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Stormwater Form and Drainage Report
002014003 RAMAGE RESIDENCE 552,464 12.68 ~100 5228 ~3600 3384 0 ~4000 4008 ~20,320 146 547 5228 300 200 0 2884 0 0 0 0 0 0 8612 8612 0 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Ramage Residence 750 MCMINN RD PORT TOWNSEND, WA Parcel #: 002014003 Owners: RAMAGE, RICHARD 206-345-2792 Permit #s: PRE2022-00042 © Rebecca Scott Vader, PE 6817 27th ST W, #65353 University Place, WA 98464 253-363-2065 info@vaderengineering.com DRAINAGE CONTROL REPORT 2045 Ramage | ii VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Page inserted for double-sided printing 2045 Ramage | iii VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com This page inserted for print spacing. 2045 Ramage | iv VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com TABLE OF CONTENTS OVERVIEW .................................................................................................................................... 6 1. EXISTING SITE CONDITIONS ................................................................................................ 6 2. PROJECT DESCRIPTION: .................................................................................................... 11 3. OFFSITE ANALYSIS ........................................................................................................... 13 TASK 1: STUDY AREA DEFINITIONS AND MAPS ................................................................................... 13 TASK 2: RESOURCE REVIEW ........................................................................................................... 13 TASK 3: FIELD INSPECTION ............................................................................................................. 13 TASK 4: DOWNSTREAM DRAINAGE SYSTEM DESCRIPTION AND EXISTING AND POTENTIAL PROBLEMS ............. 13 TASK 5: MITIGATION OF EXISTING OR POTENTIAL PROBLEMS ................................................................ 13 4. DETERMINE APPLICABLE MINIMUM REQUIREMENTS ...................................................... 15 MINIMUM REQUIREMENT #1: PREPARATION OF STORMWATER SITE PLANS ...................... 16 MINIMUM REQUIREMENT #2: CONSTRUCTION STORMWATER POLLUTION PREVENTION (SWPPP) ................................................................................................................................ 16 MINIMUM REQUIREMENT #3: SOURCE CONTROL OF POLLUTION ....................................... 16 MINIMUM REQUIREMENT #4: PRESERVATION OF NATURAL DRAINAGE SYSTEM ................ 16 MINIMUM REQUIREMENT #5: ON-SITE STORMWATER MANAGEMENT ................................ 16 MINIMUM REQUIREMENT #6: RUNOFF TREATMENT ............................................................ 16 MINIMUM REQUIREMENT #7: FLOW CONTROL .................................................................... 16 MINIMUM REQUIREMENT #8: WETLANDS PROTECTION ...................................................... 16 MINIMUM REQUIREMENT #9: OPERATION AND MAINTENANCE ........................................... 16 OPTIONAL GUIDANCE #1: FINANCIAL LIABILITY.................................................................... 16 OPTIONAL GUIDANCE #2: OFFSITE ANALYSIS AND MITIGATION ............................................ 17 5. SELECT PERMANENT STORMWATER CONTROLS ............................................................. 17 STEP I: DETERMINE AND READ THE APPLICABLE MINIMUM REQUIREMENTS ............................................. 17 6. CSWPPP TEMPORARY EROSION AND SEDIMENT CONTROL ANALYSIS AND DESIGN ......... 21 7. REPORT ON PROJECT ........................................................................................................ 23 8. CHECK COMPLIANCE WITH APPLICABLE MINIMUM REQUIREMENTS. ................................................ 23 APPENDIX A: STORMWATER SITE PLANS..................................................................................... 24 APPENDIX B MINIMUM REQUIREMENT #2: CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN (CSWPPP) ..................................................................................................... 25 ELEMENT 2: ESTABLISH CONSTRUCTION ACCESS .................................................................... 26 ELEMENT 3: CONTROL FLOW RATES ....................................................................................... 27 ELEMENT 4: INSTALL SEDIMENT CONTROLS ........................................................................... 27 ELEMENT 5: STABILIZE SOILS ................................................................................................... 28 ELEMENT 6: PROTECT SLOPES ................................................................................................. 29 ELEMENT 7: PROTECT DRAIN INLETS ....................................................................................... 29 ELEMENT 8: STABILIZE CHANNELS AND OUTLETS ................................................................... 30 2045 Ramage | v VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com ELEMENT 9: CONTROL POLLUTANTS ....................................................................................... 30 ELEMENT 10: CONTROL DE-WATERING .................................................................................. 31 ELEMENT 11: MAINTAIN BMP’S .............................................................................................. 31 ELEMENT 12: MANAGE THE PROJECT ..................................................................................... 31 SAMPLE SITE INSPECTION FORM ..................................................................................................... 36 APPENDIX C SOILS INFORMATION............................................................................................... 43 APPENDIX D CALCULATIONS ....................................................................................................... 45 CONVEYANCE ......................................................................................................................... 45 INFILTRATION ......................................................................................................................... 53 LIST OF APPENDICES Appendix A – Stormwater Site Plans Appendix B – Construction Stormwater Pollution Prevention Plan (SWPPP) Appendix C – Soils Report TABLE OF FIGURES Figure 1 – Vicinity Map .................................................................................................................. 8 Figure 2 – Basin Map .................................................................................................................... 9 Figure 3 – Map of Streams, Wetlands, and Floodplains .............................................................. 10 Figure 4 – Site Development Plan ............................................................................................... 12 Figure 5: Downstream Map GIS Terrain ...................................................................................... 14 Figure 6: Downstream Map Milton Public Works ....................................................................... 14 Figure 7 – DOE SMMWW: Minimum Requirements for New Development ............................... 15 Figure 8 – DOE SMMWW: Flow Chart for LID MR #5 Requirements ........................................... 18 Figure 9 – NOAA Isopluvial 100 year rainfall intensity ................................................................ 50 Figure 10 – Precipitation Map 2 year rainfall intensity................................................................ 51 Figure 11 –Precipitation Map 25 year rainfall intensity .............................................................. 52 Figure 12 –Project TESC Plan ....................................................................................................... 22 2045 Ramage |6 Vader ENGINEERING 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com OVERVIEW This Storm Drainage Report is submitted as supporting documentation for all permits required by the for the construction of the proposed Project. This analysis is completed using the format set forth in the 2019 Department of Ecology (DOE) Stormwater Management Manual. The format lays out the design processes, and the final step is this document. Step 1: Site Analysis: Collect and Analyze Information on Existing Conditions. Step 2: Prepare Preliminary Development Layout. Step 3: Perform Offsite Analysis. Step 4: Determine the Applicable Minimum Requirements. Step 5: Select Permanent Stormwater Controls. Step 6: Prepare CSWPPP. Step 7: Report on Project. Step 8: Check Compliance with Applicable Minimum Requirements. The facilities are designed in accordance with the County of Jefferson County Standards Section JCC 18.30.070 of the Unified Development Code (UDC). LID is the preferred and commonly- used approach to site development. 1. EXISTING SITE CONDITIONS Please refer to Figure 1 – 3, following, to aid in the description. The existing property is undeveloped with McMinn Road, an existing private access gravel road, crossing the southeast corner of the site. The property is restricted to the north by the state waterbody, Strait of Juan de Fuca, and bordered by rural residential zone properties on the south, west, and east sides of the property. The properties west and east of the property are developed, whereas the property south of the property is undeveloped and owned by the same owner of this property at the time of this report. This site is within a waterfront property adjacent to the Strait of Juan de Fuca and includes a 200-foot Shoreline Buffer. The property is within a shoreline slope stability area, landslide hazard area, and seismic hazard area. Additionally, the site is also within a critical aquifer recharge area, and within a saltwater intrusion protection zone. There are no other notable 2045 Ramage | 7 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com critical areas identified. The basin is geologically within the Discovery Bay drainage basin, within the greater Strait of Juan de Fuca Drainage and Salish Sea basins. Stormwater does not enter the site in significant volumes, and stormwater that exits the site appears to infiltrate or sheet flow northerly and discharges directly to the Strait of Juan de Fuca. More detail is shown in the Offsite Analysis section. The following tabulates the existing site data: Addresses: 750 McMinn Rd Parcel Number: 002014003 Site Area (Clearing Limits) 20,320 SF (0.47 AC) Total Site (Property Limits) 552,464 SF (12.68 AC) Impervious Area: 8,612 SF Zoning: R-R5 Rural Residential Soils (See Appendix): Cmc Clallam gravelly sandy loam 0-15% Co Costal beaches 2045 Ramage | 8 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Figure 1 – Vicinity Map Property, Roads, Geographic Areas 2045 Ramage | 9 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Figure 2 – Basin Map Discovery Bay Basin Site 2045 Ramage | 10 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Figure 3 – Map of Streams, Wetlands, and Floodplains Site 2045 Ramage | 11 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com 2. PROJECT DESCRIPTION: Please refer to Figure 4 – Site Development Plan to aid in the project description and show the development layout. The project is intended to build a new residence, detached garage, concrete drive and parking area, including new landscaping and private utilities. In addition to the improvements inside the building, the project will include exterior grading and drainage improvements. TABLE SUMMARIZING STORMWATER AREAS Basin ID Drains From Drains To Future Discharge flow Length to Facility Basin: 1 Site Shoreline No Change None (Direct) Description Current SF Proposed SF New Total SF Site Area (Clearing Limits) 20,320 - - Hard Surfaces 0 3,384 Conc. Drive 5,228 Roofs _______________ SubTotal 8,612 8,612 -Subset added in previous 5 years 0 - - -Subset that is Pollution- Generating Impervious Surface 0 5,228 5,228 -Subset that is Effective Impervious surface 0 0 (100% infiltrated) 0 (100% infiltrated) Disturbed Pervious surface - 11,708 11,708 Converted Vegetation Area - 0 0 Undisturbed Area protected - 532,144 532,144 Value of additions or remodels in the last 5 years. N/A Valuation Not used as basis for exemptions. 2045 Ramage | 12 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Figure 4 – Site Development Plan N 2045 Ramage | 13 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com 3. OFFSITE ANALYSIS Task 1: Study Area Definitions and Maps Please refer to Figures above to aid in the description of the Offsite Analysis. The study area was not able to be extended to 0.25 miles downstream as it directly discharges to marine waters. It did not have upstream conditions to study due to terrain and the built environment. Task 2: Resource Review The following resources and documents were reviewed in preparing this analysis. Pertinent excerpts from these resources have been included in this study. 1. Jefferson County GIS Mapping, Public Land Records. 2. Survey (Boundary) from Informed Land Survey. 3. Survey (Topographical) from Johnston Land Survey. 4. NRCS Web Soil Survey of approximate site location. 5. Geotechnical Reports from South Sound Geotechnical Consulting. Task 3: Field Inspection Field inspection was performed by a representative of Vader Engineering on 2-6-23. Observations were in keeping with the findings on the County of Jefferson records. There were no apparent deficiencies in the downstream conveyances. Task 4: Downstream Drainage System Description and Existing and Potential Problems Please see Figures 5 and 6 to aid in the following description. No drainage issues are known to exist within the site area. There is no existing public storm system in the area. There is no upstream or downstream drainage system and site runoff generally infiltrations or sheet flows to the adjacent shoreline. The property south is undeveloped where native vegetation retains runoff whereas the properties west and east of the site are fully developed and are conveyed separately. Task 5: Mitigation of Existing or Potential Problems No drainage issues are anticipated from this proposed development if built to plan and maintained. 2045 Ramage | 14 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Figure 5: Downstream Map GIS Terrain Figure 6: Downstream Map: Stormwater Infrastructure N/A see Figure 5 N/A – See Figure 5 Downstream Runoff: Sheet Flow Strait of Juan de Fuca (saltwater) Site Property Line 2045 Ramage | 15 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com 4. DETERMINE APPLICABLE MINIMUM REQUIREMENTS Figure 7- Flow Chart for Determining Requirements displays the applicable design analysis for the project. Figure 7 – DOE SMMWW: Minimum Requirements for New Development 2045 Ramage | 16 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com A. MINIMUM REQUIREMENTS SUMMARY MINIMUM REQUIREMENT #1: Preparation of Stormwater Site Plans A set of Stormwater Site Plans is included in Appendix A of this report. MINIMUM REQUIREMENT #2: Construction Stormwater Pollution Prevention (SWPPP) A Construction SWPPP is included in Appendix B of this report. MINIMUM REQUIREMENT #3: Source Control of Pollution Source control for ongoing Operations and Maintenance is addressed in Section 6. MINIMUM REQUIREMENT #4: Preservation of Natural Drainage System Stormwater from the site drain to the north, infiltrating or sheet flowing across the property, then discharging directly into the saltwater body of Strait of Juan de Fuca which matches existing conditions. MINIMUM REQUIREMENT #5: On-site Stormwater Management This project uses Table 1-3.1 to determine On-Site Stormwater Management BMPs., which allows a project to choose any flow control BMP if the project is outside the UGA and on a parcel 5 acres or larger. Please refer to the LID Section of this report, below. MINIMUM REQUIREMENT #6: Runoff Treatment With less than 5,000 SF of pollution-generating hard surface (PGHS), treatment is not required. MINIMUM REQUIREMENT #7: Flow Control The site is statutorily exempt due to discharge to marine waters, but practically this is difficult. An infiltration trench is proposed to capture and fully infiltrate 100% of impervious surface area run-off flows which addresses the flow control requirement. Please refer to the Flow Control Section of this report, below. MINIMUM REQUIREMENT #8: Wetlands Protection Not Applicable – No potential wetlands per Figure 3. MINIMUM REQUIREMENT #9: Operation and Maintenance Stormwater Operations are described in the Maintenance Manual included in Appendix D. A sample log of actions is provided. This is to be kept onsite or in reasonable access to the site and transferred with the property to future owners. OPTIONAL GUIDANCE #1: Financial Liability Bond and liability assurances will be provided by the Proponent or a representative of the Proponent (Contractor) prior to start of construction if required by the jurisdiction. The owner will be responsible for on-going cost of private maintenance. 2045 Ramage | 17 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com OPTIONAL GUIDANCE #2: Offsite Analysis and Mitigation Projects that discharge off site must address potential impacts to water quality, erosion, slope stability and drainage impacts, and propose mitigation for predicted impacts. Please refer to Section 3 of this report for assessment of potential and Section 5 for proposed mitigation, if needed. 5. SELECT PERMANENT STORMWATER CONTROLS This section addresses the analysis and design of the drainage flow controls and water quality measures. Selection of Flow Control Facilities starts by: • Following the LID Flow chart to determine the required list, then • Following the priority listings for that LID List and analyzing the infeasibility criteria to determine the first feasible BMP for each of 3 surface types. o Once a BMP is selected it is sized. o Placed on the design drawings. o No other On-site Stormwater LID BMPS is necessary for that surface. • Apply any LID credits generated toward o Flow control (peak and/or duration matching). o Treatment design (basic or enhanced). Additional analysis of components such as the conveyance system, and in cases with potential for high groundwater, buoyancy resistance, are also addressed in this section. Step I: Determine and Read the Applicable Minimum Requirements The Flow Chart for LID requirements, below, indicates that this project is to follow List #2. 2045 Ramage | 18 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com The selection of Flow Control Facilities is made by following the priority listings for LID List #1 and analyzing the infeasibility criteria to determine the first feasible BMP for each of 3 surface types. Once a BMP is selected it is sized and placed, on the design drawings. No other On-site Stormwater Management BMP is necessary for that surface. Figure 8 – DOE SMMWW: Flow Chart for LID MR #5 Requirements 2045 Ramage | 19 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Feasibility is determined by evaluation against the design criteria, limitations, and infeasibility criteria identified for each BMP in the DOE manual; and the Competing Needs Criteria listed in Chapter V-5 - On-Site Stormwater Management. B. Onsite Stormwater Management Table 1-3.1: Minimum Requirement #5 Compliance Options for Projects Triggering Minimum Requirements #1 through #9 Surfaces and their BMPs Feasibility Analysis Lawn and landscaped areas: Post-Construction Soil Quality and Depth in accordance with BMP T5.13: Post- Construction Soil Quality and Depth. BMP T5.13 Post-Construction Soil Quality and Depth to be provided for disturbed pervious area – See notes on Stormwater Plan C4. Feasible, Selected. Roofs: Full Dispersion in accordance with BMP T5.30: Full Dispersion This BMP allows for "fully dispersing" runoff from impervious surfaces and cleared areas of development sites that protect at least 65% of the site (or a threshold discharge area on the site) in a forest or native condition. Insufficient space due to proximity to Slope Stability Hazard and Landslide Hazard area setbacks, Infeasible. Downspout Full Infiltration Systems in accordance with BMP T5.10A: Downspout Full Infiltration Downspouts may infiltrate or discharge. For LID analysis: Selected for all roof areas, Feasible. Rain Gardens in accordance with BMP T5.14A: Rain Gardens, or Bioretention in accordance with BMP T7.30: Bioretention Cells, Swales, and Planter Boxes. All roof surfaces managed. Downspout Dispersion Systems in accordance with BMP T5.10B: Downspout Dispersion Systems All roof surfaces managed. 2045 Ramage | 20 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Perforated Stub-out Connections in accordance with BMP T5.10C: Perforated Stub-out Connections All roof surfaces managed. Other Hard Surfaces: Full Dispersion in accordance with BMP T5.30: Full Dispersion Protected native vegetation area of 65% of site must be available. Insufficient space due to proximity to Slope Stability Hazard and Landslide Hazard area setbacks, Infeasible. Since any BMPs can be used when achieving performance standard, use Infiltration Infiltration capacity and minimum depth to season high groundwater layer. Selected for all non-roof areas, Feasible. Permeable pavement1 in accordance with BMP T5.15: Permeable Pavements, or Rain Gardens in accordance with BMP T5.14A: Rain Gardens, or Bioretention in accordance with BMP T7.30: Bioretention Cells, Swales, and Planter Boxes. All non-roof surfaces managed. Sheet Flow Dispersion in accordance with BMP T5.12: Sheet Flow Dispersion, All non-roof surfaces managed. Concentrated Flow Dispersion in accordance with BMP T5.11: Concentrated Flow Dispersion. All non-roof surfaces managed. Collect and Convey All non-roof surfaces managed. The overall sizes of the selected BMPs were based on the calculation shown in Appendix D. The total size was divided into constructable increments determined by the need to observe physical constraints and setbacks. C. CONVEYANCE SYSTEM ANALYSIS AND DESIGN For the new conveyance system connecting roof downspouts to the proposed infiltration trench, 6” pipe was selected as the minimum size residential site conveyance pipe. Please see the Cacluation in appendix D for confirmation that the pipe size is adequate for the projected peack flows. 2045 Ramage | 21 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com 6. CSWPPP TEMPORARY EROSION AND SEDIMENT CONTROL ANALYSIS AND DESIGN Please refer to Figure 9, TESC Plan, below, and Appendix B – Construction SWPPP of this report for the full details of the Temporary Erosion and Sediment Control Plan for the construction period. Erosion and Sedimentation Control Analysis and Design Less than an acre of disturbance is anticipated for this project. Proposed temporary measures possible for this project will include the following BMP’s: • Filter fences, and/or Straw Wattles for perimeter protection. • Retention of vegetated strips. • Straw mulch, hydroseed or other mulching and planting method to stabilize unworked areas. • Temporary drainage swales and rock check dams to drain slopes. Pollution Prevention and Spill Control Basic construction activities that will occur during this project will be subject to preventative measures to avoid impacting stormwater. For activities that go beyond the measures presented in Appendix B, one reference work for particular prevention and control measures is the King County Construction Stormwater Pollution Prevention and Spill Control Standards. 2045 Ramage | 22 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Figure 9 –Project TESC Plan 2045 Ramage | 23 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com 7. REPORT ON PROJECT A. SPECIAL REPORTS AND STUDIES Geotechnical Engineering Report by South Sound Geotechnical Consulting. Updated Geotechnical Engineering Report by Georesources Septic Design by Quayle Septic Designs OTHER PERMITS None that establish more stringent drainage control are known at this time. B. BOND QUANTITIES, FACILITY SUMMARIES AND DECLARATION OF COVENANT Bond and liability assurances will be provided by the representative of the Developer (Contractor) prior to start of construction. 8. Check Compliance with Applicable Minimum Requirements. Compliance checks are made by the jurisdiction at submittal, and by the Erosion Control Lead and Inspector during the construction of the design. 2045 Ramage | 24 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Appendix A: Stormwater Site Plans Please see the drawing sheets, attached by reference. 2045 Ramage | iii VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Stormwater Site Plan (SSP) (“Drainage Report”) Ramage Residence 750 MCMINN RD PORT TOWNSEND, WA Parcel(s): 002014003 Permit No: PRE2022-00042 Permit Application June 30, 2023 Revised , 20__ Approved ______, 20__ © Vader Engineering, LLC The following report has been prepared in conformance with sound engineering principles and standards, with the best available site and technical information at the time of investigation. The report contained herein has been prepared by the undersigned Professional Engineer(s) Licensed in the State of Washington. Rebecca Scott Vader, PE NAVD 88 (PER JC GIS)CONTOUR INTERVAL = 2'THE BASIS OF BEARING IS N88°29'21"W FROM IRON PIPE ATS.E. CORNER SEC. 1 AND REBAR & CAP SET BY EE ANDERSONPER PRELIMINARY ALTA SURVEY PERFORMED BY INFORMEDLAND SURVEY AND TOPOGRAPHIC SURVEY PERFORMED BYJOHNSTON LAND SURVEYINGBASIS OF BEARINGSVERTICAL DATUM0100501" = 100'200URBAN ZONECLASSIFICATIONBUILDING SETBACKSMINIMUM BUILDING SETBACK (FEET)FRONT-ARTERIALINTERIOR/SIDEREARR-R5RURALRESIDENTIAL5 (12)5 (12)20MEADOW RDPOND RD McMINN RD12. THE SPECIAL SIDE AND REAR SETBACKS PROVIDED IN TABLE 6-1 SHALL ALSO APPLY TO OUTBUILDINGS FOR RESIDENTIAL OR AGRICULTURAL USES SUCH ASDETACHED GARAGES, STORAGE SHEDS OR TOOL SHEDS, EXCEPT FOR EXISTINGLOTS OF RECORD LESS THAN FIVE ACRES WHEREIN THE MINIMUM REAR AND SIDEYARD SETBACKS FOR OUTBUILDINGS SHALL BE FIVE FEET. ENGINEERING BEFORE YOU DIGCALL1-800-424-5555NOT LESS THAN 48 HOURS BEFOREBEGINNING EXCAVATION WHERE ANYUNDERGROUND UTILITIES MAY BE LOCATED.SITE ADDRESS: COVER SHEET 750 - Mc MINN RD PORT TOWNSEND, WA 98368PARCEL NO. 002121003THE EAST HALF OF THE WEST HALF OF THE NORTHEAST QUARTER OF THENORTHEAST QUARTER OF SECTION 12; ALSO,PARCEL NO. 002014003THAT PORTION OF GOVERNMENT LOT 1 IN SECTION 1, LYING BETWEEN THE EASTAND WEST LINES OF SAID EAST HALF OF THE WEST HALF OF THE NORTHEASTQUARTER OF THE NORTHEAST QUARTER OF SAID SECTION 12 EXTENDED NORTHTO THE NORTH BOUNDARY OF SAID LOT 1;ALL IN TOWNSHIP 30 NORTH, RANGE 2 WEST, W.M.;ALL SITUATE IN THE COUNTY OF JEFFERSON, STATE OF WASHINGTONSUBJECT TO:NON-EXCLUSIVE EASEMENT FOR THE PURPOSE OF INGRESS, EGRESS ANDUTILITIES RECORDED UNDER AUDITOR'S FILE NO. 225050PROJECT INFOOWNER:GELERT R RAMAGE lll7051 - LINCOLN PKWY SW UNIT ESEATTLE, WA 98136-3005TEL:SHEET C1SHEET C2SHEET C3SHEET C4SHEET C5SHEET C6SHEET C7SHEET INDEXCIVIL ENGINEER:VADER ENGINEERING6817 27TH ST. W #65353TACOMA, WA 98464TEL: 253-363-2065COVER SHEETCSWPPP PLANCSWPPP NOTES & DETAILSCSWPPP NOTES & DETAILS (2)GRADING & STORM DRAINAGE PLANGRADING & STORM DRAINAGE NOTES & DETAILSGRADING & STORM DRAINAGE NOTES LEGAL DESCRIPTIONPARCEL NOS: 002121003, 002014003ADDRESS: 750 - Mc MINN RD PORT TOWNSEND, WATOTAL SITE AREA = 552,464 SQ. FT. (12.68 ACRES)SEWER: PRIVATE (SEPTIC)WATER: PRIVATE (WELL)SCHOOL DISTRICT: SD #50FIRE DISTRICT: FPD #1TELEPHONE :POWER: PUD #1ZONING: (R-R5) RURAL RESIDENTIALSITE DATACLEARING LIMITS130BMP 235 WATTLESEXISTING CONTOURPROPOSED CONTOURARCHITECT:HAYNE ARCHITECTSP.O. BOX 39MALIBU, CA 90265TEL: 310-456-0050PROPOSED YARD DRAINEX. ASPHALTEX. GRAVELSYMBOL LEGENDEX. HOG WIRE FENCE1.PRELIMINARY ALTA/NSPS LAND TITLE SURVEY PERFORMED BY INFORMEDLAND SURVEY, DATED 12/22/20202.TOPOGRAPHIC SURVEY PERFORMED BY JOHNSTON LAND SURVEYING,DATED 9/26/2022RECORDS OF JEFFERSON COUNTY AUDITOR'S OFFICESURVEY REFERENCESEX. COMMUNICATIONSEX. POWERPROPOSED STORM DRAINAGE LINESHORELINE160 (150' + 10')SURVEYOR: (BOUNDARY)INFORMED LAND SURVEYPO BOX 5137TACOMA, WA 98415TEL: 253-627-2070SURVEYOR: (TOPOGRAPHY)JOHNSTON LAND SURVEYPO BOX 158CARLSBORG, WA 98324TEL: 360-460-8539GEOTECHNICAL ENGINEER:GEO RESOURCES4809 PACIFIC HWY. E.FIFE, WA 98424TEL: 253-896-1011PUMA SHORT PLAT,RECORDING NO. 234018TOP OF REBAR & CAP AT FENCE CORNEREL.