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21-101955-SE-Drainage Report 50 Percent-V1 CEMETERY ROAD Preliminary Drainage Report | 50% Draft MC# PTOI-0023 4/8/2021 MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road i P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Preliminary Drainage Report 50% Draft 4/8/2021 Prepared for: Puyallup Tribe of Indians Point of Contact: Jennifer Keating, Project Manager Email: Jennifer.M.Keating@PuyallupTribe-NSN.com Phone: (253) 549-5397 Owner’s Agent: Momentum Civil, LLC. 1145 Broadway, Suite 1150 Tacoma, WA 98402 Prepared by: J. Kyle Murphy, P.E. Under the Direction of: Drew Harris, P.E. Email: DrewH@MomentumCivil.com Phone: 253-319-1504 MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road ii P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Table of Contents Table of Figures......................................................................................................................................................................... iv Table of Tables ........................................................................................................................................................................... iv Table of Appendices .............................................................................................................................................................. iv Section 1 - Project Overview ................................................................................................................................................ 1 Existing Conditions Summary ..................................................................................................................................... 3 Soils Properties ................................................................................................................................................................. 3 Floodplain Analysis ......................................................................................................................................................... 3 Critical Areas ....................................................................................................................................................................... 3 Proposed Conditions Summary ................................................................................................................................. 6 Section 2 – Offsite Analysis ................................................................................................................................................. 8 Upstream Tributary Sub-basin .................................................................................................................................... 8 Downstream Analysis ........................................................................................................................................................ 8 Section 3 – Conditions and Requirements Summary .......................................................................................11 Stormwater Minimum Requirements Summary ............................................................................................11 MR #1 – Discharge at the Natural Location .........................................................................................................11 MR #2 Offsite Analysis .......................................................................................................................................................11 MR #3 – Flow Control Facilities....................................................................................................................................11 MR #4 – Conveyance System ...................................................................................................................................... 12 MR #5 – Construction Stormwater Pollution Prevention (CSWPPP) ................................................. 12 MR #6 – Maintenance and Operations .................................................................................................................. 12 MR #7 – Financial Guarantees and Liability ....................................................................................................... 12 MR #8 – Water Quality Facilities ................................................................................................................................ 12 MR #9 – Flow Control BMPs ......................................................................................................................................... 13 Special Requirement #1: Other Adopted Area-Specific Requirements............................................ 13 Critical Drainage Area .................................................................................................................................................. 13 Master Drainage Plan .................................................................................................................................................. 13 Basin Plans ......................................................................................................................................................................... 13 Salmon Conservation Plans ..................................................................................................................................... 13 Stormwater Compliance Plans .............................................................................................................................. 13 Lake Management Plan ............................................................................................................................................. 13 Flood Hazard Management Plan ......................................................................................................................... 13 Shared Facility Drainage Plans .............................................................................................................................. 13 Special Requirement #2: Flood Hazard Area Delineation ......................................................................... 13 Special Requirement #3: Flood Protection Facilities ................................................................................... 13 MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road iii P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Special Requirement #4: Source Controls ......................................................................................................... 14 Special Requirement #5: Oil Control ..................................................................................................................... 14 Section 4 – Flow Control and Water Quality Analysis and Design .......................................................... 19 Performance Standards ................................................................................................................................................. 19 BMP Modeling ..................................................................................................................................................................... 19 Sub-basin 1 ......................................................................................................................................................................... 19 Sub-basin 2 ........................................................................................................................................................................ 19 Wetland Volumetric Analysis ..................................................................................................................................... 19 Water Quality System .................................................................................................................................................... 20 Section 5: Conveyance System Analysis and Design ...................................................................................... 20 Pipe Capacity Conveyance Analysis ...................................................................................................................... 20 Catch Basin Inlet Spacing and Gutter Flow ..................................................................................................... 20 Culvert Capacity ................................................................................................................................................................. 20 Ditch Capacity Analysis ................................................................................................................................................. 20 Section 6: Special Reports and Studies...................................................................................................................... 21 Section 7: Other Permits ..................................................................................................................................................... 21 Section 8: CSWPPP Analysis and Design ................................................................................................................. 21 ESC Plan Analysis and Design .................................................................................................................................... 21 CSWPP Plan Design ......................................................................................................................................................... 22 Section 9: Bond Quantities, Facilities Summaries, and Declaration of Covenant ......................... 23 Section 10: Operations and Maintenance Manual. ............................................................................................ 23 Project Information .......................................................................................................................................................... 23 System Description ........................................................................................................................................................... 23 Description of Stormwater Facilities .................................................................................................................... 24 Cost Estimate for Maintenance ............................................................................................................................... 24 Stormwater Facility Maintenance Log ................................................................................................................. 25 List of Appendices ..................................................................................................................................................................27 MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road iv P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Table of Figures Figure 1: Vicinity Map .............................................................................................................................................................. 2 Figure 2: Existing Conditions Map ................................................................................................................................. 5 Figure 3: Proposed Basin Map .......................................................................................................................................... 7 Figure 4: Offsite Analysis Map ........................................................................................................................................ 10 Table of Tables Table 1: Cost Estimate for Storm Maintenance ................................................................................................... 24 Table of Appendices Appendix A - Civil Engineering Plans ...................................................................................................................... A-1 Appendix B - Technical Information Worksheet .............................................................................................. B-1 Appendix C - Conveyance Calculations .................................................................................................................. C-1 Appendix D - WWHM Calculations ........................................................................................................................... D-1 Appendix E - Construction Stormwater Pollution Prevention Plan (C-SWPPP) .......................... E-1 Appendix F - Geotechnical Report .............................................................................................................................F-1 Appendix G - Ground Penetrating Radar Survey for the St. George Cemetery ............................ G-1 MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 1 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Section 1 - Project Overview The proposed Cemetery Road project will provide vehicular access to the existing cemetery site owned by the Puyallup Tribe of Indians. The project is located on King County parcel number 322104-9134 at 400 South 376th St. in Federal Way, WA 98003. The parcel has a total lot size of 17.0 acres. This parcel is held in Federal Trust and is under the jurisdiction of the Puyallup Tribe of Indians. Please refer to Figure 1 on the next page for the project Vicinity Map. This roadway project will connect to the existing two-way intersection of 8th Ave S. and S. 376th and form a three-way intersection. The proposed roadway will extend for approximately 1,250 linear feet and be situated within the existing 60-ft recorded access easement (record number 9504100629) prior to its termination. This project will provide stormwater management for the roadway which will include the following elements: permeable pavement, a collection and conveyance system for the impervious pavement portion, a media treatment device for runoff from the proposed impervious roadway, and gravel filled dispersal trenches. This Technical Information Report discusses the applicable stormwater requirements and design calculations for the project. The design of the storm system as been prepared following the 2016 King County Stormwater Design Manual (KCSWDM) and the City of Federal Way Addendum to the 2016 KCSWDM, dated January 8th, 2017. MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 2 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Figure 1: Vicinity Map Project Site S 376th St MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 3 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Existing Conditions Summary The subject parcel is approximately 17.0 acres in size and is in Federal Way, Washington to the south of 376th Street. The parcel is bounded by Interstate 5 (I-5) to the east, and forested (undeveloped) properties to the north, west and south. Access will be provided to the site by means of a 60-ft access easement running along the eastern edge of the adjacent parcel (King County Tax Parcel 322104-9134). The subject parcel and the area within the access easement are undeveloped and forested. Historically, portions of the site were used as a cemetery and have an unknown number of historical graves belonging to the Puyallup Tribe of Indians. These graves are predominantly located in the northern portion of the subject parcel, in the area bordering Saint George Cemetery (KC tax parcel 322104-9025) The Tribe wishes to have access to this historic property and preserve, protect, and potentially expand the cemetery for future use. Please see Figure 2 for representation of the existing conditions. Soils Properties The geotechnical engineering study prepared by South Sound Geotechnical Consulting, dated January 7, 2020, describes the soils in the lower (southern) region as approximately 6 inches to 1 foot of topsoil underlain by 1.5 feet to 4 feet of native silty sand with occasional gravel, which is representative of weathered native soil. Below this layer was silty sand with gravel in a medium dense to dense condition, which is representative of sandy glacial til up to the termination depth of the test pits. The test pits were fairly uniform cross the sampled alignment; however, no test pits were located in the immediate vicinity of the wetlands or creek (see the geotechnical engineering study under Appendix F for further enumeration on soil characteristics). High groundwater and silty soils described in the geotechnical engineering study indicate that infiltration is inadvisable near the lower (southern) portion of the project. Infiltration is feasible for the northern segment of road, which had a long- term factored infiltration rate of 1.26 in/hr. Floodplain Analysis The project site is located outside the 100-year flood plain as identified by the FEMA FIRM panel 1250G of King County, Washington. Critical Areas West Hylebos Creek transects the site from north to south in roughly equivalent halves and has a 100-ft buffer from the mapped creek limit according to the Puyallup Tribe’s environmental department. Additionally, three wetlands are present onsite: a depressional wetland (known as wetland #1) with an associated buffer of 50- ft; a riverine wetland (known as wetland #2) with an associated buffer of 100-ft; and a slope wetland (known as wetland #3) with an associated buffer of 25-ft. Please refer to the Critical Areas Report which is included under separate cover. Moderate slopes (5%-15%) are present throughout the project area, with some areas steeper than 20%. The topography is flatter in the recessional areas near West Hylebos Creek and the identified wetlands. MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 4 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx The subject parcel is home to several historical graves belonging to the Puyallup Tribe of Indians. In an effort to preserve these grave sites from disruption caused by construction, a ground penetrating radar survey was performed in the northeast corner of the site and along the lower edge of the historic cemetery. This survey was performed by the Central Washington Anthropological Survey team of Central Washington University. Their reports, prepared February 2021, are included as Appendix G of this report. To avoid impacting any historical grave sites, this project will terminate the road at the subject parcel property line, and the onsite stormwater management system will minimize trench work within this critical area to the greatest extent feasible. © 2021 Microsoft Corporation © 2021 Maxar ©CNES (2021) Distribution A i r b u s D S S59°38'40"E524.65'S59°38'40"E160.00'S59°36'38"E 60.50' N37°55'47"E 242.46' N37°55'47"E 310.30'S52°04'13"E75.00'S52°04'13"E75.00'N37°55'47"E 457.32' N37°55'47"E 686.11' N26°11'43"E 5 3 2 . 4 7 ' S88°25'12"E 22.02'N01° 2 3' 4 0" E 2626. 7 2'( M) S30°22'04"W 49.86'N59°37'56"W 6.62' S37°55'47"W 227.05' N34°32'15"E 456.03' N53°47'09"W 49.94' Δ=1°43 '57"R=7965.00'L=2 40.85'N59°37'56"W578.33'N30°07'24"E 49.88' 295.00' 237.47' S30°22'04"W 0.14'20.00'20.00'6TH AVE. S. / K . C . R D . 