Loading...
REV1 RESUB 1 - APPROVED STM_ - Drainage Addendum 05-17-2021REVISION BLD2020-001 7- May 20 2021 RESUB 1 of �0'P.M'E'ND Emb DEPARTMENT Es INSIGHT ENGINEERING CO. Applicant: Kisan Enterprise, LLC 20607 State Route 9 S.E, Snohomish, WA 98296 Ph: 425-402-9900 Fax: 425-489-0222 DRAINAGE ADDENDUM For KISAN ENTERPRISES Prepared for The City of Edmonds 121 5th Ave N Edmonds, WA 98020 425-771-0220 Project Site Location: 22810 Edmonds Way, Edmonds, WA 98020 Tax Id:27033600102300 IECO Project: 20-1062 COMPLIES WITH APPLICABLE CITY STORMWATER CODE REVISIONS ONLY Contact: IECO P.O. Box 1478 Everett, WA98206 425-303-9363 Certified Erosion and Sedimentation Control Lead: Brian R. Kalab (425)303-9363 Stormwater Site Plan Prepared By: Shilpa Xavier, E. I. T. Preparation Date: R. k May 18, 2021 v 56499 (� GISTti�G� P.O Box 1478 • Everett, WA 98206 • P: 425.303.9363 05/20/2021 F:425.303.9362 • info@insightengineering.net Summary for Drainage Addendum This report has been prepared for the proposed project Kisan Enterprises to present the updated site hydraulic calculations based on the reduced detention requirement per ECDC 18.030.060. Flow control requirements for this project were approved to be met by using a detention vault located under the access drive. As the project falls within Edmonds Way Basin, this detention system can be reduced in size per ECDC 18.030.060 as below. The new detention system will be a buried CMP pipe. "(B) Edmonds Way Specific Requirements. After applying the requirements in subsection (D)(5)(b)(iv)(A) of this section, for all remaining project site runoff (e.g., from unmanaged surfaces, or from overflow from on -site BMPs), the post -development 10- and 100 year recurrence interval peak flows shall not exceed 0.25 and 0.45 cubic feet per second per acre of impervious surface area, respectively. See the Edmonds Stormwater Addendum for additional details. " Total Impervious Area = 23,658 SF Allowed 10-year flows: 0.25 X 23,658 SF/ 43,560 Acres = 0.14 cfs Allowed 100-year flows: 0.45 X 23,658 SF/ 43,560 Acres = 0.24 cfs The project area has been divided into Subbasin-1 and Subbasin-2. Subbasin-1 includes Building- C, onsite access drive. These areas will be connected to the proposed detention pipe. The detention pipe (130 LF X 9') with a dead storage of l' and detention volume of 7,840 CF will be located under the access drive. The developed site drainage will be discharged to the existing drainage system on Edmonds Way to continue its natural drainage flow path. Water quality will be met by 1-27" single cartridge steel catch basin stormfilter manufactured by Contech Engineered Solutions LLC located upstream of detention. The sizing sheet and GULD approval for Stormfilter is attached under Appendix A. Subbasin-2 includes Building -A, Building-B, Building-D and Frontage access road and sidewalk. The runoff from these areas will be directed existing drainage system on Edmonds Way to continue its natural drainage flow path. A SWPPP has been included in the Appendix B. The total the post -development 10- and 100-year recurrence interval peak flows from these subbasins is less than the maximum flow shown above. Please refer to the table below, Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -I- Site Hydraulic calculation, WWHM-1 and WWHM-2 reports for more details. WWHM-1 shows the modelling analysis of the entire project performed as a single combined POC-1. The mitigated flows from POC-1 are less than the required maximum flows. WWHM-2 shows the detention sizing with the flows from each subbasin separated out. The summary of the flows from each WWHM is shown below: Return Subbasin-1 Subbasin-2 Total Project Mitigated Required Max Flow Period (from (from (Subbasin-1 POC-1 flows WWHM-2) WWHM-2) +Subbasin-2) (from (from WWHM-2) WWHM-1) 10- 0.01 cfs 0.10 cfs 0.11 cfs 0.10 cfs 0.14 cfs year 100- 0.02 cfs 0.15 cfs 0.17 cfs 0.15 cfs 0.24 cfs year Site Hydraulic Calculation Total Site Area = 0.71 Acres Total Frontage Area = 0.06 Acres Total Area Included in the Analysis = 0.77 Acres Subbasin-1 = 0.51 Acres Subbasin-2 = 0.26 Acres Total Area Included in the Analysis = 0.77 Acres The area included in the analysis will be the area where the new impervious is proposed. From the Soil Conservation Service Map of Snohomish County, most of the site contains Everett soils that have a hydrologic classification of Type "A". 1.1 Sub Basin-1 Summary Subbasin-1 includes Building-C, onsite access drive. These areas will be connected to the revised detention vault. Existing Sub Basin-1 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -2- Sub Basin-1 Existing Basin Area REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT = 0.51 Acres = 0.51 Acres Entire existing basin was modeled as forested areas. Refer to the Existing Basin Map, WWHM-1 and WWHM-2 reports for more details. Developed Sub Basin-1 Sub basin-1 = 0.51 Acres Developed Basin Area Impervious: Roof Area Walkway Road Total Developed Impervious Pervious Area Detention Volume Required: 7,840 CF Detention Volume Provided: 7,840 CF = 0.51 Acres = 0.09 Acres ( 3,933 SF) = 0.01 Acres ( 310 SF) = 0.20 Acres ( 8,553 SF) = 0.30 Acres (12,751 SF) = 0.21 Acres Refer to the Developed Basin Map, WWHM-1 and WWHM-2 reports for more details. 1.2 Sub Basin-2 Summary Subbasin-2 includes Building -A, Building-B, Building-D and Frontage access road and sidewalk. The runoff from these areas will be directed existing drainage system on Edmonds Way to continue its natural drainage flow path. Existing Sub Basin- 2 Sub Basin-2 Existing Basin Area = 0.26 Acres = 0.26 Acres Entire existing basin was modeled as forested areas. Refer to the Existing Basin Map, WWHM-1 and WWHM-2 reports for more details. Insight Engineering Co. - Stormwater Site Plan 5/20/21 -3- Developed Sub Basin-2 Sub basin-2 = 0.26 Acres Developed Basin Area = 0.26 Acres Impervious: Roof Area = 0.20 Acres ( 8,912 SF) Asphalt/Sidewalk = 0.04 Acres (1,950 SF) Total Developed Impervious = 0.24 Acres (10,862 SF) Pervious Area = 0.02 Acres Total New Impervious Area: 23,658 SF (0.54 Acres) Refer to the Developed Basin Map, WWHM-1 and WWHM-2 reports for more details. Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEPARTMENT -4- 0PAID MON IN CA E �x STOP 7 I� SIGN TBRJ I I EX. INGRESS, EC SS I I N EASEMENT A.F. N 7801230217 h w 1 z II N 8 0"49" W I I lt EX. 6" 70 FH TEE I „ I Iw 6 I k N 7 \ hl I I x J � IJ E7L I �I 9 1 — \ CB RIM 351.1, T 1 7\\\ 270336,10100300 \ EDMONDSWAY LLC \ 9504 EDMONL�S WAY CB RIM 349.81 EDMONDS, WAI 9 5 FT It, SETBAC LINE- R 2, 3 & 4 I I \ 0 8 REVISION a=aio.za' May 20 2021 \ L=61'2942" C. BEARING S 68'46"01" E CORD 4I9.46' oEVE�oaraENisEavicEs oevnRTMENT s ` 3 I- SS \ \ 348 _ !SLOPE SEMEN \ A.F. ` EX. S.S.M.H. OP=348t INV=341.74 N0. 9070150390 O H 15-769 \ 347.9 FT \ 12\ ET K LIN C /CA L \ P INV=345. 14-36' INV=344.74-12"NW O.F.=349.54 STE EX. S.S.M.H. TOP=350.23 INV=343.99 s.r ??8j0Fk/S7jyC F�'NOA'pS 7S' S�Q9CK U,yF � _ l> F �c �F S L 0 T 1 6 27OJ3600102200 TRIMARK-WESTGATE APARTMENTS LLC 22816 EDMONDS WAY EDMONDS, WA. 98020 EXISTING RETIREMENT HOUSING BUILDING SUB BASIN-1 (0.51 AC) SUB BASIN-2 (0.26 AC) SCALE: 1 " = 40' 0 20 40 EXISTING BASIN MAP 0 0 ♦ — R.. err = -1rr�T3iiRRii'i �! . rAw" �201, — • a .�ML W-1 4/ III, �� �� .� �� . Q I ��r �1� 1$,I L hel� a EASEMENT A.F. N 7801230217 z II. 65,00' Ig I I 1 N 8 049" W EX. 6" 70 FH TEE C I II� )k �I �I I� �e �I I I� \y IX I Yln 1 - \ CB RIM 351.1, T � 1 7\\\ 27033600100100 \ EDMONDSWAY LLC \ 9504 EDMONdS WAY CB RIM 349.81 EDMONDS, WAI 9 5 FT Ih SETBAC LINE- R 2, 3 & 4 I 1�� - / 17 99 / I �. U7VI2 AN 'D BL C n �NrrAt ffi 24 25 rev a UN17'13 x 7"• 10• 15 I BSBY 10, j5 II \�f\R BSg� \p f\R \ \ I 8 L 0 T 1 6 27OJ3600102200 TRIMARK-WESTGATE APARTMENTS LLC 22816 EDMONDS WAY EDMONDS, WA. 98020 EXISTING RETIREMENT HOUSING BUILDING SUB BASIN-1 (0.51 AC) SUB BASIN-2 (0.26 AC) SCALE: 1 " = 40' 0 20 40 DEVELOPED BASIN MAP WWHM-I-SINGLE COMBINED POC WWHM2012 PROJECT REPORT Project Name: Kisan Site Name: Kisan Enterprises Site Address: 22810 Edmonds Way City : Edmonds Report Date: 5/18/2021 MGS Regoin Puget East Data Start 1901/10/1 Data End : 2058/09/30 DOT Data Number: 03 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 : Ex Subbasin-1 Bypass: No Groundwater: No Pervious Land Use acre C, Forest, Mod .51 Pervious Total 0.51 Impervious Land Use acre Impervious Total 0 Basin Total 0.51 Element Flows To: Surface Interflow Name : Ex Subbasin-2 Bypass: No Insight Engineering Co. - Stormwater Site Plan Groundwater 5/20/21 REVISION May 20 2021 DEPARTMENT -5- Groundwater: No Pervious Land Use acre C, Forest, Mod .26 Pervious Total 0.26 Impervious Land Use acre Impervious Total 0 Basin Total 0.26 Element Flows To: Surface Interflow MITIGATED LAND USE Name : Dev Subbasin-1 Bypass: No Groundwater: No Pervious Land Use acre C, Lawn, Mod .21 Pervious Total 0.21 Impervious Land Use acre ROADS FLAT 0.2 ROOF TOPS FLAT 0.09 SIDEWALKS FLAT 0.01 Impervious Total 0.3 Basin Total 0.51 Element Flows To: Surface Interflow Tank 1 Tank 1 Name : Dev Subbasin-2 Bypass: Yes Insight Engineering Co. - Stormwater Site Plan Groundwater Groundwater 5/20/21 REVISION May 20 2021 DEPARTMENT IM Groundwater: No Pervious Land Use acre C, Lawn, Mod .02 Pervious Total 0.02 Impervious Land Use acre ROADS MOD 0.04 ROOF TOPS FLAT 0.2 Impervious Total 0.24 Basin Total 0.26 Element Flows