= 137.73ELEVATION ASSUMED VERTICAL DATUM PER JOHNSTON LAND SURVEYINGTOPOGRAPHIC MAP DATED 11-15-2022SITE BENCHMARKFOUND SECTION CORNER (AS SHOWN) SET REBAR & CAP EMW LS #44651 FOUND REBAR & CAP (AS SHOWN) FOUND IRON PIPE (AS SHOWN) (R1)HILDEBRANDT SHORT PLAT,RECORDING NO. 290533(R2)PROPOSED SEPTIC LINEPROPOSED CONCRETE GARAGE700 SQ FTFF=136.5EX. GRAVEL PRIVATEACCESS TO REMAINEX. ASPHALTPUBLIC ROADTO REMAINEX. FENCE TO REMAIN(TYPICAL)PROTECTEXISTING SHEDPROPERTY LINE(TYP.)PROPERTYLINEPRIMARY DRAINFIELDDESIGN BY OTHERSRESERVE DRAINFIELDDESIGN BY OTHERSRESERVE DRAINFIELD DESIGN BYOTHERSPROPOSED WELLDESIGN BY OTHERSEX. COMMUNICATION TOREMAINEX. POWER TO REMAINPROPOSEDPRIVATE WATERSS 6" PVCIE: 132.00 (MIN.)SS 6" PVC IE: 130.50 (MAX.)SS 6" PVCIE: 130.50 (MAX.)PROPERTY LINE(TYP.)100' WELLPROTECTIONRADIUSSS 6" PVCIE: 132.00 (MIN.)HOUSE3324 SQ FTFF=137.518.3' 21.2'5BMP 123STOCKPILED TOPSOIL/COMPOSTING ANDBMP 120 SEEDING WITHIN CLEARING LIMITS UNLESSOTHERWISE SHOWN555BMP C105CONSTRUCTION ENTRANCE AND/ORSTABILIZED CONSTRUCTION ENTRANCEPERC312EXISTING TRAIL ROUTETO BE RESTOREDC32C33248LF BMP 233 FILTER FABRIC FENCE OR BMP 235STRAW WATTLES PERCLEARING LIMITS22,387 SQ. FT.144366620.5'10'7738.1'37.9'38.1'37.9'39.3'31.9'21.9'SITE BENCHMARKTOP OF REBAR & CAPN: 5027.0659'E: 4980.1555'EL.= 137.7360'21.6'71.5'48.7'198LF BMP C200 INTERCEPTOR DIKE AND SWALESEE NOTE SHEET C3 BMP C200 INSTALL ROCK CHECK DAMSPERC3450LF BMP C200 INTERCEPTOR DIKE AND SWALESEE NOTE SHEET C3 BMP C200 INSTALL ROCK CHECK DAMSPERC34EXISTING TRAILTO REMAINDO NOT PARK, DRIVE, OR STAGE CONSTRUCTIONMATERIALS ON DRAIN FIELD AREAS (TYPICAL)020101" = 20'40 ENGINEERING BEFORE YOU DIGCALL1-800-424-5555NOT LESS THAN 48 HOURS BEFOREBEGINNING EXCAVATION WHERE ANYUNDERGROUND UTILITIES MAY BE LOCATED.SITE ADDRESS: CSWPPP PLAN 750 - Mc MINN RD PORT TOWNSEND, WA 98368TOTAL SITE.........................................................552,464 SQ. FT. ( 12.68 ACRES)CLEARING LIMITS.................................................20,320 SQ. FT.PROPOSED ROOF..................................................5,228 SQ. FT.PROPOSED CONCRETE........................................3,384 SQ. FT.LOT AREAS146 CU. YDS. - CUT547 CU. YDS. - FILL401 CU. YDS. NET - FILLNOTE:CUTS AND FILLS ARE PROVIDED FOR PERMITPURPOSES ONLY. CONTRACTOR SHALL MAKEHIS OWN DETERMINATION AS TO NECESSARYCUT AND FILL QUANTITIES.CUT & FILLS:1.MARK CLEARING/GRADING LIMITS2.CALL BUILDING INSPECTOR TO INSPECT CLEARING/GRADING LIMITS3.INSTALL INITIAL EROSION CONTROL PRACTICES (CONSTRUCTION ENTRANCE, SILTFENCE, CATCH BASIN INSERTS)4.CLEAR, GRADE AND FILL SITE AS OUTLINED IN THE SITE PLAN WHILE IMPLEMENTINGAND MAINTAINING TEMPORARY EROSION AND SEDIMENT CONTROL PRACTICES ATTHE SAME TIME5.INSTALL PERMANENT EROSION PROTECTION (IMPERVIOUS SURFACE,LANDSCAPING, ETC.)6.CONTACT BUILDING INSPECTOR FOR APPROVAL OF PERMANENT EROSIONPROTECTION AND SITE GRADES7.REMOVE EROSION CONTROL METHODS AS PERMITTED BY THE BUILDINGINSPECTOR AND REPAIR PERMANENT EROSION PROTECTION AS NECESSARY8.MONITOR AND MAINTAIN PERMANENT EROSION PROTECTION UNTIL SITE IS FULLYESTABLISHEDCSWPPP CONSTRUCTION SEQUENCE1.CLEARING & GRADING LIMITS2.STABILIZE ENTRANCE & CIRCULATION3.PREVENT SEDIMENTATION OF INFILTRATION FACILITIES, BMP C235 WATTLES (N/A)4.SEDIMENT CONTROLS BMP C235 WATTLES AND STABILIZE SOILS, BMP C120-126, 140WHERE SOIL DISTURBANCE WHERE SOIL DISTURBANCE IS UPGRADIENT OF ADJACENTPROPERTY OR DISPERSION OR INFILTRATION FACILITY AND BMP C234 VEGETATEDSTRIP IS NOT AVAILABLECSWPPP NOTES & KEY5. PROTECT SLOPES, BMP C120, 121, STOCKPILE SLOPES BMP C122, 1236. PROTECT DRAIN INLETS, BMP C2207. PROTECT CHANNELS PROPOSED8. MAINTAIN BMPS, INSPECT WEEKLY. REMOVE TEMPORARY BMPS WITHIN 30 DAYS OFFINAL STABILIZATION, BMP C160NAVD 88 (PER JC GIS)CONTOUR INTERVAL = 2'THE BASIS OF BEARING IS N88°29'21"W FROM IRON PIPE AT S.E. CORNER SEC. 1 AND REBAR &CAP SET BY EE ANDERSON PER PRELIMINARY ALTA SURVEY PERFORMED BY INFORMED LANDSURVEY AND TOPOGRAPHIC SURVEY PERFORMED BY JOHNSTON LAND SURVEYINGBASIS OF BEARINGSVERTICAL DATUM ENGINEERING BEFORE YOU DIGCALL1-800-424-5555NOT LESS THAN 48 HOURS BEFOREBEGINNING EXCAVATION WHERE ANYUNDERGROUND UTILITIES MAY BE LOCATED.SITE ADDRESS: CSWPPP NOTES & DETAILS 750 - Mc MINN RD PORT TOWNSEND, WA 98368 1.THE CONTRACTOR SHALL INSTALL AND MAINTAIN TEMPORARY SILT FENCES AT THE LOCATIONS SHOWN IN THE PLANS.2.CONSTRUCT SILT FENCES IN AREAS OF CLEARING, GRADING, OR DRAINAGE PRIOR TO STARTING THOSE ACTIVITIES. 2019 STORMWATERMANAGEMENT MANUAL FOR WESTERN WASHINGTON VOLUME II - CHAPTER 3 - PAGE 3723.THE SILT FENCE SHALL HAVE A 2-FEET MIN. AND A 2½-FEET MAX. HEIGHT ABOVE THE ORIGINAL GROUND SURFACE.4.THE GEOTEXTILE FABRIC SHALL BE SEWN TOGETHER AT THE POINT OF MANUFACTURE TO FORM FABRIC LENGTHS AS REQUIRED. LOCATE ALL SEWNSEAMS AT SUPPORT POSTS. ALTERNATIVELY, TWO SECTIONS OF SILT FENCE CAN BE OVERLAPPED, PROVIDED THAT THE OVERLAP IS LONG ENOUGHAND THAT THE ADJACENT SILT FENCE SECTIONS ARE CLOSE ENOUGH TOGETHER TO PREVENT SILT LADEN WATER FROM ESCAPING THROUGH THEFENCE AT THE OVERLAP.5.ATTACH THE GEOTEXTILE FABRIC ON THE UP-SLOPE SIDE OF THE POSTS AND SECURE WITH STAPLES, WIRE, OR IN ACCORDANCE WITH THEMANUFACTURER'S RECOMMENDATIONS. ATTACH THE GEOTEXTILE FABRIC TO THE POSTS IN A MANNER THAT REDUCES THE POTENTIAL FOR TEARING.6.SUPPORT THE GEOTEXTILE FABRIC WITH WIRE OR PLASTIC MESH, DEPENDENT ON THE PROPERTIES OF THE GEOTEXTILE SELECTED FOR USE. IF WIREOR PLASTIC MESH IS USED, FASTEN THE MESH SECURELY TO THE UP-SLOPE SIDE OF THE POSTS WITH THE GEOTEXTILE FABRIC UP-SLOPE OF THEMESH.7.MESH SUPPORT, IF USED, SHALL CONSIST OF STEEL WIRE WITH A MAXIMUM MESH SPACING OF 2-INCHES, OR A PREFABRICATED POLYMERIC MESH.THE STRENGTH OF THE WIRE OR POLYMERIC MESH SHALL BE EQUIVALENT TO OR GREATER THAN 180 LBS. GRAB TENSILE STRENGTH. THE POLYMERICMESH MUST BE AS RESISTANT TO THE SAME LEVEL OF ULTRAVIOLET RADIATION AS THE GEOTEXTILE FABRIC IT SUPPORTS.8.BURY THE BOTTOM OF THE GEOTEXTILE FABRIC 4-INCHES MIN. BELOW THE GROUND SURFACE. BACKFILL AND TAMP SOIL IN PLACE OVER THE BURIEDPORTION OF THE GEOTEXTILE FABRIC, SO THAT NO FLOW CAN PASS BENEATH THE SILT FENCE AND SCOURING CANNOT OCCUR. WHEN WIRE ORPOLYMERIC BACK-UP SUPPORT MESH IS USED, THE WIRE OR POLYMERIC MESH SHALL EXTEND INTO THE GROUND 3-INCHES MIN.9.DRIVE OR PLACE THE SILT FENCE POSTS INTO THE GROUND 18-INCHES MIN. A 12–INCH MIN. DEPTH IS ALLOWED IF TOPSOIL OR OTHER SOFTSUBGRADE SOIL IS NOT PRESENT AND 18-INCHES CANNOT BE REACHED. INCREASE FENCE POST MIN. DEPTHS BY 6 INCHES IF THE FENCE IS LOCATEDON SLOPES OF 3H:1V OR STEEPER AND THE SLOPE IS PERPENDICULAR TO THE FENCE. IF REQUIRED POST DEPTHS CANNOT BE OBTAINED, THE POSTSSHALL BE ADEQUATELY SECURED BY BRACING OR GUYING TO PRE-VENT OVERTURNING OF THE FENCE DUE TO SEDIMENT LOADING.10.USE WOOD, STEEL OR EQUIVALENT POSTS. THE SPACING OF THE SUPPORT POSTS SHALL BE A MAX-IMUM OF 6-FEET. POSTS SHALL CONSIST OFEITHER:·WOOD WITH MINIMUM DIMENSIONS OF 2 INCHES BY 2 INCHES BY 3 FEET. WOOD SHALL BE FREE OF DEFECTS SUCH AS KNOTS, SPLITS, OR GOUGES.·NO. 6 STEEL REBAR OR LARGER.·ASTM A 120 STEEL PIPE WITH A MINIMUM DIAMETER OF 1-INCH.·U, T, L, OR C SHAPE STEEL POSTS WITH A MINIMUM WEIGHT OF 1.35 LBS./FT.·OTHER STEEL POSTS HAVING EQUIVALENT STRENGTH AND BENDING RESISTANCE TO THE POST SIZES LISTED ABOVE.11.LOCATE SILT FENCES ON CONTOUR AS MUCH AS POSSIBLE, EXCEPT AT THE ENDS OF THE FENCE, 2019 STORMWATER MANAGEMENT MANUAL FORWESTERN WASHINGTON VOLUME II - CHAPTER 3 - PAGE 373 WHERE THE FENCE SHALL BE TURNED UPHILL SUCH THAT THE SILT FENCE CAPTURES THERUNOFF WATER AND PREVENTS WATER FROM FLOWING AROUND THE END OF THE FENCE.12.IF THE FENCE MUST CROSS CONTOURS, WITH THE EXCEPTION OF THE ENDS OF THE FENCE, PLACE CHECK DAMS PERPENDICULAR TO THE BACK OFTHE FENCE TO MINIMIZE CONCENTRATED FLOW AND EROSION. THE SLOPE OF THE FENCE LINE WHERE CONTOURS MUST BE CROSSED SHALL NOT BESTEEPER THAN 3H:1V.·CHECK DAMS SHALL BE APPROXIMATELY 1-FOOT DEEP AT THE BACK OF THE FENCE. CHECK DAMS SHALL BE CONTINUED PERPENDICULAR TO THEFENCE AT THE SAME ELEVATION UNTIL THE TOP OF THE CHECK DAM INTERCEPTS THE GROUND SURFACE BEHIND THE FENCE.·CHECK DAMS SHALL CONSIST OF CRUSHED SURFACING BASE COURSE, GRAVEL BACKFILL FOR WALLS, OR SHOULDER BALLAST. CHECK DAMS SHALLBE LOCATED EVERY 10 FEET ALONG THE FENCE WHERE THE FENCE MUST CROSS CONTOURS.STANDARD NOTES FOR SILT FENCEBMP C235 - STRAW WATTLES2C3BMP C233 - SILT FENCE3C3N.T.S.BMP C105 - STABILIZED CONSTRUCTION ACCESS1N.T.S.C3INTERCEPTOR DIKESINTERCEPTOR DIKES SHALL MEET THE FOLLOWING CRITERIA:·TOP WIDTH: 2 FEET MINIMUM.·HEIGHT: 1.5 FEET MINIMUM ON BERM.·SIDE SLOPE: 2H:1V OR FLATTER.·GRADE: DEPENDS ON TOPOGRAPHY, HOWEVER, DIKE SYSTEM MINIMUM IS 0.5%, AND MAXIMUM IS 1%.·COMPACTION: MINIMUM OF 90 PERCENT ASTM D698 STANDARD PROCTOR.·STABILIZATION: DEPENDS ON VELOCITY AND REACH. INSPECT REGULARLY TO ENSURE STABILITY.·GROUND SLOPES <5%: SEED AND MULCH APPLIED WITHIN 5 DAYS OF DIKE CONSTRUCTION (SEE BMP C121: MULCHING).·GROUND SLOPES 5 - 40%: DEPENDENT ON RUNOFF VELOCITIES AND DIKE MATERIALS. STABILIZATION SHOULD BE DONE IMMEDIATELY USING EITHERSOD OR RIPRAP, OR OTHER MEASURES TO AVOID EROSION.·THE UPSLOPE SIDE OF THE DIKE SHALL PROVIDE POSITIVE DRAINAGE TO THE DIKE OUTLET. NO EROSION SHALL OCCUR AT THE OUTLET. PROVIDEENERGY DISSIPATION MEASURES AS NECESSARY. SEDIMENT-LADEN RUNOFF MUST BE RELEASED THROUGH A SEDIMENT TRAPPING FACILITY.·MINIMIZE CONSTRUCTION TRAFFIC OVER TEMPORARY DIKES. USE TEMPORARY CROSS CULVERTS FOR CHANNEL CROSSING.·SEE TABLE II-3.8: HORIZONTAL SPACING OF INTERCEPTOR DIKES ALONG GROUND SLOPE FOR RECOMMENDED HORIZONTAL SPACING BETWEEN DIKES.BMP C200 INTERCEPTOR DIKE AND SWALE NOTESN.T.S.BMP C207 - ROCK CHECK DAMS4C3N.T.S.INTERCEPTOR SWALESINTERCEPTOR SWALES SHALL MEET THE FOLLOWING CRITERIA:·BOTTOM WIDTH: 2 FEET MINIMUM; THE CROSS-SECTION BOTTOM SHALL BE LEVEL.·DEPTH: 1-FOOT MINIMUM.·SIDE SLOPE: 2H:1V OR FLATTER.·GRADE: MAXIMUM 5 PERCENT, WITH POSITIVE DRAINAGE TO A SUITABLE OUTLET (SUCH AS BMP C241: SEDIMENT POND (TEMPORARY)).·STABILIZATION: SEED AS PER BMP C120: TEMPORARY AND PERMANENT SEEDING, OR BMP C202: RIPRAP CHANNEL LINING, 12 INCHES THICK RIPRAPPRESSED INTO THE BANK AND EXTENDING AT LEAST 8 INCHES VERTICAL FROM THE BOTTOM.ROCK CHECK DAMS NOTES:ROCK SIZE =100% PASSING 8" SQUARE SIEVE40 - 60% PASSING 3" SQUARE SIEVE0 - 10% PASSING .75" SQUARE SIEVEPER VOLUME lll, TABLE 4.5, OPEN CONVEYANCE PROTECTION BIO ENGINEERED LININGALLOWED FOR DESIGN FLOW ≤ 8 FPS. DESIGN FLOWS OF 2.3 TO 3.3 CALCULATED FORTHIS SITE. ENGINEERING BEFORE YOU DIGCALL1-800-424-5555NOT LESS THAN 48 HOURS BEFOREBEGINNING EXCAVATION WHERE ANYUNDERGROUND UTILITIES MAY BE LOCATED.SITE ADDRESS: CSWPPP NOTES & DETAILS (2) 750 - Mc MINN RD PORT TOWNSEND, WA 98368 SOIL AMENDMENT NOTES:CHOOSE 1 OF 3 OPTIONS FOR SOIL AMENDMENT IN ANY AREAS WHERE TOPSOIL REMOVED AND IMPERVIOUS NOT PLACED.ROOT ZONES WHERE TREES ROOTS LIMIT THE DEPTH OF INCORPORATION OF AMENDMENTS ARE EXEMPTED FROM THISREQUIREMENT. PROTECT FENCE AND THESE ROOT ZONES FROM STRIPPING OF SOIL, GRADING, OR COMPACTION TO THEMAXIMUM EXTENT PRACTICAL.SCARIFY SUBSOILS AT LEAST 4 INCHES FOR A FINISHED MAXIMUM DEPTH OF 12 INCHES OF UNCOMPACTED SOIL.INCORPORATE SOME OF THE UPPER MATERIAL TO AVOID STRATIFIED LAYERS WHERE FEASIBLE.ONCE SOIL IS AMENDED, PROTECT FROM COMPACTION AND EROSION.OPTION 1: AMEND SOILS WITH ORGANIC COMPOSTUSE COMPOST AND OTHER MATERIALS THAT MEET THE FOLLOWING ORGANIC CONTENT REQUIREMENTS:- FOR PRE-APPROVED AMENDMENT RATES USE THE COMPOST SPECIFICATION FOR BIORETENTION, WITH THE EXCEPTIONTHAT THE COMPOST MAY HAVE UP TO 35% BIOSOLIDS OR MANURE. THE COMPOST SHALL HAVE ORGANIC MATTER CONTENTOF AT LEAST 40% AND NOT MORE THAN 65%. THE CARBON TO NITROGEN RATIO SHALL BE BELOW 25:1 FOR GENERAL USE ANDNO MORE THAN 35:1 FOR PLANTINGS COMPOSED ENTIRELY OF PLANTS NATIVE TO THE PUGET SOUND LOWLANDS REGION.- CALCULATED AMENDMENT RATES SHALL NOT EXCEED THE CONTAMINANT LIMITS IN TABLE 220-B, TESTING PARAMETERS,WAC 173-350-220. ASSURE THAT THE RESULTING SOIL IS CONDUCIVE TO THE TYPE OF VEGETATION TO BE ESTABLISHED.1.A. LAWN AREA SHALL BE AMMENDED TO 5% ORGANIC CONTENTPLACE 1.75" COMPOST AND TILL TO AN 8" DEPTH. CHECK TO CONFIRM THE FOLLOWING:ACHIEVE AN ORGANIC MATTER CONTENT OF 4% MINIMUM AS MEASURED BY THE LOSS-ON-IGNITION TEST (ASTM D2974 ORTMECC 05.07A.)WATER OR ROLL TO COMPACT OT 85 % MAXIMUM DRY DENSITY, RAKE TO SMOOTH, AND REMOVE SURVADE WOODY DEBRISAND ROCKS LARGER THAN 1 " DIAMETER.1.B. LANDSCAPE AREAS SHALL BE AMMENDED TO 10% ORGANIC CONTENTPLACE 3" COMPOST AND TILL TO AN 8" DEPTH. CHECK TO CONFIRM THE FOLLOWING:- ACHIEVE AN ORGANIC MATTER CONTENT OF 8% MINIMUM AS MEASURED BY THE LOSS-ON-IGNITION TEST (ASTM D2974 ORTMECC 05.07A.)- ACHIEVE A PH FROM 6.0 TO 8.0 OR MATCHING THE PH OR THE ORIGONAL UNDISTURBED SOIL.- ACHIEVE A MINIMUM DEPTH OF 8 INCHES.AFTER PLANTING, MULCH BEDS WITH 2 TO INCHES OF ORANIC MATERIAL SUCH AS ABROBISTS CHIPS, BARK, SHREDDEDLEAVES, COMPOST, ETC. DO NOT USE FINE BARK BECAUSE IT CAN SEAL THE SURFACE.OPTION 2: SOIL STOCKPILINGREMOVE AND STOCKPILE THE DUFF LAYER AND THE ENTIRE DEPTH OF NATIVE TOPSOIL UP TO A MAX OF 3 FEET.TEMPORARILY STABILIZE ON SITE IN A DESIGNATED, CONTROLLED AREA, NOT ADJACENT TO PUBLIC RESOURCES OR CIRITCALAREAS.REAPPLY TO PORTIONS OF THE SITE BROUGHT TO FINAL GRADE. OVER-EXCAVATE CUT SECTIONS IF NECESSARY TO PLACEAT LEAST THE SAME DEPTH OF TOPSOIL THAT WAS ON SITE PRE-DEVELOPMENT, UP TO A MAXIMUM OF 3 FEET.RIP ANY CEMENTED TILL LAYERS TO A DEPTH OF 6 INCHES IN CUT SECTIONS AND MIX STOCKPILED TOPSOIL THOROUGHLYINTO THE RIPPED TILL TO PROVIDE A GRADUAL TRANSITION BETWEEN TILL AND TOPSOIL.PLACE TOPSOIL IN LIFTS NOT GREATER THAN 1 FOOT DEEP AND COMPACT TO A DENSITY THAT MATCHES EXISITNGCONDITIONS.OPTION 3: IMPORTING SOILLAWN AREAS USE A MIX AT LEAST 20 % BY VOLUME COMPOST WITH REMAINING MINERAL SOIL CONTAINING NO MORE THAN 5%PASSING THE US#200 SIEVE.LANDSCAPE AREAS USE A MIX AT LEAST 35% BY VOLUME COMPOST WITHMINERAL SOIL CONTAINING NO MORE THAN 5% PASSING THE US#200 SIEVE.BMP C123 PLASTIC COVERING NOTES:1.PLASTIC SHEETING SHALL HAVE A MINIMUM THICKNESS OF 6 MILS AND SHALL MEET THEREQUIREMENTS OF THE STATE STANDARD SPECIFICATIONS SECTION 9-14.5.2.COVERING SHALL BE INSTALLED AND MAINTAINED TIGHTLY IN PLACE BY USING SANDBAGSOR TIRES ON ROPES WITH A MAXIMUM 10-FOOT GRID SPACING IN ALL DIRECTIONS. ALLSEAMS SHALL BE TAPED OR WEIGHTED DOWN FULL LENGTH AND THERE SHALL BE AT LEASTA 12 INCH OVERLAP OF ALL SEAMS.3.CLEAR PLASTIC COVERING SHALL BE INSTALLED IMMEDIATELY ON AREAS SEEDED BETWEENNOVEMBER 1 AND MARCH 31 AND REMAIN UNTIL VEGETATION IS FIRMLY ESTABLISHED.4.WHEN THE COVERING IS USED ON UN-SEEDED SLOPES, IT SHALL BE KEPT IN PLACE UNTILTHE NEXT SEEDING PERIOD.5.PLASTIC COVERING SHEETS SHALL BE BURIED TWO FEET AT THE TOP OF SLOPES IN ORDERTO PREVENT SURFACE WATER FLOW BENEATH SHEETS.6.PROPER MAINTENANCE INCLUDES REGULAR CHECKS FOR RIPS AND DISLODGED ENDS.7.PLASTIC COVERING MAY BE USED ON DISTURBED AREAS THAT REQUIRE COVER MEASURESFOR LESS THAN 30 DAYS, EXCEPT AS STATED BELOW.8.PLASTIC IS PARTICULARLY USEFUL FOR PROTECTING CUT AND FILL SLOPES ANDSTOCKPILES. NOTE: THE RELATIVELY RAPID BREAKDOWN OF MOST POLYETHYLENESHEETING MAKES IT UNSUITABLE FOR LONG-TERM (GREATER THAN 6 MONTHS)APPLICATIONS.9.DUE TO RAPID RUNOFF CAUSED BY PLASTIC COVERING, DO NOT USE THIS METHODUPSLOPE OF AREAS THAT MIGHT BE ADVERSELY IMPACTED BY CONCENTRATED RUNOFF.SUCH AREAS INCLUDE STEEP AND/OR UNSTABLE SLOPES.10.PLASTIC SHEETING MAY RESULT IN INCREASED RUNOFF VOLUMES AND VELOCITIES,REQUIRING REQUIRING ADDITIONAL ONSITE MEASURES TO COUNTERACT THE INCREASES.CREATING A TROUGH WITH WATTLES OR OTHER MATERIAL CAN CONVEY CLEAN WATERAWAY FROM THESE AREAS.11.WHENEVER PLASTIC IS USED TO PROTECT SLOPES INSTALL WATER COLLECTION MEASURESAT THE BASE OF THE SLOPE. THESE MEASURES INCLUDE PLASTIC-COVERED BERMS,CHANNELS AND PIPES USED TO CONVEY CLEAN RAINWATER AWAY FROM BARE SOIL ANDDISTURBED AREAS. DO NOT MIX CLEAN RUNOFF FROM PLASTIC COVERED SLOPE WITHDIRTY RUNOFF FROM A PROJECT.1.STOCKPILES SHALL BE STABILIZED (WITH PLASTIC COVERING OR OTHER APPROVED DEVICE)DAILY BETWEEN NOVEMBER 1 AND MARCH 31.2.IN ANY SEASON, SEDIMENT LEACHING FROM STOCKPILES MUST BE PREVENTED.3.TOPSOIL SHALL NOT BE PLACED WHILE IN FROZEN OR MUDDY CONDITION, WHEN THESUBGRADE IS EXCESSIVELY WET, OR WHEN CONDITIONS EXIST THAT MAY OTHERWISE BEDETRIMENTAL TO PROPER GRADING OR PROPOSED SODDING OR SEEDING.4.PREVIOUSLY ESTABLISHED GRADES ON THE AREAS TO BE TOPSOILED SHALL BE MAINTAINEDACCORDING TO THE APPROVED PLAN.5.SIDE SLOPES OF THE STOCKPILE SHALL NOT EXCEED 2H: 1V .BMP C123 STOCKPILED TOPSOIL NOTES:EROSION CONTROL NOTES:1.THE IMPLEMENTATION OF THESE TESC PLANS AND THE CONSTRUCTION, MAINTENANCE, REPLACEMENT, AND UPGRADING OFTESC FACILITIES IS THE RESPONSIBILITY OF THE APPLICANT/ CONTRACTOR UNTIL ALL CONSTRUCTION IS COMPLETED ANDAPPROVED, VEGETATION/LANDSCAPING IS ESTABLISHED AND THE ENTIRE SITE IS STABILIZED.2.THE BOUNDARIES OF THE CLEARING LIMITS SHOWN ON THIS PLAN SHALL BE CLEARLY MARKED IN THE FIELD PRIOR TOCONSTRUCTION. DURING THE CONSTRUCTION PERIOD, NO DISTURBANCE BEYOND THE CLEARING LIMITS SHALL BE PERMITTED.THE MARKING SHALL BE MAINTAINED BY THE APPLICANT/ CONTRACTOR FOR THE DURATION OF CONSTRUCTION.3.THE TESC FACILITIES SHOWN ON THIS PLAN SHALL BE CONSTRUCTED PRIOR TO AND/OR IN CONJUNCTION WITH ALL CLEARINGAND GRADING ACTIVITIES, AND IN SUCH A MANNER AS TO ENSURE THAT SEDIMENT AND SEDIMENT LADEN WATER DO NOT ENTERTHE DRAINAGE SYSTEM OR ROADWAYS, OR VIOLATE APPLICABLE WATER STANDARDS.4.THE TESC FACILITIES SHOWN ON THIS PLAN ARE THE MINIMUM REQUIREMENTS FOR ANTICIPATED SITE CONDITIONS. DURINGTHE CONSTRUCTION PERIOD, TESC FACILITIES SHALL BE UPGRADED AS NEEDED FOR UNEXPECTED STORM EVENTS AND TOENSURE THAT SEDIMENT AND SEDIMENT-LADEN WATER DO NOT LEAVE THE SITE.5.THE CESCL, CPESC, OR ESC LEAD SHALL BE IDENTIFIED IN THE SWPPP AND SHALL BE ONSITE OR ON-CALL AT ALL TIMES.6.THE CESCL, CPESC, OR ESC LEAD MUST BE KNOWLEDGEABLE IN THE PRINCIPLES AND PRACTICES OF EROSION AND SEDIMENTCONTROL AND HAVE THE SKILLS TO ASSESS:a. SITE CONDITIONS AND CONSTRUCTION ACTIVITIES THAT COULD IMPACT THE QUALITY OF STORMWATER.b. EFFECTIVENESS OF EROSION AND SEDIMENT CONTROL MEASURES USED TO CONTROL THE QUALITY OF STORMWATER DISCHARGES.7.THE CESCL, CPESC, OR ESC LEAD MUST EXAMINE STORMWATER VISUALLY FOR THE PRESENCE OF SUSPENDED SEDIMENT,TURBIDITY, DISCOLORATION, AND OIL SHEEN AND EVALUATE THE EFFECTIVENESS OF BMPS TO DETERMINE IF IT IS NECESSARYTO INSTALL, MAINTAIN, OR REPAIR BMPS.8.THE CESCL, CPESC, OR ESC LEAD MUST INSPECT ALL AREAS DISTURBED BY CONSTRUCTION ACTIVITIES, ALL BMPS, AND ALLSTORMWATER DISCHARGE POINTS AT LEAST ONCE EVERY CALENDAR WEEK AND WITHIN 24 HOURS OF ANY DISCHARGE FROMTHE SITE. (INDIVIDUAL DISCHARGE EVENTS THAT LAST MORE THAN ONE DAY DO NOT REQUIRE DAILY INSPECTIONS). THE CESCLOR INSPECTOR MAY REDUCE THE INSPECTION FREQUENCY FOR TEMPORARY STABILIZED, INACTIVE SITES TO ONCE EVERYCALENDAR MONTH.9.CONSTRUCTION SITE OPERATORS MUST CORRECT ANY PROBLEMS IDENTIFIED BY THE CESCL, CPESC, OR ESC LEAD BY:a. REVIEWING THE SWPPP FOR COMPLIANCE WITH THE 13 CONSTRUCTION SWPPP ELEMENTS AND MAKING APPROPRIATE REVISIONS WITHIN 7 DAYS OF THE INSPECTION.b. FULLY IMPLEMENT AND MAINTAIN APPROPRIATE SOURCE CONTROL AND/OR TREATMENT BMPS AS SOON AS POSSIBLE BUT CORRECTING THE PROBLEM WITHIN 10 DAYS.c, DOCUMENTING BMP IMPLEMENTATION AND MAINTENANCE IN THE SITE LOG BOOK. (REQUIRED FOR SITES LARGER THAN 1 ACRE BUT RECOMMENDED FOR ALL SITES).SAMPLING AND ANALYSIS OF THE STORMWATER DISCHARGES FROM A CONSTRUCTION SITE MAY BE NECESSARY ON ACASE-BY-CASE BASIS TO ENSURE COMPLIANCE WITH STANDARDS. ECOLOGY OR THE CITY WILL ESTABLISH THESE MONITORINGAND ASSOCIATED REPORTING REQUIREMENTS.10.AT NO TIME SHALL MORE THAN ONE FOOT OF SEDIMENT BE ALLOWED TO ACCUMULATE WITHIN A CATCH BASIN SEDIMENT TRAP.11.ALL CATCH BASINS AND CONVEYANCE LINES SHALL BE CLEANED PRIOR TO PAVING. THE CLEANING OPERATION SHALL NOTFLUSH SEDIMENT-LADEN WATER INTO THE DOWNSTREAM SYSTEM.12.STABILIZED CONSTRUCTION ENTRANCES SHALL BE INSTALLED AT THE BEGINNING OF CONSTRUCTION AND MAINTAINED FOR THEDURATION OF THE PROJECT. ADDITIONAL MEASURES MAY BE REQUIRED TO ENSURE THAT ALL PAVED AREAS ARE KEPT CLEANFOR THE DURATION OF THE PROJECT.BMP C120 PERMANENT STABILIZATION PLAN1.AMEND DISTURBED SOILS NOT UNDER CONSTRUCTED SURFACES PER NOTES. INSTALL SURFACE WATER RUN-OFF CONTROLFEATURES.a.PLANT WITH MEADOW MIX - FILTER STRIP. UPPER SWALE MIX AT 120 LBS/ACRE60% MIN. DWARF TALL FESCUEFESTUCA SPP. (EG. SILVERDALE, MARY MUSTANG)REMAINDER:RED FESCUE (FESCTUCA RUBRA)BLUE OATGRASS (HELICTOTRICHON SEMPERVIRENS)BUFFALO GRASS (BUCHLOE DACTYLAIDES)TUFTED FESCUE (FESCTUCA AMETHYSTINE)WHITE LAWN CLOVER (TRIFOLIUM REPENS)3.SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 15 REQUIRE IRRIGATION.4.SEED BEDS PLANTED BETWEEN OCTOBER 15 AND APRIL 30 MAY REQUIRE COVERING OR SURFACE ARMORING MAY BE REQUIREDTO PROTECT THE SEEDLING STRUCTURES. INSTALL 4'x4'x40 LF INFILTRATION TRENCHRIM=132.78 (ME)IE(E) 6" PVC=127.44IE(W) 6" PVC PERF @ 0.0%=127.44IE(W) 6" PVC=127.44GARAGE700 SQ FTFF=136.5DS3PROPERTY LINE(TYP.)PROPERTYLINEPRIMARY DRAINFIELDDESIGN BY OTHERSRESERVE DRAINFIELDDESIGN BY OTHERSRESERVE DRAINFIELD DESIGN BYOTHERS50' MIN.11'PROPOSED WELLDESIGN BY OTHERS1 0 'PROPOSED PRIVATEWATER ESMT.PROPOSEDPRIVATE WATERSS 6" PVCIE: 132.00 (MIN.)SS 6" PVC IE: 130.50 (MAX.)SS 6" PVCIE: 130.50 (MAX.)PROPERTY LINE(TYP.)100' WELLPROTECTIONRADIUSPROPOSEDDRAINAGE SWALEDS1DS4DS5DS7DS2DS8DS9DS6GRADE BREAK2 0 'R17'7'SS 6" PVCIE: 132.00 (MIN.)R20'138138136134 134136132136134ME:133.94ME:136.35ME:136.82ME:133.48ME:133.96ME:134.05ME:136.05ME:137.90ME:137.03ME:138.34ME:138.88ME:138.97ME:138.91ME:138.93ME:133.41R21.5'ME:132.83ME:133.00FG:134.00ME:134.00ME:137.59ME:136.75PROPOSED 20' FIRE ACCESS PER INTERNATIONAL FIRE CODEW/ 150 LF FIRE HOSE LENGTH ACCESS TO ALL SIDES OF BUILDINGME:132.28ME:133.00ME:138.69ME:138.93FG:132.80ME:132.69ME:131.80ME:131.70ME:131.74FG:136.72FG:136.90FG:137.00FG:137.46FG:132.96FG:136.45FG:136.95FG:136.22FG:137.39FG:138.79FG:138.79FG:137.52FG:137.00FG:137.79FG:135.35LP:132.32FG:137.81FG:136.9713.7'15'13.2'18.5'FG:137.46FG:137.00GRADE BREAKGRADE BREAKGRADE BREAKFG:136.08FG:136.05FG:135.93FG:136.52LP:132.94LP:135.64HOUSE3324 SQ FTFF=137.5FG:136.46FG:137.46FG:137.46FG:137.46FG:137.00FG:136.3210'SITE BENCHMARKTOP OF REBAR & CAPN: 5027.0659'E: 4980.1555'EL.= 137.73SETBACK LINES(TYPICAL)5'5'20' ESMT.SETBACK5'YD #1YD #2CB #1YD #3TIGHTLINE DOWNSPOUTSW/6" PVC @ 0.5% (MIN) TOSUMP STRUCTURE TOINFILTRATION TRENCHC651 0 'TIGHTLINE DOWNSPOUTSW/6" PVC @ 0.5% (MIN) TOSUMP STRUCTURE TOINFILTRATION TRENCHC6523LF 6" PVC @ 1.0%C66C68PROPOSEDDRAINAGE SWALEC68TOP DRESS AND RESTOREEXISTING GRAVEL ROADC68 ENGINEERING BEFORE YOU DIGCALL1-800-424-5555NOT LESS THAN 48 HOURS BEFOREBEGINNING EXCAVATION WHERE ANYUNDERGROUND UTILITIES MAY BE LOCATED.SITE ADDRESS: GRADING & STORM DRAINAGE PLAN 750 - Mc MINN RD PORT TOWNSEND, WA 983681.SLOPE EXTERIOR GRADES AWAY FROM STRUCTURES AT 2% MIN FOR 5 FT OR MORE TOACHIEVE SURFACE DRAINAGE.2.PROVIDE FOUNDATION DRAINS OF RIGID, PERFORATED PVC SURROUNDED IN WASHEDPEA GRAVEL. CONSTRUCT DRAINS TO ACHIEVE GRAVITY DISCHARGE AT LEAST 5 FTFROM FOUNDATIONS. DO NOT CONNECT ROOF DRAINAGE TO FOUNDATION DRAINS,RUN SEPARATELY TO BASIN OR OUTFALL.FOUNDATION GRADING AND DRAINAGE NOTESEG = EXISTING GRADEFG = FINISHED GRADEME = MATCH EXISTING GRADELP = LOW POINT (FINISHED GRADE)DS = DOWNSPOUTIE = INVERT ELEVATIONTYP = TYPICALABBREVIATIONS020101" = 20'40NAVD 88 (PER JC GIS)CONTOUR INTERVAL = 2'THE BASIS OF BEARING IS N88°29'21"W FROM IRON PIPE AT S.E. CORNER SEC. 1 AND REBAR &CAP SET BY EE ANDERSON PER PRELIMINARY ALTA SURVEY PERFORMED BY INFORMED LANDSURVEY AND TOPOGRAPHIC SURVEY PERFORMED BY JOHNSTON LAND SURVEYINGBASIS OF BEARINGSVERTICAL DATUMSTRUCTURESTRUCTURE TABLEDETAILSNORTHING & EASTINGYD #1 (BEEHIVE GRATE)RIM=133.39IE(OUT) 6" PVC=130.89N: 5067.7984'E: 4966.0026'YD #2 (SOLID LID)W/ DOWNTURN ELBOWRIM=133.39IE(IN) 6" PVC=130.13IE(OUT) 6" ELBOW=129.35N: 5032.4687'E: 4831.7224'YD #3 (BEEHIVE GRATE)RIM=132.32IE(OUT) 6" PVC=127.44N: 5010.1374'E: 4763.5791'CB #1 (SOLID LID)RIM=132.59IE(IN) 6" PVC=129.12IE(OUT) 6" PVC=127.44N: 5036.1374'E: 4808.6124' ENGINEERING BEFORE YOU DIGCALL1-800-424-5555NOT LESS THAN 48 HOURS BEFOREBEGINNING EXCAVATION WHERE ANYUNDERGROUND UTILITIES MAY BE LOCATED.SITE ADDRESS: GRADING & STORM DRAINAGE NOTES & DETAILS 750 - Mc MINN RD PORT TOWNSEND, WA 98368BUILDINGROOF DOWNSPOUTSERVES UP TO700 S.F. OF ROOFNOTES:1.TIGHTLINE ROOF DOWNSPOUTS TOINFILTRATION TRENCH SYSTEMEXISTING VEGETATIONDOWNSPOUT C.O. "Y"(TYPICAL)DOWNSPOUT TIGHTLINE TO SUMP STRUCTURE TOINFILTRATION PER PLANDO NOT CONNECT DOWNSPOUT LINES ANDFOOTING DRAINS6" MIN.DOWNSPOUT DETAILN.T.S.5C6INFILTRATION TRENCH DETAILN.T.S.6C6SUMP W/SOLID LIDDRAINAGE SWALE DETAILN.T.S.8C6SUBGRADE: EXISTING FILL COMPACTED TO 92% MDD OR STRUCTURAL FILLBASE: 6" OF CRUSHED SURFACING BASE COURSESLOPE VARIES20'1.5'SHOULDER2:1SURFACING: 4" CONCRETE JOINTS AND FINISH PER WSDOT AND/OR ARCHITECTURALCONCRETE DRIVEWAY SECTION (TYPICAL)N.T.S.7C62: 1 1.5'SHOULDER2: 1 2:1 ENGINEERING BEFORE YOU DIGCALL1-800-424-5555NOT LESS THAN 48 HOURS BEFOREBEGINNING EXCAVATION WHERE ANYUNDERGROUND UTILITIES MAY BE LOCATED.SITE ADDRESS: GRADING & STORM DRAINAGE NOTES 750 - Mc MINN RD PORT TOWNSEND, WA 98368THE CONTRACTOR SHALL NOTIFY THE ENGINEER IN THE EVENT ORDISCOVERY OF POOR SOILS, GROUNDWATER OR DISCREPANCIES INTHE EXISTING CONDITIONS AS NOTED ON THE PLANS.1.MAXIMUM SLOPE STEEPNESS SHALL BE 2:1 (HORIZONTAL TOVERTICAL) FOR CUT AND FILL SLOPES.2.UNLESS OTHERWISE SPECIFIED, ALL EMBANKMENTS IN THEPLAN SET SHALL BE CONSTRUCTED IN ACCORDANCE WITHSECTION 2-03.3(14)B OF THE WSDOT STANDARDSPECIFICATIONS. EMBANKMENT COMPACTIONS SHALLCONFORM TO SECTION 2-03.3(14)C, METHOD B OF SAIDSTANDARD SPECIFICATIONS.3.EMBANKMENTS DESIGNED TO IMPOUND WATER SHALL BECOMPACTED TO 95% MAXIMUM DENSITY PER SECTION2-03.3(14)C, METHOD C OF WSDOT STANDARD SPECIFICATIONS.4.ALL AREAS RECEIVING FILL MATERIAL SHALL BE PREPARED BYREMOVING VEGETATION, NON-COMPLYING FILL, TOPSOIL ANDOTHER UNSUITABLE MATERIAL, BY SCARIFYING THE SURFACETO PROVIDE A BOND WITH THE NEW FILL, AND WHERE SLOPESARE STEEPER THAN 3 HORIZONTAL TO 1 VERTICAL AND THEHEIGHT IS GREATER THAN 5 FT., BY BENCHING INTO SOUNDCOMPETENT MATERIAL AS DETERMINED BY A SOILS ENGINEER.5. FOR SLOPES STEEPER THAN SET OUT ABOVE, AND ABOVE 4FEET IN HEIGHT, AN ENGINEERED STABILIZATION IS REQUIRED.A GEOSYNTHETIC SOIL WALL PER WSDOT DETAIL 3.09.00 ISPREFERRED.GRADING NOTES:THESE NOTES SUMMARIZE SELECT RECOMMENDATIONS MADE IN THE GEOTECHNICAL REPORT.FOR COMPLETE BACKGROUND INFORMATION, SEE THE REPORT AND FOR FIELD APPROVALSCONSULT THE GEOTECHNICAL ENGINEER.1.REMOVE ALL TOPSOIL, ORGANICS, ROOTS, DEBRIS, LOOSE SOIL AND DELTERIOUSMATERIAL FROM CONSTRUCTION AREAS. STOCKPILE TOPSOIL SEPARATELY FROM OTHERSOILS. ORGANICS MAY BE MULCHED AT CONTRACTORS OPTION.2.RE-USED EXCAVATED TOPSOIL IN LANDSCAPE AREAS ONLY. IF RE-USABLE QUANTITIESARE INSUFFICIENT, SUPPLEMENT WITH COMPOST OR IMPORTED TOPSOIL TO MEETAPPLICABLE SOIL STANDARD.3.COMPLETELY REMOVE LOOSE SOIL FROM UNDER NEW FOUNDATIONS, WALL FOOTINGS,WET UTILITY TRENCH BEDS, AND ANY AREAS SUPPORTING STRUCTURAL LOADS.4.FOUNDATIONS SHALL BEAR ONLY ON UNDISTURBED MEDIUM DENSE NATIVE SOILS OR ONSTRUCTURAL FILL. A 1.5 H: 1 V LINE EXTENDING DOWN FROM ANY FOOTING MUST NOTDAYLIGHT. A 1 H: 1 V LINE MUST NOT INTERSECT ANOTHER FOOTING, NOR INTERSECT ANYFILL COMPACTED TO LESS THAN 95% MODIFIED PROCTOR PER ASTM-1557.5.COMPACT EXPOSED GROUND IN AREAS TO RECEIVE STRUCTURAL FILL TO A FIRM ANDUNYIELDING CONDITION. PROOFROLLING IS RECOMMENED TO BRING THE UPPER 1 FT OFSUBGRADE SOILS TO AT LEAST 95% MAX. DRY DENSITY (M.D.D) PER ASTM D1557. FORHIGH-MOISTURE SILTY SOILS OR OTHER CONDITIONS WHERE COMPACTION ISUNOBTAINABLE OR INADVISABLE, OVER EXCAVATE AND PLACE STRUCTURAL FILL.CONTACT THE GEOTECHNICAL FOR OBSERVATION OF SUBGRADE DURING PROOFROLLING.6.PLACEMENT OF STRUCTURAL FILL: SELECTION, PLACEMENT, AND COMPACTION ISWEATHER DEPENDENT.A.STRUCTURAL FILL IS NON-ORGANIC SOIL ACCEPTABLE TO THE GETOTECHNICAL ENGINEER,WHETHER OBTAINED ONSITE OR IMPORTED, SUCH AS 2014 WSDOT M-41 9-03.14(1) 'GRAVELBORROW' IF CONDITIONS ARE DRY.B.SOILS OF >5% RETAINED ON No. 200 SCREEN ARE CONSIDERED MOISTURE SENSITIVE ANDLIMITED TO DRY WEATHER PLACEMENT AT OPTIMUM +- 2% OF M.D.D.C.FOR WET WEATHER FILLS OR WHEN PROPER COMPACTION CANNOT BE OBTAINED, SELECTFREE-DRAINING GRAVEL AND/OR SAND WITH AT LEAST 25% RETAINED ON THE NO. 4 SIEVEAND 5% MAXIMUM BY WEIGHT ON THE MINUS 200 SIEVE FRACTION, SUCH AS GENERALLYCONFORMS TO 2014 WSDOT 9-03.14(2) 'SELECT BORROW'.D.PLACE STRUCTURAL FILLS IN 10-IN MAX LOOSE LIFTS, COMPACTING EACH LIFT TO 95%MODIFIED PROCTOR PER ASTM-1557, EXCEPT TO 90% WITHIN 2 FT OF UTILITY LINES INTRENCHES. FINER SOILS REQUIRE THINNER LIFTS. CONTACT GEOTECHNICAL FIRM FORFILL TESTING. 