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HomeMy WebLinkAboutTIR-3847-2015-09-17.pdf Te c h n i c a l I n f o r m a t i o n R e p o r t IK E A Re n t o n , W a s h i n g t o n Ou r J o b N o . 1 6 8 3 6 16836.006.doc TABLE OF CONTENTS 1.0 PROJECT OVERVIEW Figure 1 – Technical Information Report (TIR) Worksheet Figure 2 – Site Location Figure 3 – Drainage Basins, Subbasins, and Site Characteristics Figure 4 – Soils 2.0 CONDITIONS AND REQUIREMENTS SUMMARY 2.1 Analysis of the Core Requirements 2.2 Analysis of the Special Requirements 3.0 OFF-SITE ANALYSIS 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN A. Existing Site Hydrology B. Developed Site Hydrology C. Performance Standards D. Flow Control System E. Water Quality System 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN 6.0 SPECIAL REPORTS AND STUDIES 7.0 OTHER PERMITS 8.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN ANALYSIS AND DESIGN A. Erosion and Sediment Control (ESC) Plan Analysis and Design 9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 10.0 OPERATIONS AND MAINTENANCE MANUAL Tab 1.0 16836.006.doc 1.0 PROJECT OVERVIEW The proposed project consists of demolishing an existing IKEA store and parking structure, and constructing a new store and parking lot. The project is 29.00 acres in size, containing two tax parcels (362304-9113 and 312305-9169). The site is located at the intersection of S.W. 43rd Street and Lind Avenue S.W., in a portion of Sections 31 and 36, Township 23 North, Range 4 East, Willamette Meridian, in the City of Renton. The site is rectangular in shape and fronts S.W. 41st Street, Lind Avenue S.W., and S.W. 43rd Street. The site is currently developed with an IKEA store and a parking structure. The existing on-site improvements consist of storm, sewer, and water utilities, dry utilities including gas, power and telephone, landscaping, and paved parking areas. The site is bound along the east property line by an existing warehouse. The site is bound by Lind Avenue S.W. to the west, S.W. 41st Street to the north and S.W. 43rd Street to the south. The site will have access to the streets that bound it to the north, west, and south, which will require frontage improvements, including new sidewalk and planter strip. On-site soils are mapped as Woodinville silt loam and Snohomish silt loam. Please refer to the Soils Map in this section. All drainage calculations were modeled as till soils. The project will be constructing a new IKEA store, parking lot, planter areas, and frontage improvements including sidewalks and planter strips. The topography on site is generally flat, with minor relief, in order to drain areas to catch basins surrounding two existing large buildings serving as the IKEA store at this time. The drainage facilities are required to meet the requirements of the 2009 King County Surface Water Design Manual (KCSWDM), and the 2010 City of Renton Amendments to the KCSWDM. The drainage design shall meet, at a minimum, Peak Rate Flow Control Standard and Enhanced Basic Water Quality Treatment. The wetpond and wetvault will be sized pursuant to the 2009 KCSWDM and its amendments to ensure that the Water Quality requirement is met. Please refer to Section 4.0 for detailed drainage calculations. KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/1/09 1 16836.013.doc Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner IKEA North America Services Phone Address 420 Alan Wood Road Conshohocken, PA 19428 Project Engineer Chris Jensen, P.E. Company Barghausen Consulting Engineers , Inc. Phone (425) 251-6222 Project Name IKEA DDES Permit # Location Township 23 North Range 4 East Sections 31 and 36 Site Address S.W. 43rd Street & Lind Avenue S.W Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS Landuse Services Subdivision / Short Subd. / UPD Building Services M/F / Commercial / SFR Clearing and Grading Right-of-Way Use Other DFW HPA COE 404 DOE Dam Safety FEMA Floodplain COE Wetlands Other Shoreline Management Structural Rockery/Vault/ ESA Section 7 Part 5 PLAN AND REPORT INFORMATION Technical Information Report Type of Drainage Review Full / Targeted / (circle): Large Site Date (include revision 7/2/2014 dates): Date of Final: Site Improvement Plan (Engr. Plans) Type (circle one): Full / Modified / Small Site Date (include revision dates): Date of Final: Part 6 ADJUSTMENT APPROVALS Type (circle one): Standard / Complex / Preapplication / Experimental / Blanket Description: (include conditions in TIR Section 2) Date of Approval: KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/1/09 2 16836.013.doc Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: Completion Date: Describe: Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan : Special District Overlays: Drainage Basin: Black River Basin Stormwater Requirements: Basic Water Quality Part 9 ONSITE AND ADJACENT SENSITIVE AREAS River/Stream Lake Wetlands Closed Depression Floodplain Other Steep Slope Erosion Hazard Landslide Hazard Coal Mine Hazard Seismic Hazard Habitat Protection Part 10 SOILS Soil Type Slopes Erosion Potential Snohomish silt loam Woodinville silt loam High Groundwater Table (within 5 feet) Sole Source Aquifer Other Seeps/Springs Additional Sheets Attached KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/1/09 3 16836.013.doc Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE LIMITATION / SITE CONSTRAINT Core 2 – Offsite Analysis Sensitive/Critical Areas SEPA Other Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) West Threshold Discharge Area Core Requirements (all 8 apply) Discharge at Natural Location Number of Natural Discharge Locations: 2 Offsite Analysis Level: 1 / 2 / 3 dated: 6/6/14 Flow Control Level: 1 / 2 / 3 or Exemption Number 2 (incl. facility summary sheet) Small Site BMPs Rain Gardens Conveyance System Spill containment located at: Erosion and Sediment Control ESC Site Supervisor: Contact Phone: After Hours Phone: Maintenance and Operation Responsibility: Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Provided: Yes / No Liability Water Quality Type: Basic / Sens. Lake / Enhanced Basic / Bog (include facility summary sheet) or Exemption No. Meets Exemptions to Allow Basic Landscape Management Plan: Yes / No Special Requirements (as applicable) Area Specific Drainage Type: CDA / SDO / MDP / BP / LMP / Shared Fac. / None Requirements Name: Floodplain/Floodway Delineation Type: Major / Minor / Exemption / None 100-year Base Blood Elevation (or range): 21.5 Datum: NAVD88 Flood Protection Facilities Describe: N/A Source Control Describe landuse: (comm./industrial landuse) Describe any structural controls: KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/1/09 4 16836.013.doc Oil Control High-use Site: Yes / No Treatment BMP: Maintenance Agreement: Yes / No with whom? Other Drainage Structures Describe: Part 12.1 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) East Threshold Discharge Area Core Requirements (all 8 apply) Discharge at Natural Location Number of Natural Discharge Locations: 1 Offsite Analysis Level: 1 / 2 / 3 dated: 6/6/14 Flow Control Level: 1 / 2 / 3 or Exemption Number 2 (incl. facility summary sheet) Small Site BMPs Rain Garden Conveyance System Spill containment located at: Erosion and Sediment Control ESC Site Supervisor: TBD Contact Phone: After Hours Phone: Maintenance and Operation Responsibility: Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Provided: Yes / No Liability Water Quality Type: Basic / Sens. Lake / Enhanced Basicm / Bog (include facility summary sheet) or Exemption No. Landscape Management Plan: Yes / No Special Requirements (as applicable) Area Specific Drainage Type: CDA / SDO / MDP / BP / LMP / Shared Fac. / None Requirements Name: Floodplain/Floodway Delineation Type: Major / Minor / Exemption / None 100-year Base Blood Elevation (or range): 21.5 Datum: NAVD88 Flood Protection Facilities Describe: N/A Source Control Describe landuse: (comm./industrial landuse) Describe any structural controls: Oil Control High-use Site: Yes / No Treatment BMP: Maintenance Agreement: Yes / No with whom? Other Drainage Structures KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/1/09 5 16836.013.doc Describe: Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION Clearing Limits Cover Measures Perimeter Protection Traffic Area Stabilization Sediment Retention Surface Water Control Dewatering Control Dust Control Flow Control MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION Stabilize Exposed Surfaces Remove and Restore Temporary ESC Facilities Clean and Remove All Silt and Debris Ensure Operation of Permanent Facilities Flag Limits of SAO and open space preservation areas Other Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Type/Description Water Quality Type/Description Detention Infiltration Regional Facility Shared Facility Flow Control BMPs Other Biofiltration Wetpool Media Filtration Oil Control Spill Control Flow Control BMPs Other Wetpond and Wetvault Filterra Unit Rain Garden KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/1/09 6 16836.013.doc Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS Drainage Easement Covenant Native Growth Protection Covenant Tract Other Cast in Place Vault Retaining Wall Rockery > 4' High Structural on Steep Slope Other Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. June 11, 2015 Signed/Date b a rg h au s e n C O N S U L TINGENGINE E R S ,I N C . Horizontal: Scale: Vertical: For: Title: VICINITY MAP Job Number 18215 72ND AVENUE SOUTH KENT, WA 98032 (425) 251-6222 (425) 251-8782 CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES N.T.S.N/A 16836 DATE: 06/11/14 IKEA RENTON, WASHINGTON P:\16000s\16836\exhibit\graphics\16836 vmap.cdr REFERENCE: Rand McNally (2014) SITE b a rg h au s e n C O N S U L TINGENGINE E R S ,I N C . Horizontal: Scale: Vertical: For: Title: SOIL SURVEY MAP Job Number 18215 72ND AVENUE SOUTH KENT, WA 98032 (425) 251-6222 (425) 251-8782 CIVIL ENGINEERING, LAND PLANNING, SURVEYING, ENVIRONMENTAL SERVICES N.T.S.N/A 16836 DATE: 06/11/14 IKEA RENTON, WASHINGTON P:\16000s\16836\exhibit\graphics\16836 soil.cdr REFERENCE: USDA, Natural Resources Conservation Service LEGEND: Wo = Woodinville silt loam SITE So = Snohomish silt loam Tab 2.0 16836.006.doc 2.0 CONDITIONS AND REQUIREMENTS SUMMARY 2.1 Analysis of the Core Requirements Core Requirement No. 1: Discharge at the Natural Location. Response: The existing site has three natural discharge locations: one near the northeast corner of the site, one at the northwest corner of the site, and one at the southwest corner of the site. All of these discharge locations will be preserved in the developed condition. Core Requirement No. 2: Off-Site Analysis. Response: A Level 1 Off-Site Analysis was performed pursuant to the 2009 KCSWDM. See Section 3.0 for the Level 1 Off-Site Analysis. Core Requirement No. 3: Flow Control. Response: Per the City of Renton Flow Control Application Map, the project is subject to Peak Rate Flow Control Standard, in which the project must match developed peak discharge rates to the existing site conditions for the 2-, 10-, and 100-year return periods. See Section 4.0 for more information. However, since there will be less impervious area in the proposed condition than there was in the existing condition, flow control will not be needed, as the peak flows from the existing site are larger than the peak flow of the proposed site. Core Requirement No. 4: Conveyance System. Response: The conveyance system has been designed pursuant to the 2009 KCSWDM and the 2010 City of Renton Amendments to the KCSWDM. Conveyance calculations are included in Section 5.0. Core Requirement No. 5: Erosion and Sediment Control. Response: Temporary erosion and sediment control measures have been implemented pursuant to the 2009 KCSWDM and the 2010 City of Renton Amendments to the KCSWDM. See Section 8.0 for more information. Core Requirement No. 6: Maintenance and Operations. Response: Maintenance and Operations manuals for the proposed private storm are included in Section 10.0. Core Requirement No. 7: Financial Guarantees and Liability. Response: The project will provide a Site Improvement Bond Quantity Worksheet to establish a bond amount for a drainage facility restoration and site stabilization financial guarantee prior to construction. Core Requirement No. 8: Water Quality. Response: Per the 2010 City of Renton Amendments to the KCSWDM, the project is subject to Enhanced Basic Water Quality. However, the project is proposing to reduce the water quality requirement to Basic Water Quality by recording a covenant against title that states that no leachable metals will be proposed in areas of the site exposed to 16836.006.doc weather. A wetpond, wetvault, and a Filterra unit will be used to provide Basic Water Quality. See Section 4.0 for more information. 2.2 Analysis of the Special Requirements Special Requirement No. 1: Other Adopted Area-Specific Requirements. Response: The proposed project is not located in a designated Critical Drainage Area. Special Requirement No. 2: Flood Hazard Area Delineation. Response: As indicated by the FEMA Map included in this report, the proposed site does not lie within a floodplain or floodway of a stream. However, the actual surveyed conditions reveal portions of the site are below the 100-year base flood elevation. Therefore, the 100-year floodplain boundaries are delineated on the site improvement plans and proper compensatory storage has been provided. See Section 4.0 for more information. Special Requirement No. 3: Flood Protection Facilities. Response: The proposed project does not rely on an existing flood protection facility, nor does it propose to modify or construct a new flood protection facility. Therefore, this special requirement does not apply. Special Requirement No. 4: Source Control. Response: Since the project requires a commercial building permit, source control is required. Source control measures will be selected pursuant to the 2009 KCSWDM and the 2010 City of Renton Amendments to the KCSWDM. Special Requirement No. 5: Oil Control. Response: The site is not classified as a High Use Site given the criteria in the 2009 KCSWDM, so this special requirement does not apply, and therefore, no oil control is necessary. Tab 3.0 16836.006.doc 3.0 OFF-SITE ANALYSIS The Level 1 Downstream Analysis is provided in this section. Tab 4.0 16836.006.doc 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN A. Existing Site Hydrology The site is currently developed, with two warehouses on two tax parcels (362304-9113 and 312305-9169) and is currently zoned IM. The site fronts S.W. 41st Street, Lind Avenue S.W., and S.W. 43rd Street. The existing on-site improvements consist of storm, sewer, and water utilities, dry utilities including gas, power and telephone, landscaping, and paved parking areas. As indicated by the FEMA Map included in this report, the proposed site does not lie within a formally delineated floodplain or floodway of a stream. However, the actual surveyed conditions reveal portions of the site are below the 100-year base flood elevation. Compensatory storage will be used to mitigate proposed fill within the flood plain (elevation 21.5) equaling, at a minimum, the volume of fill within the flood plain. See the Proposed Flood Hazard Map in this section. Flood Elevations Certificates will be submitted prior to building finished floor construction. There are three separate drainage basins and two Threshold Discharge Areas (TDA) located on site, each with their own discharge location. Two of the basins (same TDA) are on the western third side of the site; the other is the remainder of the eastern portion of the site. The two basins along the west side of the site discharge at separate locations, but converge within ¼ mile downstream of the site, before discharging into Spring Brook Creek. The east basin discharges from the northeast corner of the site, and enters Spring Brook Creek approximately 1 mile downstream of the site. Therefore, there are two separate threshold discharge areas on site. The existing site contains 26.97 acres of impervious area, of which 17.48 acres is roof area, with the remaining area consisting of asphalt pavement, sidewalks and curb and gutter. B. Developed Site Hydrology The complete project will contain a new IKEA store and new paved parking areas with planters. The total developed area will be 29.00 acres in size. New impervious surfaces will include parking areas, roof, and sidewalks. The project will be providing landscaped pervious areas, such as planters, around the building and throughout the parking areas. The proposed site will contain 24.25 acres of impervious area and 3.91 acres of pervious surfaces. Since the proposed site will have less impervious area than the existing site, flow control will not be required to match peaks from the existing condition. See Part D in this section for more information. Since the project proposes to fill within an existing floodplain, compensatory storage will be provided to mitigate the fill within the floodplain. Only the portion of cut below the floodplain that can freely drain was accounted for as compensatory storage. Exact 3D surface comparisons with AutoCAD Civil 3D allow for an extremely accurate volume takeoff for purposes of calculating fill and cut on site. The redeveloped site will have approximately 19,946 cubic yards of fill within the floodplain (below elevation 21.5), while the existing site has only approximately 13,934 CY. See the Proposed Flood Hazard Map in this section. A conveyance system consisting of catch basins and storm pipes will be constructed in the parking areas to collect drainage from impervious surfaces and convey runoff to the proposed water quality facilities. 16836.006.doc Since there are three separate drainage basins located on site, three separate water quality facilities will be used to treat the stormwater runoff, a wetpond, wetvault, and a Filterra unit. C. Performance Standards Per the City of Renton Flow Control Application Map, the project is subject to the Peak Rate Flow Control Standard, in which the project must match developed peak discharge rates to the existing site conditions for the 2-, 10-, and 100-year return periods. Since there will be less impervious area in the proposed condition than there was in the existing condition, flow control will not be needed, as the peak flows from the existing site are larger than the peak flow of the proposed site. See calculations in this section for analysis of peak flows. Per the 2010 City of Renton Amendments to the KCSWDM, the project is subject to Enhanced Basic Water Quality. However, the project is proposing to reduce the water quality requirement in accordance with the 2009 KCSWDM to Basic Water Quality by recording a covenant against title that states that no leachable metals will be proposed in areas of the site exposed to weather. A wetpond, wetvault, and a Filterra unit will be used to provide Basic Water Quality. A wetpond will be used to treat the runoff from the eastern side of the site. The pond will contain a control structure to pass peak flow per conveyance requirements pursuant to the 2009 KCSWDM and the 2010 City of Renton Amendments to the KCSWDM. See the Wetpool Sizing Worksheet in this section. A wetvault will be used to treat the runoff from the northwestern side of the site. The wetvault was designed pursuant to the 2009 KCSWDM and the 2010 City of Renton Amendments to the KCSWDM. See the Wetpool Sizing Worksheet in this section. A Filterra unit will be used to treat the runoff from the southwestern side of the site. WWHM was used to model and size the Filterra unit, meeting the criteria established in the 2009 KCSWDM and the 2010 City of Renton Amendments to the KCSWDM. Per calculations made with WWHM, a 6-foot by 8-foot Filterra unit will be required to fully treat the runoff. See the calculations, City of Renton Blanket Adjustment, and Department of Ecology General Use Level Designation (GULD) for the Filterra unit in this section. D. Flow Control System Per the City of Renton’s flow control map, the site lies within the Peak Rate Flow Control Standard (Existing Site Conditions). The Existing Site Condition references those conditions that existed prior to May 1979. The IKEA store as it exists today was constructed in 1978, so the Existing Site Condition as defined by the KCSWDM is truly the existing site condition as it exists today. As such, the project must match developed peak discharge rates to the existing site conditions for the 2-, 10-, and 100-year storm events. Since the existing site is almost entirely impervious, the proposed site runoff peak flows will be less than the pre-developed existing site condition. Also, there are no existing detention facilities located on site. Therefore, a flow control system will not be required. Per the 2009 KCSWDM and the 2010 City of Renton Amendments to the KCSWDM, flow control BMPs are not required for this site. However, the site does propose a large rain garden at the northeast corner of the site in order to provide some attenuation benefit. 16836.006.doc E. Water Quality System Per the 2010 City of Renton Amendments to the KCSWDM, the project is subject to Enhanced water quality treatment. However, the project is proposing to reduce the water quality requirement in accordance with the 2009 KCSWDM to Basic Water Quality by recording a covenant against title that states that no leachable metals will be proposed in areas of the site exposed to weather. Also, the site is a commercial use site that is not considered a high use site, and it is not associated with vehicular repair, maintenance, or sales. There will be a total of three (3) water quality facilities on site. The proposed wetpond will provide Basic Water Quality for the eastern portion of the site, approximately 18.1 acres. The wetpond was sized per the 2009 KCSWDM, and sizing calculations for the wetpond can be found in this section. The proposed wetvault will provide Basic Water Quality for the northwestern portion of the site, approximately 3.65 acres. An internal wall at the center of the vault was added for structural stability. Without the wall, the vault still complies with the minimum 3:1 flow path length, but the internal wall increases the flow path length. Since the flow path length is greater than 5:1, the vault can be considered a single cell without a baffle wall. Ventilation for the single celled wetvault has been provided over the second half of the vault in accordance with section 6.4 of the 2009 KCSWDM. The wetvault was sized per section 6.4 of the 2009 KCSWDM, and calculations can be found in this section. In addition to standard wetvault sizing calculations, calculations for the 100-year design elevation within the vault have been provided to show that the vault has 6-inches of available head above the overflow pipe. The proposed 6-foot by 8-foot Filterra unit will provide Basic Water Quality for the southwestern portion of the site, approximately 1.01 acres. The Filterra unit was sized per the Washington State Department of Ecology’s standards. Sizing calculations for the Filterra unit can be found in this section. IKEA Contech Engineered Solutions LLC 11815 NE Glenn Widing Dr. Portland, OR 97220 www.ContechES.com June 26, 2015 Will Schuur, E.I.T. Barghausen Consulting Engineers, Inc. 18215 72nd Avenue South Kent, WA 98032 Re: IKEA Redevelopment Renton Project Dear Mr. Schuur: Contech Engineered Solutions, LLC has reviewed the plans prepared by Barghausen Consulting Engineers, Inc. dated 06/11/15 for the IKEA Redevelopment Renton Project. Based on the information provided for review, Contech agrees that the Filterra system designed for the project meet the Filterra General Use Designation Level (GULD) per the Technology Acceptance Protocol – Ecology (TAPE) program and that the following requirements are satisfied: 1. The water quality volume (WQv) will be evenly dispersed, allowing adequate contact time with Filterra’s proprietary bioretention media per the Washington Department of Ecology’s requirements and as modeled through WWHM. 2. Treatment of 91% annual runoff volume is provided as required by TAPE and allowed in the Filterra GULD. 3. Bypass is provided through an approved mechanism: distribution/piping system replicated from the Filterra Internal Bypass – Curb model configuration. 4. All other components of the Filterra system are specified including impermeable walls, media depth, mulch layer, and approved plants. As a result, Contech agrees that this project meets the design requirements outlined in the Filterra GULD issued by Ecology. We are pleased to work with you on this project and look forward to our continued interactions throughout the planning and installation process. Please let me know if we can be of additional assistance. Sincerely, Kathryn Thomason, P.E. Design Engineer – StormFilter Phone: 503-258-3176 kthomason@conteches.com Tab 5.0 16836.006.doc 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN Conveyance calculations are provided herein that have been prepared using the SBUH method allowed by the 2009 KCSWDM. The calculations contained herein include conveyance capacity analysis and a backwater analysis that shows the proposed structures do not overtop the rim for the required design storm event. A conveyance exhibit that delineates the specific catchment areas, and a network tree printout that corresponds to the SBUH conveyance and backwater analysis are also provided in this section. Tab 6.0 16836.006.doc 6.0 SPECIAL REPORTS AND STUDIES The following geotechnical reports are included in this section: 6.1 Report of Geotechnical Engineering Services prepared by GeoDesign Inc. dated December 2, 2014 6.2 Addendum 1 - Pervious Pavements and Pond Slope Stability prepared by GeoDesign Inc. dated February 3, 2015 6.3 Biological Evaluation prepared by Talasaea Consultants, Inc. dated February 27, 2015     REPORT OF GEOTECHNICAL ENGINEERING SERVICES Commercial Warehouse Building Renton, Washington For Greenberg Farrow Architects December 2, 2014 GeoDesign Project: Greenberg-3-04 350 Mission Street SE, Suite 102 l Salem, OR 97302 l 503.385.8439 www.geodesigninc.com December 2, 2014 Greenberg Farrow Architects 19000 MacArthur Boulevard, Suite 250 Irvine, CA 92612 Attention: Mr. Frank Coda Report of Geotechnical Engineering Services Commercial Warehouse Building Renton, Washington GeoDesign Project: Greenberg-3-04 GeoDesign, Inc. is pleased to submit our report for the proposed commercial warehouse building located northwest of the intersection of South 180th Street and Lind Avenue SW in Renton, Washington. The site is currently occupied by the existing IKEA facility. Our services for this project were conducted in accordance with our proposal dated June 19, 2014. We appreciate the opportunity to be of service to you. Please call if you have questions regarding this report. Sincerely, GeoDesign, Inc. Julio C. Vela, Ph.D., P.E. Principal Engineer cc: Mr. Robert Warshefski, Greenberg Farrow Architects (via email only) SPM:JCV:kt Attachments One copy submitted (via email only) Document ID: Greenberg-3-04-120214-geor-rev.docx © 2014 GeoDesign, Inc. All rights reserved.   