To: Surface Interflow Name : Tank 1 Tank Name: Tank 1 Depth: 9 ft. Tank Type Circular Diameter 9 ft. Length : 130 ft. Discharge Structure Riser Height: 8 ft. Riser Diameter: 12 in. Notch Type: Rectangular Notch Width: 0.016 ft. Notch Height: 0.540 ft. Orifice 1 Diameter: 0.26 in. Elevation: 0 ft. Element Flows To: Outlet 1 Outlet 2 Groundwater Tank Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.000 0.000 0.000 0.000 0.1000 0.005 0.000 0.000 0.000 0.2000 0.007 0.001 0.000 0.000 0.3000 0.009 0.001 0.001 0.000 0.4000 0.011 0.003 0.001 0.000 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEPARTMENT -7- 0.5000 0.012 0.004 0.001 0.000 0.6000 0.013 0.005 0.001 0.000 0.7000 0.014 0.006 0.001 0.000 0.8000 0.015 0.008 0.001 0.000 0.9000 0.016 0.009 0.001 0.000 1.0000 0.016 0.011 0.001 0.000 1.1000 0.017 0.013 0.001 0.000 1.2000 0.018 0.015 0.002 0.000 1.3000 0.018 0.016 0.002 0.000 1.4000 0.019 0.018 0.002 0.000 1.5000 0.020 0.020 0.002 0.000 1.6000 0.020 0.022 0.002 0.000 1.7000 0.021 0.024 0.002 0.000 1.8000 0.021 0.027 0.002 0.000 1.9000 0.021 0.029 0.002 0.000 2.0000 0.022 0.031 0.002 0.000 2.1000 0.022 0.033 0.002 0.000 2.2000 0.023 0.036 0.002 0.000 2.3000 0.023 0.038 0.002 0.000 2.4000 0.023 0.040 0.002 0.000 2.5000 0.024 0.043 0.002 0.000 2.6000 0.024 0.045 0.003 0.000 2.7000 0.024 0.047 0.003 0.000 2.8000 0.024 0.050 0.003 0.000 2.9000 0.025 0.052 0.003 0.000 3.0000 0.025 0.055 0.003 0.000 3.1000 0.025 0.057 0.003 0.000 3.2000 0.025 0.060 0.003 0.000 3.3000 0.025 0.063 0.003 0.000 3.4000 0.026 0.065 0.003 0.000 3.5000 0.026 0.068 0.003 0.000 3.6000 0.026 0.070 0.003 0.000 3.7000 0.026 0.073 0.003 0.000 3.8000 0.026 0.076 0.003 0.000 3.9000 0.026 0.078 0.003 0.000 4.0000 0.026 0.081 0.003 0.000 4.1000 0.026 0.084 0.003 0.000 4.2000 0.026 0.086 0.003 0.000 4.3000 0.026 0.089 0.003 0.000 4.4000 0.026 0.092 0.003 0.000 4.5000 0.026 0.094 0.003 0.000 4.6000 0.026 0.097 0.003 0.000 4.7000 0.026 0.100 0.004 0.000 4.8000 0.026 0.103 0.004 0.000 4.9000 0.026 0.105 0.004 0.000 5.0000 0.026 0.108 0.004 0.000 5.1000 0.026 0.111 0.004 0.000 5.2000 0.026 0.113 0.004 0.000 5.3000 0.026 0.116 0.004 0.000 5.4000 0.026 0.118 0.004 0.000 5.5000 0.026 0.121 0.004 0.000 5.6000 0.026 0.124 0.004 0.000 5.7000 0.025 0.126 0.004 0.000 5.8000 0.025 0.129 0.004 0.000 5.9000 0.025 0.131 0.004 0.000 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -8- 6.0000 0.025 0.134 0.004 0.000 6.1000 0.025 0.137 0.004 0.000 6.2000 0.024 0.139 0.004 0.000 6.3000 0.024 0.142 0.004 0.000 6.4000 0.024 0.144 0.004 0.000 6.5000 0.024 0.146 0.004 0.000 6.6000 0.023 0.149 0.004 0.000 6.7000 0.023 0.151 0.004 0.000 6.8000 0.023 0.153 0.004 0.000 6.9000 0.022 0.156 0.004 0.000 7.0000 0.022 0.158 0.004 0.000 7.1000 0.021 0.160 0.004 0.000 7.2000 0.021 0.162 0.004 0.000 7.3000 0.021 0.165 0.005 0.000 7.4000 0.020 0.167 0.005 0.000 7.5000 0.020 0.169 0.005 0.000 7.6000 0.019 0.171 0.007 0.000 7.7000 0.018 0.173 0.011 0.000 7.8000 0.018 0.174 0.015 0.000 7.9000 0.017 0.176 0.019 0.000 8.0000 0.016 0.178 0.024 0.000 8.1000 0.016 0.180 0.357 0.000 8.2000 0.015 0.181 0.931 0.000 8.3000 0.014 0.183 1.533 0.000 8.4000 0.013 0.184 1.984 0.000 8.5000 0.012 0.185 2.227 0.000 8.6000 0.011 0.186 2.463 0.000 8.7000 0.009 0.187 2.659 0.000 8.8000 0.007 0.188 2.841 0.000 8.9000 0.005 0.189 3.012 0.000 9.0000 0.000 0.189 3.174 0.000 9.1000 0.000 0.000 3.327 0.000 ANALYSIS RESULTS Stream Protection Duration Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.77 Total Impervious Area:O Mitigated Landuse Totals for POC #1 Total Pervious Area:0.23 Total Impervious Area:0.54 Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.013136 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -9- 5 year 0.02181 10 year 0.026732 25 year 0.031865 50 year 0.034968 100 year 0.037547 Flow Frequency Return Periods for Mitigated. Return Period Flow(cfs) 2 year 0.064268 5 year 0.08498 10 year 0.099859/ 0.54 acres = 25 year 0.120034 50 year 0.136093 100 year 0.153061/ 0.54 acres = Stream Protection Duration Annual Peaks for Predeveloped and Mitigated Year Predeveloped Mitigated 1902 0.018 0.069 1903 0.006 0.078 1904 0.016 0.090 1905 0.007 0.044 1906 0.003 0.047 1907 0.020 0.065 1908 0.013 0.056 1909 0.014 0.071 1910 0.024 0.066 1911 0.011 0.068 1912 0.049 0.115 1913 0.019 0.042 1914 0.004 0.162 1915 0.006 0.043 1916 0.010 0.069 1917 0.005 0.043 1918 0.013 0.062 1919 0.009 0.038 1920 0.012 0.055 1921 0.012 0.042 1922 0.014 0.057 1923 0.012 0.059 1924 0.006 0.075 1925 0.006 0.042 1926 0.011 0.078 1927 0.014 0.056 1928 0.009 0.054 1929 0.023 0.087 1930 0.012 0.097 1931 0.012 0.046 1932 0.009 0.052 1933 0.010 0.050 1934 0.031 0.107 1935 0.010 0.046 1936 0.017 0.053 1937 0.015 0.072 Insight Engineering Co. - Stormwater Site Plan POC #1 1849 < 0.25 => OK 2834 < 0.45 => OK POC #1 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -10- 1938 0.014 0.048 1939 0.001 0.066 1940 0.011 0.089 1941 0.011 0.075 1942 0.017 0.071 1943 0.005 0.078 1944 0.017 0.114 1945 0.012 0.077 1946 0.011 0.056 1947 0.008 0.050 1948 0.026 0.064 1949 0.022 0.101 1950 0.011 0.043 1951 0.014 0.067 1952 0.045 0.111 1953 0.036 0.107 1954 0.010 0.056 1955 0.008 0.049 1956 0.006 0.039 1957 0.015 0.057 1958 0.036 0.071 1959 0.022 0.069 1960 0.008 0.054 1961 0.022 0.152 1962 0.011 0.060 1963 0.005 0.042 1964 0.010 0.113 1965 0.026 0.086 1966 0.005 0.051 1967 0.010 0.058 1968 0.013 0.052 1969 0.009 0.057 1970 0.017 0.067 1971 0.028 0.070 1972 0.018 0.201 1973 0.021 0.111 1974 0.014 0.085 1975 0.033 0.099 1976 0.013 0.085 1977 0.008 0.040 1978 0.025 0.073 1979 0.007 0.065 1980 0.012 0.065 1981 0.013 0.072 1982 0.008 0.053 1983 0.021 0.075 1984 0.005 0.070 1985 0.012 0.069 1986 0.010 0.045 1987 0.021 0.070 1988 0.015 0.047 1989 0.012 0.046 1990 0.015 0.049 1991 0.012 0.077 1992 0.018 0.078 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT - 11 - 1993 0.015 0.089 1994 0.026 0.060 1995 0.006 0.042 1996 0.031 0.063 1997 0.013 0.052 1998 0.013 0.066 1999 0.000 0.070 2000 0.009 0.072 2001 0.007 0.065 2002 0.025 0.095 2003 0.014 0.050 2004 0.016 0.082 2005 0.023 0.121 2006 0.009 0.053 2007 0.010 0.075 2008 0.013 0.059 2009 0.008 0.056 2010 0.006 0.069 2011 0.008 0.048 2012 0.011 0.070 2013 0.010 0.052 2014 0.006 0.055 2015 0.029 0.100 2016 0.004 0.047 2017 0.023 0.102 2018 0.041 0.121 2019 0.044 0.092 2020 0.015 0.077 2021 0.017 0.072 2022 0.006 0.090 2023 0.014 0.098 2024 0.055 0.132 2025 0.011 0.055 2026 0.020 0.060 2027 0.008 0.073 2028 0.004 0.034 2029 0.014 0.055 2030 0.030 0.083 2031 0.007 0.038 2032 0.006 0.046 2033 0.007 0.048 2034 0.008 0.051 2035 0.032 0.072 2036 0.017 0.051 2037 0.003 0.068 2038 0.019 0.066 2039 0.001 0.105 2040 0.006 0.055 2041 0.009 0.063 2042 0.034 0.075 2043 0.014 0.083 2044 0.020 0.058 2045 0.012 0.054 2046 0.014 0.057 2047 0.009 0.069 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -12- 2048 0.012 0.058 2049 0.012 0.086 2050 0.008 0.054 2051 0.013 0.089 2052 0.007 0.056 2053 0.013 0.058 2054 0.024 0.092 2055 0.005 0.056 2056 0.005 0.073 2057 0.008 0.046 2058 0.010 0.079 Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0554 0.2013 2 0.0495 0.1619 3 0.0451 0.1520 4 0.0439 0.1324 5 0.0411 0.1208 6 0.0365 0.1206 7 0.0362 0.1147 8 0.0342 0.1137 9 0.0328 0.1133 10 0.0316 0.1111 11 0.0311 0.1105 12 0.0306 0.1071 13 0.0298 0.1068 14 0.0289 0.1052 15 0.0276 0.1017 16 0.0265 0.1010 17 0.0262 0.0997 18 0.0261 0.0988 19 0.0250 0.0982 20 0.0250 0.0969 21 0.0244 0.0950 22 0.0239 0.0922 23 0.0229 0.0919 24 0.0227 0.0904 25 0.0227 0.0896 26 0.0223 0.0893 27 0.0217 0.0891 28 0.0217 0.0889 29 0.0212 0.0866 30 0.0209 0.0865 31 0.0207 0.0855 32 0.0205 0.0849 33 0.0200 0.0845 34 0.0198 0.0828 35 0.0193 0.0827 36 0.0192 0.0821 37 0.0180 0.0787 38 0.0180 0.0783 39 0.0179 0.0781 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -13- 40 0.0173 0.0780 41 0.0172 0.0779 42 0.0170 0.0774 43 0.0168 0.0772 44 0.0168 0.0769 45 0.0166 0.0754 46 0.0159 0.0754 47 0.0157 0.0752 48 0.0155 0.0748 49 0.0154 0.0746 50 0.0152 0.0732 51 0.0150 0.0732 52 0.0149 0.0727 53 0.0148 0.0725 54 0.0144 0.0721 55 0.0144 0.0719 56 0.0142 0.0717 57 0.0141 0.0715 58 0.0140 0.0714 59 0.0140 0.0711 60 0.0138 0.0711 61 0.0138 0.0704 62 0.0138 0.0704 63 0.0137 0.0703 64 0.0136 0.0698 65 0.0135 0.0696 66 0.0133 0.0695 67 0.0131 0.0693 68 0.0130 0.0689 69 0.0128 0.0688 70 0.0127 0.0688 71 0.0127 0.0688 72 0.0126 0.0679 73 0.0126 0.0676 74 0.0125 0.0675 75 0.0125 0.0673 76 0.0124 0.0664 77 0.0122 0.0660 78 0.0121 0.0657 79 0.0121 0.0655 80 0.0121 0.0653 81 0.0120 0.0653 82 0.0120 0.0649 83 0.0119 0.0646 84 0.0119 0.0637 85 0.0119 0.0629 86 0.0118 0.0626 87 0.0117 0.0624 88 0.0115 0.0602 89 0.0114 0.0602 90 0.0114 0.0601 91 0.0113 0.0595 92 0.0112 0.0595 93 0.0111 0.0583 94 0.0110 0.0582 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -14- 95 0.0108 0.0580 96 0.0108 0.0579 97 0.0105 0.0572 98 0.0103 0.0568 99 0.0103 0.0567 100 0.0101 0.0565 101 0.0101 0.0563 102 0.0100 0.0560 103 0.0100 0.0560 104 0.0098 0.0559 105 0.0097 0.0558 106 0.0097 0.0558 107 0.0094 0.0556 108 0.0093 0.0554 109 0.0092 0.0550 110 0.0092 0.0548 111 0.0090 0.0547 112 0.0089 0.0546 113 0.0088 0.0543 114 0.0087 0.0540 115 0.0085 0.0537 116 0.0085 0.0536 117 0.0084 0.0535 118 0.0082 0.0529 119 0.0081 0.0525 120 0.0080 0.0524 121 0.0078 0.0524 122 0.0077 0.0518 123 0.0076 0.0515 124 0.0076 0.0512 125 0.0075 0.0511 126 0.0074 0.0509 127 0.0074 0.0505 128 0.0070 0.0501 129 