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2402 SSPYelm Plat 16418 Middle Road SE, Yelm, WA Parcel No 64303500505, 64303500501 Nw ¼ of the SE ¼, S19, T17 N, R02E, WM, Thurston County, WA Stormwater Site Plan - Drainage Report February 2025 JKA Civil Engineering Inc. 950 Broadway, Suite 305 Tacoma, WA 98402 Ph: (253) 539-1400 E-mail: jkawills@gmail.com Yelm Plat SSP - Drainage Report Prepared for: ABN CONTRACTORS PO BOX 7528 Tacoma, WA 98417 (253) 686-2867 Attn: Adam Norbjerg Adam@abncontractors.com Prepared by: JKA Civil Engineering Inc. 950 Broadway Suite 305 Tacoma, WA 98402 (253) 539-1400 jkawills@gmail.com JKA Project No.: 2402 JKA File No.: P:\2402\Reports\SSP\2402 SSP.doc 2-3-2025 Project Engineer’s Certification: I hereby state that this Drainage Report for Yelm Plat located at 16418 Middle Rd. E. has been prepared by me or under my supervision and meets the minimum standard of care and expertise which is usual and customary in this community for professional engineers. I understand that Thurston County does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me. i Table of Contents Page SECTION 1 - PROPOSED PROJECT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . 1 SECTION 2 - EXISTING CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 SECTION 3 - INFILTRATION RATES/SOILS REPORT . . . . . . . . . . . . . . . . . . . . . . 8 SECTION 4 - WELLS AND SEPTIC SYSTEMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 SECTION 5 - FUEL TANKS . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 9 SECTION 6 - SUB-BASIN DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 SECTION 7 – FLOODPLAIN ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 SECTION 8 - AESTHETIC CONSIDERATIONS FOR FACILITIES. . . . . . . . . . . . . . . 9 SECTION 9 – FACILITY SIZING AND DOWNSTREAM ANALYSIS. . . . . . . . . . . . . . 9 SECTION 10 – UTILITIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 SECTION 11 – CONVENANTS, DEDICATIONS AND EASEMENTS . . . . . . . . . . 10 SECTION 12 – PROPERTY OWNERS ASSOCIATION ARTICLES OF INCORPORATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 SECTION 13 – OTHER PERMITS OR CONDITIONS PLACED ON THE PROJECT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . 10 Appendices I Project Soils Evaluation and Groundwater Monitoring Data II Existing Topography (by Crabtree Surveying LLC.) III Stormwater Calculations and Basin Maps IV Source Control BMPs (c:\2402\Reports\ 2402 SSP.doc) ii Yelm Plat – SSP JKA Civil Engineering Page 1 February 2025 SSP - DRAINAGE REPORT (Note: This report has been prepared in accordance with the Department of Ecology’s 2024 Stormwater Management Manual for Western Washington) SECTION I - PROPOSED PROJECT DESCRIPTION The project proponent is applying for land use permit and site development with driveway approach, stormwater improvements, septic tank effluent pump (STEP) tanks, and public water permitting for the property at 16418 Middle Road SE, Parcel No’s 64303500505, 64303500501. The project will include 23 new single-family residences. Minor improvements are proposed for Middle Road SE public right-of-way (primarily new ADA curb ramps, lane widening, sidewalk, curb and gutter). Onsite improvements include a paved local road and cul-de-sac with cement concrete rolled curb and gutter, sidewalk, closed drainage, stormwater collection/conveyance/ infiltration system and park/open spaces. Existing structures, debris, abandoned vehicles, and equipment will be demolished/removed as part of site development. An existing home and associated garage will remain and become Lot #2 of the plat. The project is not currently served by the City of Yelm for water or sewer. Existing septic system and domestic water well are to be decommissioned as part of this project. Construction will include domestic and fire supply water from a new water main extension; the point of connection will be at Middle Rd SE. All homes shall be served with a water service line and meter. A STEP system will be installed to serve each home. The STEP system forcemain will connect to an existing 6” diameter sewer forcemain located in Middle Road. The goal of this SSP is to obtain City of Yelm site development approvals to allow construction of onsite private site and public improvements as well as public improvements along the Middle Road SE frontage. A tabulation of surfaces for the existing site and proposed development follows: Project Area Tabulation Item On-Site Off-Site Total Total Project Area (ft²) 189,652 5,083 194,735 Ex Roof (SF) 3,788 0 3,788 Ex Driveway (SF) 1,034 0 1,034 Ex Walks, Porches, Conc Pads (SF) 270 0 270 Ex Total Impervious (SF) 5,092 2,000 11,626 Existing Pervious (ft²) 184,560 3,083 203,268 Existing Hard Surface to remain (ft²) 2,043 2,000 3,527 Amount of New Roof area (ft²) 37,700 0 37,700 New sidewalk and misc hard surface (SF) 4,461 652 5,113 Amount of New Driveway (ft²) 12,387 0 12,387 Replaced Driveway (SF) 608 0 608 Amount of New Hard Surface (ft²) 86,195 1,423 87,618 Amount of Replaced Hard Surface (ft²) 608 1,970 2,578 Amount of New + Replaced Hard Surface (ft²) 86,803 3,393 90,196 Amount of New Pollution Generating Hard Surface 44,034 312 44,346 Yelm Plat – SSP JKA Civil Engineering Page 2 February 2025 Amount of Replaced PGHS (ft²) 608 1,970 2,578 Amount of New + Replaced PGHS (ft²) 44,642 1,970 46,612 Hard Surfaces to Pervious Surface (ft²) 0 560 560 Amount of Land Disturbed (ft²) 189,652 5,083 194,735 Native Vegetation to Lawn/Landscaped (acres) 0.60 0 0.60 Native Vegetation to Pasture (acres) 0 0 0 Value of Proposed Improvements ($) TBD TBD TBD Assessed Value of Existing Site Improvements ($) 0 0 0 Amount to be Graded/Filled (cubic yards) 10,000 200 10,200 Proposed Stormwater System – Refer to the basin maps contained in Appendix III of this report and the C Sheets of the JKA Construction Plan The storm drainage mitigation objectives for this residential development are to control runoff of the development area by virtue of: • All new roof areas will be directed to individual downspout infiltration trenches located on each lot. • Rear portion of the existing home and garage roof areas (Lot 2) will have dowspouts tightlined to a downspout infiltration trench to be installed in the rear of the lot. • There will be two separate basin areas. Each basin will accept runoff from individual driveways, front yard landscaping areas, roadway pavement and sidewalk areas. after draining to roadside storm drainage conveyance systems. One basin area will drain to a bioretention area and one basin area will drain to an underground infiltration trench. • Curb/gutter and sidewalk road improvements areas along the frontage of Middle Rd will have drainage collected and conveyed to the onsite bioretention cell. • All areas of the site that will be disturbed, but not covered with roof or other hard surfacing, will have soil amended and/or well-draining topsoil placed to promote infiltration/evaporation of precipitation on individual lots. The project site is very flat and with such well draining soils, the rear yard areas will infiltrate and thus are not counted as contributing to the onsite storm drainage system. Yelm Plat – SSP JKA Civil Engineering Page 3 February 2025 The project is required to address minimum requirements #1 – 9 because the project results in more than 5,000 SF of new plus replaced hard surface area. The project is designed to meet the intent of these requirements as follows: Yelm Plat – SSP JKA Civil Engineering Page 4 February 2025 Minimum Requirement #1 - Preparation of Stormwater Site Plans The project meets requirement #1 by preparation of this drainage report and the ‘Drainage Control Plans’ (aka JKA civil sheets). Minimum Requirement #2 - Construction Stormwater Pollution Prevention The project is designed to meet the intent of Construction SWPPP Elements #1 through #13 as detailed in Volume 1 - Chapter 3 of 2019 DOE Stormwater Management Manual for Western Washington. The 13 elements are summarized below. 