2 0 0 INTERSTATE 5 8TH A V E. S. S. 376TH ST .PARCEL ATAX PARCEL NO .322104-9134xxxxxxxxxxxxxxxxxxWETWETWETWETWETWETWETWETWETWETWETWETWE T WET WETWE T WETWETWET5' CLF 4' BWF xxxxBARN 6' WDF 4' BWF 4' BWF 4' BWF 3' BWF 4' BWF 4' BWF SHED3' BWF NE , 4 ' BWF SW5' CLF NE , 4 ' BWF SWGATEGATEGATEAWNING 4 ' BWF INDISREPA IR WF1- 1 WF1 -2WF1- 3 WL 1 -DP2WL 1 -DP1WF1 -4WF1- 5WF1- 6WF1 -7WL 1 -DP3WF1 -8WF1 -9WF1 -10WF1 -11WF1- 12WL3-DP2WF3 -101WF3- 102 WETWETWETWETWETWET WF3- 7 WF3- 6 WF3- 5WL 3 -DP1WF3 -4WF3 -3WF3 -2WF3- 1WF3- 0 WF2 -11WL2 -DP3WF2- 111WF2 -112WF2- 1 10 WF2- 109 WF2 -108WF2- 1 0 WF2 -9WF2 -107WF2 -10 6WF2- 1 05 WF2- 104 WF2 -103WF2 -10 2 WL2 -DP2WF2- 101WL2 -DP1WF2- 3 WF2- 2 WF2 -8WF2-4WF2- 5 WF2 -6WF2- 7 WF2- 1 WF2- 1 WETLAND #3WETLAND #1WETLAND #2WF3- 103 ?????10+00 11+00 12+00 13+00 14+00 15+ 0 0 16+00 17+00 18+00 19+00 20+00 21+00 22+00 23+00 24+00 24+50 WETLAND #1 TRIB. AREA: 7.18±AC SUB-BASIN #3 AREA: 0.57±AC SUB-BASIN #2 AREA: 0.17±AC SUB-BASIN #1 AREA: 0.40±AC30405060708090100110120130140 150 32 343638424446485254 56 5862646668727476788284868892 94 96 98 102 104 106 1081121141 16 118122 124 126 128 132134136138142144146 148 152 1 0 0 11 0 120 130 130 130130 13 0 1 4 0 140 14015 0 9 6 9 8 1 0 2 1 0 4 1 0 6 108 11211 2 112114114114 116 118122 124 126128 132134 134 134136136 13613 8 138 1381 4 2142 142 144146146 14614815 2 152 1526 0 7 0 80 54 565 8 6 2 6 4 6 6 6 8 7 2 7 4 76 78 605 4 5 6 586230 30 40 40 50 60 70 28 28 32 3234 3436 36 38 38 42 42 44 44 46 46 48 48 52 54 56 58 62 64 66 68 72 74 76 WETLAND #1 WETLAND #3 WETLAND #2 PROJECT NO. DRAWN BY: DESIGNED BY:DATENO.REVISION DESCRIPTIONCKBYDATE: SHEET NO.Save Date: Plot Date: 4/8/2021 2:18 PM4/8/2021 2:19 PMBy: KyleMurphyP:\P\PTOI0023\0400CAD\Exhibits\Existing Basin Map - PTOI23.dwgKyle MurphyBy: File:CHECKED BY: 1145 BROADWAY, SUITE 115 TACOMA, WA 98402 PHONE: 253.319.1504 VERT. DATUM: HORZ. DATUM: REFERENCE NO. A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M. 50 PERCENT PTOI0023 FIG2 X OF XX FEDERAL WAY, WA4/5/21CEMETERY ROAD PUYALLUP TRIBE OF INDIANSEXISTING BASIN MAPDRAFT HORZ. DATUM VERT. DATUM AKH JKM MAP NORTH LEGEND EXISTING CONTOURS WETLAND BUFFER PROJECT LIMITS EASEMENT LINE RIGHT-OF-WAY LINE PROPERTY LINE CREEK CENTERLINE TOTAL AREA OF DISTURBANCE: 1.14± AC MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 6 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Proposed Conditions Summary A new roadway, extending approximately 1,250 lineal feet, will connect the existing intersection of South 376th St and 8th Ave S to the subject property. The typical roadway section will include two 12-foot lanes, wedge curb, interception ditches and catch slopes. No other improvements beyond providing vehicular access is proposed at this time. This project will introduce approximately 0.60 acres of impervious roadway, 0.30 acres of permeable roadway, resulting in a total disturbed area of approximately 1.14 acres. The proposed developed area will be less than 35% of the entire parcel area (plus its associated easement), with less than 15% of that area impervious, which is compatible with the requirements for “Full Dispersion.” The proposed roadway improvements will have a storm drainage system that will provide both stormwater quantity and quality control in accordance with the 2016 KCSWDM and the City of Federal Way Addendum to the 2016 KCSWDM. Stormwater quantity control will be accomplished by utilizing full dispersion for all impervious surfaces and usage of permeable pavement where infiltration is feasible. Full dispersion of impervious roadway surfaces will be accomplished by use of a gravel filled trenches and native vegetative flow segments in excess of 100-feet. Enhanced basic water quality treatment will be provided by a media treatment device and by permeable pavement. Stormwater from the impervious pavement section will be collected, conveyed, and discharged down-gradient of the project via the gravel filled dispersal trenches. The permeable pavement section will infiltrate into the native soil which has sufficient cation exchange capacity to treat the runoff. See Section 4 of this report for further discussion of the stormwater quantity and quality control. Since the proposed roadway alignment is downhill of an undeveloped forested area that sends runoff across the proposed roadway alignment, a ‘V’ channel ditch will be introduced to intercept runoff and divert it into two roadside culverts. These culverts will be located to preserve the natural drainage basins of the surrounding area and discharge water overland. No wetlands will be impacted by the proposed project, and the design team has taken careful consideration and planning to avoid disrupting any historical grave sites. To this end, minimal trench work will be performed near the historical Saint George Cemetery site. Please see Figure 3 for representation of the proposed conditions. © 2020 Microsoft Corporation © 2020 DigitalGlobe ©CNES (2020) Distribution Airbus DS 6TH AVE. S. / K . C . R D . 2 0 0 INTERSTATE 5 8TH A V E. S. S. 376TH ST .PARCEL ATAX PARCEL NO .322104-9134xxxxxxxxxxxxxxxxxxWETWETWETWETWETWETWETWETWETWETWETWETWE T WET WETWE T WETWETWET5' CLF 4' BWF xxxxBARN 6' WDF 4' BWF 4' BWF 4' BWF 3' BWF 4' BWF 4' BWF SHED3' BWF NE , 4 ' BWF SW5' CLF NE , 4 ' BWF SWGATEGATEGATEAWNING 4 ' BWF INDISREPA IRWETWETWETWETWETWET ?????LIMIT LIMIT LIMIT LIMIT LIMIT LIMIT LIMIT LIMIT LIMITLIMITLIMIT LIMIT LIMI T Save Date: Plot Date: 4/8/2021 2:35 PM4/8/2021 2:35 PMBy: KyleMurphyP:\P\PTOI0023\0400CAD\Exhibits\Proposed Basin Map - PTOI23.dwgKyle MurphyBy: File:1145 BROADWAY, SUITE 115 TACOMA, WA 98402 PHONE: 253.405.4474 MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 8 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Section 2 – Offsite Analysis Upstream Tributary Sub-basin The proposed roadway will be situated within a forested region which generally slopes from the northeast to the southwest. The roadway will cause interception of runoff generated from the uphill forested region (approximately 0.79 acres in size and approximately 50 feet in width). To preserve the natural flow pattern of the upstream tributary area, as well as separate the proposed roadway runoff from offsite runoff, an interception ditch will be located on the east (high) side of the roadway. This interception ditch will convey water to two (2) proposed culverts which will allow passage of flow under the roadway. Please refer to Figure 2 for the existing conditions map and the upstream tributary areas. Downstream Analysis A Level 1 Downstream Analysis was conducted for the site. The analysis follows the four tasks required for a downstream analysis. Task 1: Define and map the study area The study area for the downstream analysis consists of the project site and West Hylebos Creek within ¼ mile of the project site discharge point. Task 2: Review all available information on the study area Mapping and stormwater records (including complaints) from King County and from the City of Federal Way were reviewed as part of the downstream analysis. Task 3: Field inspect the study area Momentum Civil engineering staff walked the downstream on multiple occasions during the summer and fall of 2020 during both rainy and sunny days. Task 4: Drainage System Description and Problem Descriptions For the southern portion of the roadway, runoff is collected, treated and discharged into Wetland #1 which eventually outflows to West Hylebos Creek. For the northern portion of the roadway, runoff is fully infiltrated through permeable pavement. The project site is mapped as having erosion hazards present by the DNRP. No severe flooding problems were identified on site or within ¼ mile downstream of the site. There are no known drainage complaints noted for the parcel with King County. There are no known severe erosion, or severe flooding problems on the project site or within ¼ mile downstream of the site. There are two identified wetlands located within ¼ mile downstream of the project site (Wetland #1 and Wetland #3 as identified in the Critical Areas Report). Volumetric flows entering the wetlands will conform to the requirements MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 9 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx established by Reference 5 in the KCSWDM. Please refer to Section 4 of this report for further information regarding volumetric fluctuations and analysis for the wetlands. Please see Figure 4 for representation of the Offsite Qualitative Analysis. N01°43'11"E2,117.41'N88°24'41"W 2,248.98' S 4 5 ° 0 4 ' 3 3 " E 1 , 1 8 0 . 3 2 ' S 4 5 ° 0 4 ' 3 3 " E 6 9 9 . 4 4 ' S 4 5 ° 0 4 ' 3 3 " E 1, 2 0 5 . 6 2 'N01°18'05"W588.21'N74°29'4 1 " E 414.67' S5 9 ° 3 8 ' 4 0 " E 52 4 . 6 5 ' S5 9 ° 3 8 ' 4 0 " E 16 0 . 0 0 ' S59°36'38"E 60.50'N37°55'47"E242.46'N37°55'47"E310.30'S 5 2 ° 0 4 ' 1 3 " E 7 5 . 0 0 ' S 5 2 ° 0 4 ' 1 3 " E 7 5 . 0 0 'N37°55'47"E457.32'N37°55'47"E686.11'N26°11'43"E 532.47'S88°25'12"E 22.02'N01°23'40"E 2626.72'(M)N88°24'41"W 379.88' S30°22'04"W 49.86' N59°37'56"W 6.62'S37°55'47"W 227.05'N34°32'15"E456.03'N53°47'09"W 49.94'Δ=1°43'57"R=7965.00'L=240.85'N5 9 ° 3 7 ' 5 6 " W 57 8 . 3 3 ' N30°07'24"E 49.88'295.00'237.47'S30°22'04"W 0.14' 20. 0 0 ' 20. 0 0 '6TH AVE. S. / K.C. RD. 200INTERSTATE 58TH AVE. S. S. 376TH ST. PARCEL A TAX PARCEL NO. 322104-9134 xxxxxxxxWETWETWETWETWETWETWETWET WET 5' CLF4' BWFxxBARN6' WDF4' BWF 4' BWF 4' BWF 3' BWF 4' BWF 4' BWF SHED 3' BWF NE, 4' BWF SW 5' CLF NE , 4' BWF SW GATE GATE GATE AWNING 4' BWF IN DISREPAIR WF1-1 WF1-2 WF1-3 WL1-DP2 WL1-DP1 WF1-4 WF1-5 WF1-6 WF1-7 WL1-DP3 WF1-8 WF1-9 WF1-10 WF1-11 WF1-12 WL3-DP2 WF3-101 WF3-102 W E T WETWET WF3-7 WF3-6 WF3-5 WL3-DP1 WF3-4 WF3-3WF3-2 WF3-1 WF3-0 WF2-11 WL2-DP3 WF2-111 WF2-112 WF2-110 WF2-109 WF2-108 WF2-10 WF2-9 WF2-107 WF2-106 WF2-105 WF2-104 WF2-103 WF2-102 WL2-DP2 WF2-101 WL2-DP1 WF2-3 WF2-2 WF2-8 WF2-4 WF2-5 WF2-6 WF2-7 WF2-1 WF2-1 WF2-2 WETLAND #3 WETLAND #1 WETLAND #2 WF3-103 ? ? ? ? ? PROPOSED ROADWAY 635LF CREEK FLOW PATH 1/4 MILE DOWN STREAM OF PROJECT OUTFALL 684LF OVERLAND FLOW PATH TO WEST HYLEBOS CREEK WEST HYLEBOS CREEK WEST HYLEBOS CREEK 30 304 0 4050506060707080809090100100 110120 13014015030304040505060607070808090 90100100100 11012013014 0 3030 405060 70 80 901001 0 0 1 10 1 2 0 13 0 1 4 0 1 5 0 PROJECT NO. DRAWN BY: DESIGNED BY:DATENO.REVISION DESCRIPTIONCKBYDATE: SHEET NO.Save Date: Plot Date: 4/7/2021 10:27 AM4/7/2021 10:32 AMBy: KyleMurphyP:\P\PTOI0023\0400CAD\Exhibits\Downstream Analysis Exhibit.dwgKyle MurphyBy: File:CHECKED BY: 1145 BROADWAY, SUITE 115 TACOMA, WA 98402 PHONE: 253.319.1504 VERT. DATUM: HORZ. DATUM: REFERENCE NO. A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M. 50 PERCENT PTOI0023 FIG4 X OF XX FEDERAL WAY, WA4/5/21CEMETERY ROAD PUYALLUP TRIBE OF INDIANSOFFSITE ANALYSIS MAPDRAFT HORZ. DATUM VERT. DATUM AKH JKM MAP NORTH MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 11 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Section 3 – Conditions and Requirements Summary Stormwater Minimum Requirements Summary Figure 1.1.2.A of the 2016 King County Surface Water Design Manual was used to determine that a full drainage review is necessary for the project. The flow chart and selection process are provided in Figure 5. The requirements for a full drainage review are listed in Table 1.1.2.A of the 2016 King County Surface Water Design Manual which is provided in Figure 6 The project will comply with Core Requirements #1 through #9 and Special Requirements #1 through #5. Each requirement is listed below with a discussion of how the project will comply with these requirements (if applicable to the project). MR #1 – Discharge at the Natural Location In the existing condition, runoff from the project site flows overland into three sub- basins: West Hylebos Creek receives runoff from the central and southern portions of the project site, Wetland #1 (which is hydraulically connected to West Hylebos Creek) receives runoff from the southern portion of the site, and the northern portion of the site fully infiltrates prior to runoff entering West Hylebos Creek. In the developed condition, a portion of the existing tributary area to Wetland #1 will be converted to hardscape and the collected runoff will be discharged via gravel filled dispersion trenches. Two (2) proposed culverts will cross under the proposed roadway which will allow offsite overland runoff to continue to cross the new roadway and enter West Hylebos Creek. Permeable pavement will be utilized along the north section of the proposed roadway. In this manner, the natural discharge locations leaving the project site will be maintained. Please refer to Figure 2 for the existing conditions basins map. MR #2 Offsite Analysis See Section 2 for discussion of the Offsite Analysis. MR #3 – Flow Control Facilities Based on review of the City of Federal Way Flow Control Applications Map (Figure 7), the site is located within a Conservation Flow Control Area. Per Table 1.2.3.A of the KCSWDM, Level 2 flow control is applicable for Conservation Flow Control Areas with no downstream problems. Level 2 flow control dictates that all targeted surfaces in the developed condition must match historic durations for 50% of the 2-yr through 50-yr peaks and must match the historic 2- and 10-year peaks. Since all proposed impervious surface coverage will be fully dispersed, there are no target surfaces requiring Level 2 Flow Control. The total proposed impervious coverage area will be no more than 15% of the total area of native vegetated surface being preserved, and the total area of impervious surface plus non-native pervious surface being fully dispersed is less than 35% of the threshold discharge area. For the southern portion of the roadway (south of station 18+90), the Best Management Practice (BMP) that will be used to fully disperse runoff is gravel filled MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 12 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx dispersal trenches followed by a 100-foot native vegetated flowpath segment. From thence, runoff will proceed overland for approximately 115 feet prior to discharge into Wetland #1. For the northern portion of the roadway (north of station 18+90), the Best Management Practice (BMP) that will be used to provide flow control is permeable pavement. The factored infiltration rate provided by the geotechnical investigation is reported as 1.26 in/hour. This factored rate was used in conjunction with WWHM to design the permeable pavement section. Since the proposed road alignment will impact the tributary area for Wetland #1, a volumetric analysis for Wetland #1 was performed based on the criteria established within Reference 5 of the KCSWDM. The proposed change in basin flow for Wetland #1 does not alter volumetric runoff amounts entering Wetland #1 beyond the tolerance limits — please refer to Appendix D for the volumetric fluctuation data calculated by WWHM. MR #4 – Conveyance System This project proposes collecting runoff from the impervious pavement section and conveying it to the south (downhill) portion of the project site. The proposed catch basin and pipe system will be designed to convey and contain (at a minimum) the 25-year peak flow. Please refer to Section 5 for the Conveyance System Analysis. MR #5 – Construction Stormwater Pollution Prevention (CSWPPP) A Temporary Erosion and Sediment Control Plan has been prepared as sheet C2.0 of the civil plans for this project which describes project specific measures to take based on King County Best Management Practices as adopted by the City of Federal Way. A Construction Stormwater Pollution Prevention Plan addressing the 13 elements will be prepared prior to final design. MR #6 – Maintenance and Operations The drainage facilities constructed as part of this project will be maintained privately. The maintenance requirements for the proposed facilities are included in Section 10. MR #7 – Financial Guarantees and Liability This will be addressed at the final engineering stage. The City and Tribe are working together on a lease agreement for use of the right-of-way. MR #8 – Water Quality Facilities Based on review of the City of Federal Way Water Quality Applications Map (Figure 8), the site is located within a Basic Enhanced Treatment Area. To meet this requirement, a GULD certified media treatment device is proposed for the southern portion of the road and permeable pavement for the northern portion of the site. The media treatment device was sized using the offline 6-month water MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 13 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx quality flow rate reported by WWHM (0.0593 cfs). Further details for the sizing of the facility are provided in Section 4 of this report and the WWHM sizing calculations are included within Appendix D. MR #9 – Flow Control BMPs Implementation of flow control BMPs must occur as part of the proposed roadway project, which falls under the category of ‘Small Road Improvement and Urban Road Improvement Projects’ (inside UGA or on sites/lots less than 5 acres). Full dispersion will be implemented for all proposed impervious surfaces by using gravel filled dispersal trenches with native vegetative flow segments in excess of 100- feet. Special Requirement #1: Other Adopted Area-Specific Requirements Critical Drainage Area There are no known critical drainage areas on or immediately adjacent to the project site. Master Drainage Plan No special drainage requirements are applicable to this project. Basin Plans The project site is in the Hylebos Creek Drainage Basin which is tributary to Puget Sound. The Hylebos Creek and Lower Puget Sound plan, dated 1991, was reviewed. No special drainage requirements were listed in the plan. Salmon Conservation Plans Not applicable to this project, as no salmonid or salmon bearing waters will be impacted. Stormwater Compliance Plans Not applicable. Lake Management Plan Not applicable to this project. Flood Hazard Management Plan Not applicable to this project, as the project site is not within a mapped flood zone. Shared Facility Drainage Plans Not applicable to this project. Special Requirement #2: Flood Hazard Area Delineation Not applicable. This project is not mapped as being within the limits of the 100-year flood plain, zero-rise flood fringe, zero-rise floodway, FEMA floodway or channel migration zones. Special Requirement #3: Flood Protection Facilities Not applicable. MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 14 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Special Requirement #4: Source Controls Source controls will be limited to those materials typical for a roadway development of this type. Source Control Best Management Practices include: • Required BMPs for All roadway projects: Includes Cleaning of Storm Drainage System (Included in Section 10), Elimination of Illicit Connections to the Storm Drainage System (these are not anticipated), and Stenciling of Storm Drains. • No other source controls are anticipated as part of this project. Source controls during construction are covered in Section 8. Special Requirement #5: Oil Control Not applicable as this is not a high-use site because ADT is less than 10,000. MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 15 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Figure 5: Figure 1.1.2.A of the 2016 KCSWDM MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 16 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Figure 6: Table 1.1.2.A of the 2016 KCSWDM MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 17 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Figure 7: City of Federal Way Flow Control Applications Map MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 18 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Figure 8: City of Federal Way Water Quality Applications Map MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 19 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Section 4 – Flow Control and Water Quality Analysis and Design Per Core Requirements #3 and #8, flow and water quality control are applicable for this project. Performance Standards The following Flow Control and Water Quality treatment standards apply to this project: • Level 2 Flow Control • Enhanced Basic Treatment BMP Modeling Sub-basin 1 For Sub-basin 1, flow control will be provided by means of infiltration through permeable pavement. The proposed land cover was modeled entirely as permeable pavement. With the aid of WWHM and a factored infiltration rate of 1.26 in/hr, a permeable pavement section was designed to fully infiltrate runoff volumes for the 100-year storm event without ponding on the pavement surface. Please refer to Appendix D for the calculations and WWHM documentation. Sub-basin 2 For Sub-basin 2, all impervious surface runoff will be fully dispersed by means of gravel filled dispersal trenches prior to discharge over native vegetative flowpath segments 100-feet in length. A flow splitter will distribute runoff among four 50-ft gravel filled dispersal trenches. Each dispersal trench will be parallel to the existing contour of the ground while maintaining a distance of 100-feet from the wetland #1 limits and avoid encroaching within the historical Saint George Cemetery site. The dispersal trenches are sized in accordance with KCSWDM where each 50-foot trench may accept up to 5,000 square feet of impervious surface runoff. Wetland Volumetric Analysis In the existing condition, Wetland #1 has a tributary area of approximately 5.54 acres consisting of forested native growth underlain by type C soils. To protect Wetland #1 from negative impacts of volumetric changes caused by the roadway project, the proposed storm drainage system will have a flow splitter installed that distributes the developed condition runoff between four gravel filled dispersal trenches. Each of the gravel filled dispersal trenches will receive ¼ of the collected and treated volumetric runoff from the impervious roadway. Only one of the four trenches will be tributary to Wetland #1 to closely match the volumetric flows entering Wetland #1 in accordance with Reference 5 of the KCSWDM. The other three gravel filled dispersal trenches will be tributary to West Hylebos Creek, which is immediately downstream of Wetland #1. Please refer to Appendix D for the WWHM wetland volumetric fluctuation results between the proposed and existing conditions. MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 20 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Water Quality System Water Quality Treatment will be provided for developed sub-basins 1 and 2. A GULD certified media treatment device is proposed for the southern portion of the road and permeable pavement for the northern portion of the site. The media treatment device was sized using the offline 6-month water quality flow rate reported by WWHM (0.0593 cfs). Please see Appendix D for the WWHM modeling results used to size the water quality facility. Section 5: Conveyance System Analysis and Design The on-site conveyance system must be designed to convey the 25-year, 24-hour storm event. The proposed site runoff will be collected using gutter flow and catch basins. All collected runoff for sub-basin #2 will be conveyed to the gravel filled dispersion trenches. See Appendix A for stormwater plans showing conveyance system and discharge location. Pipe Capacity Conveyance Analysis The maximum calculated runoff flow is 0.57 cfs for sub-basin 2, as calculated using the Santa Barbara Unit Hydrograph (SBUH) methodology with a presumed time of concentration of 5 minutes, 100-year rainfall intensity of 4.0 in/hr, curve number of 98, and impervious area coverage of 100% for the sub-basin (0.60 ac). The most hydraulically constrained pipe has a minimum diameter of 12 inches and a minimum slope of 0.4% which can convey 2.33 cfs when full. This exceeds the maximum flow rate for the entire project. Therefore, no further analysis is warranted for pipe capacity. Catch Basin Inlet Spacing and Gutter Flow The sub-basin 2 collection system will rely upon gutter flow and collection points with catch basins. The inlet spacing design is consistent with the WSDOT Hydraulics Manual methodology and presumes a roadway classification of ‘Collector and Local Streets’, a standard rectangular vaned grate per WSDOT standard plan B-30.30-03, and a design speed of 15 miles-per-hour. A maximum inlet spacing of 300 feet was observed in order to abide by the City of Federal Way design standards. Please refer to Appendix C for the Inlet Spacing Design Worksheet calculations. Culvert Capacity Two new culverts will be constructed under the proposed roadway to allow bypass of the upstream forested areas. The locations of the culverts have been set to preserve the natural drainage patterns of the tributary areas, conveying the 100-year peak flow. Ditch Capacity Analysis A ‘V’ channel ditch will be constructed along the eastern shoulder of the roadway to convey the intercepted runoff from the upstream forested areas into the culverts. The ‘V’ channel ditch has been sized to convey the 100-year peak flow. Check dams will be added to mitigate against potential erosion. MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 21 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Section 6: Special Reports and Studies A geotechnical engineering study was prepared for the project by South Sound Geotechnical Consulting, dated January 7, 2020, and is included as Appendix F. A cultural resources study was prepared by Central Washington Anthropological Survey, dated February 2021, and is included as Appendix G. This report includes findings from the ground penetrating radar survey performed to assist in identifying historical grave sites. A Critical Areas Report was prepared by David Evans and Associates, Inc., dated December 16th, 202, and is included under separate cover. Section 7: Other Permits The following approvals/permits will likely be needed for the project (this list may not include all the necessary approvals/permits). • SEPA Threshold Determination • NPDES Permit • Clearing and Grading Permit • Right-of-Way Permit • Utility Permits • Building Permit Section 8: CSWPPP Analysis and Design ESC Plan Analysis and Design The project will implement Erosion and Sediment Control (ESC) measures appropriate to the site to minimize the potential for transport of sediment and other impacts related to land disturbing activities. Below is a discussion of each category of ESC measures that are considered for application to the project site. 1. Clearing Limits: The Construction Drawings require the contractor to clearly mark the clearing limits prior to the start of work. 2. Cover Measures: Temporary and permanent cover measures will be implemented to protect disturbed areas during construction. Temporary cover will be implemented if an area is to remain unworked for more than seven days during the dry season (May 1 to September 30) or for more than two consecutive working days during the wet season (October 1 to April 30). 3. Perimeter Protection: Perimeter protection will be provided, where necessary, to reduce the amount of sediment transported beyond the disturbed areas of the site. Silt fence will be incorporated at downhill slopes along the periphery of the project limits. 4. Traffic Area Stabilization: A stabilized construction entrance is proposed at the north corner of the site for construction traffic. A wheel wash may be used by the contractor if a stabilizing construction entrance is not feasible. It should be noted that the contractor will be required to sweep adjacent street on a daily basis if sediment is tracked off the site. MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 22 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx 5. Sediment Retention: temporary sediment traps will be implemented as required to prevent silt laden runoff from leaving the site. Inlet protection will be used at existing inlets that will be subjected to sediment laden runoff. 6. Surface Water Collection: an interceptor ditch will be constructed along the eastern edge of the proposed roadway in order to divert runoff from the adjacent forested areas around the roadway. This interceptor ditch will be lined with rock check dams to prevent erosion and scouring of the ditch and to promote sedimentation. During construction, discharge will be monitored as required in the Washington State General Permit for Stormwater Discharges Associated with Construction Activities. If thresholds are exceeded, ESC measures will be repaired or adjusted to meet the thresholds. 7. Dewatering Control: 8. Dust Control: Wind transport of dust from exposed surfaces will be controlled by spraying exposed soils until wet. Only enough water to wet the soil will be used so that runoff is not generated by spreading. The contractor will also have the option to use the Dust Control Measures designated in Table D.3.8.A of the KCSWDM. These include but are not limited to Salts, Silicates, Surfactants, Copolymers, Lignin Sulfonate, or Spray on Adhesives. 9. Flow Control: 10. Erosion and Sediment Control Performance and Compliance Provisions will include: a. ESC Supervisor: The contractor will design ate an ESC supervisor who will be responsible for the performance, maintenance, and review of ESC measures and for compliance with all permit conditions. b. Monitoring of Discharges: The ESC supervisor will have a turbidity meter onsite and will use it to monitor surface and storm water discharges from the project site. The project site will be covered under the Washington State General Permit for Stormwater Discharges Associated with Construction Activities and will comply with the requirements of that permit. This includes repair or adjustment of ESC measures if thresholds for turbidity or pH are exceeded. c. ESC Performance: If the ESC supervisor determines that the approved measures are not sufficient and that additional action is required due to failure to meet discharge requirements, then additional measures beyond those specified on the Construction Drawings. CSWPP Plan Design The project will implement a stormwater pollution prevention and spill control plan (SWPPS) measures appropriate to the site to minimize the potential for pollution associated with construction activities. Below is a discussion of each category of SWPPS measures that are considered for application to the project site. 1. Concrete Handling: 2. Concrete Washout Area: 3. Material Delivery, Storage and Containment 4. Construction Stormwater Filtration 5. Maintain Protective BMPs 6. Manage the Project MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 23 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx 7. CSWPPP Performance and Compliance Provisions a. CSWPPP Supervisor b. Monitoring of Discharges c. ESC Performance d. SWPPS Performance e. Roads and Utilities Compliance 8. Critical Areas Restrictions Section 9: Bond Quantities, Facilities Summaries, and Declaration of Covenant The bond quantities, facility summaries and declaration of covenant will be prepared after approval of the proposed design. Section 10: Operations and Maintenance Manual. Project Information Address: Parcel No: 322104-9134 King County, WA System Description [The onsite stormwater system contains four (4) catch basins, a stormwater manhole, and two (2) runs of 8-inch PVC pipe: one that runs from CB1, CB2 and CB3 to an existing catch basin within the southwest quadrant of the intersection of South C Street and South Wright Ave; the second pipe run begins at CB4 and terminates at a curb weep hole near the alley apron. The building foundation drain and the site retaining wall drain connect to CB3.] The site will be maintained in compliance with the King County Surface Water Design Manual, 2016. The following pages contain descriptions of the maintenance needs for the components of the drainage system. A maintenance checklist for all system components should be completed on the following schedule: Monthly from November through April Once in later summer (preferably in September) After any major storm (use 1-inch in 24-hours as a guideline) Responsible Party: _______________________ Phone: ___________________________________ Note: A copy of this Operation and Maintenance Manual is to be kept onsite at all times and be available for inspection upon request by the City of Federal Way. MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 24 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Description of Stormwater Facilities Catch Basins/Yard Drains – Catch basins are underground concrete structures typically provided with a slotted grate to collect stormwater runoff and route it through underground pipes. Catch basins can also be used as a junction in a pipe system and may have a solid lid. There are two catch basin types. Both catch basin types typically provide a storage volume (sump) below the outlet pipe to allow sediments and debris to settle out of the stormwater runoff. Some catch basins are also provided with a spill control device (inverted elbow on outlet pipe) intended to contain large quantities of grease or oils within the basin. Yard drains are similar to catch basins in that they are underground structures with slotted grates to collect stormwater runoff and route it through underground pipes. Yard drains are typically smaller than catch basins and made of plastic rather than concrete. Yard drains typically range in size from 6” to 24” in diameter. Pervious Pavement – Permeable pavements allow water to infiltrate into layers of gravel placed below the paving surface and then into soil and groundwater below. By infiltrating most of the storm water on-site, the amount of water and pollution flowing into storm drains and directly to rivers and streams is greatly reduced. This, in turn, protects water quality, maintains more stable base flows to streams, reduces flood peaks, and reduces stream bank erosion. With infiltration, groundwater is recharged and streams are replenished with cool, clean groundwater in a more natural way. Permeable pavements are one component of Low Impact Development (LID). Compost Amended Soil – Naturally occurring (undisturbed) soil and vegetation provide important stormwater functions including: water infiltration; nutrient, sediment, and pollutant adsorption; sediment and pollutant biofiltration; water interflow storage and transmission; and pollutant decomposition. Compaction from construction can reduce the soils natural ability to provide these functions. Establishing a minimum soil quality and depth in the post-development landscape can regain some of these stormwater functions including increased treatment of pollutants and sediments that result from development and habitation, and minimizes the need for some landscaping chemicals. Sufficient organic content is a key to soil quality. Soil organic matter can be attained through numerous amendments such as compost, composted woody material, biosolids, and forest product residuals. Cost Estimate for Maintenance The cost estimate below assumes one worker and necessary equipment would cost $1,000 per day in labor ($200) and equipment costs ($800). Table 1: Cost Estimate for Storm Maintenance Maintenance Activity Frequency Annualized Cost Catch Basin/Yard Drains/Stormfilters MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 25 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Clear all trash/debris/vegetation blocking basin opening Monthly $300 Remove sediment exceeding 60% of sump depth 2x/year $600 Inspect for damage to frame or structure walls Annually $100 Replace Media Cartridge Annually $1,000 Estimate of Total Annual Cost $2,000 Stormwater Facility Maintenance Log Use copies of this log sheet to track when maintenance checks occur, and which items, if any are repaired and altered. The completed sheets will serve as a record of past maintenance activities and will provide valuable information on how your facilities are operating. This information will be useful for future requirements regarding the types of facilities that are installed. Keep all log sheets in a designated area so that others can easily access them. Site Name: Cemetery Road Date: ________ Time: _____________ Site Address: 400 South 376th St., Federal Way, WA 98003 Weather Condition: _____________________ Checked By: ______________________ MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 26 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Part of Facility Checked Observations (Things To Be Done) Follow-up Actions Taken Date Action Taken MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page 27 of 27 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx List of Appendices Appendix A - Civil Engineering Plans ........................................................................................................ A-1 Appendix B - Technical Information Worksheet............................................................................... B-1 Appendix C - Conveyance Calculations ................................................................................................... C-1 Appendix D - WWHM Calculations ............................................................................................................ D-1 Appendix E - Construction Stormwater Pollution Prevention Plan (C-SWPPP) ........... E-1 Appendix F - Geotechnical Report .............................................................................................................. F-1 Appendix G - Ground Penetrating Radar Survey for the St. George Cemetery ............ G-1 MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page A-1 of 1 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Appendix A - Civil Engineering Plans S59°38'40"E524.65'S59°36'38"E60.50'N 3 7 ° 5 5 ' 4 7 " E 2 4 2 . 4 6 ' N 3 7 ° 5 5 ' 4 7 " E 3 1 0 . 3 0 'S52°04'13"E75.00'S52°04'13"E75.00'N 3 7 ° 5 5 ' 4 7 " E 4 5 7 . 3 2 ' N 3 7 ° 5 5 ' 4 7 " E 6 8 6 . 1 1 ' N2 6 ° 1 1 ' 4 3 " E 5 3 2 . 4 7 ' N01°23'40"E 2626.72'(M)S30°22'04"W49.86'N59°37'56"W6.62'S 3 7 ° 5 5 ' 4 7 " W 2 2 7 . 0 5 ' 5'N59°37'56"W578.33'295 . 0 0 ' 237 . 4 7 'S30°22'04"W0.14'20.00'20.00'6T H A V E . S . / K . C . R D . 