72 HOURS ADVANCE NOTICE IS REQUIRED TO PERFROM A LABORATORYPROCTOR TEST TO DETERMINE THE CORRESPONDING FIELD COMPACTION STANDARD.7.OVERBUILD FILL SLOPES AND TRIM BACK TO FINAL GRADE OR SURFACE COMPACT TOADEQUATE DENSITY.8.PERMANENT CUT SLOPES IN MEDIUM DENSE NATIVE SOILS OR STRUCTURAL FILLS SHALLNOT EXCEED 2 H: 1 V INCLINATIONS.9.FROZEN SUBGRADES SHALL BE RECOMPACTED AFTER THAWING AND BEFORE PLACINGSUBSEQUENT LIFTS.STRUCTURAL FILL NOTES:1. ALL WORKMANSHIP AND MATERIALS SHALL BE IN ACCORDANCE WITH COUNTYSTANDARDS AND THE MOST CURRENT COPY OF THE STATE OF WASHINGTONSTANDARD SPECIFICATIONS FOR, ROAD, BRIDGE AND MUNICIPAL CONSTRUCTION(WSDOT/APWA) AND AS AMENDED BY THE COUNTY OR THE STATE.2. TEMPORARY EROSION/WATER POLLUTION PREVENTION MEASURES SHALL BEREQUIRED IN ACCORDANCE WITH THE PIERCE COUNTY STORMWATER MANAGEMENTMANUAL AND THE DEPT. OF ECOLOGY'S CONSTRUCTION STORMWATER GENERALPERMIT. SHOULD THE TEMPORARY EROSION AND SEDIMENTATION CONTROL MEASURES ASSHOWN ON THIS DRAWING NOT PROVE ADEQUATE TO CONTROL EROSION ANDSEDIMENTATON, THE APPLICANT/CONTRACTOR SHALL INSTALL ADDITIONALFACILITIES AS NECESSARY TO PROTECT ADJACENT PROPERTIES, SENSITIVE AREAS,NATURAL WATER COURSES, AND/OR STORM DRAINAGE SYSTEMS.3. CALL THE UNDERGROUND LOCATE LINE 1-800-424-5555 A MINIMUM OF 48 HOURSPRIOR TO ANY EXCAVATIONS.4. THE STORM DRAINAGE SYSTEM SHALL BE CONSTRUCTED ACCORDING TOAPPROVED PLANS ON FILE WITH THE COUNTY. ANY SIGNIFICANT DEVIATION FROMTHE APPROVED PLANS WILL REQUIRE WRITTEN APPROVAL FROM THE COUNTY.5. A COPY OF THE APPROVED CONSTRUCTION STORMWATER POLLUTION PREVENTIONPLAN AND STORMWATER PLANS MUST BE ON THE JOB SITE WHENEVERCONSTRUCTION IS IN PROGRESS.6. ALL EROSION CONTROL AND STORMWATER FACILITIES SHALL BE REGULARLYINSPECTED AND MAINTAINED BY THE DESIGNATED CERTIFIED EROSION AND SEDIMENTCONTROL LEAD (CESCL) DURING CONSTRUCTION.7. IT SHALL BE THE SOLE RESPONSIBILITY OF THE CONTRACTOR TO OBTAIN STREETUSE AND OTHER RELATED OR REQUIRED PERMITS PRIOR TO ANY CONSTRUCTIONACTIVITY IN THE MUNICIPALITY'S RIGHT-OF-WAY. IT SHALL ALSO BE THERESPONSIBILITY OF THE CONTRACTOR TO OBTAIN ALL REQUIRED PERMITS PRIOR TOANY CONSTRUCTION. THE CONTRACTOR SHALL ABIDE BY ALL REQUIREMENTS FORTRAFFIC CONTROL & SAFETY WHEN WORKING IN THE ROAD RIGHT-OF-WAY.8. THE CONTRACTOR SHALL NOTIFY THE PROJECT ENGINEER IN THE EVENT ORDISCOVERY OF POOR SOILS, STANDING GROUNDWATER, OR SEVERE DISCREPANCIESFROM SOIL LOG DESCRIPTIONS AS NOTED ON THE PLANS.9. FOR PUBLIC SYSTEMS, THE CONTRACTOR SHALL CALL FOR INSPECTION 48 HOURSPRIOR TO COVERING ANY DRAINAGE STRUCTURE.10. ALL DRAINAGE STRUCTURES, SUCH AS CATCH BASINS AND MANHOLES, NOTLOCATED WITHIN A TRAVELED ROADWAY OR SIDEWALK, SHALL HAVE SOLID LOCKINGLIDS. ALL DRAINAGE STRUCTURES ASSOCIATED WITH A PERMANENTRETENTION/DETENTION FACILITY SHALL HAVE SOLID LOCKING LIDS.STANDARD STORMWATER NOTES:FILL SPECIFICATIONTHE LOCATIONS OF EXISTING UNDERGROUND UTILITIES AREAPPROXIMATE ONLY AND HAVE NOT BEEN INDEPENDENTLY VERIFIED BYTHE OWNER OR ITS REPRESENTATIVE. THE CONTRACTOR SHALLDETERMINE THE EXACT LOCATION OF ALL EXISTING UTILITIES BEFORECOMMENCING WORK AND AGREES TO BE FULLY RESPONSIBLE FOR ANYAND ALL DAMAGES THAT HAPPEN DUE TO THE CONTRACTOR'S FAILURETO LOCATE EXACTLY AND PRESERVE ANY AND ALL UNDERGROUNDUTILITIES. VADER ENGINEERING ASSUMES NO LIABILITY FOR THELOCATION OF UNDERGROUND UTILITIES.UTILITY NOTE:TRENCH NOTE:IF WORKERS ENTER ANY TRENCH OR OTHER EXCAVATION FOUR ORMORE FEET IN DEPTH THAT DOES NOT MEET THE OPEN PITREQUIREMENTS OF WSDOT SECTION 2-09.3(3)B, IT SHALL BE SHOREDAND CRIBBED. THE CONTRACTOR ALONE SHALL BE RESPONSIBLE FORWORKERS SAFETY AND VADER ENGINEERING ASSUMES NORESPONSIBILITY. ALL TRENCH SAFETY SYSTEMS SHALL MEET THEREQUIREMENTS OF THE WASHINGTON INDUSTRIAL SAFETY AND HEALTHACT, CHAPTER 49.17 RCW.FILL MATERIAL SHALL NOT CONTAIN PETROLEUM PRODUCTS, ORSUBSTANCES WHICH ARE HAZARDOUS, DANGEROUS, TOXIC, OR WHICHOTHERWISE VIOLATE ANY STATE, FEDERAL. OR LOCAL LAW, ORDINANCE,CODE, REGULATION, RULE, ORDER, OR STANDARD.1.ALL WORKMANSHIP AND MATERIALS SHALL CONFORM TO THE MOSTCURRENT STANDARD SPECIFICATIONS FOR ROAD, BRIDGE ANDMUNICIPAL CONSTRUCTION PREPARED BY WSDOT AND APWA ASADOPTED BY THE PIERCE COUNTY DEPARTMENT OF PUBLIC WORKS.2.ANY REVISIONS TO THE ACCEPTED CONSTRUCTION PLANS SHALL BEREVIEWED AND APPROVED BY THE COUNTY PRIOR TO IMPLEMENTATIONIN THE FIELD.3.THE CONTRACTOR SHALL MAINTAIN A SET OF THE ACCEPTEDCONSTRUCTION DRAWINGS ON-SITE AT ALL TIMES WHILE CONSTRUCTIONIS IN PROGRESS.4.IT SHALL BE THE RESPONSIBILITY OF THE CONTRACTOR TO OBTAIN ALLNECESSARY PERMITS FROM THE CITY PRIOR TO COMMENCING ANYWORK WITHIN THE RIGHT-OF-WAY.5.THE CONTRACTOR SHALL BE RESPONSIBLE FOR PROVIDING ADEQUATETRAFFIC CONTROL AT ALL TIMES DURING CONSTRUCTION ALONGSIDE ORWITHIN ALL PUBLIC ROADWAYS. TRAFFIC FLOW ON EXISTING PUBLICROADWAYS SHALL BE MAINTAINED AT ALL TIMES, UNLESS PERMISSION ISOBTAINED FOR ROAD CLOSURE AND/OR DETOURS.6.THE LOCATION OF EXISTING UTILITIES ON THIS PLAN IS APPROXIMATEONLY. THE CONTRACTOR SHALL CONTRACT THE "UNDERGROUNDLOCATE" CENTER AT 811, AND NON-SUBSCRIBING INDIVIDUAL UTILITYCOMPANIES 48 HOURS IN ADVANCE OF THE COMMENCEMENT OF ANYCONSTRUCTION ACTIVITY. THE CONTRACTOR SHALL PROVIDE FORPROTECTION OF EXISTING UTILITIES FROM DAMAGE CAUSED BY THECONTRACTOR'S OPERATIONS.7.ROCKERIES OR OTHER RETAINING FACILITIES EXCEEDING 4 FT. IN HEIGHTREQUIRE A SEPARATE PERMIT.GENERAL NOTES 2045 Ramage | 25 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Appendix B Minimum Requirement #2: Construction Stormwater Pollution Prevention Plan (CSWPPP) Introduction to Construction Storm Water Pollution Prevention Plans This narrative contains the concise, site-specific information about existing conditions constructions schedule, and other pertinent items to supplement what is shown on the drawings. This report shall be located on the construction site or within reasonable access to the site, and the drawings shall be kept on the construction site at all times. One primary purpose of the CSWPPP narrative is to describe the scope of self-conducted inspections and set out inspection frequency. This narrative provides a basic template to document the major observations related to implementing the CSWPPP and actions taken to maintain, repair or improve erosions and sedimentation control as a result of the ongoing inspections. The site and project descriptions are above in the main body of the text. Approval of this Construction SWPPP does not constitute an approval of permanent road or drainage design (e.g., size and location of roads, pipes, restrictors, channels, retention, detention/infiltration facilities, utilities, etc.). These are covered under different narratives and plans. Each site, and some sub-sites, will select which Best Management Practices are expected to protect the receiving waters. For construction sites that eventually discharge to surface water, the primary concern is compliance with Washington State water quality standards. For sites that infiltrate runoff, both the infiltrative capacity of the constructed facilities and the prevention of groundwater pollution will be monitored. The implementation of this Construction SWPPP and the construction, maintenance, replacement, and upgrading of these Construction SWPPP facilities is the responsibility of the applicant/contractor until all construction is completed and approved and vegetation/landscaping is established. There are 13 elements to a Construction Storm Water Pollution Prevention Plan. However, some elements do not apply to every site. When this is encountered, a justification is provided in the text. Note to Reader: The CSWPPP is formatted by section, with typical guidance presented at the beginning of a section and project- specific notes added in bold italic text at the end of the section as applicable. Stirke-thorugh text is used to indicate measures not applicable to this project. 2045 Ramage | 26 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com CESCL REQUIREMENT – Not Triggered A Certified Erosion and Sediment Control Specialist shall be identified in the Construction SWPPP and shall be onsite or oncall at all times for sites that disturb more than 1 acre of soil. Certification may be obtained by an approved training program that meets the erosion and sediment control training criteria established by Ecology. If a preconstruction meeting is held, this person shall attend. See attached BMPC160 Certified Erosion and Sediment Control Lead (CESCL) CESCL___________________________________ 24hr Contact number:______________________ Fax number:______________________________ Address:_________________________________ For this project, with a small disturbed area, an Erosion Control Lead may be named by the Contractor. Keep the contact information up to date if the role is assigned to another. If a pre-construction meeting is held, this person shall attend. ELEMENT 1: MARK CLEARING LIMITS ۰ Prior to beginning land disturbing activities, including clearing and grading, all clearing limits, sensitive areas and their buffers, and trees that are to be preserved within the construction area should be clearly marked, both in the field and on the plans, to prevent damage and offsite impacts. ۰ Plastic, metal, or stake wire fence may be used to mark the clearing limits. ۰ The duff layer, native topsoil, and natural vegetation shall be retained in an undisturbed state to the maximum extent practicable. ELEMENT 2: ESTABLISH CONSTRUCTION ACCESS ۰ Construction vehicle access and exit shall be limited to one route if possible. ۰ Access points shall be stabilized with quarry spall or crushed rock to minimize the tracking of sediment onto public roads. ۰ Wheel wash or tire baths should be located onsite, if applicable. ۰ Roads shall be cleaned thoroughly as needed to protect stormwater infrastructure and downstream water resources. Sediment shall be removed from roads by shoveling or pickup sweeping and shall be transported to a controlled sediment disposal area. Street washing will be allowed only after sediment is removed in this manner. ۰ Street wash wastewater shall be controlled by pumping back onsite, or otherwise 2045 Ramage | 27 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com be prevented from discharging untreated into systems tributary to state surface waters. ۰ Construction access restoration shall be equal to or better than the pre- construction condition. The proposed construction access will be from McMinn Road. ELEMENT 3: CONTROL FLOW RATES ۰ Properties and waterways downstream from development sites shall be protected from erosion due to increases in the volume, velocity, and peak flow rate of stormwater runoff from the project site, as required by local plan approval authority. ۰ Downstream analysis is necessary if changes in flows could impair or alter conveyance systems, stream banks, bed sediment or aquatic habitat. ۰ Where necessary to comply with Minimum Requirement #7 (Flow Control), stormwater retention/detention facilities shall be constructed as one of the first steps in grading. Detention facilities shall be functional prior to construction of site improvements (e.g. impervious surfaces). o The local permitting agency may require pond designs that provide additional or different stormwater flow control if necessary to address local conditions or to protect properties and waterways downstream from erosion due to increases in the volume, velocity, and peak flow rate of stormwater runoff from the project site. o If permanent infiltration ponds are used for flow control during construction, these facilities shall be protected from siltation during the construction phase and plans made for restoration after construction. Due to sandy soils, flow rate during construction is unlikely to be significant ELEMENT 4: INSTALL SEDIMENT CONTROLS ۰ Prior to leaving a construction site, or prior to discharge to an infiltration facility, stormwater runoff from disturbed areas shall pass through a sediment pond or other appropriate sediment removal BMP. Runoff from fully stabilized areas may be discharged without a sediment removal BMP, but must meet the flow control performance standard of Element #3, bullet #1. Full stabilization means concrete or asphalt paving; quarry spalls used as ditch lining; or the use of rolled erosion products, a bonded fiber matrix product, or vegetative cover in a manner that will fully prevent soil erosion. The local permitting authority should inspect and approve areas stabilized by means other than pavement or quarry spalls. ۰ Sediment ponds, vegetated buffer strips, sediment barriers or filters, dikes, and other BMP’s intended to trap sediment onsite shall be constructed as one of the first steps in grading. These BMP’s shall be functional before other land 2045 Ramage | 28 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com disturbing activities take place. ۰ Earthen structures such as dams, dikes, and diversions shall be seeded and mulched according to the timing indicated in Element #5. ۰ BMPs intended to trap sediment on site must be located in a manner to avoid interference with the movement of juvenile salmonids attempting to enter off- channel areas or drainages, often during non-storm events, in response to rain event changes in stream elevation or wetted area. The proposed sediment control measures are provided on Sheet C2 – CSWPP Plan. At minimum, the project will be required to have perimeter protection (compost socks, silt fencing, or equivalent), temporary inlet protection, and appropriate cover measures on the south side where soil will be disturbed. The proposed plan is intended as guidance and the Contractor shall be responsible for implementing and maintaining appropriate sediment controls based on changing site conditions. ELEMENT 5: STABILIZE SOILS ۰ Soils shall be stabilized as outlined below, where downstream water resources or stormwater infrastructure may be negatively affected by sediments (i.e., runoff discharges off the development site). ۰ From October 1 through April 30, no soils shall remain exposed and unworked for more than 2 days. From May 1 to September 30, no soils shall remain exposed and unworked for more than 7 days. This condition applies to all onsite soils, whether at final grade or not. The local permitting authority may adjust these time limits if it can be shown that a development site's erosion or runoff potential justifies a different standard. ۰ Soils shall be stabilized at the end of the shift before a holiday or weekend if needed based on the weather forecast. ۰ Applicable practices include, but are not limited to, compost addition, temporary and permanent seeding, sodding, mulching, plastic covering, soil application of polyacrylamide (PAM), early application of gravel base on areas to be paved, and dust control. ۰ Soil stabilization measures selected should be appropriate for the time of year, site conditions, estimated duration of use, and potential water quality impacts that stabilization agents may have on downstream waters or ground water. ۰ Soil stockpiles must be stabilized from erosion, protected with sediment-trapping measures, and located away from storm drains, waterways, or drainage channels. ۰ Work on linear construction sites and activities, including right-of-way and easement clearing, roadway development, pipelines, and trenching for utilities, shall not exceed the capability of the individual contractor for his portion of the project to install the bedding materials, roadbeds, structures, pipelines, and/or 2045 Ramage | 29 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com utilities, and to re-stabilize the disturbed soils so that: o From October 15 through April 1 no soils shall remain exposed and unworked for more than 2 days and o From April 2 to October 14, no soils shall remain exposed and unworked for more than 7 days. The proposed sediment control details and notes are provided on Sheets C3 and C4 of the Plan set. ELEMENT 6: PROTECT SLOPES ۰ Cut and fill slopes shall be designed and constructed in a manner that will minimize erosion. ۰ Consider soil type and its potential for erosion. ۰ Reduce slope runoff velocities by reducing the continuous length of slope with terracing and diversions, reduce slope steepness, and roughen slope surface. ۰ Offsite stormwater (run-on) shall be diverted away from slopes and disturbed areas with interceptor dikes and swales. Offsite stormwater should be managed separately from stormwater generated on the site. ۰ To prevent erosion, at the top of slopes collect drainage in pipe slope drains or protected channels. Temporary pipe slope drains shall handle the peak flow from a 10-year, 24-hour event; permanent slope drains shall be sized for a 25-year, 24-hour event. Check dams shall be used within channels that are cut down a slope. ۰ Provide drainage to remove ground water intersecting the slope if applicable. The project may include small <3’ landscaping walls to minimize regrading slopes downgrade from the building structures. ELEMENT 7: PROTECT DRAIN INLETS ۰ As needed to protect stormwater infrastructure and downstream water resources, all storm drain inlets made operable during construction shall be protected so that stormwater runoff shall not enter the conveyance system without first being filtered or treated to remove sediment. ۰ All approach roads shall be kept clean, and all sediment and street wash water shall not be allowed to enter storm drains without prior and adequate treatment, unless treatment is provided before the storm drain discharges to waters of the State. ۰ Inlets should be inspected weekly at a minimum and daily during storm events. Inlet protection devices should be cleaned or removed and replaced before six inches of sediment can accumulate. 2045 Ramage | 30 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com New inlets are proposed to collect runoff from pervious and impervious surfaces to maximum runoff flow collection. ELEMENT 8: STABILIZE CHANNELS AND OUTLETS ۰ All temporary onsite conveyance channels shall be designed, constructed and stabilized to prevent erosion from the peak 10-minute flow velocity from a Type 1A 10-year 24-hour frequency storm for the developed condition. ۰ Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes and downstream reaches shall be provided at the outlets of all conveyance systems. ELEMENT 9: CONTROL POLLUTANTS ۰ 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. Woody debris may be chopped and spread on site. ۰ Cover, containment, and protection from vandalism shall be provided for all chemicals, liquid products, petroleum products, and non-inert wastes present on the site (see Chapter 173-304 WAC for the definition of inert waste). Onsite fueling tanks shall include secondary containment. ۰ Maintenance and repair of heavy equipment and vehicles involving oil changes, hydraulic system drain down, solvent and de-greasing cleaning operations, fuel tank drain down and removal, and other activities which may result in discharge or spillage of pollutants to the ground or into stormwater runoff must be conducted using spill prevention measures, such as drip pans. Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Report all spills to 911. Emergency repairs may be performed onsite using temporary plastic placed beneath and, if raining, over the vehicle. ۰ Wheel wash, or tire bath wastewater, shall be discharged to a separate onsite treatment system or to the sanitary sewer if allowed by the local wastewater authority. ۰ Application of agricultural chemicals, including fertilizers and pesticides, shall be conducted in a manner and at application rates that will not result in loss of chemical to stormwater runoff. Manufacturers' label recommendations shall be followed for application rates and procedures. ۰ BMPs shall be used to prevent or treat contamination of stormwater runoff by pH modifying sources. These sources include, but are not limited to, bulk cement, cement kiln dust, fly ash, new concrete washing and curing waters, waste streams generated from concrete grinding and sawing, exposed aggregate processes, and concrete pumping and mixer washout waters. Stormwater discharges shall not cause or contribute to a violation of the water quality standard for pH in the receiving water. 2045 Ramage | 31 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com These activities are not expected during this project, however, the Contractor shall be responsible that no wastes enter the runoff. ELEMENT 10: CONTROL DE-WATERING ۰ All foundation, vault, and trench de-watering water, which has similar characteristics to stormwater runoff at the site, shall be discharged into a controlled conveyance system, prior to discharge to a sediment trap or sediment pond. Channels must be stabilized, as specified in Element #8. ۰ Clean, non-turbid de-watering water, such as well-point ground water, can be discharged to systems tributary to state surface waters, as specified in Element #8, provided the de-watering flow does not cause erosion or flooding of the receiving waters. These clean waters should not be routed through stormwater sediment ponds. ۰ Highly turbid or otherwise contaminated dewatering water, such as from construction equipment operation, clamshell digging, concrete tremie pour, or work inside a cofferdam, shall be handled separately from stormwater at the site. ۰ Other disposal options, depending on site constraints, may include: 1) infiltration, 2) transport offsite in vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not pollute state waters, 3) onsite treatment using chemical treatment or other suitable treatment technologies, or 4) sanitary sewer discharge with local sewer district approval, or 5) use of sedimentation bag with outfall to a ditch or swale for small volumes of localized dewatering. These activities are not expected during this project, however, the Contractor shall be responsible that no wastes enter the runoff. ELEMENT 11: MAINTAIN BMP’S ۰ All temporary and permanent erosion and sediment control BMP’s shall be maintained and repaired as needed to assure continued performance of their intended function. All maintenance and repair shall be conducted in accordance with BMP specifications. ۰ Sediment control BMP’s shall be inspected weekly or after a runoff-producing storm event during the dry season and daily during the wet season. ۰ All temporary erosion and sediment control BMP’s shall be removed within 30 days after final site stabilization is achieved or after the temporary BMP’s are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil areas resulting from removal of BMP’s or vegetation shall be permanently stabilized. ELEMENT 12: MANAGE THE PROJECT ۰ Phasing of Construction Development projects shall be phased where feasible in order to prevent, to the maximum extent practicable, the transport of sediment from the project site during construction. Revegetation of exposed areas and maintenance of that 2045 Ramage | 32 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com vegetation shall be an integral part of the clearing activities for any phase. Clearing and grading activities for developments shall be permitted only if conducted pursuant to an approved site development plan that establishes permitted areas of clearing, grading, cutting, and filling by delineation on the site plans and the development site. ۰ Seasonal Work Limitations Except where approved chemical treatment, full dispersion or infiltration is practiced—clearing, grading, and other soil disturbing activities are prohibited in all watersheds between October 15 and April 1. Based on the information provided, and/or local weather conditions, the local permitting authority may expand or restrict the seasonal limitation on site disturbance. o If, during the course of any construction activity or soil disturbance during the seasonal limitation period, silt-laden runoff leaving the construction site causes a violation of the surface water quality standard; or o If clearing and grading limits or erosion and sediment control measures shown in the approved plan are not maintained. Local governments may restrict clearing and grading activities where site conditions may present a significant risk of impact to property or critical areas. Contact the local government permitting authority for information on specific site restrictions. The following activities are exempt from the seasonal clearing and grading limitations: 1. Routine maintenance and necessary repair of erosion and sediment control BMP’s; 2. Routine maintenance of public facilities or existing utility structures that do not (a) expose the soil or (b) result in the removal of the soil's vegetative cover; and 3. Self-contained project sites, where there is complete infiltration of the water quality design event runoff within the site. ۰ Coordination with Utilities and Other Contractors The primary project proponent shall evaluate, with input from utilities and other contractors, the stormwater management requirements for the entire project, including the utilities, when preparing the Construction SWPPP. ۰ Inspection and Monitoring All BMP’s 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. The person shall have the skills to (1) assess site conditions and construction activities that could impact stormwater runoff quality, and (2) assess erosion and sediment control measure effectiveness. 