1. Preserve Vegetation/Mark Clearing Limits 2. Establish Construction Access 3. Control Flow Rates 4. Install Sediment Controls 5. Stabilize Soils 6. Protect Slopes 7. Protect Drain Inlets 8. Stabilize Channels and Outlets 9. Control Pollutants 10. Control Dewatering 11. Maintain BMPs 12. Manage the Project 13. Protect Low Impact Development (LID) BMP’s These elements are discussed in the SWPPP Report for the project. The SWPPP Report has been prepared as a separate report. Minimum Requirement #3 – Source Control of Pollution Source control BMP’s are structures or an operation that is intended to prevent pollutants from coming into contact with stormwater through physical separation of areas or careful management of activities that are sources of pollutants. There are two types of source control BMPs; structural and operational. Operational BMPs are non-structural practices that prevent or reduce pollutants from entering stormwater. Operational Source Control BMP’s for this residential project include: • Preventive maintenance procedures • Spill prevention and clean up • Good housekeeping practices Structural source control BMPs are physical, structural, or mechanical devices or facilities that are intended to prevent pollutants from entering stormwater. See Appendix IV for detailed description of proposed Source Control BMP’s. Minimum Requirement #4 – Preservation of Natural Drainage Systems and Outfalls This requirement is met by employing onsite BMP’s such as tightlining and directing roof drainage to downspout infiltration trenches and infiltration of road and driveway runoff in Yelm Plat – SSP JKA Civil Engineering Page 5 February 2025 the bioretention cell. Using these BMP’s will maintain natural and existing drainage patterns and discharges from the project site to the maximum extent practicable. This development is a flat site with well-draining soils, thus existing conditions have no drainage systems or outfalls. The developed condition will continue this drainage pattern by infiltration of the entire site (either into the bioretention cell, individual roof downspout infiltration trenches, or simply into the well-draining soil of the landscaping). Minimum Requirement #5 – On-site Stormwater Management 2019 DOE SWMM Minimum Req #5: “Projects shall employ onsite stormwater management BMPs in accordance with the following thresholds, standards, and lists to infiltrate, disperse, and retain stormwater runoff onsite to the extent feasible without causing flooding or erosion impacts. Yelm Plat – SSP JKA Civil Engineering Page 6 February 2025 Yelm Plat – SSP JKA Civil Engineering Page 7 February 2025 This project triggers Min Req’s #1 – 9; thus, the project will use both onsite stormwater management BMPs and onsite infiltration to meet the LID performance standard. Low Impact Development Performance Standard: Stormwater discharges shall match developed discharge durations to pre-developed durations for the range of pre-developed discharge rates from 8 percent of the 2-year peak flow to 50 percent of the 2-year peak flow. Refer to the Standard Flow Control Requirements section in Minimum Requirement #7 for information about the assignment of the pre-developed condition. Project sites that must also meet Minimum Requirement #7 – flow control – must match flow durations between 8 percent of the 2-year flow through the full 50-year flow. Based on the proposed site plan, topography, and soils, the selected BMP’s for meeting Requirement #5 are: soil amendment for the lawn and landscape areas; tightlined roof drains to individual downspout infiltration trenches; infiltration of runoff from sidewalks, driveways, and roadway pavement within a bioretention cell. Minimum Requirement #6 – Runoff Treatment Threshold Discharge Areas (TDA’s) that have a total of 5,000 SF or more of pollution- generating hard surface (PGHS) are required to provide runoff treatment. Stormwater treatment is proposed for this project for the driveways and road pavement. Runoff BMP options for basic treatment were reviewed in the SWMM. The BMP’s considered were: • Manufactured Treatment Devices (such as Old Castle PerkFilter and Contech Stormfilter) • Bioretention swale/cell Bioretention cell was determined to be the most practical BMP to use for one basin and PerkFilter CB for the other basin. The BMP’s selected are appropriate for site conditions and treatment requirements; the ultimate selection is based on cost and ability to integrate the BMP’s into the site. Both water quality BMP’s were modeled using WWHM2012 software. They can treat the water quality storm by filtering a minimum of 91% of the runoff volume. Minimum Requirement #7 – Flow Control Flow control is provided by infiltrating onsite precipitation/runoff within the bioretention cell, within an infiltration trench, and soil amendment (infiltration and transpiration/evaporation). In addition, runoff from roof areas will be directed to individual downspout infiltration trenches located on each lot. The bioretention cell will have 4’ depth of gravel below the 18” depth of BSM in order to provide storage while infiltrating 100% of the runoff volume. Bioretention Cell and infiltration trench calculations can be found in Appendix III. Yelm Plat – SSP JKA Civil Engineering Page 8 February 2025 Minimum Requirement #8 – Wetlands Protection Not applicable. No wetlands exist on or near the site. Minimum Requirement #9 – Operations and Maintenance A stormwater maintenance plan will be prepared as part of the final SSP. It will describe the necessary maintenance required for the collection, conveyance, infiltration, and treatment systems proposed for this project. The Operations and Maintenance Manual will be prepared as a separate document. The bioretention cell is designed to allow maintenance access from the roadway along the east side of the cell. Landscaping of the cell will be per the LID Technical Guidance Manual for Puget Sound and the 2019 DOE SWMM. The PerkFilter CB will be maintained per the manufacturer’s recommendations. SECTION 2 - EXISTING CONDITIONS The 4.35-acre site consists of one unoccupied rectangular 3.44 acre parcel and one irregular shaped 0.91-acre parcel with an existing home and garage. Topography is generally flat with a general elevation of 343’. Vegetation consists mostly of field grasses on the larger rectangular parcel and landscaping on the smaller parcel. The project site is bounded by residential property on all sides. Current access is off Middle Rd SE via a gravel driveway. SECTION 3 - INFILTRATION RATES/SOILS REPORT The USDA Natural Resource Conservation Service (NRCS) Web Soil Survey indicates that the site is underlain by Spanaway gravelly sandy loam (110) and Spanaway stony sandy loam (112) soils. Spanaway soils are derived from volcanic ash over gravelly outwash. These soils have are generally excessively well drained and are included in hydrologic soils group A. On February 16, 2024, Bill Parnell, P.E. visited the site and monitored the excavation of five test pits. See Appendix I for his soils report. He found the soils to be Spanaway series as mapped. Test pits were excavated to a maximum depth of 144” below existing grade. Grain size analysis was used to determine design infiltration rates of 20 in/hr. SECTION 4 - WELLS AND SEPTIC SYSTEMS There is one water service well known to exist on the smaller parcel near the exiting home and will be decommissioned with this development. The project will derive domestic and fire water supply from City of Yelm with a new main extension into the site. Fire hydrants will be placed pursuant to City preferences and homes shall have sprinkler systems installed. Yelm Plat – SSP JKA Civil Engineering Page 9 February 2025 The existing home is served by an onsite septic system; this drainfield and associated septic tank will be decommissioned or removed per Thurston County and Washington State Department of Health requirements. Middle Road contains a City sewer force main line. The new lots and the existing home will have STEP tanks installed and be served by a STEP sewer force main installed in the new plat roadway. SECTION 5 - FUEL TANKS No underground fuel tanks are known to exist. If such tanks are found, they will be abandoned or removed in accordance with current DOE regulations. SECTION 6 - SUB-BASIN DESCRIPTION There is no significant offsite drainage tributary to the project’s developable area. SECTION 7 – FLOOD PLAIN ANALYSIS Review of Thurston County Geodata mapping indicates that the proposed development is outside any areas indicated as 100-year flood zone. SECTION 8 – AESTHETIC CONSIDERATIONS FOR FACILITIES The bioretention cell will be landscaped as appropriate. Low height block walls will be used around a portion of the perimeter of the cell and will be aesthetically pleasing. SECTION 9 – FACILITY SIZING AND DOWNSTREAM ANALYSIS Proposed stormwater BMP's for the single-family development encourages infiltration and evaporation of site precipitation by amending soil and utilizing roof drain infiltration. Primary stormwater BMP’s will consists of treatment and infiltration of PGHS areas. Downstream analysis is not needed due to 100% infiltration onsite. The bioretention cell is sized to treat (water quality) the runoff tributary to it (front yard areas, road pavement from onsite and offsite, and sidewalk areas) through an 18” thick layer of bioretention soil mix (BSM). The cell is sized sufficiently to also infiltrate 100% of the inflow volume to provide adequate flow control. A depth of 4’ of gravel will be placed beneath the 18” BSM layer in order to provide enough storage volume while infiltrating the inflow runoff. Individual roof downspout infiltration trenches will be sized per Vol V - Chapter 4 of the DOE SWMM (page 779). The section on infiltration trenches states that the minimum length per 1,000 sf of roof area can be used for sizing of downspout infiltration trenches based on soil type. For this site, the soil type will be coarse sands and cobbles which equals 20 LF of trench per 1,000 