2 0 0 I N T E R S T A T E 5 8TH AVE. S. S. 376TH ST.WETWET WET WETWET5' C L F??PROJECT NO.DRAWN BY:DESIGNED BY:DATENO.REVISION DESCRIPTION CKBYFIRST SUBMITTAL:SHEET NO.Save Date: Plot Date: 4/1/2021 4:44 PM4/8/2021 3:21 PM By: KyleMurphy P:\P\PTOI0023\0400CAD\Sheets\50 Percent\EC-CV-PTOI000023.dwgKyle MurphyBy: File:CHECKED BY:1145 BROADWAY, SUITE 115TACOMA, WA 98402PHONE: 253.405.4474VERT. DATUM:HORZ. DATUM:REFERENCE NO.CEMETERY ROAD50% ROADWAY AND DRAINAGE PLANSA PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M.50 PERCENTPTOI0023C1.01OF 12FEDERAL WAY, WAKYLE MKYLE MDREW H4/5/21PUYALLUP TRIBE OF INDIANS CIVIL COVER CEMETERY ROAD HORZ. DATUMVERT. DATUM PROJECT NO.DRAWN BY:DESIGNED BY:DATENO.REVISION DESCRIPTION CKBYFIRST SUBMITTAL:SHEET NO.Save Date: Plot Date: 4/1/2021 4:44 PM4/8/2021 3:21 PM By: KyleMurphy P:\P\PTOI0023\0400CAD\Sheets\50 Percent\EC-CV-PTOI000023.dwgKyle MurphyBy: File:CHECKED BY:1145 BROADWAY, SUITE 115TACOMA, WA 98402PHONE: 253.405.4474VERT. DATUM:HORZ. DATUM:REFERENCE NO.” ’” ’A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M.50 PERCENTPTOI0023C1.12OF 12FEDERAL WAY, WAKYLE MKYLE MDREW H4/5/21PUYALLUP TRIBE OF INDIANS GENERAL NOTES CEMETERY ROAD HORZ. DATUMVERT. DATUM XXXXXXXXXXXXXXXXXXXXXXXXLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIMITxx x x x x x x xxxxxxxxxxxxxxxxxxxxxxxxx4' BWF4' BWF4' BWF4' BWF INDISREPAIR?XXXXXXXXXXXXLIMITLIMITLIMITLIMITLIMITLIMITLIMITLIM ITLIMITLIMITLIMITLIMITLIMITLIMIT xx xxxOPOPOPOP6TH AVE. S. / K.C. RD. 2008TH AVE . S . xxxxxxxxxxxxxxxxxxxxxxx5' CLF4' BWFxxxxxxxxxxxxBARNx6' WDF4' BWFx4' BWF3' BWFSHED3' BWF NE, 4' BWF SW5' CLF NE , 4' BWF SWGATEGATEGATEAWNINGXXLIMITPROJECT NO.DRAWN BY:DESIGNED BY:DATENO.REVISION DESCRIPTION CKBYFIRST SUBMITTAL:SHEET NO.Save Date: Plot Date: 4/5/2021 2:03 PM4/8/2021 3:21 PM By: KyleMurphy P:\P\PTOI0023\0400CAD\Sheets\50 Percent\EC-DEMO-TESC-PTOI000023.dwgKyle MurphyBy: File:CHECKED BY:1145 BROADWAY, SUITE 115TACOMA, WA 98402PHONE: 253.405.4474VERT. DATUM:HORZ. DATUM:REFERENCE NO.A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M.50 PERCENTPTOI0023C2.04OF 12FEDERAL WAY, WAKYLE MKYLE MDREW H4/5/21PUYALLUP TRIBE OF INDIANS DEMOLITION AND TESC PLAN CEMETERY ROAD HORZ. DATUMVERT. DATUM 6TH AVE. S. / K.C. RD. 200INTERSTATE 58TH AVE . S . S. 376TH ST.x x x xxxxxxxxxxxxxxxxxxxWETWETWETWETWETWET WETWETWETWET5' CLF4' BWFxxxxxBARN6' WDF4' BWF4' BWF4' BWF3' BWF4' BWF4' BWFSHED3' BWF NE, 4' BWF SW5' CLF NE , 4' BWF SWGATEGATEGATEAWNING4' BWF INDISREPAIRWETWETWETWETWETWET?????L1L2L3L4L5C1C2C3C4L6L1L2L3L4L5L6C4C3C2C1 PROJECT NO.DRAWN BY:DESIGNED BY:DATENO.REVISION DESCRIPTION CKBYFIRST SUBMITTAL:SHEET NO.Save Date: Plot Date: 4/8/2021 3:07 PM4/8/2021 3:22 PM By: KyleMurphy P:\P\PTOI0023\0400CAD\Sheets\50 Percent\EC-RD-OVERALL-PTOI000023.dwgKyle MurphyBy: File:CHECKED BY:1145 BROADWAY, SUITE 115TACOMA, WA 98402PHONE: 253.405.4474VERT. DATUM:HORZ. DATUM:REFERENCE NO.A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M.50 PERCENTPTOI0023C3.05OF 12FEDERAL WAY, WAKYLE MKYLE MDREW H4/5/21PUYALLUP TRIBE OF INDIANS OVERALL ROAD AND DRAINAGE PLAN CEMETERY ROAD HORZ. DATUMVERT. DATUM WETWETWETWET WET WETWETWETWET??L5PROJECT NO.DRAWN BY:DESIGNED BY:DATENO.REVISION DESCRIPTION CKBYFIRST SUBMITTAL:SHEET NO.Save Date: Plot Date: 4/8/2021 3:15 PM4/8/2021 3:22 PM By: KyleMurphy P:\P\PTOI0023\0400CAD\Sheets\50 Percent\EC-RD-PP-PTOI000023.dwgKyle MurphyBy: File:CHECKED BY:1145 BROADWAY, SUITE 115TACOMA, WA 98402PHONE: 253.405.4474VERT. DATUM:HORZ. DATUM:REFERENCE NO.A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M.50 PERCENTPTOI0023C3.16OF 12FEDERAL WAY, WAKYLE MKYLE MDREW H4/5/21PUYALLUP TRIBE OF INDIANS ROAD AND DRAINAGE PLAN AND PROFILE CEMETERY ROAD HORZ. DATUMVERT. DATUM xxx x x x x x xxxxxxxxxxxxxxxxxxxxxxxxx4' BWF4' BWF4' BWF4' BWF INDISREPAIRL1L2C1C3L6 PROJECT NO.DRAWN BY:DESIGNED BY:DATENO.REVISION DESCRIPTION CKBYFIRST SUBMITTAL:SHEET NO.Save Date: Plot Date: 4/8/2021 3:15 PM4/8/2021 3:22 PM By: KyleMurphy P:\P\PTOI0023\0400CAD\Sheets\50 Percent\EC-RD-PP-PTOI000023.dwgKyle MurphyBy: File:CHECKED BY:1145 BROADWAY, SUITE 115TACOMA, WA 98402PHONE: 253.405.4474VERT. DATUM:HORZ. DATUM:REFERENCE NO.A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M.50 PERCENTPTOI0023C3.27OF 12FEDERAL WAY, WAKYLE MKYLE MDREW H4/5/21PUYALLUP TRIBE OF INDIANS ROAD AND DRAINAGE PLAN AND PROFILE CEMETERY ROAD HORZ. DATUMVERT. DATUM xx xx x OPOPOPOP6TH AVE. S. / K.C. RD. 2008TH AVE . S . xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxBARNx6' WDF4' BWFx4' BWF3' BWFSHED3' BWF NE, 4' BWF SW5' CLF NE , 4' BWF SWGATEGATEGATEAWNINGL3L 4C2C4 x xxxxxxxxxxL4 C4 PROJECT NO.DRAWN BY:DESIGNED BY:DATENO.REVISION DESCRIPTION CKBYFIRST SUBMITTAL:SHEET NO.Save Date: Plot Date: 4/8/2021 3:15 PM4/8/2021 3:22 PM By: KyleMurphy P:\P\PTOI0023\0400CAD\Sheets\50 Percent\EC-RD-PP-PTOI000023.dwgKyle MurphyBy: File:CHECKED BY:1145 BROADWAY, SUITE 115TACOMA, WA 98402PHONE: 253.405.4474VERT. DATUM:HORZ. DATUM:REFERENCE NO.A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M.50 PERCENTPTOI0023C3.38OF 12FEDERAL WAY, WAKYLE MKYLE MDREW H4/5/21PUYALLUP TRIBE OF INDIANS ROAD AND DRAINAGE PLAN AND PROFILE CEMETERY ROAD HORZ. DATUMVERT. DATUM PROJECT NO.DRAWN BY:DESIGNED BY:DATENO.REVISION DESCRIPTION CKBYFIRST SUBMITTAL:SHEET NO.Save Date: Plot Date: 4/8/2021 3:15 PM4/8/2021 3:22 PM By: KyleMurphy P:\P\PTOI0023\0400CAD\Sheets\50 Percent\EC-RD-PP-PTOI000023.dwgKyle MurphyBy: File:CHECKED BY:1145 BROADWAY, SUITE 115TACOMA, WA 98402PHONE: 253.405.4474VERT. DATUM:HORZ. DATUM:REFERENCE NO.A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M.50 PERCENTPTOI0023C3.49OF 12FEDERAL WAY, WAKYLE MKYLE MDREW H4/5/21PUYALLUP TRIBE OF INDIANS ROAD AND DRAINAGE DETAILS CEMETERY ROAD HORZ. DATUMVERT. DATUM PROJECT NO.DRAWN BY:DESIGNED BY:DATENO.REVISION DESCRIPTION CKBYFIRST SUBMITTAL:SHEET NO.Save Date: Plot Date: 9/3/2020 10:24 AM4/8/2021 3:22 PM By: KyleMurphy P:\P\PTOI0023\0400CAD\Sheets\50 Percent\EC-TESC-DET-PTOI000023.dwgKyle MurphyBy: File:CHECKED BY:1145 BROADWAY, SUITE 115TACOMA, WA 98402PHONE: 253.405.4474VERT. DATUM:HORZ. DATUM:REFERENCE NO.A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M.50 PERCENTPTOI0023C4.010OF 12FEDERAL WAY, WAKYLE MKYLE MDREW H4/5/21PUYALLUP TRIBE OF INDIANS TESC NOTES AND DETAILS CEMETERY ROAD HORZ. DATUMVERT. DATUM PROJECT NO.DRAWN BY:DESIGNED BY:DATENO.REVISION DESCRIPTION CKBYFIRST SUBMITTAL:SHEET NO.Save Date: Plot Date: 9/3/2020 10:24 AM4/8/2021 3:22 PM By: KyleMurphy P:\P\PTOI0023\0400CAD\Sheets\50 Percent\EC-TESC-DET-PTOI000023.dwgKyle MurphyBy: File:CHECKED BY:1145 BROADWAY, SUITE 115TACOMA, WA 98402PHONE: 253.405.4474VERT. DATUM:HORZ. DATUM:REFERENCE NO.A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M.50 PERCENTPTOI0023C4.111OF 12FEDERAL WAY, WAKYLE MKYLE MDREW H4/5/21PUYALLUP TRIBE OF INDIANS TESC NOTES AND DETAILS CEMETERY ROAD HORZ. DATUMVERT. DATUM ISOMETRIC VIEWAPLAN VIEWABPU-IBBioretention/BiofiltrationPh: 800.579.8819 | oldcastlestormwater.comINFRASTRUCTUREdNAUS Patents PendingSECTION A-ABPU-IBBioretention/BiofiltrationPh: 800.579.8819 | oldcastlestormwater.comINFRASTRUCTUREdNRUS Patents PendingSAUDFI 1325-0510USA XXXXTHIS DOCUMENT IS THE PROPERTY OF OLDCASTLE INFRASTRUCTURE, INC. IT IS SUBMITTED FOR REFERENCE PURPOSES ONLY AND SHALL NOT BEUSED IN ANY WAY INJURIOUS TO THE INTERESTS OF SAID COMPANY. COPYRIGHT © 2018 OLDCASTLE INFRASTRUCTURE, INC. ALL RIGHTS RESERVED.THIS DOCUMENT IS THE PROPERTY OF OLDCASTLE INFRASTRUCTURE, INC. IT IS SUBMITTED FOR REFERENCE PURPOSES ONLY AND SHALL NOT BEUSED IN ANY WAY INJURIOUS TO THE INTERESTS OF SAID COMPANY. COPYRIGHT © 2018 OLDCASTLE INFRASTRUCTURE, INC. ALL RIGHTS RESERVED.MODELVAULT SIZE 1(ID)VAULTFOOTPRINT 1(OD)TREATMENTFLOWCAPACITY 2(GPM/CFS)TREATMENTFLOWCAPACITY 3(GPM/CFS)A DIMB DIMA1 DIMB1 DIMBPU-IB-464'6'5'7'25.6 / 0.05728.8 / 0.064BPU-IB-484'8'5'9'38.4 / 0.08643.2 / 0.096BPU-IB-4124'12'5'13'64.0 / 0.14372.0 / 0.160BPU-IB-666'6'7'7'38.4 / 0.08643.2 / 0.096BPU-IB-686'8'7'9'57.6 / 0.12864.8 / 0.144BPU-IB-6126'12'7'13'96.0 / 0.214108.0 / 0.241BPU-IB-8168'16'9'17'179.2 / 0.399201.6 / 0.4491 All Dimensions Are Nominal2 Based on an WA Ecology GULD Approval for Basic, Enhanced & Phosphorus. At 1.60 gpm/sf Media Surface Area.3 Based on an NJCAT Verification & NJ DEP Certification. At 1.80 gpm/sf Media Surface Area.fdOldcastleStormwater SolutionsdOldcastleStormwater SolutionsdOldcastleStormwater Solutions FIDSAUXXXXUSA DFI11540010FIDSAUXXXXUSA DFI11540010SITE SPECIFIC DATASTRUCTURE ID1MODEL SIZEBPU-48IBORIENTATION (LEFTOR RIGHT)LEFTTREATMENT FLOWRATE (CFS)0.0593 (OFFLINE)PEAK FLOW RATE(CFS)0.532 (100YR)RIM ELEVATION90.10PIPE DATAPIPELOCATION(FRONT ORSIDE)PIPE SIZEPIPE TYPEINVERTELEVATIONINLETSIDE12PVC89.66OUTLETSIDE12HDPE88.69NOTES:PROJECT NO.DRAWN BY:DESIGNED BY:DATENO.REVISION DESCRIPTION CKBYFIRST SUBMITTAL:SHEET NO.Save Date: Plot Date: 4/8/2021 3:19 PM4/8/2021 3:22 PM By: KyleMurphy P:\P\PTOI0023\0400CAD\Sheets\50 Percent\EC-DET-PTOI000023.dwgKyle MurphyBy: File:CHECKED BY:1145 BROADWAY, SUITE 115TACOMA, WA 98402PHONE: 253.405.4474VERT. DATUM:HORZ. DATUM:REFERENCE NO.A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M.50 PERCENTPTOI0023C4.213OF 12FEDERAL WAY, WAKYLE MKYLE MDREW H4/5/21PUYALLUP TRIBE OF INDIANS CIVIL DETAILS CEMETERY ROAD HORZ. DATUMVERT. DATUM PROJECT NO.DRAWN BY:DESIGNED BY:DATENO.REVISION DESCRIPTION CKBYFIRST SUBMITTAL:SHEET NO.Save Date: Plot Date: 4/8/2021 3:19 PM4/8/2021 3:22 PM By: KyleMurphy P:\P\PTOI0023\0400CAD\Sheets\50 Percent\EC-DET-PTOI000023.dwgKyle MurphyBy: File:CHECKED BY:1145 BROADWAY, SUITE 115TACOMA, WA 98402PHONE: 253.405.4474VERT. DATUM:HORZ. DATUM:REFERENCE NO.A PORTION OF THE SW QUADRANT OF SECTION 32, T21N, R4E OF W.M.50 PERCENTPTOI0023C4.314OF 12FEDERAL WAY, WAKYLE MKYLE MDREW H4/5/21PUYALLUP TRIBE OF INDIANS CIVIL DETAILS CEMETERY ROAD HORZ. DATUMVERT. DATUM 6"18"ASPHALTIC CONCRETEPAVEMENT, VARIABLE DEPTHWEDGE CURBHMA WEDGE CURB DOWNHILL SIDE OF STREET CROSS SLOPE3"12"ASPHALTIC CONCRETEPAVEMENT, VARIABLE DEPTHWEDGE CURBFLOWLINEFLOWLINEHMA WEDGE CURB STANDARD MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page B-1 of 6 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Appendix B - Technical Information Worksheet Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner Puyallup Tribe of Indians Phone (253) 573-7879 Address Portland Ave East Tacoma, WA 98404 Project Engineer Andrew Harris, P.E. Momentum Civil Phone (253) 319-1506 Project Name Cemetery Road DDES Permit # N/A Location Township 21N Range 4E Section 32 Site Address 400 S. 376th St, Federal Way, WA 98003 Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS Landuse Services Subdivision / Short Subd. / UPD Building Services M/F / Commercial / SFR Clearing and Grading Right-of-Way Use Other DFW HPA Shoreline Management COE 404 Structural DOE Dam Safety Rockery/Vault/Wall FEMA Floodplain ESA Section 7 COE Wetlands Other: • Part 5 PLAN AND REPORT INFORMATION Technical Information Report Type of Drainage Review Full / Targeted / (circle): Large Site Date (include revision April 2021 dates): Date of Final: Site Improvement Plan (Engr. Plans) Type (circle one): Full / Modified / Small Site Date (include revision April 2021 dates): Date of Final: MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page B-2 of 6 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx • Part 6 ADJUSTMENT APPROVALS Type (circle one): Standard / Complex / Preapplication / Experimental / Blanket Description: (include conditions in TIR Section 2) Date of Approval: Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: Completion Date: Describe: • Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan: Special District Overlays: Drainage Basin: Hylebos Creek Drainage Basin Stormwater Requirements: Core Req’ts #1 through #9, Special Req’ts #1 through #5. Part 9 ONSITE AND ADJACENT SENSITIVE AREAS River/Stream Hylebos Creek Lake Wetlands Wetland 1, 2 and 3 Closed Depression Floodplain Other Steep Slope Erosion Hazard Landslide Hazard Coal Mine Hazard Seismic Hazard Habitat Protection MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page B-3 of 6 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Part 10 SOILS Soil Type Alderwood (AgC) Alderwood (AgD) Kitsap (KpB) Slopes 8-15% 15-30% 2-8% Erosion Potential Slight ? Slight High Groundwater Table (within 5 feet) Other Sole Source Aquifer Seeps/Springs Additional Sheets Attached Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE Core 2 – Offsite Analysis Sensitive/Critical Areas SEPA Other LIMITATION / SITE CONSTRAINT West Hylebos Creek, wetlands onsite Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: TDA #1 Code Requirements (all 8 apply) Discharge at Natural Location Number of Natural Discharge Locations: 1 Offsite Analysis: Level 1 / 2 / 3 dated: April 2021 MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page B-4 of 6 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Flow Control (incl. facility summary sheet) Level 1 / 2 / 3 or Exemption Number Small Site BMPs Conveyance System Spill containment located at: N/A Erosion and Sediment Control ESC Site Supervisor: TBD Contact Phone: TBD After Hours Phone: TBD Maintenance and Operation Responsibility: Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Water Quality (include facility summary sheet) Type: Basic / Sens. Lake / Enhanced Basic / Bog or Exemption No. Landscape Management Plan: Yes / No Special Requirements (as applicable) Area Specific Drainage Requirements Type: CDA / SDO / MDP / BP / LMP / Shared Fac. / None Name: Floodplain/Floodway Delineation Type: Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): N/A Datum: N/A Flood Protection Facilities: Describe: N/A Source Control (comm./industrial land use) Describe land use: Commercial Describe any structural controls: None Oil Control High-use Site: Yes / No Treatment BMP: Maintenance Agreement: Yes / No With Whom? Other Drainage Structures Describe: Conveyance system catch basins and pipes conveying runoff to a media treatment device prior to discharge through a gravel filled dispersal trench. MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page B-5 of 6 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION Clearing Limits Cover Measures Perimeter Protection Traffic Area Stabilization Sediment Retention Surface Water Collection Dewatering Control Dust Control Flow Control MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION Stabilize Exposed Surfaces Remove and Restore Temporary ESC Facilities Clean and Remove All Silt and Debris, Ensure Operation of Permanent Facilities Flag Limits of SAO and open space preservation areas Other: Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Type/Description Water Quality Type/Description Detention Infiltration Regional Facility Shared Facility Flow Control BMPs Other Full Dispersion Permeable Pavement Biofiltration Wetpool Media Filtration Oil Control Spill Control Flow Control BMPs Other BioPod (enhanced) Permeable Pavement Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS Drainage Easement Covenant Native Growth Protection Easement Tract Other Cast in Place Vault Retaining Wall Rockery > 4’ High Structural on Steep Slope Other: MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page B-6 of 6 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. Signed/Date MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page C-1 of 1 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Appendix C - Conveyance Calculations 2019 INLET SPACING - CURB AND GUTTER SPREADSHEET (ENGLISH UNITS)Tc = 5.00Project Name: Cemetery RoadC = 0.90Project #: PTOI 23I = 2.91S.R.:m= 6.93Designed By: KXMUn= 0.54Date: 2/18/2020 Structure IDStationDistance (ft)Width (ft)Area (ft2)D Q cfs (cfs)S Q (cfs)Slope L (ft/ft)Super T (ft/ft) Grate Type HM Figure 5-11GRATE WIDTH (ft)GRATE LENGTH (ft)Roadway Classification Enter Requested Information Allowable Spread PolicyDriving Lane Width (ft)Shoulder Width (ft)Allowable Zd (ft)Calculated Zd (ft)Depth of Flow at Face of Curb d (inches)Manning's n for Street and Pavement GutterVelocity fo Gutter Flow (ft/sec)Ratio of Frontal Flow to Total Gutter Flow EoSplash-Over Velocity Vo (ft/sec)Ratio of Frontal Flow Intercepted to Full Frontal Flow RfRatio of Side Flow Intercepted to Total Side Flow RsEffiency of Grate EQi (cfs)Qbp (cfs)Zd Check Qbp CheckComments (L/R)----- 19+00.00 ------------------- ------------- ------------- ------------- ------------- ------------- ------------- ------------- ---------------------------------------------------------------------------------------------------------------- ------------- ------------- ------------- ------------- ------------- ------------- ------------- ------------- ------------- ------------- ------------- ------------- ------------- ------------- ------------- ------------- ------------- -------------718+90.0010.0024.000.01 0.010.103 0.020Standard Plan B-30.30-03 Rectangular Vaned Grate1.67 2.00 Collector and Local Streets Enter Speed (mph) ---------------> 15 Shoulder + 1/2 Driving Lane 12.00 0.00 6.00 0.95 0.23 0.016 1.57 1.00 4.60 1.00 0.23 1.00 0.01 0.00Zd Allowable > Zd Design616+31.00259.0024.000.37 0.370.103 0.020Standard Plan B-30.30-03 Rectangular Vaned Grate1.67 2.00 Collector and Local Streets Enter Speed (mph) ---------------> 15 Shoulder + 1/2 Driving Lane 12.00 0.00 6.00 3.23 0.78 0.016 3.56 0.86 4.60 1.00 0.06 0.87 0.32 0.05Zd Allowable > Zd Design515+00.00131.0024.000.19 0.240.050 0.020Standard Plan B-30.30-03 Rectangular Vaned Grate1.67 2.00 Collector and Local Streets Enter Speed (mph) ---------------> 15 Shoulder + 1/2 Driving Lane 12.00 0.00 6.00 3.13 0.75 0.016 2.43 0.87 4.60 1.00 0.12 0.88 0.21 0.03Zd Allowable > Zd Design414+00.00100.0024.000.14 0.170.050 0.020Standard Plan B-30.30-03 Rectangular Vaned Grate1.67 2.00 Collector and Local Streets Enter Speed (mph) ---------------> 15 Shoulder + 1/2 Driving Lane 12.00 0.00 6.00 2.77 0.66 0.016 2.23 0.92 4.60 1.00 0.13 0.93 0.16 0.01Zd Allowable > Zd Design312+44.00156.0024.000.23 0.240.150 0.020Standard Plan B-30.30-03 Rectangular Vaned Grate1.67 2.00 Collector and Local Streets Enter Speed (mph) ---------------> 15 Shoulder + 1/2 Driving Lane 12.00 0.00 6.00 2.54 0.61 0.016 3.65 0.94 4.60 1.00 0.06 0.95 0.22 0.01Zd Allowable > Zd Design211+77.0067.0024.000.10 0.110.150 0.020Standard Plan B-30.30-03 Rectangular Vaned Grate1.67 2.00 Collector and Local Streets Enter Speed (mph) ---------------> 15 Shoulder + 1/2 Driving Lane 12.00 0.00 6.00 1.90 0.46 0.016 3.01 1.00 4.60 1.00 0.08 1.00 0.11 0.00Zd Allowable > Zd DesignQbp < 0.1 CFS Fill in the data for the grey shaded areas onlyV6.2 Revised 9/13/2019 MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page D-1 of 10 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Appendix D - WWHM Calculations MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page D-2 of 10 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: Wetland 1 Input Volume Site Name: Site Address: City : Report Date: 4/8/2021 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 Precip Scale: 1.00 Version Date: 2019/09/13 Version : 4.2.17 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Mod 6.5 SAT, Forest, Mod .68 Pervious Total 7.18 Impervious Land Use acre Impervious Total 0 Basin Total 7.18 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : Basin 1 Bypass: No GroundWater: No MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page D-3 of 10 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Pervious Land Use acre C, Forest, Mod 6.03 SAT, Forest, Mod .68 Pervious Total 6.71 Impervious Land Use acre ROADS MOD 0.15 Impervious Total 0.15 Basin Total 6.86 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Wetlands Input Volume Average Annual Volume (acft) Series 1: 501 POC 1 Predeveloped flow Series 2: 801 POC 1 Mitigated flow Month Series 1 Series 2 Percent Pass/Fail Jan 2.1546 2.0758 96.3 Pass Feb 1.7721 1.6982 95.8 Pass Mar 1.5422 1.4772 95.8 Pass Apr 1.0021 0.9588 95.7 Pass May 0.5828 0.5575 95.7 Pass Jun 0.4200 0.4029 95.9 Pass Jul 0.3297 0.3123 94.7 Pass Aug 0.2624 0.2530 96.4 Pass Sep 0.2176 0.2170 99.7 Pass Oct 0.2571 0.2748 106.9 Pass Nov 0.8114 0.8257 101.8 Pass Dec 1.6833 1.6374 97.3 Pass Day Series 1 Series 2 Percent Pass/Fail Jan1 0.0662 0.0647 97.8 Pass 2 0.0670 0.0642 95.7 Pass 3 0.0622 0.0602 96.8 Pass 4 0.0702 0.0681 97.0 Pass 5 0.0731 0.0704 96.2 Pass 6 0.0762 0.0738 96.9 Pass 7 0.0710 0.0681 95.9 Pass 8 0.0703 0.0677 96.3 Pass 9 0.0626 0.0602 96.2 Pass 10 0.0587 0.0565 96.2 Pass 11 0.0632 0.0608 96.3 Pass 12 0.0645 0.0626 97.1 Pass 13 0.0751 0.0730 97.1 Pass MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page D-4 of 10 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx 14 0.0782 0.0751 96.0 Pass 15 0.0718 0.0689 96.0 Pass 16 0.0723 0.0694 96.1 Pass 17 0.0705 0.0680 96.5 Pass 18 0.0784 0.0753 96.1 Pass 19 0.0769 0.0738 96.0 Pass 20 0.0717 0.0688 95.9 Pass 21 0.0660 0.0634 96.1 Pass 22 0.0690 0.0671 97.2 Pass 23 0.0769 0.0742 96.5 Pass 24 0.0731 0.0699 95.5 Pass 25 0.0657 0.0629 95.7 Pass 26 0.0659 0.0632 95.8 Pass 27 0.0655 0.0629 95.9 Pass 28 0.0680 0.0657 96.5 Pass 29 0.0738 0.0709 96.0 Pass 30 0.0715 0.0690 96.6 Pass 31 0.0721 0.0689 95.6 Pass Feb1 0.0667 0.0638 95.7 Pass 2 0.0615 0.0586 95.4 Pass 3 0.0613 0.0585 95.5 Pass 4 0.0554 0.0527 95.3 Pass 5 0.0582 0.0561 96.4 Pass 6 0.0627 0.0601 95.9 Pass 7 0.0730 0.0704 96.5 Pass 8 0.0750 0.0715 95.4 Pass 9 0.0630 0.0601 95.3 Pass 10 0.0554 0.0530 95.6 Pass 11 0.0590 0.0570 96.6 Pass 12 0.0609 0.0583 95.8 Pass 13 0.0564 0.0541 95.9 Pass 14 0.0594 0.0572 96.4 Pass 15 0.0635 0.0614 96.6 Pass 16 0.0651 0.0624 96.0 Pass 17 0.0632 0.0610 96.5 Pass 18 0.0737 0.0709 96.2 Pass 19 0.0701 0.0666 95.0 Pass 20 0.0635 0.0607 95.6 Pass 21 0.0598 0.0571 95.4 Pass 22 0.0577 0.0553 95.8 Pass 23 0.0615 0.0591 96.0 Pass 24 0.0599 0.0574 95.8 Pass 25 0.0567 0.0541 95.5 Pass 26 0.0603 0.0578 95.9 Pass 27 0.0601 0.0576 95.9 Pass 28 0.0649 0.0618 95.2 Pass 29 0.0541 0.0518 95.8 Pass Mar1 0.0531 0.0508 95.8 Pass 2 0.0582 0.0563 96.7 Pass 3 0.0596 0.0570 95.6 Pass 4 0.0631 0.0605 96.0 Pass 5 0.0555 0.0525 94.7 Pass 6 0.0512 0.0488 95.3 Pass 7 0.0481 0.0463 96.4 Pass 8 0.0528 0.0510 96.5 Pass 9 0.0545 0.0523 95.9 Pass 10 0.0545 0.0525 96.3 Pass MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page D-5 of 10 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx 11 0.0596 0.0574 96.4 Pass 12 0.0558 0.0531 95.2 Pass 13 0.0520 0.0497 95.6 Pass 14 0.0529 0.0508 96.0 Pass 15 0.0501 0.0479 95.6 Pass 16 0.0514 0.0490 95.4 Pass 17 0.0502 0.0482 96.1 Pass 18 0.0492 0.0468 95.1 Pass 19 0.0448 0.0427 95.3 Pass 20 0.0415 0.0394 94.9 Pass 21 0.0449 0.0434 96.7 Pass 22 0.0483 0.0465 96.4 Pass 23 0.0471 0.0453 96.1 Pass 24 0.0460 0.0438 95.3 Pass 25 0.0423 0.0404 95.6 Pass 26 0.0411 0.0393 95.5 Pass 27 0.0394 0.0378 95.8 Pass 28 0.0404 0.0388 96.1 Pass 29 0.0411 0.0394 95.7 Pass 30 0.0392 0.0374 95.4 Pass 31 0.0380 0.0363 95.6 Pass Apr1 0.0358 0.0343 95.8 Pass 2 0.0362 0.0347 95.9 Pass 3 0.0428 0.0413 96.5 Pass 4 0.0462 0.0441 95.4 Pass 5 0.0418 0.0399 95.3 Pass 6 0.0371 0.0351 94.8 Pass 7 0.0362 0.0348 96.0 Pass 8 0.0384 0.0369 96.1 Pass 9 0.0357 0.0340 95.1 Pass 10 0.0335 0.0322 95.9 Pass 11 0.0327 0.0314 95.8 Pass 12 0.0340 0.0328 96.5 Pass 13 0.0330 0.0316 95.7 Pass 14 0.0315 0.0302 95.6 Pass 15 0.0345 0.0333 96.4 Pass 16 0.0361 0.0344 95.3 Pass 17 0.0308 0.0291 94.6 Pass 18 0.0333 0.0325 97.8 Pass 19 0.0360 0.0341 94.6 Pass 20 0.0304 0.0287 94.4 Pass 21 0.0292 0.0281 96.1 Pass 22 0.0345 0.0331 96.0 Pass 23 0.0305 0.0290 95.1 Pass 24 0.0277 0.0262 94.8 Pass 25 0.0255 0.0241 94.6 Pass 26 0.0250 0.0241 96.7 Pass 27 0.0245 0.0233 95.3 Pass 28 0.0249 0.0241 96.6 Pass 29 0.0264 0.0253 96.0 Pass 30 0.0259 0.0249 96.0 Pass May1 0.0244 0.0233 95.2 Pass 2 0.0229 0.0217 94.8 Pass 3 0.0228 0.0218 95.6 Pass 4 0.0229 0.0218 95.4 Pass 5 0.0226 0.0216 95.7 Pass 6 0.0216 0.0205 95.0 Pass MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page D-6 of 10 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx 7 0.0202 0.0192 94.9 Pass 8 0.0197 0.0187 95.0 Pass 9 0.0195 0.0186 95.3 Pass 10 0.0197 0.0189 96.1 Pass 11 0.0188 0.0178 95.0 Pass 12 0.0193 0.0183 95.1 Pass 13 0.0189 0.0182 96.3 Pass 14 0.0184 0.0176 95.5 Pass 15 0.0181 0.0172 95.2 Pass 16 0.0175 0.0167 95.4 Pass 17 0.0173 0.0166 95.9 Pass 18 0.0177 0.0171 96.6 Pass 19 0.0177 0.0168 95.0 Pass 20 0.0170 0.0161 94.8 Pass 21 0.0169 0.0160 94.7 Pass 22 0.0166 0.0159 95.9 Pass 23 0.0162 0.0156 96.1 Pass 24 0.0159 0.0151 94.9 Pass 25 0.0157 0.0152 97.4 Pass 26 0.0156 0.0150 96.1 Pass 27 0.0155 0.0149 96.1 Pass 28 0.0157 0.0153 97.6 Pass 29 0.0163 0.0158 97.1 Pass 30 0.0158 0.0154 97.0 Pass 31 0.0155 0.0150 96.6 Pass Jun1 0.0159 0.0152 95.4 Pass 2 0.0159 0.0155 97.1 Pass 3 0.0157 0.0152 97.0 Pass 4 0.0151 0.0144 95.4 Pass 5 0.0153 0.0149 97.4 Pass 6 0.0158 0.0152 96.3 Pass 7 0.0153 0.0147 96.0 Pass 8 0.0154 0.0149 96.4 Pass 9 0.0158 0.0152 96.2 Pass 10 0.0149 0.0144 96.8 Pass 11 0.0145 0.0140 96.3 Pass 12 0.0141 0.0133 94.3 Pass 13 0.0138 0.0130 94.4 Pass 14 0.0136 0.0129 95.2 Pass 15 0.0136 0.0130 95.4 Pass 16 0.0137 0.0132 96.8 Pass 17 0.0136 0.0128 94.4 Pass 18 0.0133 0.0126 94.7 Pass 19 0.0131 0.0126 96.0 Pass 20 0.0131 0.0126 95.8 Pass 21 0.0130 0.0123 94.9 Pass 22 0.0129 0.0123 95.3 Pass 23 0.0130 0.0131 100.5 Pass 24 0.0128 0.0122 95.0 Pass 25 0.0125 0.0119 94.8 Pass 26 0.0124 0.0118 95.0 Pass 27 0.0123 0.0117 95.9 Pass 28 0.0122 0.0116 95.4 Pass 29 0.0121 0.0116 95.9 Pass 30 0.0120 0.0116 96.0 Pass Jul1 0.0119 0.0113 95.2 Pass 2 0.0118 0.0112 95.0 Pass MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page D-7 of 10 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx 3 0.0116 0.0110 94.4 Pass 4 0.0116 0.0110 95.6 Pass 5 0.0114 0.0108 94.0 Pass 6 0.0113 0.0108 95.3 Pass 7 0.0113 0.0108 95.5 Pass 8 0.0112 0.0108 96.3 Pass 9 0.0111 0.0106 95.1 Pass 10 0.0110 0.0103 93.9 Pass 11 0.0110 0.0105 96.2 Pass 12 0.0109 0.0104 95.3 Pass 13 0.0108 0.0103 95.3 Pass 14 0.0107 0.0100 93.3 Pass 15 0.0106 0.0104 97.8 Pass 16 0.0106 0.0100 94.2 Pass 17 0.0105 0.0098 93.8 Pass 18 0.0104 0.0098 94.6 Pass 19 0.0103 0.0097 94.2 Pass 20 0.0102 0.0096 93.7 Pass 21 0.0101 0.0096 94.5 Pass 22 0.0100 0.0094 93.9 Pass 23 0.0099 0.0093 93.6 Pass 24 0.0098 0.0092 93.8 Pass 25 0.0098 0.0095 96.6 Pass 26 0.0097 0.0091 94.0 Pass 27 0.0096 0.0090 93.9 Pass 28 0.0095 0.0089 93.3 Pass 29 0.0095 0.0089 93.6 Pass 30 0.0094 0.0088 93.5 Pass 31 0.0093 0.0088 94.6 Pass Aug1 0.0093 0.0088 95.5 Pass 2 0.0092 0.0089 95.8 Pass 3 0.0092 0.0086 94.3 Pass 4 0.0091 0.0085 93.4 Pass 5 0.0090 0.0087 96.5 Pass 6 0.0089 0.0086 96.7 Pass 7 0.0089 0.0083 93.4 Pass 8 0.0088 0.0085 96.2 Pass 9 0.0087 0.0082 93.6 Pass 10 0.0087 0.0082 94.4 Pass 11 0.0086 0.0081 94.3 Pass 12 0.0086 0.0080 93.8 Pass 13 0.0085 0.0083 98.0 Pass 14 0.0085 0.0083 98.4 Pass 15 0.0084 0.0080 94.8 Pass 16 0.0084 0.0080 95.6 Pass 17 0.0083 0.0082 98.6 Pass 18 0.0082 0.0081 97.7 Pass 19 0.0082 0.0078 94.9 Pass 20 0.0081 0.0080 97.7 Pass 21 0.0081 0.0081 99.4 Pass 22 0.0081 0.0083 103.0 Pass 23 0.0081 0.0080 99.4 Pass 24 0.0080 0.0078 97.1 Pass 25 0.0080 0.0079 98.4 Pass 26 0.0079 0.0078 98.5 Pass 27 0.0079 0.0076 96.7 Pass 28 0.0078 0.0077 98.5 Pass MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page D-8 of 10 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx 29 0.0078 0.0075 95.5 Pass 30 0.0078 0.0075 96.1 Pass 31 0.0077 0.0075 97.7 Pass Sep1 0.0077 0.0075 98.1 Pass 2 0.0076 0.0074 96.9 Pass 3 0.0076 0.0075 99.1 Pass 4 0.0075 0.0072 96.0 Pass 5 0.0075 0.0074 98.9 Pass 6 0.0075 0.0070 94.2 Pass 7 0.0074 0.0073 98.8 Pass 8 0.0074 0.0071 96.4 Pass 9 0.0074 0.0074 100.8 Pass 10 0.0073 0.0071 97.3 Pass 11 0.0073 0.0069 94.8 Pass 12 0.0072 0.0070 96.2 Pass 13 0.0072 0.0073 101.2 Pass 14 0.0072 0.0070 97.5 Pass 15 0.0071 0.0071 99.1 Pass 16 0.0072 0.0079 110.6 Pass 17 0.0071 0.0071 100.0 Pass 18 0.0071 0.0073 102.1 Pass 19 0.0071 0.0071 100.8 Pass 20 0.0071 0.0070 99.0 Pass 21 0.0071 0.0076 107.1 Pass 22 0.0073 0.0074 100.7 Pass 23 0.0072 0.0072 100.8 Pass 24 0.0071 0.0071 100.6 Pass 25 0.0070 0.0071 100.8 Pass 26 0.0070 0.0071 101.7 Pass 27 0.0069 0.0071 101.8 Pass 28 0.0069 0.0068 99.1 Pass 29 0.0069 0.0073 105.3 Pass 30 0.0068 0.0068 99.7 Pass Oct1 0.0068 0.0068 100.6 Pass 2 0.0068 0.0071 104.5 Pass 3 0.0068 0.0074 108.5 Pass 4 0.0068 0.0070 103.4 Pass 5 0.0105 0.0112 106.4 Pass 6 0.0106 0.0105 99.1 Pass 7 0.0090 0.0099 110.6 Pass 8 0.0082 0.0091 110.1 Pass 9 0.0079 0.0085 108.6 Pass 10 0.0074 0.0074 100.0 Pass 11 0.0071 0.0073 102.6 Pass 12 0.0071 0.0073 103.8 Pass 13 0.0069 0.0073 105.2 Pass 14 0.0069 0.0071 103.1 Pass 15 0.0068 0.0072 105.0 Pass 16 0.0070 0.0078 112.1 Pass 17 0.0071 0.0077 107.8 Pass 18 0.0073 0.0082 113.0 Pass 19 0.0100 0.0118 118.0 Pass 20 0.0136 0.0141 103.5 Pass 21 0.0106 0.0112 105.3 Pass 22 0.0091 0.0095 104.6 Pass 23 0.0082 0.0088 107.5 Pass 24 0.0078 0.0086 110.0 Pass MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page D-9 of 10 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx 25 0.0078 0.0088 112.2 Pass 26 0.0079 0.0092 116.0 Pass 27 0.0080 0.0090 111.8 Pass 28 0.0094 0.0100 107.3 Pass 29 0.0109 0.0111 102.3 Pass 30 0.0099 0.0109 110.6 Pass 31 0.0098 0.0106 108.3 Pass Nov1 0.0106 0.0118 111.7 Pass 2 0.0122 0.0140 114.5 Pass 3 0.0119 0.0135 113.8 Pass 4 0.0109 0.0115 105.7 Pass 5 0.0153 0.0166 108.2 Pass 6 0.0169 0.0174 103.1 Pass 7 0.0144 0.0150 104.5 Pass 8 0.0151 0.0165 109.3 Pass 9 0.0175 0.0188 107.4 Pass 10 0.0203 0.0220 108.5 Pass 11 0.0219 0.0231 105.1 Pass 12 0.0215 0.0228 105.7 Pass 13 0.0232 0.0237 102.1 Pass 14 0.0217 0.0219 101.1 Pass 15 0.0204 0.0213 104.7 Pass 16 0.0209 0.0217 104.1 Pass 17 0.0243 0.0245 101.1 Pass 18 0.0316 0.0327 103.6 Pass 19 0.0387 0.0389 100.7 Pass 20 0.0382 0.0376 98.4 Pass 21 0.0341 0.0337 98.9 Pass 22 0.0356 0.0364 102.3 Pass 23 0.0525 0.0522 99.3 Pass 24 0.0554 0.0548 99.0 Pass 25 0.0500 0.0488 97.6 Pass 26 0.0445 0.0434 97.5 Pass 27 0.0378 0.0370 97.9 Pass 28 0.0398 0.0392 98.5 Pass 29 0.0445 0.0442 99.3 Pass 30 0.0423 0.0418 98.9 Pass Dec1 0.0430 0.0426 99.0 Pass 2 0.0581 0.0574 98.9 Pass 3 0.0562 0.0540 96.1 Pass 4 0.0478 0.0471 98.4 Pass 5 0.0478 0.0464 97.2 Pass 6 0.0441 0.0428 97.1 Pass 7 0.0433 0.0423 97.6 Pass 8 0.0447 0.0440 98.4 Pass 9 0.0489 0.0483 98.7 Pass 10 0.0518 0.0508 98.0 Pass 11 0.0541 0.0529 97.8 Pass 12 0.0550 0.0538 97.8 Pass 13 0.0569 0.0556 97.7 Pass 14 0.0689 0.0670 97.3 Pass 15 0.0620 0.0600 96.7 Pass 16 0.0552 0.0532 96.3 Pass 17 0.0511 0.0494 96.6 Pass 18 0.0481 0.0468 97.2 Pass 19 0.0553 0.0541 97.9 Pass 20 0.0565 0.0549 97.1 Pass MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page D-10 of 10 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx 21 0.0539 0.0521 96.7 Pass 22 0.0545 0.0529 97.0 Pass 23 0.0529 0.0510 96.4 Pass 24 0.0516 0.0502 97.1 Pass 25 0.0610 0.0595 97.5 Pass 26 0.0699 0.0674 96.5 Pass 27 0.0590 0.0563 95.4 Pass 28 0.0564 0.0552 97.8 Pass 29 0.0714 0.0690 96.5 Pass 30 0.0615 0.0588 95.7 Pass 31 0.0591 0.0570 96.4 Pass ___________________________________________________________________ WWHM2012 PROJECT REPORT - Permeable Pavement ___________________________________________________________________ Project Name: Permeable Pavement Site Name: Site Address: City : Report Date: 4/7/2021 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 Precip Scale: 1.00 Version Date: 2019/09/13 Version : 4.2.17 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ MITIGATED LAND USE Name : Permeable Pavement 1 Pavement Area: 0.2677 ft. Pavement Length: 530.00 ft. Pavement Width: 22.00 ft. Pavement slope 1: 0.023 To 1 Pavement thickness: 0.33 Pour Space of Pavement: 0.15 Material thickness of second layer: 0.33 Pour Space of material for second layer: 0.4 Material thickness of third layer: 0.75 Pour Space of material for third layer: 0.4 Infiltration On Infiltration rate: 1.26 Infiltration safety factor: 1 Total Volume Infiltrated (ac-ft.): 39.353 Total Volume Through Riser (ac-ft.): 0 Total Volume Through Facility (ac-ft.): 39.353 Percent Infiltrated: 100 Total Precip Applied to Facility: 0 Total Evap From Facility: 2.676 Element Flows To: Outlet 1 Outlet 2 ___________________________________________________________________ Permeable Pavement Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.267 0.000 0.000 0.000 0.0157 0.267 0.001 0.000 0.340 0.0313 0.268 0.003 0.000 0.340 0.0470 0.268 0.005 0.000 0.340 0.0627 0.268 0.006 0.000 0.340 0.0783 0.268 0.008 0.000 0.340 0.0940 0.268 0.010 0.000 0.340 0.1097 0.268 0.011 0.000 0.340 0.1253 0.269 0.013 0.000 0.340 0.1410 0.269 0.015 0.000 0.340 0.1567 0.269 0.016 0.000 0.340 0.1723 0.269 0.018 0.000 0.340 0.1880 0.269 0.020 0.000 0.340 0.2037 0.270 0.021 0.000 0.340 0.2193 0.270 0.023 0.000 0.340 0.2350 0.270 0.025 0.000 0.340 0.2507 0.270 0.027 0.000 0.340 0.2663 0.270 0.028 0.000 0.340 0.2820 0.270 0.030 0.000 0.340 0.2977 0.271 0.032 0.000 0.340 0.3133 0.271 0.033 0.000 0.340 0.3290 0.271 0.035 0.000 0.340 0.3447 0.271 0.037 0.000 0.340 0.3603 0.271 0.038 0.000 0.340 0.3760 0.272 0.040 0.000 0.340 0.3917 0.272 0.042 0.000 0.340 0.4073 0.272 0.044 0.000 0.340 0.4230 0.272 0.045 0.000 0.340 0.4387 0.272 0.047 0.000 0.340 0.4543 0.272 0.049 0.000 0.340 0.4700 0.273 0.050 0.000 0.340 0.4857 0.273 0.052 0.000 0.340 0.5013 0.273 0.054 0.000 0.340 0.5170 0.273 0.056 0.000 0.340 0.5327 0.273 0.057 0.000 0.340 0.5483 0.274 0.059 0.000 0.340 0.5640 0.274 0.061 0.000 0.340 0.5797 0.274 0.062 0.000 0.340 0.5953 0.274 0.064 0.000 0.340 0.6110 0.274 0.066 0.000 0.340 0.6267 0.274 0.068 0.000 0.340 0.6423 0.275 0.069 0.000 0.340 0.6580 0.275 0.071 0.000 0.340 0.6737 0.275 0.073 0.000 0.340 0.6893 0.275 0.074 0.000 0.340 0.7050 0.275 0.076 0.000 0.340 0.7207 0.276 0.078 0.000 0.340 0.7363 0.276 0.080 0.000 0.340 0.7520 0.276 0.081 0.000 0.340 0.7677 0.276 0.083 0.000 0.340 0.7833 0.276 0.085 0.000 0.340 0.7990 0.276 0.087 0.000 0.340 0.8147 0.277 0.088 0.000 0.340 0.8303 0.277 0.090 0.000 0.340 0.8460 0.277 0.092 0.000 0.340 0.8617 0.277 0.094 0.000 0.340 0.8773 0.277 0.095 0.000 0.340 0.8930 0.278 0.097 0.000 0.340 0.9087 0.278 0.099 0.000 0.340 0.9243 0.278 0.100 0.000 0.340 0.9400 0.278 0.102 0.000 0.340 0.9557 0.278 0.104 0.000 0.340 0.9713 0.278 0.106 0.000 0.340 0.9870 0.279 0.107 0.000 0.340 1.0027 0.279 0.109 0.000 0.340 1.0183 0.279 0.111 0.000 0.340 1.0340 0.279 0.113 0.000 0.340 1.0497 0.279 0.114 0.000 0.340 1.0653 0.280 0.116 0.000 0.340 1.0810 0.280 0.117 0.000 0.340 1.0967 0.280 0.118 0.000 0.340 1.1123 0.280 0.118 0.000 0.340 1.1280 0.280 0.119 0.000 0.340 1.1437 0.280 0.120 0.000 0.340 1.1593 0.281 0.120 0.000 0.340 1.1750 0.281 0.121 0.000 0.340 1.1907 0.281 0.122 0.000 0.340 1.2063 0.281 0.122 0.000 0.340 1.2220 0.281 0.123 0.000 0.340 1.2377 0.282 0.124 0.000 0.340 1.2533 0.282 0.124 0.000 0.340 1.2690 0.282 0.125 0.000 0.340 1.2847 0.282 0.125 0.000 0.340 1.3003 0.282 0.126 0.000 0.340 1.3160 0.282 0.127 0.000 0.340 1.3317 0.283 0.127 0.000 0.340 1.3473 0.283 0.128 0.000 0.340 1.3630 0.283 0.129 0.000 0.340 1.3787 0.283 0.129 0.000 0.340 1.3943 0.283 0.130 0.000 0.340 ___________________________________________________________________ Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0 5 year 0 10 year 0 25 year 0 50 year 0 100 year 0 MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page E-1 of 1 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Appendix E - Construction Stormwater Pollution Prevention Plan (C-SWPPP) MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page F-1 of 1 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Appendix F - Geotechnical Report South Sound Geotechnical Consulting P.O. Box 39500, Lakewood, WA 98496 (253) 973-0515 January 7, 2020 David Evans and Associates, Inc. 2106 Pacific Avenue, Suite 400 Tacoma, Washington 98402 Attention: Mr. Andrew Harris, P.E. Subject: Geotechnical Engineering Report Puyallup Tribal Cemetery Road Federal Way, Washington SSGC Project No. 19100 Mr. Harris, South Sound Geotechnical Consulting (SSGC) has completed a geotechnical assessment for the planned Cemetery Road extension along the 8th Avenue Road alignment in Federal Way (King County), Washington. Our services have been completed in general conformance with our proposal (P19045, dated May 23, 2019) and authorized per David Evans and Associates Subconsultant agreement. Our scope of services included completion of ten test pits and one infiltration test, laboratory testing, engineering analyses, and preparation of this report. PROJECT INFORMATION A new road is planned that would extend from the intersection of South 376th Street and 8th Avenue South to the south for access to the existing Puyallup Tribal cemetery. Overall length of the new road is on the order of 1,700 (+/-) feet. Cut and fill areas will be required to establish final road grades. SITE CONDITIONS Beginning at the southern end of 8th Avenue South (at the intersection with South 376th Street), the new alignment extends southwesterly approximately 400 feet along relatively flat ground. This portion of the alignment is covered with an existing grass trail and brush with some trees. The alignment then traverses forested west-facing sloping ground with inclinations of about 20 percent or shallower for an additional 400 (+/-) feet to a relatively level bench area extending another 300 (+/-) feet. The alignment continues down a southerly facing forested slope with inclinations of about 20 percent or less to a flatter lower area where the alignment ends. The southern portion of the alignment is in (or near) designated wetlands. SUBSURFACE CONDITIONS Subsurface conditions were characterized by completing ten test pits and one infiltration test on December 4, 2019. Approximate locations of the explorations are shown on Figure 1, Exploration Plan. No explorations were completed in the designated wetland areas near the southern end of the alignment. Geotechnical Engineering Report SSGC Cemetery Road King County, Washington SSGC Project No. 19100 January 7, 2020 2 A summary description of observed subgrade conditions is provided below. Logs of the test pits are provided in Appendix A. Soil Conditions Subgrade conditions north of the lower (southern) wetland were fairly uniform across the alignment (all test pits exclusive of test pit TP-8). A surface topsoil layer extended to between about 6 inches and 1 foot in the test pits. Native silty sand with occasional gravel and variable roots was below the surface and extended to depths ranging from about 1.5 to 4 feet. This soil was in a loose to medium dense condition. It is interpreted to represent weather native soil. Below this layer was silty sand with gravel in a medium dense to dense condition. This soil is interpreted to represent sandy glacial till and extended to the termination depth of the test pits, with the exception of test pit TP-8. Test pit TP-8 was located near the base of the steeper south-facing slope, above the wetlands. Minor debris (burnt wood and cans) was mixed with the topsoil layer to a depth of about 1.5 feet. Native soil consisting of sandy silt in a stiff condition was observed below the fill and extended to the termination depth of the test pit. Groundwater Conditions Groundwater was not observed in the test pits at the time of excavation. However, denser glacial till can form a barrier to vertical groundwater flow and create seasonal perched groundwater conditions. This results in mostly lateral flow through the upper weathered portion of till. In addition, the sandy silt observed in test pit TP-8 and presence of wetlands in the southern portion of the alignment suggests shallow groundwater levels should be anticipated in this area. Groundwater levels should be anticipated to vary throughout the year due to season al precipitation and on- and off-site drainage patterns. Geologic Setting Native soils over the higher elevated portions of the alignment are mapped as Alderwood gravelly sandy loam per the USDA Soil Conservation Service map of King County, Washington. Alderwood soils are reportedly formed in glacial till. Soils below the slopes in the wetland area are mapped as Kitsap silt loam, formed in glacial lake deposits. Both soils are generally considered impermeable to vertical groundwater flow. Soils in the test pits appeared to conform to the mapped soil types. GEOTECHNICAL DESIGN CONSIDERATIONS The planned road extension is considered feasible based on observed soil conditions in the test pits. Native soils can be used for support of new pavements. Limited infiltration in the upper till soils above the wetland area may be feasible for shallow infiltration facilities depending on final grades. Infiltration is not considered feasible in the silt soils in the lower portion of the align ment, near or in the wetland areas. Geotechnical Engineering Report SSGC Cemetery Road King County, Washington SSGC Project No. 19100 January 7, 2020 3 Recommendations presented in the following sections should be considered general and may require modifications when earthwork and grading occur. They are based upon the subsurface conditions observed in the test pits and may require modifications depending on final grades. It should be noted subsurface conditions across the site may 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 assess subgrade conditions at the time of construction. General Site Preparation Site grading and earthwork should include procedures to control surface water runoff. Grading without adequate drainage control measures may negatively impact site soils, resulting in increased export of impacted soil and import of fill materials, potentially increasing the cost of earthwork and subgrade preparation phases of the project. Site grading should include removal of topsoil, fill, or upper soils having roots with diameters over 2- inches. Subgrades should consist of firm native till soils following stripping in the alignment north of the wetland areas. In the lower southern portion of the alignment stripping depth should include removal of the upper silt to at least 2 feet below the design grade of the pavement section (base course and pavement). Although stripping depths are estimated to range from about 1 to 2 feet on average, they will vary and final stripping depths can only be determined at the time of construction. General Subgrade Preparation Subgrades in pavement areas should consist of firm native soils. We recommend exposed subgrades in pavement and shoulder areas where native till is present 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 achieving 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 cannot achieve this compaction level should be removed (over-excavated) and replaced with structural fill. Where native silt subgrades are present in the lower southern portion, we recommend proofrolling consist of a smooth drum compactor in static mode. Soft or excessively wet soils should be removed an additional 1 foot. 