Greenberg-3-04:120214 TABLE OF CONTENTS PAGE NO. 1.0 INTRODUCTION 1 2.0 PROJECT UNDERSTANDING 1 3.0 PURPOSE AND SCOPE 2 4.0 SITE CONDITIONS 3 4.1 Surface Conditions 3 4.2 Regional Geology 3 4.3 Subsurface Conditions 3 5.0 CONCLUSIONS AND RECOMMENDATIONS 4 5.1 General 4 5.2 Site Preparation 5 5.3 Excavation 7 5.4 Structural Fill 8 5.5 Permanent Slopes 11 6.0 SEISMIC DESIGN CRITERIA 11 6.1 Seismic Design Parameters 11 7.0 FOUNDATION SUPPORT 12 7.1 Shallow Foundations 13 7.2 Deep Foundations/Ground Improvement 14 8.0 FLOOR SLABS 16 9.0 EGRESS TUNNEL 17 10.0 PAVEMENT DESIGN RECOMMENDATIONS 17 11.0 RETAINING STRUCTURES 18 11.1 Assumptions 18 11.2 Wall Design Parameters 19 11.3 Wall Drainage and Backfill 19 12.0 OBSERVATION OF CONSTRUCTION 20 13.0 LIMITATIONS 20 REFERENCES 22 FIGURES Vicinity Map Figure 1 Site Plan Figure 2 Earth Pressure Behind Retaining Walls (Soil + Water + Seismic) Figure 3 Surcharge-Induced Lateral Earth Pressures Figure 4 Greenberg-3-04:120214 TABLE OF CONTENTS PAGE NO. APPENDICES Appendix A Field Explorations A-1 Laboratory Testing A-1 Exploration Key Table A-1 Soil Classification System Table A-2 Boring Logs Figures A-1 – A-12 Atterberg Limits Test Results Figure A-13 Grain-Size Test Results Figure A-14 Summary of Laboratory Data Figure A-15 Appendix B Cone Penetrometer Testing B-1 CPT Logs ACRONYMS 1 Greenberg-3-04:120214 1.0 INTRODUCTION This report presents the results of GeoDesign's geotechnical engineering evaluation for the proposed commercial warehouse building located northwest of the intersection of South 180th Street and Lind Avenue SW in Renton, Washington. Mr. Frank Coda provided us with proposed site layout and development. Initial geotechnical work was conducted in accordance with our February 12, 2013 proposal and was presented in our preliminary geotechnical report dated March 8, 2013. This report presents data included in our preliminary report together with additional subsurface explorations completed for a full site development geotechnical study as described in our June 19, 2014 proposal. Figure 1 shows the site vicinity relative to surrounding features. Figure 2 shows the proposed layout and our approximate exploration locations. For your reference, acronyms used herein are defined at the end of this document. 2.0 PROJECT UNDERSTANDING Greenberg Farrow Architects requested our services for a full site development geotechnical study for the site. Based on a site plan (WA-1d) provided to us by Greenberg Farrow Architects, a new approximately 406,000-square-foot building is to be constructed on the west portion of the property with a parking field in the east portion. The proposed store site is occupied by a parking structure for the adjacent existing retail facility. The existing retail facility is located to the east in the proposed parking field area. Greenberg Farrow Architects also provided construction drawings for the existing structures, which indicate that they were both established on shallow foundations. We understand that the existing retail structures will be demolished to accommodate the new parking field. Fills up to 1 foot are planned across the new building pad in order to raise site grades. The finished floor will be at an elevation of 25 feet, which is approximately 4 to 5 higher than the surrounding parking lot elevation. An approximately 12-foot-deep egress tunnel is planned below the proposed building. Greenberg Farrow Architects indicated that the following maximum structural loads are planned for the structure:  Columns: 400 to 500 kips  Walls: 9 kips per foot  Floors: 300 psf (maximum live load) Project traffic design loads are as described in the site criteria requirements manual as follows: a. Standard-duty pavement loading consists of 50,000 18-kip ESALs based on a 10-year pavement design life and 3,500 vehicle passes per day b. Heavy-duty loading consists of 220,000 18-kip ESALs based on a 10-year pavement design life with 26 semi-trailer trucks per day 2 Greenberg-3-04:120214 3.0 PURPOSE AND SCOPE The purpose of our services was to conduct additional explorations across the site in order to characterize subsurface soil and groundwater conditions to provide the basis for full geotechnical design recommendations for site development. This scope of work is designed to supplement the field work and preliminary recommendations provided in our March 8, 2013 report. The specific scope of our proposed services is summarized as follows:  Coordinated and managed the supplemental field investigation, including locating utilities, access preparation, and scheduling of contractors and GeoDesign staff.  Reviewed readily available geotechnical and geologic information for the site area and incorporate preliminary data and recommendations to the proposed supplemental study.  Explored subsurface soil and groundwater conditions for proposed building and parking areas by conducting 17 additional explorations (a proposed 18th exploration location at the northwest corner of the parking structure was not accessible to our equipment). The following explorations were completed:  Four additional mud rotary drilled borings in the proposed building area to a depth of 91.5 feet BGS  Seven additional CPT probes in the proposed building area to depths of approximately 90 feet BGS  Six shallow borings in the proposed parking field area to a depth of 11.5 feet BGS  Classified the materials encountered in the borings in general accordance with ASTM D 2488, and maintained a detailed log of each exploration.  Completed laboratory moisture, grain-size, and Atterberg limits tests on selected samples obtained from the explorations to determine pertinent engineering characteristics of the site soil. Laboratory testing was conducted in general accordance with appropriate ASTM test methods.  Provided recommendations for site preparation, grading and drainage, stripping depths, use of demolished material, fill type for imported material, compaction criteria, cut and fill slope criteria, temporary excavations, use of on-site soil, and wet/dry weather earthwork.  Provided geotechnical engineering recommendations for design and construction of shallow spread foundations, including allowable design bearing pressure and minimum footing depth and width.  Provided geotechnical engineering recommendations for the design and construction of concrete floor slabs, including an anticipated value for subgrade modulus.  Estimated settlement of footings and floor slabs for the design loadings.  Recommended design criteria for retaining walls, including lateral earth pressure, allowable bearing pressure for retaining wall footings, backfill type, compaction requirements, and drainage.  Evaluated design pavement sections, including base course and AC thicknesses, for both standard- and heavy-duty pavements for parking areas and access roads based on the traffic data provided to us by others.  Provided recommendations for the International Building Code site coefficient and seismic zone and our evaluation of the liquefaction and lateral spreading potential of site soil.  Provided this report summarizing the results of our geotechnical evaluation, including geotechnical design and construction recommendations. 3 Greenberg-3-04:120214 Exploration locations were backfilled with bentonite chips per Washington well drilling requirements upon completion. The upper portion of the hole was backfilled with soil cuttings or crushed rock and capped at the surface with cold-patch AC mix or cement grout for a solid finish. Cuttings from the borings were drummed and hauled off site. 4.0 SITE CONDITIONS 4.1 SURFACE CONDITIONS The site is located northwest of the intersection of South 180th Street and Lind Avenue SW in Renton, Washington. The site is currently occupied by an existing retail store and a parking structure, which encompasses most of the site area. The existing buildings are surrounded by paved parking and driveways. There are dock-high truck access points around the perimeter of both existing structures, which indicate fill beneath the building portion at least to a dock-high elevation (approximately 4 feet above adjacent parking grades). There are small warehouse-type businesses that are in operation in the west portion of the west building as well. Paved (and presumably filled) ramps abut the building to access the dock-high floors for some of those businesses as well as between the parking structure and the existing retail building. There are small to mature trees in the grass-covered landscaped strips between the site and local roads. The site area is surrounded by commercial properties. The ground surface is generally flat to gently sloped 4.2 REGIONAL GEOLOGY 4.2.1 Geologic Setting The site is located south of the City of Renton, Washington. The local geologic unit is mapped as recent alluvial deposits (Mullineaux, 1965). The alluvial deposits consist of sand, silt, and clay deposited by the White and Green rivers. There are channel gravels and thin peat lenses within the soil unit. The upper portion of this unit is comprised mainly of sand, silt, and clay. The lower portion is comprised mainly of medium and coarse sand. Earthquakes within the site vicinity are caused by intraslab earthquakes within the North American Plate. No known faults exist within the site boundaries; the closest known potentially active fault is the Seattle Fault Zone mapped approximately 6 miles north of the site. 4.3 SUBSURFACE CONDITIONS We explored subsurface conditions by completing 12 borings (B-1 through B-12) to depths of 11.5 to 111.5 feet BGS and eight CPT probes (CPT-1 through CPT-8) to approximate depths of 90 feet BGS. The approximate exploration locations are shown on Figure 2. Descriptions of the subsurface explorations and laboratory testing programs, as well as the boring logs, are presented in Appendix A. The CPT logs are presented in Appendix B. In general, the subsurface conditions consist of interbedded layers of silt and sand to the maximum depth explored. Our borings encountered approximately 1.5 to 5 inches of AC and approximately 2 to 5 feet of gravel/sand fill. The following sections present a description of the soil units encountered in our explorations. 4 Greenberg-3-04:120214 4.3.1 Fill Imported granular fill was likely used to raise site grades for the existing building to dock-high level. The fill consists mainly of gravel with small amounts of fine sand. We also encountered zones of clean sand and sand with some gravel in the fill. SPT results and our observations indicate that the fill material is generally medium dense to dense. Borings around the building area (B-1 through B-6) generally encountered the fill soil to a depth of 4.5 to 5 feet BGS. Other borings, located in the neighboring parking area, encountered fill to depths generally of 2 to 3.5 feet. 4.3.2 Sandy Silt/Silty Sand Our explorations encountered interbedded layers of sandy silt and silty sand below the fill to depths ranging between approximately 25 and 50 feet BGS. The sand particles are generally fine grained. Based on SPT results, the silt layers in this unit are generally soft to medium stiff while the sand layers are generally medium dense with some loose and dense zones. Laboratory testing indicates that the moisture content of the silt layers generally ranged from 42 to 114 percent and the moisture content of the sand layers ranged from 16 to 43 percent at the time of our explorations. Testing also indicated that the silt has high plasticity and samples of the sand had fines contents of 6 to 15 percent. 4.3.3 Lower Silt Our explorations encountered silt soil below the upper silty sand/sandy silt unit to depths ranging between approximately 95 and 110 feet BGS. This unit contains varying amounts of fine-grained sand particles. Based on SPT results, the silt is generally very soft. Laboratory testing indicates that the moisture content of the silt ranged from 39 to 56 percent at the time of our explorations. Selected samples had sand contents between 12 and 15 percent. This soil unit likely has high compressibility characteristics. 4.3.4 Lower Sand Our explorations encountered sand soil below the very soft silt to the maximum depth explored. Based on SPT results, the sand is very dense. 4.3.5 Groundwater We did not observe groundwater in our borings due to the presence of drilling fluid. The CPT probes indicate that groundwater is approximately 8 to 10 feet BGS. The depth to groundwater is expected to fluctuate and could be as shallow as 5 to 6 feet BGS in response to seasonal changes, changes in surface topography, and other factors not observed in the site vicinity. 5.0 CONCLUSIONS AND RECOMMENDATIONS 5.1 GENERAL Based on the results of our subsurface explorations and analyses, it is our opinion that the following general considerations will be critical for the planned project:  Our analyses indicate that up to 2.5 inches of liquefaction-induced settlement is possible at the site during the design earthquake. We recommend that structural design of shallow foundations and floor slabs account for liquefaction-induced settlement. Some minor 5 Greenberg-3-04:120214 structural damage should still be expected, such as cracked walls and racked door and windows. If these settlements are not acceptable to the project owner, a deep foundation system or ground improvement will be necessary for liquefaction mitigation as discussed in the “Deep Foundations/Ground Improvement” section of this report.  If the building is established on conventional shallow footings, all foundation bearing surfaces be compacted in accordance with the “Structural Fill” section of this report.  While the on-site gravel/sand fill soil was generally found to be medium dense, it is possible that some loose zones exist. The project budget should include a contingency for improving portions of the pavement and floor slab subgrade.  Groundwater could rise above the bottom of the proposed egress tunnel. The tunnel should be waterproofed and designed to resist buoyant uplift forces and lateral hydrostatic forces due to the groundwater that may be as shallow as 5 feet BGS.  Existing structures (including foundations) and pavements should be completely removed from within, and at least 5 feet outside of, planned structural areas.  The on-site gravel/sand fill is generally suitable for use as structural fill provided it is properly moisture conditioned. The native silt soil has high moisture content and will be difficult to adequately compact during most times of the year.  The on-site gravel/sand fill will generally provide adequate support for construction traffic during the wet season provided that at least 18 inches of the fill remains in place. The following sections present specific preliminary geotechnical recommendations for design and construction of the proposed development. 5.2 SITE PREPARATION 5.2.1 Stripping and Grubbing If development extends into vegetated areas, the existing topsoil zone and vegetation should be stripped and removed from all proposed structural fill, pavement, and improvement areas and for a 5-foot margin around such areas. The average depth of stripping is expect to be 2 to 4 inches, although greater stripping depths may be required to remove localized zones of loose or organic soil. The actual stripping depth should be based on field observations at the time of construction. Stripped material should be transported off site for disposal or used in landscaped areas. Existing trees and shrubs should be removed from all pavement and improvement areas. In addition, root balls should be grubbed out to the depth of the roots, which could exceed 2.5 feet BGS. Depending on the methods used to remove the root balls, considerable disturbance and loosening of the subgrade could occur during site grubbing. We recommend that soil disturbed during grubbing operations be removed to expose firm, undisturbed subgrade. The resulting excavations should be backfilled with structural fill. 5.2.2 Demolition Demolition should include complete removal of existing structures, slabs, and asphalt within 5 feet of areas to receive new pavements, buildings, retaining walls, or engineered fill. This should include complete removal of buried foundations. Underground utility lines, vaults, or tanks encountered in areas of new improvements should be completely removed or, with prior approval, grouted full if left in place. 6 Greenberg-3-04:120214 Old basement or crawlspace areas, if present, or voids resulting from removal of improvements or loose soil in utility lines should be backfilled with compacted structural fill, as discussed in the “Structural Fill” section of this report. The bottom of such excavations should be excavated to expose a firm subgrade before filling and their sides sloped at a minimum of 1H:1V to allow for more uniform compaction at the edges of the excavations. Material generated during demolition should be transported off site for disposal or stockpiled in areas designated by the owner. It may be possible to use crushed concrete and asphalt in parking or landscaped areas provided it is placed at least 2 feet below asphalt pavement (see “Structural Fill” section of this report). 5.2.3 Subgrade Evaluation Upon completion of stripping and excavation, and prior to the placement of fill or pavement improvements, the exposed subgrade should be evaluated by proof rolling. The subgrade should be proof rolled with a fully loaded dump truck or similarly heavy, rubber-tired construction equipment to identify soft, loose, or unsuitable areas. A member of our geotechnical staff should observe the proof rolling to evaluate yielding of the ground surface. During wet weather, subgrade evaluation should be performed by probing with a foundation probe rather than proof rolling. Areas that appear soft or loose should be improved in accordance with following section of this report. 5.2.4 Subgrade Improvement Up to 5 feet of undocumented fill soil is present at the ground surface across the site. Although it was found to be generally medium dense to dense, reliable strength properties are difficult to predict for undocumented fill. There is a risk for poor performance of floor slabs and pavements established directly over soft/loose zones of fill soil. In order to reduce the risk of settlement, we recommend that areas identified as soft/loose during site preparation be improved by removing and replacing with structural fill or scarifying and re-compacting the on-site soil to structural fill requirements. Improvement should occur to a depth of at least 12 inches and before structural fill is placed. A member of our geotechnical staff should observe all subgrade areas to help identify unsuitable undocumented fill soil. The project budget should include a contingency for subgrade improvement over a portion of the site. 5.2.5 Wet Weather/Wet Soil Grading The surficial soil (below the AC) encountered in our explorations consists of a gravel soil with some sand. This granular soil will generally provide satisfactory support for construction equipment during periods of moderate wet weather provided at least 18 inches of the material remains after site grading. The underlying soil at the site is silty and easily disturbed during the wet season and when it is moist. If less than 18 inches of the overlying gravel/sand soil remains after grading, repeated construction traffic can create extensive soft areas and significant subgrade repair costs can result. If construction is planned when the surficial soil is wet or may become wet and less than 18 inches of the on-site soil remains, the construction methods and schedule should be carefully 7 Greenberg-3-04:120214 considered with respect to protecting the subgrade to reduce the need to over-excavate disturbed or softened soil. The project budget should reflect the recommendations below if this is the case. The thickness of the granular material for haul roads and staging areas will depend on the amount and type of construction traffic. Generally, a 12- to 18-inch-thick mat of granular material is sufficient for light staging areas and the basic building pad but is generally not expected to be adequate to support heavy equipment or truck traffic. The granular mat for haul roads and areas with repeated heavy construction traffic typically needs to be increased to between 18 and 24 inches. The actual thickness of haul roads and staging areas should be based on the contractor’s approach to site development and the amount and type of construction traffic. The gravel/sand soil present at the site can serve as haul roads/staging areas. New granular material should be placed in one lift over the prepared, undisturbed subgrade and compacted using a smooth-drum, non-vibratory roller. The granular material should meet the specifications for imported granular material or stabilization material in the “Structural Fill” section of this report. In addition, a geotextile fabric can be placed as a barrier between the subgrade and imported granular material in areas of repeated construction traffic. The geotextile should have a minimum Mullen burst strength of 250 psi for puncture resistance and an AOS between U.S. Standard No. 70 and No. 100 Sieves. 5.3 EXCAVATION Excavation in the on-site soil should be possible with conventional earthmoving equipment. Cuts in the on-site soil unit may experience some caving at depths less than 4 feet. Open excavation techniques may be used to excavate trenches provided the walls of the excavation are cut at a slope of 1H:1V, water seepage is not present, and with the understanding that some sloughing may occur. If excessive caving occurs, the trenches should be flattened to 1½H:1V or 2H:1V if workers are required to enter. 5.3.1 Dewatering Groundwater may be encountered at depths of 8 feet BGS, or shallower, depending on the time of year. Deep excavation could require dewatering. Dewatering for excavations proceeding several feet below groundwater can likely be accomplished by pumping from sumps. Positive control of groundwater will be required to maintain stable trench sides and base. Because of the instability of saturated soil, sloughing and “running conditions” can occur when the excavation extends below the groundwater seepage levels. The proposed dewatering plan should be capable of maintaining groundwater levels below the base of the trench excavation, including the depth required for trench bedding and stabilization material. Flow rates for dewatering are likely to vary depending on location, soil type, and the season in which the excavation occurs and may require a very intensive use of sumps or the use of well points. The dewatering systems should be capable of adapting to variable flows. Profiling of the water may be required to identify proper disposal. Excavations proceeding more than several feet below the groundwater table may require more extensive dewatering techniques, such as installation of well points. Tight-joint, driven sheets, in conjunction with a scaled-down dewatering program, can also be an effective way to control groundwater seepage, provided the sheets are driven deep enough to control heaving conditions at the base of the excavation. 8 Greenberg-3-04:120214 5.3.2 Safety All excavations should be made in accordance with applicable OSHA requirements and regulations of the state, county, and local jurisdiction. 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 structural elements. 5.4 STRUCTURAL FILL 5.4.1 General Structural fill includes material placed beneath foundations, slabs, pavements, any other areas intended to support structures or within the influence zones of structures. Structural fill should be free of organic matter and other deleterious material and, in general, should consist of particles no larger than 4 inches in diameter. Smaller maximum particle sizes will be necessary for some applications. The workability of material for use as structural fill will depend on the gradation and moisture content of the soil. As the amount of fines (material passing the U.S. Standard No. 200 Sieve) increases, soil becomes increasingly sensitive to small changes in moisture content and adequate compaction becomes more difficult, if not impossible, to achieve. As the amount of coarse gravel increases, fill material tends to segregate as it is being fine-graded with coarser material being pushed out the leading edge of the fill being placed, which results in an unsatisfactory material gradation. 5.4.2 On-Site Soil The on-site granular soil is generally suitable for use as structural fill during most of the year. Soil with higher silt content may be difficult to compact during wet weather. The native silt soil will be difficult, if not impossible, to compact at all times of the year due to the high moisture content. Extensive drying during the summer months only will likely be required to use on-site silt for structural fill. When used as structural fill, the on-site silt soil should be placed in lifts with a maximum uncompacted thickness of 8 inches and compacted to not less than 92 percent of the maximum dry density, as determined by ASTM D 1557. On-site granular soil should be placed with a maximum thickness of 12 inches and compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D 1557. 5.4.2.1 Imported Granular Material Imported granular material used as structural fill should be pit- or quarry-run rock, crushed rock, or crushed gravel and sand and should meet the specifications provided in WSS 9-03.9(1) - Ballast, WSS 9-03.14(1) - Gravel Borrow, or WSS 9-03.14(2) - Select Borrow. The imported granular material should also be angular, fairly well graded between coarse and fine material, have less than 5 percent by dry weight passing the U.S. Standard No. 200 Sieve, and have at least two mechanically fractured faces. 9 Greenberg-3-04:120214 Imported granular material should be placed in lifts with a maximum uncompacted thickness of 12 inches and compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D 1557. During the wet season or when wet subgrade conditions exists, the initial lift should be approximately 18 inches in uncompacted thickness and should be compacted by rolling with a smooth-drum roller without using vibratory action. 5.4.2.2 Stabilization Material Stabilization material used in staging or haul road areas, trench stabilization material, or other applications should consist of 4- or 6-inch-minus pit- or quarry-run rock, crushed rock, or crushed gravel and sand. The material should have a maximum particle size of 6 inches, less than 5 percent by dry weight passing the U.S. Standard No. 4 Sieve, and at least two mechanically fractured faces. The material should be free of organic matter and other deleterious material. Stabilization material should be placed in lifts between 12 and 24 inches thick and compacted to a firm condition. 