sf of roof area. This is based on a typical trench cross section of 18” depth by 24” width drainrock. For some roofs, the trench width may need to be increased to 36” wide due to available lot width. The length then gets reduced proportionally to 13.33’ LF per 1,000 sf. Yelm Plat – SSP JKA Civil Engineering Page 10 February 2025 SECTION 10 – UTILITIES Stormwater quantity control measures such as roof drain piping, and the infiltration pond will be located away from other utilities as much as possible; however, conflicts may occur during construction. The contractor and owner are advised to inform the project engineer if conditions are encountered which could affect the storm drainage systems, as designed, due to utility conflicts. SECTION 11 – CONVENANTS, DEDICATIONS AND EASEMENTS Onsite drainage facilities including catch basins, piping, bioretention cell, and downspout infiltration trenches will require routine maintenance. The responsibility for maintenance will lie with the property owner and/or their project management team. SECTION 12 – PROPERTY OWNERS ASSOCIATION ARTICLES OF INCORPORATION A Homeowners Association will be established to maintain commonly owned amenities and critical areas/open spaces. SECTION 13 – OTHER PERMITS OR CONDITIONS PLACED ON THE PROJECT Besides a site development permit required for grading, drainage, paving, access, and erosion control improvements, the following approvals may also be required: • City of Yelm - Building permits and SEPA • City of Yelm – Hydrant location and building sprinklering permits • City of Yelm – Sewer Main Extension permit • Puget Sound Energy – Power service • City of Yelm - Water service Appendix I Project Soils Evaluation ABN Contractors Plat Soils Report For Evaluating Site Feasibility of Stormwater Infiltration BMP’s Associated with Road, Roof and Driveway Runoff. Site Address: 16418 Middle Road SE, Yelm WA 98597 PN: 64303500501, 64303500505 Prepared For: ABN Contractors PO Box 7528 Tacoma, WA 98417 Contact: Bo Nordjerg Prepared By: Parnell Engineering, LLC 10623 Hunters Lane S.E. Olympia, WA 98513 Contact: William Parnell, P.E. 360-491-3243 parnelleng@hotmail.com Project Engineer: JKA Civil Engineering 7018 Tacoma Mall Blvd Suite 202. Tacoma, WA 98409 Contact: Will Schuur, P.E. 253-539-01400 jkawills@gmail.com PE PARNELL ENGINEERING, LLC SOIL EVALUATION REPORT FORM 1: GENERAL SITE INFORMATION PROJECT TITLE: ABN Contractors Plat SHEET: 1 OF 1 PE PROJECT NO.:24103 DATE: 2/22/2024 PREPARED BY: William Parnell, P.E. 1. SITE ADDRESS: 16418 Middle Road SE Yelm, WA PN: 64303500501, 64303500505 2. PROJECT DESCRIPTION: Proposed single family residential plat. 3. SITE DESCRIPTION: The rectangular shaped 3.55 acre project site is currently unoccupied. Site topography is generally flat with a general elevation of 343' (Thurston County Geodata). Site vegetation consists of field grasses. The project site is bounded by residential property on all sides. The on -site soils are mapped by the National Resources Conservation Service (NRCS) as a Spanaway gravelly sandy loam (110). Soil test pits confirmed this designation generally profiling a gravelly loam -sandy loam stratum overlying an outwash gravel and sand substratum. Test pits did not reveal a winter water table or any possible indicators. The Spanaway series soils formed out of volcanic ash over gravelly outwash. 4. SUMMARY OF SOILS WORK PERFORMED: A total of five test pits were logged. Test pits were excavated to a maximum depth of 144" below the existing grade. Soils were inspected by entering and visually logging each test pit to a depth of four feet. Soils beyond four feet were inspected by examining trackhoe tailings. Soil samples were taken from all test pits at 84" below the existing grade. A winter water table monitoring port was placed in test pit #3 and #5. Grain size analysis method was used on soils samples taken from test pits #1, #3 and #5 to determine the suitability of the representative soil horizons for stormwater infiltration facilities. An initial saturated hydraulic conductivity (Ksat) was calculated and then reduced by correction factors (CFT) to produce an adjusted design infiltration rate (Ksat design) for facility sizing purposes. Test pit soil log data sheets, grain size analysis data with Ksat calculations are included in this report. 5. ADDITIONAL SOILS WORK RECOMMENDED: Additional soils work should not be necessary. 6. FINDINGS: Soil test pits confirmed the Spanaway soils series as mapped by the NRCS. Test pit profiles revealed no impervious or restrictive horizons and there were no indicators of a winter water table presence. The soil grain size analysis method resulted in adjusted Ksat design values for test pit #1 of 432 in/hr, test pit #3 of 264 in/hr and test pit #5 of 35.7 in/hr. 7. RECOMMENDATIONS: The Spanaway soil series is a somewhat excessively drained soil that formed in volcanic ash over gravelly outwash. Design infiltration rates for all stormwater infiltration facilities located in the C horizon soils should be less than or equal to 20 in/hr as noted in the recommended adjusted Ksat design(F) values provided in the Ksat calculations. Winter water table or any indicators of one were not present. However, a water table monitoring port was placed in test pit #3 and #5 should monitoring be requested by the reviewing agency. Refer to the soil log test pit data sheets included in this report for estimated saturated infiltration rates assigned to each soil horizon., It is the purpose of this report to exclusively evaluate the site for feasibility of stormwater infiltration BMP's associated with road, roof and driveway runoff. This report does not take the place of a detailed soils evaluation and recommendations report by a geologist or geotechnical engineer. I hereby certify that I prepared this report, conducted all the related work and am qualified to do so. I represent my work to be complete and accurate within the bounds of uncertainty inherent to the practice of soils science, to be suitable for its intended use. SIGNED: W DATE: 2// ZZ/Z SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: ABN Contractors Plat SHEET: 1 OF 5 PROJECT NO.: 24103 DATE: 2/16/2024 PREPARED BY: William Parnell, PE SOIL LOG: #1 LOCATION: 50’ south & 50’ east of the northwest property corner. 1. TYPES OF TEST DONE: Soil grain size 2. NRCS SOILS SERIES: Spanaway (110) 3. LAND FORM: Outwash plain 4. DEPOSITION HISTORY: Volcanic ash over gravelly outwash 5. HYDROLOGIC SOIL GROUP: A 6. DEPTH OF SEASONAL HW: Unknown 7. CURRENT WATER DEPTH: Greater than bottom of hole 8. DEPTH TO RESTRICTIVE/IMPERVIOUS HORIZON: Greater than bottom of hole 9. MISCELLANEOUS: Level 10. POTENTIAL FOR: EROSION RUNOFF PONDING Low Low Low 11. SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: No winter water table or possible indicators were present. Grain size analysis method was completed on a soil sample taken at 84” below the existing grade resulting in an adjusted Ksat design = 432 in/hr after reductions were applied. Use a design infiltration rate < 20 in/hr for stormwater facilities where the bottom infiltration surface area is located in the C horizon soils. Refer to the enclosed grain size analysis test results and Ksat design calculations. Soils Strata Description Soil Log #1 Horz Depth Color Texture %CL %ORG CF STR MOT IND CEM ROO <X> FSP A 0”- 20” 10YR2/2 GrCobLm <20 4 <25 1SBK - - - - 2-6 4 Bw 20”- 30” 10YR3/3 VGrCobLmM Sa, some stones <4 - <45 SG - - - - 6-20 15 C1 30”- 72” 10YR4/6 ExGrCobCSa, many stones, some boulders <2 - <85 SG - - - - >20 20 C2 72”-144” 10YR5/2 ExGrCobCSa <2 - <85 SG - - - - >20 20 SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: ABN Contractors Plat SHEET: 2 OF 5 PROJECT NO.: 24103 DATE: 2/16/2024 PREPARED BY: William Parnell, PE SOIL LOG: #2 LOCATION: 40’ south & 175’ west of the northeast property corner. 1. TYPES OF TEST DONE: None 2. NRCS SOILS SERIES: Spanaway (110) 3. LAND FORM: Outwash plain 4. DEPOSITION HISTORY: Volcanic ash over gravelly outwash 5. HYDROLOGIC SOIL GROUP: A 6. DEPTH OF SEASONAL HW: Unknown 7. CURRENT WATER DEPTH: Greater than bottom of hole 8. DEPTH TO RESTRICTIVE/IMPERVIOUS HORIZON: Greater than bottom of hole 9. MISCELLANEOUS: Level 10. POTENTIAL FOR: EROSION RUNOFF PONDING Low Low Low 11. SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: No winter water table or possible indicators were present. Use a design infiltration rate < 20 in/hr for stormwater facilities where the bottom infiltration surface area is located in the C horizon soils. Soils Strata Description Soil Log #2 Horz Depth Color Texture %CL %ORG CF STR MOT IND CEM ROO <X> FSP A 0”- 18” 10YR2/2 GrCobLm <20 4 <30 1SBK - - - - 2-6 4 Bw 18”- 30” 10YR3/3 VGrCobLmM Sa, some stones <4 - <55 SG - - - - 6-20 15 C1 30”- 80” 10YR4/6 ExGrCobM- CSa, many stones, some boulders <2 - <85 SG - - - - >20 20 C2 80”-116” 10YR5/2 ExGrCobCSa, few stones and boulders <2 - <85 SG - - - - >20 20 C3 116”-144” 10YR5/2 ExGrCobCSa, <2 - <85 SG - - - - >20 20 SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: ABN Contractors Plat SHEET: 3 OF 5 PROJECT NO.: 24103 DATE: 2/16/2024 PREPARED BY: William Parnell, PE SOIL LOG: #3 LOCATION: 140’ south & 40’ west of the northeast property corner. 