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21-100325-Drainage Technical Information Report (TIR)-01-29-2021-V1Woodbridge Building B Technical Information Report January 29, 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 01/29/2021 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 3.4 Upstream Basin Map Appendix A Basin Exhibits B Hydrology Model Output C Geotechnical Engineering Services Report \\esm8\engr\esm-jobs\1886\001\016-0011\document\rprt-003.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). Existing Site: The proposed Woodbridge Building B 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 proposed Building A project. 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 34 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. Most of the project site (including the entire Building A parcel) comprises a threshold discharge area (TDA), hereafter referred to as TDA 1, and drains to the south into the existing Stream EA. Stormwater runoff from the southwestern-most portion of the project site is in a separate TDA, hereafter referred to as TDA 2, which is shown on Figure 3.3 of this report. These areas are considered separate TDAs because the discharge from each does not converge within a quarter mile downstream of the project site. However, they do converge within 0.4 miles downstream of the project site and are part of the same overall East Hylebos Creek drainage basin (approximately 768 acres upstream of the point of convergence). Proposed Site Improvements: The proposed development consists of a single-story warehouse building with parking & landscaped areas around the building structure on a 16.85-acre parcel. The additional pedestrian connectivity improvements along the west side of Weyerhaeuser Way S (landscape planter and sidewalk) for Building A (previously submitted) are to be constructed with this project. Stormwater runoff from the proposed Building B and Building A (previously submitted) 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 Building B projects, the water quality and detention pond will either be constructed for both projects at one time, or with Building A, to then be extended to the south for the Building B 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 combined Buildings A and B development site conditions. Proposed Site Hydrology: The proposed onsite stormwater conveyance system will collect and convey runoff from the combined developed Building A and Building B project sites to a common detention facility. There will be two control structures in the detention facility to maintain proportionate discharge to the two natural discharge locations onsite. Discharge to the south through the existing 24-inch diameter CMP culvert beneath highway 18 is a natural discharge location for this portion of the project site. The other discharge location is to the southwest, into the Weyerhaeuser Pond outlet channel. 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. 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. Refer to the previously submitted Building A TIR for more information regarding the Level 3 Flow Control standard compliance. 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. Conservation flow control and enhanced water quality treatment for stormwater runoff will be provided within a detention pond and Modular Wetlands filter vaults (or approved equivalent) that will be located along the south and southwest boundaries of the project site following detention. The flow control facility will discharge from two control structures to maintain the existing natural discharge locations of the project site. One discharge location is to the south to existing Stream EA and the associated 24-inch diameter corrugated metal pipe (CMP) culvert, the other is to the southwest to the Weyerhaeuser Pond outlet channel. Both discharge locations eventually combine with the East Branch Hylebos Creek. 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: 8/30/2017 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 (GFGTCN9C[9#VJ#XG55WKVG('&'4#.9#;%#/275..%911&$4+&)'$7+.&+0)$ nWE Y E R H A E U S E R W A Y S .LOOP ROADLOOP ROADL L C Federal Way, WA 98003 33400 8th Ave S, Suite 205 C O N S U L T I N G E N G I N E E R S FEDERAL WAY CAMPUS LLC WOODBRIDGE BUILDING "B"SCALE: 1" = 200'FIGURE 1.3WEYERHAEUSER WAY S.WOODBRIDGEBUILDING "A"WOODBRIDGEBUILDING "B" 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 majority of the 16.85 acre Building B 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 Hylebos Creek, within 1/4 mile downstream. A portion of the existing Building B project site (3.78 acres) is estimated to drain to the southwest corner of that parcel to the Weyerhaeuser Pond outlet channel with a pre- developed forested 100-year flow rate of 0.384 cubic feet per second (cfs). The stormwater runoff from Building A and 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 combined proposed Building A and Building B development, the discharge from the detention pond will go to the same Stream EA location and to the Weyerhaeuser Pond outlet channel through 2 separate control structures. This outlet configuration will allow the developed site to drain proportionately to the existing natural discharge locations for the project site and satisfy Core Requirement No. 1. 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 10 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 Modular Wetlands filter vaults (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. Figure 3.4 shows the extent of the upstream basin (approximately 768 acres) tributary to the Point of Compliance which continues to the East Branch Hylebos Creek. The project site is located in primarily in Basin A with a small portion in Basin C. Basin A drains to Point 4 (shown on Figure 3.3), Basin B (North Lake) drains to the Weyerhaeuser Pond, and Basin C drains to Point 9 (shown on Figure 3.3). The project site is approximately 4% of the overall basin delineated on Figure 3.4. The Point of Compliance (shown beyond the southernmost point of Basin C) is approximately 1/2 mile downstream along the shortest drainage path from the project site. Task 2: Resource Review Flow Control Map According 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 (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 project site (3.78 acres) is estimated to drain to the southwest corner of that parcel to the Weyerhaeuser Pond outlet channel. The stormwater runoff combines approximately 1/2 mile downstream and continues to East Branch Hylebos Creek. 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 west 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: 8/30/2017 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 index contours - 100foot contours - 5 foot(below 1000 feet) and10 foot - Date: 8/30/2017 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 index contours - 100foot contours - 5 foot(below 1000 feet) and10 foot 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. Basin B (Approx. 376 Ac) Basin C (Approx. 228 Ac) Basin A (Approx. 164 Ac) Date: 6/27/2018User: SavannaN Building "B"Greenline Upstream Basin0750375 1 in = 750 ft Figure 3.4Data Source: Existing Stream / Creek provided by King County GIS (wtrcrs_line 2018).Aerial imagery provided by Aerial Express (2012).DEM provided by Puget Sound LiDAR Consortium.Although careful techniques are used in creating and displaying GIS data, ESM cannot guarantee accuracy of the information contained on this map. I-5 18 I-5 18 \\Esm8\engr\ESM-JOBS\1886\001\016-0011\gis\BuildingB_Upstream_Basin.mxd Legend Existing Stream / Creek Existing Site Flowplath Conceptual Future Site Proposed Building "B" Basin to Outlet Channel 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 34 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 thirteen 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. These wetlands have all been delineated and classified by the wetland biologist, Talasaea Consultants. The project is proposing to fill some small wetlands, with a proposed mitigation of enhancement and maintenance of existing hydrology for the existing wetlands and wetland creation in another location on the Weyerhaeuser Campus. For more information, see the Critical Areas Report, Building B by Talasaea Consultants, dated June 26, 2017, included with this submittal under separate cover. The stormwater runoff from a majority of the existing Building B drainage basin (TDA 1, 13.02 acres) is collected at the site’s southern boundary in Stream EA and routed to a 24- inch diameter CMP culvert beneath Highway 18. The remaining stormwater from the 3.78 acres within TDA 2 drains to the southwest and is collected in the Weyerhaeuser Pond outlet channel. Refer to Section 3 for more information. Developed Site Hydrology: The proposed drainage basins for Building A and Building B are detailed below 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 (4.78 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 areas within each TDA on Building B’s project site. For the combined proposed Building A and Building B development, the discharge from the detention pond will go to the same Stream EA location and to the Weyerhaeuser Pond outlet channel through 2 separate control structures. The detention facility is effectively a flow splitter in this configuration and will discharge proportionately based on the ratio of the existing TDA areas. TDA 1 will also include the areas from the Building A development for proper proportioning between TDA 1 and TDA 2. The frontage improvements along Weyerhaeuser Way S will be dispersed into the adjacent forest buffer, where practical, or to the existing stormwater conveyance system in the public ROW. Flow control for most of these surfaces will be achieved via sheet flow dispersion into the existing native vegetation and the proposed onsite detention facility over detains stormwater from the same basin. Most of these improvements are non- pollution generating surfaces (pervious and impervious) and will therefore not require additional water quality treatment. Table 4.1 – Buildings A & B with Frontage Improvements Pond Drainage Basin (Acres) Total Buildings A and B Developed Building A Right-of-way Areas for Building A & B (Not included in Total) Developed Building B - All TDAs Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Forest 8.86 1.15 0.00 7.71 3.91 1.15 0.00 2.76 0.00 0.00 0.00 0.00 4.95 0.00 0.00 4.95 Grass 2.25 2.09 0.16 0.00 1.32 1.16 0.16 0.00 0.98 0.01 0.97 0.00 0.93 0.93 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 10.11 10.11 0.00 0.00 5.19 5.19 0.00 0.00 0.00 0.00 0.00 0.00 4.92 4.92 0.00 0.00 Pavement 8.95 8.90 0.05 0.00 4.74 4.69 0.05 0.00 1.23 0.04 0.71 *0.48 4.21 4.21 0.00 0.00 Pervious 13.05 5.18 0.16 7.71 5.23 2.31 0.16 2.76 0.98 0.01 0.97 0.00 7.82 2.87 0.00 4.95 Impervious 19.06 19.01 0.05 0.00 9.93 9.88 0.05 0.00 1.23 0.04 0.71 *0.48 9.13 9.13 0.00 0.00 Total 32.11 24.19 0.21 7.71 15.16 12.19 0.21 2.76 2.21 0.05 1.68 *0.48 16.95 12.00 0.00 4.95 * Pedestrian connectivity improvements along Weyerhaeuser Way S Table 4.1 – Buildings A & B with Frontage Improvements Pond Drainage Basin (Acres) Total Buildings A and B Developed Building A Right-of-way Areas for Building A & B Developed Building B - All TDAs Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Forest 8.95 0.92 0.00 8.03 4.17 0.92 0.00 3.25 0.00 0.00 0.00 0.00 4.78 0.00 0.00 4.78 Grass 3.11 2.07 1.04 0.00 1.27 1.20 0.07 0.00 0.98 0.01 0.97 0.00 0.86 0.86 0.00 0.00 Pond Tract (Grass)2.05 2.