 $ 36,000.00 Storm Main, ADS N-12, 15”LF 35.00 $ - $ - Storm Main, ADS N-12, 18”LF 45.00 $ - 2,250 $ 101,250.00 Storm Main, ADS N-12, 24”LF 55.00 $ - 725 $ 39,875.00 Culvert, Concrete, 8”LF 36.00 $ - $ - Culvert, Concrete, 12”LF 43.00 $ - $ - Culvert, Concrete, 15”LF 52.00 $ - $ - Culvert, Concrete, 18”LF 55.00 $ - $ - Culvert, Concrete, 24”LF 85.00 $ - $ - Ditching CY 12.00 $ - $ - Flow Dispersal Trench (1,436 base +)LF 40.00 $ - $ - French Drain (3’ depth)LF 39.00 $ - $ - Geotextile, lain in trench, polypropylene SY 5.00 $ - $ - Mid-tank Access Riser, 48” Dia., 6’ deep EA 2,025.00 $ - $ - Pond Overflow Spillway SY 18.00 $ - $ - Restrictor/Oil Separator, 12”EA 1,500.00 $ - 1 $ 1,500.00 Restrictor/Oil Separator, 15”EA 1,550.00 $ - $ - Restrictor/Oil Separator, 18”EA 1,680.00 $ - $ - Riprap, placed CY 52.00 $ - $ - Tank End Reducer (36” diameter)EA 1,280.00 $ - $ - Trash Rack, 12”EA 320.00 $ - 2 $ 640.00 Trash Rack, 15”EA 325.00 $ - $ - Trash Rack, 18”EA 350.00 $ - $ - Trash Rack, 21”EA 375.00 $ - $ - WRITE-IN-ITEMS (Oil-water separator, Stormfilter, Filterra, etc.) $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - SUBTOTAL:-$ 283,815.00$ (A) Existing Public Roadway Improvements (B) Future Public Roadway Improvements Item Unit Unit Price Quantity Price Quantity Price UTILITY POLES & STREET LIGHTING Utility Pole(s) Relocation LS $ - $ - Street Light Poles w/Luminaires EA 10,000.00 $ - $ - Traffic Signal and Appurtenances LS $ - $ - Rectangular Rapid Flashing Beacon (RRFB)LS $ - $ - LANDSCAPING & VEGITATION Street Trees EA 500.00 $ - $ Median Landscaping LS $ - $ Right-of-Way Landscaping LS $ - $ Wetland/Bioswale Landscaping LS $ - $ WRITE-IN-ITEMS Stormwater Pond LS 4000.00 $ - 1 $ 4,000.00 SUBTOTAL:-$ $ - TOTAL:(A):239,975.00$ (B): $ 1,756,290.00 Signature: Firm Name: Telephone Number: T HE FOLLOWING INFORMATION WILL BE COMPLETED BY THE C ITY OF F EDERAL W AY P UBLIC W ORKS D EPARTMENT : Existing Public Roadway Improvements (Total A): $ Future Public Right of Way (Total B): $ Erosion/Sedimentation Control (Total C): $ Subtotal (A + B + C): $ CONTINGENCY (20%): $ TOTAL BOND AMOUNT: $ 10. Operations and Maintenance The Operations and Maintenance manual is provided in this section of the report. KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL, APPENDIX A APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WATER QUALITY FACILITIES This appendix contains the maintenance requirements for the following typical stormwater control and water quality facilities and components (ctrl/click ► to follow the link): ► No. 1 – Detention Ponds (p. A-2) ► No. 2 – Infiltration Facilities (p. A-3) ► No. 3 – Detention Tanks and Vaults (p. A-5) ► No. 4 – Control Structure/Flow Restrictor (p. A-7) ► No. 5 – Catch Basins and Manholes (p. A-9) ► No. 6 – Conveyance Pipes and Ditches (p. A-11) ► No. 7 – Debris Barriers (e.g., Trash Racks) (p. A-12) ► No. 8 – Energy Dissipaters (p. A- 13) ► No. 9 – Fencing (p. A-14) ► No. 10 – Gates/Bollards/Access Barriers (p. A-15) ► No. 11 – Grounds (Landscaping) (p. A-16) ► No. 12 – Access Roads (p. A-17) ► No. 13 – Basic Bioswale (grass) (p. A-18) ► No. 14 – Wet Bioswale (p. A-19) ► No. 15 – Filter Strip (p. A-20) ► No. 16 – Wetpond (p. A-21) ► No. 17 – Wetvault (p. A-23) ► No. 18 – Stormwater Wetland (p. A-24) ► No. 19 – Sand Filter Pond (p. A-26) ► No. 20 – Sand Filter Vault (p. A-28) ► No. 21 – Stormfilter (Cartridge Type) (p. A-30) ► No. 22 – Baffle Oil/Water Separator (p. A-32) ► No. 23 – Coalescing Plate Oil/Water Separator (p. A-33) ► No. 24 – Catch Basin Insert (p. A-34) ► No. 25 – Drywell BMP (p. A-35) ► No. 26 – Gravel Filled Infiltration Trench BMP (p. A-35) ► No. 27 – Gravel Filled Dispersion Trench BMP (p. A-36) ► No. 28 – Native Vegetated Surface / Native Vegetated Landscape BMP (p. A-37) ► No. 29 – Perforated Pipe Connections BMP (p. A-37) ► No. 30 – Permeable Pavement BMP (p. A-38) ► No. 31 – Bioretention BMP (p. A-39) ► No. 32 – RainWater Harvesting BMP (p. A- 40) ► No. 33 – Rock Pad BMP (p. A-40) ► No. 34 – Sheet Flow BMP (p. A-40) ► No. 35 – Splash Block BMP (p. A-41) ► No. 36 – Vegetated Roof BMP (p. A-42) 2016 Surface Water Design Manual – Appendix A 4/24/2016 A-1 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 1 – DETENTION PONDS Maintenance Component Defect or Problem Conditions When Maintenance Is Needed Results Expected When Maintenance Is Performed Site Trash and debris Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Top or Side Slopes of Dam, Berm or Embankment Rodent holes Any evidence of rodent holes if facility is acting as a dam or berm, or any evidence of water piping through dam or berm via rodent holes. Rodents removed or destroyed and dam or berm repaired. Tree growth Tree growth threatens integrity of slopes, does not allow maintenance access, or interferes with maintenance activity. If trees are not a threat or not interfering with access or maintenance, they do not need to be removed. Trees do not hinder facility performance or maintenance activities. Erosion Eroded damage over 2 inches deep where cause of damage is still present or where there is potential for continued erosion. Any erosion observed on a compacted slope. Slopes stabilized using appropriate erosion control measures. If erosion is occurring on compacted slope, a licensed civil engineer should be consulted to resolve source of erosion. Settlement Any part of a dam, berm or embankment that has settled 4 inches lower than the design elevation. Top or side slope restored to design dimensions. If settlement is significant, a licensed civil engineer should be consulted to determine the cause of the settlement. Storage Area Sediment accumulation Accumulated sediment that exceeds 10% of the designed pond depth. Sediment cleaned out to designed pond shape and depth; pond reseeded if necessary to control erosion. Liner damaged (If Applicable) Liner is visible or pond does not hold water as designed. Liner repaired or replaced. Inlet/Outlet Pipe. Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Emergency Overflow/Spillway Tree growth Tree growth impedes flow or threatens stability of spillway. Trees removed. Rock missing Only one layer of rock exists above native soil in area five square feet or larger or any exposure of native soil on the spillway. Spillway restored to design standards. 4/24/2016 2016 Surface Water Design Manual – Appendix A A-2 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Structure Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the structure opening or is blocking capacity of the structure by more than 10%. No Trash or debris blocking or potentially blocking entrance to structure. Trash or debris in the structure that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the structure. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Sediment Sediment exceeds 60% of the depth from the bottom of the structure to the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section or is within 6 inches of the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section. Sump of structure contains no sediment. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering structure through cracks, or maintenance person judges that structure is unsound. Structure is sealed and structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering structure through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Structure has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the structure at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Ladder rungs missing or unsafe Ladder is unsafe due to missing rungs, misalignment, rust, cracks, or sharp edges. Ladder meets design standards and allows maintenance person safe access. FROP-T Section Damage T section is not securely attached to structure wall and outlet pipe structure should support at least 1,000 lbs of up or down pressure. T section securely attached to wall and outlet pipe. Structure is not in upright position (allow up to 10% from plumb). Structure in correct position. Connections to outlet pipe are not watertight or show signs of deteriorated grout. Connections to outlet pipe are water tight; structure repaired or replaced and works as designed. Any holes—other than designed holes—in the structure. Structure has no holes other than designed holes. 2016 Surface Water Design Manual – Appendix A 4/24/2016 A-7 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Cleanout Gate Damaged or missing Cleanout gate is missing. Replace cleanout gate. Cleanout gate is not watertight. Gate is watertight and works as designed. Gate cannot be moved up and down by one maintenance person. Gate moves up and down easily and is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Orifice Plate Damaged or missing Control device is not working properly due to missing, out of place, or bent orifice plate. Plate is in place and works as designed. Obstructions Any trash, debris, sediment, or vegetation blocking the plate. Plate is free of all obstructions and works as designed. Overflow Pipe Obstructions Any trash or debris blocking (or having the potential of blocking) the overflow pipe. Pipe is free of all obstructions and works as designed. Deformed or damaged lip Lip of overflow pipe is bent or deformed. Overflow pipe does not allow overflow at an elevation lower than design Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Metal Grates (If Applicable) Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s) of the grate. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism Not Working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to Remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance person. 4/24/2016 2016 Surface Water Design Manual – Appendix A A-8 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 5 – CATCH BASINS AND MANHOLES Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Structure Sediment Sediment exceeds 60% of the depth from the bottom of the catch basin to the invert of the lowest pipe into or out of the catch basin or is within 6 inches of the invert of the lowest pipe into or out of the catch basin. Sump of catch basin contains no sediment. Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the catch basin opening or is blocking capacity of the catch basin by more than 10%. No Trash or debris blocking or potentially blocking entrance to catch basin. Trash or debris in the catch basin that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the catch basin. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). No dead animals or vegetation present within catch basin. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering catch basin through cracks, or maintenance person judges that catch basin is unsound. Catch basin is sealed and is structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Catch basin has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the catch basin at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. 2016 Surface Water Design Manual – Appendix A 4/24/2016 A-9 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 5 – CATCH BASINS AND MANHOLES Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Metal Grates (Catch Basins) Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s) of the grate. Any open structure requires urgent maintenance. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism Not Working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to Remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance person. 4/24/2016 2016 Surface Water Design Manual – Appendix A A-10 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 6 – CONVEYANCE PIPES AND DITCHES Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Pipes Sediment & debris accumulation Accumulated sediment or debris that exceeds 20% of the diameter of the pipe. Water flows freely through pipes. Vegetation/roots Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damage to protective coating or corrosion Protective coating is damaged; rust or corrosion is weakening the structural integrity of any part of pipe. Pipe repaired or replaced. Damaged Any dent that decreases the cross section area of pipe by more than 20% or is determined to have weakened structural integrity of the pipe. Pipe repaired or replaced. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 square feet of ditch and slopes. Trash and debris cleared from ditches. Sediment accumulation Accumulated sediment that exceeds 20% of the design depth. Ditch cleaned/flushed of all sediment and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Vegetation Vegetation that reduces free movement of water through ditches. Water flows freely through ditches. Erosion damage to slopes Any erosion observed on a ditch slope. Slopes are not eroding. Rock lining out of place or missing (If Applicable) One layer or less of rock exists above native soil area 5 square feet or more, any exposed native soil. Replace rocks to design standards. 2016 Surface Water Design Manual – Appendix A 4/24/2016 A-11 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 11 – GROUNDS (LANDSCAPING) Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Site Trash or litter Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Trees and Shrubs Hazard Any tree or limb of a tree identified as having a potential to fall and cause property damage or threaten human life. A hazard tree identified by a qualified arborist must be removed as soon as possible. No hazard trees in facility. Damaged Limbs or parts of trees or shrubs that are split or broken which affect more than 25% of the total foliage of the tree or shrub. Trees and shrubs with less than 5% of total foliage with split or broken limbs. Trees or shrubs that have been blown down or knocked over. No blown down vegetation or knocked over vegetation. Trees or shrubs free of injury. Trees or shrubs which are not adequately supported or are leaning over, causing exposure of the roots. Tree or shrub in place and adequately supported; dead or diseased trees removed. 4/24/2016 2016 Surface Water Design Manual – Appendix A A-16 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 21 – STORMFILTER (CARTRIDGE TYPE) Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Facility Documentation Update facility inspection record after each inspection. Maintenance records are up to date. Provide certification of replaced filter media. Filter media is certified to meet Stormfilter® specifications. Site Trash and debris Any trash or debris which impairs the function of the facility. Trash and debris removed from facility. Contaminants and pollution Any evidence of contaminants or pollution such as oils, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Life cycle System has not been inspected for three years. Facility is re-inspected and any needed maintenance performed. Vault Treatment Area Sediment on vault floor Greater than 2 inches of sediment. Vault is free of sediment. Sediment on top of cartridges Greater than ½ inch of sediment. Vault is free of sediment. Multiple scum lines above top of cartridges Thick or multiple scum lines above top of cartridges. Probably due to plugged canisters or underdrain manifold. Cause of plugging corrected, canisters replaced if necessary. Vault Structure Damage to wall, Frame, Bottom, and/or Top Slab Cracks wider than ½-inch and any evidence of soil particles entering the structure through the cracks, or qualified inspection personnel determines the vault is not structurally sound. Vault replaced or repaired to design specifications. Baffles damaged Baffles corroding, cracking warping, and/or showing signs of failure as determined by maintenance/inspection person. Repair or replace baffles to specification. Filter Media Standing water in vault 9 inches or greater of static water in the vault for more than 24 hours following a rain event and/or overflow occurs frequently. Probably due to plugged filter media, underdrain or outlet pipe. No standing water in vault 24 hours after a rain event. Short circuiting Flows do not properly enter filter cartridges. Flows go through filter media. Underdrains and Clean-Outs Sediment/debris Underdrains or clean-outs partially plugged or filled with sediment and/or debris. Underdrains and clean-outs free of sediment and debris. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Any open manhole requires immediate maintenance. Manhole access covered. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs of lift. Cover/lid can be removed and reinstalled by one maintenance person. 4/24/2016 2016 Surface Water Design Manual – Appendix A A-30 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 21 – STORMFILTER (CARTRIDGE TYPE) Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large access doors/plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can opened as designed. Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat and cover access opening completely. Lifting Rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate. Inspection Frequency Maintenance conditions are site-specific, depending on pollutant loading. FIRST YEAR POST CONSTRUCTION: Monthly during wet season, every other month during dry season FOLLOWING FIRST YEAR: Continue monthly until site-specific frequency is established, then follow that schedule AT A MINIMUM, FOLLOWING FIRST YEAR: Annually (or quarterly if used as primary treatment) and following significant storms. Inspect Stormfilter facility for any maintenance deficiencies; maintain or replace as required per established site-specific schedule and manufacturer’s requirements. 2016 Surface Water Design Manual – Appendix A 4/24/2016 A-31 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 23 – COALESCING PLATE OIL/WATER SEPARATOR Maintenance Component Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed Site Trash and debris Any trash or debris which impairs the function of the facility. Trash and debris removed from facility. Contaminants and pollution Floating oil in excess of 1 inch in first chamber, any oil in other chambers or other contaminants of any type in any chamber. No contaminants present other than a surface oil film. Vault Treatment Area Sediment accumulation in the forebay Sediment accumulation of 6 inches or greater in the forebay. No sediment in the forebay. Discharge water not clear Inspection of discharge water shows obvious signs of poor water quality - effluent discharge from vault shows thick visible sheen. Repair function of plates so effluent is clear. Trash or debris accumulation Trash and debris accumulation in vault (floatables and non-floatables). Trash and debris removed from vault. Oil accumulation Oil accumulation that exceeds 1 inch at the water surface in the in the coalescing plate chamber. No visible oil depth on water and coalescing plates clear of oil. Coalescing Plates Damaged Plate media broken, deformed, cracked and/or showing signs of failure. Replace that portion of media pack or entire plate pack depending on severity of failure. Sediment accumulation Any sediment accumulation which interferes with the operation of the coalescing plates. No sediment accumulation interfering with the coalescing plates. Vault Structure Damage to Wall, Frame, Bottom, and/or Top Slab Cracks wider than ½-inch and any evidence of soil particles entering the structure through the cracks, or maintenance inspection personnel determines that the vault is not structurally sound. Vault replaced or repaired to design specifications. Baffles damaged Baffles corroding, cracking, warping and/or showing signs of failure as determined by maintenance/inspection person. Repair or replace baffles to specifications. Ventilation Pipes Plugged Any obstruction to the ventilation pipes. Ventilation pipes are clear. Shutoff Valve Damaged or inoperable Shutoff valve cannot be opened or closed. Shutoff valve operates normally. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Any open manhole requires immediate maintenance. Manhole access covered. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs of lift. Cover/lid can be removed and reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. 2016 Surface Water Design Manual – Appendix A 4/24/2016 A-33 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 23 – COALESCING PLATE OIL/WATER SEPARATOR Maintenance Component Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed Large access doors/plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can opened as designed. Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat and cover access opening completely. Lifting Rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate. NO. 24 – CATCH BASIN INSERT Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Media Insert Visible Oil Visible oil sheen passing through media Media inset replaced. Insert does not fit catch basin properly Flow gets into catch basin without going through media. All flow goes through media. Filter media plugged Filter media plugged. Flow through filter media is normal. Oil absorbent media saturated Media oil saturated. Oil absorbent media replaced. Water saturated Catch basin insert is saturated with water, which no longer has the capacity to absorb. Insert replaced. Service life exceeded Regular interval replacement due to typical average life of media insert product, typically one month. Media replaced at manufacturer’s recommended interval. Seasonal maintenance When storms occur and during the wet season. Remove, clean and replace or install new insert after major storms, monthly during the wet season or at manufacturer’s recommended interval. 4/24/2016 2016 Surface Water Design Manual – Appendix A A-34 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 23 – COALESCING PLATE OIL/WATER SEPARATOR Maintenance Component Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed Large access doors/plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can opened as designed. Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat and cover access opening completely. Lifting Rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate. NO. 24 – CATCH BASIN INSERT Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Media Insert Visible Oil Visible oil sheen passing through media Media inset replaced. Insert does not fit catch basin properly Flow gets into catch basin without going through media. All flow goes through media. Filter media plugged Filter media plugged. Flow through filter media is normal. Oil absorbent media saturated Media oil saturated. Oil absorbent media replaced. Water saturated Catch basin insert is saturated with water, which no longer has the capacity to absorb. Insert replaced. Service life exceeded Regular interval replacement due to typical average life of media insert product, typically one month. Media replaced at manufacturer’s recommended interval. Seasonal maintenance When storms occur and during the wet season. Remove, clean and replace or install new insert after major storms, monthly during the wet season or at manufacturer’s recommended interval. 4/24/2016 2016 Surface Water Design Manual – Appendix A A-34 oldcastleprecast.com/wilsonville File Name: PO Box 323, Wilsonville, Oregon 97070-0323 Tel: (503) 682-2844 Fax: (503) 682-2657 Issue Date: 612-2-CPS 2018 020-612CPS2 612-2-CPS OIL / WATER SEPARATOR COALESCING - 420 GPM 612-2-CPS 9.0 TOP No. 612-T-CPS BASE ASSEMBLY No. 612-B-CPS 24,130 lbs. OPTIONAL TOP - HEAVY TRAFFIC No. 612-T-CPS-HD A PLAN VIEW SECTION AA A Issue Date: File Name: PO Box 323, Wilsonville, Oregon 97070-0323 Tel: (503) 682-2844 Fax: (503) 682-2657 oldcastleprecast.com/wilsonville 612-2-CPS 2018 020-612CPS2 612-2-CPS OIL / WATER SEPARATOR COALESCING - 420 GPM 612-2-CPS 9.1 www.modularwetlands.com Maintenance Guidelines for Modular Wetland System - Linear Maintenance Summary o Remove Trash from Screening Device – average maintenance interval is 6 to 12 months.  (5 minute average service time). o Remove Sediment from Separation Chamber – average maintenance interval is 12 to 24 months.  (10 minute average service time). o Replace Cartridge Filter Media – average maintenance interval 12 to 24 months.  (10-15 minute per cartridge average service time). o Replace Drain Down Filter Media – average maintenance interval is 12 to 24 months.  (5 minute average service time). o Trim Vegetation – average maintenance interval is 6 to 12 months.  (Service time varies). System Diagram Access to screening device, separation chamber and cartridge filter Access to drain down filter Pre-Treatment Chamber Biofiltration Chamber Discharge Chamber Outflow Pipe Inflow Pipe (optional) www.modularwetlands.com Maintenance Procedures Screening Device 1. Remove grate or manhole cover to gain access to the screening device in the Pre- Treatment Chamber. Vault type units do not have screening device. Maintenance can be performed without entry. 2. Remove all pollutants collected by the screening device. Removal can be done manually or with the use of a vacuum truck. The hose of the vacuum truck will not damage the screening device. 3. Screening device can easily be removed from the Pre-Treatment Chamber to gain access to separation chamber and media filters below. Replace grate or manhole cover when completed. Separation Chamber 1. Perform maintenance procedures of screening device listed above before maintaining the separation chamber. 2. With a pressure washer spray down pollutants accumulated on walls and cartridge filters. 3. Vacuum out Separation Chamber and remove all accumulated pollutants. Replace screening device, grate or manhole cover when completed. Cartridge Filters 1. Perform maintenance procedures on screening device and separation chamber before maintaining cartridge filters. 2. Enter separation chamber. 3. Unscrew the two bolts holding the lid on each cartridge filter and remove lid. 4. Remove each of 4 to 8 media cages holding the media in place. 5. Spray down the cartridge filter to remove any accumulated pollutants. 6. Vacuum out old media and accumulated pollutants. 7. Reinstall media cages and fill with new media from manufacturer or outside supplier. Manufacturer will provide specification of media and sources to purchase. 8. Replace the lid and tighten down bolts. Replace screening device, grate or manhole cover when completed. Drain Down Filter 1. Remove hatch or manhole cover over discharge chamber and enter chamber. 2. Unlock and lift drain down filter housing and remove old media block. Replace with new media block. Lower drain down filter housing and lock into place. 3. Exit chamber and replace hatch or manhole cover. www.modularwetlands.com Maintenance Notes 1. Following maintenance and/or inspection, it is recommended the maintenance operator prepare a maintenance/inspection record. The record should include any maintenance activities performed, amount and description of debris collected, and condition of the system and its various filter mechanisms. 2. The owner should keep maintenance/inspection record(s) for a minimum of five years from the date of maintenance. These records should be made available to the governing municipality for inspection upon request at any time. 3. Transport all debris, trash, organics and sediments to approved facility for disposal in accordance with local and state requirements. 4. Entry into chambers may require confined space training based on state and local regulations. 5. No fertilizer shall be used in the Biofiltration Chamber. 