5.4.2.3 Trench Backfill Trench backfill placed beneath, adjacent to, and for at least 12 inches above utility lines (i.e., the pipe zone) should consist of well-graded granular material with a maximum particle size of 1½ inches and less than 10 percent by dry weight passing the U.S. Standard No. 200 Sieve and should meet the specifications provided in WSS 9-03.12(3) - Gravel Backfill for Pipe Zone Bedding. The pipe zone backfill should be compacted to at least 90 percent of the maximum dry density, as determined by ASTM D 1557, or as required by the pipe manufacturer or local building department. Within roadway alignments, the remainder of the trench backfill up to the subgrade elevation should consist of well-graded granular material with a maximum particle size of 2½ inches and less than 10 percent by dry weight passing the U.S. Standard No. 200 Sieve and should meet the specifications provided in WSS 9-03.19 - Bank Run Gravel for Trench Backfill. This material should be compacted to at least 90 percent of the maximum dry density, as determined by ASTM D 1557, or as required by the pipe manufacturer or local building department. The upper 3 feet of the trench backfill should be compacted to at least 95 percent of the maximum dry density, as determined by ASTM D 1557. Outside of structural improvement areas (e.g., roadway alignments or building pads) trench backfill placed above the pipe zone may consist of general fill material that is free of organics and material over 6 inches in diameter and meets the specifications provided in WSS 9-03.14(3) - Common Borrow and WSS 9-03.15 - Native Material for Trench Backfill. This general trench backfill should be compacted to at least 90 percent of the maximum dry density, as determined by ASTM D 1557, or as required by the pipe manufacturer or local building department. 5.4.2.4 Drain Rock Drain rock should consist of angular, granular material with a maximum particle size of 2 inches. The material should be free of roots, organic matter, and other unsuitable material; have less than 2 percent by dry weight passing the U.S. Standard No. 200 Sieve (washed analysis); and have at least two mechanically fractured faces. Drain rock should be compacted to a well-keyed, firm condition. 10 Greenberg-3-04:120214 5.4.2.5 Aggregate Base Rock Imported granular material used as base rock for building floor slabs and pavements should consist of ¾- or 1½-inch-minus material (depending on the application) and meet the requirements in WSS 9.03.9 - Aggregates for Ballast and Crushed Surfacing. In addition, the aggregate should have less than 5 percent by dry weight passing the U.S. Standard No. 200 Sieve and have a minimum of two mechanically fractured faces. The base aggregate should be compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D 1557. 5.4.2.6 Retaining Wall Select Backfill Backfill material placed behind retaining walls and extending a horizontal distance of ½H, where H is the height of the retaining wall, should consist of select granular material that meets the specifications provided in WSS 9-03.12(2) - Gravel Backfill for Walls. We recommend the select granular wall backfill be separated from general fill, native soil, and/or topsoil using a geotextile fabric that meets the specifications provided below for drainage geotextiles. The wall backfill should be compacted to a minimum of 95 percent of the maximum dry density, as determined by ASTM D 1557. However, backfill located within a horizontal distance of 3 feet from a retaining wall should only be compacted to approximately 90 percent of the maximum dry density, as determined by ASTM D 1557. Backfill placed within 3 feet of the wall should be compacted in lifts less than 6 inches thick using hand-operated tamping equipment (such as a jumping jack or vibratory plate compactor). If flatwork (sidewalks or pavements) will be placed atop the wall backfill, we recommend that the upper 2 feet of material be compacted to 95 percent of the maximum dry density, as determined by ASTM D 1557. 5.4.3 Geotextile Fabric Drainage geotextile should conform to WSS 9-33.2 – Geotextile Properties for drainage geotextiles. The geotextile should have a Level “B” certification. A minimum initial aggregate base lift of 6 inches is required over geotextiles. 5.4.4 Recycled On-Site Material Demolished concrete and AC materials may be used on site as structural fill, provided they can be processed to meet the requirements for their intended use. Processing includes crushing and screening, grinding in place, or other methods to meet the requirements for structural fill as described above. The processed material should be fairly well graded and not contain metal, organic, or other deleterious material. The processed material should be mixed with on-site soil or imported fill to assist in achieving the gradation requirements. We recommend that processed, recycled fill have maximum particle sizes as presented in Table 1. 11 Greenberg-3-04:120214 Table 1. Processed Fill Maximum Particle Size Depth of Placement1 (feet) Maximum Particle Size (inches) 0 to 2 Not recommended 2 to 4 4 4 to 6 6 deeper than 6 8 1. below subgrade of structural element Recycled on-site fill material should not be used within a depth of 2 feet from foundations, floor slabs, pavements, or other subsurface elements. Recycled material should not be used within 10 feet of the planned egress tunnel, for drainage purposes. We also caution that excavation through recycled material that is placed as structural fill may be difficult due the significant fraction of oversized particles. In addition, these excavations may also be prone to raveling and caving. 5.5 PERMANENT SLOPES Permanent cut and fill slopes should not exceed 2H:1V. Access roads and pavements should be located at least 5 feet from the top of cut and fill slopes. The setback should be increased to 10 feet for buildings. The slopes should be planted with appropriate vegetation to provide protection against erosion as soon as possible after grading. Surface water runoff should be collected and directed away from slopes to prevent water from running down the face of the slope. 6.0 SEISMIC DESIGN CRITERIA 6.1 SEISMIC DESIGN PARAMETERS Based on our investigation, the following design parameters are applicable if the building is designed using provisions of the 2012 IBC (ASCE 7-10) for the existing on-site soil conditions. The results of SPT and CPT testing indicate that the site should have a Seismic Site Class E designation. The seismic design parameters in Table 2 are appropriate for structural design for this site. 12 Greenberg-3-04:120214 Table 2. Seismic Design Parameters Parameter Short Period (Ts = 0.2 second) 1 Second Period (T1 = 1.0 second) MCE Spectral Acceleration, S Ss = 1.40 g S1 = 0.52 g Site Class E Site Coefficient, F Fa = 0.90 Fv = 2.40 Adjusted Spectral Acceleration, SM SMS = 1.26 g SM1 = 1.25 g Design Spectral Response Acceleration Parameters, SD SDS = 0.82 g SD1 = 0.84g Design PGA, SaPGA 0.33 g 6.1.1 Seismic Hazards Liquefaction can be defined as the sudden loss of shear strength in a soil due to an excessive buildup of pore water pressure. Liquefied soil layers generally follow a path of least resistance to dissipate pore pressures, often resulting in sudden surface settlement, sand boils or ejections, and/or lateral spreading in extreme cases. Clean, loose, uniform or silty, fine-grained, saturated sand is particularly susceptible to liquefaction. Lateral spreading is a liquefaction-related seismic hazard. Areas subject to lateral spreading are typically gently sloping or flat sites underlain by liquefiable sediment adjacent to an open face, such as riverbanks. Liquefied soil adjacent to open faces may “flow” in that direction, resulting in lateral displacement and surface cracking. Our analyses indicate that discrete layers of sand and silty sand encountered at the site are susceptible to liquefaction during a design-level earthquake. We anticipate that liquefaction- induced settlement observed at the ground surface would likely be in the range of 1 inch to 2.5 inches. Differential settlement could approach total settlement. In our experience, this is not considered to be a life safety hazard, and structural design should be able to accommodate these settlement magnitudes, provided those settlements are tolerable for operational needs. We performed a seismic site response analysis using the SHAKE 91+ module of the EZ-FRISK 7.62 software package to determine site response during the design earthquake. The results indicate that ground motion amplification in the on-site soil is unlikely and spectral acceleration values at the ground surface should not exceed those prescribed by ASCE 7-10 using the parameters defined in Table 2. 7.0 FOUNDATION SUPPORT Building elements established on shallow foundations may be subject to up to 2.5 inches of liquefaction-induced settlement during the design earthquake. Differential settlement could approach total estimated magnitudes. In our opinion, these settlement magnitudes are very unlikely to result in building collapse and pose a low life safety hazard, provided that structural design of foundations and floor slabs account for liquefaction-induced settlement. Some minor 13 Greenberg-3-04:120214 structural damage should still be expected, such as cracked walls and racked door and windows. If this settlement is not acceptable to the project owner, a deep foundation system or ground improvement will be necessary for liquefaction mitigation as discussed in the “Deep Foundations/Ground Improvement” section of this report. The following sections provide recommendations for shallow foundations, if selected for this project. 7.1 SHALLOW FOUNDATIONS Based on the design foundation loads previously stated, the project grading plan, and provided the structure is designed to tolerate the anticipated liquefaction-induced settlement (see “Seismic Design Criteria” section of this report), it is our opinion the proposed structure can be supported on conventional shallow footings bearing on the gravel fill soil. We recommend that the all foundation bearing surfaces be compacted in accordance with the “Structural Fill” section of this report before concrete footings are constructed. We recommend that footings not be embedded more than 2 feet below planned finished floor elevation so that at least 2 feet of existing gravel fill will be present below the footings. Where bottom of footings extend below the existing gravel fill, 2-foot-thick granular pads (compacted crushed rock) should be installed below the footings. Granular pads should extend outward from the edge of the footing at least 6 inches per foot of depth. 7.1.1 Liquefaction-Induced Settlement As discussed in the “Seismic Considerations” section of this report, the native soil at the site is subject to liquefaction during the design earthquake. We estimate that liquefaction-induced settlement could range from approximately 1 inch to 2.5 inches at the ground surface. Differential settlement could approach the same magnitudes. We recommend that structural design of foundations and floor slabs account for liquefaction-induced settlement. If this settlement is not acceptable, a deep foundation system or ground improvement (See “Deep Foundations/Ground Improvement” section) will be necessary for liquefaction mitigation. 7.1.2 Dimensions and Capacities Continuous wall and isolated spread footings should be at least 16 and 20 inches wide, respectively. The bottom of exterior footings should be at least 18 inches below the lowest adjacent exterior grade. The bottom of interior footings should be established at least 12 inches below the base of the slab. As discussed previously, we recommend that foundations not be embedded more than 2 feet below finished grade, in order maximize the amount of gravel fill material overlying the soft silt layer encountered in our explorations. Footings established on on-site soil or fine-grained structural fill soil and prepared as recommended above should be sized based on an allowable bearing pressure of 2,500 psf. This is a net bearing pressure; the weight of the footing and overlying backfill can be ignored in calculating footing sizes. The recommended allowable bearing pressure applies to the total of dead plus long-term live loads and can be increased by one-third for short-term loads (such as those resulting from wind or seismic forces). 7.1.3 Static Foundation Settlement Settlement magnitudes under static loads are proportional to the size, depth, and type of foundation used. Settlement potential at a given bearing pressure increases with the width of 14 Greenberg-3-04:120214 the footing and is usually greater for wall footings than column footings. Foundations designed and constructed as recommended in this report are expected to experience less than 1 inch of post-construction settlement due to static loads. Post-construction differential settlement of less than ½ inch (one-half of the total settlement magnitude) can be expected between adjacent footings with similar loads. This does not include liquefaction-induced settlement previously discussed. 7.1.4 Resistance to Sliding Lateral loads on footings can be resisted by passive earth pressure on the sides of the structures and by friction on the base of the footings. Our analysis indicates that the available passive earth pressure for footings confined by on-site fill soil is 350 pcf, modeled as an equivalent fluid pressure. Typically, the movement required to develop the available passive resistance may be relatively large; therefore, we recommend using a reduced passive pressure of 250 pcf equivalent fluid pressure. Adjacent floor slabs, pavements, or the upper 12-inch depth of adjacent unpaved areas should not be considered when calculating passive resistance. In addition, in order to rely on passive resistance, a minimum of 10 feet of horizontal clearance must exist between the face of the footings and any adjacent down slopes. For footings in contact with the gravel fill, a coefficient of friction equal to 0.40 may be used when calculating resistance to sliding. 7.1.5 Construction Considerations All footing and floor subgrades should be evaluated by the project geotechnical engineer or their representative to confirm suitable bearing conditions. Observations should also confirm that all loose or soft material, organics, unsuitable fill, prior topsoil zones, and softened subgrades (if present) have been removed and that the gravel fill material has been compacted in accordance with our recommendations. Localized deepening of footing excavations may be required to penetrate deleterious material. 7.2 DEEP FOUNDATIONS/GROUND IMPROVEMENT 7.2.1 Liquefaction Mitigation Liquefaction mitigation systems can consist of ground improvement (such as cement grout columns and stone columns) or a deep foundation system (such as piles). Preliminary information indicates that ground improvement by cement grout columns or stone columns will provide sufficient structural support and will likely be the most economical solution for the site. They are often used in conjunction with other improvement methods, such as wick drains. Pile foundations will likely not be as economical a solution for site development because of the lack of a suitable, relatively shallow end bearing soil layer and the lower frictional capacity compared to ground improvement methods. We recommend that improvement, or deep foundations, be considered if liquefaction-induced settlement is not acceptable for development. Utilities lines should be installed with flexible connections into the building to allow for some differential settlement due to liquefaction. Alternately, a cement grout- or stone column- supported utility corridor could be developed to bring utilities into the building. It is likely that pavements and utilities will require some repair due to liquefaction-induced settlement in the event of a design magnitude earthquake. If cement grout columns or stone columns are 15 Greenberg-3-04:120214 selected, we recommend they extend to a depth of at least 50 feet BGS, which is the depth to which liquefaction is expected to occur. These types of ground improvement systems are typically designed and provided by design-build specialty contractors. Grout cement columns are a ground improvement technique that involves the blending of cement with native soil. A revolving hollow-stem auger with mixing paddles is typically advanced while grout is pumped through the hollow stem of the revolving shaft and discharged laterally along the lower mixing paddle where it is mixed with the with the native soil. The resulting column is a blended mixture of native soil and cement grout, which will cure and harden over time. Stone columns consist of crushed rock or gravel injected into the ground to form columns below the building footprint. Stone columns are typically installed by vibration. Many cement grout and stone column systems are proprietary and are provided by specialty contractors on a design-build basis. If selected for this project, we recommend that design of the system be accomplished by a specialty design-build contractor. We recommend that GeoDesign be allowed to review the final design and proposed installation method(s) for the cement grout or stone column system. If piles are selected, GeoDesign can provide recommendations for geotechnical design. A representative of our firm should monitor ground improvement or deep foundation installation and subsequent quality testing and review the data obtained to confirm that the expected liquefaction mitigation can be achieved. 7.2.2 Shallow Foundation Capacities with Ground Improvement Footings established on on-site soil that have been improved by inclusion of stone columns may be capable of increased soil bearing pressures of up to 3,000 psf if included as a part of ground improvement design. The concentration of stone columns would likely need to be increased at specified footing locations. As an example, while slab on grade building areas would be designed to a stone column area replacement ration of 10 to 12 percent, footing areas replacement ratios would be increased to 20 to 24 percent by inclusion of additional stone columns, depending on the ground improvement contractor’s design and desired recommended bearing pressure. The additional stone columns would typically extend to a depth of 2.5 times the least footing width. The total recommended allowable bearing pressure from ground improvement design should apply to the total of dead plus long-term live loads. 7.2.3 Seismic Design Parameters with Ground Improvement Seismic design parameters established in Table 2 are based on the average shear wave velocity approach outlined in the IBC. Weighted average calculations for shear wave velocity based on CPT data were used to a depth of 100 feet BGS. The average shear wave velocity in a soil layer is increased by inclusion of compacted stone columns. Assuming a minimum stone column area replacement ratio of 11 percent for 50-foot deep stone columns, and an average shear wave velocity of 1,100 fps in the compacted stone columns, a revised average shear wave velocity was calculated for the improved soil layer. Based on the improved average shear wave velocity, the design parameters presented in Table 3 are applicable if the building is designed using provisions of the 2012 IBC (ASCE 7-10). 16 Greenberg-3-04:120214 Table 3. Seismic Design Parameters (50-Foot-Deep Ground Improvement by Stone Columns) Parameter Short Period (Ts = 0.2 second) 1 Second Period (T1 = 1.0 second) MCE Spectral Acceleration, S Ss = 1.41 g S1 = 0.53 g Site Class D Site Coefficient, F Fa = 1.0 Fv = 1.5 Adjusted Spectral Acceleration, SM SMS = 1.41 g SM1 = 0.80 g Design Spectral Response Acceleration Parameters, SD SDS = 0.94 g SD1 = 0.53g Design PGA, SaPGA 0.38 g 8.0 FLOOR SLABS Satisfactory subgrade support for floor slabs supporting up to the estimated 300 psf areal loading can likely be obtained based on the project grading plan. This includes up to 1 foot of new fill placed across the building footprint. If final site grades change from current plans, the recommendations in this report may need to be revised. As discussed in the “Foundation Support” section of this report, slabs will still be subject to liquefaction-induced settlement during the design earthquake. Floor slabs should be designed to tolerate the estimated settlement amounts, or supported by improved ground or deep foundations. As discussed in the “Site Preparation” section of this report, subgrade improvement may be necessary before new fill placement in some slab areas where soft/loose fill soil is encountered. Slabs should be reinforced according to their proposed use and per the structural engineer’s recommendations. Load-bearing concrete slabs may be designed assuming a modulus of subgrade reaction (k) of 150 psi per inch. We recommend a minimum 8-inch-thick layer of aggregate base be placed and compacted over the prepared soil subgrade. Imported granular material placed beneath building floor slabs should meet the requirements in the “Structural Fill” section of this report. The aggregate base should be placed in one lift and compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D 1557. Flooring manufacturers often require vapor barriers to protect flooring and flooring adhesives. Many flooring manufacturers will warrant their product only if a vapor barrier is installed according to their recommendations. Selection and design of an appropriate vapor barrier (if needed) should be based on discussions among members of the design team. 17 Greenberg-3-04:120214 9.0 EGRESS TUNNEL We understand that an approximately 10-foot-deep egress tunnel is planned to be constructed below the building. We estimate that groundwater is 8 to 10 feet below the existing parking lot grade, where our borings were located. Considering that the building will be 4 to 5 feet higher than the parking lot grade, it is likely that the groundwater was 12 to 15 feet below planned finished floor grade at the time of our investigation. It is likely that groundwater will periodically rise to above the bottom of the tunnel, especially during periods of wet weather. As discussed in the “Subsurface Conditions” section above, the depth of groundwater could be as shallow as 5 to 6 feet BGS (below existing parking lot grade) in response to seasonal changes. We recommend that the tunnel walls be waterproofed to prevent infiltration of rising groundwater. The tunnel and slab overlying the tunnel structure should also be designed to resist buoyant forces resulting from elevated groundwater. Hydrostatic lateral forces and lateral forces resulting from loads across the floor slab should be included in the design of the tunnel walls. Figures 3 and 4 describe lateral earth pressures for wall design that include lateral forces from hydrostatic pressure and surcharge loads for a restrained wall. The contractor should be prepared to dewater and shore the tunnel excavation during construction as described in the “Excavation” section of this report. 10.0 PAVEMENT DESIGN RECOMMENDATION Pavement recommendations are provided for on-site parking and drive areas. Our pavement recommendations are based on pavement loading information provided by Greenberg Farrow Architects and presented in the “Project Understanding” section of this report and below. We recommend a PCC section be used in truck dock areas where truck jacks that support trailers are to be set and removed from the truck. The jacks will impose a long-term static point load to the area. The jack load should be treated as a column isolated load when considering PCC thickness and reinforcing. Our pavement recommendations are based on the following assumptions:  Standard-duty pavement loading consists of 50,000 18-kip ESALs based on a 10-year pavement design life and 3,500 vehicle passes per day.  Heavy-duty loading consists of 220,000 18-kip ESALs based on a 10-year pavement design life with 26 semi-trailer trucks per day.  The top 12 inches of soil subgrade below the pavement section is compacted to at least 95 percent of its maximum density per ASTM D 1557 or observations indicate that it is in a firm and unyielding condition.  A resilient modulus of 4,000 psi was estimated for the undocumented fill subgrade.  A resilient modulus of 20,000 psi was estimated for base rock.  Initial and terminal serviceability indices of 4.2 and 2.5, respectively.  Reliability and standard deviations of 75 percent and 0.45, respectively.  Structural coefficients of 0.42 and 0.10 for the asphalt and base rock, respectively. The PCC pavement sections were calculated using an assumed concrete flexural strength of 600 psi. Recommended pavement section thicknesses are presented in Table 4. 18 Greenberg-3-04:120214 Table 4. Pavement Section Thickness Class AC Thickness (inches) Aggregate Base Thickness (inches) PCC Thickness (inches) Aggregate Base Thickness (inches) Standard Duty 3.5 8 6.0 10.0 Heavy Duty 4.5 9 7.0 10.0 It is possible to leave the existing asphalt pavement section in place to be used as a working surface during site preparation. This includes the asphalt and aggregate base. After site preparation is complete, we recommend that the existing asphalt section be demolished, removed, and replaced with the sections recommended above. The pavement sections above are formulated for a minimum pavement thickness to mitigate potential damage frost heave. In PCC pavements, joints are typically spaced at 12-foot intervals to control cracking. Thickened edges should be used. Dowel bars used as load transfer should be 7/8-inch in diameter, 18 inches long, and at 12-inch spacing. The aggregate base should conform to WSS 9-03 - Aggregates, with the addition that the material not contain more than 5 percent by dry weight passing the U.S. Standard No. 200 Sieve. Aggregate base should be placed in one lift and compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D 1557. The AC pavement should conform to WSS 5-04 – Hot Mix Asphalt. AC should consist of ½-inch hot mix asphalt. The asphalt cement binder should be PG 64-22 Performance Grade Asphalt Cement conforming to WSS 9-02.1(4) – Performance Graded Asphalt Binder. The lift thickness should be 2.0 to 3.5 inches. The job mix formula should meet the requirements of WSS 5-04 – Hot Mix Asphalt and WSS 9-03.8 – Aggregates for Hot Mix Asphalt and be compacted to 91 percent of the maximum specific gravity of the mix or as required by the local jurisdiction in public right-of-way areas. Construction traffic should be limited to non-building unpaved portions of the site or haul roads. Construction traffic should not be allowed on new pavements. If construction traffic is to be allowed on newly constructed road sections, an allowance for this additional traffic will need to be made in the design pavement section. 11.0 RETAINING STRUCTURES 11.1 ASSUMPTIONS While we are not aware of significant retaining walls at the site, we provide the following general recommendations. The design pressures provided can general be used to design embedded walls for the egress tunnel. Our retaining wall design recommendations are based on the following assumptions: (1) the walls consist of conventional, cantilevered retaining walls, (2) conventional walls are less than 10 feet in height, (3) the backfill is drained, and (4) the backfill has a slope flatter than 4H:1V. Re-evaluation of our recommendations will be required if the retaining wall design criteria for the project varies from these assumptions. We can provide pressure recommendations for a specific wall depth and location configuration when this 19 Greenberg-3-04:120214 information is developed. At the time of this report a concept for an egress tunnel was presented, but specific depth and relative location to loads from the structure was not specified. 