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.05 2.05 0.00 0.00 Roof 10.14 10.14 0.00 0.00 5.19 5.19 0.00 0.00 0.00 0.00 0.00 0.00 4.95 4.95 0.00 0.00 Pavement 10.27 9.01 0.78 0.48 4.83 4.76 0.07 0.00 1.23 0.04 0.71 *0.48 4.21 4.21 0.00 0.00 Pervious 14.11 5.04 1.04 8.03 5.44 2.12 0.07 3.25 0.98 0.01 0.97 0.00 7.69 2.91 0.00 4.78 Impervious 20.41 19.15 0.78 0.48 10.02 9.95 0.07 0.00 1.23 0.04 0.71 *0.48 9.16 9.16 0.00 0.00 Total **34.52 24.19 1.82 8.51 15.46 12.07 0.14 3.25 **2.21 0.05 1.68 *0.48 16.85 12.07 0.00 4.78 * 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 – Building B TDA Summary Pond Drainage Basin (Acres) Developed Building B - All TDAs Developed Building B - TDA 1 Developed Building B - TDA 2 Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Total Detained Bypass Un-Detained Forest 4.78 0.00 0.00 4.78 3.74 0.00 0.00 3.74 1.04 0.00 0.00 1.04 Grass 0.86 0.86 0.00 0.00 0.60 0.60 0.00 0.00 0.26 0.26 0.00 0.00 Pond Tract (Grass)2.05 2.05 0.00 0.00 0.46 0.46 0.00 0.00 1.59 1.59 0.00 0.00 Roof 4.95 4.95 0.00 0.00 4.69 4.69 0.00 0.00 0.26 0.26 0.00 0.00 Pavement 4.21 4.21 0.00 0.00 3.53 3.53 0.00 0.00 0.68 0.68 0.00 0.00 Pervious 7.69 2.91 0.00 4.78 4.80 1.06 0.00 3.74 2.89 1.85 0.00 1.04 Impervious 9.16 9.16 0.00 0.00 8.22 8.22 0.00 0.00 0.94 0.94 0.00 0.00 Total 16.85 12.07 0.00 4.78 13.02 9.28 0.00 3.74 3.83 2.79 0.00 1.04 * Since both developed TDAs drain to a single detention facility and mix together, the detention control structure has been sized with the developed totals listed in Table 4.1 above. The final control structure orifice design that discharges to each TDA will use the ratio of the detained TDA 2 area to the total detained site area (2.79 Acres : 24.19 Acres, TDA 2 discharge is therefore 11.5% of the total discharge of POC 1 in the WWHM output). Refer to Table 4.2A below. Table 4.2A – Control Structure Split Riser Design Total TDA 1 TDA 2 Diameter (width, in.)Area Stage Elevation Diameter (width, in.)Area Stage Elevation Diameter (width, in.)Area Stage Elevation Orifice 1 2.42 4.600 0 2.266 4.033 0 0.849 0.566 0 Orifice 2 2.90 6.605 4.6 2.716 5.794 4.6 1.017 0.812 4.6 Orifice 3 2.00 3.142 5.2 1.873 2.755 5.2 0.701 0.386 5.2 Notch*1.50 N/A 6.25 1.25 N/A 6.25 0.25 N/A 6.25 * Mininum allowed notch width for TDA 2 is 0.25 inches, the remainder of the split is added to the TDA 1 notch width Performance Standards: Stormwater systems onsite are to be designed to mitigate runoff generated from the project per the requirements of the SWDM, specifically the Flow Control Duration 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 Western Washington Hydrology Model (WWHM). Due to the size and location of the proposed development, the project is required to comply with Flow Control Duration standards per Section 1.2.3.1.B of the SWDM. here 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. T 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 Modular Wetlands filter vaults (or approved equivalent), as described in this section under Water Quality System. Flow Control System: Onsite: Onsite flow control will be provided with a detention pond and two separate control structures. Each control structure will discharge to the TDA for which it is proportioned. The proportion of each control structure is based on the area of a particular TDA compared to the area of all TDAs combined. The sizing from WWHM complies with the Conservation Flow Control standards and 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 0.5 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 10 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 Building B projects, the water quality and detention pond will either be constructed for both projects at one time, or with Building A, to then be extended to the south, for the Building B development. The sizing of each control structure is proportionate to the existing TDA to which it discharges. The required detention volume for the project site has been calculated with a single control structure, as detailed in the WWHM output in Appendix B of this report. The orifice area ratios for the dual outlet control structures are proportional to the tributary area ratio between TDA 1 and TDA 2; therefore, orifice area ratio to be used for each TDA is the area of that TDA divided by the total site area. Offsite: Most of the frontage improvements along the west side of Weyerhaeuser Way S will be dispersed into a native vegetated area, the remainder will be collected in the existing stormwater conveyance system in the public ROW. The frontage improvements along the east side of Weyerhaeuser Way S will be collected in the existing stormwater conveyance system in the public ROW. The existing stormwater conveyance system has been evaluated for conveyance capacity and backwater containment and is sufficient for the proposed development. These improvements are modeled as bypass and comply with the standards specified in Section 1.2.3.2.E of the SWDM. ·The point of convergence for the frontage improvement area is the TDA 1 discharge location (Stream EA) which is within a quarter-mile downstream of the project site ·The flow rate increase over the existing site condition of the bypassed target surfaces is less than 0.4 cfs ·The drainage system downstream of the bypassed area is well established and the flows from the improvements will not create a significant adverse impact ·The majority of the improvements are non-pollution generating and will not require water quality treatment, and ·Compensatory mitigation is provided by the onsite flow control system to account for the offsite frontage improvements as areas that bypass detention, as shown on the schematic in the Hydrology Model output included in Appendix B of this report. The WWHM output for Flow Control for the combined Buildings A and B is provided in Appendix B. Table 4.3 Return Period Predeveloped Combined ( cfs ) Mitigated Combined ( cfs ) 2 Year 0.7647 0.6662 5 Year 1.2010 0.9105 10 Year 1.4482 1.0905 25 Year 1.7102 1.3398 50 Year 1.8732 1.5417 100 Year 2.0101 1.7582 Table 4.4 Stormwater Detention Volume Total Combined (Cu Ft) Required 413,100 Provided 442,000 Safety Factor 7% Water Quality System: Water quality treatment will be provided in Modular Wetlands filter vaults (or approved equivalent) after the detention pond, per Section 1.2.8 of the SWDM. Depending on timing for design and construction of the Building A and Building B projects, the filter vaults will either be constructed for both projects at one time, or with Building A, to then be upsized for the Building B development. The water quality treatment facility’s required and provided flow rates (following detention) for TDA 1 & TDA 2 are given in Table 4.5. The WWHM Water Quality output was calculated from the 801 – Mitigated Flow time series file. The project site requires enhanced water quality treatment which can be provided per SWDM using one of three different options. The current proposed design treats stormwater after detention in one of two Modular Wetlands vaults. TDA 1 will have an 8x24 vault while TDA 2 will have a 4x8 vault. Table 4.5 Water Quality Total Flow ( cfs ) TDA 1 Flow ( cfs ) TDA 2 Flow ( cfs ) Required 0.666 0.590 0.077 Provided -0.693 0.115 Model Designation -MWS-L-8-24-V MWS-L-4-8-V 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. Oil control is required for the parking lot areas and implementation details will be provided in the final TIR. In summary, enhanced water quality treatment will be provided for Building A and Building B using Modular Wetlands filter vaults (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). The WWHM output for Water Quality is provided in Appendix B. The frontage improvements along the Weyerhaeuser Way S are non-pollution generating and the resulting runoff is considered clean which will not need water quality treatment. Flow Control BMPs Flow control BMPs were evaluated for the Building B 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 – 1.70 acres. Full Dispersion Within the proposed project area, the native vegetated areas to the west are above the proposed development and are not available for dispersion. The remaining native vegetated areas along the east parcel boundary are not large enough to accommodate a minimum flowpath of 100 feet in length. 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. For frontage improvements along the west side of Weyerhaeuser Way S, dispersion will be used where feasible. 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 Bioretention (specified in Section C.2.6) may be feasible, using raingardens pending further geotechnical field investigation (to be completed with final design). Permeable Pavement, Permeable Pavement (specified in Section C.2.7) may feasible for the onsite and frontage non-pollution generating impervious concrete sidewalks and will be analyzed in detail with final design. 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) may be feasible for very small impervious areas above the managed forest buffer to the east and will be evaluated with final design. 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 total Building B undisturbed native vegetation area is 4.78 acres. That area mitigates for 1.35 acres of impervious area which is equivalent to 14.7 percent of the total Building B impervious area. The native vegetated area used for this credit requires specific covenants, per SWDM, and these requirements have been preliminarily 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 appears to be feasible for the project site and will be confirmed with final design. 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 will be added on the final landscape plans). Roof Downspout Minimum Requirement #7 All roof downspouts will be 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, the project site will implement the following flow control BMPs: Perforated Pipe Connection for roof downspouts and amend soils in landscaped areas. If the impervious area credited as mitigated is not sufficient, a fee in lieu will be paid, or the Native Growth Retention Credit will be implemented. 