1. TYPES OF TEST DONE: Soil grain size 2. NRCS SOILS SERIES: Spanaway (110) 3. LAND FORM: Outwash plain 4. DEPOSITION HISTORY: Volcanic ash over gravelly outwash 5. HYDROLOGIC SOIL GROUP: A 6. DEPTH OF SEASONAL HW: Unknown 7. CURRENT WATER DEPTH: Greater than bottom of hole 8. DEPTH TO RESTRICTIVE/IMPERVIOUS HORIZON: Greater than bottom of hole 9. MISCELLANEOUS: Level 10. POTENTIAL FOR: EROSION RUNOFF PONDING Low Low Low 11. SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: No winter water table or possible indicators were present. A water table monitoring port was placed and the top of port to the existing ground surface = 13”. Grain size analysis method was completed on a soil sample taken at 84” below the existing grade resulting in an adjusted Ksat design = 264 in/hr after reductions were applied. Use a design infiltration rate < 20 in/hr for stormwater facilities where the bottom infiltration surface area is located in the C horizon soils. Refer to the enclosed grain size analysis test results and Ksat design calculations. Soils Strata Description Soil Log #3 Horz Depth Color Texture %CL %ORG CF STR MOT IND CEM ROO <X> FSP A 0”- 20” 10YR2/2 GrCobLm, some stones <20 4 <30 1SBK - - - - 2-6 4 Bw 20”- 24” 10YR3/3 VGrCobLmM Sa, some stones <4 - <60 SG - - - - 6-20 15 C1 24”- 78” 10YR4/6 ExGrCobCSa, many stones, some boulders <2 - <85 SG - - - - >20 20 C2 78”-110” 10YR5/2 ExGrCobCSa, few stones <2 - <90 SG - - - - >20 20 C3 110”-144” 10YR5/2 ExGrCobCSa, few stones <2 - <90 SG - - - - >20 20 SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: ABN Contractors Plat SHEET: 4 OF 5 PROJECT NO.: 24103 DATE: 2/16/2024 PREPARED BY: William Parnell, PE SOIL LOG: #4 LOCATION: 40’ north & 175’ west of the southeast property corner. 1. TYPES OF TEST DONE: None 2. NRCS SOILS SERIES: Spanaway (110) 3. LAND FORM: Outwash plain 4. DEPOSITION HISTORY: Volcanic ash over gravelly outwash 5. HYDROLOGIC SOIL GROUP: A 6. DEPTH OF SEASONAL HW: Unknown 7. CURRENT WATER DEPTH: Greater than bottom of hole 8. DEPTH TO RESTRICTIVE/IMPERVIOUS HORIZON: Greater than bottom of hole 9. MISCELLANEOUS: Level 10. POTENTIAL FOR: EROSION RUNOFF PONDING Low Low Low 11. SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: No winter water table or possible indicators were present. Use a design infiltration rate < 20 in/hr for stormwater facilities where the bottom infiltration surface area is located in the C horizon soils. Soils Strata Description Soil Log #4 Horz Depth Color Texture %CL %ORG CF STR MOT IND CEM ROO <X> FSP A 0”- 24” 10YR2/2 GrLm <20 4 <20 1SBK - - - - 2-6 4 Bw 24”- 32” 10YR3/3 VGrCobLmM Sa <4 - <40 SG - - - - 6-20 15 C1 32”- 69” 10YR4/6 ExGrCobCSa, few stones and boulders <3 - <85 SG - - - - >20 20 C2 69”-116” 10YR5/2 ExGrCobCSa, few stones <3 - <85 SG - - - - >20 20 C3 116”-144” 10YR5/2 ExGrCobCSa, few stones <3 - <85 SG - - - - >20 20 SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: ABN Contractors Plat SHEET: 5 OF 5 PROJECT NO.: 24103 DATE: 2/16/2024 PREPARED BY: William Parnell, PE SOIL LOG: #5 LOCATION: 50’ north & 50’ east of the southwest property corner. 1. TYPES OF TEST DONE: Soil grain size 2. NRCS SOILS SERIES: Spanaway (110) 3. LAND FORM: Outwash plain 4. DEPOSITION HISTORY: Volcanic ash over gravelly outwash 5. HYDROLOGIC SOIL GROUP: A 6. DEPTH OF SEASONAL HW: Unknown 7. CURRENT WATER DEPTH: Greater than bottom of hole 8. DEPTH TO RESTRICTIVE/IMPERVIOUS HORIZON: Greater than bottom of hole 9. MISCELLANEOUS: Level 10. POTENTIAL FOR: EROSION RUNOFF PONDING Low Low Low 11. SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: No winter water table or possible indicators were present. A water table monitoring port was placed and the top of port to the existing ground surface = 30”. Grain size analysis method was completed on a soil sample taken at 84” below the existing grade resulting in an adjusted Ksat design = 35.7 in/hr after reductions were applied. Use a design infiltration rate < 20 in/hr for stormwater facilities where the bottom infiltration surface area is located in the C horizon soils. Refer to the enclosed grain size analysis test results and Ksat design calculations. Soils Strata Description Soil Log #5 Horz Depth Color Texture %CL %ORG CF STR MOT IND CEM ROO <X> FSP A 0”- 16” 10YR2/2 GrCobLm, some stones <20 4 <25 1SBK - - - - 2-6 4 Bw 16”- 26” 10YR3/3 VGrLmMSa, <4 - <40 SG - - - - 6-20 15 C1 26”- 76” 10YR4/6 ExGrCobC- FSa, some stones and boulders <2 - <75 SG - - - - >20 20 C2 76”-108” 10YR5/2 ExGrCobC- FSa, many stones and boulders <2 - <70 SG - - - - >20 20 C3 108”-144” 10YR5/2 ExGrCobC- FSa, <2 - <70 SG - - - - >20 20 Abbreviations Textural Class (Texture) Structure (STR) Grades of Structure Cobbled - Cob Granular - Gr Strong - 3 Stoney - St Blocky - Blky Moderate - 2 Gravelly - Gr Platy - Pl Weak - 1 Sandy - Sa Massive - Mas Loamy - Lm Single Grained - SG Silty - Si Sub-Angular Blocky - SBK Clayey - Cl Coarse - C Very - V Extremely - Ex Fine - F Medium - M Induration & Cementation (IND) (CEM) Weak - Wk Moderate - Mod Strong - Str Mottles (MOT) 1 Letter Abundance 1st Number Size 2nd Letter Contrast Few - F Fine - 1 Faint - F Common - C Medium - 2 Distinct - D Many - M Coarse - 3 Prominent - P Roots (ROO) 1st Letter Abundance 2nd Letter Size Few - f Fine - f Common - c Medium - m Many - m Coarse - c <X> - Generalized range of infiltration rates from NRCS soil survey (<X>) FSP - Estimated Design Field Saturated Percolation rate based on horizon specific factors and specific test results. 3/4 3/8 4 10 20 40 60 100 200 100 I I 90 j Test Pit #1 at 84" j 80 m i I I, I l Sample 1 f I j• 0 70 I I I L 60 50 j m 40 I I a if I N I I a 30 2 0 20- 10- 0 100 10 1 Sample 1 0.1 0.01 0.001 sand Cobb Groin SO Clay Coarse Medium Fine Ksat Calculations Test pit #1 - sample #1 taken at 84" below the existing grade Soil Gradation Test Results: D10 = 0.85 D60 = 10.9 D90 = 18.9 ffines = 0.0168 log10 (Ksat) = -1.57 + 1.90 (D10) + 0.015 (D60) - 0.013 (D90) - 2.08 (ffines) log10 (Ksat) = -1.57 + 1.90 (0.85) + 0.015 (10.9) - 0.013 (18.9) - 2.08 (0.0168) =-0.0721 Ksat = 0.8469 cm/s Ksat = 0.8469 cm/s x 0.3937 in/cm x 60 s/min x 60 min/hr Ksat = 1200 in/hr Final Design Infiltration Rate Calculation • Ksat design Ksat design = Ksat initial X CFT Ksatinitial = 1200 in/hr CFT (Total Correction Factor - July 2021 SWMM) = CFI x CFt x CFm CFI = 1.0 (three test pits,three soil gradation tests, no soil variability) CFt = 0.4 (grain size method) CFm = 0.9 (siltation & biofouling) CFT= 1.0x0.4x0.9 Ksat design = Ksat initial X CFT Ksatdesign = 1200 in/hr x 1.0 x 0.4 x 0.9 Ksatdesign = 432 In/hr For stormwater facility design purposes, use a Ksat design(F) < 20 in/hr 3/4 3/8 4 10 20 40 60 100 200 100 l i I I I 90 III I Test Pit #3 aV7— 80 I I I i ( I I j • Sample 2 ' E 70 60 I I T 50 I i I I I I I 40 n c I 30 2 a II I I li i 20 I 10 100 10 1 Sample 2 0.1 0.01 0.001 Bond Cobb Grovel Sill C1-1�] Course Medium Fine Ksat Calculations Test pit #3 - sample #2 taken at 84" below the existing grade Soil Gradation Test Results: Di = 0.68 D60 = 9.9 D90 = 19.0 ffines = 0.0279 loglo (Ksat) = -1.57 + 1.90 (D1o) + 0.015 (D60) - 0.013 (D90) - 2.08 (ffines) loglo (Ksat) = -1.57 + 1.90 (0.68) + 0.015 (9.9) - 0.013 (19.0) - 2.08 (0.0279) =-0.2860 Ksat = 0.5176 cm/s Ksat = 0:5176 cm/s x 0.3937 in/cm x 60 s/min x 60 min/hr Ksat = 733 in/hr Final Design Infiltration Rate Calculation : Ksat design Ksat design = Ksat initial X CFT Ksat initial = 733 in/hr CFT (Total Correction Factor - July 2021 SWMM) = CFI x CFt x CFm CFI = 1.0 (three test pits, three soil gradation tests, no soil variability) CFt = 0.4 (grain size method) CFm = 0.9 (siltation & biofouling) CFT = 1.0 x 0.4 x 0.9 Ksat design = Ksat initial X CFT Ksat design = 733 in/hr x 1.0 x 0.4 x 0.9 Ksatdesign = 264 In/hr For stormwater facility design purposes, use a Ksat design(F) < 20 in/hr Ksat Calculations Test pit #5 - sample #3 taken at 84" below the existing grade Soil Gradation Test Results: D10 = 0.31 D60 = 6.9 D90 = 18.0 ffines = 0.0209 log10 (Ksat) = -1.57 + 1.90 (D10) + 0.015 (D60) - 0.013 (D90) - 2.08 (ffines) log10 (Ksat) = -1.57 + 1.90 (0.31) + 0.015 (6.9) - 0.013 (18) - 2.08 (0.0209) = -1.155 Ksat = 0.070 cm/s Ksat = 0.070 cm/s x 0.3937 in/cm x 60 s/min x 60 min/hr Ksat = 99.2 in/hr Final Desian Infiltration Rate Calculation : Ksat design Ksat design = Ksat initial X CFT Ksat initial = 99'.2 in/hr CFT (Total Correction Factor - July 2021 SWMM) = CFI x CFt x CFm CFI = 1.0 (three test pits, three soil gradation tests, no soil variability) CFt = 0.4 (grain size method) CFm = 0.9 (siltation & biofouling) CFT = 1.0 x 0.4 x 0.9 Ksat design = Ksat initial X CFT Ksat design = 99.2 in/hr x 1.0 x 0.4 x 0.9 Ksat design = 35.7 in/hr For stormwater facility design purposes, use a Ksat design(F) < 20 in/hr CL co i X 0 CD C) cli N0 41 CPF cli n CD N 0 cc! 25 0) Q c 14 LL N co 70 N 0 U) ) CL = a) m M :3 .6 a_ z > Appendix II Existing Topography (by Crabtree Surveying LLC) YELM PLAT - CIVIL PLANS = CENTER SECTION 19 A PORTION OF THE NW 1 /4 OF THE SE 1 /4 OF SECTION 19, TOWNSHIP 17 NORTH, RANGE 02 E, W.M., � FOUND 2" BRASS W/PUNCH FOUND 5/8" REBAR W/CAP / CITY OF YELM, THURSTON COUNTY, WASHINGTON PLS 22346 Z m 04auuou 4N DOWN 0.3' 165L5 Jt KAILYVAT KU, HELM, 9u�a/ FOURNIER, ALFRED J & SANDRA G / ® `DOWN 0.3' IN CASE 8-20-2020 /� _ BLOCK t � 8-20-2020 16345 RAILWAY RD SE, YELM, 98597 x LOT 4 RAILWAY RD SEJ - - __ _ _ _ FLUME LANE (VACATED) _ - � N89°34'46'W(SP) S88'41'30"E(C) 1300.64' S88°40'48"E 1355.78'(M) � _ 1.25' LOT 2 5 N89°34'46"W 1355.67'(SP) 00.00' \ \ PN 64300600404WEST_ \ 16320 MIDDLE MRD SE, YEUM�, 9 �� I ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ p ❑ ❑ ❑ ❑ ❑ ❑ ❑❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ BASIS OF BEARINGS: \ WASHINGTON COORDINATE SYSTEM OF 1983, SOUTH ZONE \ \ M NAD83(2011) EPOCH 2O10.00 PER NGS-CORS WASHINGTON STATE REFERENCE NETWORK "WSRN". \� \ ALL DIMENSIONS ARE SHOWN AT GROUND LEVEL, UNLESS OTHERWISE NOTED. REFERENCES/NOTES: BOUNDARY LINE REVISION RECORDING NO. I 1. 