11.2 WALL DESIGN PARAMETERS Unrestrained site walls that retain native soil should be designed to resist active earth pressures of 35 to 55 pcf when supporting slopes between 4H:1V and 2H:1V, respectively. Where retained slopes are between inclinations of 4H:1V and 2H:1V, the designer may linearly interpolate between these active earth pressures. For the embedded building walls, a superimposed seismic lateral force should be calculated based on a dynamic force of 6H2 pounds per lineal foot of wall, where H is the height of the wall in feet, and applied at 0.6H from the base of the wall. If retaining walls are restrained from rotation prior to being backfilled, the aforementioned active earth pressures shall be increased by 15 pcf. Walls that extend below the level of groundwater should account for hydrostatic pressures. If other surcharges (e.g., slopes steeper than 2H:1V, foundations, vehicles, etc.) are located within a horizontal distance from the back of a wall equal to twice the height of the wall, then additional pressures may need to be accounted for in the wall design. Our office should be contacted for appropriate wall surcharges based on the actual magnitude and configuration of the applied loads. The wall footings should be designed in accordance with the guidelines provided in the appropriate portion of the “Shallow Foundations” section of this report. 11.3 WALL DRAINAGE AND BACKFILL The above design parameters have been provided assuming that back-of-wall drains will be installed to prevent buildup of hydrostatic pressures behind all walls and base of walls do not extend below static water levels. If a drainage system is not installed, then our office should be contacted for revised design forces. The backfill material placed behind the walls and extending a horizontal distance of ½H, where H is the height of the retaining wall, should consist of retaining wall select backfill placed and compacted in conformance with the “Structural Fill” section of this report. A minimum 6-inch-diameter perforated collector pipe should be placed at the base of the walls. The pipe should be embedded in a minimum 2-foot-wide zone of angular drain rock that is wrapped in a drainage geotextile fabric and extends up the back of the wall to within 1 foot of the finished grade. The drain rock and drainage geotextile fabric should meet specifications provided in the “Structural Fill” section of this report. The perforated collector pipes should discharge at an appropriate location away from the base of the wall. The discharge pipe(s) should not be tied directly into stormwater drain systems, unless measures are taken to prevent backflow into the wall’s drainage system. 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 construction of flatwork adjacent to retaining walls be postponed at least four weeks after backfilling of the wall, unless survey data indicates that settlement is complete prior to that time. 20 Greenberg-3-04:120214 12.0 OBSERVATION OF CONSTRUCTION Satisfactory foundation and earthwork performance depends to a large degree on quality of construction. Sufficient observation of the contractor's activities is a key part of determining that the work is completed in accordance with the construction drawings and specifications. Subsurface conditions observed during construction should be compared with those encountered during the subsurface exploration. Recognition of changed conditions often requires experience; therefore, qualified personnel should visit the site with sufficient frequency to detect if subsurface conditions change significantly from those anticipated. We recommend that GeoDesign be retained to observe earthwork activities, including stripping, proofrolling of the subgrade and repair of soft areas, footing subgrade preparation, performing laboratory compaction and field moisture-density tests, observing final proofrolling of the pavement subgrade and base rock, and asphalt placement and compaction. 13.0 LIMITATIONS We have prepared this preliminary geotechnical report for use by Greenberg Farrow Architects and members of the design and construction team for the proposed development. The data and report can be used for estimating purposes, but our report, conclusions, and interpretations should not be construed as a warranty of the subsurface conditions and are not applicable to other sites. Soil explorations indicate soil conditions only at specific locations and only to the depths penetrated. They do not necessarily reflect soil strata or water level variations that may exist between exploration locations. If subsurface conditions differing from those described are noted during the course of excavation and construction, re-evaluation will be necessary. The site development plans and design details were not finalized at the time this report was prepared. When the design has been finalized and if there are changes in the site grades or location, configuration, design loads or type of construction for the buildings, the conclusions and recommendations presented may not be applicable. If design changes are made, we should be retained to review our conclusions and recommendations and to provide a written evaluation or modification. The scope of our services does not include services related to construction safety precautions, and our recommendations are not intended to direct the contractor's methods, techniques, sequences or procedures, except as specifically described in our report for consideration in design. Within the limitations of scope, schedule, and budget, our services have been executed in accordance with the generally accepted practices in this area at the time this report was prepared. No warranty or other conditions, express or implied, should be understood.    21 Greenberg-3-04:120214 We appreciate the opportunity to be of continued service to you. Please call if you have questions concerning this report or if we can provide additional services. Sincerely, GeoDesign, Inc. Scott P. McDevitt, P.E. Project Engineer Julio C. Vela, Ph.D., P.E. Principal Engineer Signed 12/02/2014 22 Greenberg-3-04:120214 REFERENCES Mullineaux, D.R., Geologic Map of the Renton Quadrangle, King County, Washington, United States FIGURES SITE 0 (SCALE IN APPROXIMATE FEET) N 2000 4000VICINITY MAP BASED ON AERIAL PHOTOGRAPH OBTAINED FROM *22*/(($57+352Š Off 503.385.8439 Fax 503.968.3068 Salem OR 97302 350 Mission Street SE - Suite 102 Pr i n t e d B y : m m i l l e r | P r i n t D a t e : 1 2 / 2 / 2 0 1 4 1 1 : 1 9 : 3 2 A M Fi l e N a m e : J : \ E - L \ G r e e n b e r g \ G r e e n b e r g - 3 \ G r e e n b e r g - 3 - 0 4 \ F i g u r e s \ C A D \ G r e e n b e r g - 3 - 0 4 - V M 0 1 . d w g | L a y o u t : F I G U R E 1 VICINITY MAP COMMERCIAL WAREHOUSE BUILDING RENTON, WA GREENBERG-3-04 DECEMBER 2014 FIGURE 1 B-1CPT-1 S W 4 1 S T S T R E E T S 1 8 0 S T R E E T LIND AVENUE SW B - 3 B - 7 B - 8 B-5B-4 B - 2 B - 1 2 B - 1 1 B - 1 0 B - 9 B - 6 CPT-3CPT-5 C P T - 6 C P T - 4 CPT-8 C P T - 7 CPT-2 S I T E P L A N B A S E D O N A E R I A L P H O T O G R A P H 2 % 7 $ , 1 ( '  ) 5 2 0  * 2 2 * / (  ( $ 5 7 +  3 5 2 Š  M A R C H 6 , 2 0 1 3 LEGEND:BORINGCONE PENETROMETERMARCH 2013 EXPLORATION (GREENBERG-3-01) 0 ( S C A L E I N F E E T ) N 1 2 0 2 4 0 B-3CPT-1B-1Printed By: mmiller | Print Date: 12/2/2014 11:19:45 AM Off 503.385.8426 Fax 503.968.3068 Salem OR 97302 350 Mission Street - Suite 102 File Name: J:\E-L\Greenberg\Greenberg-3\Greenberg-3-04\Figures\CAD\Greenberg-3-04-SP02.dwg | Layout: FIGURE 2 SITE PLAN COMMERCIAL WAREHOUSE BUILDING RENTON, WA GREENBERG-3-04 DECEMBER 2014 FIGURE 2 S L A B W A L L H E I G H T E M B E D M E N T D E P T H W A T E R L E V E L B E H I N D W A L L 5 5 P C F 2 6 P C F 6 2 . 4 P C F + + S E I S M I C P R E S S U R E P E R R E P O R T C O M P L E T E L Y W A T E R P R O O F E D A L L A R O U N D P R E S S U R E F R O M S O I L S B E H I N D W A L L P R E S S U R E F R O M S T A T I C W A T E R L E V E L P r i n t e d B y : m m i l l e r | P r i n t D a t e : 1 2 / 2 / 2 0 1 4 1 1 : 1 9 : 5 2 A M F i l e N a m e : J : \ E - L \ G r e e n b e r g \ G r e e n b e r g - 3 \ G r e e n b e r g - 3 - 0 4 \ F i g u r e s \ C A D \ G r e e n b e r g - 3 - 0 4 - D E T 0 1 . d w g | L a y o u t : F I G U R E 3 O f f 5 0 3 . 3 8 5 . 8 4 3 9 F a x 5 0 3 . 9 6 8 . 3 0 6 8 S a l e m O R 9 7 3 0 2 3 5 0 M i s s i o n S t r e e t S E - S u i t e 1 0 2 E A R T H P R E S S U R E B E H I N D R E T A I N I N G W A L L S ( S O I L + W A T E R + S E I S M I C ) F I G U R E 3 G R E E N B E R G - 3 - 0 4 D E C E M B E R 2 0 1 4 C O M M E R C I A L W A R E H O U S E B U I L D I N G R E N T O N , W A N O T E S : 1 . F I G U R E S H O U L D B E U S E D I N C O N J U N C T I O N W I T H R E P O R T T E X T . 2 . E A R T H P R E S S U R E S A R E U N F A C T O R E D . 3 . F I G U R E D O E S N O T I N C L U D E L A T E R A L E A R T H P R E S S U R E I N D U C E D B Y S U R R O U N D I N G L O A D S . 4 . S U R C H A R G E E F F E C T S F R O M T R A F F I C , C O N S T R U C T I O N E Q U I P M E N T , S T O C K P I L E D S O I L , E T C . , S H O U L D B E A D D E D T O T H E A B O V E D E S I G N P R E S S U R E S . N O T T O S C A L E 1 . 2 8 m 2 n 2 ( m 2 + n 2 ) 2 0 . 2 n ( 0 . 1 6 + n 2 ) 2 h H Q L h = F O R m < 0 . 4 = F O R m > 0 . 4 = H Q L = h = 2 q ( - S I N C O S 2 ) 3 . 1 4 ( I N R A D I A N S ) h H 2 F O R m > 0 . 4 = F O R m < 0 . 4 = = h h ' = C O S 2 ( 1 . 1 ) S T R I P L O A D P A R A L L E L T O W A L L L I N E L O A D P A R A L L E L T O W A L L V E R T I C A L P O I N T L O A D D I S T R I B U T I O N O F H O R I Z O N T A L P R E S S U R E S h h S T R I P L O A D , q / 2 h h ' R E T A I N I N G W A L L O R S H O R I N G E X C A V A T I O N B A S E G R O U N D S U R F A C E G R O U N D S U R F A C E G R O U N D S U R F A C E E X C A V A T I O N B A S E E X C A V A T I O N B A S E R E T A I N I N G W A L L O R S H O R I N G R E T A I N I N G W A L L O R S H O R I N G R E T A I N I N G W A L L O R S H O R I N G N O T E S : 1 . F I G U R E S H O U L D B E U S E D I N C O N J U N C T I O N W I T H R E P O R T T E X T . 2 . T H E S E G U I D E L I N E S A P P L Y T O R I G I D W A L L S W I T H P O I S S O N ' S R A T I O A S S U M E D T O B E 0 . 5 F O R B A C K F I L L M A T E R I A L S . 3 . L A T E R A L P R E S S U R E S F R O M A N Y C O M B I N A T I O N O F A B O V E L O A D S M A Y B E D E T E R M I N E D B Y T H E P R I N C I P L E O F S U P E R P O S I T I O N . H Z = n H X = m H P O I N T L O A D , Q p H H X = m H L I N E L O A D , Q L X = m H Q P 0 . 2 8 n 2 ( 0 . 1 6 + n 2 ) 3 H 2 = h Q P ( m 2 + n 2 ) 3 1 . 7 7 m 2 n 2 N O T T O S C A L E P r i n t e d B y : m m i l l e r | P r i n t D a t e : 1 2 / 2 / 2 0 1 4 1 1 : 2 8 : 5 4 A M F i l e N a m e : J : \ E - L \ G r e e n b e r g \ G r e e n b e r g - 3 \ G r e e n b e r g - 3 - 0 4 \ F i g u r e s \ C A D \ G r e e n b e r g - 3 - 0 4 - D E T 0 2 . d w g | L a y o u t : F I G U R E 4 O f f 5 0 3 . 3 8 5 . 8 4 3 9 F a x 5 0 3 . 9 6 8 . 3 0 6 8 S a l e m O R 9 7 3 0 2 3 5 0 M i s s i o n S t r e e t S E - S u i t e 1 0 2 S U R C H A R G E - I N D U C E D L A T E R A L E A R T H P R E S S U R E S F I G U R E 4 G R E E N B E R G - 3 - 0 4 D E C E M B E R 2 0 1 4 C O M M E R C I A L W A R E H O U S E B U I L D I N G R E N T O N , W A APPENDIX A A-1 Greenberg-3-04:120214 APPENDIX A FIELD EXPLORATIONS GENERAL We explored subsurface conditions by completing twelve borings (B-1 through B-12) to depths of 11.5 to 111.5 feet BGS and eight CPT probes (CPT-1 through CPT-8) to depths of approximately 90 feet BGS. Borings were conducted by Western States Soil Conservation, Inc. of Aurora, Oregon, using mud rotary methods on February 18 and 19, 2013 and July 22 through 24, 2014. CPT services were provided by In Situ Engineering of Snohomish, Washington, on February 18, 2013 and Oregon Geotechnical Explorations, Inc. of Keizer, Oregon, on July 22 through 24, 2014 and are summarized in Appendix B. Figure 2 shows the approximate exploration locations relative to proposed site features. A member of our geotechnical staff observed the borings. We obtained representative samples of the various soil encountered in the explorations for geotechnical laboratory testing. Classifications and sampling intervals are presented on the exploration logs included in this appendix. SOIL SAMPLING Samples were obtained from the borings using a 1½-inch-inside diameter, split-spoon sampler in general accordance with ASTM D 1586. The split-spoon samplers were driven into the soil with a 140-pound hammer free-falling 30 inches. The samplers were driven a total distance of 18 inches. The number of blows required to drive the sampler the final 12 inches is recorded on the exploration logs, unless otherwise noted. Relatively undisturbed samples were obtained by advancing a Shelby tube in general accordance with ASTM D 1587 (the Standard Practice for Thin-walled Tube Sampling of Soils). SOIL CLASSIFICATION The soil samples were classified in accordance with the “Exploration Key” (Table A-1) and “Soil Classification System” (Table A-2), which are included in this appendix. The exploration logs indicate the depths at which the soil or its characteristics change, although the change actually could be gradual. If the change occurred between sample locations, the depth was interpreted. Classifications and sampling intervals are presented on the exploration logs included in this appendix. LABORATORY TESTING CLASSIFICATION The soil samples were classified in the laboratory to confirm field classifications. The laboratory classifications are presented on the exploration logs if those classifications differed from the field classifications. A-2 Greenberg-3-04:120214 MOISTURE CONTENT DETERMINATION We determined the natural moisture content of selected soil samples in general accordance with ASTM D 2216. The natural moisture content is a ratio of the weight of the water to soil in a test sample and is expressed as a percentage. The test results are included on the exploration logs presented in this appendix. ATTERBERG LIMIT TESTING The plastic limit and liquid limit (Atterberg limits) of selected soil samples were determined in accordance with ASTM D 4318. The Atterberg limits and the plasticity index were completed to aid in the classification of the soil. The plastic limit is defined as the moisture content (in percent) where the soil becomes brittle. The liquid limit is defined as the moisture content where the soil begins to act similar to a liquid. The plasticity index is the difference between the liquid and plastic limits. The test results are presented on the exploration logs included in this appendix and Figure A-13. PARTICLE-SIZE ANALYSIS Particle-size analyses were performed on selected samples in general accordance with ASTM D 422 (hydrometer test) and ASTM D 1140 (percent of material finer than the U.S. Standard No. 200 Sieve). The test results are presented on the exploration logs included in this appendix and Figure A-14. SYMBOL SAMPLING DESCRIPTION Location of sample obtained in general accordance with ASTM D 1586 Standard Penetration Test with recovery Location of sample obtained using thin-wall Shelby tube or Geoprobe® sampler in general accordance with ASTM D 1587 with recovery Location of sample obtained using Dames & Moore sampler and 300-pound hammer or pushed with recovery Location of sample obtained using Dames & Moore and 140-pound hammer or pushed with recovery Location of sample obtained using 3-inch-O.D. California split-spoon sampler and 140-pound hammer Location of grab sample Rock coring interval Water level during drilling Water level taken on date shown GEOTECHNICAL TESTING EXPLANATIONS ATT CBR CON DD DS HYD MC MD OC P Atterberg Limits California Bearing Ratio Consolidation Dry Density Direct Shear Hydrometer Gradation Moisture Content Moisture-Density Relationship Organic Content Pushed Sample PP P200 RES SIEV TOR UC VS kPa Pocket Penetrometer Percent Passing U.S. Standard No. 200 Sieve Resilient Modulus Sieve Gradation Torvane Unconfined Compressive Strength Vane Shear Kilopascal ENVIRONMENTAL TESTING EXPLANATIONS CA P PID ppm Sample Submitted for Chemical Analysis Pushed Sample Photoionization Detector Headspace Analysis Parts per Million ND NS SS MS HS Not Detected No Visible Sheen Slight Sheen Moderate Sheen Heavy Sheen 350 Mission Street SE - Suite 102 Salem OR 97302 Off 503.385.8439 Fax 503.968.3068 EXPLORATION KEY TABLE A-1 Graphic Log of Soil and Rock Types Inferred contact between soil or rock units (at approximate depths indicated) Observed contact between soil or rock units (at depth indicated) RELATIVE DENSITY - COARSE-GRAINED SOILS Relative Density Standard Penetration Resistance Dames & Moore Sampler (140-pound hammer) Dames & Moore Sampler (300-pound hammer) Very Loose 0 – 4 0 - 11 0 - 4 Loose 4 – 10 11 - 26 4 - 10 Medium Dense 10 – 30 26 - 74 10 - 30 Dense 30 – 50 74 - 120 30 - 47 Very Dense More than 50 More than 120 More than 47 CONSISTENCY - FINE-GRAINED SOILS Consistency Standard Penetration Resistance Dames & Moore Sampler (140-pound hammer) Dames & Moore Sampler (300-pound hammer) Unconfined Compressive Strength (tsf) Very Soft Less than 2 Less than 3 Less than 2 Less than 0.25 Soft 2 - 4 3 – 6 2 - 5 0.25 - 0.50 Medium Stiff 4 - 8 6 – 12 5 - 9 0.50 - 1.0 Stiff 8 - 15 12 – 25 9 - 19 1.0 - 2.0 Very Stiff 15 - 30 25 – 65 19 – 31 2.0 - 4.0 Hard More than 30 More than 65 More than 31 More than 4.0 PRIMARY SOIL DIVISIONS GROUP SYMBOL GROUP NAME COARSE-GRAINED SOILS (more than 50% retained on No. 200 sieve) GRAVEL (more than 50% of coarse fraction retained on No. 4 sieve) CLEAN GRAVELS (< 5% fines) GW or GP GRAVEL GRAVEL WITH FINES (≥ 5% and ≤ 12% fines) GW-GM or GP-GM GRAVEL with silt GW-GC or GP-GC GRAVEL with clay GRAVELS WITH FINES (> 12% fines) GM silty GRAVEL GC clayey GRAVEL GC-GM silty, clayey GRAVEL SAND (50% or more of coarse fraction passing No. 4 sieve) CLEAN SANDS (<5% fines) SW or SP SAND SANDS WITH FINES (≥ 5% and ≤ 12% fines) SW-SM or SP-SM SAND with silt SW-SC or SP-SC SAND with clay SANDS WITH FINES (> 12% fines) SM silty SAND SC clayey SAND SC-SM silty, clayey SAND FINE-GRAINED SOILS (50% or more passing No. 200 sieve) SILT AND CLAY Liquid limit less than 50 ML SILT CL CLAY CL-ML silty CLAY OL ORGANIC SILT or ORGANIC CLAY Liquid limit 50 or greater MH SILT CH CLAY OH ORGANIC SILT or ORGANIC CLAY HIGHLY ORGANIC SOILS PT PEAT MOISTURE CLASSIFICATION ADDITIONAL CONSTITUENTS Term Field Test Secondary granular components or other materials such as organics, man-made debris, etc. Percent Silt and Clay In: Percent Sand and Gravel In: dry very low moisture, dry to touch Fine-Grained Soils Coarse- Grained Soils Fine-Grained Soils Coarse- Grained Soils moist damp, without visible moisture < 5 trace trace < 5 trace trace 5 – 12 minor with 5 – 15 minor minor wet visible free water, usually saturated > 12 some silty/clayey 15 – 30 with with > 30 sandy/gravelly Indicate % 350 Mission Street SE - Suite 102 Salem OR 97302 Off 503.385.8439 Fax 503.968.3068 SOIL CLASSIFICATION SYSTEM TABLE A-2 LL = 67%PL = 38% P200 = 15% P200 = 87% P P P 0.3 4.0 13.0 20.0 28.0 33.0 ATT HYDSIEV P200 P200 ASPHALT CONCRETE (3 inches). Medium dense, gray SAND with gravel(SP); moist, fine to medium, gravel isfine - FILL. Medium stiff, gray SILT (MH), some clay,trace sand; moist, sand is fine. Soft, gray SILT (ML) minor sand; moist, sand is fine. Medium dense, black-gray, silty SAND (SM); moist, fine. becomes loose; interbedded with medium stiff, gray silt, some sand at25.0 feet Soft, gray SILT (MH), minor sand; moist, sand is fine. Medium dense, gray, silty SAND (SM); moist, fine to medium. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-1 COMPLETED:02/18/13 EL E V A T I O N DE P T H SA M P L E FIGURE A-1 BORING BIT DIAMETER:5-inch RENTON, WA GREENBERG-3-01 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G DEPTHFEET LOGGED BY:TAP MARCH 2013350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 1 - B 1 _ 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 0 5 10 15 20 25 30 35 40 26 5 3 3 18 8 3 19 P200 = 88% P 45.0 50.0 P200 becomes dense at 40.0 feet Very stiff, gray SILT (MH), trace sand; moist, sand is fine. Very soft, dark gray SILT (MH), minor sand; moist, sand is fine. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-1 COMPLETED:02/18/13 EL E V A T I O N DE P T H SA M P L E FIGURE A-1 BORING BIT DIAMETER:5-inch RENTON, WA GREENBERG-3-01 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G (continued) DEPTHFEET LOGGED BY:TAP MARCH 2013350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 1 - B 1 _ 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 40 45 50 55 60 65 70 75 80 34 17 0 0 0 0 0 0 Surface elevation was notmeasured at the time ofexploration. 86.0 95.5 110.0 111.5 (continued from previous page) Very soft, gray, sandy SILT (MH); moist,sand is fine. grades to trace sand at 90.0 feet Medium dense, gray SAND with silt (SP- SM); moist, fine. grades to dense, trace silt at 100.0 feet Very dense, dark gray SAND (SP), minor silt; moist, fine to medium. Exploration completed at a depth of111.5 feet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-1 COMPLETED:02/18/13 EL E V A T I O N DE P T H SA M P L E FIGURE A-1 BORING BIT DIAMETER:5-inch RENTON, WA GREENBERG-3-01 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G (continued) DEPTHFEET LOGGED BY:TAP MARCH 2013350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 1 - B 1 _ 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 80 85 90 95 100 105 110 115 120 0 2 0 10 33 51 P200 = 6% P200 = 70% 0.3 4.5 8.5 9.5 33.0 HYDSIEV P200 P200 ASPHALT CONCRETE (3 inches). Medium dense, gray GRAVEL with sand(GP); moist, fine to coarse and angular,sand is coarse - FILL. Medium dense, gray SAND (SP), minorgravel; moist, fine to medium, gravel isfine to coarse and angular. becomes loose at 7.5 feet Soft, brown-gray SILT (MH), some clay;moist. Loose, black-gray SAND with silt (SP-SM), minor gravel; moist, fine tomedium, gravel is fine to coarse. becomes medium dense at 15.0 feet becomes dense at 25.0 feet Very soft, gray, sandy SILT (MH); moist, sand is fine. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-2 COMPLETED:02/19/13 EL E V A T I O N DE P T H SA M P L E FIGURE A-2 BORING BIT DIAMETER:5-inch RENTON, WA GREENBERG-3-01 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G DEPTHFEET LOGGED BY:TAP MARCH 2013350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 1 - B 1 _ 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 0 5 10 15 20 25 30 35 40 11 10 4 4 26 23 36 30 1 P200 = 85% P 41.5 44.0 P200 (continued from previous page) Medium dense, gray SAND (SP), tracesilt and gravel; moist, fine, gravel isfine. Very soft, dark gray SILT (MH), minorsand, trace clay; moist, sand is fine. grades to trace gravel; gravel is fine at 50.0 feet grades without gravel at 60.0 feet INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-2 COMPLETED:02/19/13 EL E V A T I O N DE P T H SA M P L E FIGURE A-2 BORING BIT DIAMETER:5-inch RENTON, WA GREENBERG-3-01 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G (continued) DEPTHFEET LOGGED BY:TAP MARCH 2013350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 1 - B 1 _ 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 40 45 50 55 60 65 70 75 80 15 1 2 1 0 0 Surface elevation was notmeasured at the time ofexploration. 111.0 111.5 (continued from previous page) Very dense, dark gray SAND (SP); moist,fine to medium. Exploration completed at a depth of111.5 feet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-2 COMPLETED:02/19/13 EL E V A T I O N DE P T H SA M P L E FIGURE A-2 BORING BIT DIAMETER:5-inch RENTON, WA GREENBERG-3-01 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G (continued) DEPTHFEET LOGGED BY:TAP MARCH 2013350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 1 - B 1 _ 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 80 85 90 95 100 105 110 115 120 0 0 61 61 P200 = 6% P 0.1 2.8 4.5 11.0 14.0 17.0 18.3 30.0 35.0 P200 ASPHALT CONCRETE (1.5 inches). Medium dense to dense, gray GRAVEL(GP), trace sand; moist, fine, sand isfine to medium - FILL. Medium dense, gray SAND with silt (SP- SM); moist, fine to medium. Soft, gray SILT (ML), minor organics;moist. Medium dense, black-gray SAND (SP);moist to wet, fine to medium. Medium dense, gray, silty SAND (SM);moist to wet, fine to medium. Very stiff, gray SILT (ML); moist. Medium dense, black-gray, silty SAND(SM); moist to wet, fine to medium. dense at 20.0 feet Dense, black-gray SAND with silt (SP- SM), trace gravel; moist to wet, fine tomedium, gravel is fine. Very soft, gray SILT (MH), trace gravel; moist, gravel is fine. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-3 COMPLETED:07/22/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-3 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 0 5 10 15 20 25 30 35 40 18 3 0 13 10 16 27 34 LL = 46%PL = 25% P200 = 95% ATT P200 (continued from previous page) INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-3 COMPLETED:07/22/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-3 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G (continued) DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 40 45 50 55 60 65 70 75 80 0 0 0 0 Surface elevation was notmeasured at the time ofexploration. 91.5 (continued from previous page) Exploration completed at a depth of91.5 feet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-3 COMPLETED:07/22/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-3 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G (continued) DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 80 85 90 95 100 105 110 115 120 0 0 Sample consisted entirely ofa single piece of wood thatwas cored by the sampler (alarge root or fallen tree). 0.2 2.0 10.3 25.0 ASPHALT CONCRETE (2.0 inches). Medium dense to dense, gray GRAVEL(GP); moist, fine - FILL. Very soft, gray SILT (ML), trace sand; moist, sand is fine. Medium dense, black-gray SAND (SP),trace silt; moist to wet, fine to medium. grades to fine at 12.5 feet wood fragment from 15.0 to 16.5 feet dense at 20.0 feet Very soft, gray SILT (MH); moist to wet. lens of black-gray SAND (SP); moist towet, fine to medium from 31.0 to 32.0 feet INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-4 COMPLETED:07/22/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-4 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 0 5 10 15 20 25 30 35 40 2 0 20 17 44 28 10 LL = 43%PL = 26% P200 = 84% 3-inch-thick interbed of sandat 60.5 feet. ATT P200 (continued from previous page) grades to soft, trace sand; sand is fine at 50.0 feet grades to very soft at 70.0 feet INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-4 COMPLETED:07/22/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-4 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G (continued) DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 40 45 50 55 60 65 70 75 80 0 3 2 0 Surface elevation was notmeasured at the time ofexploration. 