2045 Ramage | 33 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com A Certified Erosion and Sediment Control Specialist shall be identified in the construction SWPPP and shall be onsite or on-call at all times. Certification may be obtained an approved training program that meets the erosion and sediment control training criteria established by Ecology. If a pre-construction meeting is held, this person shall attend. ۰ Sampling and analysis of the stormwater discharges from a construction site may be necessary on a case-by-case basis to ensure compliance with standards. The local permitting authority may establish monitoring and reporting requirements may be established by the local permitting authority when necessary. The local discharge and surface water standards are: Discharge: Runoff leaving the construction site shall be free of settle able solids, as measured with an Imhoff Cone and in accordance with Standard Methods for the Examination of Water and Wastewater, most recent edition, American Water Works Association. "Free of settle able solids" shall be defined as measuring less than 2.5 mL/L/hr, for storms up to the water quality design event.2 Surface Water: For storms up to the water quality design event, turbidity downstream of a construction site may not increase more than 5 NTU, if upstream turbidity is 50 NTU or less, and may not increase more than 10 percent, if upstream turbidity is over 50 NTU. To the extent practicable, samples should be taken far enough downstream so that the construction site discharge has been well-mixed with the surface water. Whenever inspection and/or monitoring reveals that the BMP’s identified in the Construction SWPPP are inadequate, due to the actual discharge of or potential to discharge a significant amount of any pollutant, appropriate BMP’s or design changes shall be implemented as soon as possible. ۰ Maintaining an Updated Construction SWPPP - The SWPPP shall be retained onsite or within reasonable access to the site. The SWPPP shall be updated within 7 days to reflect any significant changes in the design, construction, operation, or maintenance at the construction site that have, or could have, a significant effect on the discharge of pollutants to waters of the state. The SWPPP shall be updated within 7 days if during inspections or investigations by site staff or local or state officials, it is determined that the SWPPP is ineffective in controlling pollutants such that applicable discharge or surface water standards violations are apparent. ۰ Objective The objective is to control erosion and prevent sediment and other pollutants from leaving the site during the construction phase of a project. 2045 Ramage | 34 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com BMP C160: Certified Erosion and Sediment Control Lead (CESCL) Purpose The project proponent designates at least one person as the responsible representative in charge of erosion and sediment control, and water quality protection. The designated person shall be the Certified Erosion and Sediment Control Lead (CESCL) who is responsible for ensuring compliance with all local, state, and federal erosion and sediment control and water quality requirements. Conditions of Use If a Construction SWPPP or coverage under Ecology’s Construction General Permit is required, a CESCL is required. For single-family residential lots and similarly sized construction projects, the local permitting authority may allow the projects to proceed without a CESCL, or may set lesser certification standards, duties, or responsibilities than those listed below. Design and Installation ۰ The CESCL shall: Specifications ۰Have a current certificate proving attendance in an erosion and sediment control training course that meets the Ecology’s minimum ESC training and certification requirements (see below). A training and certification provider list is available online at http://www.ecy.wa.gov/programs/wq/stormwater/index.html; OR ۰Be a Certified Professional in Erosion and Sediment Control (CPESC) or a Certified Professional in Stormwater Quality (CPSWQ). Training and certification available online at http://www.cpesc.net. ۰ The CESCL shall have authority to act on behalf of the contractor or developer and shall be available, on call, 24 hours per day throughout the period of construction. ۰ The Construction SWPPP shall include the name, 24-hour telephone number, fax number, and address of the designated CESCL. ۰ A CESCL may provide inspection and compliance services for multiple active construction projects. Duties and responsibilities of the CESCL shall include, but are not limited to the following: ۰ Maintaining permit file on site at all times which includes the SWPPP and any associated permits and plans. ۰ Directing BMP installation, inspection, maintenance, modification, and removal. 2045 Ramage | 35 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com ۰ Updating all project drawings and the Construction SWPPP with changes made. ۰ Keeping daily logs, and inspection reports. Inspection reports should include: • Inspection locations, dates and times • Weather information, including conditions during the inspection and recent rainfall events. • A summary list of BMPs implemented, including field observations. The list should include the following: • List of all BMPs on the project site • BMPs inspected • BMPs needing maintenance • BMPs failed and needing replacement • Recommended replacements or other actions • Visual observations or water quality monitoring conducted • Monitoring results • Comments and notes • Facilitate, participate in, and take corrective actions resulting from inspections performed by outside agencies or the owner. 2045 Ramage | 36 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Sample Site Inspection Form From http://www.ecy.wa.gov/programs/wq/stormwater/construction/ Project Name Permit # Inspection Date Time Name of Certified Erosion Sediment Control Lead (CESCL) or qualified inspector if less than one acre Print Name: Approximate rainfall amount since the last inspection (in inches): Approximate rainfall amount in the last 24 hours (in inches): Current Weather Clear Cloudy Mist Rain Wind Fog A. Type of inspection: Weekly Post Storm Event Other B. Phase of Active Construction (check all that apply): Pre Construction/installation of erosion/sediment controls Clearing/Demo/Grading Infrastructure/storm/road s Concrete pours Vertical Construction/buildings Utilities Offsite improvements Site temporary stabilized Final stabilization C. Questions: 1. Were all areas of construction and discharge points inspected? Yes No 2. Did you observe the presence of suspended sediment, turbidity, discoloration, or oil sheen Yes No 3. Was a water quality sample taken during inspection? (refer to permit conditions S4 & S5) Yes No 4. Was there a turbid discharge 250 NTU or greater, or Transparency 6 cm or less?* Yes No 5. If yes to #4 was it reported to Ecology? Yes No 6. Is pH sampling required? pH range required is 6.5 to 8.5. Yes No If answering yes to a discharge, describe the event. Include when, where, and why it happened; what action was taken, and when. 2045 Ramage | 37 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com 2045 Ramage | 38 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com 2045 Ramage | 39 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com 2045 Ramage | 40 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com 2045 Ramage | 41 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com 2045 Ramage | 42 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com 2045 Ramage | 43 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Appendix C Soils Information Soils Reports attached: • Geotechnical Engineering Report by South Sound Geotechnical Consulting • Updated Geotechnical Report by Georesources June 30, 2023 Richard Ramage 7051 Lincoln Parkway SW #E Seattle, Washington 98136 Updated Geotechnical Engineering Report Proposed Single-Family Residence 750 McMinn Road Jefferson Washington PN: 002014003 Doc ID: Ramage.McMinnRoad.RG INTRODUCTION This Updated Geotechnical Engineering Report summarizes our site observations, subsurface explorations, slope stability analysis, assessment of potential geologically hazardous areas at or near the site and provides geotechnical recommendations for a proposed single-family residence to be constructed at the site. The residence will be located at 750 McMinn Road in the Port Townsend area of Jefferson County, Washington. The general location of the site is shown on the attached Site Location Map, Figure 1. South Sound Geotechnical Consulting (SSGC) completed a Geotechnical Engineering Report for this project dated September 8, 2020. This Geotechnical Engineering Report addresses comments from Jefferson County (the County), as the County requested justification of a 75-foot setback from the top of a high-bank shoreline bluff previously recommended in the SSGC report. Our understanding of the project is based on our conversations and email correspondences with members of your design team including Andrew Stephenson, Vader Engineering, and Holli Lynn Jackowski, Hayne Architects; our review of the SSGC report for this project dated September 8, 2020; our review of the Preliminary Grading and Storm Drainage Plan dated May 24, 2023 and the Preliminary Site Plan dated March 14, 2023; our review of the publicly available geologic literature for the project area; our June 19, 2023 site visit and subsurface explorations; our understanding of the Jefferson County Unified Development Code for Critical Areas, and our experience in Jefferson County. The site is currently undeveloped. As shown on the Site & Exploration Plan, Figure 2, a 3,324 square foot single-family residence is proposed in the upper, southeast corner of the parcel with onsite septic and water well, 700 square-foot garage, driveway, and other associated residential utilities. As recommended in the SSGC geotechnical report for this project, the proposed residence and garage will be founded on conventional spread footings. SSGC recommended that the residence be setback 75 feet from the top of the bluff, but there was no stability analysis or deep subsurface explorations to justify the setback. The County comment requested an updated report be prepared supporting the proposed setback. SCOPE Our scope of services was to evaluate the site conditions as a basis for assessing the recommended 75-foot setback distance from the top of the site’s high-bank shoreline bluff Ramage.McMinnRoad.RG June 30, 2023 page | 2 recommended in the SSGC geotechnical engineering report for this project. Specifically, the scope of services included the following: 1. Reviewing the available geologic, hydrogeologic, and geotechnical data for the site area; 2. Exploring surface conditions by reconnoitering the site and drilling two borings to depths of 21.5 feet and 60.8 feet below the existing grade; 3. Describing surface and subsurface conditions, including soil type and depth to groundwater; 4. Providing seismic design parameters, including 2018 IBC site class; 5. Performing a slope stability analysis using RocScience software SLIDE2 to verify the recommended setback distance of 75-feet from the high-bank shoreline bluff is sufficient for both static and pseudo-static (seismic) conditions; 6. Updating the assessment geologic hazards at the site in accordance with the Jefferson County Unified Development Title 18 Chapter 18.22 Critical Areas for Article V. Geologically Hazardous Areas, including an estimated annual bluff erosion rate; 7. Updating appropriate sections of the 2020 report by South Sound Geotechnical to address current site conditions and the current plans, including the seismic consideration section to the 2018 International Building Code (IBC); 8. Reviewing and providing our professional opinion on the provided stormwater drainage and septic plan; 9. Preparing this Geotechnical Engineering Report summarizing our site observations and conclusions, and our geotechnical recommendations and design criteria, along with the supporting data. The above scope of work was completed in accordance with our Proposal for Services dated June 7, 2023. We received written authorization for our services on June 12, 2023. SITE CONDITIONS Surface Conditions The project site consists of a single tax parcel listed at 750 McMinn Road in the Port Townsend area of Jefferson County, Washington. The site is in an area of existing large-lot, high-bank shoreline residential development and is situated along the top of the north facing high-bank shoreline bluff on the south side of the Strait of Juan De Fuca. As shown on the online tax parcel viewer for Jefferson County, the irregularly shaped parcel measures approximately 85 to 285 feet wide (north to south) by approximately 315 to 390 feet long (east to west) and encompasses approximately 1.46 acres as shown on Figure 3. The site is bounded by the shoreline of the Strait of Juan De Fuca to the north, an undeveloped parcel to the south, and by large lot residential development to the east and west. The description of the site topography is based on the 2-foot topographic contours shown on the Preliminary Grading and Storm Drainage Plan (Vader Engineering, 2023) and our site observations on June 19, 2023. The high bank bluff slopes up from the shoreline from northwest to southeast at about 130 percent with a vertical relief of 120 feet. According to the tax parcel viewer for Jefferson County, the east and west property boundaries extend across the mid slope of the shoreline bluff. From the top of the bluff, the site grades slope slightly up to the southeast and south at 2 to 14 percent to the south and east parcel boundaries with a total vertical relief of about 7 feet. The topographic relief across the site is on the order of about 80 feet. The site and shoreline topography Ramage.McMinnRoad.RG June 30, 2023 page | 3 are shown on an excerpt of the Preliminary Grading and Storm Drainage Plan (Vader Engineering, 2023) included as part of Figure 2. The general topography of the surrounding area is shown on the Site Vicinity Map, Figure 3 is based on 5-foot topographic contours from Jefferson County GIS. Vegetation across the site generally consists of Douglas Fir and ferns. No seeps, springs, or standing water was observed at the time of our site reconnaissance. No signs of active erosion or deep-seated landslide activity were observed at the site during our site reconnaissance on June 19, 2023, but our access was limited to the top of the high-bank shoreline bluff. We anticipate, based on our experience with similar shoreline bluffs, that active erosion is occurring on the face and at the toe of the bluff. Site Soils The USDA Natural Resources Conservation Survey (NRCS) Web Soil Survey mapping for Jefferson County (WA631) has the site soils as Clallam gravelly sandy loam (CmC) and coastal beaches (Co). An excerpt of the NRCS mapping for Jefferson County that covers the site and surrounding area is attached as Figure 4. • Clallam gravelly sandy loam (CmC): Mapped across most of the site, this soil is derived from basal till, forms on slopes of 0 to 15 percent, is considered a “moderate” erosion hazard when exposed, and is included in hydrologic soils group D. • Coastal Beaches (Co): Mapped as the soil on the northwest boundary of the parcel, this soil is derived from colluvium, forms on slopes of 1 to 5 percent, is “not rated” as an erosion hazard and is not included in a hydrologic soils group. Site Geology According to the Geologic Map of the Port Townsend South and Part of the Port Townsend North 7.5-minute Quadrangle, Jefferson, Washington by Henry W. Schassse and Stephen I. Slaughter (2005) the geology of the site and shoreline bluff is glacial till (Qgt), ablation till (Qgta), and glacial and nonglacial deposits, undivided (Qguc). The glacial and ablation till were deposited during the Vashon Stade of the Fraser Glaciation, some 12,000 to 15,000 years ago. The glacial and nonglacial deposits, undivided include geologic units from the Fraser Glaciation and from pre–Fraser non-glacial and glacial periods. A post-Fraser Glaciation landslide deposit (Qls) is mapped by the referenced geologic map on the face of the shoreline bluff northeast of the site. A digitized version of the above referenced geologic map completed by the Washington Geological Survey is attached as Figure 5. • Ablation till (Qgta): Mapped under the upper, flatter, south and southeast portions of the site, ablation till typically consists of a heterogeneous mixture of clay, silt, sand, and gravel that was deposited as subglacial and supraglacial melt-out (direct sediment deposition through the melting of stagnant or very slowly moving debris-rich ice) from the continental ice sheet associated with the Vashon Stade of the Fraser Glaciation. The ablation till is typically encountered in a loose condition, is considered non-consolidated, and exhibits moderate to low strength and compressibility characteristics when undisturbed. • Glacial till (Qgt): Mapped across the northeast and central portions of the site, glacial till typically consists of a heterogeneous mixture of clay, silt, sand, and gravel that was deposited at the base of the continental ice sheet associated with the Vashon Stade of the Fraser Glaciation. The glacial till was typically overridden by the ice sheet during advancement, and Ramage.McMinnRoad.RG June 30, 2023 page | 4 as such is considered over consolidated, is encountered in a dense to very dense condition, and exhibits high strength and low compressibility characteristics when undisturbed. • Glacial and nonglacial deposits, undivided (Qguc): Mapped across the northwest portion of the site and a portion of the shoreline bluff, the undivided glacial and nonglacial deposits typically consist of clay, silt, sand, gravel, glaciomarine drift and till where exposures are poor, and the deposits cannot be reliably divided into separate geologic units. These deposits were typically overridden by ice sheets during glacial periods, and as such are considered over consolidated, encountered in a dense to very dense condition, and exhibits high strength and low compressibility characteristics when undisturbed. Peat and other organics can be observed in the nonglacial deposits. • Landslide Deposits (Qls): Mapped to the northeast of the parcel on the face of the high-bank shoreline bluff, landslide deposits consist of unsorted gravel, sand, silt, clay, boulders, and organics typically deposited post Fraser Glaciation. These deposits are the result of mass wasting activity other than soil creep typically observed on very steep to over-steepened shoreline buffs, slopes with adverse geologic contacts (permeable soils over low permeable soils), slopes with groundwater seepage, or slopes with any combination of the three. We reviewed the Washington Geological Survey (WGS) protocol landslide mapping and other compiled landslide mapping groups for the site and surrounding area. The landslide mapping from these sources is shown on the Washington State Department of Natural Resources (WA DNR) Geologic Information Portal. The WGS protocol maps landslide landforms and landslide susceptibility using Lidar based on the criteria provided in the Protocol for Landslide Mapping from Lidar Data in Washington State (Slaughter, et al, 2017) and the Protocol for Shallow-Landslide Susceptibility Mapping (Burns and others, 2012). The other compiled landslide mapping is referenced from published geologic maps and reports. Where overlap of sources occurs, the WGS-protocol landslide mapping supersedes the other compiled landslide mapping. The compilation mapping shows landslide deposits, including the one on the referenced geologic map discussed above, extending across the lower northeastern portion of the bluff. An excerpt of the landslide compilation mapping as shown on the WA DNR Geologic Information Portal that covers the site and shoreline bluff is attached as Figure 6. We also reviewed the Washington State Department of Ecology (DOE) Coastal Atlas shoreline mapping for the surrounding area. The slope stability mapping was originally published as a hard copy map in the Coastal Zone Atlas of Washington between 1978 and 1980 and eventually digitized for reference. The digitized coastal atlas slope stability maps the upland portion of the site as “stable”. The high bank shoreline bluff is mapped as “unstable - old slide” which approximately corresponds to the WGS landslide compilation mapping. An excerpt of the Coastal Atlas map for slope stability of the site and surrounding area is included as Figure 7. Oblique shoreline photographs of the northwest shoreline of the Strait of Juan De Fuca from 1990, 2000, and 2016 that includes the site’s high bank shoreline bluff is attached as Figures 8a through 8c. The shoreline photo from 2000 shows a deep-seated landslide just northeast of the site. The dated sequences of images show the bluff is prone to surficial failure and bluff regression. The landslide compilation mapping as referenced above includes this landslide in the dataset. Ramage.McMinnRoad.RG June 30, 2023 page | 5 Subsurface Explorations On June 19, 2023, we visited the site and monitored the drilling of two borings to the depths of approximately 21.5 and 60.8 feet below existing site grades. The locations of the borings were selected by GeoResources personnel based on site access limitations, the proposed layout for the site, location of the recommended setback distance in the SSGC geotechnical engineering report for this project, and consideration for underground utilities. The borings were located by taping and pacing from features shown on publicly available data from Jefferson County GIS. As such, the locations of the explorations should only be considered accurate to the degree implied by our measuring methods. Table 1 summarizes the functional location, approximate elevation, and approximate termination elevation of the boring. TABLE 1: APPROXIMATE LOCATIONS AND DEPTHS OF EXPLORATIONS Boring Number Functional Location Surface Elevation1 (feet) Termination Depth (feet) Termination Elevation1 (feet) B-1 B-2 45 feet from top of high-bank shoreline bluff 110 feet southeast of boring B-1 132 136 60.8 21.5 71.2 114.5 Notes: 1 Preliminary Grading and Storm Drainage Plan for the Ramage residence by Vador Engineering, May 24, 2023. The boring rig was operated by a licensed drilling contractor working for GeoResources. Soil samples were obtained at 2½ and 5-foot depth intervals in accordance with Standard Penetration Test (SPT) as per the test method outlined by ASTM D1586. The SPT method consists of driving a standard 2-inch-diameter split-spoon sampler 18 inches into the soil with a 140-pound hammer. The number of blows required to drive the sampler through each 6-inch interval is counted, and the total number of blows during the final 12 inches of sampling is recorded as the Standard Penetration Resistance, or “SPT blow count”. If a total of 50 blows are recorded within any 6-inch interval (refusal), the driving is stopped, and the blow counts are recorded as 50 blows for the distance driven. The resulting SPT values indicate the relative density of granular soils and the relative consistency of cohesive soils. Each boring exploration was backfilled by the drilling subcontractor with bentonite chips in accordance with Washington State Department of Ecology requirements. An experienced and licensed geologist from our office continuously monitored the boring, maintained logs of the subsurface conditions encountered, obtained representative soil samples, and observed pertinent site features. Representative soil samples obtained from the borings were placed in sealed plastic bags and taken to our laboratory for further examination and testing as deemed necessary. The soils encountered were visually classified in accordance with the Unified Soil Classification System (USCS), which is included in Appendix A as Figure A-1. The descriptive logs of the borings are included as Figures A-2 and A-3. The location of each boring is shown on the attached Figure 2. Subsurface Conditions Our borings encountered subsurface conditions that were consistent with the soils logged in the test pit explorations from the SSGC geotechnical engineering report and generally confirmed the broad geologic mapping of undivided glacial and nonglacial deposits. Based on drilling conditions, Ramage.McMinnRoad.RG June 30, 2023 page | 6 density, and grain size, we split the Qguc soils into several distinct subunits. Each soil layer/type encountered at each boring location with the interpreted geologic unit for each soil layer is described below, while the thickness, depth, and elevation of each unit is described below in Table 2. TABLE 2: APPROXIMATE THICKNESS, DEPTHS, AND ELEVATION OF ENCOUNTERED SOIL TYPES Boring Number Thickness in feet of: Depth to Glacial and Non-Glacial Deposits (feet) Elevation1 of Glacial and Non-Glacial Deposits (feet) Topsoil Advance Glaciolacustrine Advance Outwash Glacial Till B-1 B-2 1 1 0 12.5 27 >9 40 NE 55 NE 77 NE Notes: 1 Preliminary Grading and Storm Drainage Plan for the Ramage residence by Vador Engineering, May 24, 2023. • Topsoil: At each boring location we observed about 1 foot of dark brown topsoil as the upper most soil layer, confirming the topsoil thickness noted in the test pit logs for the SSGC geotechnical engineering report. • Vashon Advance Glaciolacustrine Deposits: Underlying the topsoil at boring B-2 we observed about 5 feet of medium dense silty sand to poorly graded very fine sand with some silt mantling 7.5 feet of very stiff to hard grey to dark grey silt with some sand and variable amounts of gravels. We interpreted this soil to be advance glaciolacustrine deposits. Similar soil descriptions were noted in two exploration test pits from the SSGC geotechnical engineering report. • Vashon Advance Outwash: Underlying the topsoil at boring B-1 and the advance glaciolacustrine deposits at boring B-2 was a medium dense to dense brown, grey, to light grey poorly graded fine sand with some to trace silt and some to minor gravels. We interpret these soils to be fluvial advance outwash deposits and this deposit was observed to the full depth explored at boring B-2. Similar soils were described in one exploration test pit and an infiltration test pit from the SSGC geotechnical engineering report. • Glacial Till: Underlying the advance outwash at boring B-1 we observed about 25 feet of dense to very dense grey to dark grey gravelly silty sand in a moist condition. We interpreted this soil layer to be glacial till deposits. • Glacial and nonglacial deposits: Underlying the glacial till deposits at boring B-1 we observed a very dense grey silty sand in a dry to moist condition to the full depth explored. We interpreted this soil layer to be glacial and nonglacial deposits. Laboratory Testing Geotechnical laboratory tests were performed on select samples retrieved from the borings to estimate index engineering properties of the soils encountered. Laboratory testing included visual soil classification per ASTM D2488 and ASTM D2487, moisture content determinations per ASTM D2216, grain size analyses per ASTM D6913, washes per ASTMD1140-17 and Atterberg Limit determinations per ASTM D4318 standard procedures. Test results are included in Appendix B and summarized below in Table 3. Ramage.McMinnRoad.RG June 30, 2023 page | 7 TABLE 3: LABORATORY TEST RESULTS FOR ON-SITE SOILS Sample Soil Type Gravel Content (percent) Sand Content (percent) Silt/Clay Content (percent) Moisture Content (percent) B-1, S-11, 55.0ft SM 0.6 83.9 15.5 2.6 B-2, S-3+4, 5.0ft & 7.5ft CL ND ND 88.0 18.0 Sample Soil Type Liquid Limit (percent) Plastic Limit (percent) Plasticity Index (percent) Moisture Content (percent) B-2, S-3+4, 5.0ft & 7.5ft CL 44 21 23 18.0 Notes: ND = Not Determined, wash per ASTM D1170 Groundwater Conditions No groundwater seepage was observed during the drilling of each boring exploration. The drilling occurred during the dry season months (typically May to September), when groundwater levels are typically at their lowest. Groundwater seepage was noted in one test pit exploration from the SSGC geotechnical engineering report, at 9.5 feet below the existing grade. The test pit with the groundwater seepage was located about 450 feet southwest from boring B-2 and was also excavated during the dry season months. Based on the observed soil conditions, some areas of the site may be susceptible to perched groundwater during periods of prolonged wet weather. Some areas of the site appear to have a thin soil layer of silty sand or poorly graded sand overlying silt and clay soils at shallow depths, which can create the conditions needed for the development of a perched groundwater table. Silt and clay soils act as a low permeable soil and restrict the vertical movement of stormwater runoff. Perched groundwater tables are typically limited in thickness and can vary widely in lateral extent. Relatively rapid fluctuations of groundwater levels should be expected with seasonality and precipitation events. We reviewed two water well reports for private water wells installed at 620 McMinn Road and 690 McMinn Road. The water well reports were obtained from the Washington State Department of Ecology online well search tool. The water wells at 620 and 690 McMinn Road are located within 500 feet of the site and are approximately labeled on the attached Figure 3. The static groundwater levels for the wells were recorded at 142 feet (approximate elevation of -7 feet below sea level) and 131 feet (approximate elevation of 7 feet above sea level) below the top of the well, respectively. The surface elevations for each well were referenced from the Digital Terrain Model 137 from the Olympics South OSPW 2019 Lidar data. Each well log is included in the attached Appendix C. ENGINEERING CONCLUSIONS AND RECOMMENDATIONS Based on our site observations, data review, subsurface explorations, and engineering analysis, it is our opinion from a geotechnical standpoint that the construction of the proposed single-family residence is feasible provided the recommendations in this report are incorporated into the final design. Based on our site reconnaissance and geological assessment, the high bank Ramage.McMinnRoad.RG June 30, 2023 page | 8 shoreline bluff at the site meets the criteria for a landslide hazard area as defined by JCC 18.10.120. Pertinent conclusions and geotechnical recommendations regarding the design and construction of the proposed residence are presented below. Our services were provided to assist in the design of a single-family residence in proximity to the top of a high bank shoreline bluff. Our recommendations are intended to improve the overall stability of the site and to reduce the potential for future property damage related to earth movements, drainage, or erosion. However, all development on slopes involves risk, only part of which can be mitigated through qualified engineering and construction practices. Seismic Design The site is in the Puget Sound region of western Washington, which is seismically active. Seismicity in this region is attributed primarily to the interaction between the Pacific, Juan de Fuca, and North American plates. The Juan de Fuca plate is subducting beneath the North American plate at the Cascadia Subduction Zone (CSZ), creating the conditions for both intercrustal (between plates) and intracrustal (within a plate) earthquakes. In the following sections we discuss the design criteria and potential hazards associated with regional seismicity. Seismic Site Class Based on relative densities of soils observed in our boring explorations, we interpret the structural site conditions to correspond to a seismic Site Class “C” in accordance with the 2018 IBC documents and American Society of Civil Engineers (ASCE) standard 7-16. Single-family residences are typically classified as seismic rick category II. Design parameters The U.S. Geological Survey (USGS) completed probabilistic seismic hazard analyses (PSHA) for the entire country in November 1996, which were updated and republished in 2002 and 2008. We used the ATC Hazard by Location website to estimate seismic design parameters at the site. Table 4 summarizes the recommended design parameters. TABLE 4: 2018 IBC PARAMETERS FOR DESIGN OF SEISMIC STRUCTURES Spectral Response Acceleration (SRA) and Site Coefficients Short Period Risk Category II Mapped SRA Site Coefficients (Site Class C) Maximum Considered Earthquake SRA Design SRA Ss = 1.330g Fa = 1.200 SMS = 1.596g SDS = 1.064 g Peak Ground Acceleration The mapped peak ground acceleration (PGA) for this site is 0.569g. To account for site class the PGA is multiplied by a site amplification factor (FPGA) of 1.2. The resulting site modified peak ground Ramage.McMinnRoad.RG June 30, 2023 page | 9 acceleration (PGAM) is 0.683g. In general, estimating seismic earth pressures (kh) by the Mononobe- Okabe method is taken as 50 percent of the PGAM, or 0.342g. Seismic Hazards Earthquake-induced geologic hazards may include liquefaction, lateral spreading, slope instability, and ground surface fault rupture. Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength due to an increase in pore water pressure in soils. The increase in pore water pressure is induced by seismic vibrations. Liquefaction primarily affects geologically recent deposits of loose, uniformly graded, fine-grained sands and granular silts that are below the groundwater table. The soils observed in our boring explorations are glacially consolidated soils, therefore it is our opinion that the risk to the development from liquefaction is low to negligible. This is consistent with the Liquefaction susceptibility and site class maps of Washington State, by county: Washington Division of Geology and Earth Resources Open File Report 2004-20 by Palmer et. al. (2007) includes the site in the “very low” category for liquefaction susceptibility. An excerpt of the susceptibility mapping referenced above is attached as Figure 9. The Department of Natural Resources Geologic Hazards Map (Geologic Information Portal) infers an unnamed fault about 1,180 feet southwest of the site. The fault zone ends at the shoreline of the Strait of Juan De Fuca and continues northwest across the Strait of Juan De Fuca for about 4 miles. Tacoma fault zone to be more than 3 miles to the north and east of the site. An excerpt of the WA DNR fault hazard mapping showing the unnamed fault in proximity to the site is attached as Figure 10. No evidence of ground fault rupture was observed in the deeper boring exploration or out site reconnaissance. But it is possible evidence of a fault rupture is located beneath the final depth of our deepest boring exploration at the site. In our opinion, the proposed structure should have no greater risk of ground fault rupture than other structures located in the area. Slope Stability Analysis We analyzed the global slope stability of the site and high-bank shoreline bluff for profile A- A’. Both static and pseudo-static conditions were modeled for the slope stability analysis. The location of profile A-A’ was selected based on the location of our borings and proposed single-family residence to the shoreline bluff. The cross-section line A-A’ is labeled on the attached Figure 2. Methodology of Slope Stability Analysis The analysis was completed using SLIDE2 by RocScience software. SLIDE2 uses several methods to estimate the factor of safety (FS) of the stability of a slope by analyzing the shear and normal forces acting on a series of vertical “slices” that comprise a failure surface. Each vertical slice is treated as a rigid body; therefore, the forces and/or moments acting on each slice are assumed to satisfy static equilibrium (i.e., a limit equilibrium analysis). The FS is defined as the ratio of the forces available to resist movement to the forces of the driving mass. An FS of 1.0 means that the driving and resisting forces are equal; an FS less than 1.0 indicates that the driving forces are greater than the resisting forces (indicating failure). We used the Generalized Limit Equilibrium method using the Morgenstern-Price analysis, which satisfies both moment and force equilibrium, to search for the location of the most critical failure surfaces and their corresponding FS. The Morgenstern-Price methodology satisfies both moment and force equilibrium. The most critical surfaces are those with the lowest FS for a given loading condition and therefore are the most likely to move. Ramage.McMinnRoad.RG June 30, 2023 page | 10 Surface and Subsurface Profile for Profile A-A’ The surface profile for profile A-A’ was drawn using the 2-foot elevation contours shown on the Preliminary Grading and Storm Drainage Plan for the Ramage residence by Vader Engineering dated May 24, 2023. The subsurface geology of profile A-A’ was approximated by referencing the soils observed in our boring explorations, the test pit logs from the SSGC geotechnical engineering report, the water well reports within 500 feet of the site, and the Geologic Map of the Port Townsend South and Part of the Port Townsend North 7.5-minute Quadrangle, Jefferson, Washington by Henry W. Schassse and Stephen I. Slaughter (2005). The groundwater table was determined from the static groundwater elevations recorded in the water well reports from 620 and 690 McMinn Road. Material Properties for Stability Analysis For estimating the material properties for the slope stability analysis, we reviewed the Koloski, Schwarz, and Tubbs (1989) Geotechnical Properties of Geologic Materials, Engineering Geology in Washington, Washington Division of Geology and Earth Resources Bulletin 78 Volume I and the Edwin L. Harp, John A. Michael, and William T. Laprade (2006) Shallow-Landslide Hazard Map of Seattle, Washington, U.S. Geological Survey Open-File Report 2006-1139. We also reviewed the engineering properties for the various soils encountered on site per Chapter 5 of the 2019 Washington State Department of Transportation (WSDOT) Geotechnical Design Manual (M46-03.12). Table 5 summarizes the values published in the two referenced reports. Ramage.McMinnRoad.RG June 30, 2023 page | 11 TABLE 5: SOIL PROPERTIES FOR VARIOUS NATIVE SOIL TYPES ENCOUNTERED IN THE PUGET SOUND Deposit Source Dry Unit Weight (pcf) Friction Angle (degrees) Cohesion (psf) Glacial Till (ML, SM) Geotechnical Properties of Geologic Materials 120-140 35-45 1,000-4,000 Outwash (GW, GP, SW, SP, SM) 115-130 30-40 0-1,000 Beach deposits Shallow-Landslide Hazard Map of Seattle, Washington NA 34 0 Vashon recessional lacustrine deposits 24 ~400 Vashon till 36 ~2,000 Vashon advance outwash 34 ~250 Pre-Fraser fine grained deposits 26 ~600 Glacial Till WSDOT Geotechnical Design Manual (M46-03.12) 130-140 40 - 45 1,000-4,000 Outwash NA 40 - 45 01 Notes: 1 = GDM does not provide a range for outwash, but it states “near zero cohesion for clean deposits” Table 6 summarizes the estimated soil properties used in our slope stability analysis. A seismic load of 0.17g for till and firm glaciated soils, using the minimum general values of horizontal peak ground accelerations as defined in JCC 18.22.945.2.c and the blow counts observed during our boring explorations. TABLE 6: ASSIGNED SOIL STRENGTH PROPERTIES FOR SLOPE STABILITY ANALYSIS Deposit Unit Weight (pcf) Saturated Unit Weight (pcf) Friction Angle (degrees) Cohesion (psf) Beach Deposits 120 - 34 0 Advance Glaciolacustrine 110 - 24 400 Advance Outwash 125 - 40 100 Glacial Till 130 - 45 1500 Glacial & Nonglacial Deposits 110 120 36 600 Ramage.McMinnRoad.RG June 30, 2023 page | 12 Results of Stability Analysis Table 7 summarizes the factors of safety along the most critical slip surface identified from the stability analysis. The results of our slope stability analysis for cross section A-A’ and B-B’ are included in Appendix D. TABLE 7: GLOBAL STABILITY ANALYSES RESULTS Section Condition Loading Condition Lowest Factor of Safety Factor of Safety 75 feet bluff A-A’ Existing Static a = 0.17g for till, firm glaciated soils 1.2 1.0 1.5 1.1 Proposed Static a = 0.17g for till, firm glaciated soils 1.2 1.0 1.5 1.1 GEOLOGICALLY HAZARDOUS AREAS We completed an assessment of the geologically hazardous areas for the upland portion of the site and high-bank shoreline bluff. Jefferson County Title 18.22.510 defines geologically hazardous areas based on the following classification/designation: Erosion Hazard Areas (as defined in JCC 18.10.050) The site is located at the top of an over steepened high-bank shoreline bluff, likely created from erosion associated with wave, tidal, and wind energy. Accordingly, the site does meet the definition of an erosion hazard. The high bank shoreline bluff is a coastal erosion-prone area and should be considered an erosion hazard area. Erosion hazards can be mitigated by applying Best Management Practices outlined in the 2019 SWMMWW. We recommend that the single-family residence use conventional flow-control best management practices (BMPs) to address runoff from the residence. The location of the single- family residence is outside the conservative 120-year regression rate for the high-bank shoreline bluff, thus maintaining at least a 120-year useful life of the structure from coastal erosion hazards. The estimated regression limit for 120 years using a conservative yearly regression rate of 6-inches per year is labeled on the attached Figure 11. Landslide Hazard Areas (as defined in JCC 18.10.120) The high bank shoreline bluff at the site meets five indicators of a landslide hazard area as defined by Jefferson County Title 18.10.120(A) (indicators i, ii, iii, iv, and ix). Our slope stability analysis of the high bank shoreline bluff for existing configuration had factors of safety below 1.5 and 1.1 respectively for the static and dynamic conditions. The high bank shoreline bluff is a landslide hazard area. The landslide hazard area is labeled on the attached Figure 11. Ramage.McMinnRoad.RG June 30, 2023 page | 13 Buffer and Setback from Landslide Hazard Area Based on the result of our slope stability analysis, we support a 60-foot vegetated buffer with an additional 15-foot building setback from the edge of the vegetated buffer. Grading, decks, and septic systems are allowed within the 15-foot building setback. The buffer and setback are labeled on the attached Figure 2 and 11. Stormwater Management Jefferson County has adopted the 2019 Washington State Department of Ecology Stormwater Management Manual for Western Washington for use in stormwater management and design. Per the provided preliminary storm drainage plans for the single-family residence, an infiltration trench measuring 4 feet (width) x 4 feet (depth) x 40 feet (length) is proposed within the 15-foot building setback and is located approximately 50 feet from the top of the shoreline high bank bluff. We assess the high bank shoreline bluff as a landslide hazard area and a 200-foot setback from a landslide hazard area is required unless evaluated by a geotechnical professional. The proposed infiltration trench is located within the proposed setback associated with the recommended buffer. The proximity of the trench to the top of the slope was not discussed in the original SSGC (Verify) report. Converting the infiltration trench to a dispersion would limit the amount of point-sourced infiltration but the dispersion trench would not have the prerequisite 100- foot vegetated flow path to the slope. However, flowing through the vegetated buffer would provide protection from erosion and allow for runoff to be taken up by the root mass. Alternatively, we would recommend an HDP tightline down the bluff conveying runoff to discharge on the beach at the toe of the bluff. We understand the County has pushed back on the use of tightline conveyance systems to shorelines because of the need for special shoreline permits. Our experience is that such tightline conveyance systems are permitted through a Shoreline Exemption permit because they are an auxiliary appurtenant structure, but that a Hydraulic Activity Permit (HPA) would be required by the Department of Fish and Wildlife. Additionally, installation of the spreader pipe at the toe of the bluff may also be challenging given the difficult access to the beach. “ LIMITATIONS We have prepared this report for use by Mr. Richard Ramage and other members of the design team, for use in the design of a portion of this project. The data used in preparing this report and this report should be provided to prospective contractors for their bidding or estimating purposes only. Our report, conclusions and interpretations are based on our subsurface explorations, data from others and limited site reconnaissance, and should not be construed as a warranty of the subsurface conditions. Variations in subsurface conditions are possible between the explorations and may also occur with time. A contingency for unanticipated conditions should be included in the budget and schedule. Sufficient monitoring, testing and consultation should be provided by our firm during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether earthwork and foundation installation activities comply with contract plans and specifications. Ramage.McMinnRoad.RG June 30, 2023 page | 14 If there are any changes in the loads, grades, locations, configurations or type of facilities to be constructed, the conclusions and recommendations presented in this report may not be fully applicable. If such changes are made, we should be given the opportunity to review our recommendations and provide written modifications or verifications, as appropriate. Ramage.McMinnRoad.RG June 30, 2023 page I 15 We appreciate the opportunity to be of service to you on this project. If you have any questions or comments, please do not hesitate to call at your earliest convenience. Respectfully submitted, GeoResources, LLC ErikJ. Fina, LG Senior Staff Geologist Keith S. Schembs, LEG Principal EJF:KSS:EWH/ejf DoclD: Ramage.McMinnRoad.RG Attachments: Figure 1: Site Location Map Figure 2: Site & Exploration Plan Figure 3: Site Vicinity Map Figure 4: NRCS Soils Map Figure 5: Geologic Map Figure 6: WGS Landslide Compilation Mapping Figure 7: WA DOE Coastal Atlas Figure 8a-8c: -Shoreline Oblique Photos Figure 9: Liquefaction Susceptibility Map Figure 10: Fault Hazard Mapping Figure 11: Geologically Hazardous Areas Appendix A: Subsurface Explorations Appendix B: Laboratory Test Results Appendix C: Water Well Reports Appendix D: Slope Stability Results Eric W. Heller, PE Senior Geotechnical Engineer GEORESOURCES earth science & geotechnical engineering Approximate Site Location Figure created from Jefferson County Public Land Records GIS website (https://gisweb.jeffcowa.us/LandRecords/) Not to Scale Site Location Map Proposed Single-Family Residence 750 McMinn Road Port Townsend, Washington PN: 002014003 Doc ID: Ramage.McMinnRoad.F Jun 2023 Figure 1 A ASetbackBuffer A A' B-2 B-1 Doc ID: Ramage.McMinnRoad.F July 2023 Preliminary Site Plan prepared by Vader Engineering, dated March 14, 2023.Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN 0 25 50 75 10012.5 Feet Proposed Single-Family Residence750 McMinn RoadJefferson County, WashingtonPN: 002014003 1 inch = 50 feet Figure 2 Site & Exploration PlanLegend A Number and approximate location of boring Cross Section Setback Buffer Approximate Site Location Figure created from Jefferson County Public Land Records GIS website (https://gisweb.jeffcowa.us/LandRecords/) Not to Scale Site Vicinity Map Proposed Single-Family Residence 750 McMinn Road Port Townsend, Washington PN: 002014003 Doc ID: Ramage.McMinnRoad.F Jun 2023 Figure 3 620 McMinn Rd 690 McMinn Rd 2014003 Source: Esri, Maxar, Earthstar Geographics, IGN, and the GIS User Community Approximate Site Location Figure created from Web Soil Survey (http://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx) Soil Type Soil Name Parent Material Slopes Erosion Hazard Hydrologic Soils Group CmC Clallam gravelly sandy loam Basal till 0 to 15 Moderate D Co Coastal beaches Colluvium 1 to 5 Not rated -- HuC Hoypus gravelly loamy sand Glacial outwash 0 to 15 Moderate A Not to Scale NRCS Soils Map Proposed Single-Family Residence 750 McMinn Road Port Townsend, Washington PN: 002014003 Doc ID: Ramage.McMinnRoad.F Jun 2023 Figure 4 CmC HuC Co 2014003 Source: Esri, Maxar, Earthstar Geographics, IGN, and the GIS User Community Approximate Site Location A Washington Geological Survey digitized version of the Geologic Map of the Port Townsend South and Part of the Port Townsend North 7.5-Minute Quadrangles, Jefferson County, Washington by Henry W. Schasse and Stephen I. Slaughter (2005). Symbol Geologic Unit Qb Beach deposits Qls Landslide deposits Qgoi Ice-contact stratified drift Qgt Lodgment till Qgta Ablation till Qguc Glacial and nonglacial deposits, undivided Not to Scale Geologic Map Proposed Single-Family Residence 750 McMinn Road Port Townsend, Washington PN: 002014003 Doc ID: Ramage.McMinnRoad.F Jun 2023 Figure 5 wtr Qgt(a) Qgt Qgo(i)Qguc Qguc QlsQb Qls 2014003 Approximate Site Location An excerpt from the WGS database set for Landslide Compilation, overlayed on World Imagery and a DTM from the Olympics South ospw 2019 Lidar Not to Scale WGS Landslide Compilation Mapping Proposed Single-Family Residence 750 McMinn Road Port Townsend, Washington PN: 002014003 Doc ID: Ramage.McMinnRoad.F Jun 2023 Figure 6 Qls Qls 2014003 Source: Esri, Maxar, Earthstar Geographics, IGN, and the GIS User Community 1:24,000-scale Landslides from Geologic Mapping Approximate Site Location An excerpt from the WA DOE Coastal Zone Atlas Map (https://apps.ecology.wa.gov/coavstalatlas/tools/Map.aspx) Not to Scale WA DOE Coastal Atlas Proposed Single-Family Residence 750 McMinn Road Port Townsend, Washington PN: 002014003 Doc ID: Ramage.McMinnRoad.F Jun 2023 Figure 7 Stable slope Unstable-old slideFBDZ LtoR 2014003 Source: Esri, Maxar, Earthstar Geographics, IGN, and the GIS User Community Approximate Site Location Shoreline oblique photo from 1990 Not to Scale Shoreline Oblique Photos Proposed Single-Family Residence 750 McMinn Road Port Townsend, Washington PN: 002014003 Doc ID: Ramage.McMinnRoad.F Jun 2023 Figure 8a Approximate Site Location Shoreline oblique photo from 2000 Not to Scale Shoreline Oblique Photos Proposed Single-Family Residence 750 McMinn Road Port Townsend, Washington PN: 002014003 Doc ID: Ramage.McMinnRoad.F Jun 2023 Figure 8b Approximate Site Location Shoreline oblique photo from 2016 Not to Scale Shoreline Oblique Photos Proposed Single-Family Residence 750 McMinn Road Port Townsend, Washington PN: 002014003 Doc ID: Ramage.McMinnRoad.F Jun 2023 Figure 8c Approximate Site Location Palmer, Stephen P.; Magsino, Sammantha L.; Bilderback, Eric L.; Poelstra, James L.; Folger, Derek S.; Niggemann, Rebecca A., 2007, Liquefaction susceptibility and site class maps of Washington State, by county: Washington Division of Geology and Earth Resources Open File Report 2004-20, [78 plates, 45 p. text]. http://www.dnr.wa.gov/publications Not to Scale Liquefaction Susceptibility Map Proposed Single-Family Residence 750 McMinn Road Port Townsend, Washington PN: 002014003 Doc ID: Ramage.McMinnRoad.F Jun 2023 Figure 9 Approximate Site Location An excerpt from the Washington State Department of Natural Resources Geologic Information Portal (https://geologyportal.dnr.wa.gov/) Not to Scale Fault Hazard Mapping Proposed Single-Family Residence 750 McMinn Road Port Townsend, Washington PN: 0020140037 Doc ID: Ramage.McMinnRoad.F Jun 2023 Figure 10 2014003 U n n a me d f a u lt (cla s s B ) © OpenStreetMap (and) contributors, CC-BY-SA 1,180 feet SW of Site SetbackBuffer120 Yr Regression LimitFigure 11Doc ID: Ramage.McMinnRoad.F July 2023 Preliminary Site Plan prepared by Vader Engineering, dated March 14, 2023.Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN 0 25 50 75 10012.5 Feet Proposed Single-Family Residence750 McMinn RoadJefferson County, WashingtonPN: 002014003 Geologically Hazardous Areas 1 inch = 50 feet Legend Setback Buffer Shoreline Regression Limit Landslide and Erosion Hazard Area Appendix A Subsurface Explorations SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP SYMBOL GROUP NAME COARSE GRAINED SOILS GRAVEL CLEAN GRAVEL GW WELL-GRADED GRAVEL, FINE TO COARSE GRAVEL GP POORLY-GRADED GRAVEL More than 50% Of Coarse Fraction Retained on No. 4 Sieve GRAVEL WITH FINES GM SILTY GRAVEL GC CLAYEY GRAVEL More than 50% Retained on No. 200 Sieve SAND CLEAN SAND SW WELL-GRADED SAND, FINE TO COARSE SAND SP POORLY-GRADED SAND More than 50% Of Coarse Fraction Passes No. 4 Sieve SAND WITH FINES SM SILTY SAND SC CLAYEY SAND FINE GRAINED SOILS SILT AND CLAY INORGANIC ML SILT CL CLAY Liquid Limit Less than 50 ORGANIC OL ORGANIC SILT, ORGANIC CLAY More than 50% Passes No. 200 Sieve SILT AND CLAY INORGANIC MH SILT OF HIGH PLASTICITY, ELASTIC SILT CH CLAY OF HIGH PLASTICITY, FAT CLAY Liquid Limit 50 or more ORGANIC OH ORGANIC CLAY, ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT NOTES: SOIL MOISTURE MODIFIERS: 1. Field classification is based on visual examination of soil Dry- Absence of moisture, dry to the touch in general accordance with ASTM D2488-90. Moist- Damp, but no visible water 2. Soil classification using laboratory tests is based on ASTM D6913. Wet- Visible free water or saturated, usually soil is obtained from below water table 3. Description of soil density or consistency are based on interpretation of blow count data, visual appearance of soils, and or test data. Unified Soils Classification System Proposed Single-Family Residence 750 McMinn Road Port Townsend, Washington PN: 002014003 Doc ID: Ramage.McMinnRoad.F Jun 2023 Figure A-1 0 5 10 15 20 25 30 130 125 120 115 110 105 100 Blow counts overstated first 6- inches, sampling on gravel or cobble Upper contact of Glacial Till Dark brown topsoil Cuttings visually classifed as silty SAND (SM) with some gravels (Vashon Advance Outwash) Brownish grey poorly graded fine SAND with some gravel and silt (SP-SM) (medium dense, moist) Brownish grey gravelly poorly graded fine SAND with some silt (SP-SM) interbedded with grey silt (medium dense, dry to moist) Light grey poorly graded fine SAND with some gravel and trace silt (SP) (dense, dry to moist) Light grey poorly graded fine to very fine SAND with some silt and trace gravel (SP-SM) (dense, dry to moist) Ligh grey poorly graded SAND with some gravel and silt (dense, dry to moist) Grey gravelly silty SAND (SM) (very dense, dry to moist) (Glacial Till) 7 8 10 9 12 16 9 15 34 43 20 26 12 18 21 21 32 40 72 LOG OF BORING B-1 Proposed Single-Family Residence750 McMinn RoadPort Townsend, Washington 1. Refer to log key for definition of symbols, abbreviations, and codes 2. USCS disination is based on visual manual classification and selected lab testing 3. Groundwater level, if indicated, is for the date shown and may vary 4. NE = Not Encountered 5. ATD = At Time of Drilling Drilling Company:Boretec, Inc.Logged By:EJF Drilling Method:Hollow Stem Auger Drilling Date:06/19/2023 Drilling Rig:EC Track Rig Datum:NAVD88 Sampler Type:Spilt Spoon Elevation:132 feet Hammer Type:Rope Pulled Cathead Termination Depth:60.8 feet Hammer Weight:140lbs Latitude: Notes:Longitude: Topsoil Silty sand Poorly graded sand with silt Poorly graded sand Silty sand and gravel Sheet 1 of JOB:Ramage.McMinnRoad FIG.A-2Depth(feet)Elevation (feet)Exploration notes Soil description SPT BlowcountsSamplerSymbolTest Results 1020304050Penetration - (blows per foot) % Water Content % Fines (<0.075mm)Plastic Limit Liquid Limit Groundwater2 35 40 45 50 55 60 95 90 85 80 75 70 Dark grey gravelly silty SAND (SM) (dense, moist to wet) Groundwater seepage? Dark grey gravelly silty SAND (SM) (very dense, moist) Grey silty SAND (SM) (very dense, moist) (Glacial and Nonglacial Deposits) Grey silty SAND (SM) (very dense, dry to moist) (Termination Depth - 06/19/2023) 19 22 26 18 32 49 50/4" 50/3" 48 50/5" 42 50/4" 81 150 200 120 150 LOG OF BORING B-1 Proposed Single-Family Residence750 McMinn RoadPort Townsend, Washington 1. Refer to log key for definition of symbols, abbreviations, and codes 2. USCS disination is based on visual manual classification and selected lab testing 3. Groundwater level, if indicated, is for the date shown and may vary 4. NE = Not Encountered 5. ATD = At Time of Drilling Drilling Company:Boretec, Inc.Logged By:EJF Drilling Method:Hollow Stem Auger Drilling Date:06/19/2023 Drilling Rig:EC Track Rig Datum:NAVD88 Sampler Type:Spilt Spoon Elevation:132 feet Hammer Type:Rope Pulled Cathead Termination Depth:60.8 feet Hammer Weight:140lbs Latitude: Notes:Longitude: Topsoil Silty sand Poorly graded sand with silt Poorly graded sand Silty sand and gravel Sheet 2 of JOB:Ramage.McMinnRoad FIG.A-2Depth(feet)Elevation (feet)Exploration notes Soil description SPT BlowcountsSamplerSymbolTest Results 1020304050Penetration - (blows per foot) % Water Content % Fines (<0.075mm)Plastic Limit Liquid Limit Groundwater2 0 5 10 15 20 25 30 135 130 125 120 115 110 105 Upper Contact Vashon Advance Outwash Dark brown topsoil Cuttings visually classifed as silty SAND (SM) with some gravels (Vashon Advance Glaciolacustrine) Brownish grey gravelly poorly graded very fine SAND with some silt (SP-SM) (medium dense, moist) Grey CLAY with some silt and trace sand (CL) (hard, dry to moist) LL=44, PL=21, PI=23 (S-2 and S-3 combined) Grey CLAY with some silt and trace sand (CL) (very stiff, dry to moist) Dark grey CLAY with some silt and trace sand (CL) (very stiff, moist) silty sand at tip spilt spoon and in shoe Grey silty SAND with some gravels (SM) (dense, dry to moist) (Vashon Advance Outwash) Brown gravelly poorly graded SAND with trace silt (SP) (very dense, dry to moist) (Termination Depth - 06/19/2023) 7 8 7 7 13 20 8 12 15 43 20 26 16 17 23 15 24 32 88.0 LOG OF BORING B-2 Proposed Single-Family Residence750 McMinn RoadPort Townsend, Washington 1. Refer to log key for definition of symbols, abbreviations, and codes 2. USCS disination is based on visual manual classification and selected lab testing 3. Groundwater level, if indicated, is for the date shown and may vary 4. NE = Not Encountered 5. ATD = At Time of Drilling Drilling Company:Boretec, Inc.Logged By:EJF Drilling Method:Hollow Stem Auger Drilling Date:06/19/2023 Drilling Rig:EC Track Rig Datum:NAVD88 Sampler Type:Spilt Spoon Elevation:136 feet Hammer Type:Rope Pulled Cathead Termination Depth:21.5 feet Hammer Weight:140lbs Latitude: Notes:Longitude: Topsoil Silty sand Poorly graded sand with silt Low plasticity clay Poorly graded sand Sheet 1 of JOB:Ramage.McMinnRoad FIG.A-3Depth(feet)Elevation (feet)Exploration notes Soil description SPT BlowcountsSamplerSymbolTest Results 1020304050Penetration - (blows per foot) % Water Content % Fines (<0.075mm)Plastic Limit Liquid Limit Groundwater1 Appendix B Laboratory Test Results These results are for the exclusive use of the client for whom they were obtained. They apply only to the samples tested and are not indicitive of apparently identical samples.Tested By: Checked By: Particle Size Distribution Report PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 0.0 0.6 0.8 14.6 68.5 15.56 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM D 6913 & ASTM D 1140) Opening Percent Spec.