3314745 \ LOT 3 RECORDING N0. 43 1. 3922362SARTA NELIIZABETH A o I PLAT RECORDING NO. 16322 MIDDLE RD SE, 1. 3368416 WILLOW GLENN PLAT YELM, 98597 I SHORT PLAT RECORDING NO. 1. 927108 \ o I 2. 927198 3. 3109448 7 1. THIS SURVEY DOES NOT PURPORT TO SHOW ALL EASEMENTS THAT MAY z'> BENEFIT OR BURDEN THE SUBJECT PROPERTY. / w I 2. ONLY IMPROVEMENTS/FEATURES PERTINENT TO THIS SURVEY HAVE BEEN o SHOWN. 3. THIS DRAWING IS NOT TO BE USED FOR DETERMINING THE EXACT z /� LOCATION OF ANY UTILITY LINES. BEFORE STARTING ANY CONSTRUCTION, EACH INDIVIDUAL UTILITY COMPANY MUST BE CONTACTED FOR MOST CURRENT LOCATIONS OF LINES AND/OR CALL 811 FOR UTILITY LOCATE. LEGAL DESCRIPTION: (PER DEED AFN 4794316) PARCEL A: THE NORTH 290 FEET OF THE EAST 500 FEET OF LOT 5 IN BLOCK EX SEPTIC DRAINFIELD TO BE ABANDONED 35 OF MCKENNA IRRIGATED TRACTS, AS RECORDED IN VOLUME 9 OF / PLATS, PAGE 43; TOGETHER WITH THE SOUTH HALF OF VACATED STREET ADJOINING SAID PROPERTY ON THE NORTH. IN THURSTON COUNTY, WASHINGTON LOT 4 0 0 N CD m PN 64300600406 EX WELL TO BE DECOMMISSIONED PARCEL B: LASTANT, JAMES J LOT 2 OF SHORT SUBDIVISION NO. SS-97-8187-YL, AS RECORDED XX 16326 MIDDLE RD SEPTEMBER 1, 1997 UNDER AUDITOR'S FILE NO.S 3109447 AND / SE, YELM, 98597 I 00 M 3109448 IN THURSTON COUNTY, WASHINGTON I I VERTICAL DATUM: PER NGS-CORS WASHINGTON STATE REFERENCE NETWORK "WSRN" AND APPLIED GEOID 12B CONTOUR INTERVAL = 1' / \ PLAT OF MCKENNA IRRIGATED TRACTS \�-®24, V.1 IP..112177 LOT 4 BLOCK 35 I I PN 64300600406 PLAT OF MCKENNA IRRIGATED TRACTS � LOT 5 ^ I I \ FOUND 1/2' REBAR W/CAP 347' BLOCK 35 Q� FOUND 1/2" REBAR W/CAP, ��--------- I I S PLS 27134 HANSEN RAVEL DRIVEWAY PLS 27134 HANSEN I GRAVEL x—xx—xxx—x DOWN o.2' l `\ 8-20-2020 Q �1 PN 64303500505 X / � I I N88°41'30"W 8-20-2020 I" COVER SHED , 41 44.00' _ ±134' CONTAINER COVER 0.8' 1 SHED \ 3.7, PN 64303500503 �� - ❑ � I � G I GRAVEL I FOUND 1/2" REBAR LEGEND (EXISTING) FOUND MONUMENT AS NOTED O FOUND 5/8" REBAR W/ CAP • SET 1/2" REBAR W/STEEL CAP (C) CALCULATED (M) MEASURED (SP) SHORT PLAT AFN 3109448 ® SEPTIC TANK LID ❑SSB SEWER BOX UTILITY POLE STREET SIGN ❑UCAB UTILITY CABINET GUY POLE p u MAIL BOX ❑PB POWER BOX ❑P POWER METER P POWER RISER oP POWER PANEL Da SEWER VALVE D4 WATER VALVE 83 WATER METER -6- HYDRANT (FH) Q SANITARY SEWER MANHOLE (SSMH) ❑ STORM DRAIN CATCH BASIN SS - SANITARY SEWER LINE STORM DRAINAGE LINE - - W WATER LINE EDGE OF PAVEMENT - ROAD CENTERLINE RIGHT-OF-WAY/PROPERTY LINE (R/W T) x x x WIRE FENCE ❑—❑- WOOD BOARD FENCE ao FENCE - GATE \ \ JOHNSON, LEE THOMAS 1 _ - - - - 1 o MOWE1364MMIDDLE ST SE, YELM, 98597 � � I � � � GRAVEL � �� I I W/ PLASTIC CAP N58°25'00"E 0.74' PLS ` ` I I CARPORT 271J4, HANSEN UP 11, MEASURED BAS SE TIC - - / 2-1-2024 I�Fj-� CONC. FOUNDATION \ -- GRAVEL I I Z cn w CONC/ j SHORT AT AFN:4877943 LOT 1 ` � RET61�+N'G '� BPRN �41 PN 84070000500 � � 'a � ,,.; w � I Z `�"� / o J O) t/7 cn Z LOT 1 I WALL Oco o o z I o o �' I o o�' \ cl' �A. O LOT5 �oc� aao w I o�Q C3E, �S•Sty 6�\I L RAILROAD TIE l PN 84070000500 o o Q Q o F-1 � o �' Q � � C)Lo t1p\�S of(� 00 FOUND 1/2" REBAR W/CAP �� ^ O�sF SHED KAYE, AARON M I J a r Q I ^ o Y Q� o ¢ rn o Q m F 6> �" (� OG. PLS 27134 HANSEN �� - �6' �, I 16404 CASCADIAN AVE SLQ*EW, 98597 z a `' o o rn o —z I of o - c� ��\8 '/" \ DOWN 0.1, C \ "� o_� C.0 oowN� o��r °0�cn c s�6�\ Os \� 8-20-2020 �� / \ CONC. PAD % BFF= 27' ' , J ¢ Z Y � a a o o Cj SAS„ q1 ) Q ❑— J6Z CONC. FOUND 1/2" REBAR W/PLASTIC CAP STEPS SEPTIC P�63` 01 M / �x PLS 27134, HANSEN \ SHORT PLAT AFN:4877943 "� 2-1-2024 / TO REMAIN \ / _ / � / \ \ `r A2• ,30' ACdESS EASEMEV PER SHORT PLAT AFN 310 \ i LOT 2 / I BFF=344.92' � CONC. o 4s ¢ LOT 4 f' G \� \ I BFF-349.26' o� \i^� �' PN 84070000400 HOUSE c 1 I �. HASS, RICHARD K \ TO REMAIN �� O 16402 CASCADIAN \ �19. I \ AVE SE jL$ \ 98 � � � \ \ � � �3�8, �.� � � CONC. STEP O� 30 X71 PRIVATE SHARED 346\ I I PN 84070000400 ACCESS & UTILITY EASEMENT �� - �� TO BE RELINQUISHED UPON Off'` A o��\� 348 i LOT 3 T \ \ �� 7 �� ✓ PN 84070000300 \ EXTENSION OF CITY STREET PEREZ CAMERON C O \ FOR FUTURE DEVELOPMENT. �� oo \ \ P \ \� CONC. / ��/ � � 16340 CASCADIAN AVE \ L qg / \ ✓ \�� /� » SE, YELM, 98597 \ FOUND 2" BRASS W/PUNCH iy 8-20-2020 c CAB `� \ \\� O / LOT 3 GRAVEL C) \ LOT 2 PN 84070000300 \ 3¢j✓ a� PN 84070000200 O'CONNELL, ERICA & STEVEN 16338 CASCADIAN AVE SE, LOT 1 YELM, %oV72PN DRAGT OFAM�LY10 C \ PN 84070000200 \ EX. -D PVC FACE CURB \ 16A336 CASCADIAN WATER MAIN VE SE, YELM, ` \ 98597 / EX. 6" SS \ \\ \ \ LOT 1 \ FORCEMAIN FACE CURB �,I \ \ \ \ PN 84070000100 / / FOUND 1/2" REBAR W/PLASTIC CAP FACE CURB \ CAP ILLEGIBLE 12-21-2023 10' ADDITIONAL R/W DEDICATED \ PER SHORT PLAT AFN 3109448 / PLAT OF WILLOW GLENN In a oo m co C)ca CD cD N GRAPHIC SCALE 30 0 15 30 60 ( IN FEET ) /4 s / FOUND 3" BRASS W/PUNCH PLS 27192 SKILLINGS CONNOLLY 8-20-2020 PROJECT SURVEYOR: -EAST 1/4 CORNER — PER SP LOT 64 PN 84070006400 PUTRA, ROY C 9831 GREENLEAF LOOP SE, YELM, 98597 PLAT OF WILLOW GLENN DIV 2 LOT 65 PN 84070006500 PRATT, MIKE & STEPHANIE 9837 GREENLEAF LOOP SE, YELM, 98597 LOT 66 PN 84070006600 ALVAREZ, WILLIAM SANTIAGO 9843 GREENLEAF LOOP SE, YELM, 98597 LOT 67 PN 84070006700 FERIDO, MARK & SHEYRAL 9849 GREENLEAF LOOP SE, YELM, 98597 LOT 68 PN 84070006800 SWEENEY, CHRISTOPHER 9855 GREENLEAF LOOP SE, YELM, 98597 THE BOUNDARY AND TOPOGRAPHIC SURVEY WAS PERFORMED BY CRABTREE SURVEYING, LLC. JKA WAS PROVIDED CAD FILES OF THE TOPOGRAPHIC SURVEY IN JULY,K 2024. JAMES CRABTREE'S CONTACT INFORMATION IS: 7328 104TH ST E PUYALLUP, WA 98373 253-845-0048 CRABTREESURVEYING.COM Cn z O 0 L.LJ Q G U 0 W co Lil 0) �- Q z X Z 0a ¢ Um::E 00 O d- � � co w z O N ~ � C) cry z J CID z L�i.l zm C� 3 (Yj J � 0 0 U (n (n U 4 tam .i, 04 NN ?14, N ? 0 0 O U 0 z �E In Lu r7 3 W In o �Y 0 Z a_ Li Lu J In 0 > II / M III > N U III / O in � III T or) Q III III O 111 ' ° O m E nl o III / L U �\ In o MiQ7 III JKA PROJECT NO. 2402 DRA WING NAME 2402—C3.0.DWG C3.0 N O � 0 Z 0--\CIVI�JO PROJ\ZGOZ\OWG\r�Of5tl ECr5\CIVIC\240Z-05.O.OWG Appendix III Stormwater Calculations and Basin Maps N GRAPHIC SCALE 0 30 60 ( IN FEET ) DEVELOPED CONDITION MAP LEGEND j - - - - - - I AREA TO BE DISTRUBED - - - - - - - (194,531 SF/4.47 AC) IMPERVIOUS LOT AREA ROOFS, WALKWAYS, DRIVEWAYS (54,700 SF/1.26 AC) ASPHALT CONCRETE PAVEMENT INCLUDING CURB & GUTTER (33,929 SF/0.78 AC) CEMENT CONCRETE SIDEWALK (5,113 SF/0.12 AC) LANDSCAPE AREA W W W W W (100,789/2.31 AC) 0\0000 PR0J\240eVCP09f5\BA5IN MAP5\e4OZ - 0Wa0ff0VWG GRAPHIC SCALE 60 0 30 60 120 -- j( IN FEET) I I I � I I ---1-------- - y �� O �s F \ � j G I R 347 BASIN AREA TO BIORET. SYSTEM WEST: LEGEND ROADWAY PVMNT AREA TRIBUTARY TO BIORETENTION = 22,600 SF (0.519 AC) DRIVEWAY AREA = 7,271 SF (0.167 AC) SIDEWALK AREA = 2,570 SF (0.059 AC) LANDSCAPE AREA = 20,279 SF (MODELED AS PASTURE) (0.466 AC) BASIN MAP WEST (BIORETENTION) 0 \UVIL30 PROJ\2 OZ\REPORTS\BASIN W5\2402 BA5I1V.0W0 GRAPHIC SCALE - - -- 60 0 30 60 120 � i �- N ( IN FEET) � I - / I -- j i f -----_--- I 346 BASIN AREA TO INFILTRATION SYSTEM EAST: .347 LEGEND ROADWAY PVMNT AREA TRIBUTARY TO INFIL. TRENCH = 14,036 SF (0.322 AC) DRIVEWAY AREA = 6,071 SF 0.139 AC \ �4 f SIDEWALK AREA = 2,543 SF (0.058 AC) • / 9 \ 347� / \ LANDSCAPE AREA = 15,834 SF (MODELED AS PASTURE) (0.363 AC) \ \ ROOF AREA = 702 SF (0.016 AC) (NORTH PORTION OF EXISTING HOME'S ROOF) \ BASIN MAP EAST (TRENCH) 0 \UVI�30 PROJ\2 OZ\REPORTS\BASIN W5\2402 BA511V.0W0 WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: CONCEPTUAL-BIORET-WEST Site Name: Norbjerg Yelm Plat Site Address: Middle Rd SE City : Yelm Report Date: 10/19/2024 Gage : Lake Lawrence Data Start : 1955/10/01 Data End : 2008/09/30 Precip Scale: 0.86 Version Date: 2024/01/31 Version : 4.2.19 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ MITIGATED LAND USE Name : Developed Bypass: No GroundWater: No Pervious Land Use acre A B, Pasture, Flat .466 Pervious Total 