0.0066 0.0499 130 0.0066 0.0495 131 0.0065 0.0487 132 0.0063 0.0482 133 0.0063 0.0482 134 0.0063 0.0478 135 0.0062 0.0472 136 0.0061 0.0469 137 0.0060 0.0467 138 0.0058 0.0464 139 0.0058 0.0462 140 0.0057 0.0458 141 0.0057 0.0456 142 0.0056 0.0455 143 0.0053 0.0450 144 0.0053 0.0436 145 0.0050 0.0430 146 0.0050 0.0428 147 0.0049 0.0428 148 0.0049 0.0425 149 0.0046 0.0425 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -15- 150 0.0045 0.0418 151 0.0041 0.0416 152 0.0035 0.0415 153 0.0027 0.0395 154 0.0026 0.0389 155 0.0011 0.0380 156 0.0006 0.0379 157 0.0002 0.0337 Stream Protection Duration POC #1 The Facility FAILED Facility FAILED duration standard for 1+ flows. Flow(cfs) Predev Mit Percentage Pass/Fail 0.0066 12736 79052 620 Fail 0.0069 11576 75061 648 Fail 0.0071 10526 71359 677 Fail 0.0074 9594 67960 708 Fail 0.0077 8782 64725 737 Fail 0.0080 8066 61780 765 Fail 0.0083 7428 58986 794 Fail 0.0086 6845 56385 823 Fail 0.0089 6296 53991 857 Fail 0.0091 5809 51623 888 Fail 0.0094 5327 49380 926 Fail 0.0097 4899 47288 965 Fail 0.0100 4509 45182 1002 Fail 0.0103 4181 43311 1035 Fail 0.0106 3848 41508 1078 Fail 0.0109 3544 39760 1121 Fail 0.0112 3275 38177 1165 Fail 0.0114 3031 36567 1206 Fail 0.0117 2803 35067 1251 Fail 0.0120 2615 33718 1289 Fail 0.0123 2443 32342 1323 Fail 0.0126 2290 31048 1355 Fail 0.0129 2121 29837 1406 Fail 0.0132 1985 28654 1443 Fail 0.0135 1868 27470 1470 Fail 0.0137 1763 26369 1495 Fail 0.0140 1654 25323 1531 Fail 0.0143 1562 24318 1556 Fail 0.0146 1478 23328 1578 Fail 0.0149 1393 22433 1610 Fail 0.0152 1324 21552 1627 Fail 0.0155 1242 20726 1668 Fail 0.0157 1173 19956 1701 Fail 0.0160 1120 19171 1711 Fail 0.0163 1053 18456 1752 Fail 0.0166 1001 17754 1773 Fail 0.0169 953 17107 1795 Fail 0.0172 901 16515 1832 Fail Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -16- 0.0175 868 15868 1828 Fail 0.0178 833 15276 1833 Fail 0.0180 800 14698 1837 Fail 0.0183 774 14148 1827 Fail 0.0186 740 13607 1838 Fail 0.0189 717 13112 1828 Fail 0.0192 688 12607 1832 Fail 0.0195 659 12117 1838 Fail 0.0198 630 11682 1854 Fail 0.0201 598 11254 1881 Fail 0.0203 564 10859 1925 Fail 0.0206 538 10436 1939 Fail 0.0209 511 10082 1972 Fail 0.0212 488 9727 1993 Fail 0.0215 465 9372 2015 Fail 0.0218 447 9070 2029 Fail 0.0221 435 8767 2015 Fail 0.0223 412 8480 2058 Fail 0.0226 399 8169 2047 Fail 0.0229 375 7905 2108 Fail 0.0232 360 7649 2124 Fail 0.0235 343 7406 2159 Fail 0.0238 326 7136 2188 Fail 0.0241 309 6910 2236 Fail 0.0244 292 6720 2301 Fail 0.0246 279 6495 2327 Fail 0.0249 264 6267 2373 Fail 0.0252 254 6078 2392 Fail 0.0255 237 5870 2476 Fail 0.0258 225 5680 2524 Fail 0.0261 214 5489 2564 Fail 0.0264 203 5308 2614 Fail 0.0266 186 5140 2763 Fail 0.0269 176 4968 2822 Fail 0.0272 166 4799 2890 Fail 0.0275 156 4663 2989 Fail 0.0278 139 4514 3247 Fail 0.0281 128 4383 3424 Fail 0.0284 120 4237 3530 Fail 0.0287 112 4121 3679 Fail 0.0289 99 3982 4022 Fail 0.0292 93 3871 4162 Fail 0.0295 84 3721 4429 Fail 0.0298 79 3620 4582 Fail 0.0301 77 3505 4551 Fail 0.0304 73 3399 4656 Fail 0.0307 66 3302 5003 Fail 0.0310 61 3214 5268 Fail 0.0312 54 3110 5759 Fail 0.0315 47 3004 6391 Fail 0.0318 43 2905 6755 Fail 0.0321 39 2819 7228 Fail 0.0324 36 2724 7566 Fail 0.0327 34 2642 7770 Fail 0.0330 31 2576 8309 Fail Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -17- 0.0332 29 2510 8655 Fail 0.0335 27 2447 9062 Fail 0.0338 27 2380 8814 Fail 0.0341 25 2296 9184 Fail 0.0344 21 2225 10595 Fail 0.0347 21 2151 10242 Fail 0.0350 19 2097 11036 Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0 acre-feet On-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. Off-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. LID Report LID Technique Used for Total Volume Volume Infiltration Cumulative Percent Water Quality Percent Comment Treatment? Needs Through Volume Volume Volume Water Quality Treatment Facility (ac-ft.) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit Tank 1 POC N 133.36 N 0.00 Total Volume Infiltrated 133.36 0.00 0.00 0.00 0.00 0% No Treat. Credit Compliance with LID Standard 8 Duration Analysis Result = Failed POC #2 was not reported because POC must exist in both scenarios and both scenarios must have been run.Perind and Impind Changes No changes have been made. This program and accompanying documentation are provided 'as -is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by Clear Creek Solutions, Inc. 2005-2021; All Rights Reserved. Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -18- WWHM-2-DETENTION SIZING WWHM2012 PROJECT REPORT Project Name: Kisan detention pipe Site Name: Kisan Enterprises Site Address: 22810 Edmonds Way City : Edmonds Report Date: 4/21/2021 MGS Regoin Puget East Data Start 1901/10/1 Data End : 2058/09/30 DOT Data Number: 03 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 Low Flow Threshold for POC 2 : 50 Percent of the 2 Year High Flow Threshold for POC 2: 50 year PREDEVELOPED LAND USE Name : Ex Subbasin-1 Bypass: No Groundwater: No Pervious Land Use acre C, Forest, Mod .51 Pervious Total 0.51 Impervious Land Use acre Impervious Total 0 Basin Total 0.51 Element Flows To: Surface Interflow Insight Engineering Co. - Stormwater Site Plan Groundwater 5/20/21 REVISION May 20 2021 DEPARTMENT -19- Name : E Subbasin-2 Bypass: No Groundwater: No Pervious Land Use acre C, Forest, Mod .26 Pervious Total 26 Impervious Land Use acre Impervious Total 0 Basin Total 0.26 Element Flows To: Surface Interflow Groundwater MITIGATED LAND USE Name : Dev Subbasin-1 Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Mod .21 Pervious Total 0.21 Impervious Land Use acre ROADS FLAT 0.2 ROOF TOPS FLAT 0.09 SIDEWALKS FLAT 0.01 Impervious Total 0.3 Basin Total 0.51 Element Flows To: Surface Interflow Groundwater Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEPARTMENT -20- Tank 1 Tank 1 Name Dev Subbasin-2 Bypass: Groundwater: N Pervious Land Use \ acre C, Lawn, Mod .02 Pervious Total �O2 Impervious Land Use acre ROADS MOD 0.04 ROOF TOPS FLAT 0.2 Impervious Total 0.24 Basin Total 0.26 Element Flows To: Surface Interflow Name : Tank 1 Tank Name: Tank 1 Depth: 9 ft. Tank Type Circular Diameter 9 ft. Length : 130 ft. Discharge Structure Riser Height: 8 ft. Riser Diameter: 12 in. Notch Type: Rectangular Notch Width: 0.016 ft. Notch Height: 0.540 ft. Orifice 1 Diameter: 0.26 in Element Flows To: Outlet 1 Outlet 2 Elevation: 0 ft. Tank Hydraulic Table Insight Engineering Co. - Stormwater Site Plan Groundwater 5/20/21 REVISION May 20 2021 DEPARTMENT -21- Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.000 0.000 0.000 0.000 0.1000 0.005 0.000 0.000 0.000 0.2000 0.007 0.001 0.000 0.000 0.3000 0.009 0.001 0.001 0.000 0.4000 0.011 0.003 0.001 0.000 0.5000 0.012 0.004 0.001 0.000 0.6000 0.013 0.005 0.001 0.000 0.7000 0.014 0.006 0.001 0.000 0.8000 0.015 0.008 0.001 0.000 0.9000 0.016 0.009 0.001 0.000 1.0000 0.016 0.011 0.001 0.000 1.1000 0.017 0.013 0.001 0.000 1.2000 0.018 0.015 0.002 0.000 1.3000 0.018 0.016 0.002 0.000 1.4000 0.019 0.018 0.002 0.000 1.5000 0.020 0.020 0.002 0.000 1.6000 0.020 0.022 0.002 0.000 1.7000 0.021 0.024 0.002 0.000 1.8000 0.021 0.027 0.002 0.000 1.9000 0.021 0.029 0.002 0.000 2.0000 0.022 0.031 0.002 0.000 2.1000 0.022 0.033 0.002 0.000 2.2000 0.023 0.036 0.002 0.000 2.3000 0.023 0.038 0.002 0.000 2.4000 0.023 0.040 0.002 0.000 2.5000 0.024 0.043 0.002 0.000 2.6000 0.024 0.045 0.003 0.000 2.7000 0.024 0.047 0.003 0.000 2.8000 0.024 0.050 0.003 0.000 2.9000 0.025 0.052 0.003 0.000 3.0000 0.025 0.055 0.003 0.000 3.1000 0.025 0.057 0.003 0.000 3.2000 0.025 0.060 0.003 0.000 3.3000 0.025 0.063 0.003 0.000 3.4000 0.026 0.065 0.003 0.000 3.5000 0.026 0.068 0.003 0.000 3.6000 0.026 0.070 0.003 0.000 3.7000 0.026 0.073 0.003 0.000 3.8000 0.026 0.076 0.003 0.000 3.9000 0.026 0.078 0.003 0.000 4.0000 0.026 0.081 0.003 0.000 4.1000 0.026 0.084 0.003 0.000 4.2000 0.026 0.086 0.003 0.000 4.3000 0.026 0.089 0.003 0.000 4.4000 0.026 0.092 0.003 0.000 4.5000 0.026 0.094 0.003 0.000 4.6000 0.026 0.097 0.003 0.000 4.7000 0.026 0.100 0.004 0.000 4.8000 0.026 0.103 0.004 0.000 4.9000 0.026 0.105 0.004 0.000 5.0000 0.026 0.108 0.004 0.000 5.1000 0.026 0.111 0.004 0.000 5.2000 0.026 0.113 0.004 0.000 5.3000 0.026 0.116 0.004 0.000 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -22- 5.4000 0.026 0.118 0.004 0.000 5.5000 0.026 0.121 0.004 0.000 5.6000 0.026 0.124 0.004 0.000 5.7000 0.025 0.126 0.004 0.000 5.8000 0.025 0.129 0.004 0.000 5.9000 0.025 0.131 0.004 0.000 6.0000 0.025 0.134 0.004 0.000 6.1000 0.025 0.137 0.004 0.000 6.2000 0.024 0.139 0.004 0.000 6.3000 0.024 0.142 0.004 0.000 6.4000 0.024 0.144 0.004 0.000 6.5000 0.024 0.146 0.004 0.000 6.6000 0.023 0.149 0.004 0.000 6.7000 0.023 0.151 0.004 0.000 6.8000 0.023 0.153 0.004 0.000 6.9000 0.022 0.156 0.004 0.000 7.0000 0.022 0.158 0.004 0.000 7.1000 0.021 0.160 0.004 0.000 7.2000 0.021 0.162 0.004 0.000 7.3000 0.021 0.165 0.005 0.000 7.4000 0.020 0.167 0.005 0.000 7.5000 0.020 0.169 0.005 0.000 7.6000 0.019 0.171 0.007 0.000 7.7000 0.018 0.173 0.011 0.000 7.8000 0.018 0.174 0.015 0.000 7.9000 0.017 0.176 0.019 0.000 8.0000 0.016 0.178 0.024 0.000 8.1000 0.016 0.180 0.357 0.000 8.2000 0.015 0.181 0.931 0.000 8.3000 0.014 0.183 1.533 0.000 8.4000 0.013 0.184 1.984 0.000 8.5000 0.012 0.185 2.227 0.000 8.6000 0.011 0.186 2.463 0.000 8.7000 0.009 0.187 2.659 0.000 8.8000 0.007 0.188 2.841 0.000 8.9000 0.005 0.189 3.012 0.000 