6. Irrigation should be provided as recommended by manufacturer and/or landscape architect. Amount of irrigation required is dependent on plant species. Some plants may require irrigation. www.modularwetlands.com Maintenance Procedure Illustration Screening Device The screening device is located directly under the manhole or grate over the Pre-Treatment Chamber. It’s mounted directly underneath for easy access and cleaning. Device can be cleaned by hand or with a vacuum truck. Separation Chamber The separation chamber is located directly beneath the screening device. It can be quickly cleaned using a vacuum truck or by hand. A pressure washer is useful to assist in the cleaning process. www.modularwetlands.com Cartridge Filters The cartridge filters are located in the Pre-Treatment chamber connected to the wall adjacent to the biofiltration chamber. The cartridges have removable tops to access the individual media filters. Once the cartridge is open media can be easily removed and replaced by hand or a vacuum truck. Drain Down Filter The drain down filter is located in the Discharge Chamber. The drain filter unlocks from the wall mount and hinges up. Remove filter block and replace with new block. www.modularwetlands.com Trim Vegetation Vegetation should be maintained in the same manner as surrounding vegetation and trimmed as needed. No fertilizer shall be used on the plants. Irrigation per the recommendation of the manufacturer and or landscape architect. Different types of vegetation requires different amounts of irrigation. www.modularwetlands.com Inspection Form Modular Wetland System, Inc. P. 760.433-7640 F. 760-433-3176 E. Info@modularwetlands.com For Office Use Only (city) (Zip Code)(Reviewed By) Owner / Management Company (Date) Contact Phone ( )_ Inspector Name Date / / Time AM / PM Weather Condition Additional Notes Yes Depth: Yes No Modular Wetland System Type (Curb, Grate or UG Vault):Size (22', 14' or etc.): Other Inspection Items: Storm Event in Last 72-hours? No Yes Type of Inspection Routine Follow Up Complaint Storm Office personnel to complete section to the left. 2972 San Luis Rey Road, Oceanside, CA 92058 P (760) 433-7640 F (760) 433-3176 Inspection Report Modular Wetlands System Is the filter insert (if applicable) at capacity and/or is there an accumulation of debris/trash on the shelf system? Does the cartridge filter media need replacement in pre-treatment chamber and/or discharge chamber? Any signs of improper functioning in the discharge chamber? Note issues in comments section. Chamber: Is the inlet/outlet pipe or drain down pipe damaged or otherwise not functioning properly? Structural Integrity: Working Condition: Is there evidence of illicit discharge or excessive oil, grease, or other automobile fluids entering and clogging the unit? Is there standing water in inappropriate areas after a dry period? Damage to pre-treatment access cover (manhole cover/grate) or cannot be opened using normal lifting pressure? Damage to discharge chamber access cover (manhole cover/grate) or cannot be opened using normal lifting pressure? Does the MWS unit show signs of structural deterioration (cracks in the wall, damage to frame)? Project Name Project Address Inspection Checklist CommentsNo Does the depth of sediment/trash/debris suggest a blockage of the inflow pipe, bypass or cartridge filter? If yes, specify which one in the comments section. Note depth of accumulation in in pre-treatment chamber. Is there a septic or foul odor coming from inside the system? Is there an accumulation of sediment/trash/debris in the wetland media (if applicable)? Is it evident that the plants are alive and healthy (if applicable)? Please note Plant Information below. Sediment / Silt / Clay Trash / Bags / Bottles Green Waste / Leaves / Foliage Waste:Plant Information No Cleaning Needed Recommended Maintenance Additional Notes: Damage to Plants Plant Replacement Plant Trimming Schedule Maintenance as Planned Needs Immediate Maintenance www.modularwetlands.com Maintenance Report Modular Wetland System, Inc. P. 760.433-7640 F. 760-433-3176 E. Info@modularwetlands.com For Office Use Only (city) (Zip Code)(Reviewed By) Owner / Management Company (Date) Contact Phone ( )_ Inspector Name Date / / Time AM / PM Weather Condition Additional Notes Site Map # Comments: 2972 San Luis Rey Road, Oceanside, CA 92058 P. 760.433.7640 F. 760.433.3176 Inlet and Outlet Pipe Condition Drain Down Pipe Condition Discharge Chamber Condition Drain Down Media Condition Plant Condition Media Filter Condition Long: MWS Sedimentation Basin Total Debris Accumulation Condition of Media 25/50/75/100 (will be changed @ 75%) Operational Per Manufactures' Specifications (If not, why?) Lat:MWS Catch Basins GPS Coordinates of Insert Manufacturer / Description / Sizing Trash Accumulation Foliage Accumulation Sediment Accumulation Type of Inspection Routine Follow Up Complaint Storm Storm Event in Last 72-hours? No Yes Office personnel to complete section to the left. Project Address Project Name Cleaning and Maintenance Report Modular Wetlands System STANDARD DETAIL STORMWATER BIOFILTRATION SYSTEM MWS-L-8-12-V PLAN VIEW ELEVATION VIEW RIGHT END VIEW LEFT END VIEW GENERAL NOTES INSTALLATION NOTES SITE SPECIFIC DATA Appendix A n WEYERHAEUSER WAY S.WEYERHAEUSER WAY S.LOOP ROA D LOOP ROAD WOODBRIDGE BUILDING "A"L L CFederal Way, WA 9800333400 8th Ave S, Suite 205C O N S U L T I N G E N G I N E E R SFEDERAL WAY CAMPUS LLCWOODBRIDGE BUILDING "A"SCALE: 1" = 200' LEGEND Appendix B WWHM2012 PROJECT REPORT Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 2 General Model Information Project Name:Woodbridge Bldg A Site Name:Woodbridge Building A - Detention & WQ Site Address: City:Federal Way Report Date:3/5/2020 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:0.000 (adjusted) Version Date:2019/09/13 Version:4.2.17 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year Low Flow Threshold for POC3:50 Percent of the 2 Year High Flow Threshold for POC3:50 Year Low Flow Threshold for POC4:50 Percent of the 2 Year High Flow Threshold for POC4:50 Year Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 3 Landuse Basin Data Predeveloped Land Use PreDev - Building A - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 12.07 Pervious Total 12.07 Impervious Land Use acre Impervious Total 0 Basin Total 12.07 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 4 PreDev - Building A - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.14 Pervious Total 0.14 Impervious Land Use acre Impervious Total 0 Basin Total 0.14 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 5 PreDev - Building A ROW - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.02 Pervious Total 0.02 Impervious Land Use acre Impervious Total 0 Basin Total 0.02 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 6 PreDev - Building A ROW - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.28 Pervious Total 0.28 Impervious Land Use acre Impervious Total 0 Basin Total 0.28 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 7 PreDev - Building B Parcel Improvments - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 2.39 Pervious Total 2.39 Impervious Land Use acre Impervious Total 0 Basin Total 2.39 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 8 PreDev - Building A - Oil/Water Sep - Sub-basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.05 Pervious Total 0.05 Impervious Land Use acre ROADS FLAT 2.36 Impervious Total 2.36 Basin Total 2.41 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 9 PreDev - Building A ROW - Un-Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.48 Pervious Total 0.48 Impervious Land Use acre Impervious Total 0 Basin Total 0.48 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 10 Water Quality POC Node Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 1 Pervious Total 1 Impervious Land Use acre Impervious Total 0 Basin Total 1 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 11 Mitigated Land Use Dev - Building B Parcel Improvments - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.96 Pervious Total 1.96 Impervious Land Use acre ROADS FLAT 0.43 Impervious Total 0.43 Basin Total 2.39 Element Flows To: Surface Interflow Groundwater Detention Pond - 2:1 Side SlopesDetention Pond - 2:1 Side Slopes Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 12 Dev - Building A - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.2 C, Forest, Flat 0.92 Pervious Total 2.12 Impervious Land Use acre ROADS FLAT 4.76 ROOF TOPS FLAT 5.19 Impervious Total 9.95 Basin Total 12.07 Element Flows To: Surface Interflow Groundwater Detention Pond - 2:1 Side SlopesDetention Pond - 2:1 Side Slopes Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 13 Dev - Building A ROW - Detained Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.02 Impervious Total 0.02 Basin Total 0.02 Element Flows To: Surface Interflow Groundwater Detention Pond - 2:1 Side SlopesDetention Pond - 2:1 Side Slopes Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 14 Dev - Building A ROW - Bypass Bypass:Yes GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.28 Impervious Total 0.28 Basin Total 0.28 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 15 Dev - Building A - Bypass Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.07 Pervious Total 0.07 Impervious Land Use acre ROADS FLAT 0.07 Impervious Total 0.07 Basin Total 0.14 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 16 Dev - Building A - Oil/Water Sep - Sub-basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.05 Pervious Total 0.05 Impervious Land Use acre ROADS FLAT 2.36 Impervious Total 2.36 Basin Total 2.41 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 17 Dev - Building A ROW - Un-Detained Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre SIDEWALKS FLAT 0.48 Impervious Total 0.48 Basin Total 0.48 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 19 Mitigated Routing Detention Pond - 2:1 Side Slopes Bottom Length:180.00 ft. Bottom Width:135.00 ft. Depth:9 ft. Volume at riser head:5.1288 acre-feet. Side slope 1:2 To 1 Side slope 2:2 To 1 Side slope 3:2 To 1 Side slope 4:2 To 1 Discharge Structure Riser Height:7.5 ft. Riser Diameter:24 in. Notch Type:Rectangular Notch Width:0.021 ft. Notch Height:1.500 ft. Orifice 1 Diameter:1.95 in.Elevation:0 ft. Orifice 2 Diameter:2.25 in.Elevation:4.25 ft. Orifice 3 Diameter:2.25 in.Elevation:5.25 ft. Element Flows To: Outlet 1 Outlet 2 POC 1 Analysis Node Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 374.50 0.557 0.000 0.000 0.000 374.60 0.560 0.055 0.032 0.000 374.70 0.563 0.112 0.046 0.000 374.80 0.566 0.168 0.056 0.000 374.90 0.569 0.225 0.065 0.000 375.00 0.572 0.282 0.073 0.000 375.10 0.575 0.339 0.079 0.000 375.20 0.578 0.397 0.086 0.000 375.30 0.581 0.455 0.092 0.000 375.40 0.584 0.513 0.097 0.000 375.50 0.587 0.572 0.103 0.000 375.60 0.590 0.631 0.108 0.000 375.70 0.593 0.690 0.113 0.000 375.80 0.596 0.749 0.117 0.000 375.90 0.599 0.809 0.122 0.000 376.00 0.602 0.869 0.126 0.000 376.10 0.605 0.930 0.130 0.000 376.20 0.608 0.990 0.134 0.000 376.30 0.611 1.051 0.138 0.000 376.40 0.614 1.113 0.142 0.000 376.50 0.617 1.174 0.145 0.000 376.60 0.620 1.236 0.149 0.000 376.70 0.623 1.298 0.153 0.000 376.80 0.626 1.361 0.156 0.000 376.90 0.629 1.423 0.159 0.000 377.00 0.632 1.486 0.163 0.000 377.10 0.635 1.550 0.166 0.000 377.20 0.638 1.614 0.169 0.000 377.30 0.641 1.678 0.172 0.000 377.40 0.644 1.742 0.175 0.000 Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 20 377.50 0.647 1.807 0.178 0.000 377.60 0.651 1.872 0.181 0.000 377.70 0.654 1.937 0.184 0.000 377.80 0.657 2.002 0.187 0.000 377.90 0.660 2.068 0.190 0.000 378.00 0.663 2.134 0.193 0.000 378.10 0.666 2.201 0.195 0.000 378.20 0.669 2.268 0.198 0.000 378.30 0.673 2.335 0.201 0.000 378.40 0.676 2.402 0.203 0.000 378.50 0.679 2.470 0.206 0.000 378.60 0.682 2.538 0.208 0.000 378.70 0.685 2.607 0.211 0.000 378.80 0.689 2.675 0.244 0.000 378.90 0.692 2.745 0.269 0.000 379.00 0.695 2.814 0.287 0.000 379.10 0.698 2.884 0.302 0.000 379.20 0.701 2.954 0.315 0.000 379.30 0.705 3.024 0.328 0.000 379.40 0.708 3.095 0.339 0.000 379.50 0.711 3.166 0.349 0.000 379.60 0.714 3.237 0.359 0.000 379.70 0.718 3.309 0.369 0.000 379.80 0.721 3.381 0.409 0.000 379.90 0.724 3.453 0.440 0.000 380.00 0.728 3.526 0.464 0.000 380.10 0.731 3.599 0.485 0.000 380.20 0.734 3.672 0.503 0.000 380.30 0.738 3.746 0.521 0.000 380.40 0.741 3.819 0.537 0.000 380.50 0.744 3.894 0.553 0.000 380.60 0.748 3.968 0.570 0.000 380.70 0.751 4.043 0.588 0.000 380.80 0.754 4.119 0.607 0.000 380.90 0.758 4.194 0.626 0.000 381.00 0.761 4.270 0.644 0.000 381.10 0.764 4.347 0.663 0.000 381.20 0.768 4.423 0.682 0.000 381.30 0.771 4.500 0.701 0.000 381.40 0.774 4.578 0.719 0.000 381.50 0.778 4.655 0.738 0.000 381.60 0.781 4.733 0.757 0.000 381.70 0.785 4.812 0.777 0.000 381.80 0.788 4.890 0.797 0.000 381.90 0.792 4.969 0.817 0.000 382.00 0.795 5.049 0.870 0.000 382.10 0.798 5.128 1.551 0.000 382.20 0.802 5.208 2.777 0.000 382.30 0.805 5.289 4.322 0.000 382.40 0.809 5.370 6.045 0.000 382.50 0.812 5.451 7.807 0.000 382.60 0.816 5.532 9.469 0.000 382.70 0.819 5.614 10.90 0.000 382.80 0.823 5.696 12.03 0.000 382.90 0.826 5.779 12.84 0.000 383.00 0.830 5.861 13.43 0.000 383.10 0.833 5.945 14.18 0.000 383.20 0.837 6.028 14.78 0.000 Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 21 383.30 0.840 6.112 15.35 0.000 383.40 0.844 6.196 15.90 0.000 383.50 0.847 6.281 16.44 0.000 383.60 0.851 6.366 16.95 0.000 Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 22 POC 1 Analysis Node Bottom Length:10.00 ft. Bottom Width:10.00 ft. Manning's n:0.03 Channel bottom slope 1:0.05 To 1 Channel Left side slope 0:0 To 1 Channel right side slope 2:0 To 1 Discharge Structure Riser Height:0 ft. Riser Diameter:0 in. Element Flows To: Outlet 1 Outlet 2 Channel Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.002 0.000 0.000 0.000 0.0556 0.002 0.000 0.891 0.000 0.1111 0.002 0.000 2.810 0.000 0.1667 0.002 0.000 5.484 0.000 0.2222 0.002 0.000 8.795 0.000 0.2778 0.002 0.000 12.66 0.000 0.3333 0.002 0.000 17.04 0.000 0.3889 0.002 0.000 21.89 0.000 0.4444 0.002 0.001 27.16 0.000 0.5000 0.002 0.001 32.82 0.000 0.5556 0.002 0.001 38.86 0.000 0.6111 0.002 0.001 45.25 0.000 0.6667 0.002 0.001 51.97 0.000 0.7222 0.002 0.001 59.01 0.000 0.7778 0.002 0.001 66.34 0.000 0.8333 0.002 0.001 73.95 0.000 0.8889 0.002 0.002 81.83 0.000 0.9444 0.002 0.002 89.96 0.000 1.0000 0.002 0.002 98.34 0.000 1.0556 0.002 0.002 106.9 0.000 1.1111 0.002 0.002 115.8 0.000 1.1667 0.002 0.002 124.8 0.000 1.2222 0.002 0.002 134.1 0.000 1.2778 0.002 0.003 143.5 0.000 1.3333 0.002 0.003 153.2 0.000 1.3889 0.002 0.003 163.0 0.000 1.4444 0.002 0.003 173.0 0.000 1.5000 0.002 0.003 183.2 0.000 1.5556 0.002 0.003 193.6 0.000 1.6111 0.002 0.003 204.1 0.000 1.6667 0.002 0.003 214.7 0.000 1.7222 0.002 0.004 225.6 0.000 1.7778 0.002 0.004 236.5 0.000 1.8333 0.002 0.004 247.6 0.000 1.8889 0.002 0.004 258.8 0.000 1.9444 0.002 0.004 270.2 0.000 2.0000 0.002 0.004 281.7 0.000 2.0556 0.002 0.004 293.3 0.000 2.1111 0.002 0.004 305.0 0.000 2.1667 0.002 0.005 316.9 0.000 Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 23 2.2222 0.002 0.005 328.9 0.000 2.2778 0.002 0.005 340.9 0.000 2.3333 0.002 0.005 353.1 0.000 2.3889 0.002 0.005 365.4 0.000 2.4444 0.002 0.005 377.8 0.000 2.5000 0.002 0.005 390.2 0.000 2.5556 0.002 0.005 402.8 0.000 2.6111 0.002 0.006 415.5 0.000 2.6667 0.002 0.006 428.2 0.000 2.7222 0.002 0.006 441.1 0.000 2.7778 0.002 0.006 454.0 0.000 2.8333 0.002 0.006 467.0 0.000 2.8889 0.002 0.006 480.1 0.000 2.9444 0.002 0.006 493.3 0.000 3.0000 0.002 0.007 506.6 0.000 3.0556 0.002 0.007 519.9 0.000 3.1111 0.002 0.007 533.3 0.000 3.1667 0.002 0.007 546.8 0.000 3.2222 0.002 0.007 560.3 0.000 3.2778 0.002 0.007 573.9 0.000 3.3333 0.002 0.007 587.6 0.000 3.3889 0.002 0.007 601.3 0.000 3.4444 0.002 0.008 615.2 0.000 3.5000 0.002 0.008 629.0 0.000 3.5556 0.002 0.008 643.0 0.000 3.6111 0.002 0.008 656.9 0.000 3.6667 0.002 0.008 671.0 0.000 3.7222 0.002 0.008 685.1 0.000 3.7778 0.002 0.008 699.3 0.000 3.8333 0.002 0.009 713.5 0.000 3.8889 0.002 0.009 727.7 0.000 3.9444 0.002 0.009 742.1 0.000 4.0000 0.002 0.009 756.4 0.000 4.0556 0.002 0.009 770.9 0.000 4.1111 0.002 0.009 785.3 0.000 4.1667 0.002 0.009 799.9 0.000 4.2222 0.002 0.009 814.4 0.000 4.2778 0.002 0.010 829.0 0.000 4.3333 0.002 0.010 843.7 0.000 4.3889 0.002 0.010 858.4 0.000 4.4444 0.002 0.010 873.1 0.000 4.5000 0.002 0.010 887.9 0.000 4.5556 0.002 0.010 902.8 0.000 4.6111 0.002 0.010 917.6 0.000 4.6667 0.002 0.011 932.5 0.000 4.7222 0.002 0.011 947.5 0.000 4.7778 0.002 0.011 962.5 0.000 4.8333 0.002 0.011 977.5 0.000 4.8889 0.002 0.011 992.6 0.000 4.9444 0.002 0.011 1007.0.000 5.0000 0.002 0.011 1022.0.000 5.0556 0.002 0.011 1038.0.000 Woodbridge Bldg A 3/5/2020 2:34:29 PM Page 24 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:14.9 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:4.15 Total Impervious Area:10.75 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.438073 5 year 0.68801 10 year 0.829654 25 year 0.979713 50 year 1.07257 100 year 1.151549 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.344518 5 year 0.484638 10 year 0.590224 25 year 0.738999 50 year 0.861505 100 year 0.994471 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.430 0.314 1950 0.537 0.344 1951 0.965 0.730 1952 0.304 0.226 1953 0.246 0.265 1954 0.378 0.245 1955 0.602 0.279 1956 0.479 0.426 1957 0.387 0.307 1958 0.436 0.287 Woodbridge Bldg A 3/5/2020 2:35:02 PM Page 25 1959 0.374 0.259 1960 0.652 0.608 1961 0.368 0.420 1962 0.229 0.212 1963 0.314 0.265 1964 0.414 0.325 1965 0.296 0.400 1966 0.285 0.271 1967 0.596 0.324 1968 0.372 0.295 1969 0.364 0.273 1970 0.300 0.259 1971 0.321 0.314 1972 0.718 0.594 1973 0.326 0.387 1974 0.354 0.288 1975 0.480 0.315 1976 0.347 0.266 1977 0.041 0.264 1978 0.304 0.341 1979 0.184 0.259 1980 0.681 0.608 1981 0.272 0.287 1982 0.523 0.593 1983 0.469 0.275 1984 0.290 0.236 1985 0.172 0.264 1986 0.759 0.395 1987 0.672 0.566 1988 0.265 0.255 1989 0.173 0.241 1990 1.404 0.680 1991 0.846 0.580 1992 0.326 0.315 1993 0.340 0.215 1994 0.114 0.205 1995 0.487 0.380 1996 1.026 0.707 1997 0.858 0.707 1998 0.194 0.276 1999 0.805 0.577 2000 0.339 0.311 2001 0.061 0.279 2002 0.371 0.403 2003 0.474 0.285 2004 0.613 0.721 2005 0.440 0.283 2006 0.519 0.416 2007 1.042 0.885 2008 1.345 0.716 2009 0.660 0.440 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 1.4043 0.8848 2 1.3446 0.7299 3 1.0424 0.7208 Woodbridge Bldg A 3/5/2020 2:35:02 PM Page 26 4 1.0265 0.7160 5 0.9647 0.7067 6 0.8581 0.7065 7 0.8455 0.6800 8 0.8047 0.6078 9 0.7593 0.6077 10 0.7184 0.5945 11 0.6808 0.5929 12 0.6716 0.5799 13 0.6602 0.5769 14 0.6523 0.5664 15 0.6131 0.4399 16 0.6020 0.4256 17 0.5957 0.4200 18 0.5366 0.4159 19 0.5233 0.4028 20 0.5187 0.4001 21 0.4870 0.3947 22 0.4799 0.3869 23 0.4791 0.3798 24 0.4735 0.3444 25 0.4692 0.3414 26 0.4398 0.3245 27 0.4355 0.3237 28 0.4303 0.3150 29 0.4138 0.3146 30 0.3866 0.3138 31 0.3775 0.3138 32 0.3736 0.3110 33 0.3716 0.3073 34 0.3712 0.2947 35 0.3680 0.2879 36 0.3635 0.2872 37 0.3542 0.2871 38 0.3469 0.2846 39 0.3397 0.2832 40 0.3387 0.2791 41 0.3263 0.2789 42 0.3261 0.2764 43 0.3206 0.2752 44 0.3143 0.2734 45 0.3044 0.2707 46 0.3040 0.2657 47 0.2998 0.2649 48 0.2963 0.2646 49 0.2896 0.2641 50 0.2848 0.2639 51 0.2721 0.2594 52 0.2650 0.2590 53 0.2459 0.2586 54 0.2290 0.2551 55 0.1941 0.2453 56 0.1839 0.2409 57 0.1729 0.2357 58 0.1719 0.2255 59 0.1141 0.2149 60 0.0608 0.2120 61 0.0413 0.2047 Woodbridge Bldg A 3/5/2020 2:35:02 PM Page 28 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.2190 17556 17043 97 Pass 0.2277 16258 14899 91 Pass 0.2363 14998 13471 89 Pass 0.2449 13943 12523 89 Pass 0.2535 12865 11734 91 Pass 0.2621 11819 11058 93 Pass 0.2708 10966 10521 95 Pass 0.2794 10147 9809 96 Pass 0.2880 9383 9186 97 Pass 0.2966 8778 8562 97 Pass 0.3053 8164 7946 97 Pass 0.3139 7649 7366 96 Pass 0.3225 7086 6791 95 Pass 0.3311 6592 6192 93 Pass 0.3397 6177 5578 90 Pass 0.3484 5788 4922 85 Pass 0.3570 5471 4410 80 Pass 0.3656 5129 3897 75 Pass 0.3742 4815 3527 73 Pass 0.3828 4549 3364 73 Pass 0.3915 4265 3219 75 Pass 0.4001 4017 3106 77 Pass 0.4087 3805 3022 79 Pass 0.4173 3555 2911 81 Pass 0.4260 3360 2802 83 Pass 0.4346 3146 2699 85 Pass 0.4432 2954 2590 87 Pass 0.4518 2796 2488 88 Pass 0.4604 2603 2383 91 Pass 0.4691 2447 2291 93 Pass 0.4777 2319 2182 94 Pass 0.4863 2162 2038 94 Pass 0.4949 2043 1924 94 Pass 0.5035 1910 1807 94 Pass 0.5122 1790 1695 94 Pass 0.5208 1700 1591 93 Pass 0.5294 1594 1444 90 Pass 0.5380 1483 1316 88 Pass 0.5467 1387 1215 87 Pass 0.5553 1293 1101 85 Pass 0.5639 1226 1007 82 Pass 0.5725 1159 911 78 Pass 0.5811 1098 832 75 Pass 0.5898 1051 756 71 Pass 0.5984 998 664 66 Pass 0.6070 930 573 61 Pass 0.6156 885 530 59 Pass 0.6242 838 484 57 Pass 0.6329 790 429 54 Pass 0.6415 744 384 51 Pass 0.6501 713 347 48 Pass 0.6587 673 317 47 Pass 0.6674 633 278 43 Pass Woodbridge Bldg A 3/5/2020 2:35:02 PM Page 29 0.6760 600 238 39 Pass 0.6846 569 199 34 Pass 0.6932 539 168 31 Pass 0.7018 500 151 30 Pass 0.7105 474 131 27 Pass 0.7191 434 122 28 Pass 0.7277 403 117 29 Pass 0.7363 369 112 30 Pass 0.7450 350 110 31 Pass 0.7536 324 107 33 Pass 0.7622 296 97 32 Pass 0.7708 275 85 30 Pass 0.7794 256 71 27 Pass 0.7881 235 63 26 Pass 0.7967 218 56 25 Pass 0.8053 198 49 24 Pass 0.8139 182 45 24 Pass 0.8225 158 41 25 Pass 0.8312 145 37 25 Pass 0.8398 131 30 22 Pass 0.8484 119 21 17 Pass 0.8570 109 14 12 Pass 0.8657 97 4 4 Pass 0.8743 91 2 2 Pass 0.8829 82 1 1 Pass 0.8915 76 0 0 Pass 0.9001 69 0 0 Pass 0.9088 62 0 0 Pass 0.9174 55 0 0 Pass 0.9260 48 0 0 Pass 0.9346 41 0 0 Pass 0.9432 38 0 0 Pass 0.9519 33 0 0 Pass 0.9605 27 0 0 Pass 0.9691 22 0 0 Pass 0.9777 21 0 0 Pass 0.9864 20 0 0 Pass 0.9950 19 0 0 Pass 1.0036 17 0 0 Pass 1.0122 14 0 0 Pass 1.0208 12 0 0 Pass 1.0295 9 0 0 Pass 1.0381 4 0 0 Pass 1.0467 3 0 0 Pass 1.0553 3 0 0 Pass 1.0639 3 0 0 Pass 1.0726 3 0 0 Pass Woodbridge Bldg A 3/5/2020 2:35:02 PM Page 30 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:1.4436 acre-feet On-line facility target flow:1.7144 cfs. Adjusted for 15 min:1.7144 cfs. Off-line facility target flow:0.9646 cfs. Adjusted for 15 min:0.9646 cfs. Woodbridge Bldg A 3/5/2020 2:35:02 PM Page 31 LID Report Woodbridge Bldg A 3/5/2020 2:36:46 PM Page 32 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area:0.05 Total Impervious Area:2.36 Mitigated Landuse Totals for POC #2 Total Pervious Area:0.05 Total Impervious Area:2.36 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 0.903013 5 year 1.141654 10 year 1.303908 25 year 1.514492 50 year 1.675745 100 year 1.840977 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 0.903013 5 year 1.141654 10 year 1.303908 25 year 1.514492 50 year 1.675745 100 year 1.840977 Woodbridge Bldg A 3/5/2020 2:37:20 PM Page 38 Water Quality Water Quality BMP Flow and Volume for POC #2 On-line facility volume:0.2908 acre-feet On-line facility target flow:0.383 cfs. Adjusted for 15 min:0.383 cfs. Off-line facility target flow:0.2163 cfs. Adjusted for 15 min:0.2163 cfs. Woodbridge Bldg A 3/5/2020 2:37:20 PM Page 40 POC 3 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #3 Total Pervious Area:0.48 Total Impervious Area:0 Mitigated Landuse Totals for POC #3 Total Pervious Area:0 Total Impervious Area:0.48 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #3 Return Period Flow(cfs) 2 year 0.014112 5 year 0.022164 10 year 0.026727 25 year 0.031561 50 year 0.034553 100 year 0.037097 Flow Frequency Return Periods for Mitigated. POC #3 Return Period Flow(cfs) 2 year 0.183007 5 year 0.231159 10 year 0.263875 25 year 0.306313 50 year 0.338793 100 year 0.372062 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #3 Year Predeveloped Mitigated 1949 0.014 0.237 1950 0.017 0.256 1951 0.031 0.148 1952 0.010 0.132 1953 0.008 0.142 1954 0.012 0.149 1955 0.019 0.169 1956 0.015 0.166 1957 0.012 0.188 1958 0.014 0.152 1959 0.012 0.155 Woodbridge Bldg A 3/5/2020 2:37:52 PM Page 41 1960 0.021 0.152 1961 0.012 0.161 1962 0.007 0.140 1963 0.010 0.156 1964 0.013 0.153 1965 0.010 0.194 1966 0.009 0.130 1967 0.019 0.224 1968 0.012 0.254 1969 0.012 0.177 1970 0.010 0.170 1971 0.010 0.203 1972 0.023 0.210 1973 0.011 0.127 1974 0.011 0.185 1975 0.015 0.214 1976 0.011 0.144 1977 0.001 0.156 1978 0.010 0.190 1979 0.006 0.261 1980 0.022 0.234 1981 0.009 0.191 1982 0.017 0.270 1983 0.015 0.219 1984 0.009 0.138 1985 0.006 0.191 1986 0.024 0.165 1987 0.022 0.255 1988 0.009 0.155 1989 0.006 0.194 1990 0.045 0.326 1991 0.027 0.261 1992 0.011 0.137 1993 0.011 0.119 1994 0.004 0.129 1995 0.016 0.170 1996 0.033 0.180 1997 0.028 0.175 1998 0.006 0.178 1999 0.026 0.363 2000 0.011 0.181 2001 0.002 0.199 2002 0.012 0.232 2003 0.015 0.180 2004 0.020 0.340 2005 0.014 0.155 2006 0.017 0.137 2007 0.034 0.318 2008 0.043 0.256 2009 0.021 0.237 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #3 Rank Predeveloped Mitigated 1 0.0452 0.3634 2 0.0433 0.3400 3 0.0336 0.3261 4 0.0331 0.3178 Woodbridge Bldg A 3/5/2020 2:37:52 PM Page 42 5 0.0311 0.2697 6 0.0276 0.2606 7 0.0272 0.2605 8 0.0259 0.2561 9 0.0245 0.2560 10 0.0231 0.2552 11 0.0219 0.2542 12 0.0216 0.2370 13 0.0213 0.2365 14 0.0210 0.2338 15 0.0198 0.2319 16 0.0194 0.2236 17 0.0192 0.2195 18 0.0173 0.2137 19 0.0169 0.2099 20 0.0167 0.2033 21 0.0157 0.1988 22 0.0155 0.1940 23 0.0154 0.1936 24 0.0153 0.1912 25 0.0151 0.1908 26 0.0142 0.1904 27 0.0140 0.1884 28 0.0139 0.1855 29 0.0133 0.1809 30 0.0125 0.1805 31 0.0122 0.1801 32 0.0120 0.1776 33 0.0120 0.1767 34 0.0120 0.1752 35 0.0119 0.1705 36 0.0117 0.1696 37 0.0114 0.1687 38 0.0112 0.1660 39 0.0109 0.1654 40 0.0109 0.1609 41 0.0105 0.1558 42 0.0105 0.1556 43 0.0103 0.1554 44 0.0101 0.1550 45 0.0098 0.1548 46 0.0098 0.1527 47 0.0097 0.1521 48 0.0095 0.1520 49 0.0093 0.1488 50 0.0092 0.1481 51 0.0088 0.1437 52 0.0085 0.1422 53 0.0079 0.1402 54 0.0074 0.1385 55 0.0063 0.1373 56 0.0059 0.1371 57 0.0056 0.1317 58 0.0055 0.1297 59 0.0037 0.1292 60 0.0020 0.1271 61 0.0013 0.1188 Woodbridge Bldg A 3/5/2020 2:37:52 PM Page 48 POC 4 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #4 Total Pervious Area:1 Total Impervious Area:0 Mitigated Landuse Totals for POC #4 Total Pervious Area:4.08 Total Impervious Area:10.4 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #4 Return Period Flow(cfs) 2 year 0.029401 5 year 0.046175 10 year 0.055681 25 year 0.065753 50 year 0.071985 100 year 0.077285 Flow Frequency Return Periods for Mitigated. POC #4 Return Period Flow(cfs) 2 year 0.278554 5 year 0.425848 10 year 0.541655 25 year 0.71026 50 year 0.853015 100 year 1.011308 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #4 Year Predeveloped Mitigated 1949 0.029 0.188 1950 0.036 0.303 1951 0.065 0.681 1952 0.020 0.170 1953 0.017 0.211 1954 0.025 0.204 1955 0.040 0.200 1956 0.032 0.410 1957 0.026 0.204 1958 0.029 0.268 1959 0.025 0.188 Woodbridge Bldg A 3/5/2020 2:38:26 PM Page 49 1960 0.044 0.569 1961 0.025 0.331 1962 0.015 0.169 1963 0.021 0.210 1964 0.028 0.301 1965 0.020 0.363 1966 0.019 0.202 1967 0.040 0.285 1968 0.025 0.204 1969 0.024 0.199 1970 0.020 0.222 1971 0.022 0.235 1972 0.048 0.548 1973 0.022 0.356 1974 0.024 0.230 1975 0.032 0.195 1976 0.023 0.207 1977 0.003 0.178 1978 0.020 0.299 1979 0.012 0.160 1980 0.046 0.579 1981 0.018 0.208 1982 0.035 0.479 1983 0.031 0.214 1984 0.019 0.175 1985 0.012 0.184 1986 0.051 0.337 1987 0.045 0.531 1988 0.018 0.189 1989 0.012 0.181 1990 0.094 0.588 1991 0.057 0.527 1992 0.022 0.299 1993 0.023 0.174 1994 0.008 0.156 1995 0.033 0.334 1996 0.069 0.661 1997 0.058 0.658 1998 0.013 0.177 1999 0.054 0.551 2000 0.023 0.295 2001 0.004 0.150 2002 0.025 0.357 2003 0.032 0.199 2004 0.041 0.677 2005 0.030 0.206 2006 0.035 0.382 2007 0.070 0.835 2008 0.090 0.643 2009 0.044 0.378 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #4 Rank Predeveloped Mitigated 1 0.0942 0.8351 2 0.0902 0.6814 3 0.0700 0.6772 4 0.0689 0.6611 Woodbridge Bldg A 3/5/2020 2:38:26 PM Page 50 5 0.0647 0.6582 6 0.0576 0.6431 7 0.0567 0.5878 8 0.0540 0.5787 9 0.0510 0.5690 10 0.0482 0.5514 11 0.0457 0.5480 12 0.0451 0.5310 13 0.0443 0.5271 14 0.0438 0.4789 15 0.0411 0.4095 16 0.0404 0.3818 17 0.0400 0.3778 18 0.0360 0.3625 19 0.0351 0.3571 20 0.0348 0.3560 21 0.0327 0.3371 22 0.0322 0.3340 23 0.0322 0.3314 24 0.0318 0.3029 25 0.0315 0.3013 26 0.0295 0.2993 27 0.0292 0.2987 28 0.0289 0.2950 29 0.0278 0.2848 30 0.0259 0.2683 31 0.0253 0.2345 32 0.0251 0.2302 33 0.0249 0.2218 34 0.0249 0.2142 35 0.0247 0.2111 36 0.0244 0.2096 37 0.0238 0.2076 38 0.0233 0.2072 39 0.0228 0.2064 40 0.0227 0.2043 41 0.0219 0.2041 42 0.0219 0.2041 43 0.0215 0.2019 44 0.0211 0.2005 45 0.0204 0.1989 46 0.0204 0.1986 47 0.0201 0.1948 48 0.0199 0.1895 49 0.0194 0.1882 50 0.0191 0.1878 51 0.0183 0.1844 52 0.0178 0.1812 53 0.0165 0.1780 54 0.0154 0.1767 55 0.0130 0.1747 56 0.0123 0.1737 57 0.0116 0.1698 58 0.0115 0.1687 59 0.0077 0.1602 60 0.0041 0.1562 61 0.0028 0.1502 Woodbridge Bldg A 3/5/2020 2:38:26 PM Page 57 Appendix Predeveloped Schematic Woodbridge Bldg A 3/5/2020 2:38:27 PM Page 58 Mitigated Schematic Woodbridge Bldg A 3/5/2020 2:38:28 PM Page 75 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2020; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 2 General Model Information Project Name:Woodbridge Bldg A & B Site Name:Woodbridge Building A - Detention & WQ Site Address: City:Federal Way Report Date:3/25/2020 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:0.000 (adjusted) Version Date:2019/09/13 Version:4.2.17 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year Low Flow Threshold for POC3:50 Percent of the 2 Year High Flow Threshold for POC3:50 Year Low Flow Threshold for POC4:50 Percent of the 2 Year High Flow Threshold for POC4:50 Year Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 3 Landuse Basin Data Predeveloped Land Use PreDev - Building A - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 12.07 Pervious Total 12.07 Impervious Land Use acre Impervious Total 0 Basin Total 12.07 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 4 PreDev - Building A - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.14 Pervious Total 0.14 Impervious Land Use acre Impervious Total 0 Basin Total 0.14 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 5 PreDev - Building A ROW - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.02 Pervious Total 0.02 Impervious Land Use acre Impervious Total 0 Basin Total 0.02 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 6 PreDev - Building A ROW - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.28 Pervious Total 0.28 Impervious Land Use acre Impervious Total 0 Basin Total 0.28 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 7 PreDev - Building B Parcel Improvments - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 12.67 Pervious Total 12.67 Impervious Land Use acre Impervious Total 0 Basin Total 12.67 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 8 PreDev - Building A - Oil/Water Sep Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.05 