0.466 Impervious Land Use acre ROADS FLAT 0.519 DRIVEWAYS FLAT 0.167 SIDEWALKS FLAT 0.059 Impervious Total 0.745 Basin Total 1.211 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater Surface retention 1 Surface retention 1 ___________________________________________________________________ Name : Bioretention 1 Bottom Length: 28.00 ft. Bottom Width: 28.00 ft. Material thickness of first layer: 0.25 Material type for first layer: ASTM 100 Material thickness of second layer: 1.5 Material type for second layer: SMMWW 12 in/hr Material thickness of third layer: 4 Material type for third layer: GRAVEL Infiltration On Infiltration rate: 20 Infiltration safety factor: 1 Bioretention Cell - West Basin landscape area with amended soil from front of lots roadway pavement from onsite and offsite bioretention cell with bottom area = 28'x28'=784 sf Design bottom area of irregular shaped bioret=789 sf top layer is 3" of mulch 2nd layer is the treatment layer of 18" depth of BSM bottom layer is 4' depth of gravel for storage in the voids 20 in/hr design rate of the native soil below the gravel Wetted surface area On Total Volume Infiltrated (ac-ft.): 134.373 Total Volume Through Riser (ac-ft.): 0.006 Total Volume Through Facility (ac-ft.): 134.379 Percent Infiltrated: 100 Total Precip Applied to Facility: 6.107 Total Evap From Facility: 2.65 Underdrain not used Discharge Structure Riser Height: 0.52 ft. Riser Diameter: 12 in. Element Flows To: Outlet 1 Outlet 2 ___________________________________________________________________ Bioretention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.1257 0.0000 0.0000 0.0000 0.0799 0.1236 0.0007 0.0000 0.0000 0.1598 0.1215 0.0015 0.0000 0.0000 0.2397 0.1193 0.0023 0.0000 0.0000 0.3196 0.1172 0.0031 0.0000 0.0002 0.3995 0.1151 0.0039 0.0000 0.0004 0.4793 0.1131 0.0047 0.0000 0.0010 0.5592 0.1110 0.0056 0.0000 0.0012 0.6391 0.1090 0.0065 0.0000 0.0020 0.7190 0.1070 0.0074 0.0000 0.0034 0.7989 0.1050 0.0084 0.0000 0.0035 0.8788 0.1030 0.0094 0.0000 0.0055 0.9587 0.1011 0.0105 0.0000 0.0075 1.0386 0.0991 0.0116 0.0000 0.0085 1.1185 0.0972 0.0127 0.0000 0.0121 1.1984 0.0953 0.0138 0.0000 0.0141 1.2782 0.0934 0.0151 0.0000 0.0171 1.3581 0.0916 0.0163 0.0000 0.0228 1.4380 0.0897 0.0176 0.0000 0.0242 1.5179 0.0879 0.0189 0.0000 0.0306 1.5978 0.0861 0.0203 0.0000 0.0374 1.6777 0.0843 0.0217 0.0000 0.0403 1.7576 0.0825 0.0230 0.0000 0.0504 1.8375 0.0808 0.0244 0.0000 0.0567 1.9174 0.0790 0.0258 0.0000 0.0641 1.9973 0.0773 0.0273 0.0000 0.0782 2.0771 0.0756 0.0288 0.0000 0.0825 2.1570 0.0740 0.0303 0.0000 0.0969 2.2369 0.0723 0.0319 0.0000 0.1130 2.3168 0.0707 0.0335 0.0000 0.1171 2.3967 0.0690 0.0352 0.0000 0.1221 2.4766 0.0674 0.0369 0.0000 0.1441 2.5565 0.0659 0.0386 0.0000 0.1630 2.6364 0.0643 0.0405 0.0000 0.1674 2.7163 0.0628 0.0423 0.0000 0.1717 2.7962 0.0612 0.0442 0.0000 0.1762 2.8760 0.0597 0.0462 0.0000 0.1807 2.9559 0.0582 0.0482 0.0000 0.1852 3.0358 0.0568 0.0502 0.0000 0.1899 3.1157 0.0553 0.0523 0.0000 0.1945 100% volume infiltation riser is set at 6.25" Bioretention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 3.1956 0.0539 0.0545 0.0000 0.1992 3.2755 0.0525 0.0567 0.0000 0.2040 3.3554 0.0511 0.0590 0.0000 0.2089 3.4353 0.0497 0.0613 0.0000 0.2138 3.5152 0.0484 0.0637 0.0000 0.2187 3.5951 0.0470 0.0661 0.0000 0.2237 3.6749 0.0457 0.0686 0.0000 0.2288 3.7548 0.0444 0.0711 0.0000 0.2339 3.8347 0.0431 0.0737 0.0000 0.2391 3.9146 0.0419 0.0763 0.0000 0.3698 3.9945 0.0406 0.0791 0.0000 0.3778 4.0744 0.0394 0.0818 0.0000 0.3859 4.1543 0.0382 0.0846 0.0000 0.3941 4.2342 0.0370 0.0875 0.0000 0.4023 4.3141 0.0358 0.0905 0.0000 0.4107 4.3940 0.0347 0.0935 0.0000 0.4191 4.4738 0.0335 0.0965 0.0000 0.4276 4.5537 0.0324 0.0997 0.0000 0.4363 4.6336 0.0313 0.1029 0.0000 0.4450 4.7135 0.0303 0.1061 0.0000 0.4537 4.7934 0.0292 0.1094 0.0000 0.4626 4.8733 0.0282 0.1128 0.0000 0.4716 4.9532 0.0272 0.1163 0.0000 0.4806 5.0331 0.0262 0.1198 0.0000 0.4897 5.1130 0.0252 0.1234 0.0000 0.4990 5.1929 0.0242 0.1270 0.0000 0.5082 5.2727 0.0233 0.1307 0.0000 0.5176 5.3526 0.0223 0.1345 0.0000 0.5271 5.4325 0.0214 0.1384 0.0000 0.5367 5.5124 0.0205 0.1423 0.0000 0.5463 5.5923 0.0197 0.1463 0.0000 0.5560 5.6722 0.0188 0.1503 0.0000 0.5658 5.7500 0.0180 0.1544 0.0000 0.5755 Surface retention 1 Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) To Amended(cfs) Wetted Surface 5.7500 0.1257 0.1544 0.0000 0.0664 0.0440 5.8299 0.1279 0.1645 0.0000 0.0664 0.0883 5.9098 0.1301 0.1748 0.0000 0.0693 0.1331 5.9897 0.1323 0.1853 0.0000 0.0722 0.1782 6.0696 0.1345 0.1959 0.0000 0.0751 0.2237 6.1495 0.1368 0.2068 0.0000 0.0780 0.2696 6.2293 0.1391 0.2178 0.0000 0.0809 0.3158 6.3092 0.1414 0.2290 0.0824 0.0838 0.3624 6.3891 0.1437 0.2404 0.4320 0.0867 0.4094 6.4690 0.1460 0.2520 0.9015 0.0896 0.4568 6.5489 0.1484 0.2637 1.3901 0.0925 0.5046 6.6288 0.1507 0.2757 1.8011 0.0954 0.5527 6.7087 0.1531 0.2878 2.0739 0.0983 0.6013 6.7886 0.1555 0.3001 2.2681 0.1012 0.6501 6.8685 0.1580 0.3126 2.4366 0.1041 0.6994 6.9484 0.1604 0.3254 2.5941 0.1070 0.7491 7.0282 0.1629 0.3383 2.7426 0.1099 0.7991 7.1081 0.1653 0.3514 2.8835 0.1128 0.8495 7.1880 0.1678 0.3647 3.0178 0.1157 0.9003 7.2679 0.1704 0.3782 3.1463 0.1186 0.9016 7.2700 0.1704 0.3786 3.2699 0.1187 0.0000 ___________________________________________________________________ Name : Surface retention 1 Element Flows To: Outlet 1 Outlet 2 Bioretention 1 ___________________________________________________________________ ___________________________________________________________________ Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2024; All Rights Reserved. WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: CONCEPTUAL-EAST-TRENCH Site Name: Norbjerg Yelm Plat Site Address: Middle Rd SE City : Yelm Report Date: 10/19/2024 Gage : Lake Lawrence Data Start : 1955/10/01 Data End : 2008/09/30 Precip Scale: 0.86 Version Date: 2024/01/31 Version : 4.2.19 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ MITIGATED LAND USE Name : Developed-EAST Bypass: No GroundWater: No Pervious Land Use acre A B, Pasture, Flat .363 Pervious Total 0.363 Impervious Land Use acre ROADS FLAT 0.322 ROOF TOPS FLAT 0.016 DRIVEWAYS FLAT 0.139 SIDEWALKS FLAT 0.058 Impervious Total 0.535 Basin Total 0.898 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater Gravel Trench Bed 1 Gravel Trench Bed 1 ___________________________________________________________________ Name : Gravel Trench Bed 1 Bottom Length: 82.00 ft. Bottom Width: 5.50 ft. Trench bottom slope 1: 0 To 1 Trench Left side slope 0: 0 To 1 Trench right side slope 2: 0 To 1 Material thickness of first layer: 4 Pour Space of material for first layer: 0.4 Material thickness of second layer: 0 Pour Space of material for second layer: 0 Material thickness of third layer: 0 INFILTRATION TRENCH EAST Landscaping with amended soil (front yards of Lots 1 - 10) paving from south side of Access Rd and south side of cul-de-sac road. roof area of north portion of existing home on Lot 2 driveways from Lots 1 - 10 sidewalk area along Lots 1 - 10 proposed infiltration trench 82' L x 5.5' W drainrock depth = 4' Pour Space of material for third layer: 0 Infiltration On Infiltration rate: 20 Infiltration safety factor: 1 Wetted surface area On Total Volume Infiltrated (ac-ft.): 93.609 Total Volume Through Riser (ac-ft.): 0.003 Total Volume Through Facility (ac-ft.): 93.612 Percent Infiltrated: 100 Total Precip Applied to Facility: 0 Total Evap From Facility: 0 Discharge Structure Riser Height: 4 ft. Riser Diameter: 8 in. Element Flows To: Outlet 1 Outlet 2 ___________________________________________________________________ Gravel Trench Bed Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.010 0.000 0.000 0.000 0.0556 0.010 0.000 0.000 0.208 0.5000 0.010 0.002 0.000 0.208 1.0000 0.010 0.004 0.000 0.208 1.5000 0.010 0.006 0.000 0.208 2.0000 0.010 0.008 0.000 0.208 2.5000 0.010 0.010 0.000 0.208 3.0000 0.010 0.012 0.000 0.208 3.5000 0.010 0.014 0.000 0.208 4.0000 0.010 0.016 0.000 0.208 4.0556 0.010 0.017 0.092 0.208 4.1111 0.010 0.017 0.255 0.208 4.1667 0.010 0.018 0.441 0.208 4.2222 0.010 0.018 0.610 0.208 4.5000 0.010 0.021 0.989 0.208 5.0000 0.010 0.026 1.399 0.208 ___________________________________________________________________ ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area:0.363 Total Impervious Area:0.535 ___________________________________________________________________ (ac-ft) (ac-ft) Credit Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2024; All Rights Reserved. 