91.5 (continued from previous page) Exploration completed at a depth of91.5 feet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-4 COMPLETED:07/22/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-4 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G (continued) DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 80 85 90 95 100 105 110 115 120 0 0 P 0.2 2.0 11.0 19.5 27.0 37.0 ASPHALT CONCRETE (2.0 inches). Medium dense to dense, gray GRAVEL(GP); moist, fine - FILL. Soft, gray and brown SILT with organics (ML); moist, organics are in thin lenses. Loose, black-gray SAND (SP), trace silt;moist to wet, fine to medium. grades to medium dense at 15.0 feet lens of medium stiff, gray SILT (ML); moist from 17.5 to 18.5 feet Very soft, gray SILT (MH), trace organics(roots); moist to wet. Interbedded:Medium dense, dark gray SAND with silt(SP-SM); moist, fine to medium and stiff, gray SILT (MH), trace sand; moist. Very soft, gray SILT (MH); moist to wet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-5 COMPLETED:07/23/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-5 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 0 5 10 15 20 25 30 35 40 2 2 5 16 15 2 13 (continued from previous page) INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-5 COMPLETED:07/23/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-5 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G (continued) DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 40 45 50 55 60 65 70 75 80 0 1 0 0 Surface elevation was notmeasured at the time ofexploration. 91.5 (continued from previous page) Exploration completed at a depth of91.5 feet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-5 COMPLETED:07/23/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-5 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G (continued) DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 80 85 90 95 100 105 110 115 120 0 0 P200 = 13% 0.2 2.0 4.5 8.0 26.5 P200 ASPHALT CONCRETE (2.0 inches). Medium dense to dense, gray GRAVEL(GP), trace silt and sand; moist to wet,fine - FILL. Medium dense, gray, silty SAND (SM); moist to wet, fine to medium. Medium stiff, brown and gray SILT withorganics (ML); moist. Medium dense, black-gray, silty SAND (SM), trace silt; moist to wet, fine to medium. Very soft, gray SILT (MH); moist to wet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-6 COMPLETED:07/23/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-6 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 0 5 10 15 20 25 30 35 40 14 6 15 19 22 21 30 (continued from previous page) INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-6 COMPLETED:07/23/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-6 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G (continued) DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 40 45 50 55 60 65 70 75 80 0 1 0 0 Surface elevation was notmeasured at the time ofexploration. 91.5 (continued from previous page) Exploration completed at a depth of91.5 feet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-6 COMPLETED:07/23/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-6 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G (continued) DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 80 85 90 95 100 105 110 115 120 0 0 Surface elevation was notmeasured at the time ofexploration. 0.3 2.5 5.0 8.5 11.3 11.5 ASPHALT CONCRETE (4.0 inches). Medium dense, gray GRAVEL with sand(GP); moist to wet, fine, sand is fine tocoarse - FILL. Interbedded: Loose, gray SAND with silt (SP-SM);moist to wet, fine to medium andmedium stiff, gray and brown SILT (ML), minor sand; moist to wet. Soft, gray and brown SILT (ML), minorsand, trace gravel; moist, sand is fine,gravel is fine. Medium dense, black-gray SAND (SP), trace silt; moist to wet, fine to medium. Medium dense, gray, silty SAND (SM);moist to wet, fine to medium. Exploration completed at a depth of 11.5 feet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-7 COMPLETED:07/24/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-7 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 0 5 10 15 20 25 30 35 40 6 2 10 11 Surface elevation was notmeasured at the time ofexploration. 0.3 3.0 8.8 11.5 ASPHALT CONCRETE (4.0 inches). Medium dense, gray GRAVEL with sand(GP); moist to wet, fine, sand is fine tocoarse - FILL. Soft, gray and brown SILT with organics (ML); moist to wet. Medium dense, black-gray SAND (SP);moist to wet, fine to medium. Exploration completed at a depth of11.5 feet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-8 COMPLETED:07/24/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-8 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 0 5 10 15 20 25 30 35 40 16 3 9 22 LL = 72%PL = 40% Surface elevation was notmeasured at the time ofexploration. 0.4 3.5 7.0 11.0 11.5 ATT ASPHALT CONCRETE (5.0 inches). Medium dense, gray GRAVEL with sand(GP); moist to wet, fine, sand is fine tocoarse - FILL. Very soft, gray and brown SILT withorganics (ML); moist to wet. Loose, gray, silty SAND (SM); moist towet, fine to medium. Medium dense, black-gray SAND (SP),minor gravel, trace silt; moist to wet, fine to medium, gravel is fine. Exploration completed at a depth of11.5 feet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-9 COMPLETED:07/24/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-9 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 0 5 10 15 20 25 30 35 40 11 0 5 13 Surface elevation was notmeasured at the time ofexploration. 0.4 2.5 7.8 11.5 ASPHALT CONCRETE (5.0 inches). Medium dense to dense, gray GRAVELwith sand (GP); moist to wet, fine, sandis fine to coarse - FILL. Stiff, gray-brown SILT (ML), trace sand; moist. very soft, with organics at 5.0 feet Loose, black-gray SAND (SP), trace silt;moist to wet, fine to medium. medium dense at 10.0 feet Exploration completed at a depth of11.5 feet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-10 COMPLETED:07/24/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-10 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 0 5 10 15 20 25 30 35 40 9 2 9 12 Surface elevation was notmeasured at the time ofexploration. 0.3 3.0 10.5 11.5 ASPHALT CONCRETE (3.5 inches). Loose, gray GRAVEL with sand (GP);moist to wet, fine, fine, sand is fine tocoarse - FILL. Stiff, gray and brown SILT (ML); moist. very soft, with organics at 5.0 feet Loose, black-gray SAND (SP), trace silt; moist to wet, fine to medium. Exploration completed at a depth of11.5 feet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-11 COMPLETED:07/24/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-11 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 0 5 10 15 20 25 30 35 40 10 2 3 9 Surface elevation was notmeasured at the time ofexploration. 0.3 3.0 8.5 11.5 ASPHALT CONCRETE (depth not recorded). Medium dense, gray GRAVEL with sand(GP); moist to wet, fine, sand is fine to coarse - FILL. Very soft, gray and brown SILT withorganics (ML); moist to wet. Loose, black-gray SAND (SP), trace silt;moist to wet, fine to medium. Exploration completed at a depth of11.5 feet. INSTALLATION AND COMMENTS MOISTURE CONTENT % CORE REC%RQD% BLOW COUNT BORING B-12 COMPLETED:07/24/14 EL E V A T I O N DE P T H SA M P L E FIGURE A-12 BORING BIT DIAMETER:4 7/8-inch RENTON, WA GREENBERG-3-04 COMMERCIAL WAREHOUSE BUILDING GR A P H I C L O G MATERIAL DESCRIPTION TE S T I N G DEPTHFEET LOGGED BY:TAP DECEMBER 2014350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 BORING METHOD:mud rotary (see report text) DRILLED BY:Western States Soil Conservation, Inc. BO R I N G L O G G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 50 100 0 50 100 0 5 10 15 20 25 30 35 40 6 2 10 7 0 10 20 30 40 50 60 MH or OH ML or OL 0 10 20 30 40 50 60 70 80 90 100 110 CL-ML CL or OL ATTERBERG LIMITS TEST RESULTS CH or OH "A" LINE LIQUID LIMIT PL A S T I C I T Y I N D E X GREENBERG-3-01 MARCH 2013 COMMERCIAL WAREHOUSE BUILDING RENTON, WA FIGURE A-13A350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 MOISTURE CONTENT(PERCENT) 5.0 66 EXPLORATIONNUMBER SAMPLE DEPTH(FEET) 296738B-1 KEY LIQUID LIMIT PLASTIC LIMIT PLASTICITY INDEX AT T E R B E R G _ L I M I T S 7 G R E E N B E R G - 3 - 0 1 - B 1 _ 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 10 20 30 40 50 60 MH or OH ML or OL 0 10 20 30 40 50 60 70 80 90 100 110 CL-ML CL or OL ATTERBERG LIMITS TEST RESULTS CH or OH "A" LINE LIQUID LIMIT PL A S T I C I T Y I N D E X GREENBERG-3-04 DECEMBER 2014 COMMERCIAL WAREHOUSE BUILDING RENTON, WA FIGURE A-13B350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 MOISTURE CONTENT(PERCENT) 40.0 40.0 5.0 52 41 90 EXPLORATIONNUMBER SAMPLE DEPTH(FEET) 21 17 32 46 43 72 25 26 40 B-3 B-4 B-9 KEY LIQUID LIMIT PLASTIC LIMIT PLASTICITY INDEX AT T E R B E R G _ L I M I T S 7 G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.11101001,000 COARSE FINESBOULDERS D10 COARSE GRAIN SIZE IN MILLIMETERS PE R C E N T F I N E R B Y W E I G H T SAND (PERCENT) 17.0 10.0 SILT D60 3/4"40 8 88 17 2 60 MEDIUM GRAVEL (PERCENT) FINE 4 10 20 0 8 D30MOISTURE CONTENT (PERCENT)D5 0.00 0.13 0.08 SAMPLE DEPTH (FEET) U.S. STANDARD SIEVE NUMBERS 3" FINECOBBLES CLAY (PERCENT)D50 3/8" CLAY EXPLORATION NUMBER 1 1/2" SILT (PERCENT)KEY 76 3 GRAIN-SIZE TEST RESULTS 100 200 SANDGRAVEL 47 27 0.03 0.59 0.02 0.47 0.01 0.31 B-1 B-2 FIGURE A-14COMMERCIAL WAREHOUSE BUILDING RENTON, WA GREENBERG-3-01 MARCH 2013350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 GRAIN SIZE NO P200 GREENBERG-3-01-B1_2.GPJ GEODESIGN.GDT PRINT DATE: 12/2/14:KT B-1 5.0 66 67 38 29 B-1 9.0 60 B-1 17.0 49 0 8 92 B-1 20.0 28 15 B-1 30.0 46 87 B-1 40.0 30 B-1 50.0 47 88 B-1 65.0 54 B-2 5.0 16 B-2 7.5 24 B-2 10.0 28 8 88 5 B-2 15.0 27 6 B-2 25.0 19 B-2 35.0 41 70 B-2 45.0 42 85 B-2 55.0 43 B-2 70.0 53 GRAVEL (PERCENT) SAMPLE DEPTH(FEET) SUMMARY OF LABORATORY DATA ELEVATION (FEET) P200 (PERCENT) SIEVE PLASTICLIMIT PLASTICITYINDEX ATTERBERG LIMITSMOISTURECONTENT (PERCENT) SAMPLE INFORMATION EXPLORATION NUMBER SAND (PERCENT) DRYDENSITY (PCF)LIQUIDLIMIT GREENBERG-3-01 MARCH 2013 COMMERCIAL WAREHOUSE BUILDING RENTON, WA FIGURE A-15A350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 LA B S U M M A R Y G R E E N B E R G - 3 - 0 1 - B 1 _ 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T B-3 2.5 17 B-3 5.0 81 B-3 7.5 69 B-3 15.0 32 B-3 20.0 24 B-3 30.0 26 6 B-3 40.0 52 46 25 21 B-3 50.0 45 B-3 60.0 56 95 B-3 70.0 54 B-4 5.0 52 B-4 7.5 55 B-4 10.0 25 B-4 15.0 198 B-4 40.0 40 43 26 17 B-4 50.0 39 84 B-5 5.0 59 B-5 10.0 96 B-5 17.5 37 B-5 30.0 39 B-5 40.0 47 B-5 60.0 45 B-6 2.5 17 B-6 5.0 75 B-6 10.0 32 13 B-6 17.5 26 B-6 20.0 25 GRAVEL (PERCENT) SAMPLE DEPTH(FEET) SUMMARY OF LABORATORY DATA ELEVATION (FEET) P200 (PERCENT) SIEVE PLASTICLIMIT PLASTICITYINDEX ATTERBERG LIMITSMOISTURECONTENT (PERCENT) SAMPLE INFORMATION EXPLORATION NUMBER SAND (PERCENT) DRYDENSITY (PCF)LIQUIDLIMIT GREENBERG-3-04 DECEMBER 2014 COMMERCIAL WAREHOUSE BUILDING RENTON, WA FIGURE A-15B350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 LA B S U M M A R Y G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T B-6 30.0 18 B-6 50.0 36 B-6 70.0 54 B-7 2.5 22 B-7 5.0 49 B-7 7.5 70 B-8 2.5 19 B-8 5.0 114 B-8 7.5 42 B-9 2.5 21 B-9 5.0 90 72 40 32 B-9 7.5 43 B-10 2.5 25 B-10 5.0 102 B-10 7.5 48 B-11 2.5 23 B-11 5.0 104 B-11 10.0 35 B-12 2.5 25 B-12 5.0 62 GRAVEL (PERCENT) SAMPLE DEPTH(FEET) SUMMARY OF LABORATORY DATA ELEVATION (FEET) P200 (PERCENT) SIEVE PLASTICLIMIT PLASTICITYINDEX ATTERBERG LIMITSMOISTURECONTENT (PERCENT) SAMPLE INFORMATION EXPLORATION NUMBER SAND (PERCENT) DRYDENSITY (PCF)LIQUIDLIMIT GREENBERG-3-04 DECEMBER 2014 COMMERCIAL WAREHOUSE BUILDING RENTON, WA (continued) FIGURE A-15B350 Mission Street SE - Suite 102Salem OR 97302Off 503.385.8439 Fax 503.968.3068 LA B S U M M A R Y G R E E N B E R G - 3 - 0 4 - B 3 _ 1 2 . G P J G E O D E S I G N . G D T P R I N T D A T E : 1 2 / 2 / 1 4 : K T APPENDIX B B-1 Greenberg-3-04:120214 APPENDIX B CONE PENETROMETER TESTING Our subsurface exploration program included eight CPT probes (CPT-1 through CPT-8) to depths of approximately 90 feet BGS. Figure 2 shows the location of the CPT probes relative to existing proposed site features. The CPT is an in situ test that characterizes subsurface stratigraphy. The testing includes advancing a 35.6-millimeter-diameter cone and friction sleeve through the soil profile. The cone is advanced at a rate of approximately 2 centimeters per second. Tip resistance, sleeve friction, and pore pressure are typically recorded at 0.1 meter intervals. At selected depths, the cone advancement was suspended and pore-water dissipation rates measured. Shear wave velocity was measured at 1 meter intervals for a portion of CPT-1 and in CPT-4. This appendix presents the results of the CPT probes completed for this project. GeoDesign Inc. Operator: Gerdes Sounding: CPT-1 Cone Used: DDG1238 CPT Date/Time: 2/18/2013 11:31:03 AM Location: 601 SW 41 St Job Number: Greenberg-3-01 Maximum Depth = 90.06 feet Depth Increment = 0.164 feet InSitu Engineering Predrilled 1ft *Soil behavior type and SPT based on data from UBC-1983 Tip Resistance Qc TSF 30000 10 20 30 40 50 60 70 80 90 Depth(ft) Pore Pressure Pw PSI 120-20 Friction Ratio Fs/Qc (%) 50 Soil Behavior Type* Zone: UBC-1983 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) 120 SPT N* 60% Hammer 450 GeoDesign / CPT-2 / 601 SW 41st St. Renton Operator: OGE TAJ Sounding: CPT-2 Cone Used: DPG1211 CPT Date/Time: 7/24/2014 11:28:32 AM Location: GeoDesign/ CPT-2 / 601 SW 41st St Renton Job Number: OGE 14034CPT-2(021) Maximum Depth = 90.72 feet Depth Increment = 0.164 feet *Soil behavior type and SPT based on data from UBC-1983 Tip Resistance Qt TSF 3000 Local Friction Fs TSF 30 Pore Pressure Pw PSI 120-20 Friction Ratio Fs/Qt (%) 60 Soil Behavior Type* Zone: UBC-1983 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) 120 SPT N* 60% Hammer6000 10 20 30 40 50 60 70 80 90 100 Depth(ft) GeoDesign / CPT-3 / 601 SW 41st St. Renton Operator: OGE TAJ Sounding: CPT-3 Cone Used: DPG1211 CPT Date/Time: 7/22/2014 12:46:35 PM Location: GeoDesign/ CPT-3 / 601 SW 41st St Renton Job Number: OGE 14034CPT-3(021) Maximum Depth = 90.72 feet Depth Increment = 0.164 feet *Soil behavior type and SPT based on data from UBC-1983 Tip Resistance Qt TSF 3000 Local Friction Fs TSF 30 Pore Pressure Pw PSI 120-20 Friction Ratio Fs/Qt (%) 60 Soil Behavior Type* Zone: UBC-1983 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) 120 SPT N* 60% Hammer6000 10 20 30 40 50 60 70 80 90 100 Depth(ft) GeoDesign / CPT-4 / 601 SW 41st St. Renton Operator: OGE TAJ Sounding: CPT-4 Cone Used: DPG1211 CPT Date/Time: 7/23/2014 7:56:24 AM Location: GeoDesign/ CPT-4 / 601 SW 41st St Renton Job Number: OGE 14034CPT-4(021) Maximum Depth = 91.04 feet Depth Increment = 0.164 feet *Soil behavior type and SPT based on data from UBC-1983 Tip Resistance Qt TSF 3000 Local Friction Fs TSF 30 Pore Pressure Pw PSI 120-20 Friction Ratio Fs/Qt (%) 60 Soil Behavior Type* Zone: UBC-1983 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) 120 SPT N* 60% Hammer6000 10 20 30 40 50 60 70 80 90 100 Depth(ft) GeoDesign / CPT-5 / 601 SW 41st St. Renton Operator: OGE TAJ Sounding: CPT-5 Cone Used: DPG1211 CPT Date/Time: 7/23/2014 3:56:06 PM Location: GeoDesign/ CPT-5 / 601 SW 41st St Renton Job Number: OGE 14034CPT-5(021) Maximum Depth = 90.88 feet Depth Increment = 0.164 feet *Soil behavior type and SPT based on data from UBC-1983 Tip Resistance Qt TSF 3000 Local Friction Fs TSF 30 Pore Pressure Pw PSI 120-20 Friction Ratio Fs/Qt (%) 60 Soil Behavior Type* Zone: UBC-1983 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) 120 SPT N* 60% Hammer6000 10 20 30 40 50 60 70 80 90 100 Depth(ft) GeoDesign / CPT-6 / 601 SW 41st St. Renton Operator: OGE TAJ Sounding: CPT-6 Cone Used: DPG1211 CPT Date/Time: 7/24/2014 8:44:27 AM Location: GeoDesign/ CPT-6 / 601 SW 41st St Renton Job Number: OGE 14034CPT-6(021) Maximum Depth = 91.21 feet Depth Increment = 0.164 feet *Soil behavior type and SPT based on data from UBC-1983 Tip Resistance Qt TSF 3000 Local Friction Fs TSF 30 Pore Pressure Pw PSI 120-20 Friction Ratio Fs/Qt (%) 60 Soil Behavior Type* Zone: UBC-1983 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) 120 SPT N* 60% Hammer6000 10 20 30 40 50 60 70 80 90 100 Depth(ft) GeoDesign / CPT-7 / 601 SW 41st St. Renton Operator: OGE TAJ Sounding: CPT-7 Cone Used: DPG1211 CPT Date/Time: 7/23/2014 10:18:36 AM Location: GeoDesign/ CPT-7 / 601 SW 41st St Renton Job Number: OGE 14034CPT-7(021) Maximum Depth = 90.72 feet Depth Increment = 0.164 feet *Soil behavior type and SPT based on data from UBC-1983 Tip Resistance Qt TSF 3000 Local Friction Fs TSF 30 Pore Pressure Pw PSI 120-20 Friction Ratio Fs/Qt (%) 60 Soil Behavior Type* Zone: UBC-1983 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) 120 SPT N* 60% Hammer6000 10 20 30 40 50 60 70 80 90 100 Depth(ft) GeoDesign / CPT-8 / 601 SW 41st St. Renton Operator: OGE TAJ Sounding: CPT-8 Cone Used: DPG1211 CPT Date/Time: 7/23/2014 1:24:28 PM Location: GeoDesign/ CPT-8 / 601 SW 41st St Renton Job Number: OGE 14034CPT-8(021) Maximum Depth = 91.04 feet Depth Increment = 0.164 feet *Soil behavior type and SPT based on data from UBC-1983 Tip Resistance Qt TSF 3000 Local Friction Fs TSF 30 Pore Pressure Pw PSI 120-20 Friction Ratio Fs/Qt (%) 60 Soil Behavior Type* Zone: UBC-1983 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) 120 SPT N* 60% Hammer6000 10 20 30 40 50 60 70 80 90 100 Depth(ft) ACRONYMS Greenberg-3-04:120214 ACRONYMS AC asphalt concrete AOS apparent opening size ASCE American Society of Civil Engineers ASTM American Society for Testing and Materials BGS below ground surface CPT cone penetration test ESAL equivalent single-axle load fps feet per second g gravitational acceleration (32.2 feet/second2) H:V horizontal to vertical IBC International Building Code MCE maximum considered earthquake OSHA Occupational Safety and Health Administration PCC portland cement concrete pcf pounds per cubic foot PGA peak ground acceleration psf pounds per square foot psi pounds per square inch SPT standard penetration test WSS Washington Standard Specifications for Road, Bridge, and Municipal Construction (2014) Memorandum Page 1 of 9 350 Mission Street SE, Suite 102 l Salem, OR 97302 l 503.968.8787 To: Frank Coda From: Julio C. Vela, Ph.D., P.E. and Scott P. McDevitt, P.E. Company: Greenberg Farrow Architects Date: February 3, 2015 Address: 19000 MacArthur Boulevard, Suite 250 Irvine, CA 92612 cc: Charles Bull, Barghausen Consulting Engineers, Inc. (via email only) Robert Warshefski, Greenberg Farrow Architects (via email only) GDI Project: Greenberg-3-04 RE: Addendum 1 Pervious Pavements and Pond Slope Stability Commercial Warehouse Building Renton, Washington INTRODUCTION GeoDesign, Inc. is pleased to submit this addendum providing geotechnical information for the proposed commercial warehouse building located northwest of the intersection of South 180th Street and Lind Avenue SW in Renton, Washington. We provided a geotechnical design report for the site dated December 2, 2014 that includes on-site exploration data as well as geotechnical design recommendations for the project. We were requested by the project design team to provide additional geotechnical information concerning on-site stormwater infiltration, use of pervious pavements, and slope stability of proposed pond slopes. Based on in-progress plans provided to us by Charles Bull of Barghausen Consulting Engineers, Inc. (Barghausen), site development will incorporate a rain garden, a pond, and approximately 53,000 square feet of pervious pavement for partial on-site infiltration. The proposed rain garden will be located on the northeast corner of the parking field, and a detention pond (wetpond) will be located south of there along the east edge of the site. The pervious pavement will occupy the southeast corner of the parking field. We understand that these improvements are considered a part of best management practices (BMPs) for the project in accordance with the King County Storm Water Design Manual (2009) (KCSWDM). As shown on the Civil Section and Details sheet (Sheet C1.5-4 of 41), pond sideslopes are to be constructed at a 3 horizontal to 1 vertical maximum slope. Based on the Civil Site Details plan sheet (Sheet C22 of 41) provided to us, pervious pavement is to consist of porous asphalt concrete (AC) over a stone recharge bed made up of a 2-inch choker course, over a 12-inch section of free-draining base course, over 6 inches of sand, constructed over native subgrade. We did not conduct on-site infiltration testing during our geotechnical evaluation presented in our December 2, 2014 report, which is typically required for the design of the volume of a recharge bed for a pervious pavement Memorandum Page 2 of 9 350 Mission Street SE, Suite 102 l Salem, OR 97302 l 503.968.8787 structure if infiltration is required on site. For this project, we understand that pervious pavement is provided as a BMP and not as a means to infiltrate required volumes. This addendum addresses the stability of the proposed pond slopes, a general characterization of infiltration capacity of on-site soil, and the general structural suitability of the porous AC section provided in the plans. SUBSURFACE CONDITIONS We explored subsurface conditions by completing 12 borings (B-1 through B-12) to depths of 11.5 to 111.5 feet below ground surface (BGS) and eight cone penetration test (CPT) probes (CPT-1 through CPT-8) to approximate depths of 90 feet BGS. The approximate exploration locations as well as descriptions of the subsurface explorations and laboratory testing programs, including boring and CPT logs, are presented in our December 2, 2014 report. In general, the subsurface conditions consist of interbedded layers of silt and sand to the maximum depth explored. Our borings encountered approximately 5 inches of AC and approximately 3 to 3.5 feet of gravel/sand fill at the site surface near the area of the proposed pervious pavements, wetpond, and rain garden (borings B-9 and B-10). Our explorations encountered interbedded layers of silt or sandy silt and silty sand below the upper gravel/sand fill. Laboratory testing indicates that the moisture content of the silt layers generally ranged from 42 to 114 percent and the moisture content of the sand layers ranged from 16 to 43 percent at the time of our explorations. Testing also indicated that the silt has high plasticity and samples of the sand had fines contents of 6 to 15 percent. We did not observe groundwater in our borings completed for the site geotechnical report due to the presence of drilling fluid. The CPT probes conducted at that time indicate that groundwater was approximately 8 to 10 feet BGS. The depth to groundwater is expected to fluctuate and could be as shallow as 5 to 6 feet BGS in response to seasonal changes, changes in surface topography, and other factors not observed in the site vicinity. POND SLOPE STABILITY We used the computer program SLOPE/W to evaluate pond slope stability by using limit equilibrium methods. We conducted our analyses at cross section locations X and Y noted on the Civil Section and Details sheet (Sheet C1.5-4 of 41) under three different scenarios: (1) the stability of the pond slopes with the pond filled with water, (2) the stability of the pond slopes if the pond were filled and then emptied quickly (rapid drawdown), and (3) the stability of the pond slopes where the pond is partially filled, such as when area groundwater is at levels that would enter the pond (shallow groundwater levels per the report). The rapid drawdown condition in a pond can result in saturated slopes as the pond is emptied quickly and water is retained in the slope soil. The output for the stability analyses is provided in the form of a cross section view with the minimum factor of safety shown for the three scenarios described above. The output results are presented in the Attachment of this addendum and include soil parameters used in the analyses. Memorandum Page 3 of 9 350 Mission Street SE, Suite 102 l Salem, OR 97302 l 503.968.8787 Results indicate stable slopes with factors of safety greater than 1.5 under both scenarios described above. Factors of safety decrease for the rapid drawdown condition compared to the full pond condition, but remain above acceptable factors of safety. Surficial sloughing of the sideslopes may also occur during a rapid drawdown condition that may require redress and repair of the pond sideslopes. Based on the potential for shallow groundwater and the sandy soil near the proposed excavation depths for the pond, the pond bottom will likely require ballast-type stabilization material in order to maintain a stable base during construction and during periods of rapid rise in groundwater elevations. Construction without significant dewatering may be possible during extended dry periods and if excavation remains above the level of groundwater. If groundwater is present at or near the depth of excavation, dewatering will be required in order to maintain a stable slope during construction. As water infiltrates the excavation in sandy soil, a “running sand” condition, where a slurry of sand and water infiltrate the excavation as the water runs in, may result. “Running sand” entering into the excavation will result in an unstable slope and base. It is not possible to pump the running slurry out of an excavation with conventional sump pump equipment. It will likely only be possible to dewater sufficiently for construction using a system with well point dewatering points external to the excavation. It is impractical to dewater internally with sumps if a “running sand” condition is occurring or if the excavated slopes or base are becoming unstable from the water infiltration. A 1- to 2-foot-thick layer of quarry spall or large ballast rock should be incorporated to stabilize the pond base and slopes that will be below the depth of area groundwater during prolonged wet periods. As discussed with Mr. Bull at Barghausen, this method has been successfully used on similar projects in the area. Pond water levels will likely remain elevated during prolonged wet periods at an elevation consistent with depth to groundwater in the area. Timing of the excavation should be carefully planned by the site contractor to occur when groundwater can be adequately managed by dewatering or is below the depth of excavation. PERVIOUS PAVEMENT Pervious pavements are typically incorporated into development projects in order to capture stormwater from developed (impervious) areas developed by paving or structures and allowing it to seep into the ground. The pavement structure includes a layer of porous AC or concrete over open- graded choker rock, base rock, and sand. Use of pervious pavements is also considered a BMP by local agencies, including KCSWDM. The aggregate and sand sections beneath the pavement provide storage of stormwater for infiltration for given design event levels and must be designed to support design traffic levels as well. SITE INFILTRATION Infiltration rate is the rate at which water penetrates a soil, expressed as a velocity. It is measured one-dimensionally as the water flows into a two-dimensional soil area and is constrained by a soil’s Memorandum Page 4 of 9 350 Mission Street SE, Suite 102 l Salem, OR 97302 l 503.968.8787 capacity and the rate at which water is applied. A soil’s infiltration capacity is affected by many factors, including gradation, type, consistency, level of saturation, proximity to static water levels, variability within the soil unit, the infiltration system and soil interface, and other physical factors. Infiltration varies greatly under saturated and unsaturated conditions. Stormwater management design considers long-term conditions, so infiltration rates should be considered for saturated soil and not derived from index tests, which is commonly done when considering design of septic system drain fields. In saturated soil, the infiltration rate is essentially equivalent to the soil coefficient of permeability, or hydraulic conductivity. Also, the final infiltration rate used by a stormwater design engineer is calculated by applying