Pervious Total 0.05 Impervious Land Use acre ROADS FLAT 2.36 Impervious Total 2.36 Basin Total 2.41 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 9 PreDev - Building A ROW - Un-Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.48 Pervious Total 0.48 Impervious Land Use acre Impervious Total 0 Basin Total 0.48 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 10 PreDev - Building B - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.03 Pervious Total 0.03 Impervious Land Use acre Impervious Total 0 Basin Total 0.03 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 11 POC 4 - Node Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 1 Pervious Total 1 Impervious Land Use acre Impervious Total 0 Basin Total 1 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 12 Mitigated Land Use Dev - Building B Parcel Improvments - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 3.39 Pervious Total 3.39 Impervious Land Use acre ROADS FLAT 4.37 ROOF TOPS FLAT 4.91 Impervious Total 9.28 Basin Total 12.67 Element Flows To: Surface Interflow Groundwater Detention Pond - 2:1 Side SlopesDetention Pond - 2:1 Side Slopes Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 13 Dev - Building A - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.2 C, Forest, Flat 0.92 Pervious Total 2.12 Impervious Land Use acre ROADS FLAT 4.76 ROOF TOPS FLAT 5.19 Impervious Total 9.95 Basin Total 12.07 Element Flows To: Surface Interflow Groundwater Detention Pond - 2:1 Side SlopesDetention Pond - 2:1 Side Slopes Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 14 Dev - Building A ROW - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.01 Pervious Total 0.01 Impervious Land Use acre ROADS FLAT 0.04 Impervious Total 0.04 Basin Total 0.05 Element Flows To: Surface Interflow Groundwater Detention Pond - 2:1 Side SlopesDetention Pond - 2:1 Side Slopes Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 15 Dev - Building A ROW - Bypass Bypass:Yes GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.28 Impervious Total 0.28 Basin Total 0.28 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 16 Dev - Building A - Bypass Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.07 Pervious Total 0.07 Impervious Land Use acre ROADS FLAT 0.07 Impervious Total 0.07 Basin Total 0.14 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 17 Dev - Building A - Oil/Water Sep Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.05 Pervious Total 0.05 Impervious Land Use acre ROADS FLAT 2.36 Impervious Total 2.36 Basin Total 2.41 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 18 PreDev - Building A ROW - Un-Detained Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre SIDEWALKS FLAT 0.48 Impervious Total 0.48 Basin Total 0.48 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 19 Dev - Building B - Bypass Bypass:Yes GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.03 Impervious Total 0.03 Basin Total 0.03 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 21 Mitigated Routing Detention Pond - 2:1 Side Slopes Bottom Length:190.00 ft. Bottom Width:265.00 ft. Depth:9 ft. Volume at riser head:10.0451 acre-feet. Side slope 1:2 To 1 Side slope 2:2 To 1 Side slope 3:2 To 1 Side slope 4:2 To 1 Discharge Structure Riser Height:7.5 ft. Riser Diameter:24 in. Notch Type:Rectangular Notch Width:0.021 ft. Notch Height:1.750 ft. Orifice 1 Diameter:2.375 in.Elevation:0 ft. Orifice 2 Diameter:2.75 in.Elevation:4.25 ft. Orifice 3 Diameter:2.75 in.Elevation:5.25 ft. Element Flows To: Outlet 1 Outlet 2 POC 1 Analysis Node Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 374.50 1.155 0.000 0.000 0.000 374.60 1.160 0.115 0.048 0.000 374.70 1.164 0.232 0.068 0.000 374.80 1.168 0.348 0.083 0.000 374.90 1.172 0.465 0.096 0.000 375.00 1.176 0.583 0.108 0.000 375.10 1.181 0.701 0.118 0.000 375.20 1.185 0.819 0.128 0.000 375.30 1.189 0.938 0.136 0.000 375.40 1.193 1.057 0.145 0.000 375.50 1.198 1.176 0.153 0.000 375.60 1.202 1.296 0.160 0.000 375.70 1.206 1.417 0.167 0.000 375.80 1.210 1.538 0.174 0.000 375.90 1.215 1.659 0.181 0.000 376.00 1.219 1.781 0.187 0.000 376.10 1.223 1.903 0.193 0.000 376.20 1.228 2.026 0.199 0.000 376.30 1.232 2.149 0.205 0.000 376.40 1.236 2.272 0.211 0.000 376.50 1.240 2.396 0.216 0.000 376.60 1.245 2.520 0.221 0.000 376.70 1.249 2.645 0.227 0.000 376.80 1.253 2.770 0.232 0.000 376.90 1.258 2.896 0.237 0.000 377.00 1.262 3.022 0.242 0.000 377.10 1.267 3.148 0.246 0.000 377.20 1.271 3.275 0.251 0.000 377.30 1.275 3.402 0.256 0.000 377.40 1.280 3.530 0.260 0.000 Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 22 377.50 1.284 3.659 0.265 0.000 377.60 1.288 3.787 0.269 0.000 377.70 1.293 3.916 0.273 0.000 377.80 1.297 4.046 0.278 0.000 377.90 1.302 4.176 0.282 0.000 378.00 1.306 4.306 0.286 0.000 378.10 1.311 4.437 0.290 0.000 378.20 1.315 4.568 0.294 0.000 378.30 1.320 4.700 0.298 0.000 378.40 1.324 4.832 0.302 0.000 378.50 1.328 4.965 0.306 0.000 378.60 1.333 5.098 0.309 0.000 378.70 1.337 5.232 0.313 0.000 378.80 1.342 5.366 0.363 0.000 378.90 1.346 5.500 0.400 0.000 379.00 1.351 5.635 0.427 0.000 379.10 1.355 5.771 0.449 0.000 379.20 1.360 5.906 0.469 0.000 379.30 1.364 6.043 0.487 0.000 379.40 1.369 6.179 0.504 0.000 379.50 1.374 6.317 0.520 0.000 379.60 1.378 6.454 0.534 0.000 379.70 1.383 6.592 0.549 0.000 379.80 1.387 6.731 0.608 0.000 379.90 1.392 6.870 0.655 0.000 380.00 1.396 7.009 0.691 0.000 380.10 1.401 7.149 0.722 0.000 380.20 1.406 7.289 0.750 0.000 380.30 1.410 7.430 0.777 0.000 380.40 1.415 7.572 0.804 0.000 380.50 1.419 7.713 0.832 0.000 380.60 1.424 7.856 0.859 0.000 380.70 1.429 7.998 0.886 0.000 380.80 1.433 8.141 0.913 0.000 380.90 1.438 8.285 0.939 0.000 381.00 1.443 8.429 0.965 0.000 381.10 1.447 8.574 0.991 0.000 381.20 1.452 8.719 1.016 0.000 381.30 1.457 8.864 1.042 0.000 381.40 1.461 9.010 1.068 0.000 381.50 1.466 9.156 1.094 0.000 381.60 1.471 9.303 1.120 0.000 381.70 1.475 9.451 1.177 0.000 381.80 1.480 9.598 1.207 0.000 381.90 1.485 9.747 1.236 0.000 382.00 1.489 9.895 1.266 0.000 382.10 1.494 10.04 1.952 0.000 382.20 1.499 10.19 3.183 0.000 382.30 1.504 10.34 4.732 0.000 382.40 1.508 10.49 6.460 0.000 382.50 1.513 10.64 8.227 0.000 382.60 1.518 10.79 9.894 0.000 382.70 1.523 10.95 11.33 0.000 382.80 1.528 11.10 12.47 0.000 382.90 1.532 11.25 13.28 0.000 383.00 1.537 11.41 13.87 0.000 383.10 1.542 11.56 14.63 0.000 383.20 1.547 11.71 15.23 0.000 Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 23 383.30 1.552 11.87 15.81 0.000 383.40 1.556 12.02 16.36 0.000 383.50 1.561 12.18 16.90 0.000 383.60 1.566 12.34 17.42 0.000 Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 24 POC 1 Analysis Node Bottom Length:10.00 ft. Bottom Width:10.00 ft. Manning's n:0.03 Channel bottom slope 1:0.05 To 1 Channel Left side slope 0:0 To 1 Channel right side slope 2:0 To 1 Discharge Structure Riser Height:0 ft. Riser Diameter:0 in. Element Flows To: Outlet 1 Outlet 2 Channel Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.002 0.000 0.000 0.000 0.0556 0.002 0.000 0.891 0.000 0.1111 0.002 0.000 2.810 0.000 0.1667 0.002 0.000 5.484 0.000 0.2222 0.002 0.000 8.795 0.000 0.2778 0.002 0.000 12.66 0.000 0.3333 0.002 0.000 17.04 0.000 0.3889 0.002 0.000 21.89 0.000 0.4444 0.002 0.001 27.16 0.000 0.5000 0.002 0.001 32.82 0.000 0.5556 0.002 0.001 38.86 0.000 0.6111 0.002 0.001 45.25 0.000 0.6667 0.002 0.001 51.97 0.000 0.7222 0.002 0.001 59.01 0.000 0.7778 0.002 0.001 66.34 0.000 0.8333 0.002 0.001 73.95 0.000 0.8889 0.002 0.002 81.83 0.000 0.9444 0.002 0.002 89.96 0.000 1.0000 0.002 0.002 98.34 0.000 1.0556 0.002 0.002 106.9 0.000 1.1111 0.002 0.002 115.8 0.000 1.1667 0.002 0.002 124.8 0.000 1.2222 0.002 0.002 134.1 0.000 1.2778 0.002 0.003 143.5 0.000 1.3333 0.002 0.003 153.2 0.000 1.3889 0.002 0.003 163.0 0.000 1.4444 0.002 0.003 173.0 0.000 1.5000 0.002 0.003 183.2 0.000 1.5556 0.002 0.003 193.6 0.000 1.6111 0.002 0.003 204.1 0.000 1.6667 0.002 0.003 214.7 0.000 1.7222 0.002 0.004 225.6 0.000 1.7778 0.002 0.004 236.5 0.000 1.8333 0.002 0.004 247.6 0.000 1.8889 0.002 0.004 258.8 0.000 1.9444 0.002 0.004 270.2 0.000 2.0000 0.002 0.004 281.7 0.000 2.0556 0.002 0.004 293.3 0.000 2.1111 0.002 0.004 305.0 0.000 2.1667 0.002 0.005 316.9 0.000 Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 25 2.2222 0.002 0.005 328.9 0.000 2.2778 0.002 0.005 340.9 0.000 2.3333 0.002 0.005 353.1 0.000 2.3889 0.002 0.005 365.4 0.000 2.4444 0.002 0.005 377.8 0.000 2.5000 0.002 0.005 390.2 0.000 2.5556 0.002 0.005 402.8 0.000 2.6111 0.002 0.006 415.5 0.000 2.6667 0.002 0.006 428.2 0.000 2.7222 0.002 0.006 441.1 0.000 2.7778 0.002 0.006 454.0 0.000 2.8333 0.002 0.006 467.0 0.000 2.8889 0.002 0.006 480.1 0.000 2.9444 0.002 0.006 493.3 0.000 3.0000 0.002 0.007 506.6 0.000 3.0556 0.002 0.007 519.9 0.000 3.1111 0.002 0.007 533.3 0.000 3.1667 0.002 0.007 546.8 0.000 3.2222 0.002 0.007 560.3 0.000 3.2778 0.002 0.007 573.9 0.000 3.3333 0.002 0.007 587.6 0.000 3.3889 0.002 0.007 601.3 0.000 3.4444 0.002 0.008 615.2 0.000 3.5000 0.002 0.008 629.0 0.000 3.5556 0.002 0.008 643.0 0.000 3.6111 0.002 0.008 656.9 0.000 3.6667 0.002 0.008 671.0 0.000 3.7222 0.002 0.008 685.1 0.000 3.7778 0.002 0.008 699.3 0.000 3.8333 0.002 0.009 713.5 0.000 3.8889 0.002 0.009 727.7 0.000 3.9444 0.002 0.009 742.1 0.000 4.0000 0.002 0.009 756.4 0.000 4.0556 0.002 0.009 770.9 0.000 4.1111 0.002 0.009 785.3 0.000 4.1667 0.002 0.009 799.9 0.000 4.2222 0.002 0.009 814.4 0.000 4.2778 0.002 0.010 829.0 0.000 4.3333 0.002 0.010 843.7 0.000 4.3889 0.002 0.010 858.4 0.000 4.4444 0.002 0.010 873.1 0.000 4.5000 0.002 0.010 887.9 0.000 4.5556 0.002 0.010 902.8 0.000 4.6111 0.002 0.010 917.6 0.000 4.6667 0.002 0.011 932.5 0.000 4.7222 0.002 0.011 947.5 0.000 4.7778 0.002 0.011 962.5 0.000 4.8333 0.002 0.011 977.5 0.000 4.8889 0.002 0.011 992.6 0.000 4.9444 0.002 0.011 1007.0.000 5.0000 0.002 0.011 1022.0.000 5.0556 0.002 0.011 1038.0.000 Woodbridge Bldg A & B 3/25/2020 1:12:11 PM Page 26 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:25.21 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:5.59 Total Impervious Area:19.65 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.741195 5 year 1.164076 10 year 1.40373 25 year 1.657622 50 year 1.814732 100 year 1.94836 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.495628 5 year 0.71695 10 year 0.88379 25 year 1.1187 50 year 1.311875 100 year 1.521213 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.728 0.398 1950 0.908 0.530 1951 1.632 1.109 1952 0.514 0.311 1953 0.416 0.503 1954 0.639 0.351 1955 1.019 0.390 1956 0.811 0.754 1957 0.654 0.394 1958 0.737 0.424 Woodbridge Bldg A & B 3/25/2020 1:12:40 PM Page 27 1959 0.632 0.371 1960 1.104 0.858 1961 0.623 0.624 1962 0.387 0.297 1963 0.532 0.430 1964 0.700 0.538 1965 0.501 0.634 1966 0.482 0.384 1967 1.008 0.508 1968 0.629 0.375 1969 0.615 0.365 1970 0.507 0.467 1971 0.542 0.416 1972 1.215 0.925 1973 0.552 0.618 1974 0.599 0.387 1975 0.812 0.409 1976 0.587 0.354 1977 0.070 0.351 1978 0.515 0.521 1979 0.311 0.316 1980 1.152 0.947 1981 0.460 0.374 1982 0.885 0.823 1983 0.794 0.356 1984 0.490 0.324 1985 0.291 0.331 1986 1.285 0.519 1987 1.136 0.808 1988 0.448 0.362 1989 0.293 0.328 1990 2.376 0.904 1991 1.431 0.930 1992 0.552 0.476 1993 0.575 0.293 1994 0.193 0.283 1995 0.824 0.591 1996 1.737 1.051 1997 1.452 1.067 1998 0.328 0.359 1999 1.361 0.925 2000 0.573 0.460 2001 0.103 0.350 2002 0.628 0.522 2003 0.801 0.364 2004 1.037 1.034 2005 0.744 0.363 2006 0.878 0.758 2007 1.764 1.273 2008 2.275 0.958 2009 1.117 0.615 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 2.3759 1.2725 2 2.2750 1.1094 3 1.7636 1.0667 Woodbridge Bldg A & B 3/25/2020 1:12:40 PM Page 28 4 1.7367 1.0513 5 1.6322 1.0337 6 1.4518 0.9578 7 1.4306 0.9470 8 1.3614 0.9297 9 1.2847 0.9252 10 1.2155 0.9246 11 1.1519 0.9041 12 1.1364 0.8582 13 1.1170 0.8235 14 1.1036 0.8081 15 1.0373 0.7577 16 1.0186 0.7544 17 1.0078 0.6339 18 0.9078 0.6239 19 0.8854 0.6180 20 0.8776 0.6153 21 0.8241 0.5913 22 0.8120 0.5382 23 0.8106 0.5295 24 0.8012 0.5218 25 0.7938 0.5211 26 0.7442 0.5187 27 0.7369 0.5076 28 0.7281 0.5026 29 0.7001 0.4763 30 0.6541 0.4674 31 0.6388 0.4596 32 0.6321 0.4297 33 0.6287 0.4238 34 0.6280 0.4160 35 0.6226 0.4090 36 0.6150 0.3977 37 0.5993 0.3942 38 0.5870 0.3903 39 0.5747 0.3868 40 0.5731 0.3842 41 0.5521 0.3754 42 0.5517 0.3740 43 0.5424 0.3713 44 0.5319 0.3646 45 0.5151 0.3643 46 0.5143 0.3632 47 0.5072 0.3618 48 0.5013 0.3594 49 0.4900 0.3558 50 0.4819 0.3538 51 0.4604 0.3508 52 0.4484 0.3506 53 0.4160 0.3503 54 0.3874 0.3308 55 0.3284 0.3284 56 0.3112 0.3237 57 0.2926 0.3162 58 0.2908 0.3105 59 0.1931 0.2971 60 0.1028 0.2933 61 0.0699 0.2832 Woodbridge Bldg A & B 3/25/2020 1:12:40 PM Page 30 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.3706 17618 17156 97 Pass 0.3852 16174 16003 98 Pass 0.3998 15017 15013 99 Pass 0.4144 13873 13676 98 Pass 0.4289 12872 12572 97 Pass 0.4435 11847 11428 96 Pass 0.4581 10902 10252 94 Pass 0.4727 10149 9253 91 Pass 0.4873 9396 8376 89 Pass 0.5019 8769 7514 85 Pass 0.5165 8164 6699 82 Pass 0.5311 7593 5867 77 Pass 0.5456 7082 5076 71 Pass 0.5602 6592 4558 69 Pass 0.5748 6166 4252 68 Pass 0.5894 5784 4038 69 Pass 0.6040 5454 3869 70 Pass 0.6186 5110 3720 72 Pass 0.6332 4808 3566 74 Pass 0.6478 4539 3422 75 Pass 0.6623 4259 3287 77 Pass 0.6769 4030 3140 77 Pass 0.6915 3794 2939 77 Pass 0.7061 3548 2759 77 Pass 0.7207 3345 2565 76 Pass 0.7353 3138 2359 75 Pass 0.7499 2960 2205 74 Pass 0.7645 2789 2065 74 Pass 0.7790 2597 1916 73 Pass 0.7936 2451 1789 72 Pass 0.8082 2308 1631 70 Pass 0.8228 2165 1496 69 Pass 0.8374 2028 1377 67 Pass 0.8520 1910 1250 65 Pass 0.8666 1790 1094 61 Pass 0.8812 1688 967 57 Pass 0.8957 1594 859 53 Pass 0.9103 1483 733 49 Pass 0.9249 1386 641 46 Pass 0.9395 1293 549 42 Pass 0.9541 1219 487 39 Pass 0.9687 1156 433 37 Pass 0.9833 1098 380 34 Pass 0.9978 1050 334 31 Pass 1.0124 997 261 26 Pass 1.0270 930 217 23 Pass 1.0416 884 191 21 Pass 1.0562 837 165 19 Pass 1.0708 790 146 18 Pass 1.0854 743 134 18 Pass 1.1000 718 123 17 Pass 1.1145 671 114 16 Pass 1.1291 630 109 17 Pass Woodbridge Bldg A & B 3/25/2020 1:12:40 PM Page 31 1.1437 596 107 17 Pass 1.1583 566 103 18 Pass 1.1729 540 94 17 Pass 1.1875 497 81 16 Pass 1.2021 473 60 12 Pass 1.2167 436 50 11 Pass 1.2312 400 38 9 Pass 1.2458 370 32 8 Pass 1.2604 348 11 3 Pass 1.2750 323 0 0 Pass 1.2896 296 0 0 Pass 1.3042 272 0 0 Pass 1.3188 257 0 0 Pass 1.3334 235 0 0 Pass 1.3479 218 0 0 Pass 1.3625 198 0 0 Pass 1.3771 180 0 0 Pass 1.3917 158 0 0 Pass 1.4063 145 0 0 Pass 1.4209 130 0 0 Pass 1.4355 119 0 0 Pass 1.4501 109 0 0 Pass 1.4646 97 0 0 Pass 1.4792 91 0 0 Pass 1.4938 82 0 0 Pass 1.5084 76 0 0 Pass 1.5230 69 0 0 Pass 1.5376 61 0 0 Pass 1.5522 54 0 0 Pass 1.5667 48 0 0 Pass 1.5813 41 0 0 Pass 1.5959 38 0 0 Pass 1.6105 33 0 0 Pass 1.6251 27 0 0 Pass 1.6397 22 0 0 Pass 1.6543 21 0 0 Pass 1.6689 20 0 0 Pass 1.6834 19 0 0 Pass 1.6980 17 0 0 Pass 1.7126 14 0 0 Pass 1.7272 12 0 0 Pass 1.7418 9 0 0 Pass 1.7564 4 0 0 Pass 1.7710 3 0 0 Pass 1.7856 3 0 0 Pass 1.8001 3 0 0 Pass 1.8147 3 0 0 Pass Woodbridge Bldg A & B 3/25/2020 1:12:40 PM Page 32 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:1.4436 acre-feet On-line facility target flow:1.7144 cfs. Adjusted for 15 min:1.7144 cfs. Off-line facility target flow:0.9646 cfs. Adjusted for 15 min:0.9646 cfs. Woodbridge Bldg A & B 3/25/2020 1:14:01 PM Page 34 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area:0.05 Total Impervious Area:2.36 Mitigated Landuse Totals for POC #2 Total Pervious Area:0.05 Total Impervious Area:2.36 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 0.903013 5 year 1.141654 10 year 1.303908 25 year 1.514492 50 year 1.675745 100 year 1.840977 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 0.903013 5 year 1.141654 10 year 1.303908 25 year 1.514492 50 year 1.675745 100 year 1.840977 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 1.173 1.173 1950 1.260 1.260 1951 0.732 0.732 1952 0.648 0.648 1953 0.700 0.700 1954 0.734 0.734 1955 0.832 0.832 1956 0.819 0.819 1957 0.931 0.931 1958 0.749 0.749 1959 0.762 0.762 Woodbridge Bldg A & B 3/25/2020 1:14:31 PM Page 35 1960 0.753 0.753 1961 0.795 0.795 1962 0.690 0.690 1963 0.769 0.769 1964 0.751 0.751 1965 0.959 0.959 1966 0.640 0.640 1967 1.103 1.103 1968 1.254 1.254 1969 0.874 0.874 1970 0.841 0.841 1971 1.004 1.004 1972 1.040 1.040 1973 0.625 0.625 1974 0.916 0.916 1975 1.051 1.051 1976 0.710 0.710 1977 0.765 0.765 1978 0.936 0.936 1979 1.282 1.282 1980 1.159 1.159 1981 0.943 0.943 1982 1.332 1.332 1983 1.081 1.081 1984 0.683 0.683 1985 0.941 0.941 1986 0.814 0.814 1987 1.256 1.256 1988 0.761 0.761 1989 0.952 0.952 1990 1.622 1.622 1991 1.293 1.293 1992 0.676 0.676 1993 0.585 0.585 1994 0.635 0.635 1995 0.836 0.836 1996 0.893 0.893 1997 0.866 0.866 1998 0.875 0.875 1999 1.797 1.797 2000 0.893 0.893 2001 0.978 0.978 2002 1.147 1.147 2003 0.892 0.892 2004 1.680 1.680 2005 0.768 0.768 2006 0.679 0.679 2007 1.571 1.571 2008 1.270 1.270 2009 1.163 1.163 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #2 Rank Predeveloped Mitigated 1 1.7967 1.7967 2 1.6803 1.6803 3 1.6222 1.6222 4 1.5713 1.5713 Woodbridge Bldg A & B 3/25/2020 1:14:31 PM Page 36 5 1.3321 1.3321 6 1.2927 1.2927 7 1.2822 1.2822 8 1.2700 1.2700 9 1.2605 1.2605 10 1.2562 1.2562 11 1.2541 1.2541 12 1.1726 1.1726 13 1.1631 1.1631 14 1.1595 1.1595 15 1.1475 1.1475 16 1.1029 1.1029 17 1.0810 1.0810 18 1.0507 1.0507 19 1.0401 1.0401 20 1.0035 1.0035 21 0.9782 0.9782 22 0.9594 0.9594 23 0.9518 0.9518 24 0.9432 0.9432 25 0.9412 0.9412 26 0.9364 0.9364 27 0.9308 0.9308 28 0.9165 0.9165 29 0.8933 0.8933 30 0.8930 0.8930 31 0.8915 0.8915 32 0.8750 0.8750 33 0.8736 0.8736 34 0.8665 0.8665 35 0.8413 0.8413 36 0.8360 0.8360 37 0.8319 0.8319 38 0.8188 0.8188 39 0.8144 0.8144 40 0.7946 0.7946 41 0.7692 0.7692 42 0.7681 0.7681 43 0.7652 0.7652 44 0.7622 0.7622 45 0.7611 0.7611 46 0.7528 0.7528 47 0.7514 0.7514 48 0.7491 0.7491 49 0.7344 0.7344 50 0.7323 0.7323 51 0.7099 0.7099 52 0.6999 0.6999 53 0.6904 0.6904 54 0.6831 0.6831 55 0.6791 0.6791 56 0.6765 0.6765 57 0.6481 0.6481 58 0.6396 0.6396 59 0.6352 0.6352 60 0.6250 0.6250 61 0.5850 0.5850 Woodbridge Bldg A & B 3/25/2020 1:14:31 PM Page 38 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.4515 1796 1796 100 Pass 0.4639 1646 1646 100 Pass 0.4762 1463 1463 100 Pass 0.4886 1342 1342 100 Pass 0.5010 1225 1225 100 Pass 0.5133 1101 1101 100 Pass 0.5257 1000 1000 100 Pass 0.5381 916 916 100 Pass 0.5504 854 854 100 Pass 0.5628 789 789 100 Pass 0.5752 722 722 100 Pass 0.5875 666 666 100 Pass 0.5999 609 609 100 Pass 0.6123 567 567 100 Pass 0.6246 531 531 100 Pass 0.6370 489 489 100 Pass 0.6494 447 447 100 Pass 0.6617 418 418 100 Pass 0.6741 386 386 100 Pass 0.6865 363 363 100 Pass 0.6988 338 338 100 Pass 0.7112 314 314 100 Pass 0.7236 293 293 100 Pass 0.7359 272 272 100 Pass 0.7483 255 255 100 Pass 0.7607 236 236 100 Pass 0.7730 220 220 100 Pass 0.7854 207 207 100 Pass 0.7978 195 195 100 Pass 0.8101 180 180 100 Pass 0.8225 171 171 100 Pass 0.8349 161 161 100 Pass 0.8472 146 146 100 Pass 0.8596 139 139 100 Pass 0.8720 135 135 100 Pass 0.8843 121 121 100 Pass 0.8967 113 113 100 Pass 0.9091 107 107 100 Pass 0.9214 104 104 100 Pass 0.9338 100 100 100 Pass 0.9461 91 91 100 Pass 0.9585 88 88 100 Pass 0.9709 82 82 100 Pass 0.9832 73 73 100 Pass 0.9956 71 71 100 Pass 1.0080 67 67 100 Pass 1.0203 64 64 100 Pass 1.0327 62 62 100 Pass 1.0451 59 59 100 Pass 1.0574 54 54 100 Pass 1.0698 53 53 100 Pass 1.0822 52 52 100 Pass 1.0945 50 50 100 Pass Woodbridge Bldg A & B 3/25/2020 1:14:31 PM Page 39 1.1069 47 47 100 Pass 1.1193 44 44 100 Pass 1.1316 40 40 100 Pass 1.1440 38 38 100 Pass 1.1564 34 34 100 Pass 1.1687 31 31 100 Pass 1.1811 29 29 100 Pass 1.1935 28 28 100 Pass 1.2058 25 25 100 Pass 1.2182 22 22 100 Pass 1.2306 21 21 100 Pass 1.2429 20 20 100 Pass 1.2553 16 16 100 Pass 1.2677 14 14 100 Pass 1.2800 12 12 100 Pass 1.2924 10 10 100 Pass 1.3048 9 9 100 Pass 1.3171 9 9 100 Pass 1.3295 9 9 100 Pass 1.3419 8 8 100 Pass 1.3542 8 8 100 Pass 1.3666 8 8 100 Pass 1.3790 8 8 100 Pass 1.3913 8 8 100 Pass 1.4037 8 8 100 Pass 1.4161 8 8 100 Pass 1.4284 8 8 100 Pass 1.4408 7 7 100 Pass 1.4532 7 7 100 Pass 1.4655 7 7 100 Pass 1.4779 7 7 100 Pass 1.4903 7 7 100 Pass 1.5026 6 6 100 Pass 1.5150 6 6 100 Pass 1.5274 6 6 100 Pass 1.5397 6 6 100 Pass 1.5521 6 6 100 Pass 1.5645 6 6 100 Pass 1.5768 5 5 100 Pass 1.5892 5 5 100 Pass 1.6015 4 4 100 Pass 1.6139 4 4 100 Pass 1.6263 3 3 100 Pass 1.6386 2 2 100 Pass 1.6510 2 2 100 Pass 1.6634 2 2 100 Pass 1.6757 2 2 100 Pass Woodbridge Bldg A & B 3/25/2020 1:14:31 PM Page 40 Water Quality Water Quality BMP Flow and Volume for POC #2 On-line facility volume:0.6917 acre-feet On-line facility target flow:0.9016 cfs. Adjusted for 15 min:0.9016 cfs. Off-line facility target flow:0.5095 cfs. Adjusted for 15 min:0.5095 cfs. Woodbridge Bldg A & B 3/25/2020 1:14:31 PM Page 42 POC 3 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #3 Total Pervious Area:0.48 Total Impervious Area:0 Mitigated Landuse Totals for POC #3 Total Pervious Area:0 Total Impervious Area:0.48 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #3 Return Period Flow(cfs) 2 year 0.014112 5 year 0.022164 10 year 0.026727 25 year 0.031561 50 year 0.034553 100 year 0.037097 Flow Frequency Return Periods for Mitigated. POC #3 Return Period Flow(cfs) 2 year 0.183007 5 year 0.231159 10 year 0.263875 25 year 0.306313 50 year 0.338793 100 year 0.372062 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #3 Year Predeveloped Mitigated 1949 0.014 0.237 1950 0.017 0.256 1951 0.031 0.148 1952 0.010 0.132 1953 0.008 0.142 1954 0.012 0.149 1955 0.019 0.169 1956 0.015 0.166 1957 0.012 0.188 1958 0.014 0.152 1959 0.012 0.155 Woodbridge Bldg A & B 3/25/2020 1:14:59 PM Page 43 1960 0.021 0.152 1961 0.012 0.161 1962 0.007 0.140 1963 0.010 0.156 1964 0.013 0.153 1965 0.010 0.194 1966 0.009 0.130 1967 0.019 0.224 1968 0.012 0.254 1969 0.012 0.177 1970 0.010 0.170 1971 0.010 0.203 1972 0.023 0.210 1973 0.011 0.127 1974 0.011 0.185 1975 0.015 0.214 1976 0.011 0.144 1977 0.001 0.156 1978 0.010 0.190 1979 0.006 0.261 1980 0.022 0.234 1981 0.009 0.191 1982 0.017 0.270 1983 0.015 0.219 1984 0.009 0.138 1985 0.006 0.191 1986 0.024 0.165 1987 0.022 0.255 1988 0.009 0.155 1989 0.006 0.194 1990 0.045 0.326 1991 0.027 0.261 1992 0.011 0.137 1993 0.011 0.119 1994 0.004 0.129 1995 0.016 0.170 1996 0.033 0.180 1997 0.028 0.175 1998 0.006 0.178 1999 0.026 0.363 2000 0.011 0.181 2001 0.002 0.199 2002 0.012 0.232 2003 0.015 0.180 2004 0.020 0.340 2005 0.014 0.155 2006 0.017 0.137 2007 0.034 0.318 2008 0.043 0.256 2009 0.021 0.237 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #3 Rank Predeveloped Mitigated 1 0.0452 0.3634 2 0.0433 0.3400 3 0.0336 0.3261 4 0.0331 0.3178 Woodbridge Bldg A & B 3/25/2020 1:14:59 PM Page 44 5 0.0311 0.2697 6 0.0276 0.2606 7 0.0272 0.2605 8 0.0259 0.2561 9 0.0245 0.2560 10 0.0231 0.2552 11 0.0219 0.2542 12 0.0216 0.2370 13 0.0213 0.2365 14 0.0210 0.2338 15 0.0198 0.2319 16 0.0194 0.2236 17 0.0192 0.2195 18 0.0173 0.2137 19 0.0169 0.2099 20 0.0167 0.2033 21 0.0157 0.1988 22 0.0155 0.1940 23 0.0154 0.1936 24 0.0153 0.1912 25 0.0151 0.1908 26 0.0142 0.1904 27 0.0140 0.1884 28 0.0139 0.1855 29 0.0133 0.1809 30 0.0125 0.1805 31 0.0122 0.1801 32 0.0120 0.1776 33 0.0120 0.1767 34 0.0120 0.1752 35 0.0119 0.1705 36 0.0117 0.1696 37 0.0114 0.1687 38 0.0112 0.1660 39 0.0109 0.1654 40 0.0109 0.1609 41 0.0105 0.1558 42 0.0105 0.1556 43 0.0103 0.1554 44 0.0101 0.1550 45 0.0098 0.1548 46 0.0098 0.1527 47 0.0097 0.1521 48 0.0095 0.1520 49 0.0093 0.1488 50 0.0092 0.1481 51 0.0088 0.1437 52 0.0085 0.1422 53 0.0079 0.1402 54 0.0074 0.1385 55 0.0063 0.1373 56 0.0059 0.1371 57 0.0056 0.1317 58 0.0055 0.1297 59 0.0037 0.1292 60 0.0020 0.1271 61 0.0013 0.1188 Woodbridge Bldg A & B 3/25/2020 1:15:00 PM Page 50 POC 4 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #4 Total Pervious Area:1 Total Impervious Area:0 Mitigated Landuse Totals for POC #4 Total Pervious Area:5.52 Total Impervious Area:19.27 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #4 Return Period Flow(cfs) 2 year 0.029401 5 year 0.046175 10 year 0.055681 25 year 0.065753 50 year 0.071985 100 year 0.077285 Flow Frequency Return Periods for Mitigated. POC #4 Return Period Flow(cfs) 2 year 0.439527 5 year 0.67368 10 year 0.854151 25 year 1.112226 50 year 1.32707 100 year 1.561953 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #4 Year Predeveloped Mitigated 1949 0.029 0.287 1950 0.036 0.486 1951 0.065 1.065 1952 0.020 0.261 1953 0.017 0.463 1954 0.025 0.302 1955 0.040 0.294 1956 0.032 0.727 1957 0.026 0.299 1958 0.029 0.407 1959 0.025 0.294 Woodbridge Bldg A & B 3/25/2020 1:15:29 PM Page 51 1960 0.044 0.828 1961 0.025 0.533 1962 0.015 0.262 1963 0.021 0.416 1964 0.028 0.513 1965 0.020 0.615 1966 0.019 0.346 1967 0.040 0.491 1968 0.025 0.310 1969 0.024 0.309 1970 0.020 0.452 1971 0.022 0.363 1972 0.048 0.888 1973 0.022 0.603 1974 0.024 0.343 1975 0.032 0.290 1976 0.023 0.307 1977 0.003 0.263 1978 0.020 0.477 1979 0.012 0.240 1980 0.046 0.923 1981 0.018 0.334 1982 0.035 0.728 1983 0.031 0.329 1984 0.019 0.264 1985 0.012 0.270 1986 0.051 0.468 1987 0.045 0.779 1988 0.018 0.293 1989 0.012 0.269 1990 0.094 0.856 1991 0.057 0.883 1992 0.022 0.455 1993 0.023 0.258 1994 0.008 0.233 1995 0.033 0.543 1996 0.069 1.011 1997 0.058 1.026 1998 0.013 0.271 1999 0.054 0.895 2000 0.023 0.446 2001 0.004 0.217 2002 0.025 0.497 2003 0.032 0.300 2004 0.041 1.002 2005 0.030 0.298 2006 0.035 0.725 2007 0.070 1.236 2008 0.090 0.911 2009 0.044 0.597 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #4 Rank Predeveloped Mitigated 1 0.0942 1.2364 2 0.0902 1.0651 3 0.0700 1.0259 4 0.0689 1.0111 Woodbridge Bldg A & B 3/25/2020 1:15:29 PM Page 52 5 0.0647 1.0023 6 0.0576 0.9230 7 0.0567 0.9109 8 0.0540 0.8955 9 0.0510 0.8876 10 0.0482 0.8834 11 0.0457 0.8562 12 0.0451 0.8285 13 0.0443 0.7788 14 0.0438 0.7277 15 0.0411 0.7273 16 0.0404 0.7248 17 0.0400 0.6149 18 0.0360 0.6027 19 0.0351 0.5970 20 0.0348 0.5434 21 0.0327 0.5332 22 0.0322 0.5126 23 0.0322 0.4970 24 0.0318 0.4910 25 0.0315 0.4859 26 0.0295 0.4766 27 0.0292 0.4680 28 0.0289 0.4635 29 0.0278 0.4552 30 0.0259 0.4518 31 0.0253 0.4464 32 0.0251 0.4156 33 0.0249 0.4074 34 0.0249 0.3632 35 0.0247 0.3464 36 0.0244 0.3432 37 0.0238 0.3344 38 0.0233 0.3289 39 0.0228 0.3100 40 0.0227 0.3094 41 0.0219 0.3069 42 0.0219 0.3017 43 0.0215 0.2998 44 0.0211 0.2985 45 0.0204 0.2978 46 0.0204 0.2941 47 0.0201 0.2938 48 0.0199 0.2933 49 0.0194 0.2897 50 0.0191 0.2870 51 0.0183 0.2709 52 0.0178 0.2701 53 0.0165 0.2690 54 0.0154 0.2640 55 0.0130 0.2633 56 0.0123 0.2617 57 0.0116 0.2606 58 0.0115 0.2580 59 0.0077 0.2399 60 0.0041 0.2326 61 0.0028 0.2168 Woodbridge Bldg A & B 3/25/2020 1:15:30 PM Page 58 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. Woodbridge Bldg A & B 3/25/2020 1:15:30 PM Page 59 Appendix Predeveloped Schematic Woodbridge Bldg A & B 3/25/2020 1:15:30 PM Page 60 Mitigated Schematic Woodbridge Bldg A & B 3/25/2020 1:15:31 PM Page 77 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2020; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com Appendix C Earth Science + Technology Geotechnical Engineering Services Report Proposed Greenline Warehouse A Project Federal Way, Washington for IRG, LLC March 9, 2017 Geotechnical Engineering Services Report Proposed Greenline Warehouse A Project Federal Way, Washington for IRG, LLC March 9, 2017 1101 South Fawcett Avenue, Suite 200 Tacoma, Washington 98402 253.383.4940 March 9, 2017| Page i File No. 22247-001-02 Table of Contents INTRODUCTION ......................................................................................................................................................... 1 PROJECT DESCRIPTION ........................................................................................................................................... 1 SCOPE OF SERVICES ............................................................................................................................................... 1 SITE CONDITIONS ..................................................................................................................................................... 3 Surface Conditions............................................................................................................................................... 3 Mapped Geologic Conditions .............................................................................................................................. 3 Subsurface Conditions ........................................................................................................................................ 3 Groundwater ........................................................................................................................................................ 4 CONCLUSIONS AND RECOMMENDATIONS ............................................................................................................ 4 General ................................................................................................................................................................. 4 Site Development and Earthwork ....................................................................................................................... 