20in/hr design rate 100% volume infiltrated WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: prelim-WQ-EAST Site Name: Norbjerg Yelm Plat Site Address: Middle Rd SE City : Yelm Report Date: 10/19/2024 Gage : Lake Lawrence Data Start : 1955/10/01 Data End : 2008/09/30 Precip Scale: 0.86 Version Date: 2024/01/31 Version : 4.2.19 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ MITIGATED LAND USE Name : Developed-EAST Bypass: No GroundWater: No Pervious Land Use acre A B, Pasture, Flat .363 Pervious Total 0.363 Impervious Land Use acre ROADS FLAT 0.322 ROOF TOPS FLAT 0.016 DRIVEWAYS FLAT 0.139 SIDEWALKS FLAT 0.058 Impervious Total 0.535 Basin Total 0.898 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.22495 5 year 0.308755 10 year 0.370721 25 year 0.45671 50 year 0.52657 100 year 0.601589 ___________________________________________________________________ ___________________________________________________________________ PerkFilter Sizing for East Basin Landscaping with amended soil (front yards of Lots 1 - 10) paving from south side of Access Rd and south side of cul-de-sac road. roof area of north portion of existing home on Lot 2 driveways from Lots 1 - 10 sidewalk area along Lots 1 - 10 100yr Q to PerkFilter Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0.0777 acre-feet On-line facility target flow: 0.0927 cfs. Adjusted for 15 min: 0.0927 cfs. Off-line facility target flow: 0.0525 cfs. Adjusted for 15 min: 0.0525 cfs. ___________________________________________________________________ Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2024; All Rights Reserved. WQ treatment flow rate to PerkFilter = 0.053 cfs Appendix IV Source Control BMP’s Automobile Washing Most residents wash their cars in the driveway or on the street. Washwaters typically flow to a storm drain or ditch, which discharges stormwater directly to the nearest river, stream, lake, or Puget Sound. Soaps and detergents, even the biodegradable ones, can have immediate and long-term effects on critters living in water bodies. The grime washed off the car also contains a variety of pollutants that can harm fish and wildlife. Suggested BMPs Away from Home (preferred option): • Consider not washing your car at home. Take it to a commercial car wash that has a recycle system and discharges wastewater to the sanitary sewer for treatment. At Home: • Wash your car directly over your lawn or make sure the washwater drains to a vegetated area. This allows the water and soap to soak into the ground instead of running off into a local water body. • Ideally, no soaps or detergents should be used, but if you do use one, select one without phosphates. • Commercial products are available that allow you to clean a vehicle without water. These were developed for areas where water is scarce, so a water saving benefit is realized, as well as reduced pollution. • Use a hose nozzle with a shut-off valve to save water. • Do not wash your car if rain is expected. Rain events will rapidly wash and chemicals and cleaning products from your property into the stormwater system (and to downstream waters). • Pour the bucket of soapy, dirty washwater down your sink. This way the water doesn’t pollute surface water. Instead, it’s treated at the wastewater treatment plant. Automobile Maintenance Many of us are “weekend mechanics”. We enjoy the cost savings of changing our own oil and antifreeze, topping off the battery with water, and generally making our car perform its best. There is a lot of potential for stormwater pollution associated with these activities; however, the following BMPs will help you minimize pollution while servicing your car. Required BMPs • Recycle all oils, antifreeze, solvents, and batteries. Many local car parts dealers and gas stations accept used oil. The Household Hazardous W aste facilities at the Tacoma Landfill or LRI Landfill accept oil, oil filters, antifreeze, and solvents. Thurston County and Tacoma also hold Household Hazardous Waste turn-in days that will accept car wastes including old batteries. Old batteries can actually be worth money. Search for local battery recycling businesses to find out if any offer to buy used batteries. Use the numbers listed in Chapter 7 for more information. • Never dump new or used automotive fluids or solvents on the ground, in a storm drain or street gutter, or in a water body. Eventually, it will make its way to local surface waters or groundwater, including the water we drink. • Do not mix wastes. The chlorinated solvents in some carburetor cleaners can contaminate a huge tank of used oil, rendering it unsuitable for recycling. Always keep your wastes in separate containers which are properly labeled and store them out of the weather. Suggested BMPs • Fix all leaks, to keep the leaky material off streets and out of surface water. • To dispose of oil filters, punch a hole in the top and let drain for 24 hours. This is where a large funnel in the top of your oil storage container will come in handy. After draining, wrap in 2 layers of plastic and dispose of in your regular garbage or recycle by taking it to the Tacoma Landfill or LRI Landfill Household Hazardous Waste facility for Tacoma residents and non- residents. Call the Hazardous Waste line at 1-800-287-6429 for up-to-date information on the appropriate disposal of consumer products. • Use care in draining and collecting antifreeze to prevent accidental spills. Spilled antifreeze can be deadly to cats and dogs that ingest it. • Perform your service activities on concrete or asphalt or over a plastic tarpaulin to make spill cleanup easier. Keep a bag of kitty litter on hand to absorb spills. If there is a spill, sprinkle a good layer on the spill, let it absorb for a little while and then sweep it up. Place the contaminated litter in a plastic bag, tie it up, and dispose of it in your regular garbage. Take care not to leave kitty litter out in the rain; it will form sticky goo that is hard to clean up. • If you are doing body work outside, be sure to use a tarpaulin to catch material resulting from grinding, sanding, and painting. Dispose of this waste by double bagging in plastic and placing in your garbage. Storage of Solid Wastes and Yard Wastes Improper storage of recycling, yard waste, and trash at residences 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 your property a clean and healthy place to live. Suggested BMPs All recycling and waste containers kept outside should have lids (Figure 3.1). If your lid is damaged, you should repair or replace it as soon as possible. If your container is supplied by your hauler, please call to have the lid repaired or replaced. Find your hauler’s contact information at: <www.piercecountywa.org/recycle>. • Leaking containers should be replaced. If your container is supplied by your 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: o Recycle as much as you can. Most Thurston County residents have access to curbside pickup for yard waste and recyclable materials. Use the online recycling menu to find more recycling options: <www.piercecountywa.org/recyclemenu>. o Purchase products which have the least amount of packaging materials. o Compost biodegradable materials such as grass clippings and vegetable scraps instead of throwing them away. Your flowerbeds will love the finished compost, and you’ll be helping to conserve limited landfill space. Visit <www.piercecountywa.org/compost> or call Thurston County Public Works at (253) 798-2179 for more information on composting or yard waste collection. See the section on composting for BMPs relating to that activity. o A fun alternative to traditional composting is worm composting. You can let worms do all the work for you by keeping a small vermiculture box just outside your kitchen. For more information on getting started with worms, visit <www.piercecountywa.org/compost> or call the number listed above. Composting Composting is an earth-friendly activity as long as some common-sense rules outlined below are followed. If you choose to compost, the following BMPs should be utilized. More information can be found online at: <www.piercecountywa.org/recycle>. Suggested BMPs • Compost piles must be located on an unpaved area where runoff can soak into the ground or be filtered by grass and other vegetation. Compost piles should be located in an area of your yard not prone to water ponding during storms, and should be kept well away from wetlands, streams, lakes, and other drainage paths. • Compost piles must be maintained and turned over regularly to work properly. Large piles of unattended compost may create odor and vermin problems. • Cover the compost pile for two reasons: 1. To keep stormwater from washing nutrients into waterways. 2. To keep excess water from cooling down the pile, which will slow down the rate of decomposition. Build Bins of wood, chicken wire, or fencing material to contain compost so it can't be washed away. Visit <www.piercecountywa.org/compost> to download plans for building your own bin or call Thurston County Public Works at (253) 798-4050. • Building a small earthen dike around your compost pile is an effective means of preventing nutrient-rich compost drainage from reaching stormwater paths. Yard Maintenance and Gardening This section deals with the normal yard maintenance activities we all perform at our homes. 