correction factors to the infiltration rate provided based on in situ conditions. We did not conduct on-site infiltration tests. As requested by the project team, this discussion is intended to characterize the anticipated infiltration of on-site material encountered in our geotechnical borings based on material types encountered in the area of the proposed infiltration facilities. The plans provided to us indicate pervious pavements and a rain garden and pond on the east side of the site near boring locations B-9 and B-10. The area where pervious pavements are located was initially designed as light-duty AC. Therefore, we anticipate that surface grades and catch basins will remain as originally designed in order to appropriately manage stormwater that cannot be stored or infiltrated. Based on borings B-9 and B-10, there is approximately 3 to 3.5 feet of gravel/sand fill beneath the existing AC, underlain by 3.5 to 5 feet of silt with trace sand, in turn underlain by silty sand or sand with trace silt. The sandier material is generally below a depth of 7 feet BGS. We anticipate an infiltration rate of 6 to 8 inches per hour is possible in the upper gravel with sand fill. This layer has a limited vertical extent (3 to 3.5 feet), and the upper portions of this layer may be removed during site grading in order to accommodate the overall pavement section. We anticipate significantly lower infiltration rates in the underlying silt layer of 0 to 0.25 inch per hour. Although anticipated infiltration rates would be higher (1 to 3 inches per hour) in the cleaner sand underlying the silt layer, they are at or below the level of where groundwater is expected to rise during prolonged periods of wet weather (5 to 6 feet BGS) and would not be capable of infiltrating stormwater. Although the upper gravel with sand fill layer would be directly under the proposed pervious AC section, it is limited in depth. General infiltration in the area will be limited by the lower infiltration capacity of the silt layer. Also, the final rock depth of the proposed pervious section structure may further reduce the depth of the upper gravel fill. The infiltration rates estimated above are based on textural evaluation of the materials encountered, and factors of safety have not been applied for the type of infiltration system being considered or variability of underlying soil across the area. In our opinion, and consistent with the state of the practice, correction factors should be applied to any anticipated or measured rate if required for infiltration design. Appropriate correction factors should be applied by the project civil engineer to determine long-term infiltration parameters to account for potential soil variability across the proposed area (portions are located beneath the existing store), repeated wetting and drying that Memorandum Page 5 of 9 350 Mission Street SE, Suite 102 l Salem, OR 97302 l 503.968.8787 occur in this area, degree of in-system filtration, frequency and type of system maintenance, vegetation, potential for siltation and bio-fouling, etc., as well as system design correction factors for overflow or redundancy and base and basin size. The actual depths, lateral extent, and estimated infiltration rates can vary from the values anticipated above. If required, the design infiltration values should be confirmed by field testing completed during installation. Field testing/confirmation during construction is often required in large or long systems, or other situations where soil conditions may vary within the area where the system is constructed, but not typically conducted for systems that are installed but are not required for on- site stormwater disposal (installed as part of BMPs). In general, the infiltration flow rate of a focused stormwater system typically diminishes over time as suspended solids and precipitates in the stormwater slowly clog the void spaces between the soil particles or cake on the infiltration surface. The serviceable life of a stormwater system can be extended by pre-filtering or with on-going maintenance. Eventually, most systems will fail and will need to be replaced or have media regenerated or replaced. We recommend that infiltration systems include an overflow that is connected to a suitable discharge point. Also, infiltration systems can cause localized high groundwater levels and should not be located near basement walls, retaining walls, or other embedded structures unless these are specifically designed to account for the resulting hydrostatic pressure. Successful design and implementation of stormwater infiltration systems and whether a system is suitable for a development depend on several site-specific factors, including soil type and consistency and the depth to static groundwater. Stormwater infiltration systems are generally best suited for sites having sandy or gravelly soil with saturated hydraulic conductivities greater than 1 to 2 inch per hour. Silty or clayey sites, including silty sand and clayey sand or gravel (gravel where the matrix is clayey) are generally not well-suited for rapid stormwater infiltration. Soil that has fine- grained matrices is susceptible to volumetric change and softening during wetting and drying cycles. Fine-grained soil also has large variations in the magnitude of infiltration rates because of bedding and stratification that occurs during deposition and often has thin layers of less permeable or impermeable soil within a larger layer. Typically, we do not recommend using infiltration systems where groundwater is less than 10 feet below the bottom of the proposed system unless the host soil is very permeable or high rates of infiltration are not required. As discussed in the “Subsurface Conditions” section of this addendum, the regional groundwater table is expected to be 8 to 10 feet BGS and could be as shallow as 5 to 6 feet BGS. Groundwater is expected to rise during periods of persistent wet weather. Considering the potential for shallow groundwater at the site and the potential for highly variable types and extent of fill across the site, we do not recommend stormwater infiltration be used as the exclusive method of stormwater management for this portion of the parking lot. Memorandum Page 6 of 9 350 Mission Street SE, Suite 102 l Salem, OR 97302 l 503.968.8787 PAVEMENT STRUCTURE Our December 2, 2014 geotechnical report for the site provides pavement section recommendations for the site for both standard-duty and heavy-duty sections of conventional AC. The proposed pervious pavement area in the southeast portion of the site as shown in the plans provided to us by Barghausen is incorporated into an area of standard-duty AC (noted as light-duty asphalt on the plan sheet). The standard-duty section provided in the report is 3.5 inches of AC over 8 inches of aggregate base (total 11.5 inch section). The proposed porous asphalt pavement section provided in the plan sheet consists of 3 inches of porous asphalt, over 2 inches of choker rock, over 12 inches of free-draining base course (clean aggregate base), over 6 inches of sand (23 inches total section). In order to minimize the depth of excavation of the upper gravel fill material already in place at the site and to create a consistent depth to subgrade (depth at bottom of base rock section), we conducted an analysis of the required pavement section to support anticipated standard-duty traffic levels as described in our geotechnical report for the site for both conventional AC and porous asphalt pavement. Traffic and material parameter assumptions used for this evaluation are consistent with those presented in our site geotechnical report. The revised porous asphalt pavement section below considers only the structural capacity of the pavement section and not the required reservoir volume (storage capacity for water from storm events) of the section. If design of the porous asphalt section as presented requires the thicknesses of material included in the plan as a capacity reservoir for infiltration, the revised sections recommended below should not be implemented. If storage capacity is not required as part of the overall section, we recommend a pavement section thickness for the porous asphalt of 3 inches of porous asphalt, over 2 inches of choker rock, over 10 inches of free-draining base course (clean aggregate base), over prepared subgrade (15 inches total section). The revised section deletes the 6 inches of sand beneath the rock and 2 inches of base course rock and reduces the depth of excavation by 8 inches across the area. We recommend that a geotextile fabric be placed as a barrier between the prepared subgrade and the imported base rock section to minimize migration of fines and provide additional support to the overlying pavement structure. The geotextile should have a minimum Mullen burst strength of 250 pounds per square inch for puncture resistance and an apparent opening size between U.S. Standard No. 70 and No. 100 Sieves as recommended in the site geotechnical report. In order to match the total section with that of the porous asphalt section, a revised AC section of 3 inches of AC over 12 inches of aggregate base (15 inches total section) can be used in this area for standard-duty traffic. The 12 inches of aggregate base can consist of 2 inches of choker rock, over 10 inches of free-draining base course, over geotextile fabric as recommended above for the porous asphalt section in order to provide consistent base preparation over the entire area. The structural capacity of the revised AC section exceeds the calculated value of the initial recommendation. The revised section recommendations above assume that all site preparation, material recommendations, and construction considerations included in the site geotechnical report are included as a part of project plans and specifications. Recommendations for site preparation and Memorandum Page 7 of 9 350 Mission Street SE, Suite 102 l Salem, OR 97302 l 503.968.8787 material requirements for the standard AC section are provided in our geotechnical report. Supplemental recommendations for the porous asphalt section are provided below. Pervious Pavement Construction Considerations The long-term performance of pervious pavements is reliant upon proper design, installation, and long-term maintenance. As a result, we recommend that the contractor supplying and installing the pervious pavement has at least three years successful experience installing pervious pavements. In addition, at least one test panel should be constructed and reviewed prior to installation of the entire area of pervious pavements. The subgrade beneath pervious pavements is typically graded to be relatively flat (less than 3 percent slope) to prevent uneven ponding of water within the storage aggregate. For this project, the pervious pavement section is only a portion of the overall parking field and has a subgrade elevation (below the aggregate rock section) that is lower in elevation than the adjacent standard AC section. The subgrade beneath the pervious pavement section should be sloped sufficiently to drain away from standard AC sections or otherwise routed to suitable drainage, so as not to allow infiltrating water to migrate into the standard AC section base rock. The subgrade should be cut from the edges, not trafficked by heavy machinery, and remain in an uncompacted state. Irrespective, the subgrade should be proof rolled with a fully loaded dump truck or water truck to identify soft or pumping areas. Soft areas, or areas that are excessively compacted by construction equipment, should be removed and replaced by additional storage aggregate. Landscaping areas that are adjacent to pervious pavements should be designed to prevent run-off from washing over the pavements, otherwise sediment can clog the pervious materials. During and after construction, stockpiles of landscaping materials (i.e., topsoil, bark dust, etc.) and construction materials (i.e., sand, gravel, etc.) should not be placed on the pervious pavements. Extreme care should be taken to prevent trafficking of muddy construction equipment over pervious pavements. Maintenance should consist of periodic cleaning by vacuuming and flushing with high volume water at low pressures. We note that sweeping is not an effective method for cleaning of pervious pavements; in fact, available information indicates that sweeping may decrease the permeability of pervious pavements by clogging pores. Pavement Materials The porous asphalt concrete (PAC) should be ½-inch PAC and rolled until the entire surface has been compacted with at least four coverages by the breakdown and intermediate rollers and finished with additional coverages by the finish roller. Although typical provisions indicate the minimum lift thickness be twice the maximum aggregate size, we recommend specifying a minimum lift thickness of 2 inches for ½-inch PAC. Therefore, PAC for the 3-inch section as recommended above should be Memorandum Page 8 of 9 350 Mission Street SE, Suite 102 l Salem, OR 97302 l 503.968.8787 placed in a single lift. A polymer-modified asphalt binder is required in the wearing course. Asphalt binder should be performance graded and conform to PG 70-22ER or better. Choker Aggregate Imported granular material used as choker aggregate beneath pervious pavements should be a 3/8- to 3/4-inch, uniformly graded crushed rock or crushed gravel with at least two mechanically fractured faces and that meets the gradation in Table 1. Table 1. Choker Aggregate Gradation Sieve Size Percent Passing 1½ -inch 100 1-inch 95 – 100 ½-inch 25 – 60 #4 0 – 10 #8 0 – 5 Storage Aggregate Imported granular material used as storage aggregate (free-draining base course) beneath pervious pavements should be clean crushed rock or crushed gravel with at least two mechanically fractured faces that meets the gradation of Washington Standard Specifications for Road, Bridge, and Municipal Construction (2014) 9-03 - Aggregates. The imported granular material should be placed in maximum 6-inch-thick lifts (compacted thickness) and compacted until proof rolling indicates that a firm, unyielding surface is present. LIMITATIONS We have prepared this addendum for use by Greenberg Farrow Architects, Barghausen Consulting Engineers, Inc., and members of the project design and construction teams for the proposed project. The data and recommendations herein are presented as an addendum to our December 2, 2014 geotechnical design report for the site. Together with that information, the data and conclusions can be used for bidding or estimating purposes, but our conclusions and interpretations should not be construed as warranty of the subsurface conditions and are not applicable to other nearby sites. The development plans were preliminary at the time this addendum was prepared. When the design has been finalized, we request that we be retained to review our conclusions and recommendations and to provide a written modification or verification. Within the limitations of scope, schedule, and budget, our services have been executed in accordance with generally accepted practices in this area at the time the addendum was prepared. No warranty, express or implied, should be understood. Memorandum Page 9 of 9 350 Mission Street SE, Suite 102 l Salem, OR 97302 l 503.968.8787 We appreciate the opportunity to be of service to you. Please call if you have questions concerning this addendum or if we can provide additional services. JCV:SPM:kt Attachment One copy submitted (via email only) Document ID: Greenberg-3-04-020315-geoa-1.docx © 2015 GeoDesign, Inc. All rights reserved. Signed 02/03/2015 ATTACHMENT Tab 7.0 16836.006.doc 7.0 OTHER PERMITS Permits Obtained: Construction Stormwater General Permit (Department of Ecology) - Refer to Appendix D of the Stormwater Pollution Prevention Plan (SWPPP) Permits in Process - documents not available at this time: Building Permit for the Building Building Permit for the Detention Vault Utility Permit Side Sewer Permit Food Permit (Health Department Approval) Backflow Permit Sign Permits Fire Sprinkler Permit Elevator Permit Tab 8.0 16836.006.doc 8.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN ANALYSIS AND DESIGN A. Erosion and Sediment Control (ESC) Plan Analysis and Design Erosion and Sedimentation Control Plans are provided with this submittal. In addition, the included Stormwater Pollution Prevention Plan prescribes additional measures for discharge requirements including turbidity monitoring and pH sampling. These requirements will dictate the basis of the design for specific selection and sizing of advanced BMP treatment elements such as sand media filters. . Stormwater Pollution Prevention Plan For IKEA Seattle Store Redevelopment Prepared For Northwest Regional Office 3190 - 160th Avenue SE Bellevue, WA 98008-5452 425-649-7000 Owner Developer Operator/Contractor IKEA Property Inc IKEA Property Inc Deacon Corp. of Washington 420 Alan Wood Road 420 Alan Wood Road 2375 - 130th Avenue N.E., Suite 200 Conshohocken, PA 19428 Conshohocken, PA 19428 Bellevue, WA 98005 Project Site Location 601 SW 41st St and 800 SW 43rd St. Renton, WA 98057 Certified Erosion and Sediment Control Lead Jim Meyer - Deacon Corp. of Washington SWPPP Prepared By Barghausen Consulting 18215 72nd Ave So Kent WA 98032 425 251 6222 Charles Bull, Project Engineer SWPPP Preparation Date 02/20/2015 Revised 9/16/15 Approximate Project Construction Dates 07/2015 07/2017 i 16836 IKEA SWPPP .doc Contents 1.0 Introduction ...............................................................................................................................1 2.0 Site Description ........................................................................................................................3 2.1 Existing Conditions ...........................................................................................................3 2.2 Proposed Construction Activities ......................................................................................4 3.0 Construction Stormwater BMPs ...............................................................................................6 3.1 The 12 BMP Elements .......................................................................................................6 3.1.1 Element #1 – Mark Clearing Limits ...................................................................6 3.1.2 Element #2 – Establish Construction Access .....................................................6 3.1.3 Element #3 – Control Flow Rates .......................................................................7 3.1.4 Element #4 – Install Sediment Controls .............................................................7 3.1.5 Element #5 – Stabilize Soils ...............................................................................8 3.1.6 Element #6 – Protect Slopes ...............................................................................9 3.1.7 Element #7 – Protect Drain Inlets .......................................................................9 3.1.8 Element #8 – Stabilize Channels and Outlets ...................................................10 3.1.9 Element #9 – Control Pollutants .......................................................................10 3.1.10 Element #10 – Control Dewatering .................................................................11 3.1.11 Element #11 – Maintain BMPs .......................................................................12 3.1.12 Element #12 – Manage the Project ..................................................................12 3.1.11 Element #11 – Maintain BMPs .......................................................................15 3.1.12 Element #12 – Manage the Project ..................................................................15 3.1.13 Element #13 – Protect Low Impact Development BMPs ...............................18 3.2 Site Specific BMPs ..........................................................................................................18 3.3 Additional Advanced BMPs ............................................................................................18 4.0 Construction Phasing and BMP Implementation ...................................................................21 5.0 Pollution Prevention Team ......................................................................................................22 5.1 Roles and Responsibilities ...............................................................................................22 5.2 Team Members ................................................................................................................22 6.0 Site Inspections and Monitoring .............................................................................................24 6.1 Site Inspection .................................................................................................................24 6.1.1 Site Inspection Frequency ................................................................................24 6.1.2 Site Inspection Documentation .........................................................................25 6.2 Stormwater Quality Monitoring ......................................................................................25 6.2.1 Turbidity Sampling ...........................................................................................25 6.2.2 pH Sampling .....................................................................................................26 7.0 Reporting and Recordkeeping ................................................................................................27 7.1 Recordkeeping .................................................................................................................27 7.1.1 Site Log Book ...................................................................................................27 ii 16836 IKEA SWPPP .doc 7.1.2 Records Retention.............................................................................................27 7.1.3 Access to Plans and Records ............................................................................27 7.1.4 Updating the SWPPP ........................................................................................27 7.2 Reporting .........................................................................................................................28 7.2.1 Discharge Monitoring Reports .........................................................................28 7.2.2 Notification of Noncompliance ........................................................................28 7.2.3 Permit Application and Changes ......................................................................28 Appendix A – Site Plans .........................................................................................................29 Appendix B – Construction BMPs .........................................................................................36 Appendix C – Alternative BMPs ............................................................................................36 Appendix D – General Permit ................................................................................................38 Appendix E – Site Inspection Forms (and Site Log) ..............................................................39 Appendix F – Engineering Calculations .................................................................................47 Appendix A Site plans Vicinity map (with all discharge points) Site plan with TESC measures Appendix B Construction BMPs Possibly reference in BMPs, but likely it will be a consolidated list so that the applicant can photocopy from the list from the SWMM. Appendix C Alternative Construction BMP list List of BMPs not selected, but can be referenced if needed in each of the 12 elements Appendix D General Permit Appendix E Site Log and Inspection Forms Appendix F Engineering Calculations (if necessary) Flows, ponds, etc… Stormwater Pollution Prevention Plan 1 16836 IKEA SWPPP .doc 1.0 Introduction This Stormwater Pollution Prevention Plan (SWPPP) has been prepared as part of the NPDES stormwater permit requirements for the IKEA Seattle Store Redevelopment improvement project in Renton, Washington. The project contains the existing IKEA store and lies west of Lind Avenue SW and south of SW 41st St. and north of SW 43rd St. Construction activities will include demolition, excavation, grading, relocation of onsite services/utilities and the building of a two-story steel framed building. The purpose of this SWPPP is to describe the proposed construction activities and all temporary and permanent erosion and sediment control (TESC) measures, pollution prevention measures, inspection/monitoring activities, and recordkeeping that will be implemented during the proposed construction project. The objectives of the SWPPP are to: 1. Implement Best Management Practices (BMPs) to prevent erosion and sedimentation, and to identify, reduce, eliminate or prevent stormwater contamination and water pollution from construction activity. 2. Prevent violations of surface water quality, ground water quality, or sediment management standards. 