5 General .......................................................................................................................................................... 5 Stripping and Clearing .................................................................................................................................. 5 Subgrade Evaluation ..................................................................................................................................... 6 Excavation ..................................................................................................................................................... 6 Excavation Support ....................................................................................................................................... 6 Wet Weather Recommendations ................................................................................................................. 7 Fill Materials ......................................................................................................................................................... 8 On-site Soils ................................................................................................................................................... 8 Select Granular Fill ........................................................................................................................................ 8 Pipe Bedding ................................................................................................................................................. 9 Crushed Rock ................................................................................................................................................ 9 Fill Placement and Compaction .......................................................................................................................... 9 General .......................................................................................................................................................... 9 Area Fills and Bases ...................................................................................................................................... 9 Building Pad Subgrade .............................................................................................................................. 10 Trench Backfill ............................................................................................................................................ 10 Temporary and Permanent Slopes .................................................................................................................. 10 Groundwater and Drainage Considerations .................................................................................................... 11 Seismic Design Considerations ........................................................................................................................ 11 2015 IBC Seismic Design .......................................................................................................................... 11 Foundation Support .......................................................................................................................................... 12 Shallow Foundations .................................................................................................................................. 12 Bearing Capacity ........................................................................................................................................ 12 Footing Subgrade Preparation .................................................................................................................. 12 Foundation Settlement .............................................................................................................................. 12 Lateral Resistance ..................................................................................................................................... 12 Building Pad and Floor Slabs .................................................................................................................... 13 Retaining Structures ......................................................................................................................................... 13 Pavement Recommendations .......................................................................................................................... 14 Pavement Design ....................................................................................................................................... 14 Stormwater Infiltration Evaluation ................................................................................................................... 15 March 9, 2017| Page ii File No. 22247-001-02 LIMITATIONS .......................................................................................................................................................... 15 LIST OF FIGURES Figure 1. Vicinity Map Figure 2. Site Plan Existing Conditions Figure 3. Site Plan Proposed Conditions Figure 4. Schematic Drawing Hillside Fill APPENDICES Appendix A. Field Explorations and Laboratory Testing Figure A-1 – Key to Exploration Logs Figures A-2 through A-7 – Logs of Borings Figures A-8 through A-20 – Logs of Test Pits Figures A-21 through A-24 – Sieve Analysis Results Appendix B. Report Limitations and Guidelines for Use March 9, 2017| Page 1 File No. 22247-001-02 INTRODUCTION This report presents the results of our geotechnical engineering services for the Proposed Greenline Warehouse A, to be located on a 19-acre parcel within the former Weyerhaeuser property in Federal Way, Washington. The proposed development site is bordered to the west by Weyerhaeuser Road, to the north and east by Weyerhaeuser Way, and to the south by forested ground. Figure 1 shows the site location. Figure 2 shows the approximate current layout of the site. The parcel is presently forested and mostly undeveloped. The site contains relatively flat ground in the east and west, separated by a low slope, which descends downward to the east. Two north-south oriented and one east-west oriented gravel-covered driveways/trails are located within the site. We understand that these features were access roads to a residential development that occupied the north part of the site until about 1978. Recently deposited fill soils and organic debris and concrete bunkers associated with a former landscaping operation are located in the east-central part of the site (Figure 2). PROJECT DESCRIPTION Our understanding of the proposed project is based on information provided by ESM, Inc. and our project meetings. The information includes a preliminary site plan dated February 17, 2017 and two preliminary design cross sections through the site. We completed a geotechnical study in June 2016 for a previously considered warehouse development (Victory) on this parcel. The proposed Victory warehouse was to cover about 314,000 square feet. This included a 239,000-square-foot by 60-foot-high bay area of freezer rack storage We understand that the currently proposed development will comprise a new warehouse, asphalt-concrete (AC) pavement and Portland cement concrete (PCC) pavement in parking and access areas. We understand the building will cover about 225,950 square feet and will be about 44 feet in vertical height. Parking for up to 264 vehicles is planned for the development. The proposed building footprint is located within the approximate north 2/3 of the previously considered Victory structure footprint. The final floor slab is planned to be at about Elevation 403 feet. This will require cuts of up to 10 feet in height on the west side and up to 11 feet of fill in the southeast corner of the building pad. Cuts and fills will also be required for the parking areas. We understand that 2H:1V (horizontal:vertical) cut slopes will be used to establish planned grade along the west site boundary. Similarly inclined fill slopes are planned for the east perimeter of the site. Structural retaining walls (maximum height of 8 feet) for fills are planned for the site entrance at the southeast project corner. The wall types had not been specified at the time of this report. The proposed Greenline Warehouse A project layout is shown in Figure 3. SCOPE OF SERVICES The purpose of our services is to provide geotechnical engineering recommendations for the planned development, based primarily on subsurface explorations completed for a previous study at the site. Our services have been provided in general accordance with the confirming agreement dated March 9, 2017. Specifically, GeoEngineers scope includes: March 9, 2017| Page 2 File No. 22247-001-02 1. Reviewing proposed Greenline project plans provided by the design team. This includes a proposed clearing and grading plan and site cross sections. 2. Comparing the Greenline project plans with the June 2016 Victory plans. 3. Performing a brief geologic reconnaissance to evaluate current (March 2017) surface conditions at accessible portions of the site. 4. Reviewing subsurface data from explorations completed by us during the Victory phase of the project. Logs of these explorations and laboratory data are attached to this report. 5. Describing site conditions based on our site observations, review of published maps/aerial photographs and laboratory test results, and on the subsurface soil and groundwater conditions encountered in the borings and test pits. 6. Developing recommendations for site preparation and earthwork based on the data and our understanding of the proposed site development. This includes an evaluation of the suitability of on- site soil for use as fill including structural fill beneath the building and pavement areas, and gradations criteria for imported fill. A discussion of possible adverse effects of weather on construction activities and suitability of on-site soil during wet weather conditions is also provided. 7. Providing recommendations for temporary and permanent slopes. 8. Providing recommendations for shallow foundation support, including footing size, allowable soil bearing pressure and estimated post-construction settlements. 9. Discussing footing construction considerations including excavation, bearing surface preparation, material requirements and compaction requirements. 10. Providing subgrade preparation recommendations and modulus of subgrade reaction for design of slabs-on-grade. 11. Evaluating lateral earth pressures for design of below-grade structures, such as, dock-high walls and stormwater vault walls. 12. Providing recommendations for seismic design in accordance with 2015 International Building Code (IBC) and local standards. This includes an assessment and discussion of liquefaction potential and estimated ground settlement, and a discussion of potential remedial measures, as applicable. 13. Providing recommendations for pavement subgrade preparation and AC pavement design sections for both automobile and truck traffic areas. 14. Discussing drainage considerations for construction based on the conditions encountered in our explorations. 15. Developing a preliminary opinion regarding feasibility of stormwater infiltration based on the soils encountered in our prior explorations. Our opinion is based on empirical relationships between the laboratory data and soil permeability and our experience. March 9, 2017| Page 3 File No. 22247-001-02 SITE CONDITIONS Surface Conditions The site occupies two relatively level areas, which are separated by a slope that descends downward to the east. The slope is located in the approximate center of the site and is oriented generally north to south. Existing ground surface ranges from about Elevation 419 feet in the northwest to about Elevation 380 feet in the southeast. The existing site layout is shown in Figure 2. The site is currently vegetated with a thick stand of second or third growth fir, cedar and deciduous trees with a moderate to thick understory of brush. Isolated small wetland areas are mapped in the east portion of the site, in a general north-south line, as shown in Figure 2. We observed evidence of a north-south oriented drainage in the area of the wetlands during our site visits. Surface water was not observed in the drainage areas during our April-May 2016 site visits. We observed surface water in some of these areas during our March 2017 site reconnaissance. We observed dark, organic-rich soils exposed at the ground surface within the wetland and drainage areas at the time of our site visits. Stockpiles of soil fill, organic materials and concrete bunkers associated with a former landscaping operation were observed in the east-central portion of the site. The fill soils appeared to have been end- dumped from dump trucks. Evidence of older fill stockpiles were also observed in this area. We observed remnants of downed trees in this area during our March 2017 site reconnaissance. The approximate location and extent of these features are shown in Figure 2. Former residential street access roads were observed at the site, as also shown in Figure 2. The roadways appeared to be surfaced in gravel, however, it also appeared that asphalt-concrete pavement underlies the gravel in some places. We understand that a residential development occupied the north part of the site from between 1943 and about 1978, based on a review of aerial photos. Mapped Geologic Conditions General geologic conditions in the site vicinity were evaluated by reviewing “Geologic Map of the Poverty Bay 7.5 Minute Quadrangle, King and Pierce Counties, Washington, 2004” prepared for the United States Geological Survey (USGS). Native geologic materials mapped at and in the site vicinity consist of Vashon- age Glacial Till (map symbol Qvt). Vashon till was deposited by and directly beneath the advancing Vashon- age glacier as it moved south through the site area. The deposit typically consists of a dense to very dense mixture of silt, sand, gravel, cobbles and some boulders. Subsurface Conditions Six borings and 16 test pit explorations were completed at the site between May 24 through May 27, 2016 as part of our study for the originally planned Victory development concept. Additional explorations were not considered necessary based on the proposed location of the Greenline Warehouse, relative to the previously completed borings/test pits. Details of the field exploration and laboratory testing programs completed for the previous Victory development study are summarized in Appendix A. The exploration logs and results of the laboratory testing program are also presented in Appendix A. The approximate locations of all the explorations are shown in Figures 2 and 3. March 9, 2017| Page 4 File No. 22247-001-02 Fill, consisting of brown to black silty sand with wood and plastic debris was encountered in test pit TP-13 to a depth of about 5.5 feet. A thin layer of gravel fill was encountered at ground surface in borings B-3, B-4 and B-5 to a depth of 1.5 to 2 feet. Varying thicknesses of forest duff and/or topsoil and sod were encountered from ground surface in the other explorations. The organic material/duff layer ranged from about 6 inches to about 2.5 feet thick in the explorations. All explorations encountered and were terminated in glacial deposits. Dense to very dense glacial till was encountered beneath loose to dense or medium stiff to stiff weathered till and/or fill in the explorations. The unweathered glacial till, where present, was encountered to depths ranging from about 2.5 feet to about 8 feet below existing ground surface (bgs) in the explorations. The glacial till deposits typically consist of a mixture of silty gravel and silty sand with varying amounts of gravel and occasional cobbles and boulders. Layers or lenses of stiff to hard silt with sand and gravel are occasionally present within the weathered and unweathered glacial till at some locations. Laboratory testing on select samples of the glacial soils yielded fines contents (material passing the U.S. #200 sieve) ranging from 18 to 72 percent. In-place moisture contents ranged from 6 to 35 percent. Groundwater Groundwater was observed in B-1, B-2, B-3, and B-6 at depths ranging between about 6 feet and 19 feet bgs. Minor groundwater seepage was observed in TP-3, TP-7, TP-8 and TP-9 at depths ranging between about 1.5 and 10 feet bgs. A seasonal, perched groundwater table often forms in glacial deposits. Based on the site geologic conditions, our experience and recent observations, we expect groundwater seepage amounts and the depths at which it occurs will vary with season and precipitation. Larger zones of perched groundwater should be expected/ anticipated during the wetter winter and early spring months. CONCLUSIONS AND RECOMMENDATIONS General Based on the results of our subsurface exploration and testing program, it is our opinion that the site is suitable for the proposed development. A summary of the primary geotechnical considerations for the proposed warehouse facility is provided below. The summary is presented for introductory purposes only and should be used in conjunction with the detailed recommendations presented in this report. ■ The native soils contain a moderate to high percentage of fines and are very sensitive to small changes in moisture content. These soils are susceptible to disturbance from construction traffic when the moisture content is more than a few percent above the optimum moisture content for compaction. These soils will be difficult, if not impossible, to work or compact when wet or if earthwork is performed in wet weather. Therefore, it is more economical to perform earthwork during the normally drier periods of the year. Moisture conditioning of site soils will be required in order to obtain the required compaction. ■ We anticipate that the native soils and existing site fill will only be suitable for use as structural fill during extended periods of dry weather. We recommend imported granular soils be used for structural fill if construction occurs during periods of wet weather. March 9, 2017| Page 5 File No. 22247-001-02 ■ Some cutting and filling is planned to establish site grades. We recommend graded areas be protected before the onset of rainy weather because of the highly moisture sensitive character of much of the on- site soil. ■ We recommend constructing temporary haul roads underlain by quarry spalls or coarse crushed ballast material to help protect subgrades from disturbance and degradation under construction traffic. ■ The proposed warehouse structure may be satisfactorily supported on continuous and isolated shallow foundations supported on native soils or compacted structural fill that extends to undisturbed native soil. We recommend a maximum allowable soil bearing pressure of 4,000 pounds per square foot (psf) for design of footings. ■ Floor slabs may be supported on-grade. We recommend floor slabs be underlain by a capillary break layer consisting of a 4-inch thickness of well-graded sand and gravel or crushed rock with a maximum particle size of 3/4 inch and less than 5 percent fines (portion passing the U.S. Standard #200 sieve). Site Development and Earthwork General Site development work will include removing existing trees and vegetation, stripping of forest duff, topsoil and root layer, cutting in the west part of the site and placing fill in the east/southeast portions of the site to achieve a level building pad. The site soils are highly moisture sensitive due to high fines content. Grading and reuse of the on-site soils is more practical during the dry season (typically July through September). Moisture conditioning necessary to obtain proper compaction of on-site soil will likely not be practical during the cooler and wetter winter months, and may still present challenges during the normally dry summer months. We recommend a contingency be included in the project budget and schedule for export of unsuitable wet on-site soil and import of select granular soil if earthwork will be performed during periods of wet weather, which normally occurs in the winter months. The following sections provide our recommendations for earthwork, site development, and fill materials. Stripping and Clearing The existing trees, shrubs, topsoil, unsuitable native soils and unsuitable fill soils should be stripped and removed from all proposed building and pavement areas. Based on our explorations, the depth of stripping to remove unsuitable surface organic materials should generally vary between 6 and 24 inches. Greater stripping depths will be required to remove localized zones of loose or organic rich soil and tree roots. The primary roots systems for trees and shrubs should be completely removed. Required stripping depths should be evaluated based on observations during the stripping operation. Stripped organic material should be transported off site for disposal or processed and used as fill in landscaping areas. Unsuitable existing fill materials were encountered in some of our explorations. Unsuitable fills should be anticipated in the north part of the site where residential development formerly existed. The contractor could encounter debris, septic tanks and other unsuitable materials in these areas. We recommend that these materials be removed. The contractor might also encounter domestic water wells in this area and should be prepared to abandon these features in accordance with Washington State Department of Ecology (Ecology) regulations. March 9, 2017| Page 6 File No. 22247-001-02 Unsuitable organic-rich native soils should be expected in wetland areas and within the drainage area within the east part of the site. These soils may contain a high percentage of organic materials and must be removed where present in areas of the site where fills, pavements or structures are planned. The stockpiled fill soils and organic-rich materials within the landscape materials storage area should also be removed from the site. Asphalt concrete within existing trail areas should also be removed. Abandoned subgrade utilities beneath these trail areas should be anticipated and removed as necessary. Subgrade Evaluation After stripping, and excavation to planned subgrade is complete we recommend the exposed soil be proofrolled or probed and then compacted to a firm and unyielding condition. If dry weather conditions persist, we recommend that the subgrade be evaluated by proofrolling with a loaded dump truck or similar heavy rubber-tired construction equipment to identify soft, loose or unsuitable areas. Proofrolling must be conducted prior to placing fill. If the subgrade is prepared during or exposed to wet weather, we recommend that it be evaluated by probing with a steel probe rod. The proofrolling/probing should be observed by a qualified geotechnical engineer, who will evaluate the suitability of the subgrade and identify any areas of yielding, which are indicative of soft or loose soil. If soft or otherwise unsuitable areas revealed during proofrolling cannot be compacted to a stable and uniformly firm condition, we recommend that: (1) the subgrade soils be scarified (e.g., with a ripper or a farmer’s disc), aerated and recompacted; or (2) the unsuitable soils be excavated to firm soil and replaced with structural fill, as recommended by the geotechnical engineer. Excavation We anticipate large dozers with rippers may be required for mass grading where the subgrade comprises unweathered glacial till. Conventional earthmoving equipment in proper working order should be capable of making necessary excavations for utilities and footings. We recommend that footing and trench excavations be performed using a smooth-blade bucket to prevent excessive disturbance of the excavation base. Boulders and large cobbles are often present in glacial till deposits in the area and will likely be encountered during grading and/or utility excavations. Accordingly, the contractor should be prepared to remove boulders, if encountered. Boulders may be removed from the site or buried in landscape areas. Voids caused by boulder removal must be backfilled with structural fill. Excavation Support Shallow excavations (4 feet or less) in dense glacial deposits should stand at near vertical inclinations, provided groundwater seepage is not present in the cut face. Excavations deeper than 4 feet must be shored or laid back at a stable slope if workers are required to enter. Shoring for utility excavations must conform with the provisions of Title 296 Washington Administrative Code (WAC), Part N, “Excavation, Trenching and Shoring.” Regardless of the soil type encountered in the excavation, shoring, trench boxes or sloped sidewalls will be required under Washington Industrial Safety and Health Act (WISHA). While this report describes certain approaches to excavation and dewatering, the contract documents should specify that the contractor is responsible for selecting excavation and March 9, 2017| Page 7 File No. 22247-001-02 dewatering methods, monitoring the excavations for safety and providing shoring, as required, to protect personnel and adjacent structures. Wet Weather Recommendations Trafficability of the on-site soils will be severely limited during wet weather, or if the subgrade moisture content is more than a few percentage points above optimum. When wet, the on-site soils are susceptible to disturbance and generally will not provide adequate support for construction equipment. The on-site soils will be difficult, if not impossible, to adequately work or compact during periods of wet weather. Site Grading If site grading and fill placement occurs during wet weather conditions the following recommendations should be included in the development plan. Stripping and site preparation should be accomplished using track-mounted equipment and subgrade protection measures should be used. For example, a track- mounted excavator equipped with a smooth-edged bucket could be used working from a developed surface or a granular pad and loading into trucks supported on granular haul roads or working outward from the stripped surface. If the site subgrade is wet, it should be evaluated by probing with a steel rod, rather than by proofrolling. Soil that is disturbed during site preparation activities during wet conditions, as well as soft or loose zones identified during probing, should be removed and replaced with compacted structural fill. Granular Haul Roads and Working Blankets Wet weather construction in the silty native or fill soils will require granular haul roads and granular pads under the building structures to protect the subgrade. If the pavement areas are constructed during wet weather, they will also require a granular working blanket. The use of granular haul roads will be necessary for support of construction traffic during the rainy season (typically from October through June). Based on our experience, 18 to 24 inches of sand and gravel (which could be gravel base or fill material), crushed rock or quarry spalls with little to no fines will be necessary to provide support for construction equipment. Use of a geotextile fabric can reduce mixing of the subgrade and road support materials. It also may reduce the thickness of surfacing required. If gravel base material is used, the temporary roads could be constructed above the finished subgrades and extra material bladed onto other areas of the site when the roads are no longer necessary. Wet-Weather Fill We recommend fill placed during wet weather be select granular fill (pit run) or crushed rock as described in the “Fill Materials” section of this report. Erosion and Sedimentation Control The site will be susceptible to erosion during wet weather conditions, particularly if large segments of exposed subgrades are exposed to rainfall. Development, implementation and adherence to an Erosion and Sedimentation Control Plan should reduce the project impact on erosion-prone areas. The Plan should be designed in accordance with applicable city, county and/or state standards. The Plan should incorporate basic planning principles, including: ■ Scheduling grading and construction to reduce soil exposure. ■ Re-vegetating or mulching denuded areas. ■ Directing runoff away from exposed soils. March 9, 2017| Page 8 File No. 22247-001-02 ■ Reducing the length and steepness of slopes with exposed soils. ■ Decreasing runoff velocities. ■ Preparing drainage ways and outlets to handle concentrated or increased runoff. ■ Confining sediment to the project site. ■ Inspecting and maintaining control measures frequently. Some sloughing erosion and raveling of exposed or disturbed soil on slopes should be expected, particularly if the work is completed during the wet season. We recommend that disturbed soil be restored promptly so that surface runoff does not become channeled. Temporary erosion protection should be used and maintained in areas with exposed or disturbed soils to help reduce erosion and transport of