5. Conveyance System Analysis and Design Onsite Conveyance System: Runoff from the developed project site will be collected from the developed lot lawns, roofs, and sidewalks by the conveyance system located in the ROW. The proposed stormwater drainage system is composed of catch basin structures with connecting pipes. A conveyance and backwater analysis will be completed to verify the capacity of the critical pipes in the system. The proposed stormwater drainage system will be designed to convey the 25-year peak flow rate generated by the developed tributary basin as required in the SWDM. The system will contain the 100-year flow within the catch basin without any conveyance or backwater issues. Detailed conveyance calculations will be provided with the final TIR. Outlet Conveyance System: The water quality and 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 cfs, using the field verified slope of 3.82% and a Manning’s n of 0.013. The total maximum 24.19-acre drainage basin mitigated 100-year flow from the detention pond is 2.0 cubic-feet per second. Therefore, the existing 24-inch CMP culvert has sufficient capacity to accommodate the combined proposed development of Buildings A and B. Conveyance Calculation, Woodbridge Building "B" 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 10.17 12.40 24 2 3.142 6.283 0.500 0.012 0.013 24.95 7.94 41%50% CB #5 to CB #4 0.00 0.00 0.00 7.97 9.72 24 2 3.142 6.283 0.500 0.005 0.013 16.07 5.11 50%60% CB #6 to CB #5 0.00 0.00 0.00 6.74 8.22 24 2 3.142 6.283 0.500 0.005 0.013 16.22 5.16 42%51% CB #7 to CB #6 0.00 0.00 0.00 6.74 8.22 18 1.5 1.767 4.712 0.375 0.005 0.013 7.47 4.23 90%110% CB #8 to CB #7 0.00 0.00 0.00 6.74 8.22 18 1.5 1.767 4.712 0.375 0.005 0.013 7.46 4.22 90%110% CB #9 to CB #8 0.00 0.00 0.00 6.74 8.22 18 1.5 1.767 4.712 0.375 0.005 0.013 7.46 4.22 90%110% CB #10 to CB #9 0.00 0.00 0.00 6.74 8.22 18 1.5 1.767 4.712 0.375 0.005 0.013 7.49 4.24 90%110% 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 #33 to CB #9 0.00 0.00 0.00 1.85 2.25 12 1 0.785 3.142 0.250 0.146 0.013 13.67 17.40 14%16% CB #34 to CB #33 0.12 2.87 2.99 1.85 2.25 12 1 0.785 3.142 0.250 0.012 0.013 3.95 5.03 47%57% CB #35 to CB #4 0.00 0.00 0.00 2.20 2.69 12 1 0.785 3.142 0.250 0.129 0.013 12.82 16.32 17%21% CB #36 to CB #35 0.00 0.00 0.00 2.20 2.69 12 1 0.785 3.142 0.250 0.011 0.013 3.72 4.73 59%72% CB #37 to CB #36 0.00 0.00 0.00 2.20 2.69 12 1 0.785 3.142 0.250 0.005 0.013 2.53 3.22 87%106% CB #38 to CB #37 0.00 0.00 0.00 2.20 2.69 12 1 0.785 3.142 0.250 0.005 0.013 2.53 3.22 87%106% CB #39 to CB #38 0.00 0.00 0.00 2.20 2.69 12 1 0.785 3.142 0.250 0.005 0.013 2.54 3.23 87%106% CB #40 to CB #39 0.00 0.00 0.00 2.20 2.69 12 1 0.785 3.142 0.250 0.005 0.013 2.55 3.24 87%106% CB #41 to CB #40 0.45 3.33 3.78 2.20 2.69 12 1 0.785 3.142 0.250 0.005 0.013 2.51 3.20 88%107% CB #42 to Oil/Water Sep 0.00 0.00 0.00 1.23 1.50 12 1 0.785 3.142 0.250 0.034 0.013 6.59 8.39 19%23% CB #43 to CB #42 0.00 0.00 0.00 1.23 1.50 12 1 0.785 3.142 0.250 0.005 0.013 2.53 3.22 49%59% CB #44 to CB #43 0.00 1.93 1.93 1.23 1.50 12 1 0.785 3.142 0.250 0.005 0.013 2.53 3.22 49%59% Oil/Water Sep to CB #5 0.00 0.00 0.00 1.23 1.50 12 1 0.785 3.142 0.250 0.115 0.013 12.10 15.40 10%12% \\esm8\engr\esm-jobs\1886\001\016-0011\StormReport\Documents\Calcs-210 - Conveyance Design - V2.0.4.xlsx 4:28 PM 1/27/2021 Backwater Calculation, Woodbridge Building "B" 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) Oil/Water Sep to CB #5 1.5 15 12 0.011 376.3 378.0 0.79 1.90 0.06 384.1 0.02 384.1 0.37 0.06 384.5 378.8 0.06 0.41 0.00 384.9 390.0 5.1 CB #44 to CB #43 1.5 250 12 0.011 384.4 385.6 0.79 1.90 0.06 385.6 0.31 385.9 0.03 0.06 386.0 386.4 0.00 0.00 0.00 386.4 390.6 4.2 CB #43 to CB #42 1.5 250 12 0.011 383.1 384.4 0.79 1.90 0.06 385.2 0.31 385.5 0.03 0.06 385.6 385.2 0.06 0.07 0.00 385.6 389.4 3.8 CB #42 to Oil/Water Sep 1.5 150 12 0.011 378.0 383.1 0.79 1.90 0.06 384.9 0.19 385.1 0.03 0.06 385.2 383.9 0.06 0.07 0.00 385.2 388.1 2.9 CB #41 to CB #40 2.7 109 12 0.011 388.9 389.5 0.79 3.42 0.18 390.9 0.44 391.3 0.09 0.18 391.6 390.6 0.00 0.00 0.00 391.4 394.5 3.1 CB #40 to CB #39 2.7 126 12 0.011 388.3 388.9 0.79 3.42 0.18 390.0 0.51 390.5 0.09 0.18 390.8 390.1 0.18 0.24 0.00 390.9 394.6 3.7 CB #39 to CB #38 2.7 212 12 0.011 387.2 388.3 0.79 3.42 0.18 388.8 0.86 389.7 0.09 0.18 390.0 389.4 0.18 0.24 0.00 390.0 394.3 4.3 CB #35 to CB #4 2.7 82 12 0.011 374.8 385.3 0.79 3.42 0.18 383.5 0.33 383.8 0.09 0.18 384.1 386.4 0.18 0.24 0.00 386.4 388.1 1.7 CB #34 to CB #33 2.3 178 12 0.011 389.5 391.7 0.79 2.87 0.13 390.5 0.50 391.0 0.06 0.13 391.2 392.7 0.00 0.00 0.00 392.5 394.4 1.8 CB #33 to CB #9 2.3 60 12 0.011 380.7 389.5 0.79 2.87 0.13 389.7 0.17 389.8 0.06 0.13 390.0 390.4 0.13 0.17 0.00 390.5 392.2 1.7 CB #11 to CB #10 6.0 82 18 0.011 381.1 381.5 1.77 3.38 0.18 390.6 0.19 390.7 0.09 0.18 391.0 383.0 0.00 0.00 0.00 390.8 395.3 4.5 CB #10 to CB #9 8.2 81 18 0.011 380.7 381.1 1.77 4.65 0.34 389.7 0.35 390.0 0.17 0.34 390.5 383.0 0.18 0.23 0.15 390.6 391.0 0.5 CB #9 to CB #8 8.2 285 18 0.011 379.3 380.7 1.77 4.65 0.34 387.8 1.24 389.1 0.17 0.34 389.6 382.6 0.34 0.44 0.00 389.7 391.0 1.4 CB #8 to CB #7 8.2 285 18 0.011 377.9 379.3 1.77 4.65 0.34 386.0 1.24 387.2 0.17 0.34 387.7 381.2 0.34 0.44 0.00 387.8 390.0 2.1 CB #7 to CB #6 8.2 169 18 0.011 377.0 377.9 1.77 4.65 0.34 384.6 0.73 385.4 0.17 0.34 385.9 379.7 0.34 0.44 0.00 386.0 388.6 2.7 CB #6 to CB #5 8.2 45 24 0.011 376.3 376.5 3.14 2.62 0.11 384.1 0.04 384.1 0.05 0.11 384.3 378.1 0.34 0.44 0.00 384.6 387.4 2.8 CB #5 to CB #4 9.7 305 24 0.011 374.8 376.3 3.14 3.09 0.15 383.5 0.40 383.9 0.07 0.15 384.1 378.0 0.11 0.14 0.00 384.1 387.5 3.4 CB #4 to Pond 12.4 62 24 0.011 374.0 374.8 3.14 3.95 0.24 383.0 0.13 383.1 0.12 0.24 383.5 376.7 0.18 0.24 0.00 383.5 390.7 7.2 \\esm8\engr\esm-jobs\1886\001\016-0011\StormReport\Documents\Calcs-210 - Conveyance Design - V2.0.4.xlsx 4:28 PM 1/27/2021 nWEYERHAEUSER WAY S.WE Y E R H A E U S E R W A Y S .LOOP ROADL L C Federal Way, WA 98003 33400 8th Ave S, Suite 205 C O N S U L T I N G E N G I N E E R S FEDERAL WAY CAMPUS LLC WOODBRIDGE BUILDING "B"SCALE: 1" = 200'LEGENDFIGURE 5.1 WWHM2012 PROJECT REPORT Woodbridge Bldg B 1/27/2021 3:56:20 PM Page 2 General Model Information Project Name:Woodbridge Bldg B Site Name:Woodbridge Building B - Conveyance Site Address: City:Federal Way Report Date:1/27/2021 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 POC5:50 Percent of the 2 Year High Flow Threshold for POC5:50 Year Low Flow Threshold for POC34:50 Percent of the 2 Year High Flow Threshold for POC34:50 Year Low Flow Threshold for POC41:50 Percent of the 2 Year High Flow Threshold for POC41:50 Year Low Flow Threshold for POC44:50 Percent of the 2 Year High Flow Threshold for POC44:50 Year Woodbridge Bldg B 1/27/2021 3:56:20 PM Page 7 Mitigated Land Use CB #44 (to Oil/Water Sep) Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 1.929 Impervious Total 1.929 Basin Total 1.929 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg B 1/27/2021 3:56:20 PM Page 8 CB #34 - North Parking Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.125 Pervious Total 0.125 Impervious Land Use acre ROADS FLAT 2.866 Impervious Total 2.866 Basin Total 2.991 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg B 1/27/2021 3:56:20 PM Page 9 CB #41 - West Parking Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.45 Pervious Total 0.45 Impervious Land Use acre ROADS FLAT 3.33 Impervious Total 3.33 Basin Total 3.78 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg B 1/27/2021 3:56:20 PM Page 10 CB #5 - South Parking Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.074 Pervious Total 0.074 Impervious Land Use acre ROADS FLAT 1.011 Impervious Total 1.011 Basin Total 1.085 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg B 1/27/2021 3:56:20 PM Page 17 POC 5 + Predeveloped x Mitigated Mitigated Landuse Totals for POC #5 Total Pervious Area:0.074 Total Impervious Area:1.011 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Mitigated. POC #5 Return Period Flow(cfs) 2 year 0.390223 5 year 0.494479 10 year 0.565489 25 year 0.657778 50 year 0.728534 100 year 0.801104 Woodbridge Bldg B 1/27/2021 3:57:14 PM Page 53 POC 34 + Predeveloped x Mitigated Mitigated Landuse Totals for POC #34 Total Pervious Area:0.125 Total Impervious Area:2.866 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Mitigated. POC #34 Return Period Flow(cfs) 2 year 1.100765 5 year 1.39303 10 year 1.591894 25 year 1.850145 50 year 2.048002 100 year 2.250823 Woodbridge Bldg B 1/27/2021 3:57:46 PM Page 67 POC 41 + Predeveloped x Mitigated Mitigated Landuse Totals for POC #41 Total Pervious Area:0.45 Total Impervious Area:3.33 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Mitigated. POC #41 Return Period Flow(cfs) 2 year 1.298484 5 year 1.650022 10 year 1.889977 25 year 2.202364 50 year 2.442221 100 year 2.688517 Woodbridge Bldg B 1/27/2021 3:58:17 PM Page 77 POC 44 + Predeveloped x Mitigated Mitigated Landuse Totals for POC #44 Total Pervious Area:0 Total Impervious Area:1.929 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Mitigated. POC #44 Return Period Flow(cfs) 2 year 0.735459 5 year 0.92897 10 year 1.060448 25 year 1.230993 50 year 1.361524 100 year 1.495224 Woodbridge Bldg B 1/27/2021 3:58:46 PM Page 89 Mitigated Schematic Woodbridge Bldg B 1/27/2021 3:58:46 PM Page 102 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. 2005-2021; 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 Revised Geotechnical Engineering Services Report by GeoEngineers dated June 21, 2018, is included in Appendix C. The Critical Areas Report, Building B by Talasaea Consultants, dated June 26, 2017, is included with this submittal under separate cover. 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 pond are provided in this section of the report. Due to topography and the proposed site design, a single sediment pond will be used to collect and treat runoff from the construction area. The construction of the project site will be such that the sediment pond will receive flows from within the limits of disturbance. Due to the nature of the land use alterations, the land use type used for the TESC calculations is fully developed land cover and the peak storm event selected for sizing is the 2-year, 15-minute, 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. Woodbridge Building B Temporary Erosion and Sediment Control Plan (TESCP) Sediment Pond Parameters Developed Basin Maximum basin contributing area (acres)12.07 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 0.070 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 3.58 Minimum Dewatering Tube Diameter (inches)6.00 Sediment Pond Sizing Developed Basin Facility Top Elev.389.5 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)12.07 Developed 2-year Flow, 15-minute timesteps (cfs)3.6782 Design Pond Surface Area (square feet)7663 Provided Pond Surface Area (square feet)As 7755 Table for Plans Developed Basin Bottom Width (Bottom of Sediment Storage)17.0 Bottom Length (Bottom of Sediment Storage)135.0 Top Width (Top of Berm)59.0 Top Length (Top of Berm)177.0 Length:Width 3:1 Side Slopes 3:1 Spillway Width (1-ft total depth, 0.5-ft flow depth)6.00 Over. Elev.388.5 Top Riser Pipe Elev 387.5 Bottom Elev.382.5 Top Berm Elev.389.5 Orifice Diameter (inch)3.58 Riser Size (inch)12 9. Bond Quantities, Facility Summaries, and Declaration of Covenant The Bond Quantities worksheet will be provided in this section of the final report. 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-8-24-V PLAN VIEW ELEVATION VIEW RIGHT END VIEW LEFT END VIEW GENERAL NOTES INSTALLATION NOTES SITE SPECIFIC DATA STANDARD DETAIL STORMWATER BIOFILTRATION SYSTEM MWS-L-4-8-V PLAN VIEW ELEVATION VIEW RIGHT END VIEW LEFT END VIEW GENERAL NOTES INSTALLATION NOTES SITE SPECIFIC DATA Appendix A nWEYERHAEUSER WAY S.WE Y E R H A E U S E R W A Y S .LOOP ROADWOODBRIDGEBUILDING "A"L L C Federal Way, WA 98003 33400 8th Ave S, Suite 205 C O N S U L T I N G E N G I N E E R S FEDERAL WAY CAMPUS LLC WOODBRIDGE BUILDING "B"SCALE: 1" = 200'LEGENDWOODBRIDGEBUILDING "B" Appendix B WWHM2012 PROJECT REPORT Woodbridge Bldg B 1/26/2021 4:09:57 PM Page 2 General Model Information Project Name:Woodbridge Bldg B Site Name:Woodbridge Building B - Detention & WQ Site Address: City:Federal Way Report Date:1/26/2021 Gage:Seatac Data Start:1948/10/01 00:00 Data End:2009/09/30 00:00 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 Low Flow Threshold for POC3:50 Percent of the 2 Year High Flow Threshold for POC3:50 Year Low Flow Threshold for POC5:50 Percent of the 2 Year High Flow Threshold for POC5:50 Year Woodbridge Bldg B 1/26/2021 4:09:57 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 B 1/26/2021 4:09:57 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 B 1/26/2021 4:09:57 PM Page 5 PreDev - Building A & B ROW - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.05 Pervious Total 0.05 Impervious Land Use acre Impervious Total 0 Basin Total 0.05 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg B 1/26/2021 4:09:57 PM Page 6 PreDev - Building A & B ROW - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 1.68 Pervious Total 1.68 Impervious Land Use acre Impervious Total 0 Basin Total 1.68 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg B 1/26/2021 4:09:57 PM Page 7 PreDev - Building B - 