3. Prevent, during the construction phase, adverse water quality impacts including impacts on beneficial uses of the receiving water by controlling peak flow rates and volumes of stormwater runoff at the Permittee’s outfalls and downstream of the outfalls. This SWPPP was prepared using the Ecology SWPPP Template downloaded from the Ecology website and dated July 2, 2005. This SWPPP was prepared based on the requirements set forth in the Construction Stormwater General Permit, Stormwater Management Manual for Western Washington (SWMMWW 2005). The 2012 revision of Vol. II of the Stormwater Management Manual for Western Washington (SWMMWW) has been used as a guildline to address the BMP's for this project and to update practices. Volume II focuses on managing stormwater impacts associated with construction activities. Best management practices (BMPs) that are properly planned, installed, and maintained can minimize stormwater impacts, such as heavy stormwater flows, soil erosion, water-borne sediment from exposed soils, and degradation of water quality, from onsite pollutant sources. The report is divided into seven main sections with several appendices that include stormwater related reference materials. The topics presented in the each of the main sections are: Section 1 – INTRODUCTION. This section provides a summary description of the project, and the organization of the SWPPP document. Stormwater Pollution Prevention Plan 2 16836 IKEA SWPPP .doc Section 2 – SITE DESCRIPTION. This section provides a detailed description of the existing site conditions, proposed construction activities, and calculated stormwater flow rates for existing conditions and post-construction conditions. Section 3 – CONSTRUCTION BMPs. This section provides a detailed description of the BMPs to be implemented based on the 12 required elements of the SWPPP (SWMMEW 2004). Section 4 – CONSTRUCTION PHASING AND BMP IMPLEMENTATION. This section provides a description of the timing of the BMP implementation in relation to the project schedule. Section 5 – POLLUTION PREVENTION TEAM. This section identifies the appropriate contact names (emergency and non-emergency), monitoring personnel, and the onsite temporary erosion and sedimentation control inspector Section 6 – INSPECTION AND MONITORING. This section provides a description of the inspection and monitoring requirements such as the parameters of concern to be monitored, sample locations, sample frequencies, and sampling methods for all stormwater discharge locations from the site. Section 7 – RECORDKEEPING. This section describes the requirements for documentation of the BMP implementation, site inspections, monitoring results, and changes to the implementation of certain BMPs due to site factors experienced during construction. Supporting documentation and standard forms are provided in the following Appendices: Appendix A – Site Plans – See also IKEA Redevelopment Civil plan set Appendix B – Construction BMPs Appendix C – Alternative BMPs Appendix D – General Permit Appendix E – Site Inspection Forms (and Site Log) Appendix F – Engineering Calculations Stormwater Pollution Prevention Plan 3 16836 IKEA SWPPP .doc 2.0 Site Description 2.1 Existing Conditions The proposed project consists of demolishing an existing IKEA store and warehouse structure used for some storage and parking and constructing a new store and assocated parking lot. The property is approximately 29 acres in size, containing two tax parcels (362304-9113 and 312305-9169). The site is located at the northwest corner of intersection of S.W. 43rd Street and Lind Avenue S.W., in a portion of Sections 31 and 36, Township 23 North, Range 4 East, Willamette Meridian, in the City of Renton. The site is rectangular in shape and fronts S.W. 41st Street on the north, Lind Avenue S.W. on the east , and S.W. 43rd Street on the south. The site is bound along the east property line and shares access and some utilities with an existing warehouse development used by Alliance Packaging. The existing on-site improvements consist of storm, sewer, and water utilities, dry utilities including gas, power and telephone, landscaping, and paved parking areas. The site has access to the fronting streets along with the shared access along the east property line mentioned above. Streets will require frontage improvements, including continuous new sidewalk and planter strip along SW Lind Avenue and SW 43rd Street. SW 41st Street requires new driveway approaches and the associated sidewalk, landscaping improvements. On-site soils are mapped as Woodinville silt loam and Snohomish silt loam. The Reoprt of Geotechnical Engineering Services dated December 2, 2014 by GeoDesign indicated asphalt over 2 to 5 feet of gravel/sand fill. A sandy/silt and silty/sand was encountered below the fill. Ground water was found at 8 to 10 feet below grade and is expected to fluctuate to as shallow as 5 to 6 feet below grade. The topography on site is generally flat, with minor relief, in order to drain areas to catch basins surrounding two existing large buildings serving as the IKEA store at this time. There are three separate drainage basins located on site, each with their own discharge location. Two of the basins are on the west side of the site; the other is the remainder of the site. The two basins along the west side of the site discharge at separate locations, but converge within ¼ mile downstream of the site, before discharging into Spring Brook Creek. The east basin discharges from the northeast corner of the site, and enters Spring Brook Creek approximately 1 mile downstream of the site. Therefore there are two separate threshold discharge areas on-site. The existing site contains 26.97 acres of impervious area, in which 17.48 acres is roof area, with the remaining area consisting of asphalt pavement, sidewalks and curb and gutter. Stormwater Pollution Prevention Plan 4 16836 IKEA SWPPP 2015-9-16 .doc 2.2 Proposed Construction Activities The IKEA Seattle Store improvement project and will result the construction of a two- story commercial building that will be used as a storage and retail area for home furnishings and accessories. The proposed building will be located westerly on the site with a new asphalt paved parking lot on the front (east ), south, north, and a paved loading dock area on the west. A conveyance system consisting of catch basins and storm pipes will be constructed in the parking areas to collect drainage from impervious surfaces and convey runoff to the proposed water quality facilities. Since there are three separate drainage basins located on site, three separate water quality facilities will be used to treat the stormwater runoff, a wetpond, wetvault, and a Filterra unit. A stormwater treatment vault will be constructed in the northwest corner of the site. The wetvault will provide Basic Water Quality for the northwestern portion of the site, approximately 3.65 acres. A stormwater treatment wetpond will be constructed in the southeast corner of the site. The proposed wetpond will provide Basic Water Quality for the eastern half of the site, approximately 18.1 acres. A precast stormwater treatment vault , Filterra unit will be constructed in the southwest corner of the site. The Filterra unit will provide Basic Water Quality for the southwestern portion of the site, approximately 1.01 acres. New sanitary, electrical, gas, and storm drain utilities will also be constructed. Per the City of Renton Flow Control Application Map, the project is subject to the Peak Rate Flow Control Standard, in which the project must match developed peak discharge rates to the existing site conditions for the 2-, 10-, and 100-year return periods. Since there will be less impervious area in the proposed condition than there was in the existing condition, flow control will not be needed, as the peak flows from the existing site are larger than the peak flow of the proposed site Construction activities will include site preparation, TESC installation, demolition of the existing warehouse (garage) structure, excavation for the building foundations and pre- cast concrete stormwater vault, poured concrete foundations, concrete tilt-up building construction, site-wide grading, and asphalt paving. The schedule and phasing of BMPs during construction is provided in Section 4.0. The following summarizes details regarding site areas: Total site area: 29 acres Percent impervious area before construction: 93 % Percent impervious area after construction: 86 % Disturbed area during construction: 29 acres Stormwater Pollution Prevention Plan 5 16836 IKEA SWPPP .doc Disturbed area that is characterized as impervious (i.e., access roads, staging, parking): 27 acres All stormwater flow calculations are provided in Appendix F. Stormwater Pollution Prevention Plan 6 16836 IKEA SWPPP .doc 3.0 Construction Stormwater BMPs 3.1 The 12 BMP Elements 3.1.1 Element #1 – Mark Clearing Limits To protect adjacent properties and to reduce the area of soil exposed to construction, the limits of construction will be clearly marked before land-disturbing activities begin. Trees that are to be preserved, as well as all sensitive areas and their buffers, shall be clearly delineated, both in the field and on the plans. In general, natural vegetation and native topsoil shall be retained in an undisturbed state to the maximum extent possible. The BMPs relevant to marking the clearing limits that will be applied for this project include: Stake and Wire Fence (BMP C104) High Visibility Plastic or Metal Fence (BMP C103) Alternate BMPs for marking clearing limits are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.2 Element #2 – Establish Construction Access Construction access or activities occurring on unpaved areas shall be minimized, yet where necessary, access points shall be stabilized to minimize the tracking of sediment onto public roads, and wheel washing, street sweeping, and street cleaning shall be employed to prevent sediment from entering state waters. All wash wastewater shall be controlled on site. The specific BMPs related to establishing construction access that will be used on this project include: Stabilized Construction Entrance (BMP C105) Wheel Wash (BMP C106) The roads shall be swept daily should sediment collect on them. Wheel washing shall occur at locations where the sediment will be retained on site. Alternate construction access BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues Stormwater Pollution Prevention Plan 7 16836 IKEA SWPPP .doc that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.3 Element #3 – Control Flow Rates In order to protect the properties and waterways downstream of the project site, stormwater discharges from the site will be controlled. The specific BMPs for flow control that shall be used on this project include: Sediment Trap (BMP C240) Temporary Sediment Pond (BMP C241) Alternate flow control BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, the project must comply with Minimum Requirement 7 (Ecology 2005). In general, discharge rates of stormwater from the site will be controlled where increases in impervious area or soil compaction during construction could lead to downstream erosion, or where necessary to meet local agency stormwater discharge requirements (e.g. discharge to combined sewer systems). 3.1.4 Element #4 – Install Sediment Controls All stormwater runoff from disturbed areas shall pass through an appropriate sediment removal BMP before leaving the construction site or prior to being discharged to an infiltration facility. The specific BMPs to be used for controlling sediment on this project include: Gravel Filter Berm (BMP C232) Silt Fence (BMP C233) Storm Drain Inlet Protection (BMP C220) Construction Stormwater Filtration (BMP C251) Alternate sediment control BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or Stormwater Pollution Prevention Plan 8 16836 IKEA SWPPP .doc inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. In addition, sediment will be removed from paved areas in and adjacent to construction work areas manually or using mechanical sweepers, as needed, to minimize tracking of sediments on vehicle tires away from the site and to minimize washoff of sediments from adjacent streets in runoff. Whenever possible, sediment laden water shall be discharged into onsite, relatively level, vegetated areas (BMP C240 paragraph 5, page 4-102). In some cases, sediment discharge in concentrated runoff can be controlled using permanent stormwater BMPs (e.g., infiltration swales, ponds, trenches). Sediment loads can limit the effectiveness of some permanent stormwater BMPs, such as those used for infiltration or biofiltration; however, those BMPs designed to remove solids by settling (wet ponds or detention ponds) can be used during the construction phase. When permanent stormwater BMPs will be used to control sediment discharge during construction, the structure will be protected from excessive sedimentation with adequate erosion and sediment control BMPs. Any accumulated sediment shall be removed after construction is complete and the permanent stormwater BMP will be restabilized with vegetation per applicable design requirements once the remainder of the site has been stabilized. The following BMPs will be implemented as end-of-pipe sediment controls as required to meet permitted turbidity limits in the site discharge(s). Prior to the implementation of these technologies, sediment sources and erosion control and soil stabilization BMP efforts will be maximized to reduce the need for end-of-pipe sedimentation controls. Construction Stormwater Filtration (BMP C251) 3.1.5 Element #5 – Stabilize Soils Exposed and unworked soils shall be stabilized with the application of effective BMPs to prevent erosion throughout the life of the project. The specific BMPs for soil stabilization that shall be used on this project include: Plastic Covering (BMP C123) Gradient Terraces (BMP C131) Alternate soil stabilization BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided Stormwater Pollution Prevention Plan 9 16836 IKEA SWPPP .doc in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, no soils shall remain exposed and unworked for more than 7 days during the dry season (May 1 to September 30) and 2 days during the wet season (October 1 to April 30). Regardless of the time of year, all soils shall be stabilized at the end of the shift before a holiday or weekend if needed based on weather forecasts. In general, cut and fill slopes will be stabilized as soon as possible and soil stockpiles will be temporarily covered with plastic sheeting. All stockpiled soils shall be stabilized from erosion, protected with sediment trapping measures, and where possible, be located away from storm drain inlets, waterways, and drainage channels. 3.1.6 Element #6 – Protect Slopes All cut and fill slopes will be designed, constructed, and protected in a manner than minimizes erosion. The following specific BMPs will be used to protect slopes for this project: Temporary and Permanent Seeding (BMP C 120) Alternate slope protection BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.7 Element #7 – Protect Drain Inlets All storm drain inlets and culverts made operable during construction shall be protected to prevent unfiltered or untreated water from entering the drainage conveyance system. However, the first priority is to keep all access roads clean of sediment and keep street wash water separate from entering storm drains until treatment can be provided. Storm Drain Inlet Protection (BMP C220) will be implemented for all drainage inlets and culverts that could potentially be impacted by sediment-laden runoff on and near the project site. The following inlet protection measures will be applied on this project: • Excavated Drop Inlet Protection • Block and Gravel Drop Inlet Protection • Gravel and Wire Drop Inlet Protection • Catch Basin Filters Stormwater Pollution Prevention Plan 10 16836 IKEA SWPPP .doc Curb Inlet Protection • Block and Gravel Curb Inlet Protection Culvert Inlet Protection • Culvert Inlet Sediment Trap If the BMP options listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D), or if no BMPs are listed above but deemed necessary during construction, the Certified Erosion and Sediment Control Lead shall implement one or more of the alternative BMP inlet protection options listed in Appendix C. 3.1.8 Element #8 – Stabilize Channels and Outlets Where site runoff is to be conveyed in channels, or discharged to a stream or some other natural drainage point, efforts will be taken to prevent downstream erosion. The specific BMPs for channel and outlet stabilization that shall be used on this project include: Check Dams (BMP C207) Site runoff shall be discharged to a sediment pond and/or trap Alternate channel and outlet stabilization BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, all temporary on-site conveyance channels shall be designed, constructed, and stabilized to prevent erosion from the expected peak 10 minute velocity of flow from a Type 1A, 10-year, 24- hour recurrence interval storm for the developed condition. Alternatively, the 10-year, 1- hour peak flow rate indicated by an approved continuous runoff simulation model, increased by a factor of 1.6, shall be used. Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent streambanks, slopes, and downstream reaches shall be provided at the outlets of all conveyance systems. 3.1.9 Element #9 – Control Pollutants All pollutants, including waste materials and demolition debris, that occur onsite shall be handled and disposed of in a manner that does not cause contamination of stormwater. Good housekeeping and preventative measures will be taken to ensure that the site will be kept clean, well organized, and free of debris. If required, BMPs to be implemented to control specific sources of pollutants are discussed below. Stormwater Pollution Prevention Plan 11 16836 IKEA SWPPP .doc Vehicles, construction equipment, and/or petroleum product storage/dispensing: All vehicles, equipment, and petroleum product storage/dispensing areas will be inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent leaks or spills. On-site fueling tanks and petroleum product storage containers shall include secondary containment. Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. In order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle. Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. The facility does not require a Spill Prevention, Control, and Countermeasure (SPCC) Plan under the Federal regulations of the Clean Water Act (CWA). 3.1.10 Element #10 – Control Dewatering Currently, no formal dewatering is planned as part of this construction project. Any dewatering water from open cut excavation, tunneling, foundation work, trench, or underground vaults shall be discharged into a controlled conveyance system. Contaminated dewater discharge shall be to ground infiltration or discharge to the sanitary sewer or otherwise contained. The contractor shall be responsible to obtain all permits from King County Waste Water Division if discharging to the sanitary sewer. No discharge of contaminated dewatering water into the downstream drainage course is to occur. Coordinate with the IKEA Construction Manager. Provisions to prevent the comingling of surface water runoff with dewatering water shall be made including but not limited to diversion channels, ditches, piping, and covering. Discharge clean, non-turbid de-watering water, such as well-point ground water, to systems tributary to, or directly into surface waters of the State, as specified in Element #8, provided the de-watering flow does not cause erosion or flooding of receiving waters or interfere with the operation of the system. Channels will be stabilized, per Element #8. Do not route clean dewatering water through stormwater sediment ponds Highly turbid dewatering water from soils known or suspected to be contaminated, or from use of construction equipment, will require additional monitoring and treatment as required for the specific pollutants based on the receiving waters into which the discharge is occurring. Such monitoring is the responsibility of the contractor. However, the dewatering of soils known to be free of contamination will trigger BMPs to trap sediment and reduce turbidity. At a minimum, geotextile fabric socks/bags/cells will Stormwater Pollution Prevention Plan 12 16836 IKEA SWPPP .doc be used to filter this material. Other applicable BMPs to be used for sediment trapping and turbidity reduction include the following: 1. Infiltration. 2. Transport off-site in a vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not pollute state waters. 3. Ecology-approved on-site chemical treatment or other suitable treatment technologies. Alternate dewatering control BMPs are included in Appendix C as a quick reference tool for the onsite inspector in the event the BMP(s) listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit (as provided in Appendix D), the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs listed in Appendix C after the first sign that existing BMPs are ineffective or failing. 3.1.11 Element #11 – Maintain BMPs All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMPs specifications (attached). Visual monitoring of the BMPs will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the site becomes inactive, and is temporarily stabilized, the inspection frequency will be reduced to once every month. All temporary erosion and sediment control BMPs shall be removed within 30 days after the final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil resulting from removal of BMPs or vegetation shall be permanently stabilized. 3.1.12 Element #12 – Manage the Project Erosion and sediment control BMPs for this project have been designed based on the following principles: Design the project to fit the existing topography, soils, and drainage patterns. Emphasize erosion control rather than sediment control. Minimize the extent and duration of the area exposed. Keep runoff velocities low. Stormwater Pollution Prevention Plan 13 16836 IKEA SWPPP .doc Retain sediment on site. Thoroughly monitor site and maintain all ESC measures. Schedule major earthwork during the dry season. In addition, project management will incorporate the key components listed below: As this project site is located west of the Cascade Mountain Crest, the project will be managed according to the following key project components: Phasing of Construction The construction project is being phased to the extent practicable in order to prevent soil erosion, and, to the maximum extent possible, the transport of sediment from the site during construction. Revegetation of exposed areas and maintenance of that vegetation shall be an integral part of the clearing activities during each phase of construction, per the Scheduling BMP (C 162). Seasonal Work Limitations From October 1 through April 30, clearing, grading, and other soil disturbing activities shall only be permitted if shown to the satisfaction of the local permitting authority that silt-laden runoff will be prevented from leaving the site through a combination of the following: Site conditions including existing vegetative coverage, slope, soil type, and proximity to receiving waters; and Limitations on activities and the extent of disturbed areas; and Proposed erosion and sediment control measures. Based on the information provided and/or local weather conditions, the local permitting authority may expand or restrict the seasonal limitation on site disturbance. The following activities are exempt from the seasonal clearing and grading limitations: Routine maintenance and necessary repair of erosion and sediment control BMPs; Stormwater Pollution Prevention Plan 14 16836 IKEA SWPPP .doc Routine maintenance of public facilities or existing utility structures that do not expose the soil or result in the removal of the vegetative cover to soil; and Activities where there is 100 percent infiltration of surface water runoff within the site in approved and installed erosion and sediment control facilities. Coordination with Utilities and Other Jurisdictions Care has been taken to coordinate with utilities, other construction projects, and the local jurisdiction in preparing this SWPPP and scheduling the construction work. Inspection and Monitoring Projects that disturb one or more acres must have, site inspections conducted by a Certified Erosion and Sediment Control Lead (CESCL). Project sites less than one acre (not part of a larger common plan of development or sale) may have a person without CESCL certification conduct inspections. By the initiation of construction , the SWPPP must identify the CESCL or inspector, who shall be present on-site or on-call at all times All BMPs shall be inspected, maintained, and repaired as needed to assure continued performance of their intended function. Site inspections shall be conducted by a person who is knowledgeable in the principles and practices of erosion and sediment control. This person has the necessary skills to: Assess the site conditions and construction activities that could impact the quality of stormwater, and Assess the effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. A Certified Erosion and Sediment Control Lead shall be on-site or on-call at all times. Whenever inspection and/or monitoring reveals that the BMPs identified in this SWPPP are inadequate, due to the actual discharge of or potential to discharge a significant amount of any pollutant, appropriate BMPs or design changes shall be implemented as soon as possible. Stormwater Pollution Prevention Plan 15 16836 IKEA SWPPP .doc Maintaining an Updated Construction SWPPP This SWPPP shall be retained on-site or within reasonable access to the site. The SWPPP shall be modified whenever there is a change in the design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the state. The SWPPP shall be modified if, during inspections or investigations conducted by the owner/operator, or the applicable local or state regulatory authority, it is determined that the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. The SWPPP shall be modified as necessary to include additional or modified BMPs designed to correct problems identified. Revisions to the SWPPP shall be completed within seven (7) days following the inspection. 3.1.11 Element #11 – Maintain BMPs All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP’s specifications. Visual monitoring of the BMPs will be conducted at least once every calendar week and within 24 hours of any rainfall event that causes a discharge from the site. If the site becomes inactive, and is temporarily stabilized, the inspection frequency will be reduced to once every month. All temporary erosion and sediment control BMPs shall be removed within 30 days after the final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil resulting from removal of BMPs or vegetation shall be permanently stabilized. 3.1.12 Element #12 – Manage the Project Erosion and sediment control BMPs for this project have been designed based on the following principles: Design the project to fit the existing topography, soils, and drainage patterns. Emphasize erosion control rather than sediment control. Minimize the extent and duration of the area exposed. Keep runoff velocities low. Retain sediment on site. Stormwater Pollution Prevention Plan 16 16836 IKEA SWPPP .doc Thoroughly monitor site and maintain all ESC measures. Schedule major earthwork during the dry season. In addition, project management will incorporate the key components listed below: As this project site is located west of the Cascade Mountain Crest, the project will be managed according to the following key project components: Phasing of Construction The construction project is being phased to the extent practicable in order to prevent soil erosion, and, to the maximum extent possible, the transport of sediment from the site during construction. Revegetation of exposed areas and maintenance of that vegetation shall be an integral part of the clearing activities during each phase of construction, per the Scheduling BMP (C 162). Seasonal Work Limitations From October 1 through April 30, clearing, grading, and other soil disturbing activities shall only be permitted if shown to the satisfaction of the local permitting authority that silt-laden runoff will be prevented from leaving the site through a combination of the following: Site conditions including existing vegetative coverage, slope, soil type, and proximity to receiving waters; and Limitations on activities and the extent of disturbed areas; and Proposed erosion and sediment control measures. Based on the information provided and/or local weather conditions, the local permitting authority may expand or restrict the seasonal limitation on site disturbance. The following activities are exempt from the seasonal clearing and grading limitations: Routine maintenance and necessary repair of erosion and sediment control BMPs; Stormwater Pollution Prevention Plan 17 16836 IKEA SWPPP .doc Routine maintenance of public facilities or existing utility structures that do not expose the soil or result in the removal of the vegetative cover to soil; and Activities where there is 100 percent infiltration of surface water runoff within the site in approved and installed erosion and sediment control facilities. Coordination with Utilities and Other Jurisdictions Care has been taken to coordinate with utilities, other construction projects, and the local jurisdiction in preparing this SWPPP and scheduling the construction work. Inspection and Monitoring All BMPs shall be inspected, maintained, and repaired as needed to assure continued performance of their intended function. Site inspections shall be conducted by a person who is knowledgeable in the principles and practices of erosion and sediment control. This person has the necessary skills to: Assess the site conditions and construction activities that could impact the quality of stormwater, and Assess the effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. A Certified Erosion and Sediment Control Lead shall be on-site or on-call at all times. Whenever inspection and/or monitoring reveals that the BMPs identified in this SWPPP are inadequate, due to the actual discharge of or potential to discharge a significant amount of any pollutant, appropriate BMPs or design changes shall be implemented as soon as possible. Maintaining an Updated Construction SWPPP This SWPPP shall be retained on-site or within reasonable access to the site. The SWPPP shall be modified whenever there is a change in the design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the state. Stormwater Pollution Prevention Plan 18 16836 IKEA SWPPP .doc The SWPPP shall be modified if, during inspections or investigations conducted by the owner/operator, or the applicable local or state regulatory authority, it is determined that the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. The SWPPP shall be modified as necessary to include additional or modified BMPs designed to correct problems identified. Revisions to the SWPPP shall be completed within seven (7) days following the inspection. 