9.0000 0.000 0.189 3.174 0.000 9.1000 0.000 0.000 3.327 0.000 ANALYSIS RESULTS Stream Protection Duration Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.51 Total Impervious Area:O Mitigated Landuse Totals for POC #1 Total Pervious Area:0.21 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -23- Total Impervious Area:0.3 Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.0087 5 year 0.014445 10 year 0.017706 25 year 0.021105 50 year 0.023161 100 year 0.024869 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.003921 5 year 0.006557 10 year 0.00913 25 year 0.013661 50 year 0.018231 100 year 0.024097 Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1902 0.012 0.004 1903 0.004 0.003 1904 0.011 0.003 1905 0.005 0.004 1906 0.002 0.003 1907 0.014 0.004 1908 0.008 0.003 1909 0.009 0.004 1910 0.016 0.004 1911 0.008 0.004 1912 0.033 0.004 1913 0.013 0.004 1914 0.003 0.003 1915 0.004 0.004 1916 0.007 0.003 1917 0.003 0.003 1918 0.008 0.005 1919 0.006 0.003 1920 0.008 0.003 1921 0.008 0.004 1922 0.009 0.004 1923 0.008 0.004 1924 0.004 0.003 1925 0.004 0.003 1926 0.007 0.003 1927 0.009 0.004 1928 0.006 0.004 1929 0.015 0.004 1930 0.008 0.004 1931 0.008 0.004 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -24- 1932 0.006 0.004 1933 0.007 0.004 1934 0.021 0.059 1935 0.007 0.005 1936 0.011 0.004 1937 0.010 0.003 1938 0.009 0.004 1939 0.000 0.003 1940 0.007 0.004 1941 0.007 0.003 1942 0.011 0.020 1943 0.004 0.004 1944 0.011 0.004 1945 0.008 0.004 1946 0.008 0.003 1947 0.005 0.003 1948 0.018 0.004 1949 0.015 0.005 1950 0.008 0.004 1951 0.009 0.004 1952 0.030 0.005 1953 0.024 0.005 1954 0.007 0.004 1955 0.006 0.003 1956 0.004 0.003 1957 0.010 0.004 1958 0.024 0.010 1959 0.014 0.014 1960 0.005 0.003 1961 0.014 0.011 1962 0.007 0.004 1963 0.003 0.003 1964 0.007 0.003 1965 0.017 0.044 1966 0.003 0.003 1967 0.007 0.003 1968 0.009 0.004 1969 0.006 0.004 1970 0.011 0.004 1971 0.018 0.009 1972 0.012 0.004 1973 0.014 0.004 1974 0.009 0.004 1975 0.022 0.009 1976 0.009 0.004 1977 0.005 0.003 1978 0.017 0.022 1979 0.004 0.003 1980 0.008 0.004 1981 0.008 0.004 1982 0.006 0.004 1983 0.014 0.004 1984 0.004 0.003 1985 0.008 0.004 1986 0.006 0.004 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -25- 1987 0.014 0.005 1988 0.010 0.004 1989 0.008 0.003 1990 0.010 0.004 1991 0.008 0.004 1992 0.012 0.005 1993 0.010 0.004 1994 0.017 0.004 1995 0.004 0.003 1996 0.020 0.018 1997 0.009 0.004 1998 0.008 0.004 1999 0.000 0.002 2000 0.006 0.004 2001 0.004 0.003 2002 0.017 0.004 2003 0.009 0.004 2004 0.010 0.004 2005 0.015 0.004 2006 0.006 0.004 2007 0.007 0.004 2008 0.009 0.004 2009 0.005 0.003 2010 0.004 0.004 2011 0.005 0.004 2012 0.008 0.003 2013 0.006 0.003 2014 0.004 0.003 2015 0.019 0.003 2016 0.002 0.003 2017 0.015 0.005 2018 0.027 0.069 2019 0.029 0.013 2020 0.010 0.004 2021 0.011 0.005 2022 0.004 0.003 2023 0.009 0.004 2024 0.037 0.004 2025 0.007 0.004 2026 0.013 0.004 2027 0.006 0.003 2028 0.003 0.003 2029 0.009 0.004 2030 0.020 0.004 2031 0.005 0.003 2032 0.004 0.003 2033 0.004 0.003 2034 0.005 0.003 2035 0.021 0.040 2036 0.011 0.004 2037 0.002 0.003 2038 0.013 0.004 2039 0.001 0.003 2040 0.004 0.004 2041 0.006 0.003 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -26- 2042 0.023 0.016 2043 0.010 0.005 2044 0.013 0.004 2045 0.008 0.004 2046 0.010 0.022 2047 0.006 0.004 2048 0.008 0.003 2049 0.008 0.004 2050 0.005 0.003 2051 0.008 0.004 2052 0.005 0.004 2053 0.008 0.008 2054 0.016 0.004 2055 0.003 0.003 2056 0.003 0.003 2057 0.005 0.004 2058 0.007 0.004 Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated Rank Predeveloped Mitigated 1 0.0367 0.0687 2 0.0328 0.0595 3 0.0299 0.0444 4 0.0291 0.0399 5 0.0273 0.0220 6 0.0242 0.0218 7 0.0240 0.0200 8 0.0226 0.0175 9 0.0217 0.0161 10 0.0209 0.0143 11 0.0206 0.0128 12 0.0203 0.0108 13 0.0197 0.0104 14 0.0191 0.0091 15 0.0183 0.0089 16 0.0175 0.0076 17 0.0174 0.0049 18 0.0173 0.0049 19 0.0166 0.0048 20 0.0165 0.0046 21 0.0161 0.0046 22 0.0159 0.0046 23 0.0152 0.0046 24 0.0151 0.0046 25 0.0150 0.0046 26 0.0147 0.0045 27 0.0144 0.0045 28 0.0144 0.0045 29 0.0140 0.0045 30 0.0138 0.0044 31 0.0137 0.0044 32 0.0136 0.0044 33 0.0133 0.0044 Insight Engineering Co. - Stormwater Site Plan POC #1 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -27- 34 0.0131 0.0043 35 0.0128 0.0043 36 0.0127 0.0042 37 0.0120 0.0042 38 0.0119 0.0042 39 0.0119 0.0042 40 0.0114 0.0041 41 0.0114 0.0041 42 0.0113 0.0041 43 0.0111 0.0041 44 0.0111 0.0041 45 0.0110 0.0041 46 0.0105 0.0041 47 0.0104 0.0041 48 0.0103 0.0040 49 0.0102 0.0040 50 0.0101 0.0040 51 0.0100 0.0040 52 0.0099 0.0040 53 0.0098 0.0040 54 0.0095 0.0040 55 0.0095 0.0040 56 0.0094 0.0040 57 0.0093 0.0040 58 0.0093 0.0040 59 0.0092 0.0040 60 0.0092 0.0040 61 0.0091 0.0039 62 0.0091 0.0039 63 0.0091 0.0039 64 0.0090 0.0039 65 0.0089 0.0039 66 0.0088 0.0039 67 0.0087 0.0039 68 0.0086 0.0039 69 0.0085 0.0039 70 0.0084 0.0039 71 0.0084 0.0039 72 0.0084 0.0039 73 0.0083 0.0039 74 0.0083 0.0039 75 0.0083 0.0038 76 0.0082 0.0038 77 0.0081 0.0038 78 0.0080 0.0038 79 0.0080 0.0038 80 0.0080 0.0038 81 0.0080 0.0038 82 0.0079 0.0037 83 0.0079 0.0037 84 0.0079 0.0037 85 0.0079 0.0037 86 0.0078 0.0037 87 0.0078 0.0037 88 0.0076 0.0037 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -28- 89 0.0076 0.0037 90 0.0076 0.0037 91 0.0075 0.0037 92 0.0074 0.0036 93 0.0074 0.0036 94 0.0073 0.0036 95 0.0072 0.0036 96 0.0071 0.0036 97 0.0070 0.0036 98 0.0068 0.0036 99 0.0068 0.0036 100 0.0067 0.0036 101 0.0067 0.0036 102 0.0066 0.0035 103 0.0066 0.0035 104 0.0065 0.0035 105 0.0064 0.0035 106 0.0064 0.0035 107 0.0062 0.0035 108 0.0062 0.0035 109 0.0061 0.0035 110 0.0061 0.0035 111 0.0060 0.0035 112 0.0059 0.0035 113 0.0058 0.0035 114 0.0058 0.0034 115 0.0056 0.0034 116 0.0056 0.0034 117 0.0056 0.0034 118 0.0054 0.0034 119 0.0054 0.0034 120 0.0053 0.0034 121 0.0052 0.0033 122 0.0051 0.0033 123 0.0051 0.0033 124 0.0050 0.0033 125 0.0050 0.0033 126 0.0049 0.0033 127 0.0049 0.0033 128 0.0046 0.0032 129 0.0044 0.0032 130 0.0044 0.0032 131 0.0043 0.0032 132 0.0042 0.0032 133 0.0042 0.0032 134 0.0042 0.0032 135 0.0041 0.0032 136 0.0041 0.0031 137 0.0039 0.0031 138 0.0039 0.0031 139 0.0039 0.0031 140 0.0038 0.0031 141 0.0038 0.0031 142 0.0037 0.0031 143 0.0035 0.0031 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -29- 144 0.0035 0.0030 145 0.0033 0.0030 146 0.0033 0.0030 147 0.0032 0.0030 148 0.0032 0.0030 149 0.0030 0.0030 150 0.0030 0.0029 151 0.0027 0.0029 152 0.0023 0.0029 153 0.0018 0.0029 154 0.0018 0.0028 155 0.0007 0.0027 156 0.0004 0.0026 157 0.0001 0.0025 Stream Protection Duration POC #1 The Facility PASSED The Facility PASSED. Flow(cfs) Predev Mit Percentage Pass/Fail 0.0044 12741 9570 75 Pass 0.0045 11572 5872 50 Pass 0.0047 10526 3487 33 Pass 0.0049 9594 1735 18 Pass 0.0051 8782 1002 11 Pass 0.0053 8066 866 10 Pass 0.0055 7428 748 10 Pass 0.0057 6845 716 10 Pass 0.0059 6295 691 10 Pass 0.0061 5809 667 11 Pass 0.0063 5325 641 12 Pass 0.0064 4899 617 12 Pass 0.0066 4509 591 13 Pass 0.0068 4166 576 13 Pass 0.0070 3845 554 14 Pass 0.0072 3544 531 14 Pass 0.0074 3273 505 15 Pass 0.0076 3026 482 15 Pass 0.0078 2803 460 16 Pass 0.0080 2614 437 16 Pass 0.0082 2441 425 17 Pass 0.0083 2290 402 17 Pass 0.0085 2118 387 18 Pass 0.0087 1985 367 18 Pass 0.0089 1866 357 19 Pass 0.0091 1762 347 19 Pass 0.0093 1652 337 20 Pass 0.0095 1562 325 20 Pass 0.0097 1478 312 21 Pass 0.0099 1393 305 21 Pass 0.0101 1324 289 21 Pass 0.0102 1242 273 21 Pass Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -30- 0.0104 1172 261 22 Pass 0.0106 1119 250 22 Pass 0.0108 1053 243 23 Pass 0.0110 1000 236 23 Pass 0.0112 953 224 23 Pass 0.0114 901 220 24 Pass 0.0116 868 214 24 Pass 0.0118 833 206 24 Pass 0.0120 799 197 24 Pass 0.0121 774 191 24 Pass 0.0123 740 186 25 Pass 0.0125 717 183 25 Pass 0.0127 688 174 25 Pass 0.0129 658 166 25 Pass 0.0131 630 162 25 Pass 0.0133 598 151 25 Pass 0.0135 563 149 26 Pass 0.0137 538 145 26 Pass 0.0139 511 139 27 Pass 0.0140 487 134 27 Pass 0.0142 464 131 28 Pass 0.0144 447 124 27 Pass 0.0146 434 116 26 Pass 0.0148 412 111 26 Pass 0.0150 399 106 26 Pass 0.0152 375 99 26 Pass 0.0154 360 97 26 Pass 0.0156 343 94 27 Pass 0.0158 326 92 28 Pass 0.0159 309 87 28 Pass 0.0161 292 84 28 Pass 0.0163 279 78 27 Pass 0.0165 264 76 28 Pass 0.0167 254 75 29 Pass 0.0169 237 72 30 Pass 0.0171 224 72 32 Pass 0.0173 214 67 31 Pass 0.0175 203 65 32 Pass 0.0177 185 60 32 Pass 0.0178 176 58 32 Pass 0.0180 166 58 34 Pass 0.0182 155 56 36 Pass 0.0184 139 55 39 Pass 0.0186 128 54 42 Pass 0.0188 120 52 43 Pass 0.0190 112 49 43 Pass 0.0192 99 47 47 Pass 0.0194 93 46 49 Pass 0.0196 84 43 51 Pass 0.0197 79 41 51 Pass 0.0199 77 40 51 Pass 0.0201 73 34 46 Pass 0.0203 66 32 48 Pass 0.0205 61 32 52 Pass 0.0207 53 31 58 Pass Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -31- 0.0209 47 30 63 Pass 0.0211 43 28 65 Pass 0.0213 39 26 66 Pass 0.0215 36 25 69 Pass 0.0216 34 23 67 Pass 0.0218 31 21 67 Pass 0.0220 29 20 68 Pass 0.0222 27 20 74 Pass 0.0224 27 20 74 Pass 0.0226 25 18 72 Pass 0.0228 21 18 85 Pass 0.0230 21 17 80 Pass 0.0232 19 16 84 Pass Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0 acre-feet On-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. Off-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. LID Report LID Technique Used for Total Volume Volume Infiltration Cumulative Percent Water Quality Percent Comment Treatment? Needs Through Volume Volume Volume Water Quality Treatment Facility (ac-ft.) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit Tank 1 POC N 133.36 N 0.00 Total Volume Infiltrated 133.36 0.00 0.00 0.00 0.00 0% No Treat. Credit Compliance with LID Standard 8 Duration Analysis Result = Failed Stream Protection Duration Predeveloped Landuse-TQtals for POC #2 Total Pervious Area:0.26 Total Impervious Area:O Mitigated Landuse Totals for POC #2 Total Pervious Area:0.02 Total Impervious Area:0.24 Flow Frequency Return Periods for Predeveloped. POC #2 Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -32- Return Period Flow(cfs) 2 year 0.004435 5 year 0.007364 10 year 0.009026 25 year 0.01076 50 year 0.011807 100 year 0.012678 REVISION May 20 2021 DEPARTMENT Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 y 0.061331 5 year 1317 10 year �5705 25 year 52 50 year 0.130825 100 year 0.147304 The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. Water Quality BMP Flow and Volume for POC #2 On-line facility volume: 0 acre-feet On-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cis. Off-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. LID Report LID Technique Used for Total Volume Volume Infiltration Cumulative Percent Water Quality Percent Comment Treatment? Needs Through Volume Volume Volume Water Quality Treatment Facility (ac-ft.) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit Total Volume Infiltrated 0.00 0.00 0.00 0.00 0.00 0% No Treat. Credit Compliance with LID Standard 8 Duration Analysis Result = Failed Perind and Impind Changes No changes have been made. This program and accompanying documentation are provided 'as -is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and Insight Engineering Co. - Stormwater Site Plan 5/20/21 -33- accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by Clear Creek Solutions, Inc. 2005-2021; All Rights Reserved. Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 ol DEVELOPRVICES DEPARTMENT -34- APPENDIX A- STORMFILTER SIZING SHEET AND GULD APPROVAL Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEPARTMENT -35- REVISION May 20 2021 DEPARTMENT 05w,*-NTECH' ENGINEERED SOLUTIONS Project Name: Kisan Enterprises Site Designation: CB #4 Date: 12/1/20 County or Independent City: Edmonds Designer: SKJ State: WA Flow Based Data: Peak Design Flow (cfs) 0.21 Water Quality Flow (cfs) JFrom original approved drainage report. 0.02 Annual Rainfall (inches) 36 Total Drainage Area, A (ac) 0.21 Post Development Impervious Area, A, (ac) 0.21 Pervious Area, Ap (ac) 0.00 % Impervious 100% Runoff Coefficient, Rc 0.95 Flow Based Filter Sizing: Filter Type Structure Type Cartridge Height Media Type Cartridge Flow Rate, gpm/sf Storm Filter Catchbasin (Ste 27" ZPG 1.00 gpm/sf Cartridges Required 1 1 Recommended Model I SFCB1 Maximum Water Quality Flow 1 0.03 cfs wlm� WA SH IN GT0N STATE EECAO LE0 C GY April 2017 GENERAL USE LEVEL DESIGNATION FOR BASIC (TSS) TREATMENT For CONTECH Engineered Solutions Stormwater Management StormFilter® With ZPG Media at 1 gpm/sq ft media surface area Ecology's Decision: Based on the CONTECH Engineered Solutions' (CONTECH) application submissions, Ecology hereby issues a General Use Level Designation (GULD) for the Stormwater Management StormFilter® (StormFilter): As a basic stormwater treatment practice for total suspended solids (TSS) removal, • Using ZPGTM media (zeolite/perlite/granular activated carbon), with the size distribution described below, • Sized at a hydraulic loading rate of 1 gpm/ft2 of media surface area, per Table 1, and • Internal bypassing needs to be consistent with the design guidelines in CONTECH's current product design manual. Table 1. StormFilter Design Flow Rates per Cartridge Effective Cartridge Height (inches) 12 18 27 Cartridge Flow Rate (pm/cartrid e) 5 7.5 11.3 2. Ecology approves StormFilter systems containing ZPGTM media for treatment at the hydraulic loading rates shown in Table 1, and sized based on the water quality design flow rate for an off-line system. Contech designs their StormFilter systems to maintain treatment of the water quality design flow while routing excess flows around the treatment chamber during periods of peak bypass. The water quality design flow rates are calculated using the following procedures: • Western Washington: For treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using the latest version of the Western Washington Hydrology Model or other Ecology -approved continuous runoff model. REVISION May20 2021 D DEVELOPRVICES DEPARTMENT CONTECH - StormFilter® GULD Maintenance Update (November 2012) Page 11 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT • Eastern Washington: For treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using one of the three methods described in Chapter 2.2.5 of the Stormwater Management Manual for Eastern Washington (SWMMEW) or local manual. • Entire State: For treatment installed downstream of detention, the water quality design flow rate is the full 2-year release rate of the detention facility. 3. This designation has no expiration date, but Ecology may amend or revoke it. Ecology's Conditions of Use: The StormFilter with ZPG media shall comply with the following conditions: 1. Design, install, operate, and maintain the StormFilter with ZPG media in accordance with applicable Contech Engineered Solutions manuals, documents, and the Ecology Decision. 2. Install StormFilter systems to bypass flows exceeding the water quality treatment rate. Additionally, high flows will not re -suspend captured sediments. Design StormFilter systems in accordance with the performance goals in Ecology's most recent Stormwater Manual and CONTECH's Product Design Manual Version 4.1 (April 2006), or most current version, unless otherwise specified. 3. Owners must follow the design, pretreatment, land use application, and maintenance criteria in CONTECH's Design Manual. 4. Pretreatment of TSS and oil and grease may be necessary, and designers shall provide pre-treatment in accordance with the most current versions of the CONTECH's Product Design Manual (April 2006) or the applicable Ecology Stormwater Manual. Design pre-treatment using the performance criteria and pretreatment practices provided on Ecology's "Evaluation of Emerging Stormwater Treatment Technologies" website. 5. Maintenance: The required maintenance interval for stormwater treatment devices is often dependent upon the degree of pollutant loading from a particular drainage basin. Therefore, Ecology does not endorse or recommend a "one size fits all" maintenance cycle for a particular model/size of manufactured filter treatment device. Typically, CONTECH designs StormFilter systems for a target filter media replacement interval of 12 months. Maintenance includes removing accumulated sediment from the vault, and replacing spent cartridges with recharged cartridges. CONTECH - StormFilter® GULD Maintenance Update (November 2012) Page 12 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT Indications of the need for maintenance include effluent flow decreasing to below the design flow rate, as indicated by the scumline above the shoulder of the cartridge. Owners/operators must inspect StormFilter with ZPG media for a minimum of twelve months from the start of post -construction operation to determine site -specific maintenance schedules and requirements. You must conduct inspections monthly during the wet season, and every other month during the dry season. (According to the SWMMWW, the wet season in western Washington is October 1 to April 30. According to SWMMEW, the wet season in eastern Washington is October 1 to June 30). After the first year of operation, owners/operators must conduct inspections based on the findings during the first year of inspections. • Conduct inspections by qualified personnel, follow manufacturer's guidelines, and use methods capable of determining either a decrease in treated effluent flowrate and/or a decrease in pollutant removal ability. When inspections are performed, the following findings typically serve as maintenance triggers: • Accumulated vault sediment depths exceed an average of 2 inches, or • Accumulated sediment depths on the tops of the cartridges exceed an average of 0.5 inches, or • Standing water remains in the vault between rain events, or • Bypass occurs during storms smaller than the design storm. Note: If excessive floatables (trash and debris) are present, perform a minor maintenance consisting of gross solids removal, not cartridge replacement. 6. CONTECH shall maintain readily available reports listed under "Application Documents" (above) as public, as well as the documentation submitted with its previous conditional use designation application. CONTECH shall provide links to this information from its corporate website, and make this information available upon request, at no cost and in a timely manner. 