*Pass? Size Finer (Percent)(X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Source of Sample: B-1 Depth: 55 Sample Number: S-11 Client: Project: Project No:Figure silty sand 0.375 #4 #10 #20 #40 #60 #100 #200 100.0 99.4 98.6 95.9 84.0 49.4 29.0 15.5 NP NV NP SM A-2-4(0) 0.4952 0.4339 0.2936 0.2526 0.1556 Natural Moisture: 6/19/23 6/22/23 MAW KSS PM 6/19/23 Richard Ramage Proposed Single-Family Residence Ramage.McMinnRoad PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) GeoResources, LLC Fife, WA B-1 These results are for the exclusive use of the client for whom they were obtained. They apply only to the samples tested and are not indicitive of apparently identical samples.Tested By: Checked By: Particle Size Distribution Report PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 88.06 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Test Results (ASTM D 6913 & ASTM D 1140) Opening Percent Spec.*Pass? Size Finer (Percent)(X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Source of Sample: B-2 Depth: 7.5 Sample Number: S-3 Client: Project: Project No:Figure Clay with some silt #200 88.0 21 44 23 CL Natural Moisture: 6/19/23 6/22/23 MAW KSS PM 6/19/23 Richard Ramage Proposed Single-Family Residence Ramage.McMinnRoad PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) GeoResources, LLC Fife, WA B-2a These results are for the exclusive use of the client for whom they were obtained. They apply only to the samples tested and are not indicitive of apparently identical samples.Tested By: Checked By: GeoResources, LLC Fife, WA Client: Project: Project No.:Figure Richard Ramage Proposed Single-Family Residence Ramage.McMinnRoad B-2b SYMBOL SOURCE NATURAL USCSSAMPLEDEPTHWATERPLASTICLIQUIDPLASTICITY NO.CONTENT LIMIT LIMIT INDEX (%)(%)(%)(%) SOIL DATAPLASTICITY INDEX0 10 20 30 40 50 60 LIQUID LIMIT 0 10 20 30 40 50 60 70 80 90 100 110 CL-ML CL or OL CH or O H ML or OL MH or OH Dashed line indicates the approximate upper limit boundary for natural soils 47 LIQUID AND PLASTIC LIMITS TEST REPORT B-2 S-3 7.5 18.1 21 44 23 CL Appendix C Water Well Reports Appendix D Slope Stability Results 1.2051.4921.205WW1.2051.4921.205RuHu TypeWater SurfacePhi (deg)Cohesion (psf)Strength TypeSat. Unit Weight (lbs/ft3)Unit Weight (lbs/ft3)ColorMaterial Name0None340Mohr-Coulomb120Beach Deposits0None24400Mohr-Coulomb110Silty CLAY with some sand (ML) BC 33 to 46 (Vashon Advance Glaciolacustrine)0None40100Mohr-Coulomb125Poorly graded SAND with some to minor gravel and some to trace silt (SP, SP-SM) BC 18 to 49 (Vashon Advance Outwash)0None451500Mohr-Coulomb130Gravelly silty SAND (SM) BC > 50 (Glacial Till)Automatically CalculatedWater Surface36600Mohr-Coulomb120110Silty SAND (SM) BC > 50 (Glacial and Nonglacial Deposits, undivided)Boring B-1Boring B-277.4553002001000-100-50050100150200250300350400450500ScenarioStatic ConditionsGroupExisting ConfigurationCompanyGeoResources, LLCDrawn ByEJF/MAEFile NameRamage.McMinnRoad.slmdDate6/19/2023, 10:06:01 AMProjectSlide2 - An Interactive Slope Stability ProgramSLIDEINTERPRET 9.026 WW1.0931.0930.9500.9500.9500.950RuHu TypeWater SurfacePhi (deg)Cohesion (psf)Strength TypeSat. Unit Weight (lbs/ft3)Unit Weight (lbs/ft3)ColorMaterial Name034 None0Mohr-Coulomb120Beach Deposits024 None400Mohr-Coulomb110Silty CLAY with some sand (ML) BC 33 to 46 (Vashon Advance Glaciolacustrine)040 None100Mohr-Coulomb125Poorly graded SAND with some to minor gravel and some to trace silt (SP, SP-SM) BC 18 to 49 (Vashon Advance Outwash)045 None1500Mohr-Coulomb130Gravelly silty SAND (SM) BC > 50 (Glacial Till)Automatically CalculatedWater 36Surface600Mohr-Coulomb120110Silty SAND (SM) BC > 50 (Glacial and Nonglacial Deposits, undivided)72.461Boring B-2Boring B-1 0.173002001000-100-50050100150200250300350400450500ScenaPserioudo-Static Conditions for till, firm glaciated soils (JeffersonGroupExisting ConfigurationCompanyDrawn ByEJF/MAEFile NameRamage.McMinnRoad.slmdDate6/19/2023, 10:06:01 AMProjectSlide2 - An Interactive Slope Stability ProgramSLIDEINTERPRET 9.026 1.2051.4811.205WW 2000.00 lbs/ft21.2051.4811.205Boring B-2Boring B-1RuHu TypeWater SurfacePhi (deg)Cohesion (psf)Strength TypeSat. Unit Weight (lbs/ft3)Unit Weight (lbs/ft3)ColorMaterial Name0None500Mohr-Coulomb150Concrete0None340Mohr-Coulomb120Beach Deposits0None24400Mohr-Coulomb110Silty CLAY with some sand (ML) BC 33 to 46 (Vashon Advance Glaciolacustrine)0None40100Mohr-Coulomb125Poorly graded SAND with some to minor gravel and some to trace silt (SP, SP-SM) BC 18 to 49 (Vashon Advance Outwash)0None451500Mohr-Coulomb130Gravelly silty SAND (SM) BC > 50 (Glacial Till)Automatically CalculatedWater Surface36600Mohr-Coulomb120110Silty SAND (SM) BC > 50 (Glacial and Nonglacial Deposits, undivided)Proposed Footprint of Residence75Ō Recommended Buffer + Setback250200150100500-50-50050100150200250300350400ScenarioStatic ConditionsGroupProposed Site Configuration CompanyGeoResources, LLCDrawn ByEJF/MAEFile NameRamage.McMinnRoad.slmdDate6/19/2023, 10:06:01 AMProjectSlide2 - An Interactive Slope Stability ProgramSLIDEINTERPRET 9.026 WW 2000.00 lbs/ft21.0991.0990.9500.9500.9500.950Boring B-Boring B-172.528RuHu TypeWater SurfacePhi (deg)Cohesion (psf)Strength TypeSat. Unit Weight (lbs/ft3)Unit Weight Color(lbs/ft3)Material Name0None500Mohr-Coulomb150Concrete0None340Mohr-Coulomb120Beach Deposits0None24400Mohr-Coulomb110Silty CLAY with some sand (ML) BC 33 to 46 (Vashon Advance Glaciolacustrine)0None40100Mohr-Coulomb125Poorly graded SAND with some to minor gravel and some to trace silt (SP, SP-SM) BC 18 to 49 (Vashon Advance Outwash)0None451500Mohr-Coulomb130Gravelly silty SAND (SM) BC > 50 (Glacial Till)Automatically CalculatedWater 36Surface600Mohr-Coulomb120110Silty SAND (SM) BC > 50 (Glacial and Nonglacial Deposits, undivided) 0.173002001000-1000100200300400500ScenaPserioudo-Static Conditions for till, firm glaciated soils (JeffersonGroupProposed Site Configuration CompanyDrawn ByEJF/MAEFile NameRamage.McMinnRoad.slmdDate6/19/2023, 10:06:01 AMProjectSlide2 - An Interactive Slope Stability ProgramSLIDEINTERPRET 9.026 South Sound Geotechnical Consulting September 8, 2020 Mr. Richard Ramage c/o Chambers Bay Construction 3800A Bridgeport Way, Suite 162 Subject: Geotechnical Engineering Report 750 McMinn Road Development Port Townsend, Washington SSGC Project No. 20068 Mr. Ramage, South Sound Geotechnical Consulting (SSGC) has completed a geotechnical assessment for the planned development on the above address property in Port Townsend, Washington. Our services have been completed in general conformance with our proposal P20058 (dated July 29, 2020) and authorized per signature of our agreement for services. Our scope of services included completion of three test pits and one infiltration test, laboratory testing, engineering analyses, and preparation of this report. PROJECT INFORMATION The property is a long and narrow lot with the long axis oriented in a generally north-south direction. The McMinn Road easement bisects the property with the proposed residence on the north side of the lot. A second residence may be located in the southern portion of the lot in the future We anticipate conventional spread footing foundations will be used for support of new structures. Infiltration facilities will be used to support stormwater control. SITE CONDITIONS The northern boundary of the property is along the shore of the Strait of Juan De Fuca. It is characterized with a bluff along the shoreline having a height of approximately 100 (+/-) feet per Google satellite imagery. The remainder of the property is generally level with about 10 (+/-) feet of elevation change. Vegetation consists of generally mature forest growth (conifer trees) north of McMinn Road, with mixed forest and brush in the southern portion. SUBSURFACE CONDITIONS Subsurface conditions were characterized by completing three test pits and one infiltration test on the site on August 8, 2020. Test holes were advanced to final depths between about 8 and 10 feet below existing ground surface. Approximate locations of test pits and infiltration test sites are shown on Figure 1, Exploration Plan. Logs of these explorations are provided in Appendix A. A summary description of observed subgrade conditions is provided below. Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 2 Soil Conditions Topsoil/duff was observed below the surface and extended to an average depth of about 1 foot at the test locations. Native soil below the topsoil in the northern portion of the site (Test pit TP-1 and infiltration test PIT-1 consisted of an upper silty sand with variable gravel. This soil was in a loose condition and extended to a depth of around 2.5 feet. Gravelly sand with trace silt to sand was below the upper layer. This soil was in a loose to medium dense condition and extended to the termination depth of these excavations. Native soil below the topsoil/cuff in test pits TP-2 and TP-3 consisted of silt/clay with some fine sand. This soil was in a stiff condition and extended to depths of 4 in TP-2 and to the termination depth of 10 feet in pit TP-3. Sand with some silt and gravel was below the silt/clay in test pit TP- 2 and extended to the termination depth of 10 feet. Groundwater Conditions Groundwater was observed in test pit TP-2 at a depth of about 9.5 feet at the time of excavation. This water was associated with the sand and gravel below the upper silt/clay soil. Groundwater was not observed in the remaining excavations. Groundwater levels will vary throughout the year based on seasonal precipitation and on- and off-site drainage patterns. Geologic Setting Soils on the site are mapped as “Clallam gravelly sandy loam” per the USDA Soil Conservation Service map of Jefferson County. Clallam soil reportedly formed on glacial terraces. Granular soils in the explorations appear to generally conform with the mapped soil type, with less fines. However, the upper clay and silt observed in test pits TP-2 and TP-3 are interpreted to be a different soil type. The bluff on the north side of the lot is mapped as Pre-Fraser (last glacial advance) glacial drift and till per the Washington State DNR “Geologic Map of the Port Townsend South and Part of the Port Townsend North 7.5-minute Quadrangle, Jefferson County, Washington”, dated 2005. The level portion of the site (above the bluff) is mapped as ablation till. GEOTECHNICAL DESIGN CONSIDERATIONS Planned development is considered feasible based on observed soil conditions in the explorations. Properly prepared native soils can be used for support of conventional spread footing foundations, floor slabs, and pavements. Currently, the new planned residence will be on the order of 100 feet south of the bluff. Infiltration to assist in stormwater control is considered feasible in the granular soils observed in test pit TP-1 and the PIT-1 site. However, infiltration in the silt/clay soils observed in test pits TP-2 and TP-3 is not feasible. Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 3 Recommendations presented in the following sections should be considered general and may require modifications at the time of construction. They are based upon the subsurface conditions observed in the explorations and the assumption that finish site grades will be similar to existing grades. It should be noted subsurface conditions across the site can vary from those depicted on the exploration logs and can change with time. Therefore, proper site preparation will depend upon the weather and soil conditions encountered at the time of construction. We recommend SSGC review final plans and further assess subgrade conditions at the time of construction, as warranted. General Site Preparation Site grading and earthwork should include procedures to control surface water runoff. Grading the site without adequate drainage control measures may negatively impact site soils, resulting in increased export of impacted soil and import of fill materials, thereby potentially increasing the cost of the earthwork and subgrade preparation phases of the project. Site grading should include removal (stripping) of topsoil/duff and any fill encountered, or very loose or soft soils in building and pavement areas. Topsoil extended to a depth of about 1 foot in the test holes but may be deeper or shallower in other areas. Final stripping depths can only be determined at the time of construction. Subgrades should consist of firm, undisturbed native soils following stripping. General Subgrade Preparation Subgrades in building footprints and pavement areas should consist of firm, undisturbed native soils. We recommend exposed subgrades in building and conventional pavement areas are proofrolled using a large roller, loaded dump truck, or other mechanical equipment to assess subgrade conditions following stripping. Proofrolling efforts should result in the upper 1 foot of subgrade soils in building and conventional pavement areas achieving a firm and unyielding condition (or a compaction level of at least 95 percent of the maximum dry density (MDD) per the ASTM D1557 test method). Wet, loose, or soft subgrades that pump or cannot achieve this compaction level should be removed (over-excavated) and replaced with structural fill. The depth of over-excavation should be based on soil conditions at the time of construction. A representative of SSGC should be present to assess subgrade conditions during proofrolling. Grading and Drainage Positive drainage should be provided during construction and maintained throughout the life of the development. Surface water should not be allowed to flow into construction excavations or fill areas. Structural Fill Materials The suitability of soil for use as structural fill will depend on the gradation and moisture content of the soil when it is placed. Soils with higher fines content (soil fraction passing the U.S. No. 200 sieve) will Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 4 become sensitive with higher moisture content. It is often difficult to achieve adequate compaction if soil moisture is outside of optimum ranges for soils that contain more than about 5 percent fines. Site Soils: Organic rich soils (topsoil/duff) and any fill are not considered suitable as structural fill. Native sand and gravel soils observed are considered suitable for structural fill, if properly moisture conditioned. The silt/clay is not considered suitable for structural fill as it is moisture sensitive and will be difficult to achieve optimum moisture content and uniform compaction. Import Fill Materials: We recommend imported structural fill placed during dry weather consist of material which meets the specifications for Gravel Borrow as described in Section 9-03.14(1) of the 2018 Washington State Department of Transportation (WSDOT) Specifications for Road, Bridge, and Municipal Construction manual (Publication M 41-10). Gravel Borrow should be protected from disturbance if exposed to wet conditions after placement. During wet weather, or for backfill on wet subgrades, import soil suitable for compaction in wetter conditions should be provided. Imported fill for use in wet conditions should conform to specifications for Select Borrow as described in Section 9-03.14(2), or Crushed Surfacing per Section 9-03.9(3) of the 2018 WSDOT M-41 manual, with the modification that a maximum of 5 percent by weight shall pass the U.S. No. 200 sieve for these soil types. Structural fill placement and compaction is weather-dependent. Delays due to inclement weather are common, even when using select granular fill. We recommend site grading and earthwork be scheduled for the drier months of the year. Structural fill should not consist of frozen material. Structural Fill Placement We recommend structural fill is placed in lifts not exceeding about 10 inches in loose measure. It may be necessary to adjust lift thickness based on site and fill conditions during placement and compaction. Finer grained soil used as structural fill and/or lighter weight compaction equipment may require significantly thinner lifts to attain required compaction levels. Granular soil with lower fines contents could potentially be placed in thicker lifts (1 foot maximum) if they can be adequately compacted. Structural fill should be compacted to attain the recommended levels presented in Table 1, Compaction Criteria. Table 1. Compaction Criteria Fill Application Compaction Criteria* Footing areas 95 % Upper 2 feet in pavement areas, flatwork, and utility trenches 95 % Below 2 feet in pavement areas, flatwork, and utility trenches 92 % Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 5 Utility trenches or general fill in non-paved or -building areas 90 % *Per the ASTM D 1557 test method. Trench backfill within about 2 feet of utility lines should not be over-compacted to reduce the risk of damage to the line. In some instances, the top of the utility line may be within 2 feet of the surface. Backfill in these circumstances should be compacted to a firm and unyielding condition. We recommend fill procedures include maintaining grades that promote drainage and do not allow ponding of water within the fill area. The contractor should protect compacted fill subgrades from disturbance during wet weather. In the event of rain during structural fill placement, the exposed fill surface should be allowed to dry prior to placement of additional fill. Alternatively, the wet soil can be removed. We recommend consideration is given to protecting haul routes and other high traffic areas with free-draining granular fill material (i.e. sand and gravel containing less than 5 percent fines) or quarry spalls to reduce the potential for disturbance to the subgrade during inclement weather. Earthwork Procedures Conventional earthmoving equipment should be suitable for earthwork at this site. Earthwork may be difficult during periods of wet weather or if elevated soil moisture is present. Excavated site soils may not be suitable as structural fill depending on the soil moisture content and weather conditions at the time of earthwork. If soils are stockpiled and wet weather is anticipated, the stockpile should be protected with securely anchored plastic sheeting. If stockpiled soils become wet and unusable, it will become necessary to import clean, granular soils to complete wet weather site work. Wet or disturbed subgrade soils should be over-excavated to expose firm, non-yielding, non-organic soils and backfilled with compacted structural fill. We recommend the earthwork portion of this project be completed during extended periods of dry weather. If earthwork is completed during the wet season (typically October through April) it may be necessary to take extra measures to protect subgrade soils. If earthwork takes place during freezing conditions, we recommend the exposed subgrade is allowed to thaw and re-compacted prior to placing subsequent lifts of structural fill. Alternatively, the frozen soil can be removed to unfrozen soil and replaced with structural fill. The contractor is responsible for designing and constructing stable, temporary excavations (including utility trenches) as required to maintain stability of excavation sides and bottoms. Excavations should be sloped or shored in the interest of safety following local and federal regulations, including current OSHA excavation and trench safety standards. Temporary excavation cuts should be sloped at inclinations of 1.5H:1V (Horizontal:Vertical) or flatter, unless the contractor can demonstrate the safety of steeper cut slopes. It should be noted cleaner sand and gravel soils have the tendency to cave into open excavations. Shoring may be necessary for deeper utility trenches on this site. Permanent cut and fill slopes should be inclined at grades of 2H:1V, or flatter. Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 6 A geotechnical engineer and accredited materials testing firm should be retained during the construction phase of the project to observe earthwork operations and to perform necessary tests and observations during subgrade preparation, placement and compaction of structural fill, and backfilling of excavations. Foundations Foundations can be placed on firm native soils or on a zone of structural fill above prepared subgrades as described in this report. The following recommendations are for conventional spread footing foundations: Bearing Capacity (net allowable): 2,000 pounds per square foot (psf) for footings supported on firm native soils or structural fill over native subgrades prepared as described in this report. Footing Width (Minimum): 16 inches (Strip) 24 inches (Column) Embedment Depth (Minimum): 18 inches (Exterior) 12 inches (Interior) Settlement: Total: < 1 inch Differential: < 1/2 inch (over 30 feet) Allowable Lateral Passive Resistance: 300 psf/ft* (below 12 inches) Allowable Coefficient of Friction: 0.35* *These values include a factor of safety of approximately 1.5. The net allowable bearing pressures presented above may be increased by one-third to resist transient, dynamic loads such as wind or seismic forces. Lateral resistance to footings should be ignored in the upper 12-inches from exterior finish grade unless restricted. Foundation Construction Considerations All foundation subgrades should be free of water and loose soil prior to placing concrete, and should be prepared as recommended in this report. Concrete should be placed soon after excavating and compaction to reduce disturbance to bearing soils. Should soils at foundation level become excessively dry, disturbed, saturated, or frozen, the affected soil should be removed prior to placing concrete. We recommend SSGC observe foundation subgrades prior to placement of concrete. Foundation Drainage Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 7 Ground surface adjacent foundations should be sloped away to facilitate drainage. We recommend footing drains are installed around perimeter footings. Footing drains should include a minimum 4- inch diameter perforated rigid plastic or metal drain line installed along the exterior base of the footing. The perforated drain lines should be connected to a tight line pipe that discharges to an approved storm drain receptor. The drain line should be surrounded by a zone of clean, free-draining granular material having less than 5 percent passing the No. 200 sieve or meeting the requirements of section 9-03.12(2) “Gravel Backfill for Walls” in the 2018 WSDOT (M41-10) manual. The free- draining aggregate zone should be at least 12 inches wide and wrapped in filter fabric. The granular fill should extend to within 6 inches of final grade where it should be capped with compacted fill containing sufficient fines to reduce infiltration of surface water into the footing drains. Alternately, the ground surface can be paved with asphalt or concrete. Cleanouts are recommended for maintenance of the drain system. On-Grade Floor Slabs On-grade floor slabs should be placed on native soils or structural fill prepared as described in this report. We recommend a modulus subgrade reaction of 175 pounds per square inch per inch (psi/in) for native soil or compacted granular structural fill over properly prepared native soil. We recommend a capillary break is provided between the prepared subgrade and bottom of slab. Capillary break material should be a minimum of 4 inches thick and consist of compacted clean, free- draining, well graded coarse sand and gravel. The capillary break material should contain less than 5 percent fines, based on that soil fraction passing the U.S. No. 4 sieve. Alternatively, a clean angular gravel such as No. 7 aggregate per Section 9-03.1(4) C of the 2018 WSDOT (M41-10) manual could be used for this purpose. We recommend positive separations and/or isolation joints are provided between slabs and foundations, and columns or utility lines to allow independent movement where needed. Backfill in interior trenches beneath slabs should be compacted in accordance with recommendations presented in this report. A vapor retarder should be considered beneath concrete slabs that will be covered with moisture sensitive or impervious coverings (such as tile, wood, etc.), or when the slab will support equipment or stored materials sensitive to moisture. We recommend the slab designer refer to ACI 302 and/or ACI 360 for procedures and limitations regarding the use and placement of vapor retarders. Seismic Considerations Recommended seismic parameters and values in Table 2 are based on the 2015 International Building Code (IBC) Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 8 Table 2. Seismic Parameters PARAMETER VALUE 2015 International Building Code (IBC) Site Classification1 D Ss Spectral Acceleration for a Short Period 1.293 S1 Spectral Acceleration for a 1-Second Period 0.525g Fa Site Coefficient for a Short Period 1.00 Fv Site Coefficient for a 1-Second Period 1.5 1 Note: In general accordance with 2015 International Building Code, Section 1613.3.1 for risk categories I,II,III. IBC Site Class is based on the estimated characteristics of the upper 100 feet of the subsurface profile. Ss, S1, Fa, and Fv values based on the OSHPD Seismic Design Maps website. Liquefaction Soil liquefaction is a condition where loose, typically granular soils located below the groundwater surface lose strength during ground shaking, and is often associated with earthquakes. The Jefferson County “Liquefaction Susceptibility” map identifies this area as having a very low to low risk to liquefaction. Subgrade soils consist of glacially consolidated drift and till and are not considered highly susceptible to liquefaction. Infiltration Characteristics We understand stormwater control will use infiltration facilities, where feasible. General assessment of infiltration potential of native soils was performed by completing one small-scale Pilot Infiltration Test (PIT) on the site per the 2012 WDOE Stormwater Management Manual for Western Washington. Test PIT-1 was completed in native gravelly sand on the north side of McMinn Road. Results of the infiltration test is presented in Table 3. Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 9 Table 3. Infiltration Test Results Infiltration Test No. Depth of Test from Surface (feet) Soil Type Field Infiltration Rate (in/hr) Corrected Infiltration Rate (in/hr) Correction Factors* (CFv/CFt/CFm) PIT-1 3 Native Gravel/Sand 6 2.1 (0.8/0.5/0.9) *Correction Factors from the 2012 WDOE SWMM for Western Washington. The tested infiltration rate from PIT-1 is considered appropriate for the observed native soil. We recommend an average long-term design rate of 2 inches per hour (in/hr) for the native glacial soils to account for soil variability. Should final site grades remain similar to existing, it appears that sufficient separation from groundwater or impermeable soils should be achievable for conventional infiltration systems and individual roof trench systems in the site, north of the McMinn Road easement. Future development in the southern portion of the lot may require retention/detention or shallow dispersion systems to facilitate stormwater control due to the silt/clay observed in the test pits in this area. Cation Exchange Capacity (CEC) and organic content tests were completed on a sample from the bottom of infiltration test hole. Test results are summarized in Table 4. Table 4. CEC and Organic Content Results Test Location, Sample Number, Depth CEC Results (milliequivalents) CEC Required* (milliequivalents) Organic Content Results (%) Organic Content Required* (%) PIT-1, S-1, 3 feet 7.4 ≥ 5 1.45 ≥1.0 *Per the 2012 WDOE SWMM for Western Washington. Organic content and CEC test results satisfy state criteria on the tested sample. GEOLOGIC ASSESSMENT - CRITICAL AREA SLOPES The following documents were reviewed as part of our critical area assessment of the bluff on the north boundary of the property: Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 10 ◼ U.S. Department of Agriculture Soil Conservation Service, Soil Survey of Jefferson County Area, Washington. ◼ Jefferson County Municipal Code (JCMC). ◼ Washington State DNR Geologic Information Portal Web Site. ◼ Washington State DNR “Geologic Map of the Port Townsend South and Part of the Port Townsend North 7.5-minute Quadrangle, Jefferson County, Washington”, dated 2005. ◼ Washington State Coastal Atlas Maps. ◼ Google Maps Document Summary Per Chapter 18.22 of the JCMC, the bluff along the north property boundary is in a landslide hazard area. The bluff is near vertical and has relief of around 100 feet. The Coastal Atlas map depicts the area within approximately 150 (+/-) feet of the bluff as unstable, with the remainder of the site as stable. The Washington DNR portal site and geologic map of the area does show the bluff throughout the area has experienced localized slides. SLOPE CONDITIONS SSGC completed a reconnaissance of the bluff on August 10, 2020 as part of our geotechnical evaluation of the property. Our observations include: ▪ The bluff consists of exposed glacially consolidated soil with exposed soil and some brush and tree growth. Mature conifer trees at the top of the bluff exhibited generally straight trunks. Evidence of recent slides on the bluff across the property boundaries was not observed. ▪ Evidence of existing slope movement (such as tension cracks, down-dropped blocks etc.) was not observed on the site above the bluff at the time of our visit. ▪ Seepage or surface water was not observed on the bluff at the time of our site visit. Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 11 GEOLOGIC HAZARD AREAS DISCUSSION Chapter 18.22 of the JCMC addresses critical areas and hazard protection standards. Based upon our review of the previously referenced documents and our field observations, we offer the following statements regarding the landslide hazard areas as described in the JCMC. Soils on the northwest-facing bluff generally consist of dense glacially consolidated deposits. Evidence of recent landslide activity (tension cracks, down-dropped blocks, etc.) was not observed on the bluff at the time of our site visit. Currently, the planned residence will be on the order of 100 feet away from the top of the bluff. This setback is considered suitable based on observed and mapped conditions of the bluff. It is our opinion the development can be constructed without adversely affecting the stability of the bluff. Based on provided information, no planned construction activities will occur within 100 feet of the bluff. We recommend roof stormwater trenches for the proposed residence are located to the south of the building (away from the bluff). Concentrated runoff should not be allowed to flow onto the bluff. Erosion Hazard The proposed development will not require earthwork or alteration to the steep northwest-facing bluff. With regard to construction for this development, it is our opinion that Best Management Practices (BMP) for erosion control (silt fencing, straw bales, etc.) can be utilized such that the risk of off-site transport of sediment is limited during construction. Additional erosion control measures may be necessary if earthwork is scheduled during the wetter seasons. All erosion control provisions should be in compliance with Jefferson County regulations to reduce the risk of off-site transport of sediments. Exposed soils following any construction should be vegetated as soon as possible. Irrigation should be minimized on or near steeper slopes. Temporary and permanent stormwater control measures should prevent concentrated flow onto the northwest-facing bluff. REPORT CONDITIONS This report has been prepared for the exclusive use of Mr. Richard Ramage and his agents for specific application to the project discussed, and has been prepared in accordance with generally accepted geotechnical engineering practices in the area. No warranties, either express or implied, are intended or made. The analysis and recommendations presented in this report are based on observed soil conditions and test results at the indicated locations, and from other geologic information discussed. This report does not reflect variations that may occur across the site, or due to the modifying effects of construction or weather or other natural events. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided. Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 12 This report was prepared for the planned type of development of the site as discussed herein. It is not valid for third party entities or alternate types of development on the site without the express written consent of SSGC. If development plans change we should be notified to review those changes and modify our recommendations as necessary. The scope of services for this project does not include any environmental or biological assessment of the site including identification or prevention of pollutants, hazardous materials, or conditions. Other studies should be completed if the owner is concerned about the potential for contamination or pollution. We appreciate the opportunity to work with you on this project. Please contact us if additional information is required or we can be of further assistance. Respectfully, South Sound Geotechnical Consulting DRAFT Timothy H. Roberts, P.E. Member/Geotechnical Engineer Attachments: Figure 1 – Exploration Plan Appendix A – Field Exploration Procedures and Exploration Logs Appendix B – Laboratory Testing and Results Unified Soil Classification System N South Sound Geotechnical Consulting P.O. Box 39500 Lakewood, WA 98496 (253) 973-0515 Figure 1 – Exploration Plan 750 McMinn Road Port Townsend, WA SSGC Project #20068 Approximate Test Pit Location PIT - 1 TP - 1 PIT - 1 Approximate Infiltration Test Location Scale: NTS Base map Google Maps Legend PIT-1 TP-2 TP-1 TP-3 Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 A-1 Appendix A Field Exploration Procedures and Exploration Logs Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 Field Exploration Procedures Our field exploration for this project included three test pits and one infiltration test completed on August 8, 2020. The approximate locations of the explorations are shown on Figure 1, Exploration Plan. The exploration locations were determined by pacing from site features. Ground surface elevations referenced on the logs were inferred from Google Satellite imagery. Test pit locations and elevations should be considered accurate only to the degree implied by the means and methods used. A client provided backhoe and operator dug the test holes. Soil samples were collected and stored in moisture tight for further assessment and laboratory testing. Explorations were backfilled with excavated soils and tamped when completed. Please note that backfill in the explorations may settle with time. Backfill material located in building or road areas should be re-excavated and recompacted, or replaced with structural fill. The following logs indicate the observed lithology of soils and other materials observed in the explorations at the time of excavation. Where a soil contact was observed to be gradational, our log indicates the average contact depth. Our logs also indicate the approximate depth to groundwater (where observed at the time of excavation), along with sample numbers and approximate sample depths. Soil descriptions on the logs are based on the Unified Soil Classification System. Project: McMinn Rd Residence SSGC Job # 20068 EXPLORATION LOGS PAGE 1 OF 2 Location: Port Townsend, WA TEST PIT LOGS FIGURE A-1 South Sound Geotechnical Consulting PIT-1, TP-1 through TP-3 Logged by: THR Infiltration Test PIT-1 Depth (feet) Material Description 0 – 1 1 – 2.5 2.5 – 8 Topsoil/Duff: Silt, sand, with roots: Loose, damp, brown. Silty SAND with occasional gravel: Loose, damp, light brown. (SM) Gravelly SAND with trace silt: Loose to medium dense, damp, gray. (SP) (Sample S-1 @ 3 feet) Test hole completed at approximately 8 feet on 8/10/20. Infiltration test completed at 3 feet. Groundwater not observed at time of excavation. Approximate surface elevation: 140 feet Test Pit TP-1 Depth (feet) Material Description 0 – 1 1 – 2.5 2.5 – 8 8 – 9.5 Topsoil/Duff: Silt, sand, with roots: Loose, damp, brown. Silty SAND with occasional gravel: Loose, damp, light brown. (SM) Gravelly SAND with trace silt: Loose to medium dense, damp, gray. (SP) (Sample S-1 @ 3 feet) SAND with some silt and occasional gravel: Medium dense, moist, gray. (SM) (Sample S-2 @ 8 feet) Test pit completed at approximately 9.5 feet on 8/10/20. Groundwater not observed at time of excavation. Approximate surface elevation: 138 feet Project: McMinn Rd Residence SSGC Job # 20068 EXPLORATION LOGS PAGE 2 OF 2 Location: Port Townsend, WA TEST PIT LOGS FIGURE A-1 South Sound Geotechnical Consulting PIT-1, TP-1 through TP-3 Logged by: THR Test Pit TP-2 Depth (feet) Material Description 0 – 1 1 – 4 4 – 10 Topsoil/Duff: Silt, sand, with roots: Loose, damp, brown. CLAY/SILT with some fine sand: Stiff, moist, gray. (CL/ML) SAND with gravel and trace to some silt: Medium dense, moist, brownish gray. (SP) Test pit completed at approximately 10 feet on 8/10/20. Groundwater observed at 9.5 feet at time of excavation. Approximate surface elevation: 145 feet Test Pit TP-3 Depth (feet) Material Description 0 – 1 1 – 10 Topsoil/Duff: Silt, sand, with roots: Loose, damp, brown. CLAY/SILT with some fine sand: Stiff, moist, gray. (CL/ML) Test pit completed at approximately 10 feet on 8/10/20. Groundwater not observed at time of excavation. Approximate surface elevation: 143 feet Geotechnical Engineering Report SSGC Vista Heights Development – 66th Street East Fife, WA SSGC Project No. 20024 April 23, 2020 C-1 Appendix B Laboratory Testing and Results Geotechnical Engineering Report SSGC 750 McMinn Road Port Townsend, WA SSGC Project No. 20068 September 8, 2020 B-1 Laboratory Testing Select soil samples were tested for organic content and cation exchange capacity (CEC) by Northwest Agricultural Consultants of Kennewick, Washington. Gradation tests were completed by Construction Testing Laboratories (CTL) of Puyallup, Washington. Results of the laboratory testing are included in this appendix. Report shall not be reproduced except in full without the written approval of the Laboratory. Report pertains only to the material tested.Tested By: R Rowden Checked By: C Pedersen Particle Size Distribution Report ASTM C-117, C-136 PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0 0 23 10 24 38 56 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200SIEVE PERCENT SPEC.*PASS? SIZE FINER PERCENT (X=NO) Material Description Atterberg Limits Classification Remarks Source of Sample: PIT #1 Sample Number: 20-1116 Date: Client: Project: Project No:Figure Grab Sample, S-1 Sampled at 3'3/4" 1/2" 3/8" #4 #8 #10 #16 #40 #100 #200 100 96 90 77 70 67 62 43 8 5.3 Report: #02 Sampled by: Client South Sound Geotechnical McMinn (20068) 8665 PL=LL=PI= USCS=AASHTO= *(no specification provided) 08-10-20 Construction Testing Laboratories 400 Valley Ave. NE, Suite #102 Puyallup WA, 98372 Tel. (253) 383-8778 Report shall not be reproduced except in full without the written approval of the Laboratory. Report pertains only to the material tested.Tested By: M Armstrong Checked By: C Pedersen Particle Size Distribution Report ASTM C-117, C-136 PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0 6 28 23 28 13 26 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200SIEVE PERCENT SPEC.*PASS? SIZE FINER PERCENT (X=NO) Material Description Atterberg Limits Classification Remarks Source of Sample: TP-1 Sample Number: 20-1114 Date: Client: Project: Project No:Figure Grab Sample, S-1 Sampled at 3'1" 3/4" 1/2" 3/8" #4 #8 #10 #16 #40 #100 #200 100 94 87 83 66 47 43 34 15 3 2.2 SP Report: #01 Sampled by: Client South Sound Geotechnical McMinn (20068) 8665 PL=LL=PI= USCS=AASHTO= *(no specification provided) 08-10-20 Construction Testing Laboratories 400 Valley Ave. NE, Suite #102 Puyallup WA, 98372 Tel. (253) 383-8778 2545 W Falls Avenue Kennewick, WA 99336 509.783.7450 www.nwag.com lab@nwag.com Sample ID Organic Matter Cation Exchange Capacity Pit-1, S-1 1.45% 7.4 meq/100g Method ASTM D2974 EPA 9081 South Sound Geotechnical Consulting PO Box 39500 Lakewood, WA 98496 Report: 52354-1-1 Date: August 24, 2020 Project No: 20068 Project Name: McMinn Rd UNIFIED SOIL CLASSIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Soil Classification Group Symbol Group NameB Coarse Grained Soils More than 50% retained on No. 200 sieve Gravels More than 50% of coarse fraction retained on No. 4 sieve Clean Gravels Less than 5% finesC Cu 4 and 1 Cc 3E GW Well-graded gravelF Cu 4 and/or 1 Cc 3E GP Poorly graded gravelF Gravels with Fines More than 12% finesC Fines classify as ML or MH GM Silty gravelF,G, H Fines classify as CL or CH GC Clayey gravelF,G,H Sands 50% or more of coarse fraction passes No. 4 sieve Clean Sands Less than 5% finesD Cu 6 and 1 Cc 3E SW Well-graded sandI Cu 6 and/or 1 Cc 3E SP Poorly graded sandI Sands with Fines More than 12% finesD Fines classify as ML or MH SM Silty sandG,H,I Fines Classify as CL or CH SC Clayey sandG,H,I Fine-Grained Soils 50% or more passes the No. 200 sieve Silts and Clays Liquid limit less than 50 inorganic PI 7 and plots on or above “A” lineJ CL Lean clayK,L,M PI 4 or plots below “A” lineJ ML SiltK,L,M organic Liquid limit - oven dried 0.75 OL Organic clayK,L,M,N Liquid limit - not dried Organic siltK,L,M,O Silts and Clays Liquid limit 50 or more inorganic PI plots on or above “A” line CH Fat clayK,L,M PI plots below “A” line MH Elastic SiltK,L,M organic Liquid limit - oven dried 0.75 OH Organic clayK,L,M,P Liquid limit - not dried Organic siltK,L,M,Q Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat A Based on the material passing the 3-in. (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay. D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay E Cu = D60/D10 Cc = 6010 2 30 DxD )(D F If soil contains 15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. HIf fines are organic, add “with organic fines” to group name. I If soil contains 15% gravel, add “with gravel” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” whichever is predominant. L If soil contains 30% plus No. 200 predominantly sand, add “sandy” to group name. M If soil contains 30% plus No. 200, predominantly gravel, add “gravelly” to group name. N PI 4 and plots on or above “A” line. O PI 4 or plots below “A” line. P PI plots on or above “A” line. Q PI plots below “A” line. 2045 Ramage | 44 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com 2045 Ramage | 45 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Appendix D Calculations CONVEYANCE CONVEYANCE capacity was checked with a run-off calculation typically refered to as the Rational Method ,which uses the formula: Reach Capacity CFS Design Flow CFS Velocity FPS Special Materials or Specifications 6” Conveyance pipes 0.52 <0.5 cfs for Entrance Drive basin Up to 2.99 no Q = CIA Where C = .98 for pavement I = 2.5 for 100 year rainfall intensity from NOAA isopluvials, below. = 2.0 for 25 year from Washington State isopluvials by MGS = 1.0 for 2 year from Washington State isopluvials by MGS A = Area in Acres = (~20,000 SF)/43,560 SF/AC = 0.46 Results for the various storm events were: Q 100 = 0.133 cfs Q 25 = 0.094 cfs Q 2 = 0.057 cfs The capacity of the pipe was calculated with the Chezy-Manning’s method. Each of the 2-yr, 25 yr and 100 yr conditions achieves self-cleaning velocities of over 2 FPS and none of them fill the pipe to capacity or cause a backwater condition. 2045 Ramage | 46 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Table 2a: Conveyance Calculations 2045 Ramage | 47 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Table 3b: Conveyance Calculations 2045 Ramage | 48 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com MGS Flood Model: Pre-Developed Conditions 2045 Ramage | 49 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com MGS Flood Model: Post-Developed Conditions 2045 Ramage | 50 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Figure – NOAA Isopluvial 100 year rainfall intensity 2045 Ramage | 51 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Figure – Precipitation Map 2 year rainfall intensity 2045 Ramage | 52 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com Figure –Precipitation Map 25 year rainfall intensity 2045 Ramage | 53 VaderENGINEERING, LLC 6817 27th ST W, #65353 Tacoma, WA 98466 www.vaderengineering.com INFILTRATION An infiltration trench was sized to 40 LF in length, 4-foot depth, and 4-foot width to manage 100% of the runoff from the site. This was sized using the MGS Flood continuous hydrology model. For sizing purposes, the trench model size was 30 LF for an area of 0.750 Ac. The proposed infiltration trench is 40 LF for an area, which by this model requires a minimum 36.7 LF trench for the actual area of 0.9177 Ac. Note, the MGS Flood report shows that runoff flows from the proposed development will be completely managed by the proposed infiltration trench. Please see final MGS reports attached after this page. The figure on the right shows how the water surface elevation is maximized. The figure on the right shows the probability of flows overtopping trench. ————————————————————————————————— MGS FLOOD PROJECT REPORT Program Version: MGSFlood 4.55 Program License Number: 201910004 Project Simulation Performed on: 02/23/2023 1:18 PM Report Generation Date: 02/23/2023 1:24 PM ————————————————————————————————— Input File Name: 2045 Ramage.23.02.23.fld Project Name: 2045 Ramage Analysis Title: Infiltration sizing Comments: - Uplands only, slope not modelled. - Precipitation input of 32 higher than mapped at 22 in/yr. ————————————————————————————————— Routing Not Up to Date. Changes were Made to Model Input Since Last Routing was Performed Click the Simulate Tab and then Click Route to remove this message ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 1 Full Period of Record Available used for Routing Precipitation Station : 95003205 Puget West 32 in_5min 10/01/1939-10/01/2097 Evaporation Station : 951032 Puget West 32 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 0.149 0.149 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 0.149 0.149 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Converted area pnly ---------- -------Area (Acres) -------- Outwash Forest 0.149 ---------------------------------------------- Subbasin Total 0.149 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Impervious ---------- -------Area (Acres) -------- Impervious 0.149 ---------------------------------------------- Subbasin Total 0.149 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: Trench Link Type: Infiltration Trench Downstream Link: None Trench Type : Trench on Embankment Sideslope Trench Length (ft) : 30.00 Trench Width (ft) : 6.00 Trench Depth (ft) : 6.00 Trench Bottom Elev (ft) : 100.00 Trench Rockfill Porosity (%) : 30.00 Constant Infiltration Option Used Infiltration Rate (in/hr): 2.10 **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Converted area pnly 27.584 _____________________________________ Total: 27.584 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Impervious 0.000 Link: Trench 51.518 _____________________________________ Total: 51.518 Total Predevelopment Recharge is Less than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.175 ac-ft/year, Post Developed: 0.326 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ********** Link: Trench ********** Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 51.61 Inflow Volume Including PPT-Evap (ac-ft): 51.61 Total Runoff Infiltrated (ac-ft): 51.52, 99.82% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 0.04 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 99.82% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: Converted area pnly Scenario Postdeveloped Compliance Link: Trench *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 1.057E-04 2-Year 0.000 5-Year 1.158E-04 5-Year 0.000 10-Year 1.179E-04 10-Year 1.044E-03 25-Year 1.188E-04 25-Year 2.764E-02 50-Year 1.193E-04 50-Year 3.065E-02 100-Year 1.197E-04 100-Year 3.253E-02 200-Year 1.291E-04 200-Year 3.544E-02 500-Year 1.417E-04 500-Year 3.936E-02 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals **** Flow Duration Performance **** Excursion at Predeveloped 50%Q2 (Must be Less Than or Equal to 0%): 0.0% PASS Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): 0.0% PASS Maximum Excursion from Q2 to Q50 (Must be less than 10%): 99999.0% FAIL Percent Excursion from Q2 to Q50 (Must be less than 50%): 100.0% FAIL ------------------------------------------------------------------------------------------------- FLOW DURATION DESIGN CRITERIA: FAIL ------------------------------------------------------------------------------------------------- **** LID Duration Performance **** Excursion at Predeveloped 8%Q2 (Must be Less Than 0%): 0.0% PASS Maximum Excursion from 8%Q2 to 50%Q2 (Must be Less Than 0%): 0.0% PASS ------------------------------------------------------------------------------------------------- MEETS ALL LID DURATION DESIGN CRITERIA: PASS ------------------------------------------------------------------------------------------------- ————————————————————————————————— MGS FLOOD PROJECT REPORT Program Version: MGSFlood 4.55 Program License Number: 201910004 Project Simulation Performed on: 02/24/2023 7:04 PM Report Generation Date: 02/24/2023 7:23 PM ————————————————————————————————— Input File Name: 2045 Ramage.23.02.24.4x40.fld Project Name: 2045 Ramage Analysis Title: Infiltration sizing Comments: - Uplands only, slope not modelled. - Precipitation input of 32 higher than mapped at 22 in/yr. ————————————————————————————————— Routing Not Up to Date. Changes were Made to Model Input Since Last Routing was Performed Click the Simulate Tab and then Click Route to remove this message ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 1 Full Period of Record Available used for Routing Precipitation Station : 95003205 Puget West 32 in_5min 10/01/1939-10/01/2097 Evaporation Station : 951032 Puget West 32 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 0.750 0.750 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 0.750 0.750 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Converted area pnly ---------- -------Area (Acres) -------- Outwash Forest 0.750 ---------------------------------------------- Subbasin Total 0.750 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 2 ---------- Subbasin : Impervious ---------- -------Area (Acres) -------- Impervious 0.149 ---------------------------------------------- Subbasin Total 0.149 ---------- Subbasin : Pervious ---------- -------Area (Acres) -------- Outwash Forest 0.302Outwash Pasture 0.300 ---------------------------------------------- Subbasin Total 0.602 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 2 ------------------------------------------ Link Name: Trench w max overflow Flow Control 91% Link Type: Structure Downstream Link Name: POC Prismatic Pond Option Used Pond Floor Elevation (ft) : 100.00 Riser Crest Elevation (ft) : 104.00 Max Pond Elevation (ft) : 105.00 Storage Depth (ft) : 4.00 Pond Bottom Length (ft) : 40.0 Pond Bottom Width (ft) : 4.0 Pond Side Slopes (ft/ft) : L1= 0.00 L2= 0.00 W1= 0.00 W2= 0.00 Bottom Area (sq-ft) : 160. Area at Riser Crest El (sq-ft) : 160. (acres) : 0.004 Volume at Riser Crest (cu-ft): 640. (ac-ft) : 0.015 Area at Max Elevation (sq-ft) : 160. (acres) : 0.004 Vol at Max Elevation (cu-ft): 800. (ac-ft) : 0.018 Constant Infiltration Option Used Infiltration Rate (in/hr): 2.10 Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 24.00 Common Length (ft) : 0.000 Riser Crest Elevation : 104.00 ft Hydraulic Structure Geometry Number of Devices: 0 ------------------------------------------ Link Name: POC Link Type: Structure Downstream Link: None Prismatic Pond Option Used Pond Floor Elevation (ft) : 100.00 Riser Crest Elevation (ft) : 103.00 Max Pond Elevation (ft) : 104.00 Storage Depth (ft) : 3.00 Pond Bottom Length (ft) : 2.0 Pond Bottom Width (ft) : 2.0 Pond Side Slopes (ft/ft) : L1= 3.00 L2= 3.00 W1= 3.00 W2= 3.00 Bottom Area (sq-ft) : 4. Area at Riser Crest El (sq-ft) : 400. (acres) : 0.009Volume at Riser Crest (cu-ft): 444. (ac-ft) : 0.010 Area at Max Elevation (sq-ft) : 676. (acres) : 0.016 Vol at Max Elevation (cu-ft): 976. (ac-ft) : 0.022 Hydraulic Conductivity (in/hr) : 0.00 Massmann Regression Used to Estimate Hydralic Gradient Depth to Water Table (ft) : 100.00 Bio-Fouling Potential : Low Maintenance : Average or Better Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 24.00 Common Length (ft) : 0.000 Riser Crest Elevation : 103.00 ft Hydraulic Structure Geometry Number of Devices: 1 ---Device Number 1 --- Device Type : Circular Orifice Control Elevation (ft) : 100.00 Diameter (in) : 1.00 Orientation : Horizontal Elbow : Yes **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 2 Number of Links: 2 ********** Subbasin: Impervious ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 5.167E-02 5-Year 6.790E-02 10-Year 7.625E-02 25-Year 9.386E-02 50-Year 0.107 100-Year 0.133 200-Year 0.137 500-Year 0.142 ********** Subbasin: Pervious ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 3.569E-04 5-Year 3.856E-04 10-Year 3.935E-04 25-Year 8.216E-04 50-Year 1.785E-03 100-Year 2.109E-03 200-Year 3.434E-03 500-Year 5.211E-03 ********** Link: Trench w max overflow Flow Control 91% ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 5.167E-02 5-Year 6.790E-02 10-Year 7.625E-02 25-Year 9.386E-02 50-Year 0.107 100-Year 0.133 200-Year 0.137 500-Year 0.142 ********** Link: Trench w max overflow Flow Control 91% ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 2.478E-05 5-Year 7.796E-03 10-Year 3.512E-02 25-Year 4.523E-02 50-Year 5.881E-02 100-Year 5.981E-02 200-Year 6.554E-02 500-Year 7.325E-02 ********** Link: Trench w max overflow Flow Control 91% ********** Link WSEL Stats WSEL Frequency Data(ft) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) WSEL Peak (ft) ====================================== 1.05-Year 100.982 1.11-Year 101.213 1.25-Year 101.621 2.00-Year 102.478 3.33-Year 103.411 5-Year 104.003 10-Year 104.012 25-Year 104.015 50-Year 104.020 100-Year 104.020 ********** Link: POC ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 3.629E-04 5-Year 6.827E-03 10-Year 2.401E-02 25-Year 3.087E-02 50-Year 3.237E-02 100-Year 3.412E-02 200-Year 3.500E-02 500-Year 3.614E-02 ********** Link: POC ********** Link WSEL Stats WSEL Frequency Data(ft) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) WSEL Peak (ft) ====================================== 1.05-Year 100.001 1.11-Year 100.002 1.25-Year 100.002 2.00-Year 100.002 3.33-Year 100.002 5-Year 100.074 10-Year 100.897 25-Year 101.483 50-Year 101.631 100-Year 101.811 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Converted area pnly 139.311 _____________________________________ Total: 139.311 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Impervious 0.000 Subbasin: Pervious 129.264 Link: Trench w max overflo 51.346 Link: POC 0.000 _____________________________________ Total: 180.610 Total Predevelopment Recharge is Less than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.882 ac-ft/year, Post Developed: 1.143 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 2 ********** Link: Trench w max overflow Flow Control 91% ********** Basic Wet Pond Volume (91% Exceedance): 703. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 1054. cu-ft Time to Infiltrate 91% Treatment Volume, (Hours): 25.10 Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 51.61 Inflow Volume Including PPT-Evap (ac-ft): 51.61 Total Runoff Infiltrated (ac-ft): 51.35, 99.49% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 0.26 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 99.49% ********** Link: POC ********** Basic Wet Pond Volume (91% Exceedance): 605. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 907. cu-ft Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 0.37 Inflow Volume Including PPT-Evap (ac-ft): 0.37 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 0.37 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: Converted area pnly Scenario Postdeveloped Compliance Link: POC *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 5.337E-04 2-Year 3.701E-04 5-Year 5.846E-04 5-Year 7.802E-03 10-Year 5.953E-04 10-Year 3.518E-02 25-Year 5.998E-04 25-Year 4.539E-02 50-Year 6.027E-04 50-Year 5.893E-02 100-Year 6.045E-04 100-Year 6.084E-02 200-Year 6.518E-04 200-Year 6.600E-02 500-Year 7.156E-04 500-Year 7.291E-02 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals **** Flow Duration Performance **** Excursion at Predeveloped 50%Q2 (Must be Less Than or Equal to 0%): 22.6% FAIL Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): 515.6% FAIL Maximum Excursion from Q2 to Q50 (Must be less than 10%): 99999.0% FAIL Percent Excursion from Q2 to Q50 (Must be less than 50%): 100.0% FAIL ------------------------------------------------------------------------------------------------- FLOW DURATION DESIGN CRITERIA: FAIL ------------------------------------------------------------------------------------------------- **** LID Duration Performance **** Excursion at Predeveloped 8%Q2 (Must be Less Than 0%): 35.9% FAIL Maximum Excursion from 8%Q2 to 50%Q2 (Must be Less Than 0%): 29.3% FAIL ------------------------------------------------------------------------------------------------- LID DURATION DESIGN CRITERIA: FAIL ------------------------------------------------------------------------------------------------- 2045 Ramage |O&M. 1 MAINTENANCE MANUAL Retention Requirement A copy of this Manual shall be retained onsite or within reasonable access to the site, and shall be transferred with the property to the new owner. A log of maintenance activity that indicate what actions were taken shall also be kept and be available for inspection. 2045 Ramage |O&M. 1 OPERATIONS, MAINTENANCE AND SOURCE CONTROL MANUAL Table of Contents MAINTENANCE MANUAL 1 INTRODUCTION TO MAINTENANCE AND SOURCE CONTROL MANUALS 2 Figure D.1 – Drainage Facilities Map 3 1. PROJECT DESCRIPTION 4 Table D.1: BMPs and Conveyances for Project 5 2. MAINTENANCE IMPORTANCE AND INTENT 6 3. RESPONSIBLE PARTIES 7 4. FACILITIES REQUIRING MAINTENANCE 7 5. MAINTENANCE INSTRUCTIONS 8 Table D.2: Facilities Requiring Maintenance 9 6. VEGETATION MAINTENANCE 10 7. POLLUTION SOURCE CONTROL MEASURES 11 Storage of Solid Wastes and Yard Wastes 11 Grounds Maintenance 12 ‘Household’ Hazardous Material Use, Storage, and Disposal 14 8. ANNUAL COST OF MAINTENANCE 17 APPENDIX D.A: MAINTENANCE CHECKLISTS 18 2045 Ramage |O&M. 2 Introduction to Maintenance and Source Control Manuals Private facility owners are responsible for ensuring that their stormwater facilities are maintained and continue to function as designed. Routine, scheduled maintenance extends the time between major repairs or replacements. Maintenance may be done in-house, by a maintenance contractor, or a mix of parties. This manual describes what maintenance conditions to check for, and how often to check, for the various facilities that make up the stormwater system on this site. Guidelines for establishing good maintenance and operations procedures are termed Best Management Practices (BMPs). Stormwater management facilities are most effective coupled with good operations procedures. Good operations, such as educating facility users of proper storage and disposal of chemicals and potential pollutants, procedures for spill cleanup, proper use of fertilizers and other vegetation management products, and maintenance of equipment to prevent release of pollutants to the stormwater system, are termed Source Control BMPs. For planning purposes, an initial estimate of annual maintenance and operations costs is presented. Note to Readers: Certain required quotations and text topics are presented in italics. Quotations are set off by quotation marks, required topics are not. It is recommended that a print out of the entire, as- constructed version of the engineering plan set at 11 x 17” or larger be stored with this document so that maintenance personnel have a convenient reference to the location of components, construction details, and installation notes. 2045 Ramage |O&M. 3 Figure D.1 – Drainage Facilities Map 2045 Ramage |O&M. 4 1. Project Description Please refer to the Figure D.1, above, to aid in the project description and show the development layout. This is a selection from the drawing set. The project is intended to construct a new house, detached garage, including exterior grading and drainage improvements for a new drive and entry walk, along with landscaping, and other typical improvements to a residential property. Tree credits are not sought. The entire roof and drive areas will be infiltrated. Soil amendment will be sourced on site or trucked in and tilled into disturbed areas. The following tabulates the existing site data: Addresses: 750 McMinn Rd Parcel Number: 002014003 Site Area Total 552,464 SF (12.68 AC) Building Area (Clearing Limits): 20,320 SF (0.47 AC) Road Length/material: ~40 LF 2045 Ramage |O&M. 5 Describe the stormwater BMPs and conveyance systems, and how these systems are designed to manage the volume, rate, and quality of stormwater runoff from the project. Table D.1: BMPs and Conveyances for Project BMP or Conveyance Volume Management Rate Management Quality Management Soil Amendment Absorbs more precipitation than compacted or organic poor soils. Increases time to first runoff and Decreases overall runoff volume. Increases Biological activity – Caution, also leaches excess nutrients. Infiltration Trench Absorbs precipitation. Increases time to first runoff and Decreases overall runoff volume. Some Filtration. Depends mostly on underlying native soils. PVC pipe/Swale Carries flows to suitable discharge structure. Pipe/Ditch size and slope selected to carry volumes. None. Yard Drain Basins Collects excess surface water. None. Settles out sediment and traps floating debris so discharge is cleaner. 2045 Ramage |O&M. 6 2. Maintenance Importance and Intent Include the following statement in this section: “The importance of maintenance for the proper functioning of stormwater control facilities cannot be over-emphasized. A substantial portion of failures (clogging of filters, resuspension of sediments, loss of storage capacity, etc.) are due to inadequate maintenance. Stormwater BMP maintenance is essential to ensure that BMPs function as intended throughout their full life cycle. The fundamental goals of maintenance activities are to ensure the entire flow regime and treatment train designed for this site continue to fully function. For this site these include: (engineer can delete non applicable BMPs listed below): ▪ Maintain designed stormwater infiltration capacity. ▪ Maintain designed stormwater detention/retention volume. ▪ Maintain ability of storm facility to attenuate flow rates. ▪ Maintain ability to safely convey design stormwater flows. ▪ Maintain ability to treat stormwater runoff quality. ▪ Preserve soil and plant health, as well as stormwater flow contact with plant and soil systems. ▪ Clearly identify systems so they can be protected. ▪ Keep maintenance costs low. ▪ Prevent large-scale or expensive stormwater system failures. ▪ Prevent water quality violations or damage to downstream properties. The intent of this section and manual is to pass on to the responsible party(s) all the information critical to understand the design of the system, risks and considerations for proper use, suggestions for maintenance frequencies, and cost so that realistic budgets can be established.” 2045 Ramage |O&M. 7 3. Responsible Parties This section of the Maintenance and Source Control Manual must identify the party (or parties) responsible for maintenance and operation of all stormwater structures and BMPs requiring maintenance. Owner Self- Maintaining: Yes, unless and until another is charged with this duty. If other, Name of Maintenance Contractor: Address: Phone: Cell: Email: Contact Person: 4. Facilities Requiring Maintenance Provide a detailed list of all stormwater structures and BMPs requiring maintenance. For situations where there are split maintenance responsibilities (e.g., private/public), provide a breakdown of the entity responsible for each structure and BMP. Stormwater Structures BMPs # of places on site Roof Gutters & downspouts 9 4” Stormwater Pipe ~33 LF Tightline ~300 lF Yard Drain (YD)/Inlet 4 Infiltration 1 Dispersion - Soil Amendment 11,708 SF Pervious Paving - Treatment (YD w/Sediment Control) 1 All of the stormwater structures and BMPs requiring maintenance are the responsibility of the landowner. 2045 Ramage |O&M. 8 5. Maintenance Instructions This section shall begin with the following statement, unless otherwise approved by the Jurisdiction: “The parties responsible for maintenance must review and apply the maintenance requirements contained herein. These maintenance instructions outline conditions for determining if maintenance actions are required, as identified through inspection. However, they are not intended to be measures of the facility's required condition at all times between inspections. Exceedance of these conditions at any time between inspections or maintenance activity does not automatically constitute a violation of these standards. However, based upon inspection observations, the inspection and maintenance presented in the checklists shall be adjusted to minimize the length of time that a facility is in a condition that requires a maintenance action. For facilities not owned and maintained by the [jurisdiction], a log of maintenance activity that indicates what actions were taken must be kept on site and be available for inspection by the [jurisdiction].” In addition, include a narrative description of the purpose, function, and maintenance requirements for all stormwater structures and BMPs requiring maintenance. The purpose of the items in the Stormwater Structures list is to collect runoff and excess subsurface drainage and either move it to a treatment BMP so that the acceptable quality is attained or move it to a suitable infiltration area or discharge point. These structures all function by gravity flow, and do not require active processes to function. Maintenance is needed to keep them clean and free-draining. Stormwater Structures on this project are listed in the following table. The purpose of items in the BMP list is to restore the water quality by removing natural sediment, vehicle-deposited particles, liquid drips, and other substances from the runoff before it leaves the site. For this site, all the BMPs are natural functions. They are passive and function by a combination of gravity and microbial action. Maintenance is needed to prevent them from being overtaken by other uses. BMPs on this project are also listed in the following table. 2045 Ramage |O&M. 9 Table D.2: Facilities Requiring Maintenance BMP or Stormwater Structure Purpose Functions by Maintenance Requirement Soil Amendment Reduce runoff quantity and improve quality. Gravity and storage capacity Keep Porosity and organic content high Pervious Pavers & Surfaces Reduce runoff quantity. Gravity and storage capacity Keep clean and Unclogged for porosity Infiltration Trench Reduce runoff quantity. Gravity and storage capacity Keep clean and retain volume Roof Gutters and Downspouts Carries flows to suitable discharge structure. Gravity Keep Clean and free flowing PVC pipe/Swales Carries flows to suitable discharge structure. Gravity Keep Clean and free flowing Yard Drain Basins Collects excess surface water, settles out sediment and traps floating debris. Still water over sump capacity Keep Clean and free flowing Detailed maintenance checklists for all stormwater structures and BMPs requiring maintenance are attached as an Appendix. For up to date guidance over time, please see Appendix V-A of the DOE Stormwater Manual for Western Washington. #5 – Maintenance Checklist for Catch Basins #19 – Maintenance Checklist for Fencing/Shrubbery scree/Other Landscaping #20 – Maintenance Checklist for Grounds (Landscaping) #22 – Maintenance Checklist for Conveyance Systems (Pipes and Ditches) #35 – Maintenance Checklist for Trees The portion of each of these that is not applicable to this site is struck. 2045 Ramage |O&M. 10 6. Vegetation Maintenance A listing and location of plant species and their requirements for maintenance shall be included in this section. This includes newly planted and retained trees claimed as flow reduction credits, as well as vegetation retention and restoration areas. Maintenance requirements must address issues including but not limited to pest and disease management practices, pruning requirements, irrigation requirements, fertilization requirements, etc. Tree Credits: Drainage credits are not sought for landscaping. Vegetation retention and restoration areas: No formal plan for retention of specific trees or vegetation, although clearing limits are smaller than parcel. Landscape Professional Plan to reference: N/A See Architectural set. Standard maintenance checklist #20 for grounds is included for the landscape portion of the disturbed areas. In the event that re-planting is needed for clearing stabilization, we recommend that the following information be collected from the plant nursery for each type of plant. Table D.3: Plant Species List*, Location, & Maintence Requirements (template) Species 1 Number: Locations: Irrigation Needs: Pest & Disease Management: Pruning: Fertilization: 2045 Ramage |O&M. 11 7. Pollution Source Control Measures Pollution source control is the application of pollution prevention practices on a developed site to reduce contamination of stormwater runoff at its source. BMPs and resource management systems are designed to reduce the amount of contaminants used and potentially discharged to the environment. This section of the Maintenance and Source Control Manual shall contain language regarding pollution source controls that are specifically applicable to the site. Storage of Solid Wastes and Yard Wastes Improper storage of recycling, yard waste, and trash can lead not only to water pollution problems, but problems with neighborhood pets and vermin as well. Following the BMPs listed below can help keep the property clean and healthy. Suggested BMPs All recycling and waste containers kept outside should have lids (Figure 3.1). If a lid is damaged, repair or replace it as soon as possible. If a container is supplied by the waste hauler, please call to have the lid repaired or replaced. ▪ Leaking containers should be replaced. If a container is supplied by the hauler, contact the hauler to have damaged containers replaced. ▪ Store containers under cover if possible, or on grassy areas. ▪ Inspect the storage area regularly to pick up loose scraps of material and dispose of them properly. ▪ Tips for reducing waste: Recycle as much as you can. Purchase products which have the least amount of packaging materials. 2045 Ramage |O&M. 12 Grounds Maintenance This section deals with the normal yard maintenance activities as typically performed at homes and basic commercial landscapes. Overwatering, overfertilizing, improper herbicide application, and improper disposal of trimmings and clippings can all contribute to serious water pollution problems. Following the BMPs listed below will help alleviate pollutant runoff. Standard BMPs Follow the manufacturer's directions exactly for mixing and applying herbicides, fungicides, and pesticides, and use them sparingly. Never apply when it is windy or when rain is expected. Never apply over water, within 100 feet of a well-head, or directly adjacent to streams, wetlands, or other water bodies. Triple-rinse empty containers, using the rinsate for mixing your next batch of spray, and then double-bag and dispose of the empty container in your regular garbage. Never dispose of grass clippings or other vegetation in or near storm drains, streams, lakes, or Puget Sound. Suggested BMPs Use natural soil amendments when possible. The excellent soil conditioning properties of the organic matter aid water retention in lighter soils and help to break up and aerate heavier soils, so roots can grow better and less watering is needed. It contains both readily available and long-term nitrogen and other nutrients commonly lacking in Northwest soils. The slow release of nitrogen better matches the needs of plants. Thus, there is much less potential for nitrates to leach into surface or groundwater due both to less “excess nitrogen” and less water use. Better vegetative growth can also reduce erosion and runoff. 2045 Ramage |O&M. 13 ▪ Follow manufacturer's directions when applying fertilizers. More is not better, either for your lawn or for local water bodies. Never apply fertilizers over water or adjacent to ditches, streams, or other water bodies. Remember that organic fertilizers have a slow release of nitrogen, and less potential to pollute then synthetic fertilizers. ▪ Save water and prevent pollution problems by watering your lawn sensibly. Lawns and gardens typically need the equivalent of 1 inch of rainfall per week. You can check on how you're doing by putting a wide mouth jar out where you're sprinkling, and measure the water with a small plastic ruler. Overwatering to the point of runoff can carry polluting nutrients to the nearest water body. ▪ Consider planting a vegetated buffer zone adjacent to streams or other water bodies on your property. Call the County Conservation District for advice and assistance in developing a planting plan ▪ Reduce the need for pesticides and fertilizers on lawns by improving the health of the soil. Aerating, thatching, and topdressing with compost will improve soil health and help wanted grasses compete with weeds and moss. ▪ Make sure all fertilizers and pesticides are stored in a covered location. Rain can wash the labels off of bottles and convert 50 pounds of fertilizer into either a solid lump or a river of nutrients. ▪ Use a mulching mower and mow higher to improve soil/grass health and reduce or eliminate pesticide use. ▪ Compost all yard clippings, or use them as mulch to save water and keep down weeds in your garden. See Composting section for more information. ▪ Practice organic gardening and virtually eliminate the need to use pesticides and fertilizers. Contact the County Cooperative Extension for information and classes on earth- friendly gardening. ▪ Pull weeds instead of spraying and get some healthy exercise, too. If you must spray, use the least toxic formulations that will get the job done. The Master Gardener program listed above can help advise you on which spray to use. 2045 Ramage |O&M. 14 ▪ Work fertilizers into the soil instead of letting them lie on the ground surface exposed to the next rain storm. ▪ Plant native vegetation which is suited to Northwest conditions, they require less water and little to no fertilizers and pesticides. ▪ Contact your local waste disposal company for curbside pickup and recycling of yard waste. ‘Household’ Hazardous Material Use, Storage, and Disposal A variety of hazardous materials are used in commonplace activities . Oil-based paints and stains, paint thinner, gasoline, charcoal starter fluid, cleaners, waxes, pesticides, and wood preservatives are just a few hazardous materials commonly used. When products such as these are dumped on the ground or in a storm drain, they can be washed directly to receiving waters where they can harm fish and wildlife. They can also infiltrate into the ground and contaminate drinking water supplies. The same problem can occur if they are disposed of with your regular garbage; the containers can leak at the landfill and contaminate groundwater. The same type of contamination can also occur if hazardous products are poured down a sink or toilet into a septic system. Don't pour them down the drain if you're on municipal sewers, either. Many compounds can “pass through” the wastewater treatment plant without treatment and contaminate receiving waters, or they can harm the biological process used at the treatment plant, reducing overall treatment efficiency. With such a diversity of hazardous products present, a large potential for serious environmental harm exists if improper methods of storage, usage, and disposal are employed. Using the following BMPs will help keep these materials out of our soils, sediments, and waters. Standard BMPs ▪ Hazardous Materials must be used in accordance with the manufacturer recommendation or guidelines as shown on the label. ▪ Always store hazardous materials in properly labeled containers, never in food or beverage containers which could be misinterpreted by a child as something to eat or drink. ▪ Dispose of hazardous materials and their containers properly. Never dump products labeled as poisonous, corrosive, caustic, flammable, inflammable, 2045 Ramage |O&M. 15 volatile, explosive danger, warning, caution, or dangerous outdoors, in a storm drain, or into sinks, toilets or drains. Call the Hazardous Waste Line at 1-800-287- 6429, for information on disposal methods, collection events, and alternative products. Suggested BMPs ▪ Check hazardous material containers frequently for signs of leakage. If a container is rusty and has the potential of leaking soon, place it in a secondary container before the leak occurs and prevent a cleanup problem. ▪ Hazardous materials should be stored out of the reach of children. ▪ Store hazardous materials containers under cover and off the ground. Keep them out of the weather to avoid rusting, freezing, cracking, labels being washed off, etc. ▪ Keep appropriate spill cleanup materials on hand. Kitty litter is good for many oil-based spills. ▪ Ground cloths and drip pans must be used under any work outdoors which involves hazardous materials such as oil-based paints, stains, rust removers, masonry cleaners, and others bearing label warnings as outlined above. ▪ Latex paints are not a hazardous waste, but are not accepted in liquid form at the landfill. To dispose of, leave uncovered in a protected place until dry, then place in the garbage. If you wish to dry waste paint quickly, mix kitty litter or sawdust in the can to absorb the paint. Once paint is dry, leave the lid off when 2045 Ramage |O&M. 16 you place it in the garbage so your garbage collector can see that it is no longer liquid. ▪ Use less toxic products whenever possible. The Hazardous Waste Line at 1-800- 287-6429 and the Washington Toxics Coalition at (206) 632-1545 have information detailing alternatives to toxic products. ▪ If an activity involving the use of a hazardous material can be moved indoors out of the weather, then do so. Make sure you can provide proper ventilation, however. ▪ Follow manufacturers' directions in the use of all materials. Over- application of yard chemicals, for instance, can result in the • washing of these compounds into receiving water bodies. Never apply pesticides when rain is expected. ▪ When hazardous materials are in use, place the container inside a tub or bucket to minimize spills and store materials above the local base flood elevation (BFE). 2045 Ramage |O&M. 17 8. Annual Cost of Maintenance Provide an estimate of the expected annual cost of maintenance, including identification of the number of catch basins, control structures, linear feet of pipe, etc. Contact the county for additional guidance if needed. Costs to maintence the facilities vary by type, but the budgeting rule of thumb is that annual costs will be 5 to 10% of the facility’s total capital cost if provided by contractors. The first 2 years typically have elevated maintenance costs resulting from nurturing the planting to established conditions. Following that period, routine measures are estimated to have an annual cost of $200 to $600 per acre of facility, with the remaining costs credited toward funding eventual replacement of decayed stormwater features. Routine, scheduled maintenance extends the time between major repairs or replacements. Most facilities have life expectancies of 25 to 50 years, with longer life spans achievable by conscientious maintenance. Table: Estimated Annual Cost of Maintenance Stormwater Structures Unit Price Amount Annual Cost Roof Gutters CREW OF 2@ $150/HR 1 hr Clean sediment $150 Stormwater Pipe Yard Drains & Catch Basins Soil Amendment $75/ CY delivered 5 CY $375 2045 Ramage |18 Appendix D.A: Maintenance Checklists The items that follow are listed for convenience. For up to date guidance over time, please see Appendix V-A of the DOE Stormwater Manual for Western Washington. #5 – Maintenance Checklist for Catch Basins #19 – Maintenance Checklist for Fencing/Shrubbery scree/Other Landscaping #20 – Maintenance Checklist for Grounds (Landscaping) #21 – Maintenance Checklist for Gates #22 – Maintenance Checklist for Conveyance Systems (Pipes and Ditches) #35 – Maintenance Checklist for Trees 2045 Ramage |O&M. 19 2045 Ramage |O&M. 20 2045 Ramage |O&M. 21 2045 Ramage |O&M. 22 2045 Ramage |O&M. 23 2045 Ramage |O&M. 24 002014003 RAMAGE RESIDENCE 552,464 12.68 ~100 5228 ~3600 3384 0 ~4000 4008 ~20,320 146 547 5228 300 200 0 2884 0 0 0 0 0 0 8612 8612 0