sediment to adjacent areas and receiving waters. Permanent erosion protection should be provided by paving, structure construction or landscape planting. Until the permanent erosion protection is established and the site is stabilized, site monitoring may be required by qualified personnel who will evaluate the effectiveness of the erosion control measures and recommend repairs and/or modifications as appropriate. Provision for modifications to the erosion control system based on monitoring observations should be included in the Erosion and Sedimentation Control Plan. Fill Materials The workability of material used as structural fill depends on the gradation and moisture content of the soil. As the amount of fines (material passing the U.S. #200 sieve) increases, soil becomes increasingly sensitive to small changes in moisture content and adequate compaction becomes more difficult, if not impossible to achieve. We recommend that select granular fill or crushed rock be used as structural fill during the rainy season. The following paragraphs summarize the material requirements for fill and backfill. On-site Soils The native glacial till soils may be considered for use as structural fill during periods of extended dry weather, provided they can be properly moisture conditioned. The native soils may require moisture conditioning even during dry weather conditions. The on-site soils will be difficult, if not impossible, to work or adequately compact during periods of wet weather or if the in-place moisture condition of these soils is over optimum. On-site materials used as structural fill must be free of roots, organic matter and other deleterious materials and particles larger than 3 inches in diameter. Select Granular Fill Select granular fill (pit run) must consist of imported well-graded sand, sandy gravel, or crushed rock with a maximum particle size of 3 inches and less than 5 percent passing a U.S. #200 sieve. Organic matter, debris, or other deleterious material must not be present. Granular fill used during periods of prolonged dry weather may have up to 12 percent passing a U.S. #200 sieve. March 9, 2017| Page 9 File No. 22247-001-02 Pipe Bedding Trench backfill for the bedding and pipe zone must consist of well-graded granular material with a maximum particle size of 3/4 inch and less than 5 percent passing the U.S. #200 sieve. The material must be free of roots, debris, organic matter, and other deleterious material. Crushed Rock Crushed rock fill must consist of clean, durable, crushed angular rock that has a maximum particle size of 4 inches, is well graded between coarse and fine sizes, and has less than 5 percent fines (material finer than a U.S. #200 sieve). A smaller maximum particle size will be required for some applications as discussed in other sections of this report. Gravel materials should be crushed to have at least two fractured faces. Organic matter, debris, or other deleterious material must not be present. Fill Placement and Compaction General Fill soils should be compacted at a moisture content near optimum. The maximum allowable moisture content varies with the soil gradation, and should be evaluated during construction. Clayey soils and other fine granular soils may be difficult or impossible to compact during persistent wet conditions. Fill and backfill material should be placed in uniform, horizontal lifts, and uniformly densified with vibratory compaction equipment. The maximum lift thickness will vary depending on the material and compaction equipment used, but should generally not exceed 10 inches in loose thickness. We recommend that density testing of the placed structural fill be completed by a qualified geotechnical engineer to check that the structural fill compaction requirements presented in this report are achieved. Relatively thin lifts will likely be required to adequately compact excavated native material, if used for structural fill. Loose-lift thicknesses on the order of 3 to 4 inches should be expected to adequately compact the native materials. Thicker lifts can generally be used when the structural fill comprises select granular fill as described earlier in this report. Area Fills and Bases General Fill placed to raise site grades and aggregate base materials under foundations, slabs, and pavements should be placed on a prepared subgrade that consists of firm, inorganic native soils or compacted fill. Fill must be compacted to at least 95 percent of the maximum dry density (MDD) determined by ASTM International (ASTM) Test Method D 1557 (modified Proctor). During wet weather or in areas that are particularly sensitive to subgrade disturbance, we recommend placing a woven geotextile between the subgrade and the first lift of fill. For this application, the first lift must comprise select granular fill. We recommend a 10-inch lift thickness and densification by static rolling for the initial lift. Slope Fill Placement Based on our review of preliminary grading plans, it appears that earth fills are to be placed on the eastern portion of property on and adjacent to slopes inclined up to about 15 percent. The east and southeast March 9, 2017| Page 10 File No. 22247-001-02 portions of the proposed structure will be supported by the earth fill. The fill material should be placed and compacted using hillside grading techniques, as provided below. It is critical that the constructed fill is benched into the existing slope face. Bench excavations should be level and extend into the slope face until a vertical step of about 3 feet is constructed. The upper 1- to 3-foot thick layer of organic soil beneath the existing slope face should be removed and wasted. The remaining soil excavated from each bench can be spread into the next lift of structural fill. A typical cross- sectional drawing of slope fill is shown on Figure 4. Building Pad Subgrade The building pad will transition from cut to fill. In order to limit differential settlement to within 1/2 inch in 50 feet and provide uniform slab support we recommend the upper 1 foot of the pad subgrade be constructed with select import fill (granular soil with less than 5 percent fines). The select granular fill must be underlain by properly compacted on-site soil or undisturbed native soil prepared as recommended herein. Trench Backfill Backfill in the bedding and pipe zone should be compacted to 90 percent of the MDD as determined by ASTM Test Method D 1557, or as recommended by the pipe manufacturer. In nonstructural areas, trench backfill above the pipe zone should be compacted to at least 85 percent of the MDD as determined by ASTM Test Method D 1557. Suitable native soils or select granular soils should be acceptable in non-structural areas. Within structural areas, trench backfill placed above the pipe zone must be compacted to at least 92 percent of the MDD as determined by ASTM Test Method D 1557 at depths greater than 2 feet below the finished subgrade, and to 95 percent within 2 feet of finished subgrade. Trench backfill in structural areas should consist of select granular fill or crushed rock as described in the previous sections. Temporary and Permanent Slopes We recommend that permanent cut and fill slopes be inclined no steeper than 2H:1V. Flatter cut slopes may be necessary in areas where persistent groundwater seepage or zones of soft or loose soils are encountered. Temporary cut slopes should be inclined no steeper than about 1-1/2H:1V. Surface loads should be kept at a minimum distance of at least one-half the depth of the cut away from the top of temporary slopes. As previously stated, temporary cut slopes and shoring must comply with the provisions of Title 296 WAC, Part N, “Excavation, Trenching and Shoring.” The contractor performing the work must have the primary responsibility for protection of workmen and adjacent improvements, determining whether shoring is required, and for establishing the safe inclination for open-cut slopes. Fill slopes should be carefully compacted on the slope face. Alternatively, the fill embankment can be over- built and cut back to the design inclination. To reduce the potential for erosion, newly constructed slopes should be planted or hydroseeded shortly after completion of grading. Some sloughing and raveling of the slopes should be expected until the March 9, 2017| Page 11 File No. 22247-001-02 vegetation is established. This may require localized repairs and reseeding. Temporary covering, such as heavy plastic sheeting, jute fabric, loose straw, or excelsior matting should be used to protect unvegetated slopes during periods of rainfall. Groundwater and Drainage Considerations We recommend that pavement surfaces be sloped so that surface drainage flows away from the building. We recommend that all roof drains be collected in tightlines and routed into the storm drain system. Perched groundwater will likely develop on top of the very dense glacial till in unpaved areas during the rainy season. Seismic Design Considerations 2015 IBC Seismic Design General We recommend the parameters in Table 1 for use in seismic design in accordance with 2015 IBC. TABLE 1: SEISMIC DESIGN PARAMETERS 2015 IBC Seismic Design Parameters Spectral Response Acceleration at Short Periods (SS) 1.28g Spectral Response Acceleration at 1-Second Periods (S1) 0.49g Site Class C Design Peak Ground Acceleration (PGA) 0.50g Design Spectral Response Acceleration at Short Periods (SDS) 0.85g Design Spectral Response Acceleration at 1-Second Periods (SD1) 0.43g Liquefaction Potential Liquefaction refers to a condition where vibration or shaking of the ground, usually from earthquake forces, results in development of excess pore pressures in loose, saturated soils and subsequent loss of strength in the deposit of soil so affected. In general, soils that are susceptible to liquefaction include loose to medium dense sands to silty sands that are below the water table. Based on the soil type, and relative density of the soils encountered, it is our opinion that the potential for liquefaction at this site is low. Lateral Spreading Potential Lateral spreading related to seismic activity typically involves lateral displacement of large, surficial blocks of non-liquefied soil when a layer of underlying soil loses strength during seismic shaking. Lateral spreading usually develops in areas where sloping ground or large grade changes (including retaining walls) are present. Based on our understanding of the subsurface conditions and current site topography, it is our opinion that the risk of lateral spreading is low. Ground Rupture Because of the anticipated infrequent seismic event recurrence, the site location with respect to the nearest known active crustal faults and the presence of thick glacial deposits overlying bedrock, it is our opinion that the risk of ground rupture at the site due to crustal faulting is low. March 9, 2017| Page 12 File No. 22247-001-02 Foundation Support Shallow Foundations The proposed warehouse building can be supported on continuous wall or isolated column footings established on undisturbed native soils or structural fill placed over undisturbed native soils. Isolated column and continuous wall footings should have minimum widths of 24 and 18 inches, respectively. The exterior footings should be established at least 18 inches below the lowest adjacent grade. The recommended minimum footing depth is greater than the anticipated frost depth. Interior footings can be founded a minimum of 12 inches below the top of the floor slab. Bearing Capacity We recommend that footings founded as recommended be proportioned using a maximum allowable bearing pressure of 4,000 psf. This bearing pressure applies to the total of dead and long-term live loads and may be increased by one-third when considering earthquake or wind loads. This is a net bearing pressure. The weight of the footing and overlying backfill can be ignored in calculating footing sizes. Footing Subgrade Preparation Footing excavations should be performed using a smooth-edged bucket to limit bearing surface disturbance. Loose or disturbed materials present at the base of footing excavations should be removed or compacted. Foundation bearing surfaces should not be exposed to standing water. If water infiltrates and pools in the excavation, it must be removed and the bearing surface reevaluated before placing structural fill or reinforcing steel. We recommend that an experienced geotechnical engineer observe all foundation excavations before placing reinforcing steel in order to confirm that adequate bearing surfaces have been achieved and that the soil conditions are as anticipated. Unsuitable foundation subgrade soils must be removed and replaced with structural fill as recommended by the geotechnical engineer. It may be prudent to place a thin mud mat of lean concrete to protect the bearing surface if footing excavations are to remain open in wet weather. Foundation Settlement We estimate that settlements of footings designed and constructed as recommended will be less than 3/4 inch, for the anticipated loading conditions. Differential settlements between comparably loaded isolated column footings or along 50 feet of continuous footing will be less than 1/2 inch. Settlement is expected to occur rapidly as loads are applied Lateral Resistance The ability of the soil to resist lateral loads is a function of frictional resistance which can develop on the base of footings and slabs and the passive resistance which can develop on the face of below-grade elements of the structure as these elements tend to move into the soil. For footings and floor slabs founded in accordance with the recommendations presented above, the allowable frictional resistance may be computed using a coefficient of friction of 0.35 applied to vertical dead-load forces. The allowable passive resistance on the face of footings, grade beams or other embedded foundation elements may be computed using an equivalent fluid density of 300 pounds per cubic foot (pcf) for undisturbed on-site soils or structural March 9, 2017| Page 13 File No. 22247-001-02 fill extending out from the face of the foundation element a distance at least equal to two and one-half times the depth of the element. The passive earth pressure and friction components may be combined provided that the passive component does not exceed two-thirds of the total. The passive earth pressure value is based on the assumptions that the adjacent grade is level and that groundwater remains below the base of the footing throughout the year. The top foot of soil should be neglected when calculating passive lateral earth pressures unless the foundation area is covered with pavement or is inside a building. The lateral resistance values include a safety factor of approximately 1.5. Building Pad and Floor Slabs A modulus of subgrade reaction of 300 pounds per cubic inch (pci) can be used for designing the building floor slab provided that the subgrade consists of structural fill that has been prepared in accordance with the “Building Pad Subgrade” section. Settlements for the floor slab designed and constructed as recommended are estimated to be less than 3/4 inch for a floor load of 1,200 psf. We estimate that differential settlement of the floor slabs, will be 1/2 inch or less over a span of 50 feet providing that the fill below the slab is compacted as specified. The subgrade soils are non-expansive, so heave is not anticipated beneath the floor slab. We recommend that on-grade slabs be underlain by a minimum 4-inch-thick capillary break layer to reduce the potential for moisture migration into the slab. The capillary break material should consist of a well- graded sand and gravel or crushed rock with a maximum particle size of 3/4 inch and have less than 5 percent fines. The material should be placed as recommended in the “Fill Placement and Compaction” section. A vapor retarder should be used as necessary to control moisture penetration through the slab. This is especially important in areas where floor coverings, adhesives or tiles are planned. Retaining Structures Retaining structures for loading docks or other building walls that are free to rotate slightly around the base should be designed for active earth pressures using an equivalent fluid unit weight of 35 pcf. This value is based on the following assumptions: 1. The walls will not be restrained against rotation when the backfill is placed. 2. The backfill is level. 3. The backfill for a distance of at least 12 inches behind the wall consists of free-draining granular materials. 4. Hydrostatic pressures will be controlled by a back drain. If retaining walls are restrained against rotation during backfilling, they should be designed for an at-rest equivalent fluid unit weight of 55 pcf. Surcharge loads applied closer than one-half of the wall height should be considered as uniformly distributed horizontal pressures equal to one-third of the distributed vertical surcharge pressure. Footings for retaining walls should be designed as recommended for shallow foundations. March 9, 2017| Page 14 File No. 22247-001-02 Backfill should be placed and compacted as recommended in the “Fill Placement and Compaction” section of this report. The backfill should include drainage provisions to prevent hydrostatic pressures from developing behind walls. Measures should be taken to prevent overcompaction of the backfill behind the wall. This can be done by placing the zone of backfill located within 5 feet of the wall in lifts not exceeding 6 inches in loose thickness and compacting this zone with hand-operated equipment such as a vibrating plate compactor or jumping jack. Settlement of up to 1 percent of the wall height commonly occurs immediately adjacent to the wall as the wall rotates and develops active lateral earth pressures. Consequently, we recommend that flat work adjacent to retaining walls be postponed until settlement is complete. We understand that the fill walls on the east perimeter of the site will reach heights up to about 8 feet. Mechanically stabilized earth (MSE) retaining walls may be used for fill applications. However, structural foundations should not be located on the wall. They should be set back about 0.9h where h is the height of the wall. If on-site soil is used to construct the MSE wall, a friction angle of 27 degrees and a dry density of 125 pcf should be used in design. Higher strength values will result in excessive wall strain after construction. We understand that rockery retaining walls may be used to protect cuts in the west part of the site. If requested, GeoEngineers can assist in retaining wall selection and design once the grading plan is finalized. Pavement Recommendations Pavement Design General Based on our experience, we provide typical AC and PCC pavement sections below. These pavement sections are typical for commercial facilities in this area but may not be adequate for heavy construction traffic loads such as those imposed by concrete transit mixers, dump trucks or cranes or for unusual design traffic conditions. Additional pavement thickness may be necessary to prevent pavement damage during construction or if anticipated truck traffic for this facility is higher than typical. We can provide a specific design if detailed truck traffic loading information is provided. The recommended sections assume that final improvements surrounding the pavement will be designed and constructed such that stormwater or excess irrigation water from landscape areas does not accumulate below the pavement section or pond on pavement surfaces. Pavement subgrade must be prepared as previously described. Crushed surfacing base course and subbase must be moisture conditioned to near optimum moisture content and compacted to at least 95 percent of MDD (ASTM D 1577). Crushed surfacing base course must conform to applicable sections of 4-04 and 9-03.9(3) of the Washington State Department of Transportation (WSDOT) Standard Specifications. Hot mix asphalt must conform to applicable sections of 5-04, 9-02 and 9-03 of the WSDOT Standard Specifications. PCC must conform to applicable sections of 5-05, 9-01 and 9-03 of the WSDOT Standard Specifications Standard-Duty ACP – Automobile Driveways and Parking Areas ■ 2 inches of hot mix asphalt, class 1/2 inch, PG 58-22 ■ 4 inches of crushed surfacing base course March 9, 2017| Page 15 File No. 22247-001-02 ■ 6 inches of subbase consisting of select granular fill to provide uniform grading and pavement support, to maintain drainage, and to provide separation from fine-grained subgrade soil ■ Native subgrade or structural fill prepared in accordance with the “Site Development and Earthwork” section Heavy-Duty ACP – Areas Subject to Truck Traffic ■ 3 inches of hot mix asphalt, class 1/2 inch, PG 58-22 ■ 6 inches of crushed surfacing base course ■ 6 inches of subbase consisting of select granular fill to provide a uniform grading surface and pavement support, to maintain drainage, and to provide separation from fine-grained subgrade soil ■ Native subgrade or structural fill prepared accordance with the “Site Development and Earthwork” section PCC Pavement – Areas Subject to Heavy Truck Traffic ■ 6 inches of PCC pavement (28-day compressive strength of 6,000 pound per square inch [psi] and a modulus of rupture of 600 psi) ■ 6 inches of crushed surfacing base course ■ Native subgrade or structural fill prepared accordance with the “Site Development and Earthwork” section Stormwater Infiltration Evaluation As previously described the site soils generally consist of weathered till over unweathered till. Grain-size distribution analyses of these soils indicate fines contents ranging between about 18 and 72 percent. The unweathered till is typically in a dense to very dense condition and has very low permeability with respect to the vertical flow of water. Based on the soil gradation data, and our experience, it is our opinion there is very limited infiltration potential at this site. Because of these factors we recommend that stormwater detention be used for site development. LIMITATIONS We have prepared this geotechnical report for use by Federal Way Campus LLC and their agents for the Proposed Greenline Warehouse A project in Federal Way, Washington. The project agents may distribute copies of this report to authorized agents and regulatory agencies as may be required for the project. The intent of this report is to describe the subsurface conditions and provide a brief summary of the primary geotechnical considerations. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the field of geotechnical engineering in this area at the time this report was prepared. No warranty or other conditions express or implied should be understood. Please refer to Appendix B titled “Report Limitations and Guidelines for Use” for additional information pertaining to use of this report. µ SITE Vicinity Map Figure 1 Proposed Greenline Warehouse A Project Federal Way, Washington 2,000 2,0000 Feet Data Source: Mapbox Open Street Map, 2016 Notes: 1. The locations of all features shown are approximate. 2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. Projection: NAD 1983 UTM Zone 10N P:\22\22247001\GIS\MXDs\2224700102_F01_VM.mxd Date Exported: 03/08/17 by cchelf B-1B-2B-3B-4B-5B-6Test Pit 1Test Pit 2Test Pit 3Test Pit 4Test Pit 5Test Pit 6Test Pit 7Test Pit 8Test Pit 9Test Pit 10Test Pit 11Test Pit 12Test Pit 13B-6 TP-6 B-1 B-3 B-4 B-5 B-2 TP-5 TP-4 TP-13 TP-11 TP-10 TP-12 TP-3 TP-2 TP-1 TP-8 TP-7 TP-9 Figure 2 Proposed Greenline Warehouse A Project Federal Way, Washington P:\22\22247001\CAD\01\Geologic-Hydrogeologic Evaluation\2224700101_F02_Site Plan.dwg TAB:F02 Date Exported: 03/06/17 - 10:12 by hmaraSite Plan Existing Conditions WENSLegend Notes: 1. The locations of all features shown are approximate. 2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. Data Source: Background PDF from ESM Consulting Engineers, dated 05/05/16.Feet 0120 120 B-1 TP-1 Loop Road Weyerhaeuser Way S(Future Public Road)S 336th StreetBoring Number and Approximate Location Test Pit Number and Approximate Location Site Boundary Wetlands Mapped by Others Area of Soil Piles/ Organic Debris B-1B-2B-3B-4B-5B-6Test Pit 1Test Pit 2Test Pit 3Test Pit 4Test Pit 5Test Pit 6Test Pit 7Test Pit 8Test Pit 9Test Pit 10Test Pit 11Test Pit 12Test Pit 13B-6 TP-6 B-1 B-3 B-4 B-5 B-2 TP-5 TP-4 TP-13 TP-11 TP-10 TP-12 TP-3 TP-2 TP-1 TP-8 TP-7 TP-9 Figure 3 Proposed Greenline Warehouse A Project Federal Way, Washington Site Plan Proposed ConditionsW ENSFeet 0150 150 P:\22\22247001\CAD\01\Geologic-Hydrogeologic Evaluation\02224700101_F03_Site Plan Proposed Conditions.dwg TAB:F03 Date Exported: 03/01/17 - 18:15 by hmaraLegend Boring Number and Approximate Location Test Pit Number and Approximate Location Site Boundary Notes: 1. The locations of all features shown are approximate. 2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. Data Source: Base CAD files provided by ESM Consulting Engineers, dated 02/14/2017. Projection: WA State Plane, North Zone, NAD83, US Foot Proposed Greenline Warehouse A Water Quality and Detention Pond Loop Road Weyerhauser Way SWeyerhauser Way S Loop Road B-1 TP-1 Bench Drain Not to Scale Not to Scale Backfill: Freedraining Sand and/or Rock. Minimum 1' Enclosure of Pipe, Balance of Backfill Below Cap Should be Sand or Rock. Native Soil Cap Ground Surface 6"Ø Pipe HDPE or PVC Perforated Variable 2' Final Fill Surface Profile 8' MIN. Keyway Conceptual Arrangement of Bench Cuts Into Native Soil. If Seepage Encountered During Benching, Place Drain At This Location. Drain Detail is Shown Above. Native Building Subgrade Pre-development Ground Surface Fill Soil Native Soil Figure 4 P:\22\22247001\CAD\01\Geologic-Hydrogeologic Evaluation\2224700101_F04_Schematic Drawing Hillside Fill.dwg TAB:F4 Date Exported: 03/06/17 - 10:18 by hmaraSchematic Drawing Hillside Fill Notes: 1. The locations of all features shown are approximate. 