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 B 1/26/2021 4:09:57 PM Page 8 PreDev - Building B - Oil/Water Sep Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 4.21 Impervious Total 4.21 Basin Total 4.21 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg B 1/26/2021 4:09:57 PM Page 9 PreDev - Building A & B 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 B 1/26/2021 4:09:57 PM Page 10 PreDev - Building B - TESC Pond Areas - With Final Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 2.91 Pervious Total 2.91 Impervious Land Use acre ROADS FLAT 9.16 Impervious Total 9.16 Basin Total 12.07 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg B 1/26/2021 4:09:57 PM Page 11 Mitigated Land Use Dev - Building B - Detained Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 2.91 Pervious Total 2.91 Impervious Land Use acre ROADS FLAT 4.21 ROOF TOPS FLAT 4.95 Impervious Total 9.16 Basin Total 12.07 Element Flows To: Surface Interflow Groundwater Detention Pond - 2:1 SSDetention Pond - 2:1 SS Woodbridge Bldg B 1/26/2021 4:09:57 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 SSDetention Pond - 2:1 SS Woodbridge Bldg B 1/26/2021 4:09:57 PM Page 13 Dev - Building A & B 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 SSDetention Pond - 2:1 SS Woodbridge Bldg B 1/26/2021 4:09:57 PM Page 14 Dev - Building A & B ROW - Bypass Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.97 Pervious Total 0.97 Impervious Land Use acre ROADS FLAT 0.71 Impervious Total 0.71 Basin Total 1.68 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg B 1/26/2021 4:09:57 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 B 1/26/2021 4:09:57 PM Page 16 Dev - Building B - Oil/Water Sep Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 4.21 Impervious Total 4.21 Basin Total 4.21 Element Flows To: Surface Interflow Groundwater Woodbridge Bldg B 1/26/2021 4:09:57 PM Page 17 Dev - Building A & B 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 B 1/26/2021 4:09:57 PM Page 19 Mitigated Routing Detention Pond - 2:1 SS Bottom Length:237.00 ft. Bottom Width:200.00 ft. Depth:9 ft. Volume at riser head:9.4826 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:0.125 ft. Notch Height:1.250 ft. Orifice 1 Diameter:2.42 in.Elevation:0 ft. Orifice 2 Diameter:2.9 in.Elevation:4.6 ft. Orifice 3 Diameter:2 in.Elevation:5.2 ft. Element Flows To: Outlet 1 Outlet 2 Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 1.088 0.000 0.000 0.000 0.1000 1.092 0.109 0.050 0.000 0.2000 1.096 0.218 0.071 0.000 0.3000 1.100 0.328 0.087 0.000 0.4000 1.104 0.438 0.100 0.000 0.5000 1.108 0.549 0.112 0.000 0.6000 1.112 0.660 0.123 0.000 0.7000 1.116 0.771 0.133 0.000 0.8000 1.120 0.883 0.142 0.000 0.9000 1.124 0.995 0.150 0.000 1.0000 1.128 1.108 0.158 0.000 1.1000 1.132 1.221 0.166 0.000 1.2000 1.136 1.334 0.174 0.000 1.3000 1.140 1.448 0.181 0.000 1.4000 1.145 1.563 0.188 0.000 1.5000 1.149 1.677 0.194 0.000 1.6000 1.153 1.792 0.201 0.000 1.7000 1.157 1.908 0.207 0.000 1.8000 1.161 2.024 0.213 0.000 1.9000 1.165 2.140 0.219 0.000 2.0000 1.169 2.257 0.224 0.000 2.1000 1.174 2.374 0.230 0.000 2.2000 1.178 2.492 0.235 0.000 2.3000 1.182 2.610 0.241 0.000 2.4000 1.186 2.728 0.246 0.000 2.5000 1.190 2.847 0.251 0.000 2.6000 1.195 2.967 0.256 0.000 2.7000 1.199 3.086 0.261 0.000 2.8000 1.203 3.206 0.265 0.000 2.9000 1.207 3.327 0.270 0.000 Woodbridge Bldg B 1/26/2021 4:09:57 PM Page 20 3.0000 1.211 3.448 0.275 0.000 3.1000 1.216 3.569 0.279 0.000 3.2000 1.220 3.691 0.284 0.000 3.3000 1.224 3.813 0.288 0.000 3.4000 1.228 3.936 0.293 0.000 3.5000 1.233 4.059 0.297 0.000 3.6000 1.237 4.183 0.301 0.000 3.7000 1.241 4.307 0.305 0.000 3.8000 1.245 4.431 0.309 0.000 3.9000 1.250 4.556 0.313 0.000 4.0000 1.254 4.681 0.317 0.000 4.1000 1.258 4.807 0.321 0.000 4.2000 1.263 4.933 0.325 0.000 4.3000 1.267 5.059 0.329 0.000 4.4000 1.271 5.186 0.333 0.000 4.5000 1.276 5.314 0.337 0.000 4.6000 1.280 5.442 0.340 0.000 4.7000 1.284 5.570 0.416 0.000 4.8000 1.289 5.699 0.450 0.000 4.9000 1.293 5.828 0.476 0.000 5.0000 1.298 5.957 0.499 0.000 5.1000 1.302 6.087 0.520 0.000 5.2000 1.306 6.218 0.539 0.000 5.3000 1.311 6.349 0.591 0.000 5.4000 1.315 6.480 0.622 0.000 5.5000 1.320 6.612 0.648 0.000 5.6000 1.324 6.744 0.673 0.000 5.7000 1.328 6.877 0.695 0.000 5.8000 1.333 7.010 0.716 0.000 5.9000 1.337 7.143 0.737 0.000 6.0000 1.342 7.277 0.756 0.000 6.1000 1.346 7.412 0.775 0.000 6.2000 1.351 7.547 0.792 0.000 6.3000 1.355 7.682 0.814 0.000 6.4000 1.360 7.818 0.850 0.000 6.5000 1.364 7.954 0.893 0.000 6.6000 1.369 8.091 0.939 0.000 6.7000 1.373 8.228 0.989 0.000 6.8000 1.378 8.365 1.041 0.000 6.9000 1.382 8.503 1.094 0.000 7.0000 1.387 8.642 1.149 0.000 7.1000 1.391 8.781 1.204 0.000 7.2000 1.396 8.920 1.260 0.000 7.3000 1.400 9.060 1.320 0.000 7.4000 1.405 9.200 1.385 0.000 7.5000 1.409 9.341 1.453 0.000 7.6000 1.414 9.482 2.137 0.000 7.7000 1.418 9.624 3.366 0.000 7.8000 1.423 9.766 4.913 0.000 7.9000 1.428 9.909 6.639 0.000 8.0000 1.432 10.05 8.404 0.000 8.1000 1.437 10.19 10.06 0.000 8.2000 1.441 10.33 11.50 0.000 8.3000 1.446 10.48 12.64 0.000 8.4000 1.451 10.62 13.45 0.000 8.5000 1.455 10.77 14.04 0.000 8.6000 1.460 10.92 14.80 0.000 8.7000 1.465 11.06 15.40 0.000 Woodbridge Bldg B 1/26/2021 4:09:57 PM Page 22 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:26.01 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:6.08 Total Impervious Area:19.93 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.764716 5 year 1.201016 10 year 1.448274 25 year 1.710223 50 year 1.872318 100 year 2.010187 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.666175 5 year 0.91049 10 year 1.090548 25 year 1.339756 50 year 1.541747 100 year 1.758257 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.751 0.743 1950 0.937 0.772 1951 1.684 1.277 1952 0.531 0.442 1953 0.429 0.496 1954 0.659 0.525 1955 1.051 0.579 1956 0.836 0.803 1957 0.675 0.656 1958 0.760 0.501 Woodbridge Bldg B 1/26/2021 4:10:30 PM Page 23 1959 0.652 0.491 1960 1.139 1.020 1961 0.642 0.790 1962 0.400 0.416 1963 0.549 0.550 1964 0.722 0.581 1965 0.517 0.700 1966 0.497 0.532 1967 1.040 0.782 1968 0.649 0.668 1969 0.635 0.598 1970 0.523 0.540 1971 0.560 0.666 1972 1.254 1.026 1973 0.570 0.667 1974 0.618 0.626 1975 0.838 0.678 1976 0.606 0.548 1977 0.072 0.494 1978 0.531 0.554 1979 0.321 0.554 1980 1.188 0.966 1981 0.475 0.597 1982 0.914 1.225 1983 0.819 0.570 1984 0.506 0.448 1985 0.300 0.558 1986 1.325 0.638 1987 1.172 0.974 1988 0.463 0.474 1989 0.302 0.441 1990 2.451 1.305 1991 1.476 1.083 1992 0.569 0.500 1993 0.593 0.401 1994 0.199 0.375 1995 0.850 0.689 1996 1.792 1.174 1997 1.498 1.252 1998 0.339 0.561 1999 1.405 0.969 2000 0.591 0.604 2001 0.106 0.546 2002 0.648 0.830 2003 0.827 0.637 2004 1.070 1.209 2005 0.768 0.587 2006 0.905 0.816 2007 1.820 1.829 2008 2.347 1.274 2009 1.152 0.832 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 2.4513 1.8290 2 2.3472 1.3048 3 1.8196 1.2774 Woodbridge Bldg B 1/26/2021 4:10:30 PM Page 24 4 1.7918 1.2741 5 1.6840 1.2524 6 1.4979 1.2247 7 1.4760 1.2090 8 1.4046 1.1742 9 1.3255 1.0832 10 1.2541 1.0264 11 1.1885 1.0199 12 1.1724 0.9741 13 1.1525 0.9686 14 1.1386 0.9662 15 1.0702 0.8316 16 1.0509 0.8299 17 1.0398 0.8163 18 0.9367 0.8031 19 0.9135 0.7899 20 0.9054 0.7817 21 0.8502 0.7721 22 0.8377 0.7431 23 0.8363 0.6999 24 0.8266 0.6889 25 0.8190 0.6780 26 0.7678 0.6676 27 0.7603 0.6674 28 0.7512 0.6661 29 0.7223 0.6565 30 0.6749 0.6381 31 0.6591 0.6371 32 0.6522 0.6256 33 0.6486 0.6037 34 0.6479 0.5981 35 0.6424 0.5965 36 0.6346 0.5865 37 0.6183 0.5808 38 0.6056 0.5792 39 0.5929 0.5703 40 0.5913 0.5611 41 0.5696 0.5576 42 0.5693 0.5541 43 0.5596 0.5538 44 0.5487 0.5497 45 0.5314 0.5477 46 0.5307 0.5462 47 0.5233 0.5400 48 0.5172 0.5318 49 0.5056 0.5251 50 0.4972 0.5005 51 0.4750 0.5000 52 0.4626 0.4964 53 0.4292 0.4944 54 0.3997 0.4906 55 0.3388 0.4735 56 0.3211 0.4476 57 0.3019 0.4421 58 0.3000 0.4412 59 0.1993 0.4162 60 0.1060 0.4013 61 0.0721 0.3753 Woodbridge Bldg B 1/26/2021 4:10:30 PM Page 26 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.3824 17597 16401 93 Pass 0.3974 16196 14414 88 Pass 0.4125 14994 13045 87 Pass 0.4275 13879 12057 86 Pass 0.4426 12842 11120 86 Pass 0.4576 11852 10284 86 Pass 0.4727 10936 9516 87 Pass 0.4877 10149 8829 86 Pass 0.5028 9415 8168 86 Pass 0.5178 8763 7542 86 Pass 0.5329 8177 6898 84 Pass 0.5479 7627 6222 81 Pass 0.5630 7090 5655 79 Pass 0.5780 6588 5208 79 Pass 0.5931 6147 4922 80 Pass 0.6081 5779 4648 80 Pass 0.6232 5433 4400 80 Pass 0.6382 5103 4143 81 Pass 0.6533 4810 3897 81 Pass 0.6683 4528 3640 80 Pass 0.6834 4259 3433 80 Pass 0.6984 4021 3240 80 Pass 0.7135 3792 3044 80 Pass 0.7285 3553 2823 79 Pass 0.7436 3343 2599 77 Pass 0.7586 3142 2389 76 Pass 0.7737 2956 2182 73 Pass 0.7887 2791 1988 71 Pass 0.8038 2603 1802 69 Pass 0.8188 2451 1634 66 Pass 0.8339 2312 1458 63 Pass 0.8489 2165 1282 59 Pass 0.8640 2033 1155 56 Pass 0.8790 1898 1031 54 Pass 0.8941 1790 912 50 Pass 0.9091 1688 820 48 Pass 0.9242 1586 742 46 Pass 0.9392 1483 652 43 Pass 0.9543 1381 583 42 Pass 0.9693 1293 540 41 Pass 0.9844 1222 500 40 Pass 0.9994 1155 459 39 Pass 1.0145 1098 425 38 Pass 1.0295 1049 392 37 Pass 1.0446 997 364 36 Pass 1.0596 930 337 36 Pass 1.0747 884 318 35 Pass 1.0897 839 296 35 Pass 1.1048 790 268 33 Pass 1.1198 744 240 32 Pass 1.1349 718 217 30 Pass 1.1499 673 197 29 Pass 1.1650 634 177 27 Pass Woodbridge Bldg B 1/26/2021 4:10:30 PM Page 27 1.1800 595 160 26 Pass 1.1951 565 148 26 Pass 1.2101 539 138 25 Pass 1.2252 497 129 25 Pass 1.2402 473 125 26 Pass 1.2553 434 117 26 Pass 1.2703 400 113 28 Pass 1.2854 368 101 27 Pass 1.3004 348 89 25 Pass 1.3155 323 84 26 Pass 1.3305 296 74 25 Pass 1.3456 273 67 24 Pass 1.3606 256 62 24 Pass 1.3757 235 59 25 Pass 1.3907 217 56 25 Pass 1.4058 198 54 27 Pass 1.4208 181 50 27 Pass 1.4359 158 48 30 Pass 1.4509 145 44 30 Pass 1.4660 130 43 33 Pass 1.4810 119 41 34 Pass 1.4961 109 40 36 Pass 1.5111 97 39 40 Pass 1.5262 91 36 39 Pass 1.5412 82 29 35 Pass 1.5563 76 25 32 Pass 1.5713 69 21 30 Pass 1.5864 61 21 34 Pass 1.6014 54 20 37 Pass 1.6165 48 18 37 Pass 1.6315 41 17 41 Pass 1.6466 38 15 39 Pass 1.6616 33 12 36 Pass 1.6767 27 12 44 Pass 1.6917 22 11 50 Pass 1.7068 21 11 52 Pass 1.7218 20 10 50 Pass 1.7369 19 7 36 Pass 1.7519 17 7 41 Pass 1.7670 14 6 42 Pass 1.7820 12 5 41 Pass 1.7971 8 4 50 Pass 1.8121 4 2 50 Pass 1.8272 3 1 33 Pass 1.8422 3 0 0 Pass 1.8573 3 0 0 Pass 1.8723 3 0 0 Pass Woodbridge Bldg B 1/26/2021 4:10:30 PM Page 28 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 B 1/26/2021 4:10:33 PM Page 30 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area:0 Total Impervious Area:4.21 Mitigated Landuse Totals for POC #2 Total Pervious Area:0 Total Impervious Area:4.21 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 1.605124 5 year 2.027457 10 year 2.314404 25 year 2.686615 50 year 2.971496 100 year 3.263295 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 1.605124 5 year 2.027457 10 year 2.314404 25 year 2.686615 50 year 2.971496 100 year 3.263295 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 2.079 2.079 1950 2.246 2.246 1951 1.299 1.299 1952 1.155 1.155 1953 1.247 1.247 1954 1.305 1.305 1955 1.480 1.480 1956 1.456 1.456 1957 1.652 1.652 1958 1.333 1.333 1959 1.360 1.360 Woodbridge Bldg B 1/26/2021 4:11:01 PM Page 36 Water Quality Water Quality BMP Flow and Volume for POC #2 On-line facility volume:0.5174 acre-feet On-line facility target flow:0.684 cfs. Adjusted for 15 min:0.684 cfs. Off-line facility target flow:0.3865 cfs. Adjusted for 15 min:0.3865 cfs. Woodbridge Bldg B 1/26/2021 4:11:01 PM Page 38 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 B 1/26/2021 4:11:32 PM Page 47 POC 5 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #5 Total Pervious Area:2.91 Total Impervious Area:9.16 Mitigated Landuse Totals for POC #5 Total Pervious Area:2.91 Total Impervious Area:9.16 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #5 Return Period Flow(cfs) 2 year 3.678223 5 year 4.713899 10 year 5.42547 25 year 6.356605 50 year 7.074777 100 year 7.814838 Flow Frequency Return Periods for Mitigated. POC #5 Return Period Flow(cfs) 2 year 3.678223 5 year 4.713899 10 year 5.42547 25 year 6.356605 50 year 7.074776 100 year 7.814837 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #5 Year Predeveloped Mitigated 1949 4.945 4.945 1950 4.955 4.955 1951 3.080 3.080 1952 2.546 2.546 1953 2.751 2.751 1954 2.997 2.997 1955 3.353 3.353 1956 3.312 3.312 1957 3.872 3.872 1958 3.004 3.004 1959 2.960 2.960 Woodbridge Bldg B 1/26/2021 4:12:03 PM Page 56 Appendix Predeveloped Schematic Woodbridge Bldg B 1/26/2021 4:12:03 PM Page 57 Mitigated Schematic Woodbridge Bldg B 1/26/2021 4:12:04 PM Page 74 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. 