3.1.13 Element #13 – Protect Low Impact Development BMPs Protect all Rain Garden BMPs from sedimentation through installation and maintenance of erosion and sediment control BMPs on portions of the site that drain into the Rain Garden BMPs. Restore the BMPs to their fully functioning condition if they accumulate sediment during construction. Restoring the BMP must include removal of sediment and any sediment- laden Bioretention/rain garden soils, and replacing the removed soils with soils meeting the design specification. Prevent compacting rain garden BMPs by excluding construction equipment and foot traffic. Protect completed lawn and landscaped areas from compaction due to construction equipment. Control erosion and avoid introducing sediment from surrounding land uses onto permeable pavements. Do not allow muddy construction equipment on the base material or pavement. Do not allow sedimentladen runoff onto permeable pavements. Pavements fouled with sediments or no longer passing an initial infiltration text must be cleaned using procedures from the local stormwater manual or the manufacturer’s procedures. • Keep all heavy equipment off existing soils under LID facilities that have been excavated to final grade to retain the infiltration rate of the soils. 3.2 Site Specific BMPs Site specific BMPs are shown on the TESC Plan Sheets and Details in Appendix A. These site specific plan sheets will be updated annually. 3.3 Additional Advanced BMPs Construction Stormwater Chemical Treatment (BMP C 250) (implemented only with prior written approval from Ecology). Stormwater Pollution Prevention Plan 19 16836 IKEA SWPPP .doc Construction Stormwater Filtration (BMP C251) Filtration removes sediment from runoff originating from disturbed areas of the site. Traditional BMPs used to control soil erosion and sediment loss from sites under development may not be adequate to ensure compliance with the water quality standard for turbidity in the receiving water. Filtration may be used in conjunction with gravity settling to remove sediment as small as fine silt (0.5 µm). The reduction in turbidity will be dependent on the particle size distribution of the sediment in the stormwater. In some circumstances, sedimentation and filtration may achieve compliance with the water quality standard for turbidity. This element is included as an optional treatment consideration. Implementation maybe necessary should unforeseeable conditions or circumstances arise resulting in the need for alternate methods. This BMP is not intended to be applicable at this time. Unlike chemical treatment, the use of construction stormwater filtration does not require approval from Ecology. Filtration may also be used in conjunction with polymer treatment in a portable system to assure capture of the flocculated solids. Design and Installation Specifications – Background Information Filtration with sand media has been used for over a century to treat water and wastewater. The use of sand filtration for treatment of stormwater has developed recently, generally to treat runoff from streets, parking lots, and residential areas. The application of filtration to construction stormwater treatment is currently under development. Two types of filtration systems may be applied to construction stormwater treatment: rapid and slow. Rapid sand filters are the typical system used for water and wastewater treatment. They can achieve relatively high hydraulic flow rates, on the order of 2 to 20 gpm/sf, because they have automatic backwash systems to remove accumulated solids. In contrast, slow sand filters have very low hydraulic rates, on the order of 0.02 gpm/sf, because they do not have backwash systems. To date, slow sand filtration has generally been used to treat stormwater. Slow sand filtration is mechanically simple in comparison to rapid sand filtration but requires a much larger filter area. Filtration Equipment Stormwater Pollution Prevention Plan 20 16836 IKEA SWPPP .doc Sand media filters are available with automatic backwashing features that can filter to 50 µm particle size. Screen or bag filters can filter down to 5 µm. Fiber wound filters can remove particles down to 0.5 µm. Filters should be sequenced from the largest to the smallest pore opening. Sediment removal efficiency will be related to particle size distribution in the stormwater. Treatment Process Description Stormwater is collected at interception point(s) on the site and is diverted to a sediment pond or tank for removal of large sediment and storage of the stormwater before it is treated by the filtration system. The stormwater is pumped from the trap, pond, or tank through the filtration system in a rapid sand filtration system. Slow sand filtration systems are designed as flow through systems using gravity. If large volumes of concrete are being poured, pH adjustment may be necessary. Maintenance Standards Rapid sand filters typically have automatic backwash systems that are triggered by a pre-set pressure drop across the filter. If the backwash water volume is not large or substantially more turbid than the stormwater stored in the holding pond or tank, backwash return to the pond or tank may be appropriate. However, land application or another means of treatment and disposal may be necessary. Screen, bag, and fiber filters must be cleaned and/or replaced when they become clogged. Sediment shall be removed from the storage and/or treatment ponds as necessary. Removal is required once or twice during a wet season and at the decommissioning of the ponds Stormwater Pollution Prevention Plan 21 16836 IKEA SWPPP .doc 4.0 Construction Phasing and BMP Implementation The BMP implementation schedule will be driven by the construction schedule. The following provides a sequential list of the proposed construction schedule milestones and the corresponding BMP implementation schedule. The list contains key milestones such as wet season construction. The BMP implementation schedule listed below is keyed to proposed phases of the construction project, and reflects differences in BMP installations and inspections that relate to wet season construction. The project site is located west of the Cascade Mountain Crest. As such, the dry season is considered to be from May 1 to September 30 and the wet season is considered to be from October 1 to April 30. Estimate of Construction start date: 07/2015 Estimate of Construction finish date: 03/2016 Mobilize equipment on site: 07/2015 Mobilize and store all ESC and soil stabilization products: 07/2015 Install ESC measures: 07/2015 Install stabilized construction entrance: 08/2015 Begin clearing and grubbing: 09/2015 Stormwater Pollution Prevention Plan 22 16836 IKEA SWPPP .doc 5.0 Pollution Prevention Team 5.1 Roles and Responsibilities The pollution prevention team consists of personnel responsible for implementation of the SWPPP, including the following: Certified Erosion and Sediment Control Lead (CESCL) – primary contractor contact, responsible for site inspections (BMPs, visual monitoring, sampling, etc.); to be called upon in case of failure of any ESC measures. Resident Engineer – For projects with engineered structures only (sediment ponds/traps, sand filters, etc.): site representative for the owner that is the project's supervising engineer responsible for inspections and issuing instructions and drawings to the contractor's site supervisor or representative Emergency Ecology Contact – individual to be contacted at Ecology in case of emergency. Emergency Owner Contact – individual that is the site owner or representative of the site owner to be contacted in the case of an emergency. Non-Emergency Ecology Contact – individual that is the site owner or representative of the site owner than can be contacted if required. Monitoring Personnel – personnel responsible for conducting water quality monitoring; for most sites this person is also the Certified Erosion and Sediment Control Lead. 5.2 Team Members Names and contact information for those identified as members of the pollution prevention team are provided in the following table. Title Name(s) Phone Number Certified Erosion and Sediment Control Lead (CESCL) To be determined ~ Resident Engineer To be determined ~ Emergency Ecology Contact Southwest Regional Office DOE 1-360-407-6300 Emergency Owner Contact Lydia Gartrell, PE 650-387-6831 Stormwater Pollution Prevention Plan 23 16836 IKEA SWPPP .doc Non-Emergency Ecology Contact Clay Keown 360 407 6048 Monitoring Personnel To be determined ~ Stormwater Pollution Prevention Plan 24 16836 IKEA SWPPP .doc 6.0 Site Inspections and Monitoring Monitoring includes visual inspection, monitoring for water quality parameters of concern, and documentation of the inspection and monitoring findings in a site log book. A site log book will be maintained for all on-site construction activities and will include: A record of the implementation of the SWPPP and other permit requirements; Site inspections; and, Stormwater quality monitoring. For convenience, the inspection form and water quality monitoring forms included in this SWPPP include the required information for the site log book. This SWPPP may function as the site log book if desired, or the forms may be separated and included in a separate site log book. However, if separated, the site log book but must be maintained on-site or within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. 6.1 Site Inspection All BMPs will be inspected, maintained, and repaired as needed to assure continued performance of their intended function. The inspector will be a Certified Erosion and Sediment Control Lead (CESCL) per BMP C160. The name and contact information for the CESCL is provided in Section 5 of this SWPPP. Site inspection will occur in all areas disturbed by construction activities and at all stormwater discharge points. Stormwater will be examined for the presence of suspended sediment, turbidity, discoloration, and oily sheen. The site inspector will evaluate and document the effectiveness of the installed BMPs and determine if it is necessary to repair or replace any of the BMPs to improve the quality of stormwater discharges. All maintenance and repairs will be documented in the site log book or forms provided in this document. All new BMPs or design changes will be documented in the SWPPP as soon as possible. 6.1.1 Site Inspection Frequency Site inspections will be conducted at least once a week and within 24 hours following any discharge from the site. For sites with temporary stabilization measures, the site inspection frequency can be reduced to once every month if the site operator has successfully applied for inactive status for the site using the Permit Fee Activity Status Change Form, which can be found at the following web site. http://www.ecy.wa.gov/programs/wq/permits/permit_fees/ConstructionActivityStatusCha ngeForm.pdf Stormwater Pollution Prevention Plan 25 16836 IKEA SWPPP .doc 6.1.2 Site Inspection Documentation The site inspector will record each site inspection using the site log inspection forms provided in Appendix E. The site inspection log forms may be separated from this SWPPP document, but will be maintained on-site or within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. 6.2 Stormwater Quality Monitoring 6.2.1 Turbidity Sampling Monitoring requirements for the proposed project will include turbidity sampling to monitor site discharges for water quality compliance with the 2005 Construction Stormwater General Permit (Appendix D). Sampling will be conducted at all site discharge points at least once per calendar week. Turbidity monitoring will follow the analytical methodologies described in Section S4 of the 2005 Construction Stormwater General Permit (Appendix D). The key benchmark values that require action include 25 NTU and 250 NTU for turbidity. If the 25 NTU benchmark for turbidity is exceeded, the following steps will be conducted: 1. Ensure all BMPs specified in this SWPPP are installed and functioning as intended. 2. Assess whether additional BMPs should be implemented and make revisions to the SWPPP as necessary. 3. Sample the discharge location daily until the analysis results are less than 25 NTU (turbidity) or 32 cm (transparency). If the turbidity is greater than 25 NTU but less than 250 NTU for more than 3 days, additional treatment BMPs will be implemented within 24 hours of the third consecutive sample that exceeded the benchmark value. Additional treatment BMPs will include, but are not limited to, off-site treatment, infiltration, filtration and chemical treatment. If the 250 NTU benchmark for turbidity is exceeded at any time, the following steps will be conducted: 1. Notify Ecology by phone within 24 hours of analysis. 2. Continue daily sampling until the turbidity is less than 25 NTU. 3. Initiate additional treatment BMPs such as off-site treatment, infiltration, filtration and chemical treatment within 24 hours of the first 250 NTU exceedance. 4. Implement additional treatment BMPs as soon as possible, but within 7 days of the first 250 NTU exceedance. Stormwater Pollution Prevention Plan 26 16836 IKEA SWPPP .doc 5. Describe inspection results and remedial actions that are taken in the site log book and in monthly discharge monitoring reports. 6.2.2 pH Sampling Stormwater runoff will be monitored for pH starting on the first day of any activity that includes more than 40 yards of poured or recycled concrete, or after the application of “Engineered Soils” such as, Portland cement treated base, cement kiln dust, or fly ash. This does not include fertilizers. For engineered soils, the pH monitoring period begins when engineered soils are first exposed to precipitation and continue until the area is fully stabilized. Stormwater samples will be collected daily from all points of discharge from the site and measured for pH using a calibrated pH meter, pH test kit, or wide range pH indicator paper. If the measured pH is 8.5 or greater, the following steps will be conducted: 1. Prevent the high pH water from entering storm drains or surface water. 2. Adjust or neutralize the high pH water if necessary using appropriate technology such as CO2 sparging (liquid or dry ice). 3. Contact Ecology if chemical treatment other than CO2 sparging is planned. Stormwater Pollution Prevention Plan 27 16836 IKEA SWPPP .doc 7.0 Reporting and Recordkeeping 7.1 Recordkeeping 7.1.1 Site Log Book A site log book will be maintained for all on-site construction activities and will include: A record of the implementation of the SWPPP and other permit requirements; Site inspections; and, Stormwater quality monitoring. For convenience, the inspection form and water quality monitoring forms included in this SWPPP include the required information for the site log book. 7.1.2 Records Retention Records of all monitoring information (site log book, inspection reports/checklists, etc.), this Stormwater Pollution Prevention Plan, and any other documentation of compliance with permit requirements will be retained during the life of the construction project and for a minimum of three years following the termination of permit coverage in accordance with permit condition S5.C. 7.1.3 Access to Plans and Records The SWPPP, General Permit, Notice of Authorization letter, and Site Log Book will be retained on site or within reasonable access to the site and will be made immediately available upon request to Ecology or the local jurisdiction. A copy of this SWPPP will be provided to Ecology within 14 days of receipt of a written request for the SWPPP from Ecology. Any other information requested by Ecology will be submitted within a reasonable time. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with permit condition S5.G. 7.1.4 Updating the SWPPP In accordance with Conditions S3, S4.B, and S9.B.3 of the General Permit, this SWPPP will be modified if the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site or there has been a change in design, construction, operation, or maintenance at the site that has a significant effect on the discharge, or potential for discharge, of pollutants to the waters of the State. The SWPPP will be modified within seven days of determination based on inspection(s) that additional or modified BMPs are necessary to correct problems identified, and an updated timeline for BMP implementation will be prepared. Stormwater Pollution Prevention Plan 28 16836 IKEA SWPPP .doc 7.2 Reporting 7.2.1 Discharge Monitoring Reports If cumulative soil disturbance is 5 acres or larger: Discharge Monitoring Reports (DMRs) will be submitted to Ecology monthly. If there was no discharge during a given monitoring period, the Permittee shall submit the form as required, with the words “No discharge” entered in the place of monitoring results. The DMR due date is 15 days following the end of each month. 7.2.2 Notification of Noncompliance If any of the terms and conditions of the permit are not met, and it causes a threat to human health or the environment, the following steps will be taken in accordance with permit section S5.F: 1. Ecology will be immediately notified of the failure to comply. 2. Immediate action will be taken to control the noncompliance issue and to correct the problem. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. 7.2.3 Permit Application and Changes In accordance with permit condition S2.A, a complete application form will be submitted to Ecology and the appropriate local jurisdiction (if applicable) to be covered by the General Permit. Stormwater Pollution Prevention Plan 29 16836 IKEA SWPPP .doc Appendix A – Site Plans Stormwater Pollution Prevention Plan 30 16836 IKEA SWPPP .doc Stormwater Pollution Prevention Plan 31 16836 IKEA SWPPP .doc Stormwater Pollution Prevention Plan 33 16836 IKEA SWPPP .doc Stormwater Pollution Prevention Plan 36 16836 IKEA SWPPP .doc Appendix B – Construction BMPs Stake and Wire Fence (BMP C104) Stabilized Construction Entrance (BMP C105) Wheel Wash (BMP C106) Water Quality Pond or Vault Straw Bale Barrier (BMP C230) Silt Fence (BMP C233) Storm Drain Inlet Protection (BMP C220) Plastic Covering (BMP C123) Gradient Terraces (BMP C131) Check Dams (BMP C207) Mulching (BMP C121) Dust Control (BMP C140) Material Delivery, Storage and Containment (BMP C153) Concrete Handling (BMP C151) Concrete Washout Area (BMP C154) Materials On Hand (BMP C150) Certified Erosion and Sediment Control Lead (BMP C160) Scheduling (BMP C162) Appendix C – Alternative BMPs The following includes a list of possible alternative BMPs for each of the 12 elements not described in the main SWPPP text. This list can be referenced in the event a BMP for a Stormwater Pollution Prevention Plan 37 16836 IKEA SWPPP .doc specific element is not functioning as designed and an alternative BMP needs to be implemented. Element #1 - Mark Clearing Limits BMP C101: Preserving Natural Vegetation Element #2 - Establish Construction Access BMP C107 Construction Road/Parking Area Stabilization Element #3 - Control Flow Rates Element #4 - Install Sediment Controls Sediment Trap (BMP C240) Gravel Filter Berm (BMP C232) Temporary Sediment Pond (BMP C241) Advanced BMPs: BMP C250: Construction Stormwater Chemical Treatment Element #5 - Stabilize Soils BMP C121: Mulching BMP C122 Nets and Blankets BMP C124 Sodding BMP C126: Polyacrylamide (PAM) for Soil Erosion Protection Element #6 - Protect Slopes Element #8 - Stabilize Channels and Outlets Element #10 - Control Dewatering Additional Advanced BMPs to Control Dewatering: BMP C250: Construction Stormwater Chemical Treatment (implemented only with prior written approval from Ecology). BMP C251: Construction Stormwater Filtration Stormwater Pollution Prevention Plan 38 16836 IKEA SWPPP .doc Appendix D – General Permit Stormwater Pollution Prevention Plan 39 16836 IKEA SWPPP .doc Appendix E – Site Inspection Forms (and Site Log) The results of each inspection shall be summarized in an inspection report or checklist that is entered into or attached to the site log book. It is suggested that the inspection report or checklist be included in this appendix to keep monitoring and inspection information in one document, but this is optional. However, it is mandatory that this SWPPP and the site inspection forms be kept onsite at all times during construction, and that inspections be performed and documented as outlined below. At a minimum, each inspection report or checklist shall include: a. Inspection date/times b. Weather information: general conditions during inspection, approximate amount of precipitation since the last inspection, and approximate amount of precipitation within the last 24 hours. c. A summary or list of all BMPs that have been implemented, including observations of all erosion/sediment control structures or practices. d. The following shall be noted: i. locations of BMPs inspected, ii. locations of BMPs that need maintenance, iii. the reason maintenance is needed, iv. locations of BMPs that failed to operate as designed or intended, and v. locations where additional or different BMPs are needed, and the reason(s) why e. A description of stormwater discharged from the site. The presence of suspended sediment, turbid water, discoloration, and/or oil sheen shall be noted, as applicable. f. A description of any water quality monitoring performed during inspection, and the results of that monitoring. g. General comments and notes, including a brief description of any BMP r repairs, maintenance or installations made as a result of the inspection. h. A statement that, in the judgment of the person conducting the site inspection, the site is either in compliance or out of compliance with the terms and conditions of the SWPPP and the NPDES permit. If the site inspection indicates that the site is out of Stormwater Pollution Prevention Plan 40 16836 IKEA SWPPP .doc compliance, the inspection report shall include a summary of the remedial actions required to bring the site back into compliance, as well as a schedule of implementation. i. Name, title, and signature of person conducting the site inspection; and the following statement: “I certify under penalty of law that this report is true, accurate, and complete, to the best of my knowledge and belief”. When the site inspection indicates that the site is not in compliance with any terms and conditions of the NPDES permit, the Permittee shall take immediate action(s) to: stop, contain, and clean up the unauthorized discharges, or otherwise stop the noncompliance; correct the problem(s); implement appropriate Best Management Practices (BMPs), and/or conduct maintenance of existing BMPs; and achieve compliance with all applicable standards and permit conditions. In addition, if the noncompliance causes a threat to human health or the environment, the Permittee shall comply with the Noncompliance Notification requirements in Special Condition S5.F of the permit. Stormwater Pollution Prevention Plan 41 16836 IKEA SWPPP .doc Site Inspection Form General Information Project Name: Inspector Name: Title: CESCL # : Date: Time: Inspection Type: □ After a rain event □ Weekly □ Turbidity/transparency benchmark exceedance □ Other Weather Precipitation Since last inspection In last 24 hours Description of General Site Conditions: Inspection of BMPs Element 1: Mark Clearing Limits BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Element 2: Establish Construction Access BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Stormwater Pollution Prevention Plan 42 16836 IKEA SWPPP .doc Element 3: Control Flow Rates BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Element 4: Install Sediment Controls BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Stormwater Pollution Prevention Plan 43 16836 IKEA SWPPP .doc Element 5: Stabilize Soils BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Element 6: Protect Slopes BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Stormwater Pollution Prevention Plan 44 16836 IKEA SWPPP .doc Element 7: Protect Drain Inlets BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Element 8: Stabilize Channels and Outlets BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Stormwater Pollution Prevention Plan 45 16836 IKEA SWPPP .doc Element 9: Control Pollutants BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Element 10: Control Dewatering BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Stormwater Discharges From the Site Observed? Problem/Corrective Action Y N Location Turbidity Discoloration Sheen Location Turbidity Discoloration Sheen Stormwater Pollution Prevention Plan 46 16836 IKEA SWPPP .doc Water Quality Monitoring Was any water quality monitoring conducted? □ Yes □ No If water quality monitoring was conducted, record results here: If water quality monitoring indicated turbidity 250 NTU or greater; or transparency 6 cm or less, was Ecology notified by phone within 24 hrs? □ Yes □ No If Ecology was notified, indicate the date, time, contact name and phone number below: Date: Time: Contact Name: Phone #: General Comments and Notes Include BMP repairs, maintenance, or installations made as a result of the inspection. Were Photos Taken? □ Yes □ No If photos taken, describe photos below: Stormwater Pollution Prevention Plan 47 16836 IKEA SWPPP .doc Appendix F – Engineering Calculations Tab 9.0 16836.006.doc 9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT The Site Improvement Bond Quantity Worksheets are provided in this section. Tab 10.0 16836.006.doc 10.0 OPERATIONS AND MAINTENANCE MANUAL The KCSWDM Appendix A maintenance checklists and the Filterra Maintenance Manual are included in this section. Also included in this section is the Declaration of Covenant Prohibiting Use of Leachable Metals.