2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. Data Source: Drawing created from sketch provided by GeoEngineers' personnel. Proposed Greenline Warehouse A Project Federal Way, Washington APPENDIX A Field Explorations and Laboratory Testing March 9, 2017| Page A-1 File No. 22247-001-02 APPENDIX A FIELD EXPLORATIONS AND LABORATORY TESTING Field Explorations Subsurface conditions at the site were previously explored by drilling a total of 6 borings and excavating 13 test pits. The explorations were completed between May 24 and 27, 2016. Borings were drilled to depths of 20 to 21.5 feet. Test pits were excavated to depths ranging from 8.5 to 11.5 feet below ground surface (bgs). The site explorations were continuously monitored by a member of GeoEngineers geotechnical staff. Our representative maintained a detailed log of the soils encountered, obtained soil samples and observed groundwater conditions. Figures 2 and 3 show the approximate locations of the explorations. Explorations were mapped using commercial-grade GPS equipment and should be considered accurate only to the extent implied by the method used. Soil samples were obtained from the borings using Standard Penetration Tests (SPTs) performed in general conformance with ASTM International (ASTM) Test Method D 1586. The sampler was driven with a 140-pound hammer falling 30 inches. The number of blows required to drive the sampler the last 12 inches or other indicated distance, into the soils is shown adjacent to the sample symbols on the boring logs. Disturbed samples were obtained from the split barrel for subsequent classification and index testing. Bulk soil samples from the test pits were collected directly from the trackhoe bucket and placed in plastic bags. Soils encountered in the borings were classified in the field in general accordance with ASTM Standard Practice D 2488, the Standard Practice for the Classification of Soils (Visual-Manual Procedure), which is described in Figure A-1. Soil classifications and sampling intervals are shown on the exploration logs. Inclined lines at the material contacts shown on the logs indicate uncertainty as to the exact contact elevation, rather than the inclination of the contact itself. Figures A-2 through A-20 present the exploration logs. Laboratory Testing Soil samples obtained from the explorations were brought to our laboratory to confirm field classifications. Selected samples were tested to determine their moisture content and grain-size distribution in general accordance with applicable ASTM standards. The moisture content of selected samples was determined in general accordance with ASTM Test Method D 2216. The test results are presented in the respective exploration logs in Appendix A. Grain-size distribution (sieve analyses) was conducted in general accordance with ASTM Test Method D 422. The results of the grain-size sieve analyses are presented in Figures A-21 through A-24. AC Cement ConcreteCC Asphalt Concrete No Visible Sheen Slight Sheen Moderate Sheen Heavy Sheen Not Tested NS SS MS HS NT ADDITIONAL MATERIAL SYMBOLS Measured groundwater level in exploration, well, or piezometer Measured free product in well or piezometer Graphic Log Contact Groundwater Contact Material Description Contact Laboratory / Field Tests Sheen Classification Sampler Symbol Descriptions NOTE: The reader must refer to the discussion in the report text and the logs of explorations for a proper understanding of subsurface conditions. Descriptions on the logs apply only at the specific exploration locations and at the time the explorations were made; they are not warranted to be representative of subsurface conditions at other locations or times. GRAPH Topsoil/ Forest Duff/Sod Crushed Rock/ Quarry Spalls FIGURE A-1 2.4-inch I.D. split barrel SYMBOLS TYPICAL KEY TO EXPLORATION LOGS CR DESCRIPTIONSLETTER TS GC PT OH CH MH OL GM GP GW DESCRIPTIONS TYPICAL LETTER (APPRECIABLE AMOUNT OF FINES) MAJOR DIVISIONS POORLY-GRADED SANDS, GRAVELLY SAND PEAT, HUMUS, SWAMP SOILS WITH HIGH ORGANIC CONTENTS CLEAN SANDS GRAVELS WITH FINES CLEAN GRAVELS HIGHLY ORGANIC SOILS SILTS AND CLAYS SILTS AND CLAYS SAND AND SANDY SOILS GRAVEL AND GRAVELLY SOILS (LITTLE OR NO FINES) FINE GRAINED SOILS COARSE GRAINED SOILS SW MORE THAN 50% OF COARSE FRACTION RETAINED ON NO. 4 SIEVE CL WELL-GRADED SANDS, GRAVELLY SANDS SILTY GRAVELS, GRAVEL - SAND - SILT MIXTURES LIQUID LIMIT GREATER THAN 50 SILTY SANDS, SAND - SILTMIXTURES (APPRECIABLE AMOUNT OF FINES) SOIL CLASSIFICATION CHART LIQUID LIMIT LESS THAN 50 SANDS WITH FINES SP (LITTLE OR NO FINES) ML SC SM NOTE: Multiple symbols are used to indicate borderline or dual soil classifications MORE THAN 50% OF COARSE FRACTION PASSING NO. 4 SIEVE CLAYEY GRAVELS, GRAVEL - SAND - CLAY MIXTURES CLAYEY SANDS, SAND - CLAY MIXTURES INORGANIC SILTS, ROCK FLOUR, CLAYEY SILTS WITH SLIGHT PLASTICITY ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS SILTY SOILS ORGANIC CLAYS AND SILTS OF MEDIUM TO HIGH PLASTICITY INORGANIC CLAYS OF HIGH PLASTICITY MORE THAN 50% PASSING NO. 200 SIEVE MORE THAN 50% RETAINED ON NO. 200 SIEVE WELL-GRADED GRAVELS, GRAVEL - SAND MIXTURES POORLY-GRADED GRAVELS,GRAVEL - SAND MIXTURES INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS GRAPH SYMBOLS Standard Penetration Test (SPT) Shelby tube Piston Direct-Push Bulk or grab Continuous Coring Distinct contact between soil strata Approximate contact between soil strata Contact between geologic units Contact between soil of the same geologic unit %F %G AL CA CP CS DS HA MC MD OC PM PI PP PPM SA TX UC VS Percent fines Percent gravel Atterberg limits Chemical analysis Laboratory compaction test Consolidation test Direct shear Hydrometer analysis Moisture content Moisture content and dry density Organic content Permeability or hydraulic conductivity Plasticity index Pocket penetrometer Parts per million Sieve analysis Triaxial compression Unconfined compression Vane shear Blowcount is recorded for driven samplers as the number of blows required to advance sampler 12 inches (or distance noted). See exploration log for hammer weight and drop. A "P" indicates sampler pushed using the weight of the drill rig. A "WOH" indicates sampler pushed using the weight of the hammer. Rev. 02/16 1 2 3 SA 4 5 4 18 10 17 18 74 54 43 50/4" 55 Dark brown silty fine to medium sand with gravel and organic matter (loose, moist) (weathered till) Gray silty sand with gravel (very dense, moist) (glacial till) Gray silty sand with gravel (dense to very dense, moist) (glacial till) Grades to very dense Brown/gray silt with sand, organic matter (wood fibers) and occasional gravel (hard, moist) SM SM SM ML Groundwater observed at approximately 18 feet during drilling 236 Total Depth (ft) Hammer Data System Datum Start End Checked By Logged By SWHDrilled Notes: CDL Surface Elevation (ft) Vertical Datum Driller Groundwater Depth to Water (ft)Date Measured Elevation (ft) Easting (X) Northing (Y) Track-Mounted L-10-1 Landa Holt Drilling Drilling Method Hollow-Stem Auger21.5 Autohammer 140 (lbs) / 30 (in) Drop Drilling Equipment 5/24/20165/24/2016 See Remarks 468 NAVD88 1277850.15 111995.64 WA State Plane,North NAD83 (feet) Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 20 IntervalElevation (feet)465460455450Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring B-1 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-2 Sheet 1 of 1Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_GEOTECH_STANDARD_%FREMARKS FinesContent (%)MoistureContent (%) 1 2 SA 3 SA 4 5 16 17 12 10 5 62 48 60 50/4" 100/5" Gray silty sand with occasional gravel (very dense, moist) (glacial till) Gray silty sand with gravel (dense to very dense, moist) (glacial till) Gray silty sand with gravel (very dense, moist) (glacial till) SM SM SM Water/moisture on sampler at approximately 5 feet during drilling Increasing amount of silt/fines Gravel stuck in sampler Groundwater observed at approximately 19 feet during drilling 42 32 11 10 Total Depth (ft) Hammer Data System Datum Start End Checked By Logged By SWHDrilled Notes: CDL Surface Elevation (ft) Vertical Datum Driller Groundwater Depth to Water (ft)Date Measured Elevation (ft) Easting (X) Northing (Y) Track-Mounted L-10-1 Landa Holt Drilling Drilling Method Hollow-Stem Auger20.8 Autohammer 140 (lbs) / 30 (in) Drop Drilling Equipment 5/24/20165/24/2016 See Remarks 448 NAVD88 1277673.44 112111.02 WA State Plane,North NAD83 (feet) Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 20 IntervalElevation (feet)445440435430Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring B-2 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-3 Sheet 1 of 1Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_GEOTECH_STANDARD_%FREMARKS FinesContent (%)MoistureContent (%) 1 SA 2 3 SA 4 5 14 10 12 8 8 42 54 39 50/4" 50/5" Brown gravel with cobbles (loose, moist) (fill) Brown/gray silty fine to medium sand with gravel (dense, moist) (weathered till) Gray silty fine to medium sand with gravel (dense to very dense, moist) (glacial till) Gray silty fine to medium sand with gravel (very dense, moist) (glacial till) GP SM SM SM Possible cobbles Possible groundwater observed at approximately 9½ feet during drilling 30 35 9 9 Total Depth (ft) Hammer Data System Datum Start End Checked By Logged By SWHDrilled Notes: CDL Surface Elevation (ft) Vertical Datum Driller Groundwater Depth to Water (ft)Date Measured Elevation (ft) Easting (X) Northing (Y) Track-Mounted L-10-1 Landa Holt Drilling Drilling Method Hollow-Stem Auger20.9 Autohammer 140 (lbs) / 30 (in) Drop Drilling Equipment 5/24/20165/24/2016 See Remarks 464 NAVD88 1277734.72 111818.94 WA State Plane,North NAD83 (feet) Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 20 IntervalElevation (feet)460455450445Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring B-3 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-4 Sheet 1 of 1Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_GEOTECH_STANDARD_%FREMARKS FinesContent (%)MoistureContent (%) 1 2 SA 3 4 5 16 12 18 18 5 36 52 28 53 65/6" Brown gravel with cobbles (loose, moist) (fill) Gray silty sand with gravel (dense, moist) (weathered till) Gray silty sand with gravel (medium dense to very dense, moist) (glacial till) Grades to medium dense Grades to moist Gray silty fine sand with gravel and fractured cobble (very dense, moist) GP SM SM SM Possible groundwater observed at 5 feet Gravel in end of sampler Hard drilling at approximately 19 feet; possible cobbles/boulder 4212 Total Depth (ft) Hammer Data System Datum Start End Checked By Logged By SWHDrilled Notes: CDL Surface Elevation (ft) Vertical Datum Driller Groundwater Depth to Water (ft)Date Measured Elevation (ft) Easting (X) Northing (Y) Track-Mounted L-10-1 Landa Holt Drilling Drilling Method Hollow-Stem Auger20.5 Autohammer 140 (lbs) / 30 (in) Drop Drilling Equipment 5/25/20165/25/2016 See Remarks 474 NAVD88 1277753.63 111713.67 WA State Plane,North NAD83 (feet) Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 20 IntervalElevation (feet)470465460455Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring B-4 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-5 Sheet 1 of 1Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_GEOTECH_STANDARD_%FREMARKS FinesContent (%)MoistureContent (%) 1 SA 2 3 4 5 14 6 18 9 10 59 50/4" 64 50/5" 100/10" Gray gravel with organics (loose, moist) (fill) Gray silty sand with occasional gravel (very dense, moist) (glacial till) Gray silty gravel with sand (very dense, moist) (glacial till) Gray silty fine to medium sand with gravel (very dense, moist) (glacial till) GP SM GM SM Possible cobbles Gravel in end of sampler Possible cobbles 37 39 7 8 Total Depth (ft) Hammer Data System Datum Start End Checked By Logged By SWHDrilled Notes: CDL Surface Elevation (ft) Vertical Datum Driller Groundwater Depth to Water (ft)Date Measured Elevation (ft) Easting (X) Northing (Y) Track-Mounted L-10-1 Landa Holt Drilling Drilling Method Hollow-Stem Auger21 Autohammer 140 (lbs) / 30 (in) Drop Drilling Equipment 5/25/20165/25/2016 See Remarks 472 NAVD88 1277676.09 111517.75 WA State Plane,North NAD83 (feet) Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 20 IntervalElevation (feet)470465460455Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring B-5 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-6 Sheet 1 of 1Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_GEOTECH_STANDARD_%FREMARKS FinesContent (%)MoistureContent (%) 1 2 3 4 5 0 14 18 9 10 13 29 83 50/3" 75/4" Gray silt with sand, gravel and organic matter (topsoil?) Gray silty sand with gravel and organics (medium dense, moist) (weathered till) Gray silty gravel with sand (medium dense, wet) (weathered till/outwash) Gray silty fine to coarse sand with gravel (very dense, wet) (glacial till) TS SM GM SM No recovery Harder drilling below 5 feet Groundwater encountered at approximately 6 feet during drilling Hard drilling at 13 feet Total Depth (ft) Hammer Data System Datum Start End Checked By Logged By SWHDrilled Notes: CDL Surface Elevation (ft) Vertical Datum Driller Groundwater Depth to Water (ft)Date Measured Elevation (ft) Easting (X) Northing (Y) Track-Mounted L-10-1 Landa Holt Drilling Drilling Method Hollow-Stem Auger20.8 Autohammer 140 (lbs) / 30 (in) Drop Drilling Equipment 5/25/20165/25/2016 See Remarks 410 NAVD88 1278027.56 111879.51 WA State Plane,North NAD83 (feet) Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 20 IntervalElevation (feet)405400395390Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring B-6 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-7 Sheet 1 of 1Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_GEOTECH_STANDARD_%FREMARKS FinesContent (%)MoistureContent (%) 1 SA 2 3 4 ML SM Brown sandy silt with gravel and organic matter (roots down to 2 feet) (medium stiff, moist) (weathered till) Gray/brown silty sand with gravel and cobbles (dense, moist) (glacial till) Becoming moist to wet at 10½ feet; no visible water Test pit completed at 11½ feet No groundwater seepage observed No caving observed 20 55 Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-1 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-8 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/26/2016 Track Excavator Total Depth (ft) CDL 11.5 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 9 10 11 SAMPLE Graphic LogElevation (feet)472471470469468467466465464463462Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 1 2 3 4 SA SM SM GM Brown silty sand with gravel, roots and organic matter (fill) (loose, moist) Brown-gray silty sand with gravel and cobbles (weathered till) (medium dense, moist) Gray silty gravel with sand and cobbles (dense to very dense, moist) (glacial till) Pockets of silt with sand and gravel; large cobbles (dense) Test pit completed at 11 feet No groundwater seepage observed No caving observed 10 30 Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-2 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-9 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/26/2016 Track Excavator Total Depth (ft) CDL 11.0 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 9 10 11 SAMPLE Graphic LogElevation (feet)470469468467466465464463462461460Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 1 2 #200 Wash 3 4 TS SM ML ML ML 6 inches topsoil/forest duff Brown silty sand with gravel (pockets of silt) (loose to medium dense, moist) (weathered till) Brown silt with sand (stiff, moist) (glacial till) Brown/gray silt (stiff, moist) (glacial till) Brown/gray silty fine to coarse sand with gravel and cobbles (hard, moist to wet) (glacial till) Test pit completed at 8½ feet Slow groundwater seepage at 7 feet No caving observed Roots at 2 feet1272 Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-3 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-10 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/26/2016 Track Excavator Total Depth (ft) CDL 8.5 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 SAMPLE Graphic LogElevation (feet)406405404403402401400399Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 1 2 3 4 SA TS SM GM Topsoil/roots/forest duff Brown silty sand with gravel (medium dense, moist) (fill) Gray/brown silty gravel with sand and cobbles (dense to very dense, moist) (glacial till) Becomesg moist to wet at 8 feet Test pit completed at 11 feet No groundwater seepage observed No caving observed Metal pipe observed in pit sidewall Roots to 2 feet 9 20 Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-4 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-11 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/26/2016 Track Excavator Total Depth (ft) CDL 11.0 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 9 10 11 SAMPLE Graphic LogElevation (feet)430429428427426425424423422421420Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 1 2 3 SA 4 SM SM SM Brown-red silty sand with organic matter (coal/charcoal) (loose, moist) (topsoil) Brown silty sand with gravel and cobbles (medium dense to dense, moist) (weathered till) Gray silty sand with gravel and cobbles (dense to very dense, moist) (glacial till) Test pit completed at 11 feet No groundwater seepage observed No caving observed Roots to 1½ feet 9 18 Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-5 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-12 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/26/2016 Track Excavator Total Depth (ft) CDL 11.0 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 9 10 11 SAMPLE Graphic LogElevation (feet)414413412411410409408407406405404Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 1 2 3 4 TS SM SM Brown silty sand with organic matter (roots) (loose, medium dense, moist) (forest duff/topsoil) Brown silty sand with gravel and cobbles (medium dense to dense, moist) (weathered till) Gray silty sand with gravel and occasional cobbles (dense to very dense, moist to wet) (glacial till) Test pit completed at 11 feet No groundwater seepage observed No caving observed Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-6 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-13 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/26/2016 Track Excavator Total Depth (ft) CDL 11.0 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 9 10 11 SAMPLE Graphic LogElevation (feet)418417416415414413412411410409408Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 1 2 3 -200 Wash TS GP-GM ML GM Topsoil/roots (forest duff) Brown sandy gravel with silt (medium dense to dense, moist to wet) (weathered till) Brown/gray silt with sand and gravel (stiff, moist) (glacial till) Gray silty gravel with sand (very dense, moist) (glacial till) Test pit completed at 11 feet Slow groundwater seepage observed at approximately 1½ feet Caving observed above 6 feet 35 67 Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-7 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-14 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/26/2016 Track Excavator Total Depth (ft) CDL 11.0 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 9 10 11 SAMPLE Graphic LogElevation (feet)452451450449448447446445444443442Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 1 2 3 SM/OH SM SM Dark brown silty sand and organic silt (loose/soft, moist) (forest duff) Brown silty sand with gravel and cobbles (medium dense to dense, moist) (weathered till/) Gray silty fine to coarse sand with gravel and occasional cobbles (very dense, moist to wet) (glacial till) Test pit completed at 11 feet Slow groundwater seepage observed at approximately 8½ feet No caving observed Wet at 8 feet Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-8 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-15 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/26/2016 Track Excavator Total Depth (ft) CDL 11.0 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 9 10 11 SAMPLE Graphic LogElevation (feet)450449448447446445444443442441440Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 1 2 3 SA 4 OH SM GM Brown organic silt and with sand (topsoil/forest duff) Brown silty sand with gravel (medium dense, moist) (weathered till) Gray silty gravel with sand (dense to very dense, moist to wet) (glacial till) Test pit completed at 11 feet Groundwater seepage observed at approximately 10 feet No caving observed Boulder at 2 feet Hard at 6 feet Gravel lenses 6 8 Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-9 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-16 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/27/2016 Track Excavator Total Depth (ft) CDL 11.0 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 9 10 11 SAMPLE Graphic LogElevation (feet)439438437436435434433432431430429Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 1 2 3 4 OH ML SM Organic silt with sand (medium stiff, moist) Orange/gray silt (stiff, moist) (glacial till) Gray silty sand with gravel (very dense, moist) (glacial till) Test pit completed at 11 feet No groundwater seepage observed No caving observed Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-10 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-17 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/27/2016 Track Excavator Total Depth (ft) CDL 11.0 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 9 10 11 SAMPLE Graphic LogElevation (feet)420419418417416415414413412411410Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 1 2 -200 Wash 3 TS SM SM Topsoil/forest duff, organic matter (roots) Brown silty fine sand with gravel and occasional organic matter/roots (medium dense, moist) (weathered till) Gray silty fine to medium sand with gravel and occasional cobbles (very dense, moist) (glacial til) Test pit completed at 11 feet No groundwater seepage observed No caving observed Metal pipe and electrical line at 1.5 feet 10 39 Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-11 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-18 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/27/2016 Track Excavator Total Depth (ft) CDL 11.0 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 9 10 11 SAMPLE Graphic LogElevation (feet)448447446445444443442441440439438Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 1 2 3 4 SOD SM ML SM Sod Brown silty sand, occasional gravel with organic matter (loose, moist) (topsoil) Brown/gray silt with sand and gravel (stiff, moist) (weathered till) Gray silty fine to medium sand with gravel (dense to very dense, moist) (glacial till) Test pit completed at 11½ feet No groundwater seepage observed No caving observed Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-12 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-19 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/27/2016 Track Excavator Total Depth (ft) CDL 11.5 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 9 10 11 SAMPLE Graphic LogElevation (feet)429428427426425424423422421420419Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 1 2 SA 3 4 SM SM SM SM Brown silty sand with gravel (dense, moist) (fill) Black silty sand with debris (wood/plastic infill) (dense, moist) (fill) Becomes brown Brown/gray silty sand with gravel (dense, moist) (weathered till) Gray silty sand with gravel (very dense, moist) (glacial till) Test pit completed at 11 feet No groundwater seepage observed No caving observed 28 50 Notes: See Figure A-1 for explanation of symbols. The depths on the test pit logs are based on an average of measurements across the test pit and should be considered accurate to 0.5 foot.Tacoma: Date:6/17/16 Path:P:\21\21644001\GINT\2164400100.GPJ DBTemplate/LibTemplate:GEOENGINEERS_DF_STD_US.GDT/GEI8_TESTPIT_1P_GEOTEC_%FLog of Test Pit TP-13 Proposed Victory Unlimited Project Federal Way, Washington 21644-001-00 Project: Project Location: Project Number:Figure A-20 Sheet 1 of 1 Date Excavated: Equipment: Logged By:5/27/2016 Track Excavator Total Depth (ft) CDL 11.0 Testing SampleDepth (feet)1 2 3 4 5 6 7 8 9 10 11 SAMPLE Graphic LogElevation (feet)406405404403402401400399398397396Sample NameTestingGroupClassificationEncountered WaterMATERIAL DESCRIPTION REMARKS MoistureContent (%)FinesContent (%)MoistureContent (%) 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.11101001000PERCENT PASSING BY WEIGHT GRAIN SIZE IN MILLIMETERS U.S. STANDARD SIEVE SIZE SAND SILT OR CLAYCOBBLESGRAVEL COARSE MEDIUM FINECOARSEFINE Exploration Number Depth (feet)Soil Description B-2 B-3 5 2.5 Silty sand with gravel (SM) Silty sand with gravel (SM) Symbol Moisture (%) 11 9 3/8”3”1.5”#4 #10 #20 #40 #60 #1003/4”Figure A-21Sieve Analysis Results21644-001-00 Date Exported: 06/03/16 Note:This report may not be reproduced,except in full,without written approval of GeoEngineers,Inc.Test results are applicable only to the specific sample on which they were performed,and should not be interpreted as representative of any other samples obtained at other times,depths or locations,or generated by separate operations or processes. The grain size analysis results were obtained in general accordance with ASTM D 6913. #200 Proposed Victory Unlimited ProjectFederal Way, Washington 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.11101001000PERCENT PASSING BY WEIGHT GRAIN SIZE IN MILLIMETERS U.S. STANDARD SIEVE SIZE SAND SILT OR CLAYCOBBLESGRAVEL COARSE MEDIUM FINECOARSEFINE Exploration Number Depth (feet)Soil Description B-3 B-4 B-5 B-5 10 5 3 10 Silty sand with gravel (SM) Silty sand with gravel (SM) Silty sand with gravel (SM) Silty gravel with sand (GM) Symbol Moisture (%) 9 12 7 9 3/8”3”1.5”#4 #10 #20 #40 #60 #1003/4”Figure A-22Sieve Analysis Results21644-001-00 Date Exported: 06/03/16 Note:This report may not be reproduced,except in full,without written approval of GeoEngineers,Inc.Test results are applicable only to the specific sample on which they were performed,and should not be interpreted as representative of any other samples obtained at other times,depths or locations,or generated by separate operations or processes. The grain size analysis results were obtained in general accordance with ASTM D 6913. #200 Proposed Victory Unlimited ProjectFederal Way, Washington 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.11101001000PERCENT PASSING BY WEIGHT GRAIN SIZE IN MILLIMETERS U.S. STANDARD SIEVE SIZE SAND SILT OR CLAYCOBBLESGRAVEL COARSE MEDIUM FINECOARSEFINE Exploration Number Depth (feet)Soil Description TP-1 TP-2 TP-4 TP-5 1.5 8 8 4 Sandy silt with gravel (ML) Silty gravel with sand (GM) Silty gravel with sand (GM) Silty sand with gravel (SM) Symbol Moisture (%) 20 10 9 9 3/8”3”1.5”#4 #10 #20 #40 #60 #1003/4”Figure A-23Sieve Analysis Results21644-001-00 Date Exported: 06/03/16 Note:This report may not be reproduced,except in full,without written approval of GeoEngineers,Inc.Test results are applicable only to the specific sample on which they were performed,and should not be interpreted as representative of any other samples obtained at other times,depths or locations,or generated by separate operations or processes. The grain size analysis results were obtained in general accordance with ASTM D 6913. #200 Proposed Victory Unlimited ProjectFederal Way, Washington 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.11101001000PERCENT PASSING BY WEIGHT GRAIN SIZE IN MILLIMETERS U.S. STANDARD SIEVE SIZE SAND SILT OR CLAYCOBBLESGRAVEL COARSE MEDIUM FINECOARSEFINE Exploration Number Depth (feet)Soil Description TP-9 TP-13 5 3 Silty gravel with sand (GM) Silty sand (SM) Symbol Moisture (%) 6 28 3/8”3”1.5”#4 #10 #20 #40 #60 #1003/4”Figure A-24Sieve Analysis Results21644-001-00 Date Exported: 06/03/16 Note:This report may not be reproduced,except in full,without written approval of GeoEngineers,Inc.Test results are applicable only to the specific sample on which they were performed,and should not be interpreted as representative of any other samples obtained at other times,depths or locations,or generated by separate operations or processes. The grain size analysis results were obtained in general accordance with ASTM D 6913. #200 Proposed Victory Unlimited ProjectFederal Way, Washington APPENDIX B Report Limitations and Guidelines for Use March 9, 2017| Page B-1 File No. 22247-001-02 APPENDIX B REPORT LIMITATIONS AND GUIDELINES FOR USE1 This appendix provides information to help you manage your risks with respect to the use of this report. Read These Provisions Closely It is important to recognize that the geoscience practices (geotechnical engineering, geology and environmental science) rely on professional judgment and opinion to a greater extent than other engineering and natural science disciplines, where more precise and/or readily observable data may exist. To help clients better understand how this difference pertains to our services, GeoEngineers includes the following explanatory “limitations” provisions in its reports. Please confer with GeoEngineers if you need to know more how these “Report Limitations and Guidelines for Use” apply to your project or site. Geotechnical Services are Performed for Specific Purposes, Persons and Projects This report has been prepared for Federal Way Campus LLC and for the Greenline Warehouse A project specifically identified in the report. The information contained herein is not applicable to other sites or projects. GeoEngineers structures its services to meet the specific needs of its clients. No party other than the party to whom this report is addressed may rely on the product of our services unless we agree to such reliance in advance and in writing. Within the limitations of the agreed scope of services for the Project, and its schedule and budget, our services have been executed in accordance with our Agreement with Federal Way Campus LLC dated March 9, 2017 and generally accepted geotechnical practices in this area at the time this report was prepared. We do not authorize, and will not be responsible for, the use of this report for any purposes or projects other than those identified in the report. A Geotechnical Engineering or Geologic Report is based on a Unique Set of Project-Specific Factors This report has been prepared for Proposed Federal Way Campus, Greenline Warehouse A project located in Federal Way, Washington. GeoEngineers considered a number of unique, project-specific factors when establishing the scope of services for this project and report. Unless GeoEngineers specifically indicates otherwise, it is important not to rely on this report if it was: ■ not prepared for you, ■ not prepared for your project, ■ not prepared for the specific site explored, or ■ completed before important project changes were made. For example, changes that can affect the applicability of this report include those that affect: ■ the function of the proposed structure; 1 Developed based on material provided by ASFE, Professional Firms Practicing in the Geosciences; www.asfe.org. March 9, 2017| Page B-2 File No. 22247-001-02 ■ elevation, configuration, location, orientation or weight of the proposed structure; ■ composition of the design team; or ■ project ownership. If changes occur after the date of this report, GeoEngineers cannot be responsible for any consequences of such changes in relation to this report unless we have been given the opportunity to review our interpretations and recommendations. Based on that review, we can provide written modifications or confirmation, as appropriate. Environmental Concerns are Not Covered Unless environmental services were specifically included in our scope of services, this report does not provide any environmental findings, conclusions, or recommendations, including but not limited to, the likelihood of encountering underground storage tanks or regulated contaminants. Subsurface Conditions Can Change This geotechnical or geologic report is based on conditions that existed at the time the study was performed. The findings and conclusions of this report may be affected by the passage of time, by man-made events such as construction on or adjacent to the site, new information or technology that becomes available subsequent to the report date, or by natural events such as floods, earthquakes, slope instability or groundwater fluctuations. If more than a few months have passed since issuance of our report or work product, or if any of the described events may have