7. ZPGTM media used shall conform with the following specifications: Each cartridge contains a total of approximately 2.6 cubic feet of media. The ZPGTm cartridge consists of an outer layer of perlite that is approximately 1.3 cubic feet in volume and an inner layer, consisting of a mixture of 90% zeolite and 10% granular activated carbon, which is approximately 1.3 cubic feet in volume. Perlite Media: Perlite media shall be made of natural siliceous volcanic rock free of any debris or foreign matter. The expanded perlite shall CONTECH - StormFilter® GULD Maintenance Update (November 2012) Page 13 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT have a bulk density ranging from 6.5 to 8.5 lbs per cubic foot and particle sizes ranging from 0.09" (#8 mesh) to 0.38" (3/8" mesh). Zeolite Media: Zeolite media shall be made of naturally occurring clinoptilolite. The zeolite media shall have a bulk density ranging from 44 to 50 lbs per cubic foot and particle sizes ranging from 0.13" (#6 mesh) to 0.19" (#4 mesh). Additionally, the cation exchange capacity (CEC) of zeolite shall range from approximately 1.0 to 2.2 meq/g. Granular Activated Carbon: Granular activated carbon (GAC) shall be made of lignite coal that has been steam -activated. The GAC media shall have a bulk density ranging from 28 to 31 lbs per cubic foot and particle sizes ranging from a 0.09" (#8 mesh) to 0.19" (#4 mesh). Approved Alternate Configurations Peak Diversion StormFilter 1. The Peak Diversion StormFilter allows for off-line bypass within the StormFilter structure. Design capture flows and peak flows enter the inlet bay which contains an internal weir. The internal weir allows design flows to enter the cartridge bay through a transfer hole located at the bottom of the inlet bay while the unit routs higher flows around the cartridge bay. 2. To select the size of the Peak Diversion StormFilter unit, the designer must determine the number of cartridges required and size of the standard StormFilter using the site - specific water quality design flow and the StormFilter Design Flow Rates per Cartridge as described above. 3. New owners may not install the Peak Diversion StormFilter at an elevation or in a location where backwatering may occur. Applicant: Contech Engineered Solutions Applicant's Address: 11835 NE Glenn Widing Dr. Portland, OR 97220 Application Documents: The applicant's master report, titled, "The Stormwater Management StormFilter Basic Treatment Application for General Use Level Designation in Washington", Stormwater Management, Inc., November 1, 2004, includes the following reports: • (Public) Evaluation of the Stormwater Management StormFilter Treatment System: Data Validation Report and Summary of the Technical Evaluation Engineering Report (TEER) by Stormwater Management Inc., October 29, 2004 Ecology's technology assessment protocol requires the applicant to hire an independent consultant to complete the following work: CONTECH - StormFilter® GULD Maintenance Update (November 2012) Page 14 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT 1. Complete the data validation report. 2. Prepare a TEER summary, including a testing summary and conclusions compared with the supplier's performance claims. 3. Provide a recommendation of the appropriate technology use level. 4. Work with Ecology to post recommend relevant information on Ecology's website. 5. Provide additional testing recommendations, if needed." 6. This report, authored by Dr. Gary Minton, Ph. D., P.E., Resource Planning Associates, satisfies the Ecology requirement. • (Public) "Performance of the Stormwater Management StormFilter Relative to the Washington State Department of Ecology Performance Goals for Basic Treatment," is a summary of StormFilter performance that strictly adheres to the criteria listed in the Guidance for Evaluating Emerging Stormwater Treatment Technologies, Technology Assessment Protocol — Ecology (TAPE). • "Heritage Marketplace Field Evaluation: Stormwater Management StormFilter with ZPGTM Media," is a report showing all of the information collected at Site A as stated in the SMI Quality Assurance Project Plan (QAPP). This document contains detailed information regarding each storm event collected at this site, and it provided a detailed overview of the data and project. • "Lake Stevens Field Evaluation: Stormwater Management StormFilter with ZPGTM Media," is a report that corresponds to Site E as stated in the SMI QAPP. This document contains detailed information regarding each storm collected at this site, and includes a detailed overview of the data and project. • (Public) "Evaluation of the Stormwater Management StormFilter for the removal of SIL-CO-SIL 106, a standardized silica product: ZPGTM at 7.5 GPM" is a report that describes laboratory testing at full design flow. • "Factors Other Than Treatment Performance." • 'State of Washington Installations." • "Peak Diversion StormFilter" is a technical document demonstrating the Peak Diversion StormFilter system complies with the Stormwater Management Manual for Western Washington Volume V Section 4.5.1. Above -listed documents noted as "public" are available by contacting CONTECH. Applicant's Use Level Request: That Ecology grant a General Use Level Designation for Basic Treatment for the StormFilter using ZPGTM media (zeolite/perlite/granular activated carbon) at a hydraulic loading rate of 1 gpm/ft2 of media surface area in accordance with Ecology's 2011 Technical Guidance Manual for Evaluating Emerging Stormwater Treatment Technologies Technology Assessment Protocol — Ecology (TAPE). CONTECH - StormFilter® GULD Maintenance Update (November 2012) Page 15 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT Applicant's Performance Claim: The combined data from the two field sites reported in the TER (Heritage Marketplace and Lake Stevens) indicate that the performance of a StormFilter system configured for inline bypass with ZPGTM media and a hydraulic loading rate of 1 gpm/ft2 of media surface area meets Ecology performance goals for Basic Treatment. Ecology's Recommendations: Based on the weight of the evidence and using its best professional judgment, Ecology finds that: • StormFilter, using ZPGTM media and operating at a hydraulic loading rate of no more than 1 gpm/ft2 of media surface area, is expected to provide effective stormwater treatment achieving Ecology's Basic Treatment (TSS removal) performance goals. Contech demonstrated this is through field and laboratory testing performed in accordance with the approved protocol. StormFilter is deemed satisfactory with respect to factors other than treatment performance (e.g., maintenance; see the protocol's Appendix B for complete list). Findings of Fact: • Influent TSS concentrations and particle size distributions were generally within the range of what Ecology considers "typical" for western Washington (silt -to -silt loam). • Contech sampled thirty-two (32) storm events at two sites for storms from April 2003 to March 2004, of which Contech deemed twenty-two (22) as "qualified" and were therefore included in the data analysis set. • Statistical analysis of these 22 storm events verifies the data set's adequacy. • Analyzing all 22 qualifying events, the average influent and effluent concentrations and aggregate pollutant load reduction are 114 mg/L, 25 mg/L, and 82%, respectively. • Analyzing all 22 qualifying events based on the estimated average flow rate during the event (versus the measured peak flow rate), and more heavily weighting those events near the design rate (versus events either far above or well below the design rate) does not significantly affect the reported results. • For the 7 qualifying events with influent TSS concentrations greater than 100 mg/L, the average influent and effluent concentrations and aggregate pollutant load reduction are 241 mg/L, 34 mg/L, and 89%, respectively. If we exclude the 2 of 7 events that exceed the maximum 300 mg/L specified in Ecology's guidelines, the average influent and effluent concentrations and aggregate pollutant load reduction are 158 mg/L, 35 mg/L, and 78%, respectively. • For the 15 qualifying events with influent TSS concentrations less than 100 mg/L, the average influent and effluent concentrations and aggregate pollutant load reduction are 55 mg/L, 20 mg/L, and 61%, respectively. If the 6 of 15 events that fall below the minimum 33 mg/L TSS specified in Ecology's guidelines are excluded, the average CONTECH - StormFilter® GULD Maintenance Update (November 2012) Page 16 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT influent and effluent concentrations and aggregate pollutant load reduction are 78 mg/L, 26 mg/L, and 67%, respectively. • For the 8 qualifying events with peak discharge exceeding design flow (ranging from 120 to 257% of the design rate), results ranged from 52% to 96% TSS removal, with an average of 72%. • Due to the characteristics of the hydrographs, the field results generally reflect flows below (ranging between 20 and 60 percent of) the tested facilities' design rate. During these sub -design flow rate periods, some of the cartridges operate at or near their individual full design flow rate (generally between 4 and 7.5 GPM for an 18" cartridge effective height) because their float valves have opened. Float valves remain closed on the remaining cartridges, which operate at their base "trickle" rate of 1 to 1.5 GPM. • Laboratory testing using U.S. Silica's Sil-Co-Sil 106 fine silica product showed an average 87% TSS removal for testing at 7.5 GPM per cartridge (100% design flow rate). • Other relevant testing at I-5 Lake Union, Greenville Yards (New Jersey), and Ski Run Marina (Lake Tahoe) facilities shows consistent TSS removals in the 75 to 85% range. Note that the evaluators operated