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. Geotechnical Engineering Report SSGC Cemetery Road King County, Washington SSGC Project No. 19100 January 7, 2020 4 Grading and Drainage Positive drainage should be provided during construction and maintained throughout the life of the development. Allowing surface water into cut or fill areas and utility trenches should be prevented. 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 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: Topsoil is not suitable for use as structural fill. Native silt in the lower southern portion is not considered suitable for structural fill. Native glacial till is considered suitable for use as structural fill provided it can also be moisture conditioned to within optimal ranges. Optimum moisture is considered within about +/- 2 percent of the moisture content required to achieve the maximum density per the ASTM D-1557 test method. If moisture content is higher or lower than optimum, soils would need to be dried or wetted prior to placement as structural fill. Note the use of glacial till is often seasonal dependent. This soil contains sufficient fines that make it moisture sensitive and difficult to properly compact outside of the drier summer months. Import Fill Materials: We recommend import structural fill placed during dry weather periods 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 (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 generally 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. It should be noted that 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. Geotechnical Engineering Report SSGC Cemetery Road King County, Washington SSGC Project No. 19100 January 7, 2020 5 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. Coarser granular soil with lower fines contents could potentially be placed in thicker lifts 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 (below structures and retaining walls) 95 % Upper 2 feet in pavement areas, slabs and sidewalks, and utility trenches 95 % Below 2 feet in pavement areas, slabs and sidewalks, and utility trenches 92 % 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 be 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 unusable, it may become necessary to import clean, granular soils to complete wet weather site work. Observed native soils contain enough fines (silt and clay) that they can become easily disturbed when wet. Geotechnical Engineering Report SSGC Cemetery Road King County, Washington SSGC Project No. 19100 January 7, 2020 6 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 late October through May) it may be necessary to take extra measures to protect subgrade soils. If earthwork takes place during freezing conditions, we recommend the exposed subgrade be allowed to thaw and be 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 inclinations. Permanent cut and fill slopes should have final inclinations of 2H:1V, or flatter. Grading for the alignment will require cuts and fills, especially in the sloped portions. Structural or embankment fill placed on slopes should be benched into firm (dense) native glacial till. Benches should be excavated level (or with a slight incline into the hillside). Benches should be a maximum of 2 feet high and wide enough to accommodate a conventional vibratory smooth-drum roller capable of compacting fill to at least 95 percent of the maximum dry density per the ASTM D 1557 test method. A geotechnical engineer and accredited testing material laboratory 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. Conventional Asphalt Pavement Sections Subgrades for conventional pavement areas should be prepared as described in the “Subgrade Preparation” and “Structural Fill” sections of this report. Subgrades below pavement sections should be graded or crowned to promote drainage and not allow for ponding of water beneath the section. If drainage is not provided and ponding occurs, subgrade soils could become saturated, lose strength, and result in premature distress or failure of the pavement. In addition, the pavement surfacing should also be graded to promote drainage and reduce the potential for ponding of water on the pavement surface. We recommend a separation geotextile fabric (such as Mirafi 160N, or equivalent) is used on native silt subgrade soils below planned pavement sections in the lower southern (wetland) areas. This fabric should be placed on the prepared subgrade prior to placement of granular pavement section fill. The purpose of the fabric is to maintain separation of the coarser section fill materials and the moisture sensitive finer grained native soils, which will reduce the risk of migration of the coarser fill into native soils. The fabric will improve the overall performance of the section over time. Geotechnical Engineering Report SSGC Cemetery Road King County, Washington SSGC Project No. 19100 January 7, 2020 7 Pavement section designs have been prepared and are based on AASHTO design guidelines and the following assumed design parameters:  30-year life span;  Estimated design life Equivalent Single Axle Loads (18 kips) of 50,000;  Estimated subgrade CBR of 6 (native soil);  Terminal serviceability of 2.0; and,  Level of reliability 85 percent. Minimum recommended pavement sections for conventional asphalt pavements are presented in Table 2. We should be notified if actual traffic (ESAL) loads will be greater than those assumed to verify or modify the pavement sections. Pavement sections in city right-of-ways should conform to City of Federal Way requirements for the designated road type. Table 2. Preliminary Pavement Sections Traffic Area Minimum Recommended Pavement Section Thickness (inches) Asphalt Concrete Surface1 Portland Cement Concrete Aggregate Base Course2 Subbase Aggregate3 Car Parking Areas 2 - 4 12 Road Section over Glacial Till Subgrade 3 - 6 12 Road Section over Native Silt Subgrade 3 - 6 24 1 1/2 –inch nominal aggregate hot-mix asphalt (HMA) per WSDOT 9-03.8(1) 2 Crushed Surfacing Base Course per WSDOT 9-03.9(3) 3 95% compacted native outwash subgrade or Gravel Borrow per WSDOT 9-03.14(1) or Crushed Surfacing Base Course WSDOT 9-03.9(3) over native silt Conventional Pavement Maintenance The performance and lifespan of pavements can be significantly impacted by future maintenance. The above pavement sections represent minimum recommended thicknesses and, as such, periodic maintenance should be completed. Proper maintenance will slow the rate of pavement deterioration, and will improve pavement performance and life. Preventive maintenance consists of both localized maintenance (crack and joint sealing and patching) and global maintenance (surface sealing). Added maintenance measures and reduced pavement life should be anticipated over the lifetime of pavements if any existing fill or topsoil is left in-place beneath pavement sections. Geotechnical Engineering Report SSGC Cemetery Road King County, Washington SSGC Project No. 19100 January 7, 2020 8 Infiltration Characteristics We understand infiltration facilities to assist in stormwater control will be used, if feasible. Assessment of infiltration potential in the upper weathered till was completed per the 2016 King County Surface Water Design Manual. One small-scale Pilot Infiltration Tests (PIT) was completed in the upper weathered glacial till. Approximate location of the test is shown on Figure 1. Result of the infiltration test is provided in Table 3. Table 3. Infiltration Rates Test Site and Depth Soil Type Field Infiltration Rate (in/hr) Corrected Infiltration Rate (in/hr) Correction Factors* (CFg/CFt/CFp) PIT-1, 2.5 ft Weathered Till 4.5 1.26 (0.7/0.5/0.8) *Correction Factors from the 2016 King County Surface Water Design Manual. The calculated and corrected infiltration rate is considered appropriate for the upper soils tested and is similar to rates in weathered till throughout the region. The soil profile along the alignment above the wetland area appeared fairly uniform. A long-term design rate of 1.25 in/hr is considered appropriate for the upper weathered till with the assigned correction factors. Infiltration is not considered feasible in the native silt observed near the wetland area. It should be noted infiltrated water will migrate down to denser till and then flow laterally. If cuts (grade lowering) over 3 feet of existing grades are planned, infiltration may not be feasible. Cation Exchange Capacity (CEC) and organic content tests were completed on a soil sample from the bottom of the infiltration test hole. Test results are summarized in the Table 4. Table 4. CEC and Organic Content Results Test Location, Sample Number CEC Results (milliequivalents) CEC Required* (milliequivalents) Organic Content Results (%) Organic Content Required* (%) PIT-1, S-1 4.1 ≥ 5 1.46 ≥1.0 * Per the 2016 King County Surface Water Design Manual. Organic content results satisfy county requirements at the PIT site. The CEC value was slightly lower than required levels, which is not uncommon for glacial till. Additional tests could be considered once Geotechnical Engineering Report SSGC Cemetery Road King County, Washington SSGC Project No. 19100 January 7, 2020 9 final infiltration facility locations have been established to assess treatment characteristics in those areas and the need for remedial measures. Critical Areas The alignment traverses ground with overall gentle slopes that are less than 15 percent and would not be classified as landslide hazard areas per Chapter 21A.06.680 of the King County Municipal Code (KCMC). Locally steeper slopes are present along two areas of the alignment with maximum slope inclinations on the order of 20 (+/-) percent. However, evidence of hillside seepage or a soil profile of permeable granular soil over impermeable soil was not observed on these slopes. Evidence of recent or historic slope movement was not observed. The trunks of mature fir and cedar trees on steeper slopes were generally straight. As such, site slopes are not considered landslide hazard areas. Construction of the road on site slopes should not adversely impact stability with proper construction techniques and drainage control. Site soils have a low to moderate potential for erosion. Construction on sloping ground will increase the potential for erosion and added erosion control measures may be necessary. 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 on this site. Additional erosion control measures may be necessary if earthwork is scheduled during the wet ter seasons. All erosion control provisions should be in compliance with City of Federal Way (or King County) regulations to reduce the risk of off-site transport of sediments. Exposed soils following all construction should be vegetated as soon as possible. Irrigation should not be allowed on or near site slopes. Temporary and permanent stormwater control measures should prevent concentrated flow onto site slopes. REPORT CONDITIONS This report has been prepared for the exclusive use of David Evans and Associates, and the Puyallup Tribe 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 sites, or due to the modifying effects of construction, or weather. 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. 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. N South Sound Geotechnical Consulting P.O. Box 39500 Lakewood, WA 98496 (253) 973-0515 Figure 1 – Exploration Plan Puyallup Tribe Cemetery Road King County, WA SSGC Project #19100 Approximate Test Pit Location PIT - 1 TP - 1 PIT - 1 Approximate Infiltration Test Location Scale: NTS Base map from drawing provided by David Evans and Associates, Inc.. TP-1 Legend TP-2 TP-3 PIT-1 TP-1 TP-4 TP-5 TP-6 TP-7 TP-8 TP-9 TP-10 Geotechnical Engineering Report SSGC NOA Parking Expansion 3424 Burwell Street Bremerton, Washington SSGC Project No. 19012 March 14, 2019 Appendix A Field Exploration Procedures and Test Pit Logs Geotechnical Engineering Report SSGC Cemetery Road King County, Washington SSGC Project No. 19100 January 7, 2020 A-1 Field Exploration Procedures Our field exploration for this project included ten test pits and one infiltration test completed on December 4, 2019. The approximate locations of the explorations are shown on Figure 1, Exploration Plan. Test pit locations were determined by pacing from site features. Ground surface elevations referenced on the logs were inferred from topographic information completed by David Evans and Associates. Test pit locations and elevations should be considered accurate only to the degree implied by the means and methods used. A private excavation contractor subcontracted to SSGC dug the test pits and infiltration test hole. Soil samples were collected and stored in moisture tight containers for further assessment and laboratory testing. Explorations were backfilled with excavated soils and tamped when completed. Please note backfill in the explorations may settle with time. Backfill material located in pavement or building 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: Cemetery Road SSGC Job # 19100 TEST PIT LOGS PAGE 1 OF 4 Location: Federal Way, WA TEST PIT LOGS FIGURE A-1 South Sound Geotechnical Consulting TP-1 TO TP-10 Logged by: THR Test Pit TP-1 Depth (feet) Material Description 0 – 0.5 0.5 – 1.5 1.5 – 4 Topsoil Silty SAND with occasional gravel and roots: Loose to medium dense, moist, brown. Silty SAND with gravel and occasional cobble: Medium dense, moist, grayish brown. (Sandy Glacial Till) Test pit completed at approximately feet on 12/4/19. Groundwater not observed at time of excavation. Approximate surface elevation: 154 feet Test Pit TP-2 Depth (feet) Material Description 0 – 0.5 0.5 – 2 2 - 5 Topsoil Silty SAND with occasional gravel: Medium dense, moist, brown. SAND with silt, gravel and occasional cobble: Medium dense to dense, moist, gray. (Sample S-1 @ 3.5 feet)(Sandy Glacial Till) Test pit completed at approximately 5 feet on 12/4/19. Groundwater not observed at time of excavation. Approximate surface elevation: 150 feet Test Pit TP-3 Depth (feet) Material Description 0 – 1 1 – 3.5 3.5 – 5 Topsoil Silty SAND with occasional gravel: Loose, damp, light brown. Silty SAND with gravel: Medium dense to dense, moist, gray. (Sandy Glacial Till) Test pit completed at approximately 5 feet on 12/4/19. Groundwater not observed at time of excavation. Approximate surface elevation: 140 feet Project: Cemetery Road SSGC Job # 19100 TEST PIT LOGS PAGE 2 OF 4 Location: Federal Way, WA TEST PIT LOGS FIGURE A-1 South Sound Geotechnical Consulting TP-1 TO TP-10 Logged by: THR Test Pit TP-4 Depth (feet) Material Description 0 – 1 1 – 3 3 – 4 4 – 5 Topsoil SAND with silt, roots, and occasional gravel: Loose, damp, light brown. Silty SAND with gravel and occasional cobble: Medium dense, moist, light brown. Silty SAND with gravel: Dense, moist, gray. (Sandy Glacial Till) Test pit completed at approximately 5 feet on 12/4/19. Groundwater not observed at time of excavation. Approximate surface elevation: 132 feet Test Pit TP-5 Depth (feet) Material Description 0 – 0.5 0.5 – 1.5 1.5 – 2.5 2.5 – 5 Topsoil Silty SAND with occasional gravel: Loose, moist, mottled orange-brown. Silty SAND with gravel and occasional cobble: Medium dense, moist, light brown. SAND with silt, gravel, cobbles and boulder: Medium dense to dense, moist, gray. (Sandy Glacial Till) Test pit completed at approximately 5 feet on 12/4/19. Groundwater not observed at time of excavation. Approximate surface elevation: 120 feet Project: Cemetery Road SSGC Job # 19100 TEST PIT LOGS PAGE 3 OF 4 Location: Federal Way, WA TEST PIT LOGS FIGURE A-1 South Sound Geotechnical Consulting TP-1 TO TP-10 Logged by: THR Test Pit TP-6 Depth (feet) Material Description 0 – 1 1 – 3 3 – 5 Topsoil Silty SAND with gravel: Loose, moist, brown. SAND with silt, gravel, and occasional cobble: Medium dense to dense, moist, gray. (Sandy Glacial Till) Test pit completed at approximately 5 feet on 12/4/19. Groundwater not observed at time of excavation. Approximate surface elevation: 116 feet Test Pit TP-7 Depth (feet) Material Description 0 – 0.5 0.5 – 3 3 – 4 Topsoil Silty SAND with occasional gravel: Loose, moist, grayish brown. SAND with silt, gravel, and occasional cobble: Medium dense to dense, moist, gray. (Sandy Glacial Till) Test pit completed at approximately 4 feet on 12/4/19. Groundwater not observed at time of excavation. Approximate surface elevation: 104 feet Test Pit TP-8 Depth (feet) Material Description 0 – 1.5 1.5 – 4 Fill over Topsoil Sandy SILT with occasional gravel: Stiff, moist, light brown. Test pit completed at approximately 4 feet on 12/4/19. Groundwater not observed at time of excavation. Approximate surface elevation: 54 feet Project: Cemetery Road SSGC Job # 19100 TEST PIT LOGS PAGE 4 OF 4 Location: Federal Way, WA TEST PIT LOGS FIGURE A-1 South Sound Geotechnical Consulting TP-1 TO TP-10 Logged by: THR Test Pit TP-9 Depth (feet) Material Description 0 – 1 1 – 2.5 2.5 – 4 Topsoil Silty SAND with occasional gravel: Loose to medium dense, moist, grayish brown. Silty SAND with gravel and occasional cobble: Dense to very dense, moist, gray. (Sandy Glacial Till) Test pit completed at approximately 4 feet on 12/4/19. Groundwater not observed at time of excavation. Approximate surface elevation: 110 feet Test Pit TP-10 Depth (feet) Material Description 0 – 1 1 – 3 3 – 5 Topsoil Sandy SILT with occasional gravel: Stiff, moist, light brown. Silty SAND with gravel and occasional cobble: Dense to very dense, moist, gray. (Sandy Glacial Till) Test pit completed at approximately 5 feet on 12/4/19. Groundwater not observed at time of excavation. Approximate surface elevation: 112 feet Geotechnical Engineering Report SSGC NOA Parking Expansion 3424 Burwell Street Bremerton, Washington SSGC Project No. 19012 March 14, 2019 Appendix B Laboratory Testing and Results Geotechnical Engineering Report SSGC Cemetery Road King County, Washington SSGC Project No. 19100 January 7, 2020 B-1 Laboratory Testing Cation Exchange Capacity (CEC) and organic content tests were completed by Northwest Agriculture Consultants of Kennewick, Washington on samples from the PIT test site. Results of the laboratory testing are included in this appendix. 