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. Required 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 adjacent to streams, wetlands, or other water bodies. Triple-rinse empty containers, using the rinse 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, organic soil amendments like Thurston County’s SoundGRO Mix. SoundGRO Mix is a 100 percent recycled blend of dewatered, Class A, “Exceptional Quality” biosolids, mixed with sawdust and sand. 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. • 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 Thurston County Conservation District at (253) 845-9770 for advice and assistance in developing a planting plan. The Stream Team at the Conservation District may even be able to help you plant it! • Reduce the need for pesticides and fertilizers on lawns by improving the health of the soil. Aerating, thatching, and topdressing with compost or the City of Tacoma’s Tagro products 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. • Practice organic gardening and virtually eliminate the need to use pesticides and fertilizers. Contact Thurston County Cooperative Extension at (253) 798-7180 or the Ask-A-Master Gardener program at (253) 798-7170 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. • 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 Once we really start looking around our houses, the amount of hazardous materials we have onsite is a real eye-opener. Oil-based paints and stains, paint thinner, gasoline, charcoal starter fluid, cleaners, waxes, pesticides, fingernail polish remover, and wood preservatives are just a few hazardous materials that most of us have around the house. 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 in all homes in Thurston County, 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. Required 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, 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, Tacoma-Thurston County Health Department (253)798-6047, or the Tacoma Solid Waste Utility Household Hazardous Waste at (253) 591- 5418 for information on disposal methods, collection events, and alternative products. Household hazardous wastes from Thurston County residents and non-residents are accepted at the Tacoma Landfill and LRI Landfill. 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. Repair and Maintenance • 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 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). Pet Waste Management Pet waste that washes into rivers, lakes, streams or Puget Sound begins to decay, using up oxygen and releasing ammonia. Low oxygen levels and ammonia combined with warm water can kill fish. Pet waste also contains nutrients that encourage weed and algae growth in waters we use for swimming, boating and fishing. Most importantly, pet waste can carry diseases and bacteria that could make water unsafe for contact and lead to beach closures or effect shellfish harvest. These include: • Campylobacteriosis—bacterial infection • Salmonellosis—bacterial infection • Toxocariasis—roundworm infection • Toxoplasmosis—protozoan parasite infection • Giardiasis—protozoan parasite infection • Fecal Coliform—bacteria in feces, indicates contamination • E. coli—bacteria in feces, may cause disease. Cleaning up after your pet can be as simple as taking a plastic bag or pooper scooper along on your next walk. Then choose one of the following: Suggested BMPs • Bag it – Put waste in a securely closed bag and deposit it in the trash. Do not put it in your yard waste container because pet waste may carry diseases, and yard waste treatment may not kill disease organisms. • Bury it – Bury waste at least 1 foot deep and cover with soil in your yard or garden (not in food-growing areas). • Flush it – Only flush pet wastes if your home is served by a sanitary sewer which goes to a sewage treatment plant. Water from your toilet goes through a treatment process that removes pollutants before it is discharged into the environment. To prevent plumbing problems, don’t flush debris or cat litter. Cat feces may be flushed, but used litter should be put in a securely closed bag in the trash. Septic systems are not designed to accommodate the high pollutant load of pet waste. To prevent premature failure or excessive maintenance costs do not flush pet wastes to your septic system. • Compost it – waste from small animals other than dogs and cats (rabbits, rodents, etc.), can be put in your compost bin. On-Site Sewage Maintenance and Operation Thurston County is responsible for making sure that the stormwater discharged from the stormwater management systems we operate does not harm or impair the use of the receiving waters (streams, rivers, lakes, groundwater or Puget Sound) it discharges into. Sample tests of stormwater discharges and receiving water occasionally indicate high levels of fecal coliform bacteria. One potential source of bacteria is malfunctioning onsite sewage systems (septic systems). Septic system failures have been documented on private property in Thurston County. Septic systems vary widely in their design and complexity. Owners of septic systems should contact the Tacoma-Thurston County Health Department at (253) 798-6577 to request an as- built of their system. As-builts are also available on their Web site at: <www.tpchd.org/septic>. In its simplest design the septic tank is the first stage of a private sewage disposal system. The septic tank is a water-tight tank below ground that is usually made of concrete but may be fiberglass, plastic or steel. Septic tanks have one or two access ports for inspection and maintenance which are usually buried a few inches below the ground. The tank receives household wastewater through an inlet pipe at one end, settles out larger material to the bottom, breaks down waste material with bacteria present in the tank and delivers the partially treated wastewater out another pipe on the opposite end of the tank to the disposal field. The disposal field is the second stage of the private sewage disposal system and completes the final breakdown of wastewater with organisms in the soil. The disposal field consists of narrow trenches filled with gravel and perforated pipes that distribute the wastewater to the field. With proper maintenance, a well-designed system can last a long time; however, disposal fields will clog if forced to handle large particles that should settle out in the bottom of the septic tank. Required BMPs Regular Inspection and Maintenance Owners of septic systems must follow all of the requirements of the Tacoma- Thurston County Health Department (Health Department). Septic systems are required to be inspected on a routine basis. The frequency of inspection is based on the type of septic system being used and is spelled out in the Tacoma-Thurston County Board of Health Resolution No. 2402-4414, Environmental Health Chapter 2 Code, Section 39 through 42. For “high risk” systems the inspections are required annually. Septic system noted as “moderate risk” should be inspected every three years. Those systems classified as “low risk” are to be inspected at time of property sale, land development or upon notification by the Health Department. The inspection should cover each component of the septic system from the septic tank through the final disposal field. Measuring accumulated sludge and scum in the septic tank is an important part of the overall inspection process. Pumping frequency of the septic tank can vary depending on tank size, family size and garbage disposal use. Inspection of the entire system and conducting needed maintenance can find and correct problems before they become major, thereby saving the homeowner in potential high repair cost. Contact the Tacoma-Thurston County Health Department at (253) 798-4788 for further information and specific requirements applicable to your system. Eliminate or Restrict Garbage Disposal Use Eliminating or restricting garbage disposals can significantly reduce the loading of solids to the septic tank thus reducing the pumping frequency. Reduce and Spread Water Use Out Over the Day Septic systems are limited in their ability to handle large amounts of wastewater discharged at one time. Excessive wastewater flow can cause turbulence in the septic tank that may flush accumulated solids into the disposal field. Over time this will impair the ability of the disposal field to function. Limit water using appliances to one at a time. Do one load of clothes a day rather than several in one day. Practice water conservation at home. Chemical Use Septic systems are to be used for the disposal of household wastewater only. Never dispose of excess or unwanted chemicals into the septic system. Occasional use of household cleaners in accordance with the manufacturers’ recommendations should not harm your septic system. Avoid using septic tank additives that advertise their use as septic system cleaners or a substitute for pumping. For additional information on proper operation of your septic system or to report a failing septic system in your neighborhood, contact the Tacoma-Thurston County Health Department at (253) 798-6470 or on the Internet at: <www.tpchd.org>.