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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 Revised Geotechnical Engineering Services Report Proposed Greenline Building B Development Federal Way, Washington for Federal Way Campus, LLC June 21, 2018 Revised Geotechnical Engineering Services Report Proposed Greenline Building B Development Federal Way, Washington for Federal Way Campus, LLC June 21, 2018 1101 South Fawcett Avenue, Suite 200 Tacoma, Washington 98402 253.383.4940 June 21, 2018| Page i File No. 22247-001-03 Table of Contents INTRODUCTION ......................................................................................................................................................... 1 PROJECT DESCRIPTION ........................................................................................................................................... 1 SCOPE OF SERVICES ............................................................................................................................................... 2 SITE CONDITIONS ..................................................................................................................................................... 3 Surface Conditions............................................................................................................................................... 3 Mapped Geologic Conditions .............................................................................................................................. 3 Subsurface Conditions ........................................................................................................................................ 4 Groundwater ........................................................................................................................................................ 4 CONCLUSIONS AND RECOMMENDATIONS ............................................................................................................ 5 General ................................................................................................................................................................. 5 Site Development and Earthwork ....................................................................................................................... 5 General .......................................................................................................................................................... 5 Stripping and Clearing .................................................................................................................................. 6 Subgrade Evaluation ..................................................................................................................................... 6 Excavation ..................................................................................................................................................... 6 Excavation Support ....................................................................................................................................... 7 Wet Weather Recommendations ................................................................................................................. 7 Fill Materials ......................................................................................................................................................... 8 On-site Soils ................................................................................................................................................... 9 Select Granular Fill ........................................................................................................................................ 9 Pipe Bedding ................................................................................................................................................. 9 Crushed Rock ................................................................................................................................................ 9 Fill Placement and Compaction .......................................................................................................................... 9 General .......................................................................................................................................................... 9 Area Fills and Bases ................................................................................................................................... 10 Building Pad Subgrade .............................................................................................................................. 10 Trench Backfill ............................................................................................................................................ 10 Temporary and Permanent Slopes .................................................................................................................. 11 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 .............................................................................................................................. 13 Lateral Resistance ..................................................................................................................................... 13 Building Pad and Floor Slabs .................................................................................................................... 13 Retaining Structures ......................................................................................................................................... 14 Pavement Recommendations .......................................................................................................................... 14 Pavement Design ....................................................................................................................................... 14 Stormwater Infiltration Evaluation ................................................................................................................... 15 June 21, 2018| Page ii File No. 22247-001-03 LIMITATIONS .......................................................................................................................................................... 16 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-17 – Logs of Explorations Figures A-18 through A-20 – Sieve Analysis Results Appendix B. Field Explorations and Laboratory Testing-2016 Appendix C. Report Limitations and Guidelines for Use June 21, 2018| Page 1 File No. 22247-001-03 INTRODUCTION This revised report presents the results of our geotechnical engineering services for the Proposed Greenline Building B Development on a portion of the former Weyerhaeuser Campus Property in Federal Way, Washington. Figure 1 shows the site location. Figure 2 shows the approximate current layout of the site. We completed a geotechnical report for this project on August 16, 2017. We understand the site layout and proposed site grades have been changed since our previous report. Our report has also been revised to address comments by the City of Federal Way. The parcel is presently forested and mostly undeveloped. The site contains a relatively flat plateau in the west that generally slopes slightly downward to the south. The east margin of the plateau slopes downward to the east, to relatively flat to undulatory ground in the east part of the site. North-south oriented asphalt/ gravel-covered driveways are located in the east and west parts of the site. We understand that these features were access roads to a residential development that occupied portions of the site and ground to the north until about 1978. East-west oriented gravel-covered trails also exist at the site. These features are shown in 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 site plan provided to us on June 20, 2018. This information included the proposed grading plan. Proposed Building “B” will be located just south of proposed Building “A”. The northwest corner of proposed Building “B” is within the former Victory Unlimited, 19-acre parcel. We prepared a geotechnical design report for the proposed Victory development dated June 17, 2016. We also prepared a geotechnical design report for the Building “A” site on March 9, 2017. We understand that the currently proposed Greenline Building “B” Development will comprise a one-story (45-foot-high) 214,050-square-foot building with asphalt concrete (AC) pavement and Portland cement concrete (PCC) pavement in parking and access areas. Parking for up to 245 vehicles is planned for the development. A stormwater detention pond is planned for the south part of the site. The finish floor elevation for the structure is planned to range from Elevation 393 feet in the southeast to 396.4 feet in the northwest. Cuts and fills will be required to create the building pad. Soil cuts are planned through most of the building pad area and appear typically less than 5 feet. One exception is in the northwest corner where cuts up to about 12 feet will be required in the proposed parking area. The greatest fill thickness (approximately 7 feet) is required in the southeast corner of the building footprint. We understand that a 2H:1V (horizontal:vertical) cut slope will be used to establish planned grade along the northwest site boundary. A 6- to 13-foot high retaining wall is planned for the east and southeast margin of the site. We understand that the wall type has not been determined. The proposed Greenline Building B project layout is shown in Figure 3. June 21, 2018| Page 2 File No. 22247-001-03 SCOPE OF SERVICES The purpose of our services for this study is to review our previous studies, supplement the existing subsurface information with additional explorations, and prepare a geotechnical report specific to the proposed Greenline Building “B” development. Our services have been provided in general accordance with the confirming agreement dated June 29, 2017. Specifically, GeoEngineers scope includes: 1. Reviewing preliminary Greenline Building B project plans provided by the design team. This drawing was provided by ESM on June 22, 2017. Reviewing site plan and grading plan documents provided by ESM on June 20, 2018. 2. Reviewing published geologic maps and historical aerial photographs for the site. The aerial photographs are dated the following years: 1943, 1956, 1965, 1968, 1972, 1978, 1980, 1986, 1990, 1991, 2005, 2006, 2009 and 2011. 3. Comparing the project plans with the previously completed explorations. 