occurred, please contact GeoEngineers before applying this report for its intended purpose so that we may evaluate whether changed conditions affect the continued reliability or applicability of our conclusions and recommendations. Geotechnical and Geologic Findings are Professional Opinions Our interpretations of subsurface conditions are based on field observations from widely spaced sampling locations at the site. Site exploration identifies the specific subsurface conditions only at those points where subsurface tests are conducted or samples are taken. GeoEngineers reviewed field and laboratory data and then applied its professional judgment to render an informed opinion about subsurface conditions at other locations. Actual subsurface conditions may differ, sometimes significantly, from the opinions presented in this report. Our report, conclusions and interpretations are not a warranty of the actual subsurface conditions. Geotechnical Engineering Report Recommendations are Not Final We have developed the following recommendations based on data gathered from subsurface investigation(s). These investigations sample just a small percentage of a site to create a snapshot of the subsurface conditions elsewhere on the site. Such sampling on its own cannot provide a complete and accurate view of subsurface conditions for the entire site. Therefore, the recommendations included in this report are preliminary and should not be considered final. GeoEngineers’ recommendations can be finalized only by observing actual subsurface conditions revealed during construction. GeoEngineers cannot assume responsibility or liability for the recommendations in this report if we do not perform construction observation. March 9, 2017| Page B-3 File No. 22247-001-02 We recommend that you allow sufficient monitoring, testing and consultation during construction by GeoEngineers to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes if the conditions revealed during the work differ from those anticipated, and to evaluate whether earthwork activities are completed in accordance with our recommendations. Retaining GeoEngineers for construction observation for this project is the most effective means of managing the risks associated with unanticipated conditions. If another party performs field observation and confirms our expectations, the other party must take full responsibility for both the observations and recommendations. Please note, however, that another party would lack our project- specific knowledge and resources. A Geotechnical Engineering or Geologic Report Could Be Subject to Misinterpretation Misinterpretation of this report by members of the design team or by contractors can result in costly problems. GeoEngineers can help reduce the risks of misinterpretation by conferring with appropriate members of the design team after submitting the report, reviewing pertinent elements of the design team’s plans and specifications, participating in pre-bid and preconstruction conferences, and providing construction observation. Do Not Redraw the Exploration Logs Geotechnical engineers and geologists prepare final boring and testing logs based upon their interpretation of field logs and laboratory data. The logs included in a geotechnical engineering or geologic report should never be redrawn for inclusion in architectural or other design drawings. Photographic or electronic reproduction is acceptable, but separating logs from the report can create a risk of misinterpretation. Give Contractors a Complete Report and Guidance To help reduce the risk of problems associated with unanticipated subsurface conditions, GeoEngineers recommends giving contractors the complete geotechnical engineering or geologic report, including these “Report Limitations and Guidelines for Use.” When providing the report, you should preface it with a clearly written letter of transmittal that: ■ advises contractors that the report was not prepared for purposes of bid development and that its accuracy is limited; and ■ encourages contractors to confer with GeoEngineers and/or to conduct additional study to obtain the specific types of information they need or prefer. Contractors are Responsible for Site Safety on Their Own Construction Projects Our geotechnical recommendations are not intended to direct the contractor’s procedures, methods, schedule or management of the work site. The contractor is solely responsible for job site safety and for managing construction operations to minimize risks to on-site personnel and adjacent properties. March 9, 2017| Page B-4 File No. 22247-001-02 Biological Pollutants GeoEngineers’ Scope of Work specifically excludes the investigation, detection, prevention or assessment of the presence of Biological Pollutants. Accordingly, this report does not include any interpretations, recommendations, findings or conclusions regarding the detecting, assessing, preventing or abating of Biological Pollutants, and no conclusions or inferences should be drawn regarding Biological Pollutants as they may relate to this project. The term “Biological Pollutants” includes, but is not limited to, molds, fungi, spores, bacteria and viruses, and/or any of their byproducts. A Client that desires these specialized services is advised to obtain them from a consultant who offers services in this specialized field. Appendix D Appendix E MEMORANDUM TO:ANN DOWER, CITY OF FEDERAL WAY FROM: LAURA BARTENHAGEN RE:WOODBRIDGE BUILDING A TIR ADDENDUM JOB #:1886-001-016-0015 DATE: APRIL 22, 2020 On behalf of Federal Way Campus, LLC, ESM Consulting Engineers, LLC is providing the following supplemental information to demonstrate compliance and consistency with the 1991 Executive Proposed Basin Plan - Hylebos Creek and Lower Puget Sound (Basin Plan) for the Woodbridge Building A project. This supplemental information is provided to be in compliance with the SEPA MDNS Condition #12, as an addendum to the Woodbridge Building A TIR. In an effort to best address each basinwide (BW) and East Hylebos (EH) recommendation, applicable and short BW recommendations have been shown in their entirety in italics while the remaining BW recommendations have an abbreviated summary with page references to the Basin Plan. The associated compliance for each BW recommendation is shown in bold. We note that these are recommendations, not mandates, and that many of them use the permissive term “should” rather than the mandatory term “shall,” allowing the City flexibility to determine whether and how to apply the recommendations. 3.1 ZONING CONTROLS FOR STREAM CORRIDORS BW-1:Low Density Zoning Controls for Protection of Stream Corridors and Ravines This BW recommendation pertains to the areas within stream corridors that should be protected from development beyond a density limit and concerns the local jurisdictions. The full description for this recommendation is available starting on page 3-4 of the Basin Plan. The purpose of this BW recommendation is to provide low density zoning controls to protect stream corridors within specific regionally significant and locally significant resource areas (RSRAs and LSRAs). These resource areas are not identified on the proposed development property; therefore, this BW is not applicable for the project. 2 3.2 CONTROL OF VOLUME AND TIMING OF RUNOFF FROM DEVELOPING SITES BW-2:Basinwide Onsite Detention Standard To control downstream or downslope impacts of new development, including public and private street and highways, onsite retention/detention (RID) facilities in the Hylebos Creek and Lower Puget Sound basins should be designed to control the post-development 2- and 10-year flows to corresponding pre-development levels. The calculated storage volume should be increased by a safety factor or 30 percent to account for various uncertainties in the analysis and design. The design methodologies recommended are either a modification of the 1990 King County Design Manual or the use of a calibrated continuous hydrologic model. Following further modeling of these basins, it was determined that the existing Design Manual methodology would not enable development in the planning area to achieve the post- development run-off objectives of reducing peak 2-and 10-year flows to pre-developed levels. Therefore, one of the recommended methodologies includes modifications to the Design Manual methods. The modifications will produce a detention pond that reduces 2- and 10-year peak flows to pre-development rates. The modifications to the current manual include a 7-day design storm with a more representative distribution instead of a 24-hour storm and a more accurate method of determining the time of concentrations. For additional details regarding these modifications, contact King County SWM Basin Planning. The runoff mitigation standard discussed in this BW recommendation has been superseded since the 1998 King County Surface Water Design Manual (KCSWDM) and increased in the current 2016 KCSWDM. The project exceeds the BW-2 recommendation and is compliant and consistent with the more stringent BW-3 recommendation below. BW-3:Stream Protection Onsite Detention Standard In subcatchments where future flows are expected to have significant adverse impacts on stream stability and habitat, onsite detention ponds for new development, including public and private streets and highways, should be designed such that post-development flow peaks and durations are reduced to pre-development levels for flows greater than 50 percent of the 2-year and less than the 50-year. In addition, the 100-year post- development peak flow should be reduced to the 100-year pre-development level. The recommended method of designing these detention ponds is a calibrated continuous hydrologic model, preferably HSPF. An alternative to using a continuous hydrologic model is SCS methods with a design release rate such that the post-developed 100-year flow is released at 70-percent of the pre-development 2-year rate. A 24-hour design storm, as described in the 1990 King County Design Manual, is recommended. Additional design methods may become available in the future. Contact King County SWM Basin Planning for additional details. See Figures 4.1.3, 4.2.3, and 4.5.3 for areas where this standard applies. Affected Entities: 3 The Basinwide Onsite Detention Standard (BW-2) is a modification of the Design Manual. The design methodology of all entities currently using the Design Manual should be updated to include 7-day design storms and revised time of concentration calculations. The revised methodology produces detention ponds that are between 50 percent and 100 percent larger, depending on site density. Milton currently utilizes a less stringent standard that requires design of onsite detention ponds to control the 10-year storm. To be consistent with the Basin Plan, it is recommended that Milton adopt the detention standard in BW-2. The Stream Protection Onsite Detention Standard (BW-3) applies to parts of five entities in the basins: King County and Milton in subcatchment H2 on tributary 0015 on the East Branch Hylebos Creek and in Tacoma, Pierce County, and Federal Way in subcatchments J2, J6, J7, and J8 that drain into upper Joes Creek and subcatchment WH3 in tributary 0013 which flows into West Branch Hylebos Creek. Presently no affected entity has this standard in place. To be consistent with the Basin Plan it is recommended that Federal Way, King County, Milton, Pierce County, and Tacoma adopt recommendation BW-3 in the areas indicated. As described in the TIR, the project complies with the current Level 3 Flow Control Mitigation Standard, as defined in the 2016 KCSWDM which meets the intent of this BW recommendation, to reduce flow peaks and durations to pre-development levels for flows greater than 50 percent of the 2-year and less than the 50-year, up to the 100-year storm event. Therefore, the project is compliant and consistent with this BW recommendation. 3.3 SENSITIVE AREA PROTECTION BW-4:Stream Buffers This BW recommendation pertains to the required buffers for Class 2 & 3 streams, RSRAs, and LSRAs. The full description for this recommendation is available starting on page 3-9 of the Basin Plan. RSRAs or LSRAs (per Figure 2.1.1 of the Basin Plan) and Class 2 streams are not present on the project site. Stream EA was typed as a minor stream, as defined by the 1994 FWCC, which would be consistent with a Class 3 stream as defined within this Basin Study. The required 50-foot buffer for the onsite Stream EA is consistent with the 1994 FWCC and has been provided, as described in the Critical Areas Report and Buffer Averaging Plan by Talasaea Consultants, Inc., dated February 2020. This BW recommendation has been met for meeting the minimum Class 3 stream buffer. BW-5:Wetland Buffers At a minimum, the buffers should be 100 feet from the edge of Class 1 wetlands except for the west Hylebos Wetland RSRA and Spring Valley LSRA; 50 feet from Class 2, and 25 feet from Class 3 wetlands. The West Hylebos and Spring Valley Wetlands are the only wetlands that would not receive additional protection - from the shoreline management program; therefore these two wetlands should have a 150-foot buffer. 4 The Project only contains Class 2 and 3 wetlands, based on the definitions provided in the basin study. The wetland buffers used for the Project as required by the 1994 FWCC exceed the buffer requirements outlined in this recommendation. Standard wetland buffers have been provided with their approved modifications and are described in the Critical Areas Report and Buffer Averaging Plan by Talasaea Consultants, Inc., dated February 2020. BW-6:Livestock Access Control Access to streams and wetlands should be limited by fencing livestock from riparian buffers or other equivalent means. Provisions can be made for access to watering points. There are no livestock in or adjacent to the project site; therefore, this BW recommendation is not applicable. BW-7:Limitations on Stream Crossings and Stream Modification or Relocation This BW recommendation pertains to the limits of stream modification during stream crossing efforts with roads and utilities. The full description for this recommendation is available starting on page 3-10 of the Basin Plan. The project does not propose any stream crossings; therefore, this BW recommendation is not applicable. BW-8:Clearing, Grading, and Filling Limitations 1.Filling of more than three feet in vertical depth or excavation of more than five feet in vertical depth, or any grading that involves more than100 cubic yards of material, should require a permit. In environmentally sensitive areas such as streams, wetlands, steep slopes, or their buffers, a permit should be required for grading of any quantity or dimension. The project will acquire a permit for clearing and grading activities. 2.Erosion, sedimentation, and stormwater controls consistent with the 1990 King County Surface Water Design Manual or updates, as adopted by the entity, should be required to be in place and inspected for appropriate installation before clearing, grading, or filling begins. Regular inspection of these controls should be required at specific phases of site work to ensure these controls are functioning as designed. The project is implementing erosion and sedimentation controls consistent with the current 2016 KCSWDM and the DOE NPDES permit. 3.Sites that have been cleared, graded, or filled in violation of current or prior standards should be fully restored before construction permits are issued. Particular attention should be paid to sites that may be filled with unauthorized solid wastes. Any large releases of sediment or spills that are documented as non- compliance of permit conditions or cause water quality or habitat degradation should be fully compensated and restored before construction permits are issued. 5 The project has not been previously cleared, graded, or filled in violation of current or prior standards. 4.Significant trees should be identified during the platting process and retained on all sites. Significant trees are coniferous trees eight inches in diameter or greater, or any deciduous tree, other than red alder, 12 inches or more diameter, each measured 54 inches above grade. This project does not involve platting (subdivision) so this provision is not applicable. Nevertheless, a tree retention plan has been reviewed and approved by the City of Federal Way as part of the Process III application. The tree retention plan includes a managed forest buffer that will preserve existing significant trees. 5.Significant natural vegetation should be retained. Significant natural vegetation is a concentration of vegetation with significant biological importance such as dense, mature native vegetation that supports local wildlife. A tree retention plan has been reviewed and approved by the City of Federal Way as part of the Process III application that clearly documents the location of native trees to be retained across the Site. The tree retention plan includes areas of undisturbed natural vegetation that will be preserved and managed long-term. The areas of preserved natural vegetation will continue to support local wildlife, while the managed forest buffer will provide corridors for wildlife movement between this and other sites in the vicinity. In addition to the onsite retention of trees and natural vegetation, the campus broadly has designated areas that have been identified as Managed Forrest Buffer that contain significant natural vegetation that serve as wildlife habitat and wildlife corridors. 6.Areas with retained vegetation should be clearly and permanently marked on the site prior to starting site work, identified on all plat maps and title instruments, and have legally binding restrictions placed on them. The areas of retained vegetation and trees have been marked on the construction plans and will be clearly delineated in the field prior to the start of site work. The project has addressed all 6 items in this BW recommendation; therefore, the project is compliant and consistent with this BW recommendation. BW-9:Seasonal Clearing and Grading Limits Bare ground associated with clearing, grading, utility installation, building construction, and other development activity should be completely revegetated by October 1 and not disturbed until the following March 31. Earth-moving or land clearing activity should not occur during this period, except for regular maintenance for public facilities and public agency response to emergencies that threaten the public health, safety, and welfare. Landscaping of single-family residences, existing permitted commercial forestry and mining activities in areas zoned for resource use, and development sites with approved and constructed drainage facilities that infiltrate 100 percent of surface runoff should be 6 exempt from these restrictions, although appropriate measures as identified in BW-8.2 above, should be taken to prevent off-site movement of sediment. When land clearing is permitted, disturbed soil areas that are to be left unworked for more than 12 hours should be covered with appropriate erosion control measures as required in the 1990 King County Surface Water Design Manual to prevent off-site erosion. This recommendation is intended to reduce the “addition of fine-grained sediment to stream channels.” Basin Plan, page 3-8. In the nearly 20 years since the Basin Plan was developed, the KCSWDM has been updated to include best management practices (BMPs) to reduce sedimentation. The following BMPs are shown on the construction plans and will be included in the Stormwater Pollution Prevention Plan (SWPPP) associated with the DOE NPDES permit: ·Clearing Limits ·Orange Fabric Fence (serves as a silt fence and as a native growth protection fence) ·Storm Drain Inlet Protection ·Outlet Protection ·Interceptor Swales ·Stabilized Construction Entrances ·Temporary Sediment Ponds ·Dust Control ·Straw Wattles ·Temporary and Permanent Seeding ·Mulching ·Plastic Covering Additional BMPs may implemented as required by the DOE NPDES permit. These best management practice measures will ensure sediment does not enter Stream EA. In light of modern sediment control techniques, seasonal restrictions are not necessary. BW-10:Hillslope Development and Drainage Restrictions This BW recommendation pertains to the required buffers stormwater management for steep slopes and landslide hazard areas. The full description for this recommendation is available on page 3-15 of the Basin Plan. The project is not located on or near a steep slope; therefore, this BW recommendation is not applicable. BW-11:Wetland and Stream No Net Loss Policy A basinwide policy of no overall net loss of wetland and stream functions and values, and a net gain over time, should be adopted by all jurisdictions in the basins. This policy would be consistent with directives from the federal and state governments. The City has no jurisdiction over wetland and stream impacts for this Project, therefore this BW recommendation is not directly applicable to the Project. However, no net loss of wetland and stream functions and values is being met for the Project consistent with the current US Army Corps of Engineers (USACE) regulatory requirements. 7 BW-12:Order of Mitigation Impacts to streams, wetlands, or lakes should be mitigated using the following descending order of preference: 1.Avoid the impact all together by not taking a certain action or parts of an action; 2.Minimize impact by limiting the degree or magnitude of the action and its implementation by using appropriate technology, or by taking affirmative steps to avoid or reduce impact; 3.Rectify the impact by repairing, rehabilitating or restoring the affected sensitive areas; 4.Reduce or eliminate the impact over time by prevention and maintenance operations during the life of the actions; 5.Compensate for the impact by replacing, enhancing, or providing substitute sensitive areas and environments; 6.Monitor the impact and take appropriate corrective measures. This BW recommendation is consistent with the standard mitigation sequencing required by the USACE that was followed for both the City permitting effort as well as through the USACE permitting process to address the wetland impacts. The BW recommendation is met as described in the Critical Areas Report and Buffer Averaging Plan by Talasaea Consultants, Inc., dated February 2020. BW-13:Resource Replacement and Enhancement Standards 1.If a wetland must be altered or enhanced, the formulae for best wetland mitigation should be as follows with equal or greater biologic values: Class 1 and 2 wetlands on a 2:1 type and acreage basis Class 3 wetlands on a 1:1 type and acreage basis Projects whose primary objective is to restore the functions and values of a previously damaged wetland to approximate its pre-developed functions and values should be exempt from this mitigation requirement. This exemption should only apply, however, if the restoration is not mitigation for offsite or adjacent development impacts. 2.For all stream classes, mitigation plans should be developed to replace and enhance stream elements such as pools, riffles, LOD, and spawning gravel on a relative 2:1 basis in function and area. This mitigation may be accomplished at the project site or on another stream reach through mitigation banking. No stream impacts are proposed for this Project. The City has no jurisdiction over wetland impacts for this Project, therefore this BW recommendation is not directly applicable to the Project. However, wetland impacts are being addressed by current USACE regulatory requirements using the King County In- Lieu Fee (ILF) Program. The purchase of mitigation credits through the ILF Program has been recognized as being consistent with the wetland replacement ratios, consistent with those outlined above for this BW recommendation. Therefore, this BW recommendation is met with details provided in the Critical Areas Report and Buffer Averaging Plan by Talasaea Consultants, Inc., dated February 2020. 8 BW-14:Sensitive Area Mitigation Fund A fund should be established solely for use in enforcing and implementing sensitive areas codes. All moneys obtained from civil penalties and sensitive area violations should be deposited in this fund. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-15:Sensitive Area Mapping This BW recommendation pertains to the establishment of a sensitive area map within the study area of the basin plan. The full description for this recommendation is available starting on page 3-16 of the Basin Plan. This BW recommendation is applicable to the City of Federal Way and not applicable to the project. 3.4 BASIN REVEGETATION BW-16:Basin Revegetation This BW recommendation pertains to the revegetation of priority areas, the supporting infrastructure to carry out the revegetation, and to coordinate all actions through the Stream Steward (BW-38). The full description for this recommendation is available on page 3-26 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. 3.5 MANAGEMENT OF NONPOINT SOURCE WATER POLLUTION BW-17:BMP Programs for Control of Nonpoint Source Pollutants This BW recommendation pertains to the required mitigation efforts to minimize pollution from nonpoint source pollutants. The full description for this recommendation is available on pages 3-32 to 3-34 of the Basin Plan. As described in the TIR, due to the proposed use of the project site, source control is not required, and this BW recommendation is not applicable. The project will provide enhanced basic water quality treatment to reduce stormwater pollutants. BW-18:Highway Runoff Controls This BW recommendation pertains to the required flow rate mitigation for highways in the study area of the basin plan. The full description for this recommendation is available on page 3-34 of the Basin Plan. This BW recommendation is the responsibility of WSDOT and local entities; therefore, this BW recommendation not applicable. 9 BW-19:Collection and Disposal of Residuals This BW recommendation pertains to the collection and disposal of residuals collected in the private and public stormwater system. The full description for this recommendation is available starting on page 3-34 of the Basin Plan. This BW recommendation is the responsibility of the Public Works Department; therefore, this BW recommendation not applicable. BW-20:Maintenance of Roadside Ditches This BW recommendation pertains to the maintenance of roadside ditches with special instructions when within 1/4 mile of a Class 2 or 3 stream. The full description for this recommendation is available on page 3-35 of the basin plan. This BW recommendation is the responsibility of the Public Works Department; therefore, this BW recommendation not applicable. BW-21:Stormwater Infiltration Limitations Stormwater infiltration facilities should be used in rural and low- to moderate-density land- use areas wherever soil conditions are conducive to replenish groundwater and augment summer flows. New development should be required to determine the feasibility of infiltration and to provide such facilities to the extent possible. Infiltration facilities should not be used in high density areas with multifamily or commercial land uses (see also WHL- 4, Chapter 4.1). Infiltration was not considered feasible for this project by the geotechnical engineer; therefore, this BW recommendation is not applicable. BW-22:Lake Water Quality Management Programs This BW recommendation pertains to the suggested actions to be taken by lakeside residents. The full description for this recommendation is available starting on page 3-36 of the Basin Plan. This BW recommendation is the responsibility of lakeside residents; therefore, this BW recommendation not applicable. 3.6 PLAN MONITORING AND UPDATE BW-23:Database Management and Update This BW recommendation pertains to the basin-specific Database update and management procedures for the Stream Steward (BW-38). The full description for this recommendation is available on page 3-39 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-24:Flow and Development Monitoring 10 This BW recommendation pertains to the suggested flow and development monitoring to be carried out by the Stream Steward (BW-38). The full description for this recommendation is available starting on page 3-39 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-25:Sediment Transport Monitoring This BW recommendation pertains to the suggested sediment monitoring to be carried out by the Stream Steward (BW-38). The full description for this recommendation is available on page 3-40 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-26:Regional Monitoring This BW recommendation pertains to the suggested regional monitoring to be carried out by the Stream Steward (BW-38). The full description for this recommendation is available on page 3-40 of the basin plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-27:Sampling Methods This BW recommendation pertains to the suggested sampling methods to be used throughout the basin and to be enforced by the Stream Steward (BW-38). The full description for this recommendation is available on page 3-40 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-28:Short-Term Runoff Event Monitoring for Water Quality Constituents This BW recommendation pertains to sampling sites, to be used by the Stream Steward (BW-38). The full description for this recommendation is available on page 3-40 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-29:Short-Term Highway Runoff Monitoring WSDOT is developing a program to control the runoff from freeways and highways in the Puget Sound Basin (see BW-18). A sampling program should be developed that includes storm event monitoring of highways before and after BMP implementation. Variables to be monitored should include metals, solids, phosphorus, oil/grease, and hydrocarbons. 