the 1-5 Lake Union at 50%, 100%, and 125% of design flow. • SMI's application included a satisfactory "Factors other than treatment performance" discussion. Note: Ecology's 80% TSS removal goal applies to 100 mg11 and greater influent TSS. Below 100 mg1L influent TSS, the goal is 20 mg1L effluent TSS. Technology Description: The Stormwater Management StormFilter® (StormFilter), a flow -through stormwater filtration system, improves the quality of stormwater runoff from the urban environment by removing pollutants. The Ston- Filter can treat runoff from a wide variety of sites including, but not limited to: retail and commercial development, residential streets, urban roadways, freeways, and industrial sites such as shipyards, foundries, etc. Operation: The StormFilter is typically comprised of a vault that houses rechargeable, media -filled, filter cartridges. Various media may be used, but this designation covers only the zeolite- perlite-granulated activated carbon (ZPGTM) medium. Stormwater from storm drains percolates through these media -filled cartridges, which trap particulates and may remove pollutants such as dissolved metals, nutrients, and hydrocarbons. During the filtering process, the StormFilter system also removes surface scum and floating oil and grease. Once filtered through the media, the treated stormwater is directed to a collection pipe or discharged to an open channel drainage way. This document includes a bypass schematic for flow rates exceeding the water quality design flow rate on page 8. CONTECH - StormFilter® GULD Maintenance Update (November 2012) Page 17 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT StormFilter Configurations: Contech offers the StormFilter in multiple configurations: precast, high flow, catch basin, curb inlet, linear, volume, corrugated metal pipe, drywell, and CON/Span form. Most configurations use pre -manufactured units to ease the design and installation process. Systems may be either uncovered or covered underground units. The typical precast StormFilter unit is composed of three sections: the energy dissipater, the filtration bay, and the outlet sump. As Stormwater enters the inlet of the StormFilter vault through the inlet pipe, piping directs stormwater through the energy dissipater into the filtration bay where treatment will take place. Once in the filtration bay, the stormwater ponds and percolates horizontally through the media contained in the StormFilter cartridges. After passing through the media, the treated water in each cartridge collects in the cartridge's center tube from where piping directs it into the outlet sump by a High Flow Conduit under -drain manifold. The treated water in the outlet sump discharges through the single outlet pipe to a collection pipe or to an open channel drainage way. In some applications where you anticipate heavy grit loads, pretreatment by settling may be necessary. CONTECH - StormFilter® GULD Maintenance Update (November 2012) Page 18 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT 5TC)RMGATE ANNOLE, 11GI FLOW BYPASS EFFECTIVE CARTRIDGE 11EIGIIT 1 2" 1 18" 2T CARTRIDGE FLOW RATE {9PWc rt) 5 7.5 1 1 .3 02DDS COHTECH DGE OW} A.4LkrjVW0hU, STORMFILTER WITH STORMGATIE nRnwiM I~M i =f� SCHEMATIC DETAIL STORMWAiER 50LlJTIONS.4A_ PLAN VIEW ,1, 1 GATE:11i1195 SCALE:NCNE FILE NAME: Sr MH-8F5lr QTI9-SGH OWWN:MPN CHECKED:. Figure 1. Stormwater Management StormFilter Configuration with Bypass CONTECH - StormFilter® GULD Maintenance Update (November 2012) Page 19 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT AIR LOCK CAP WITH CHECK VALVE � _,LIFTING TAB FLOA7 VALVE LAOUTER MESH FILTER MEDIA HOOD CENTER TUHL SCRUBBING REGULATOR UNFILTERED WATER UNDER -DRAIN MANIFOLD FILTERED WATER UNDER -DRAIN VANIFOLD CAST INTO VAULT FLOOR Figure 2. The StormFilter Cartridge Cartridge Operation: WATER FILTERED WATER VAULT FLOOR As the water level in the filtration bay begins to rise, stormwater enters the StormFilter cartridge. Stormwater in the cartridge percolates horizontally through the filter media and passes into the cartridge's center tube, where the float in the cartridge is in a closed (downward) position. As the water level in the filtration bay continues to rise, more water passes through the filter media and into the cartridge's center tube. Water displaces the air in the cartridge and it purges from beneath the filter hood through the one-way check valve located in the cap. Once water fills the center tube there is enough buoyant force on the float to open the float valve and allow the treated water to flow into the under -drain manifold. As the treated water drains, it tries to pull in air behind it. This causes the check valve to close, initiating a siphon that draws polluted water throughout the full surface area and volume of the filter. Thus, water filters through the entire filter cartridge throughout the duration of the storm, regardless of the water surface elevation in the filtration bay. This continues until the water surface elevation drops to the elevation of the scrubbing regulators. At this point, the siphon begins to break and air quickly flows beneath the hood through the scrubbing regulators, causing energetic bubbling between the inner surface of the hood and the outer surface of the filter. This bubbling agitates and cleans the surface of the filter, releasing accumulated sediments on the surface, flushing them from beneath the hood, and allowing them to settle to the vault floor. Adjustable cartridge flow rate: Inherent to the design of the StormFilter is the ability to control the individual cartridge flow rate with an orifice -control disc placed at the base of the cartridge. Depending on the treatment requirements and on the pollutant characteristics of the influent stream as CONTECH - StormFilter® GULD Maintenance Update (November 2012) Page 110 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT specified in the CONTECH Product Design Manual, operators may adjust the flow rate through the filter cartridges. By decreasing the flow rate through the filter cartridges, the influent contact time with the media is increased and the water velocity through the system is decreased, thus increasing both the level of treatment and the solids removal efficiencies of the filters, respectively (de Ridder, 2002). Recommended research and development: Ecology encourages CONTECH to pursue continuous improvements to the StormFilter. To that end, CONTECH recommends the following actions: • Determine, through laboratory testing, the relationship between accumulated solids and flow rate through the cartridge containing the ZPGTM media. Completed 11/05. • Determine the system's capabilities to meet Ecology's enhanced, phosphorus, and oil treatment goals. • Develop easy -to -implement methods of determining that a StormFilter facility requires maintenance (cleaning and filter replacement). Contact Information: Applicant Contact: Jeremiah Lehman Contech Engineered Solutions 11835 NE Glenn Widing Drive Portland, OR, 97220 503-258-3136 j lehman(c�r�,conteches. com Applicant Web link http://www.conteches.com/ CONTECH - StormFilter® GULD Maintenance Update (November 2012) Page 111 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT Ecology web link: http://www.ecy.wa. _og_y/pro,grams/wq/stonnwater/newtech/index.html Ecology Contact: Douglas C. Howie, P.E. Department of Ecology Water Quality Program (360) 407-6444 douglas.howie@ecy.wa.gov Revision History Date Revision Jan 2005 Original Use Level Designation Dec 2007 Revision May 2012 Maintenance requirements updated November 2012 Design Storm and Maintenance requirements updated January 2013 Updated format to match Ecology standard format September 2014 Added Peak Diversion StormFilter Alternate Configuration November 2016 Revised Contech contact information April 2017 Revised sizing language to note sizing based on Off-line calculations CONTECH - StormFilter® GULD Maintenance Update (November 2012) Page 112 APPENDIX B-STORMWATER POLLUTION PREVENTION PLAN This Stormwater Pollution Prevention Plan (SWPPP) has been prepared as part of the Construction stormwater permit requirements for the Kisan Enterprises located at 22810 Edmonds Way, Edmonds, Washington. More generally, the site is located in Section 36, Township 27 North, and Range 3 East of the Willamette Meridian in Snohomish County, Washington. The site was developed with a home and an asphalt driveway from Edmonds Way. The home has been demolished already. The site contains one drainage basin that drains to the northern portion of the lot. Please refer to the downstream analysis map attached under Stormwater Site Plan dated July 29, 2020 for more details. Per NRCS survey of Snohomish County, the majority of the project site contains Everett soils that have a hydrologic classification of Type "A", The rest of the site contains Pits soil and Alderwood soil which has a hydrologic classification of Type "C". Please refer to the soils map and descriptions attached under Stormwater Site Plan dated July 29, 2020 for more details. A Geotechnical Engineering Study was performed by Earth Solutions NW, LLC. Please refer to the report attached under the Section 6 Appendix E in Stormwater Site Plan dated July 29, 2020 for more details. The project area has been divided into Subbasin-1 and Subbasin-2. Subbasin-1 