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. Developing a subsurface exploration plan to supplement the previously completed explorations. The supplemental plan included thirteen test pit explorations and three borings. 6. Performing a brief geologic reconnaissance to evaluate current (August 2017) surface conditions at accessible portions of the site. 7. Performing geotechnical laboratory tests on representative samples obtained from the explorations. Tests included moisture content determinations and particle size analyses. 8. Describing site conditions based on our site observations, review of published maps/aerial photographs and laboratory test results, and subsurface soil and groundwater conditions encountered in the borings and test pits. 9. 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. 10. Providing recommendations for temporary and permanent slopes. 11. Providing recommendations for shallow foundation support, including footing size, allowable soil bearing pressure and estimated post-construction settlements. We have assumed typical foundation and slab loads for the proposed structure. 12. Discussing footing construction considerations including excavation, bearing surface preparation, material requirements and compaction requirements. 13. Providing subgrade preparation recommendations and modulus of subgrade reaction for design of slabs-on-grade. 14. Evaluating lateral earth pressures for design of below-grade structures, such as, dock-high walls. June 21, 2018| Page 3 File No. 22247-001-03 15. 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. 16. Providing recommendations for pavement subgrade preparation and AC pavement design sections for both automobile and truck traffic areas. 17. Discussing drainage considerations for construction based on the conditions encountered in our explorations. 18. 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. SITE CONDITIONS Surface Conditions The site occupies two relatively level areas, which are separated by a slope that descends downward to the southeast and east. Existing ground surface ranges from about Elevation 408 feet in the northwest to about Elevation 380 feet in the east. 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. Conifer trees predominate in the central, south and west parts of the site. Deciduous trees are more prevalent in the east part of the site. The site appeared thickly vegetated in all but one of the historical aerial photographs reviewed. The southwest part of the site appeared partially cleared of trees in the 1943 photograph. Trees were re- established in this are in the 1956 photograph. Isolated small wetland areas are mapped in the east and south portions of the site 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 August site visits. Some surface water was observed in similar areas just north of the Greenline “B” site in March 2017. We observed some dark, organic-rich soils exposed at the ground surface within the wetland and drainage areas at the time of our site visits. Former residential street access roads were observed at the site, shown as north-south trails in Figure 2. The roadways appeared to be surfaced in gravel, however, it also appeared that AC pavement underlies the gravel in some places. The access roads were visible in all aerial photographs reviewed. A residential development occupied the property just north of the Greenline “B” site 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- June 21, 2018| Page 4 File No. 22247-001-03 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 Thirteen test pits and three borings were completed at the site on July 18 and 24, 2017. These explorations are supplemental to our May 2016 explorations completed as part of our study for the neighboring Victory development concept. Details of the field exploration and laboratory testing programs completed for the current development study are summarized in Appendix A. The exploration logs and results of the laboratory testing program are also presented in Appendix A. Exploration logs and laboratory testing results completed in 2016 are contained in Appendix B. The approximate location of all the explorations are shown in Figures 2 and 3. Relatively thin layers of fill were encountered in previously completed test pit TP-2 and boring B-5. The fill in these explorations extended to about 2 feet below ground surface (bgs) and appeared to comprise re- worked native materials. A greater fill thickness (potentially 11 feet) was encountered in recently completed boring B-1. The fill comprised medium dense to dense silty sand with gravel, and may have been placed to construct the eastern-most trail/access road. Varying thicknesses of forest duff and/or topsoil and sod were encountered from the ground surface in the other explorations. The organic material/duff layer ranged from about 6 inches to about 2 feet thick in the explorations, and appeared to average about 1 to 1.5 feet in thickness. 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 most of the explorations. The unweathered glacial till, where present, was encountered to depths ranging from about 2.5 feet to about 10 feet 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 8 to 87 percent. In-place moisture contents ranged from 6 to 35 percent. Groundwater Groundwater was not observed in any of the recently completed explorations for the Building “B” project. Groundwater was encountered in the following explorations completed for the former Victory development. Borings 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 during the wetter winter and early spring months. June 21, 2018| Page 5 File No. 22247-001-03 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 building 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, we recommend that earthwork be performed during the normally drier periods of the year. Moisture conditioning of site soils will likely be necessary in order to obtain the required compaction. ■ We anticipate that the native soils 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. ■ 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 sensitivity of most 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 building 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 an allowable soil bearing pressure of 4,000 pounds per square foot (psf) for design of shallow footings. A higher bearing pressure can be achieved on the undisturbed glacial till at depth, if necessary. We can provide additional recommendations during final design of the building, if needed. ■ Floor slabs may be supported on-grade following subgrade preparation as recommended in this report. 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 that is a coarse-grained aggregate with negligible sand and silt that meets the criteria contained in American Association of State Highway and Transportation Officials (AASHTO) Grading #67. 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 and north parts 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 June 21, 2018| Page 6 File No. 22247-001-03 export of unsuitable wet on-site soil and import of select granular soil if earthwork will be performed during periods of wet weather. The following sections provide our recommendations for earthwork, site development, and fill materials. Stripping and Clearing The existing trees, shrubs, topsoil, and unsuitable 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 12 and 24 inches. Greater stripping depths will be required to remove localized zones of loose or organic-rich soil and tree roots. Greater stripping depths may also be required in wetland areas. The primary root 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 organic-rich native soils should be expected in wetland areas. These soils may contain a high percentage of organic materials and must be removed where present in areas of proposed pavements or structures. Asphalt concrete within existing trail areas should be removed or pulverized and used in fills at the direction of the geotechnical engineer. 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 June 21, 2018| Page 7 File No. 22247-001-03 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 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. June 21, 2018| Page 8 File No. 22247-001-03 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. ■ 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. June 21, 2018| Page 9 File No. 22247-001-03 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. Pipe Bedding Trench backfill for the bedding and pipe zone must consist of well-graded granular material with a maximum particle size of ¾ 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. 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. June 21, 2018| Page 10 File No. 22247-001-03 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). In pavement areas, the compaction criteria can be reduced to 92 percent below a depth of 2 feet from finished grade. 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 the site grading plan, it appears that earth fills are to be placed on the eastern and northern portions of the site. Some of the east and southeast 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. If bench drains are required, they should be sloped to drain to a suitable discharge that does not result in erosion. Building Pad Subgrade Portions of the building pad will transition from cut to fill. In order to limit differential settlement to within ½ 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. June 21, 2018| Page 11 File No. 22247-001-03 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 1½H: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 in accordance with our previous benching recommendations. 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 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. We recommend a perimeter footing drain be constructed around the building footprint to capture the perched groundwater. 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 June 21, 2018| Page 12 File No. 22247-001-03 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, groundwater conditions, 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 the subsurface conditions encountered at this site, 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. Foundation Support Shallow Foundations The proposed 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 an 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 June 21, 2018| Page 13 File No. 22247-001-03 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 ¾ 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 ½ 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 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 150 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 ¾ inch for typical floor loading (approximately 300 psf). We estimate that differential settlement of the floor slabs, will be ½ 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 that meets the criteria for AASHTO Grading #67. 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. June 21, 2018| Page 14 File No. 22247-001-03 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 density 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 density 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. We recommend a rectangular pressure of 8H be utilized for seismic design. 