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 1.46% 4.1 meq/100g Method ASTM D2974 EPA 9081 South Sound Geotechnical Consulting PO Box 39500 Lakewood, WA 98496 Report: 50142-1-1 Date: December 10, 2019 Project No: 19100 Project Name: Cemetery Road 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. MC# PTOI-0023 Preliminary Drainage Report | 50% Draft 4/8/2021 Cemetery Road Page G-1 of 1 P:\P\PTOI0023\0600INFO\0670Reports\Drainage Report\Draft\PTOI23 Drainage Report 50 Percent Draft.docx Appendix G - Ground Penetrating Radar Survey for the St. George Cemetery Ground Penetrating Radar Survey for the St. George Cemetery DRAFT Prepared for Momentum Civil Engineering Consultants 1145 Broadway, Suite 115 Tacoma, WA 98402 Prepared by Steve Hackenberger (Phd), Josh Allen (M.S), and Mackenzie Hughes (M.S) Central Washington Anthropological Survey Central Washington University, 400 East University Way Ellensburg, WA 98926-7523 DRAFT February 2021 Central Washington Anthropological Survey iii TABLE OF CONTENTS INTRODUCTION.............................................................................................................................. 5 Project Background .................................................................................................................... 7 RESEARCH METHODOLOGY ..................................................................................................... 9 RESULTS ......................................................................................................................................... 11 CONCLUSIONS AND RECOMMENDATIONS ......................................................................... 22 REFERENCES CITED ................................................................................................................... 23 LIST OF FIGURES FIGURE 1. PROJECT AREA. .................................................................................................................... 6 FIGURE 2. EXAMPLE OF GRID (GRID 1). VIEW: WEST. ........................................................................ 10 FIGURE 3. SEVEN EXAMPLE GRAVES FOR COMPARISON (NOT IN CURRENT PROJECT AREA, COMPARISON ONLY). ........................................................................................................................................ 11 FIGURE 4. PLAN VIEW MAP OF GRID 1. ............................................................................................... 12 FIGURE 5. GRID 1 GPR REFLECTIONS (TOP SLICE VIEW 20 CENTIMETERS DEEP) SHOW FILL UP TO 30 CENTIMETERS BELOW SURFACE AND ARE NOT CONSISTENT WITH INTACT OR REMENANT GRAVE FEATURES.................................................................................................................................... 13 FIGURE 6. GRID 1 GPR REFLECTIONS (TOP SLICE VIEW 60 CENTIMETERS DEEP) SHOW COBBLE/BOULDER DISTRIBUTION MOSTLY BETWEEN 80-100 CENTIMETERS BELOW SURFACE. ... 13 FIGURE 7. PLAN VIEW MAP OF GRID 2. ............................................................................................... 14 FIGURE 8. BOUNDARY BETWEEN GRID 1 AND GRID 2. VIEW: WEST. ................................................. 15 FIGURE 9. GRID 2 GPR REFLECTIONS (TOP SLICE VIEW 20 CENTIMETERS DEEP) SHOW SURFACE MOISTURE AND SILT FILL (BOTTOM LINE 3 VIEW). THE RED OVAL MARKS POSSIBLE METAL OBJECT. ....................................................................................................................................... 15 FIGURE 10. PLAN VIEW MAP OF GRID 3, NOTE THE SWATH AREA SHIFTED TO THE SOUTH. ................. 16 FIGURE 11. BOUNDARY BETWEEN GRID 3 AND GRID 4. VIEW: WEST. ............................................... 17 FIGURE 12. GRID 3 GPR REFLECTIONS (TOP SLICE VIEW 40 CENTIMETERS DEEP) SHOW COBBLE/BOULDER DISTRIBUTION PRIMARILY BETWEEN 50-100 CENTIMETERS BELOW THE SURFACE (BOTTOM LINE 4 VIEW). ............................................................................................... 17 FIGURE 13. CAST IRON LEG OR FENCE PART (LEFT) AND COFFIN IDENTIFICATION NUMBER PLATE (RIGHT) FOUND WITHIN GRID 3. .................................................................................................. 18 FIGURE 14. THE LOCATION (LEFT) AND DETAILS (RIGHT) OF AN OBELISK GRAVE MARKER FOUND AT THE BOUNDARY BETWEEN GRID 3 AND GRID 4. VIEW: SOUTHWEST. .......................................... 18 FIGURE 15. PLAN VIEW MAP OF GRID 4. ............................................................................................. 19 FIGURE 16. GRID 4 AREA, NOTE THE STONE GRAVE MARKER IN THE CENTER RIGHT. VIEW: EAST. ..... 20 FIGURE 17. GRID 4 GPR REFLECTIONS (TOP SLICE VIEW 40 CENTIMETERS DEEP) SHOW COBBLE/BOULDER DISTRIBUTION PRIMARILY BETWEEN 80-100 CENTIMETERS BELOW THE SURFACE (BOTTOM LINE 4 VIEW). ............................................................................................... 20 Central Washington Anthropological Survey iv FIGURE 18. GRID 4 PATH EXTENSION GPR REFLECTIONS (TOP SLICE VIEW 80 CENTIMETERS DEEP) SHOW COBBLE/BOULDER DISTRIBUTION PRIMARILY BETWEEN 80-100 CENTIMETERS BELOW THE SURFACE (BOTTOM LINE 4 VIEW). ............................................................................................... 21 FIGURE 19. TWO GRAVE MARKERS LOCATED WITHIN THE BOUNDARIES OF GRID 4. ........................... 21 Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 5 INTRODUCTION In December of 2020 Momentum Civil Engineering Consultants contracted with Central Washington Anthropological Survey (CWAS) to deploy Ground Penetrating Radar (GPR) as a non- destructive method of identifying possible features within the St. George Cemetery project area. This field work was an addendum to the original August 2020 project that involved the identification of subsurface features within eight grids on the South facing slope in the northeast portion of the project area. The addendum aims to identify if any subsurface features are present within the graded roadway to the southwest of the previous eight grid locations. Four grids were placed within the graded road way in an effort to identify additional grave features (Figure 1). Dr. Steven Hackenberger (Professor, CWU Dept. of Anthropology), Mackenzie Hughes, M.S. (Crew Chief), one student (Astra Miller), and one volunteer (Matthew Johnson, M.S.) conducted GPR survey within the Project Area (Figure 1). Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 6 Figure 1. Project Area. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 7 Project Background Father Hylebos established the “St. George's Industrial School for Indians,” with support from Miss Katharine Drexel, and the devotion of lay teacher, Esther Stevenson. The Bureau of Catholic Indian Missions in Washington DC helped support grants from a group of Franciscan Sisters from Philadelphia. The Sisters convened their first classes on October 26, 1888. Boarding school policy was total assimilation into dominant culture and students included Puyallup, Yakima, Tulalip, Muckleshoot, and others. As a working farm, and children learned trades: the Sisters taught the girls to cook, sew, and raise chickens, while the chaplain, Father De Decker, helped the boys learn to handle horses and cows, clear land, build fences, and plant and harvest crops. St. George’s School had an enrollment of about 60 pupils in 1913 and “thrived” into the 1920s but closed due to the Great Depression. Bishop Shaughnessy, facing debt, closed the school in 1936. The link contains a history written by Corinna Laughlin, Pastoral Assistant for Liturgy St. James Cathedral, Seattle. Archival records, known to Puyallup historians include records and correspondence at Marquette University and the Puyallup Tribal Museum (Marquette University 2020). Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 8 The St. George Cemetery Project Area The cemetery is associated with the St. George boarding school. The cemetery area includes a gentle sloping, South facing slope and possibly includes an unpaved access roadway adjacent to the southwest. The soil consists of fine silt with cobble. Some cobble is no doubt naturally occurring but large cobbles and boulders also appear to have been used in protecting graves. The slope is forested and the project area includes several mature cedar. According to personal accounts, the cemetery has been the resting place for both staff and students from the St. George school. An unknown number of burials were placed in the cemetery and an unknown number of burials were relocated. Several full-size graves remain open to the West of the project area. It is thought that the size and depth of burials varied by individual and that most graves bore wooden markers. The discovery of several numbered brass plates (some in the 200 range) also supports accounts that a significant amount of graves may have been removed. The initial Momentum GPR field work investigated subsurface features within five grids on the South facing slope. For comparative purposes, the intial project included a sixth grid, a long narrow grid surveyed over the road tracks (Road Grid). The grids established for the addendum overlap with the Road Grid area and are presented as part of the results for the addendum. The initial field work results revealed two feature areas with multiple potential grave locations, in addition to several in situ stone foundations for funeral monuments in areas bordering the GPR survey project boundaries. Due to the effects that water, particle size, and buried metal, a defininitve conclusion on how many intact graves are present is only possible through subsurface excavation. The road tracks that run West from the project area exhibits depressions that may be associated with graves and three carved stone bases. Adjacent to the West edge of the access road, there are several gravestones that have been displaced, persuading continued subsurface exploration for grave features beneath the roadway. GPR survey for this addendum was conducted in this access roadway to assess potential burial locations beneath the bounds of the roadway. The types of reflections found in the initial field work assisted in identying different reflective features that may be the location of potential graves. Along the West edge of the access road, there are several debris piles as a result of road grading and clearing vegetation obstructing passage. The GPR survey was conducted to determine if there are intact graves or graves that were opened to remove burials beneath the access roadway. When burials were removed the graves may or may not have been refilled. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 9 RESEARCH METHODOLOGY Ground penetrating radar was applied to the project area to determine if burials are present or whether culturally sensitive subsurface features are located within the APE. Steven Hackenberger, and CWAS staff conducted a GPR survey using a pulseEKKO Pro “Smartcart” with 500 MhZ transducers. Data recorded on a video logger were processed with Ekko Project software (Version 5 Sensors and Software). Radar images of these features are represented in profile and slice views. Radar images were further analyzed in 3D rendering. The examples of 3D images we include here are only for visualization. The rendering of reflection data include many extra factors that can only be known after example features are investigated. The unit is manufactured by Sensors & Software, (pulseEKKO Pro) and is configured on a “Smartcart” with 500 MhZ transducers. Measurements are recorded on a video data logger and stored on a CF card. Measurements are triggered with an odometer located on the back left tire of the cart. Features observed in radar reflection can be observed in cross-section (profile view), mapped in plan view (slice view) and in 3D. Features and possible occupation surfaces can be hypothesized based on analogous reflections. Due to the nature of the project surface and the limits of instruments and software, all feature signals will have a plus or minus error limit of about 30 cm (one ft) (horizontal and vertical). In order to evaluate subsurface features along the entire roadway, four, 30 x 4 - 5 meter grids were established. The grids were ordered 1-4 from east to west (Figure 2). Within several grids, the narrowing roadway or obstructing vegetation forced GPR survey lines to shift South or terminate before extending the full 30 meters (Grids 3-4). were also spliced together in the heavily disturbed and vegetated southern margin of the project area (Grid 4-5). During the initial fieldwork, many features could be identified and a sample of several types of features were identified for exploratory testing. Dr. Hackenberger returned to the project to brief project leaders (Momentum and Puyallup Tribe) to describe these features and mark their locations. These unique feature types were used as reference for determining features present during the addendum fieldwork. If features were identified after processing and interpreting survey results, those areas would be were marked with wooded stakes (orange paint) and enclosed with orange survey tape. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 10 Figure 2. Example of Grid (Grid 1). View: West. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 11 RESULTS The nature and origin of features found on GPR survey lines can be hypothesized based on analogous reflections. For a comparative analysis, typical historic grave features in a similar depositional and geological context in Orting, WA are shown below (Figure 3). In the example, graves with coffins were clearly represented in regularly spaced reflections at about one meter in depth. GPR reflections for this project are not consistent with intact or remanent grave features. Grids 1-5 covered an area approximately 480 square meters within the project area. The grids were each composed of eight individuals swatch lines that were walked with the GPR. The following section consists of results from each of the four grids within the project area. Figure 3. Seven example graves for comparison (not in current project area, comparison only). Grid 1 is a rectangle shaped 30 meters (E-W) x 4 meters (N-S) (Figure 4). The GPR results above 20 centimeters show surface moisture and silt fill, indicated by the red-Orange patches and dark bands (Figure 5). The results above 60 centimeters show show cobble/boulder distribution mostly between 80-100 centimeters below surface (Figure 6). Depressions and fill occur up to 30 centimeters deep. Results show that there are no reflections consistent with intact or remanent grave features. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 12 Figure 4. Plan view map of Grid 1. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 13 Figure 5. Grid 1 GPR reflections (top slice view 20 centimeters deep) show fill up to 30 centimeters below surface and are not consistent with intact or remenant grave features. Figure 6. Grid 1 GPR reflections (top slice view 60 centimeters deep) show cobble/boulder distribution mostly between 80-100 centimeters below surface. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 14 Grid 2 is a rectangle shaped 30 meters (E-W) x 4 meters (N-S) (Figure 7 and Figure 8). Figure 9 shows the GPR results for Grid 2, which show surface moisture and silt fill, indicated by the Red- Orange patches and dark bands at 20 centimeters below the surface. Depressions and fill occur up to 40 centimeters deep. Results show that there are no reflections consistent with intact or remanent grave features. Figure 7. Plan view map of Grid 2. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 15 Figure 8. Boundary between Grid 1 and Grid 2. View: West. Figure 9. Grid 2 GPR reflections (top slice view 20 centimeters deep) show surface moisture and silt fill (bottom Line 3 view). The red oval marks possible metal object. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 16 Grid 3 is a rectangle shaped 30 meters (E-W) x 4 meters (N-S) (Figure 10 and Figure 11). Figure 12 shows the GPR results for Grid 3, which show cobbles and bouldars distributed between 50 and 100 centimeters below the surface, indicated by the Red-Orange patches and dark bands. Several artifacts associated with grave features were found on the surface within Grid 3, including a cast iron leg or fence part and a coffin identification number plate (Figure 13). At the boundary between Grid 3 and Grid 4, an obelisk grave marker was located on the south side of the graded roadway (Figure 14). Results show that there are no reflections consistent with intact or remanent grave features. Figure 10. Plan view map of Grid 3, note the swath area shifted to the south. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 17 Figure 11. Boundary between Grid 3 and Grid 4. View: West. Figure 12. Grid 3 GPR reflections (top slice view 40 centimeters deep) show cobble/boulder distribution primarily between 50-100 centimeters below the surface (bottom Line 4 view). Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 18 Figure 13. Cast iron leg or fence part (left) and coffin identification number plate (right) found within Grid 3. Figure 14. The location (left) and details (right) of an obelisk grave marker found at the boundary between Grid 3 and Grid 4. View: Southwest. Grid 4 is a rectangle shaped 20 meters (E-W) x 4 meters (N-S) with a 5 meter x 2.5 meter extension on the west end (Figure 15 and Figure 16). Figure 17 and Figure 18 show the GPR results for Grid 4, which show cobbles and bouldars distributed between 80 and 100 centimeters below the surface, indicated by the Red-Orange patches and dark bands. Two grave markers were found adjacent to the Grid 4 boundaries (Figure 19). Results show that there are no reflections consistent with intact or remanent grave features. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 19 Figure 15. Plan view map of Grid 4. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 20 Figure 16. Grid 4 area, note the stone grave marker in the center right. View: East. Figure 17. Grid 4 GPR reflections (top slice view 40 centimeters deep) show cobble/boulder distribution primarily between 80-100 centimeters below the surface (bottom Line 4 view). Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 21 Figure 18. Grid 4 path extension GPR reflections (top slice view 80 centimeters deep) show cobble/boulder distribution primarily between 80-100 centimeters below the surface (bottom Line 4 view). Figure 19. Two grave markers located within the boundaries of Grid 4. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 22 CONCLUSIONS AND RECOMMENDATIONS GPR reflections are most strongly influenced by water and particle size. The reflections in the project area are most likely the result of cobble and boulder sized rock, and sometimes metal. The rock appearing in reflections can occur in small piles, on the edge of pits, or in the bottom or top of a pit. The expected variation in grave size and depth, and the possible removal of some burials, adds complexity to interpretations. Only excavation will determine the presence or absence of human remains, or identify the configuration of grave related stone monuments, cobble cairns, or cobble spoil. Some rock may have been placed as part of path or "road" maintenance. GPR reflections are not consistent with intact or remnant grave features. However, due to the proximity to possible grave sites within the original project area, a monitor is recommended for all ground disturbing activities. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 23 REFERENCES CITED Marquette University 2020 Library Archives. Electronic document, https://www.marquette.edu/library/archives/Mss/BCIM/BCIM-series1-1-paper_Stephan.php, accessed August 10, 2020. Ground Penetrating Radar Survey for the St. George Cemetery DRAFT Prepared for Momentum Civil Engineering Consultants 1145 Broadway, Suite 115 Tacoma, WA 98402 Prepared by Steve Hackenberger, (Phd) and Josh Allen (M.S) Central Washington Anthropological Survey Central Washington University, 400 East University Way Ellensburg, WA 98926-7523 DRAFT August 2020 Central Washington Anthropological Survey iii TABLE OF CONTENTS INTRODUCTION.............................................................................................................................. 4 Project Background .................................................................................................................... 5 RESEARCH METHODOLOGY ..................................................................................................... 7 RESULTS ........................................................................................................................................... 9 CONCLUSIONS AND RECOMMENDATIONS ......................................................................... 15 LIST OF FIGURES FIGURE 1. PROJECT AREA. (NOT INCLUDED IN DRAFT). ....................................................................... 4 FIGURE 2. EXAMPLE OF GRID (GRID 1). ................................................................................................ 8 FIGURE 3. SEVEN EXAMPLE GRAVES FOR COMPARISON (NOT IN CURRENT PROJECT AREA, COMPARISON ONLY). .......................................................................................................................................... 9 FIGURE 5. GPR RESULTS: SLICE VIEW GRIDS 1,2,3 4-5, EST. DEPTH 3 FEET. .................................... 10 FIGURE 6. GRID 1 (0N0E IN FOREGROUND) FEATURES 1 A&B CENTER-RIGHT, AND FEATURE 3 B FAR RIGHT. ......................................................................................................................................... 10 FIGURE 7. GRID 3 (ROAD), LINE 13 SHOWING AN UNKNOWN LINEAR FEATURE................................... 12 FIGURE 8. GRID 3: 40 CM DEPTH SLICE. NOTE ONE TO TWO METER LONG LINEAR FEATURES BETWEEN 10.5 AND 13.5 METERS INTERSECTING LINE 7. ............................................................................ 13 FIGURE 9. GRID 3: 60 CM DEPTH SLICE. .............................................................................................. 13 FIGURE 10. MAP OF FEATURES WITH PROJECT AREA. .......................................................................... 15 ATTACHMENTS Attachment A: Selection of GPR data. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 4 INTRODUCTION In August of 2020 Momentum Civil Engineering Consultants contracted with Central Washington Anthropological Survey (CWAS) to deploy Ground Penetrating Radar (GPR) as a non- destructive method of identifying possible features within five grids set up in the St. George Cemetery project area. Eight grids were placed along a proposed road in an effort to identify grave features (Figure 1). Dr. Steven Hackenberger (Professor, CWU Dept. of Anthropology), James McLean, M.S. (Crew Chief), and two students (Aiden Gallagher and Astra Miller) conducted GPR survey within the Project Area (Figure 1). Figure 1. Project Area. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 5 Project Background Father Hylebos established the “St. George's Industrial School for Indians,” with support from Miss Katharine Drexel, and the devotion of lay teacher, Esther Stevenson. The Bureau of Catholic Indian Missions in Washington DC helped support grants from a group of Franciscan Sisters from Philadelphia. The Sisters convened their first classes on October 26, 1888. Boarding school policy was total assimilation into dominant culture and students included Puyallup, Yakima, Tulalip, Muckleshoot, and others. As a working farm, and children learned trades: the Sisters taught the girls to cook, sew, and raise chickens, while the chaplain, Father De Decker, helped the boys learn to handle horses and cows, clear land, build fences, and plant and harvest crops. St. George’s School had an enrollment of about 60 pupils in 1913 and “thrived” into the 1920s but closed due to the Great Depression. Bishop Shaughnessy, facing debt, closed the school in 1936. The link contains a history written by Corinna Laughlin, Pastoral Assistant for Liturgy St. James Cathedral, Seattle. Archival records, known to Puyallup historians include records and correspondence at Marquette University and the Puyallup Tribal Museum (Marquette University 2020). Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 6 The St. George Cemetery Project Area The cemetery is associated with the St. George boarding school. The cemetery area includes a gentle sloping, South facing slope. The soil consists of fine silt with cobble. Some cobble is no doubt naturally occurring but large cobbles and boulders also appear to have been used in protecting graves. The slope is forested and the project area includes several mature cedar. According to personal accounts, the cemetery has been the resting place for both staff and students from the St. George school. An unknown number of burials were placed in the cemetery and an unknown number of burials were relocated. Several full-size graves remain open to the West of the project area. The discovery of several numbered brass plates (some in the 200 range) also supports accounts that a significant amount of graves may have been removed. It is thought that the size and depth of burials varied by individual and that most graves bore wooden markers. There are several in situ stone foundations for funeral monuments in areas bordering the GPR survey project boundaries. The road tracks that run West from the project area exhibits depressions that may be associated with graves and three carved stone bases. GPR survey was conducted in this area as a test of the types of reelections that might be located inside the marked project boundaries. North of this road two graves with cobble mounds are fenced with metal pipe. The area was too overgrown to include in out GPR test. The GPR survey was conducted to determine what types of features might be identified that may represent intact graves or graves that were opened to remove burials. When burials were removed the graves may or may not have been refilled. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 7 RESEARCH METHODOLOGY Ground penetrating radar was applied to the project area to determine if burials are present or whether culturally sensitive subsurface features are located within the APE. Steven Hackenberger, and CWAS staff conducted a GPR survey using a pulseEKKO Pro “Smartcart” with 500 MhZ transducers. Data recorded on a video logger were processed with Ekko Project software (Version 5 Sensors and Software). Radar images of these features are represented in profile and slice views. Radar images were further analyzed in 3D rendering. The examples of 3D images we include here are only for visualization. The rendering of reflection data include many extra factors that can only be known after example features are investigated. The unit is manufactured by Sensors & Software, (pulseEKKO Pro) and is configured on a “Smartcart” with 500 MhZ transducers. Measurements are recorded on a video data logger and stored on a CF card. Measurements are triggered with an odometer located on the back left tire of the cart. Features observed in radar reflection can be observed in cross-section (profile view), mapped in plan view (slice view) and in 3D. Features and possible occupation surfaces can be hypothesized based on analogous reflections. Due to the nature of the project surface and the limits of instruments and software, all feature signals will have a plus or minus error limit of about 30 cm (one ft) (horizontal and vertical). Due to the hill slope and larger trees, two grids (Grid 1 and 2) were placed north of the road tracks and one grid (Grid 3) was placed in the road tracks (Figure 2). GPR survey lines were also spliced together in the heavily disturbed and vegetated southern margin of the project area (Grid 4- 5). For comparative purposes, a long narrow grid was also surveyed over the road tracks to the West of Grid 3 (Road Grid). Although many features can be identified, a sample of several types of features were identified for exploratory testing. Dr. Hackenberger returned to the project to brief project leaders (Momentum and Puyallup Tribe) to describe these features and mark their locations. These features are reviewed under results with map locations, table descriptions, GPR splice and profile images. After processing and interpreting survey results, during a field debriefing several areas were marked with wooded stakes (orange paint) and enclosed with orange survey tape. These are labeled as they appear in Table 1 and Table 2. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 8 Figure 2. Example of Grid (Grid 1). Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 9 RESULTS The nature and origin of features found on GPR survey lines can be hypothesized based on analogous reflections. For a comparative analysis, typical historic grave features in a similar depositional and geological context in Orting, WA are shown below (Figure 3). In the example, graves with coffins were clearly represented in regularly spaced reflections at about one meter in depth. The following section consists of results from each of the five grids within the project area, concentrating on those grids which contained observable unnatural subsurface features. Attachment A (not included in draft) includes a selection of slice view and line view data from all eight grids. The grids are composed of individual lines that were walked with the GPR. Figure 3. Seven example graves for comparison (not in current project area, comparison only). Grids 1 through five covered an area of approximately 20 square meters within the project area. Figure 4 depicts a slice view of all five grids at a depth of approximately three feet below surface. The white circles indicate trees within the survey area while the dashed circles indicate features. Features were located in Grids one, two , and three while girds four and five were limited to only potential features due to vegetation and disturbance. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 10 Figure 5. GPR RESULTS: Slice view Grids 1,2,3 4-5, est. depth 3 feet. Grid 1 is L shaped 20 meters (E-W) x 10 meters (N-S). Results include many areas of reflections that may represent smaller graves or the scattered spoil from open graves. Some ten features stand out and are mapped and marked on the ground for possible exploration (Figure 1Table 1. Grid 1 Features and Recommendations and Table 1). Figure 6. Grid 1 (0N0E in foreground) Features 1 A&B center-right, and Feature 3 B far right. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 11 Table 1. Grid 1 Features and Recommendations Grid Marker Features Descriptions Recommendations 1 AB Stake located N and between A&B Best example in West Cluster. A 1-2 m N-S, 3-5ft deep B1-2 m N-S, 3-5 ft deep. Expose to determine cobble cover grave or cobble spoil. 1 BC Stake located N and between B&C C 1 m N-S, 4-6 ft deep. Test if possible, graves are confirmed for Fea. A&B? 1 D Stake located N of isolated feature. 1-1.5 m N-S, 3-5 ft deep. Expose to determine cobble cover or cobble spoil. 1 E Stake located N of isolated feature. 1-1.5 m N-S, 3-5 ft deep. As above. 1 F Stake located N of isolated feature. 1-1.5 m N-S, 3-5 ft deep. As above. 1 H Stake located N of isolated feature. 1-1.5 m N-S, 3-5 ft deep. Test as example of deepest isolated reflection? 1 G Stake located N and between two features. Best example in East Cluster. 1-2 m N-S, 2-5 ft. deep Expose to determine cobble cover grave or cobble spoil. Grid 2 a smaller rectangle 7 meters (E-W) x 5 meters (N-S) that when combined with Grid 1 covers the NE portion of a larger rectangle. Numerous features are apparent in this smaller area, and nine features are mapped and marked for possible investigation (Table 2). Figure 7 depicts reflection features from Line 4 (lower right), Line 6 (lower right), and Line 9 (upper right). Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 12 Figure 7. Grid 2 depth slice estimated 60 cm approximately two feet. Grid 3 is a long thin rectangle 20 meters (E-W) x 20 meters (E-W) that covers the road tracks south of Grid 1. Again numerous features can be identified, and five stand out for possible testing (Figure 8, Figure 9, andFigure 10; Table 2). Grid 3 contains two sets of features that appear most like graves with contents (Features 3A and 3B). There are two-meter-long linear features at three meters, between 14 and 15 meters and two features between 25 and 30 meters (Figure 8). The lower view is a profile for Line 13 showing cone reflections starting at 20-50 cm flanking strong reflections at 1 m deep. Note trough like reflections at 1-3 m, 14-16 m and 25-27 and 28-30 m. Several stone foundations (black squares) are located along the north edge of road at 0 m, 11 m (dislocated at base of tree), and 27 m. Open graves (indicated by blue dashed circles) are also north of road at 8 m and 11 m. Larger shallow depressions are located in the road at 1-2 m. and 14-16 m. Figure 10 depicts two to three-meter-long linear features at six and eight meters intersecting Line 3. Note rectangular feature (2 x 0.5 m) at 19 meters. These features appear most like graves with contents. Figure 8. Grid 3 (Road), Line 13 showing an unknown linear feature. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 13 Figure 9. Grid 3: 40 cm depth slice. Note one to two meter long linear features between 10.5 and 13.5 meters intersecting Line 7. Figure 10. Grid 3: 60 cm depth slice. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 14 Table 2. Grid 2,3,4 and 5 Features and Recommendations Grid Marker Features Descriptions Recommendations 2 A Stake located N and between three features. 1-2 m N-S, 3-5ft deep. Expose to determine cobble cover grave or cobble spoil. B Stake located N and between two features. 1 m N-S, 3-5 ft deep. Test if possible graves are confirmed for Fea. A? 3 A Stake located N of three features. 1-1.5 m N-S, 2-6 ft deep. Expose to determine cobble cover or cobble spoil. Contents? 3 B Stake located N of two features. 1.5-2 m N-S, 3-5 ft deep. As above. Contents? 4 A Stake located N of isolated feature. 1-1.5 m N-S, 3-5 ft deep. Possible feature with metal of stone. 4 B Stake located N of isolated feature. 1-1.5 m N-S, 3-5 ft deep. Test as it is in disturbed depression? Grids 4 and 5 are composed of lines that were walked in the southern most project area. Vegetation and disturbance make this area difficult to survey and interpret. Several possible features are present. Two of these features may contain stone or metal, and two are mapped and marked assuming it might be desirable to explore a more disturbed margin of the project area. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 15 CONCLUSIONS AND RECOMMENDATIONS GPR reflections are most strongly influenced by water and particle size. The reflections in the project area are most likely the result of cobble and boulder sized rock, and sometimes metal. The rock appearing in reflections can occur in small piles, on the edge of pits, or in the bottom or top of a pit. The expected variation in grave size and depth, and the possible removal of some burials, adds complexity to interpretations. Only excavation will determine the presence or absence of human remains, or identify the configuration of grave related stone monuments, cobble cairns, or cobble spoil. Some rock may have been placed as part of path or "road" maintenance. It is possible that some rock is not culturally placed, and this would require more geological explanation. The GPR depth slice results, for about three feet deep, show the most patterning. Strong reflections do occur above and below this depth in most of the survey area. Although features vary in size and depth, they appear to be oriented North-South and exhibit some regular spacing. Figure 11. Map of features with project area. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 16 The GPR survey identified two clusters of features with strong reflections. Most feature reflections are estimated to originate between two and five feet deep. Again, these features likely represent grave activity, but it is not possible to say if they are intact, or if they are t he result of opened graves (removal). You can see from the map legend where the brass number plates were located (large triangle) with the metal detector (see Figure 11) . Based on metal signals there are probably more plates still buried near the surface in this area. The 0N-OE markers are indicated (solid circle) for Grids 1-3. Annotations are included for the stronger feature reflections (ovals in dotted line). Two clusters of these features are enclosed in dashed lines. Weaker reflections include question marks (?). The map legend indicates symbols for: large trees, magnetic signals from a metal detector, GPR reflections that may results from metal and/or stone, and an area with four brass plates with numbers. Due to the presence of possible graves within the project area, CWAS recommends that test excavation be conducted within a selection of the features described above. Potential grave locations were located within the project area. It is also advisable that a monitor is present during all future ground disturbing activities within the project area. Ground Penetrating Radar St. George Cemetery 2020 Central Washington Anthropological Survey 17 REFERENCES CITED Marquette University 2020 Library Archives. Electronic document, https://www.marquette.edu/library/archives/Mss/BCIM/BCIM-series1-1-paper_Stephan.php, accessed August 10, 2020.