11 This BW recommendation is the responsibility of the Stream Steward (per BW-38) & WSDOT; therefore, this BW recommendation not applicable. BW-30:Short-Term Monitoring of Fecal Bacteria Source Areas This BW recommendation pertains to the suggested short-term monitoring of fecal bacteria source areas to be carried out by the Federal Way Water and Sewer District. The full description for this recommendation is available on page 3-43 of the basin plan. This BW recommendation is the responsibility of the Lakehaven Water and Sewer District; therefore, this BW recommendation not applicable. BW-31:Long-Term Monitoring for Water Quality Trends This BW recommendation pertains to the suggested long-term monitoring of water quality to be carried out by the Stream Steward (BW-38). The full description for this recommendation is available on page 3-43 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-32:Annual Report and Plan Amendment This BW recommendation pertains to the suggested additional resources that should be made available to the Stream Steward (BW-38) by the citizens to carry out the basin plan. The full description for this recommendation is available starting on page 3-43 of the Basin Plan. The project owner is not part of the citizens’ committee; therefore, this BW recommendation is not applicable. 3.7 CODE COMPLIANCE BW-33:Enforcement/Inspection Staff This BW recommendation pertains to the suggested additional enforcement staff that should be made available to enforce the basin plan. The full description for this recommendation is available on page 3-45 of the Basin Plan. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. BW-34:Citations A system for issuing citations with civil penalties, analogous to traffic tickets but with greater penalties, should be established for violations of drainage and environmentally sensitive areas ordinances. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. 12 BW-35:Penalties This BW recommendation pertains to the suggested penalties for violations of code. The full description for this recommendation is available on page 3-46 of the Basin Plan. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. BW-36:Violation Reporting This BW recommendation pertains to the suggested violation reporting improvements. The full description for this recommendation is available on page 3-46 of the Basin Plan. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. 3.8 EDUCATION AND PUBLIC INVOLVEMENT BW-37:Education and Public Involvement This BW recommendation pertains to the suggested education and public involvement to be carried out by the Stream Steward (BW-38). The full description for this recommendation is available on page 3-47 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. 3.9 STREAM STEWARD BW-38:Stream Steward This BW recommendation pertains to employing a Stream Steward. The full description for this recommendation is available on page 3-49 of the Basin Plan. The Stream Steward employment is not the responsibility of the project; therefore, this BW recommendation is not applicable. 3.10 TAX INCENTIVES BW-39:Current-Use Taxation Current use taxation programs should be expanded to include properties that contain stream and wetland buffers within RSRAs and LSRAs as identified in this Basin Plan. A rating system should be adopted by all jurisdictions in the basins to evaluate the public benefit of accepting these areas into the open space system in exchange for private tax concessions. This BW recommendation is the responsibility of the local jurisdictions and the Assessor; therefore, this BW recommendation not applicable. 13 BW-40:State Assessment Procedures The statutes governing appeals of property-tax assessments should be amended to allow simplified appeals where downzones or sensitive areas designations have affected potential development opportunities. The appeal results should apply without need for further property-owner action until the next regular valuation becomes effective. This BW recommendation is the responsibility of the local jurisdictions and the Assessor; therefore, this BW recommendation not applicable. BW-41:Conservation Easements and Land Trusts Encourage private donations of conservation easements for streams, wetlands, and their buffers in RSRAs, LSRAs, and wildlife corridors to public and private caretaker agencies. Public caretaker agencies include the King County Parks Division and private conservation groups include the Trust for Public Lands. Similar programs can also be established in Des Moines, Federal Way, Kent, Milton, and Tacoma. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. 3.11 PROGRAM MANAGEMENT BW-42:Annexations and Incorporations If annexations or incorporations remove areas of the basins from King County's jurisdiction, interlocal agreements should be drafted to ensure that city surface water management plans are consistent with, or more protective than, this Basin Plan. King County and other cooperators on this Basin Plan should oppose those proposed annexations that do not meet this standard. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. BW-43:King County SWM Division CIP Funding Policy Implementation of the Basin Plan in King County will follow the recommended policy identified in the SWM Strategic Plan. All capital improvements projects in King County will be funded at a level to at least begin initial design work during the calendar year following Basin Plan adoption. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. EH-1:Supplemental Onsite Detention Supplemental onsite detention should be applied in subcatchment H2 in the East Branch Hylebos sub-basin according to BW-3 in order to effectively reduce future peak flows. This supplemental standard should be applied until the recommended SR 161 Regional Detention Pond (Project 2446) is constructed. Upon completion of the regional pond, 14 onsite detention should be designed according to the basinwide recommendation (BW-2) pending appropriate flow controls as shown by flow monitoring data. This BW recommendation is not applicable to the project site. EH-2:Stream Corridor Protection A stream buffer to protect this RSRA is required along the tributary 0006 ravine (an RSRA) within subcatchment H1 (see BW-4). The buffer width should be at least 150 feet from the ordinary high water on each side of the stream or 50 feet beyond the top of hillslope on each side of the ravine, whichever is further from the ravine. Maintenance of intact vegetated corridors dominated by conifer trees along the stream are necessary to maintain stream stability and sustain fisheries in this resources area. This BW recommendation is not applicable to the project site. EH-3:Low Density Stream Protection Zoning The East Branch Hylebos ravine, an RSRA, should be zoned rural at 1 unit per 5 acres to protect the significant resource (see BW-1). This low-density area encompasses the ravine (RM 6.0 to 6.75) and include the King County inventoried wetland, Hylebos Wetland 37. This BW recommendation is the responsibility of the local jurisdictions and it is not on the project site; therefore, this BW recommendation not applicable. EH-4:East Branch Hylebos Ravine Biomonitoring A biomonitoring program to supplement regular water quality monitoring should be established to provide continuous assessment of biological effects of water quality conditions entering the East Hylebos ravine. Fish held in streamside aquaria would be subject to stream water and monitored regularly to indicate incidents of acute toxicity from the stream. This BW recommendation is the responsibility of the local jurisdictions and it is not on the project site; therefore, this BW recommendation not applicable. If you have any questions regarding the information presented in this adjustment request, please feel free to contact me at (253) 838-6113 or laura@esmcivil.com. \\esm8\engr\esm-jobs\1886\001\016-0015\document\memo-015.docx Appendix F WWHM2012 PROJECT REPORT Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 2 General Model Information Project Name:Woodbridge Bldg A & B Site Name:Woodbridge Building A - Detention & WQ Site Address: City:Federal Way Report Date:8/5/2020 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:Hourly Precip Scale:0.000 (adjusted) Version Date:2019/09/13 Version:4.2.17 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year Low Flow Threshold for POC3:50 Percent of the 2 Year High Flow Threshold for POC3:50 Year Low Flow Threshold for POC4:50 Percent of the 2 Year High Flow Threshold for POC4:50 Year Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 3 Landuse Basin Data Predeveloped Land Use PreDev - Building A - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 12.07 Pervious Total 12.07 Impervious Land Use acre Impervious Total 0 Basin Total 12.07 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 4 PreDev - Building A - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.14 Pervious Total 0.14 Impervious Land Use acre Impervious Total 0 Basin Total 0.14 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 5 PreDev - Building A ROW - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.02 Pervious Total 0.02 Impervious Land Use acre Impervious Total 0 Basin Total 0.02 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 6 PreDev - Building A ROW - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.28 Pervious Total 0.28 Impervious Land Use acre Impervious Total 0 Basin Total 0.28 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 7 PreDev - Building B Parcel Improvments - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 12.67 Pervious Total 12.67 Impervious Land Use acre Impervious Total 0 Basin Total 12.67 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 8 PreDev - Building A - Oil/Water Sep Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.05 Pervious Total 0.05 Impervious Land Use acre ROADS FLAT 2.36 Impervious Total 2.36 Basin Total 2.41 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 9 PreDev - Building A ROW - Un-Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.48 Pervious Total 0.48 Impervious Land Use acre Impervious Total 0 Basin Total 0.48 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 10 PreDev - Building B - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.03 Pervious Total 0.03 Impervious Land Use acre Impervious Total 0 Basin Total 0.03 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 11 POC 4 - Node Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 1 Pervious Total 1 Impervious Land Use acre Impervious Total 0 Basin Total 1 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 12 Existing - Offsite Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 100 Pervious Total 100 Impervious Land Use acre ROADS FLAT 100 Impervious Total 100 Basin Total 200 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 13 Mitigated Land Use Dev - Building B Parcel Improvments - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 3.39 Pervious Total 3.39 Impervious Land Use acre ROADS FLAT 4.37 ROOF TOPS FLAT 4.91 Impervious Total 9.28 Basin Total 12.67 Element Flows To: Surface Interflow Groundwater Detention Pond - 2:1 Side SlopesDetention Pond - 2:1 Side SlopesDetention Pond - 2:1 Side Slopes Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 14 Dev - Building A - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.2 C, Forest, Flat 0.92 Pervious Total 2.12 Impervious Land Use acre ROADS FLAT 4.76 ROOF TOPS FLAT 5.19 Impervious Total 9.95 Basin Total 12.07 Element Flows To: Surface Interflow Groundwater Detention Pond - 2:1 Side SlopesDetention Pond - 2:1 Side SlopesDetention Pond - 2:1 Side Slopes Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 15 Dev - Building A ROW - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.01 Pervious Total 0.01 Impervious Land Use acre ROADS FLAT 0.04 Impervious Total 0.04 Basin Total 0.05 Element Flows To: Surface Interflow Groundwater Detention Pond - 2:1 Side SlopesDetention Pond - 2:1 Side SlopesDetention Pond - 2:1 Side Slopes Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 16 Dev - Building A ROW - Bypass Bypass:Yes GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.28 Impervious Total 0.28 Basin Total 0.28 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 17 Dev - Building A - Bypass Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.07 Pervious Total 0.07 Impervious Land Use acre ROADS FLAT 0.07 Impervious Total 0.07 Basin Total 0.14 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 18 Dev - Building A - Oil/Water Sep Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.05 Pervious Total 0.05 Impervious Land Use acre ROADS FLAT 2.36 Impervious Total 2.36 Basin Total 2.41 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 19 PreDev - Building A ROW - Un-Detained Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre SIDEWALKS FLAT 0.48 Impervious Total 0.48 Basin Total 0.48 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 20 Dev - Building B - Bypass Bypass:Yes GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.03 Impervious Total 0.03 Basin Total 0.03 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 21 Existing - Offsite Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 100 Pervious Total 100 Impervious Land Use acre ROADS FLAT 100 Impervious Total 100 Basin Total 200 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 23 Mitigated Routing Detention Pond - 2:1 Side Slopes Bottom Length:190.00 ft. Bottom Width:265.00 ft. Depth:9 ft. Volume at riser head:10.0451 acre-feet. Side slope 1:2 To 1 Side slope 2:2 To 1 Side slope 3:2 To 1 Side slope 4:2 To 1 Discharge Structure Riser Height:7.5 ft. Riser Diameter:24 in. Notch Type:Rectangular Notch Width:0.021 ft. Notch Height:1.750 ft. Orifice 1 Diameter:2.375 in.Elevation:0 ft. Orifice 2 Diameter:2.75 in.Elevation:4.25 ft. Orifice 3 Diameter:2.75 in.Elevation:5.25 ft. Element Flows To: Outlet 1 Outlet 2 POC 1 Analysis Node Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 374.50 1.155 0.000 0.000 0.000 374.60 1.160 0.115 0.048 0.000 374.70 1.164 0.232 0.068 0.000 374.80 1.168 0.348 0.083 0.000 374.90 1.172 0.465 0.096 0.000 375.00 1.176 0.583 0.108 0.000 375.10 1.181 0.701 0.118 0.000 375.20 1.185 0.819 0.128 0.000 375.30 1.189 0.938 0.136 0.000 375.40 1.193 1.057 0.145 0.000 375.50 1.198 1.176 0.153 0.000 375.60 1.202 1.296 0.160 0.000 375.70 1.206 1.417 0.167 0.000 375.80 1.210 1.538 0.174 0.000 375.90 1.215 1.659 0.181 0.000 376.00 1.219 1.781 0.187 0.000 376.10 1.223 1.903 0.193 0.000 376.20 1.228 2.026 0.199 0.000 376.30 1.232 2.149 0.205 0.000 376.40 1.236 2.272 0.211 0.000 376.50 1.240 2.396 0.216 0.000 376.60 1.245 2.520 0.221 0.000 376.70 1.249 2.645 0.227 0.000 376.80 1.253 2.770 0.232 0.000 376.90 1.258 2.896 0.237 0.000 377.00 1.262 3.022 0.242 0.000 377.10 1.267 3.148 0.246 0.000 377.20 1.271 3.275 0.251 0.000 377.30 1.275 3.402 0.256 0.000 377.40 1.280 3.530 0.260 0.000 Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 24 377.50 1.284 3.659 0.265 0.000 377.60 1.288 3.787 0.269 0.000 377.70 1.293 3.916 0.273 0.000 377.80 1.297 4.046 0.278 0.000 377.90 1.302 4.176 0.282 0.000 378.00 1.306 4.306 0.286 0.000 378.10 1.311 4.437 0.290 0.000 378.20 1.315 4.568 0.294 0.000 378.30 1.320 4.700 0.298 0.000 378.40 1.324 4.832 0.302 0.000 378.50 1.328 4.965 0.306 0.000 378.60 1.333 5.098 0.309 0.000 378.70 1.337 5.232 0.313 0.000 378.80 1.342 5.366 0.363 0.000 378.90 1.346 5.500 0.400 0.000 379.00 1.351 5.635 0.427 0.000 379.10 1.355 5.771 0.449 0.000 379.20 1.360 5.906 0.469 0.000 379.30 1.364 6.043 0.487 0.000 379.40 1.369 6.179 0.504 0.000 379.50 1.374 6.317 0.520 0.000 379.60 1.378 6.454 0.534 0.000 379.70 1.383 6.592 0.549 0.000 379.80 1.387 6.731 0.608 0.000 379.90 1.392 6.870 0.655 0.000 380.00 1.396 7.009 0.691 0.000 380.10 1.401 7.149 0.722 0.000 380.20 1.406 7.289 0.750 0.000 380.30 1.410 7.430 0.777 0.000 380.40 1.415 7.572 0.804 0.000 380.50 1.419 7.713 0.832 0.000 380.60 1.424 7.856 0.859 0.000 380.70 1.429 7.998 0.886 0.000 380.80 1.433 8.141 0.913 0.000 380.90 1.438 8.285 0.939 0.000 381.00 1.443 8.429 0.965 0.000 381.10 1.447 8.574 0.991 0.000 381.20 1.452 8.719 1.016 0.000 381.30 1.457 8.864 1.042 0.000 381.40 1.461 9.010 1.068 0.000 381.50 1.466 9.156 1.094 0.000 381.60 1.471 9.303 1.120 0.000 381.70 1.475 9.451 1.177 0.000 381.80 1.480 9.598 1.207 0.000 381.90 1.485 9.747 1.236 0.000 382.00 1.489 9.895 1.266 0.000 382.10 1.494 10.04 1.952 0.000 382.20 1.499 10.19 3.183 0.000 382.30 1.504 10.34 4.732 0.000 382.40 1.508 10.49 6.460 0.000 382.50 1.513 10.64 8.227 0.000 382.60 1.518 10.79 9.894 0.000 382.70 1.523 10.95 11.33 0.000 382.80 1.528 11.10 12.47 0.000 382.90 1.532 11.25 13.28 0.000 383.00 1.537 11.41 13.87 0.000 383.10 1.542 11.56 14.63 0.000 383.20 1.547 11.71 15.23 0.000 Woodbridge Bldg A & B 8/5/2020 3:15:17 PM Page 25 383.30 1.552 11.87 15.81 0.000 383.40 1.556 12.02 16.36 0.000 383.50 1.561 12.18 16.90 0.000 383.60 1.566 12.34 17.42 0.000 Woodbridge Bldg A & B 8/5/2020 3:15:27 PM Page 35 Wetland Input Volumes - Percent - Predeveloped - Mitigated Wetlands Input Volume for POC 1 Average Annual Volume (acft) Series 1: 501 POC 1 Predeveloped flow Series 2: 801 POC 1 Mitigated flow Month Series 1 Series 2 Percent Pass/Fail Jan 85.9416 88.6643 103.2 Pass Feb 60.7001 62.1494 102.4 Pass Mar 50.8893 51.8541 101.9 Pass Apr 31.0986 31.2663 100.5 Pass May 17.5554 17.4262 99.3 Pass Jun 14.5546 14.7488 101.3 Pass Jul 8.7295 8.3660 95.8 Pass Aug 10.9018 11.0680 101.5 Pass Sep 14.5384 15.6249 107.5 Pass Oct 33.0775 36.6148 110.7 Pass Nov 75.0489 81.6231 108.8 Pass Dec 84.0934 89.2002 106.1 Pass Day Predevel Mitigated Percent Pass/Fail Jan1 3.3511 3.4621 103.3 Pass 2 2.5118 2.6185 104.2 Pass 3 2.7325 2.8502 104.3 Pass 4 3.2172 3.3110 102.9 Pass 5 2.9302 3.0160 102.9 Pass 6 3.3648 3.4452 102.4 Pass 7 2.7023 2.8012 103.7 Pass 8 2.8726 2.9755 103.6 Pass 9 2.4352 2.5632 105.3 Pass 10 2.2579 2.3889 105.8 Pass 11 2.4933 2.6011 104.3 Pass 12 2.8998 2.9999 103.5 Pass 13 3.4459 3.5188 102.1 Pass 14 2.9558 3.0131 101.9 Pass Woodbridge Bldg A & B 8/5/2020 3:15:28 PM Page 36 15 2.7122 2.7863 102.7 Pass 16 2.7785 2.8548 102.7 Pass 17 2.8949 2.9699 102.6 Pass 18 3.0343 3.0884 101.8 Pass 19 2.8392 2.8946 102.0 Pass 20 2.5990 2.6762 103.0 Pass 21 2.4744 2.5694 103.8 Pass 22 3.0989 3.1951 103.1 Pass 23 3.1685 3.2462 102.4 Pass 24 2.4838 2.5677 103.4 Pass 25 2.2790 2.3734 104.1 Pass 26 2.3172 2.4020 103.7 Pass 27 2.3264 2.4041 103.3 Pass 28 2.7006 2.7706 102.6 Pass 29 2.7412 2.7908 101.8 Pass 30 2.8908 2.9547 102.2 Pass 31 2.4443 2.5122 102.8 Pass Feb1 2.2648 2.3423 103.4 Pass 2 1.9241 2.0082 104.4 Pass 3 1.9621 2.0383 103.9 Pass 4 1.6453 1.7287 105.1 Pass 5 2.1454 2.2133 103.2 Pass 6 2.1478 2.2034 102.6 Pass 7 2.7863 2.8151 101.0 Pass 8 2.3508 2.3917 101.7 Pass 9 1.9643 2.0375 103.7 Pass 10 1.7876 1.8713 104.7 Pass 11 2.3197 2.3906 103.1 Pass 12 2.0816 2.1377 102.7 Pass 13 1.9194 1.9780 103.1 Pass 14 2.2512 2.3036 102.3 Pass 15 2.5559 2.6017 101.8 Pass 16 2.3406 2.3814 101.7 Pass 17 2.4752 2.5221 101.9 Pass 18 2.8116 2.8269 100.5 Pass 19 2.0497 2.0735 101.2 Pass 20 2.0647 2.1010 101.8 Pass 21 1.8755 1.9163 102.2 Pass 22 1.9332 1.9755 102.2 Pass 23 2.1659 2.1971 101.4 Pass 24 2.0357 2.0716 101.8 Pass 25 1.7862 1.8302 102.5 Pass 26 2.0375 2.0676 101.5 Pass 27 2.0688 2.1062 101.8 Pass 28 1.9240 1.9313 100.4 Pass 29 1.8155 1.8758 103.3 Pass Mar1 1.7538 1.8078 103.1 Pass 2 2.2909 2.3270 101.6 Pass 3 1.9382 1.9673 101.5 Pass 4 2.1983 2.2270 101.3 Pass 5 1.4472 1.4864 102.7 Pass 6 1.4847 1.5221 102.5 Pass 7 1.7258 1.7683 102.5 Pass 8 2.0298 2.0603 101.5 Pass 9 1.8968 1.9230 101.4 Pass 10 2.0093 2.0379 101.4 Pass 11 2.2458 2.2666 100.9 Pass 12 1.6663 1.6925 101.6 Pass Woodbridge Bldg A & B 8/5/2020 3:15:28 PM Page 37 13 1.6739 1.7048 101.8 Pass 14 1.8133 1.8425 101.6 Pass 15 1.5876 1.6224 102.2 Pass 16 1.5458 1.5723 101.7 Pass 17 1.7199 1.7495 101.7 Pass 18 1.3858 1.4125 101.9 Pass 19 1.3042 1.3371 102.5 Pass 20 1.0823 1.1155 103.1 Pass 21 1.7031 1.7253 101.3 Pass 22 1.7824 1.7997 101.0 Pass 23 1.6524 1.6779 101.5 Pass 24 1.3872 1.4165 102.1 Pass 25 1.3466 1.3807 102.5 Pass 26 1.2953 1.3249 102.3 Pass 27 1.2590 1.2861 102.2 Pass 28 1.4015 1.4300 102.0 Pass 29 1.3145 1.3387 101.8 Pass 30 1.1328 1.1558 102.0 Pass 31 1.1696 1.1927 102.0 Pass Apr1 1.1108 1.1366 102.3 Pass 2 1.1629 1.1801 101.5 Pass 3 1.5491 1.5459 99.8 Pass 4 1.3937 1.3815 99.1 Pass 5 1.2439 1.2367 99.4 Pass 6 0.9418 0.9392 99.7 Pass 7 1.2054 1.2039 99.9 Pass 8 1.3202 1.3170 99.8 Pass 9 0.9901 0.9897 100.0 Pass 10 1.0966 1.1091 101.1 Pass 11 1.0494 1.0650 101.5 Pass 12 1.2341 1.2536 101.6 Pass 13 1.0286 1.0529 102.4 Pass 14 0.9450 0.9704 102.7 Pass 15 1.2540 1.2685 101.2 Pass 16 1.0761 1.0807 100.4 Pass 17 0.7208 0.7277 101.0 Pass 18 1.4806 1.4877 100.5 Pass 19 0.9337 0.9304 99.6 Pass 20 0.6926 0.6969 100.6 Pass 21 0.9439 0.9437 100.0 Pass 22 1.1280 1.1162 99.0 Pass 23 0.8345 0.8339 99.9 Pass 24 0.6898 0.6899 100.0 Pass 25 0.5757 0.5720 99.4 Pass 26 0.9019 0.9042 100.2 Pass 27 0.6584 0.6652 101.0 Pass 28 0.8817 0.8854 100.4 Pass 29 0.8860 0.8899 100.4 Pass 30 0.8336 0.8353 100.2 Pass May1 0.6692 0.6760 101.0 Pass 2 0.5711 0.5792 101.4 Pass 3 0.6410 0.6398 99.8 Pass 4 0.6622 0.6598 99.6 Pass 5 0.6960 0.6909 99.3 Pass 6 0.5520 0.5433 98.4 Pass 7 0.4860 0.4800 98.8 Pass 8 0.4883 0.4780 97.9 Pass 9 0.5152 0.5011 97.3 Pass Woodbridge Bldg A & B 8/5/2020 3:15:28 PM Page 38 10 0.6437 0.6392 99.3 Pass 11 0.4604 0.4521 98.2 Pass 12 0.5014 0.4893 97.6 Pass 13 0.6325 0.6220 98.3 Pass 14 0.5427 0.5326 98.2 Pass 15 0.4976 0.4898 98.4 Pass 16 0.4738 0.4649 98.1 Pass 17 0.5376 0.5310 98.8 Pass 18 0.6293 0.6256 99.4 Pass 19 0.4761 0.4762 100.0 Pass 20 0.4172 0.4124 98.8 Pass 21 0.4034 0.3908 96.9 Pass 22 0.5129 0.4998 97.4 Pass 23 0.5230 0.5162 98.7 Pass 24 0.3847 0.3783 98.3 Pass 25 0.6193 0.6162 99.5 Pass 26 0.5325 0.5350 100.5 Pass 27 0.5248 0.5249 100.0 Pass 28 0.7148 0.7159 100.2 Pass 29 0.7060 0.7113 100.7 Pass 30 0.7072 0.7195 101.7 Pass 31 0.6405 0.6517 101.8 Pass Jun1 0.5382 0.5482 101.8 Pass 2 0.6819 0.6922 101.5 Pass 3 0.6835 0.7023 102.8 Pass 4 0.4564 0.4746 104.0 Pass 5 0.6599 0.6782 102.8 Pass 6 0.6547 0.6758 103.2 Pass 7 0.5666 0.5817 102.7 Pass 8 0.6021 0.6166 102.4 Pass 9 0.5974 0.6138 102.7 Pass 10 0.5946 0.6120 102.9 Pass 11 0.5352 0.5565 104.0 Pass 12 0.3340 0.3497 104.7 Pass 13 0.3061 0.3118 101.9 Pass 14 0.3737 0.3721 99.6 Pass 15 0.3981 0.3944 99.1 Pass 16 0.5346 0.5342 99.9 Pass 17 0.3286 0.3265 99.4 Pass 18 0.3277 0.3196 97.5 Pass 19 0.4385 0.4292 97.9 Pass 20 0.4572 0.4469 97.8 Pass 21 0.3662 0.3531 96.4 Pass 22 0.3912 0.3807 97.3 Pass 23 0.8528 0.8572 100.5 Pass 24 0.4040 0.4163 103.0 Pass 25 0.3324 0.3405 102.4 Pass 26 0.3325 0.3366 101.2 Pass 27 0.3962 0.3992 100.8 Pass 28 0.3712 0.3765 101.4 Pass 29 0.3984 0.4005 100.5 Pass 30 0.4339 0.4345 100.1 Pass Jul1 0.3432 0.3410 99.4 Pass 2 0.3270 0.3234 98.9 Pass 3 0.2769 0.2688 97.1 Pass 4 0.3491 0.3393 97.2 Pass 5 0.2546 0.2451 96.2 Pass 6 0.3215 0.3084 95.9 Pass Woodbridge Bldg A & B 8/5/2020 3:15:28 PM Page 39 7 0.3537 0.3456 97.7 Pass 8 0.3987 0.3934 98.7 Pass 9 0.3085 0.3027 98.1 Pass 10 0.2287 0.2211 96.7 Pass 11 0.3950 0.3881 98.3 Pass 12 0.3404 0.3306 97.1 Pass 13 0.3271 0.3147 96.2 Pass 14 0.1965 0.1832 93.2 Pass 15 0.4868 0.4810 98.8 Pass 16 0.2568 0.2534 98.7 Pass 17 0.2107 0.2021 95.9 Pass 18 0.2645 0.2550 96.4 Pass 19 0.2353 0.2228 94.7 Pass 20 0.2054 0.1872 91.2 Pass 21 0.2582 0.2397 92.8 Pass 22 0.2207 0.2019 91.5 Pass 23 0.1924 0.1713 89.1 Pass 24 0.2051 0.1828 89.1 Pass 25 0.3828 0.3672 95.9 Pass 26 0.2153 0.2003 93.0 Pass 27 0.2053 0.1908 92.9 Pass 28 0.1704 0.1519 89.2 Pass 29 0.1839 0.1617 87.9 Pass 30 0.1812 0.1569 86.6 Pass 31 0.2526 0.2319 91.8 Pass Aug1 0.2929 0.2765 94.4 Pass 2 0.3365 0.3265 97.0 Pass 3 0.2458 0.2340 95.2 Pass 4 0.1795 0.1649 91.9 Pass 5 0.3479 0.3355 96.4 Pass 6 0.3767 0.3711 98.5 Pass 7 0.1820 0.1770 97.3 Pass 8 0.3292 0.3272 99.4 Pass 9 0.1896 0.1860 98.1 Pass 10 0.2263 0.2198 97.1 Pass 11 0.2198 0.2115 96.2 Pass 12 0.1911 0.1799 94.2 Pass 13 0.4221 0.4133 97.9 Pass 14 0.4790 0.4769 99.6 Pass 15 0.2584 0.2587 100.1 Pass 16 0.3142 0.3156 100.5 Pass 17 0.4535 0.4582 101.0 Pass 18 0.4104 0.4199 102.3 Pass 19 0.2703 0.2821 104.4 Pass 20 0.3826 0.3935 102.9 Pass 21 0.4953 0.5172 104.4 Pass 22 0.7062 0.7318 103.6 Pass 23 0.5110 0.5412 105.9 Pass 24 0.4170 0.4458 106.9 Pass 25 0.4850 0.5140 106.0 Pass 26 0.4611 0.4892 106.1 Pass 27 0.3674 0.3942 107.3 Pass 28 0.4490 0.4764 106.1 Pass 29 0.3198 0.3449 107.8 Pass 30 0.3298 0.3531 107.1 Pass 31 0.3932 0.4156 105.7 Pass Sep1 0.4259 0.4509 105.9 Pass 2 0.3239 0.3472 107.2 Pass Woodbridge Bldg A & B 8/5/2020 3:15:28 PM Page 40 3 0.4645 0.4936 106.2 Pass 4 0.2847 0.3103 109.0 Pass 5 0.4360 0.4633 106.3 Pass 6 0.1975 0.2199 111.3 Pass 7 0.4155 0.4368 105.1 Pass 8 0.3133 0.3347 106.8 Pass 9 0.5029 0.5250 104.4 Pass 10 0.3645 0.3934 107.9 Pass 11 0.2483 0.2687 108.2 Pass 12 0.2909 0.3034 104.3 Pass 13 0.5189 0.5389 103.8 Pass 14 0.3551 0.3768 106.1 Pass 15 0.4074 0.4286 105.2 Pass 16 0.9813 1.0218 104.1 Pass 17 0.4925 0.5413 109.9 Pass 18 0.5886 0.6415 109.0 Pass 19 0.5299 0.5801 109.5 Pass 20 0.4669 0.5151 110.3 Pass 21 0.8744 0.9192 105.1 Pass 22 0.6618 0.7094 107.2 Pass 23 0.5799 0.6276 108.2 Pass 24 0.5190 0.5703 109.9 Pass 25 0.5443 0.5996 110.2 Pass 26 0.5479 0.6029 110.1 Pass 27 0.6116 0.6755 110.4 Pass 28 0.4365 0.4926 112.9 Pass 29 0.7613 0.8210 107.8 Pass 30 0.5009 0.5567 111.1 Pass Oct1 0.5137 0.5672 110.4 Pass 2 0.6659 0.7236 108.7 Pass 3 0.8800 0.9517 108.2 Pass 4 0.6841 0.7574 110.7 Pass 5 1.2865 1.3625 105.9 Pass 6 0.7275 0.8084 111.1 Pass 7 1.3352 1.4290 107.0 Pass 8 1.2927 1.3979 108.1 Pass 9 1.1670 1.2758 109.3 Pass 10 0.6310 0.7397 117.2 Pass 11 0.6555 0.7602 116.0 Pass 12 0.6967 0.8068 115.8 Pass 13 0.7171 0.8211 114.5 Pass 14 0.6490 0.7554 116.4 Pass 15 0.7129 0.8159 114.4 Pass 16 1.0698 1.1726 109.6 Pass 17 0.9626 1.0669 110.8 Pass 18 1.2695 1.3812 108.8 Pass 19 2.1467 2.2740 105.9 Pass 20 1.5047 1.6480 109.5 Pass 21 1.2798 1.4252 111.4 Pass 22 1.0679 1.2147 113.7 Pass 23 1.1069 1.2557 113.4 Pass 24 1.1657 1.3133 112.7 Pass 25 1.3746 1.5251 110.9 Pass 26 1.5891 1.7405 109.5 Pass 27 1.4426 1.6048 111.2 Pass 28 1.3496 1.5119 112.0 Pass 29 1.1002 1.2538 114.0 Pass 30 1.5321 1.6979 110.8 Pass Woodbridge Bldg A & B 8/5/2020 3:15:28 PM Page 41 31 1.3859 1.5578 112.4 Pass Nov1 1.7251 1.9025 110.3 Pass 2 2.3014 2.4886 108.1 Pass 3 2.3746 2.5835 108.8 Pass 4 1.5982 1.8104 113.3 Pass 5 2.2887 2.5017 109.3 Pass 6 1.9135 2.1308 111.4 Pass 7 1.7177 1.9291 112.3 Pass 8 2.3225 2.5382 109.3 Pass 9 2.4334 2.6544 109.1 Pass 10 2.9754 3.1996 107.5 Pass 11 2.7933 3.0285 108.4 Pass 12 2.7631 3.0116 109.0 Pass 13 2.4445 2.6859 109.9 Pass 14 1.9839 2.2225 112.0 Pass 15 2.3830 2.6320 110.5 Pass 16 2.3642 2.6152 110.6 Pass 17 2.2071 2.4453 110.8 Pass 18 3.2448 3.4749 107.1 Pass 19 3.2288 3.4504 106.9 Pass 20 2.5390 2.7607 108.7 Pass 21 2.3392 2.5640 109.6 Pass 22 3.2029 3.4250 106.9 Pass 23 3.7223 3.9203 105.3 Pass 24 3.7319 3.9328 105.4 Pass 25 2.8828 3.1000 107.5 Pass 26 2.5466 2.7725 108.9 Pass 27 2.2199 2.4467 110.2 Pass 28 2.4592 2.6747 108.8 Pass 29 2.9560 3.1636 107.0 Pass 30 2.7254 2.9467 108.1 Pass Dec1 2.8841 3.1100 107.8 Pass 2 3.6890 3.8706 104.9 Pass 3 2.4982 2.6844 107.5 Pass 4 2.8466 3.0524 107.2 Pass 5 2.5074 2.7075 108.0 Pass 6 2.2042 2.4034 109.0 Pass 7 2.3052 2.5020 108.5 Pass 8 2.6169 2.8052 107.2 Pass 9 2.9788 3.1587 106.0 Pass 10 2.8616 3.0342 106.0 Pass 11 2.9560 3.1271 105.8 Pass 12 2.9840 3.1568 105.8 Pass 13 3.0369 3.2051 105.5 Pass 14 3.5005 3.6365 103.9 Pass 15 2.8687 3.0284 105.6 Pass 16 2.4155 2.5940 107.4 Pass 17 2.2950 2.4782 108.0 Pass 18 2.3049 2.4878 107.9 Pass 19 2.9255 3.0813 105.3 Pass 20 2.7225 2.8848 106.0 Pass 21 2.4208 2.5920 107.1 Pass 22 2.5312 2.6905 106.3 Pass 23 2.2530 2.4075 106.9 Pass 24 2.3962 2.5427 106.1 Pass 25 3.0323 3.1520 103.9 Pass 26 3.0556 3.1497 103.1 Pass 27 2.0749 2.1894 105.5 Pass Woodbridge Bldg A & B 8/5/2020 3:15:28 PM Page 42 28 2.8781 2.9990 104.2 Pass 29 3.1067 3.1909 102.7 Pass 30 2.2183 2.3313 105.1 Pass 31 2.4325 2.5550 105.0 Pass Woodbridge Bldg A & B 8/5/2020 3:16:20 PM Page 69 Appendix Predeveloped Schematic Woodbridge Bldg A & B 8/5/2020 3:16:21 PM Page 70 Mitigated Schematic Woodbridge Bldg A & B 8/5/2020 3:16:21 PM Page 87 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2020; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com