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 from 8 to 10 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 30 degrees and a soil unit weight of 125pcf should be used in design. Higher strength values will result in excessive wall strain after construction. As discussed previously, all retaining walls should be constructed with a drainage layer and drain pipe behind the wall. We understand that rockery 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 June 21, 2018| Page 15 File No. 22247-001-03 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 ½ inch, PG 58-22 ■ 4 inches of crushed surfacing base course ■ 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 ½ 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 Soils encountered in the site area generally consists of weathered till over unweathered till. Grain-size distribution analyses of these soils indicate fines contents ranging between about 20 to about 60 percent. June 21, 2018| Page 16 File No. 22247-001-03 The unweathered till is typically in a dense condition and has very low permeability with respect to the vertical flow of water. Outwash and glacio-lacustrine soils appear to have been encountered in borings B-2, B-3 and in test pit TP-11. Grain-size distribution data indicate these soils have fine contents ranging from about 15 percent to 87 percent. These soils appear limited in extent at the site. 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 revised geotechnical report for use by Federal Way Campus LLC and their agents for the Proposed Greenline Building B 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. 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 C titled “Report Limitations and Guidelines for Use” for additional information pertaining to use of this report. µ SIT E Vicinity Map Figure 1 Proposed Greenline Building B DevelopmentFederal Way, Washington 2,000 2,0000 Feet Data Source : Mapbox Open Street Map, 2017 Notes:1. The lo cations of a ll feature s shown are approximate.2. This d rawing is for information purposes. It is intended to a ssist in showing features discussed in an attached document. G eoEngin eers, Inc. cannot guarantee the accuracy and content o f electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. Projection: NAD 198 3 StatePlane Washington North FIPS 4601 Feet P:\22\22247001\GIS\MXDs\2224700103_F01_VicinityMap.mxd Date Exported: 06/21/18 by cchelf WETLAND AA WETLAND DQ WETLAND EE WETLAND DR WETLAND DX WETLAND DZ WETLAND DW WETLAND DU WETLAND DP WETLAND DV WETLAND EB WETLAND DT WETLAND EC WETLAND EF WETLAND ED Loop Road Weyerhauser Way SWeyerhauser Way S Loop Road B-1 B-1Test Pit 12B-2 TP-3 TP-4 TP-1 TP-2 TP-5 TP-6 TP-9 TP-8 TP-10 TP-13 TP-12 TP-7 TP-11 B-5 TP-1 B-4 B-3 B-1 B-6 B-2 TP-2 TP-3 TP-8 TP-7 TP-6 TP-5 TP-4 TP-13 TP-11 TP-10 TP-9 TP-12 18 Trail Trail Trail Trail Trail B-3 Trail Existing Steep Cut Slope Proposed Greenline Building "B" Site Driveway DrivewayFigure 2 Proposed Greenline Building B Development Federal Way, Washington Site Plan Existing ConditionsW ENSFeet 0150 150 P:\22\22247001\CAD\03\GeoTech\2224700103_F02_Site Plan Existing.dwg TAB:F02 Date Exported: 06/21/18 - 9:58 by lkillgoreLegend Boring by GeoEngineers, 2017 Test Pit by GeoEngineers, 2017TP-1 B-1 Boring by GeoEngineers, 2016 Test Pit by GeoEngineers, 2016 B-1 TP-1 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, on 06/20/2018. Wetlands by others. Projection: WA State Plane, North Zone, NAD83, US Foot WETLAND AA WETLAND DQ WETLAND EE WETLAND DR WETLAND DX WETLAND DZ WETLAND DW WETLAND DU WETLAND DP WETLAND DV WETLAND EB WETLAND DT WETLAND EC WETLAND EF WETLAND ED Loop Road Weyerhauser Way SWeyerhauser Way S B-1Test Pit 1218 Trail Trail Trail Loop Road Proposed Retaining Wall Location Existing Steep Cut Slope Proposed Stormwater Detention Ponds B-1 B-2 TP-3 TP-4 TP-1 TP-2 TP-5 TP-6 TP-9 TP-8 TP-10 TP-13 TP-12 TP-7 TP-11 B-5 TP-1 B-4 B-3 B-1 B-6 B-2 TP-2 TP-3 TP-8 TP-7 TP-6 TP-5 TP-4 TP-13 TP-11 TP-10 TP-9 TP-12 B-3 Proposed Greenline Building "B" Site Trail Trail Figure 3 Proposed Greenline Building B Development Federal Way, Washington Site Plan Proposed ConditionW ENSFeet 0150 150 P:\22\22247001\CAD\03\GeoTech\2224700103_F03_Site Plan Proposed.dwg TAB:F03 Date Exported: 06/21/18 - 9:58 by lkillgoreLegend Boring by GeoEngineers, 2017 Test Pit by GeoEngineers, 2017 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 on 06/20/2018. Wetlands by others. Projection: WA State Plane, North Zone, NAD83, US Foot TP-1 B-1 Boring by GeoEngineers, 2016 Test Pit by GeoEngineers, 2016 B-1 TP-1 Site Boundary Bench DrainNot to ScaleNot to ScaleBackfill: Freedraining Sand and/or Rock. Minimum9-inch Enclosure of Pipe. Adjust Depth Based on SoilCondition Encountered and Seepage Observations.Native Soil BenchGround Surface6"Ø Pipe HDPE or PVC PerforatedVariable2'Final Fill Surface Profile8' MIN.KeywayConceptual Arrangement ofBench Cuts Into Native Soil.If Seepage EncounteredDuring Benching, PlaceDrain At This Location.Drain Detail is Shown Above.Native Building SubgradePre-development Ground SurfaceFill SoilNative SoilNotes:1. The locations of all features shown are approximate.2. This drawing is for information purposes. It is intended to assistin showing features discussed in an attached document.GeoEngineers, Inc. cannot guarantee the accuracy and contentof 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.P:\22\22247001\CAD\03\GeoTech\2224700103_F04_Schematic Drawing Hillside Fill.dwg TAB:F04 Date Exported: 06/21/18 - 11:57 by lkillgore Figure 4Schematic Drawing Hillside FillProposed Greenline Building B DevelopmentFederal Way, Washington APPENDIX A Field Explorations and Laboratory Testing June 21, 2018| Page A-1 File No. 22247-001-03 APPENDIX A FIELD EXPLORATIONS AND LABORATORY TESTING Field Explorations Subsurface conditions at the site were explored by drilling a total of 3 borings and excavating 13 test pits to supplement previous explorations completed at the site. The explorations were completed on July 18 and 24, 2017. Borings were drilled to depths of 16.5 to 21.5 feet. Test pits were excavated to depths ranging from 6 to 15 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-17 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-18 through A-20. Measured groundwater level in exploration, well, or piezometer Measured free product in well or piezometer Distinct contact between soil strata Approximate contact between soil strata Contact between geologic units SYMBOLS TYPICAL DESCRIPTIONS GW GP SW SP SM FINE GRAINED SOILS SILTS AND CLAYS NOTE: Multiple symbols are used to indicate borderline or dual soil classifications MORE THAN 50% RETAINED ON NO. 200 SIEVE MORE THAN 50% PASSING NO. 200 SIEVE GRAVEL AND GRAVELLY SOILS SC LIQUID LIMIT LESS THAN 50 (APPRECIABLE AMOUNT OF FINES) (APPRECIABLE AMOUNT OF FINES) COARSE GRAINED SOILS MAJOR DIVISIONS GRAPH LETTER GM GC ML CL OL SILTS AND CLAYS SANDS WITH FINES SAND AND SANDY SOILS MH CH OH PT (LITTLE OR NO FINES) CLEAN SANDS GRAVELS WITH FINES CLEAN GRAVELS (LITTLE OR NO FINES) WELL-GRADED GRAVELS, GRAVEL -SAND MIXTURES CLAYEY GRAVELS, GRAVEL - SAND -CLAY MIXTURES WELL-GRADED SANDS, GRAVELLYSANDS POORLY-GRADED SANDS, GRAVELLYSAND SILTY SANDS, SAND - SILT MIXTURES CLAYEY SANDS, SAND - CLAYMIXTURES INORGANIC SILTS, ROCK FLOUR,CLAYEY SILTS WITH SLIGHTPLASTICITY INORGANIC CLAYS OF LOW TOMEDIUM PLASTICITY, GRAVELLYCLAYS, SANDY CLAYS, SILTY CLAYS,LEAN CLAYS ORGANIC SILTS AND ORGANIC SILTYCLAYS OF LOW PLASTICITY INORGANIC SILTS, MICACEOUS ORDIATOMACEOUS SILTY SOILS INORGANIC CLAYS OF HIGHPLASTICITY ORGANIC CLAYS AND SILTS OFMEDIUM TO HIGH PLASTICITY PEAT, HUMUS, SWAMP SOILS WITHHIGH ORGANIC CONTENTSHIGHLY ORGANIC SOILS SOIL CLASSIFICATION CHART MORE THAN 50% OF COARSE FRACTION RETAINED ON NO. 4 SIEVE MORE THAN 50% OF COARSE FRACTION PASSING ON NO. 4 SIEVE SILTY GRAVELS, GRAVEL - SAND -SILT MIXTURES POORLY-GRADED GRAVELS,GRAVEL - SAND MIXTURES LIQUID LIMIT GREATER THAN 50 Continuous Coring Bulk or grab Direct-Push Piston Shelby tube Standard Penetration Test (SPT) 2.4-inch I.D. split barrel Contact between soil of the same geologic unit Material Description Contact Graphic Log Contact 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. Groundwater Contact 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. "P" indicates sampler pushed using the weight of the drill rig. "WOH" indicates sampler pushed using the weight of the hammer. Key to Exploration Logs Figure A-1 Sampler Symbol Descriptions ADDITIONAL MATERIAL SYMBOLS NS SS MS HS No Visible Sheen Slight Sheen Moderate Sheen Heavy Sheen Sheen Classification SYMBOLS Asphalt Concrete Cement Concrete Crushed Rock/ Quarry Spalls Topsoil GRAPH LETTER AC CC SOD Sod/Forest Duff CR DESCRIPTIONS TYPICAL TS Laboratory / Field Tests %F %G AL CA CP CS DD DS HA MC MD Mohs OC PM PI PP SA TX UC VS Percent fines Percent gravel Atterberg limits Chemical analysis Laboratory compaction test Consolidation test Dry density Direct shear Hydrometer analysis Moisture content Moisture content and dry density Mohs hardness scale Organic content Permeability or hydraulic conductivity Plasticity index Pocket penetrometer Sieve analysis Triaxial compression Unconfined compression Vane shear 33 45 10 16 Brown silty fine to medium sand with gravel (medium dense, moist) (fill?) Brown silty fine to medium sand with gravel (dense, wet) (weatherd till?) Mottled gray-brown silty fine to medium sand with gravel (very dense, moist) (till) 1 SA 2 3 SA 4 18 18 3 3 21 42 50/5" 50/3" SM SM SM Notes:Gravel road, dense brush and trees beyond road 7/24/2017 7/24/2017 18 CRG SWH Holocene Drilling, Inc.Hollow-stem Auger Diedrich D50Drilling EquipmentAutomatic 140 (lbs) / 30 (in) Drop WA State Plane North NAD83 (feet) 1278069 111175 377 NAVD88 Easting (X) Northing (Y) Surface Elevation (ft) Vertical Datum Drilled Start End Total Depth (ft) Logged By Checked By Hammer Data System Datum Driller Drilling Method Groundwater not observed at time of exploration Note: See Figure A-1 for explanation of symbols. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey. Sheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Boring B-1 Proposed Greenline Building B Development Figure A-2 Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_GEOTECH_STANDARD_%F_NO_GWFinesContent (%)MoistureContent (%)REMARKS FIELD DATA MATERIAL DESCRIPTION Sample NameTestingRecovered (in)IntervalBlows/footCollected SampleDepth (feet)0 5 10 15 Graphic LogGroupClassificationElevation (feet)375370365360 153 Density may be exaggerated due to gravel No recovery Brown silty fine to coarse gravel with sand (very dense, moist) (glacial till) Gray silty fine to medium sand with gravel (very dense, moist) (till) 1 2 SA 3 4 5 16 16 0 2 0 62 82 50/3" 50/2" 50/3" GM SM Notes: 7/24/2017 7/24/2017 16.5 CRG SWH Holocene Drilling, Inc.Hollow-stem Auger Diedrich D50Drilling EquipmentAutomatic 140 (lbs) / 30 (in) Drop WA State Plane North NAD83 (feet) 1278041 111330 379 NAVD88 Easting (X) Northing (Y) Surface Elevation (ft) Vertical Datum Drilled Start End Total Depth (ft) Logged By Checked By Hammer Data System Datum Driller Drilling Method Groundwater not observed at time of exploration Note: See Figure A-1 for explanation of symbols. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey. Sheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Boring B-2 Proposed Greenline Building B Development Figure A-3 Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_GEOTECH_STANDARD_%F_NO_GWFinesContent (%)MoistureContent (%)REMARKS FIELD DATA MATERIAL DESCRIPTION Sample NameTestingRecovered (in)IntervalBlows/footCollected SampleDepth (feet)0 5 10 15 Graphic LogGroupClassificationElevation (feet)375370365 26 47 20 15 17 8 Groundwater observed at 20 feet Brown silty fine to coarse sand with gravel (loose, moist) (fill?) Mottled gray/brown silty fine to medium sand with gravel (medium dense, moist) (weathered till) Brown silty fine to coarse gravel with sand (very dense, moist) (glacial till) Gray silty fine to medium sand with gravel (very dense, moist to wet) (glacial till) Grades to wet 1 SA 2 SA 3 SA 4 5 1 5 14 16 11 33 56 66/9" 76/9" SM SM GM SM Notes: 7/24/2017 7/24/2017 21 CRG SWH Holocene Drilling, Inc.Hollow-stem Auger Diedrich D50Drilling EquipmentAutomatic 140 (lbs) / 30 (in) Drop WA State Plane North NAD83 (feet) 1277716 110847 388 NAVD88 Easting (X) Northing (Y) Surface Elevation (ft) Vertical Datum Drilled Start End Total Depth (ft) Logged By Checked By Hammer Data System Datum Driller Drilling Method See "Remarks" section for groundwater observed Note: See Figure A-1 for explanation of symbols. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey. Sheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Boring B-3 Proposed Greenline Building B Development Figure A-4 Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_GEOTECH_STANDARD_%F_NO_GWFinesContent (%)MoistureContent (%)REMARKS FIELD DATA MATERIAL DESCRIPTION Sample NameTestingRecovered (in)IntervalBlows/footCollected SampleDepth (feet)0 5 10 15 20 Graphic LogGroupClassificationElevation (feet)385380375370 Forest duff and organic-rich brown sandy silt with occasional gravel (soft, moist) Brown sandy silt with gravel (stiff, dry) (weathered till) Gray silty fine to coarse sand with fine to coarse gravel (very dense, moist) (glacial till) ML ML SM 1 SA 2 3 12 57 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-1 Proposed Greenline Building B Development Figure A-5Elevation (feet)386385384383382381380379Depth (feet)1 2 3 4 5 6 7 8 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 8 387 NAVD88 1277518 110602 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating Forest duff Brown/tan silty fine to medium sand with fine to coarse gravel and occasional organic matter (dense, moist) (weathered till) Gray silty fine to medium sand with fine to coarse gravel (very dense, moist) (till) DUF SM SM 1 2 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-2 Proposed Greenline Building B Development Figure A-6Elevation (feet)383382381380379378377Depth (feet)1 2 3 4 5 6 7 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 7 384 NAVD88 1277506 110656 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating Forest duff Brown silty fine to coarse sand with fine to coarse gravel and occasional organic debris (roots) (dense, dry) (weathered till) Gray silty fine to coarse sand with fine to coarse gravel (very dense, moist) (till) DUF SM SM 1 2 3 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-3 Proposed Greenline Building B Development Figure A-7Elevation (feet)386385384383382381380379378Depth (feet)1 2 3 4 5 6 7 8 9 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 9 387 NAVD88 1277602 110598 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating Brown forest duff, sandy silt with organic debris and occasional gravel Brown/tan silty fine to medium sand with fine to coarse gravel with occasional organic matter (dense, moist) (weathered till) Gray silty gravel with sand (very dense, moist) (till) DUF SM GM 1 2 3 SA 9 31 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-4 Proposed Greenline Building B Development Figure A-8Elevation (feet)387386385384383382381Depth (feet)1 2 3 4 5 6 7 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 7 388 NAVD88 1277635 110688 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating Forest duff Brown silty fine to medium sand with fine gravel (dense, moist) (weathered till) Gray silty fine to medium sand with fine to coarse gravel (very dense, moist) (till) DUF SM SM 1 2 3 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-5 Proposed Greenline Building B Development Figure A-9Elevation (feet)393392391390389388Depth (feet)1 2 3 4 5 6 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 6 394 NAVD88 1277506 111001 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating Forest duff Brown silty fine to medium sand with gravel (dense, moist) (weathered till) Gray silty fine to medium sand with gravel (very dense, moist) (till) DUF SM SM 1 2 3 SA 7 26 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-6 Proposed Greenline Building B Development Figure A-10Elevation (feet)396395394393392391Depth (feet)1 2 3 4 5 6 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 6 397 NAVD88 1277534 111137 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating Forest duff Brown silty fine to medium sand with gravel (dense, moist) (weathered till) Silty fine to medium sand with fine to coarse gravel (very dense, moist) (till) DUF SM SM 1 2 SA 3 9 36 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-7 Proposed Greenline Building B Development Figure A-11Elevation (feet)402401400399398397396Depth (feet)1 2 3 4 5 6 7 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 7 403 NAVD88 1277613 111356 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating Forest duff, brown organic sandy silt with occasional gravel Brown-tan silty fine to medium sand with fine to coarse gravel (medium dense, moist) (weathered till) Gray silty fine to medium sand with fine to coarse gravel (very dense, moist) (till) DUF SM SM 1 2 3 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-8 Proposed Greenline Building B Development Figure A-12Elevation (feet)394393392391390389388387386Depth (feet)1 2 3 4 5 6 7 8 9 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 9 395 NAVD88 1277651 110984 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating Forest duff Brown silty fine to medium sand with fine to coarse gravel (dense, moist) (weathered till) Gray silty fine to medium sand with fine to coarse gravel (very dense, moist) (till) DUF SM SM 1 2 SA 3 13 41 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-9 Proposed Greenline Building B Development Figure A-13Elevation (feet)396395394393392391390Depth (feet)1 2 3 4 5 6 7 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 7.5 397 NAVD88 1277771 111152 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating Forest duff Brown mottled with tan silty fine sand with gravel (dense, moist) (weathered till) Gray silty fine to medium sand with fine to medium gravel (very dense, moist) (till) DUF SM SM 1 2 3 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-10 Proposed Greenline Building B Development Figure A-14Elevation (feet)392391390389388387386385Depth (feet)1 2 3 4 5 6 7 8 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 8 393 NAVD88 1277880 111331 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating Forest duff, brown organic-rich silt with occasional gravel Brown silty fine sand with organic debris with gravel (medium dense, moist) (recessional outwash?) Tan silt with fine sand with occasional gravel, rust mottled stains, cohesive (stiff, moist) (glacial till?) DUF SM ML 1 2 SA 3SA 14 35 38 87 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-11 Proposed Greenline Building B Development Figure A-15Elevation (feet)387386385384383382381380379378377376375374373Depth (feet)1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 15 388 NAVD88 1277708 110832 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating Forest duff Brown/tan silty fine to medium sand with gravel with occasional organic debris (dense, moist) (weathered till) Gray silty fine to medium sand with fine to coarse gravel (very dense, moist) (till) DUF SM SM 1 2 3 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-12 Proposed Greenline Building B Development Figure A-16Elevation (feet)387386385384383382381380Depth (feet)1 2 3 4 5 6 7 8 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 8 388 NAVD88 1277879 111014 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating Forest duff Brown/tan silty fine to medium sand with gravel (dense, moist) (weathered till) Gray silty fine sand with gravel (very dense, moist) (till) DUF SM SM 1 2 3 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 ½ foot. Coordinates Data Source: Horizontal approximated based on Topographic Survey. Vertical approximated based on Topographic Survey.Date:6/21/18 Path:P:\22\22247001\GINT\2224700103.GPJ DBLibrary/Library:GEOENGINEERS_DF_STD_US_JUNE_2017.GLB/GEI8_TESTPIT_1P_GEOTEC_%FSheet 1 of 1Project Number: Project Location: Project: Federal Way, Washington 22247-001-03 Log of Test Pit TP-13 Proposed Greenline Building B Development Figure A-17Elevation (feet)383382381380379378377376375Depth (feet)1 2 3 4 5 6 7 8 9 Testing SampleGraphic LogSAMPLE MATERIAL DESCRIPTION GroupClassificationSample NameTestingMoistureContent (%)REMARKS FinesContent (%)Date Excavated Surface Elevation (ft) Vertical Datum Coordinate System Horizontal Datum Easting (X) Northing (Y) Total Depth (ft)7/18/2017 9 384 NAVD88 1277920 110949 WA State Plane North NAD83 (feet) CRG Checked By SWH Groundwater not observed Caving not observedEquipment Trackhoe Logged By Excavator Kelly's Excavating 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 CLAYCOBBLES GRAVEL COARSE MEDIUM FINECOARSEFINE Exploration Number Depth (feet)Soil Description B-1 B-2 B-3 TP-1 2.5 5.5 13 3 Silty fine to medium sand with gravel (SM) Silty fine to coarse gravel with sand (GM) Silty fine to coarse gravel with sand (GM) Sandy silt with gravel (ML) Symbol Moisture (%) 10 3 8 12 3/8”3”1.5”#4 #10 #20 #40 #60 #1003/4”Figure A-18Sieve Analysis Results22247-001-03 Date Exported: 08/01/17 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 Greenline Building B DevelopmentFederal 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 CLAYCOBBLES GRAVEL COARSE MEDIUM FINECOARSEFINE Exploration Number Depth (feet)Soil Description TP-4 TP-6 TP-7 TP-9 6 5.5 3 2.5 Silty fine to coarse gravel with sand (GM) Silty fine sand with gravel (SM) Silty fine sand with gravel (SM) Silty fine sand with gravel (SM) Symbol Moisture (%) 9 7 9 13 3/8”3”1.5”#4 #10 #20 #40 #60 #1003/4”Figure A-19Sieve Analysis Results22247-002-00 Date Exported: 07/27/17 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 Greenline Building B DevelopmentFederal 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 CLAYCOBBLES GRAVEL COARSE MEDIUM FINECOARSEFINE Exploration Number Depth (feet)Soil Description TP-11 TP-11 3.5 8.5 Silty fine sand with gravel (SM) Silt with occasional sand (ML) Symbol Moisture (%) 14 35 3/8”3”1.5”#4 #10 #20 #40 #60 #1003/4”Figure A-20Sieve Analysis Results22247-001-03 Date Exported: 08/01/17 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 Greenline Building B DevelopmentFederal Way, Washington APPENDIX B Field Explorations and Laboratory Testing-2016 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 CLAYCOBBLES GRAVEL 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 CLAYCOBBLES GRAVEL 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 CLAYCOBBLES GRAVEL 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 CLAYCOBBLES GRAVEL 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 C Report Limitations and Guidelines for Use June 21, 2018| Page C-1 File No. 22247-001-03 APPENDIX C 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 Building B project specifically identified and described 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 June 29, 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 Building B 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. June 21, 2018| Page C-2 File No. 22247-001-03 ■ elevation, configuration, location, orientation or weight of the proposed structure; ■ composition of the design team; or ■ project ownership. If changes in the proposed layout and or design of the project 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. June 21, 2018| Page C-3 File No. 22247-001-03 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. June 21, 2018| Page C-4 File No. 22247-001-03 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.