includes Building-C, onsite access drive. These areas will be connected to the proposed detention pipe. The detention pipe (130 LF X 9') with a dead storage of V and detention volume of 7,840 CF will be located under the access drive. The developed site drainage will be discharged to the existing drainage system on Edmonds Way to continue its natural drainage flow path. Water quality will be met by 1-27" single cartridge steel catch basin stormfilter manufactured by Contech Engineered Solutions LLC located upstream of detention. Subbasin-2 includes Building -A, Building-B, Building-D and Frontage access road and sidewalk. The runoff from these areas will be directed existing drainage system on Edmonds Way to continue its natural drainage flow path. Per ECDC 18.30.060.D.5.d Minimum Requirement #5: On -site Stormwater Management, the following roof BMPs must be considered in the following order: Full Dispersion or Full Infiltration, Bioretention, Downspout Dispersion Systems, Perforated Stub -out Connections, and Detention Vaults or Pipes. The roof drain from Building- C will be directed to the detention pipe. Please refer to Appendix A in Stormwater Site Plan dated July 29, 2020 for tables detailing BMP Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -36- feasibility. Per ECDC 18.30.060.D.5.d Minimum Requirement #5: On -site Stormwater Management, the BMP's for other hard surfaces must be considered in the following order: Full Dispersion, Permeable Pavement, Bioretention Sheet Flow Dispersion, Detention Vault or Pipe. The runoff from the access drive and driveways will be directed to the detention Pipe through a Contech stormfilter. Please refer to Section 6 Appendix A in Stormwater Site Plan dated July 29, 2020 for tables detailing BMP feasibility. Post -Construction Soil Quality and Depth BMP T.5.13 is proposed to provide onsite stormwater management for the pervious areas of the site. The purpose of this SWPPP is to describe the proposed construction activities and all temporary and permanent erosion and sediment control (TESC) measures, pollution prevention measures, inspection/monitoring activities, and recordkeeping that will be implemented during the proposed construction project. The objectives of the SWPPP are to: 1. Implement Best Management Practices (BMPs) to prevent erosion and sedimentation, and to identify, reduce, eliminate or prevent stormwater contamination and water pollution from construction activity. 2. Prevent violations of surface water quality, ground water quality, or sediment management standards. 3. Prevent, during the construction phase, adverse water quality impacts including impacts on beneficial uses of the receiving water by controlling peak flow rates and volumes of stormwater runoff at the Permittee's outfalls and downstream of the outfalls. This SWPPP was prepared using the Ecology SWPPP Template. This SWPPP was prepared based on the requirements set forth in the Construction Stormwater General Permit and in the Stormwater Management Manual for Western Washington (SWMMWW 2005). Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -37- The 13 BMP Elements Element #1— Mark Clearing Limits To protect adjacent properties and to reduce the area of soil exposed to construction, the limits of construction will be clearly marked before land -disturbing activities begin. Element #2 — Establish Construction Access Construction access or activities occurring on unpaved areas shall be minimized, yet where necessary, access points shall be stabilized to minimize the tracking of sediment onto public roads, and wheel washing, street sweeping, and street cleaning shall be employed to prevent sediment from entering state waters. Install the temporary construction entrance, according to the approved construction plans, prior to any clearing or grading activities. Maintain until the access road is paved. Element #3 — Control Flow Rates In order to protect the properties and waterways downstream of the project site, stormwater discharges from the site will be controlled. In general, discharge rates of stormwater from the site will be controlled where increases in impervious area or soil compaction during construction could lead to downstream erosion, or where necessary to meet local agency stormwater discharge requirements. Element #4 — Install Sediment Controls Install silt fencing, according to the approved plans, prior to any clearing or grading activities. Maintain until all construction activities are completed. Install storm drain inlet protection, according to the approved construction plans, as catch basins become operable. Maintain until all construction activities are completed. Element #5 — Stabilize Soils Exposed and un-worked soils shall be stabilized with the application of effective BMPs to prevent erosion throughout the life of the project. Apply temporary hydro -seed to exposed and un-worked soils, according to the approved construction plans, as needed to prevent erosion during site grading. Apply permanent hydro -seed to areas at final grade as site grading is completed. Apply mulching to exposed and un-worked soils, according to the approved construction plans, as needed to prevent erosion during site grading. Maintain until site grading is completed and permanent hydro -seed is applied. Cover stockpiles with plastic sheeting, according to the approved construction plans, as needed to prevent erosion during site grading. Maintain until stockpiles are removed from site. Element #6 — Protect Slopes All cut and fill slopes will be designed, constructed, and protected in a manner than minimizes erosion. The following specific BMPs will be used to protect slopes for this project. Element #7 — Protect Drain Inlets All storm drain inlets and culverts made operable during construction shall be protected to prevent unfiltered or untreated water from entering the drainage conveyance system. However, the priority Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -38- is to keep all access roads clean of sediment and keep street wash water separate from entering storm drains until treatment can be provided. Element #8 — Stabilize Channels and Outlets Where site runoff is to be conveyed in channels or discharged to a stream or some other natural drainage point, efforts will be taken to prevent downstream erosion. Element #9 — Control Pollutants All pollutants, including waste materials and demolition debris, that occur onsite shall be handled and disposed of in a manner that does not cause contamination of stormwater. Good housekeeping and preventative measures will be taken to ensure that the site will be kept clean, well organized, and free of debris. Element #10 — Control Dewatering There will be no dewatering expected as part of this proposal. If it occurs, Baker tanks will be used for dewatering. Element #11— Maintain BMPs All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP's specifications. Visual monitoring of the BMPs will be conducted at least once every calendar week and within 24 hours of any rainfall event that causes a discharge from the site. If the site becomes inactive, and is temporarily stabilized, the inspection frequency will be reduced to once every month. All temporary erosion and sediment control BMPs shall be removed within 30 days after the final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil resulting from removal of BMPs or vegetation shall be permanently stabilized. Element #12 — Manage the Project Erosion and sediment control BMPs for this project have been designed based on the following principles: Design the project to fit the existing topography, soils, and drainage patterns; Emphasize erosion control rather than sediment control; Minimize the extent and duration of the area exposed; Keep runoff velocities low; Retain sediment on site; Thoroughly monitor site and maintain all ESC measures and Schedule major earthwork during the dry season. The SWPPP shall be modified as necessary to include additional or modified BMPs designed to correct problems identified. Revisions to the SWPPP shall be completed within seven (7) days following the inspection. Element #13 - Protect Onsite Stormwater Management BMPS for Runoff from Roofs and other Hard surfaces NA Insight Engineering Co. - Stormwater Site Plan 5/20/21 REVISION May 20 2021 DEVELOPRVICES DEPARTMENT -39- REVISION BLD2020-0017- May 202021 R E S U B 1 of DEPARTMENT Es Bouyancy and Pipe Cover Calculations Pipe Diameter (D) = 9 feet Pipe Weight* (W) = 115 lb/ft3 Density of Soil (ps)= 120 lb/ft' Density of Water (pw) = 62.4 lb/ft' Pipe Area (AP) = 2 63.6 ft Bouyancy Force: Fup= pW*Ar-W Fup- 3854.7 I b/ft Required Fill: Area Required to balance Fup (a) = Fup PS a = 32.1 ft2 Solve for Depth (d): a=A,+A2 Therefore: a—A2 d= D d = 2.60 feet A, = d*D A 1 D2-17C(D)2 2 2 8 A2 = 8.7 ft2 Therefore use 2.6 feet of minimum cover * Pipe weight assumes 16 gauge (0.064 inches) steel with Aluminized coating Pipe information taken from the Washington Culvert Design Catalog pg 58b. 'w6- �+ v�v v�' Reviewer confirmed that proposed plans met this minimum cover requirement; no review of methodology or calculations performed and no approval of accuracy is - warranted. Responsibility for adequacy of buoyancy control remains with design - engineer, as was stated in previous email communications. -ZR 7/15/2021