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HomeMy WebLinkAboutSWP272327 SURFACE WATER DRAINAGE ANALYSIS FOR THE GURUDWARA SINGH SABA OF WASHINGTON Renton, Washington December 2, 1996 IFtgo? of DEC 3 - 1996 801-014G tpio 4 - S CJ F WAS Nc�iG aP O STE¢E� ONAL EXPIRES:3/1 2/97 Job No. : 96-046 SEGA Engineers/ Structural & Civil Consulting Engineers 22928 SE 312"ST (360)886-1017 Kent,WA 98042 Cupyri&t 1996,SEGA Engk� 1 SURFACE WATER DRAINAGE ANALYSIS FOR THE GURUDWARA SINGH SABA OF WASHINGTN SECTION 31, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M. RENTON, WASHINGTON December 2, 1996 Introduction This portion of the analysis is included to give a brief overview of the project and a description of the existing storm drainage system on and off the site. For this analysis two site visit(s) were made to note the condition of the existing drainage system. Field observations were completed on April 8, 1996. The proposed project involves the construction of a new temple building, parking facilities, and associated improvements. The project also involves demolition of a two existing buildings. Existing site topographic maps, U.S.G.S. maps, City of Renton Storm Drainage maps, and a field investigation were used to determine the existing drainage configuration. Proposed Site The proposed Sikh Temple is located on Talbot Road approximately 1/4 mile north of the intersection of S 55th Street and Talbot Road, in Renton, Washington. The site is approximately 4 acres and is currently developed with two existing temple buildings, a private residence, landscaping, a paved parking lot and a grass area used for parking. The new temple building will be located at the west central portion of the site. An existing residence on the north side of the site and the eastern most temple building will be demolished and removed. Approximately 64,000 sf of new paved parking lots will be constructed on the north, south and west side of the new Temple building. The existing church parking lot(approximately 20,000 so will be re-graded to match new grades. Existing Drainage Conditions Surface runoff from the existing site is conveyed to a storm drain system located on the temple grounds. Surface runoff from the parking lot is collected in catch basins and conveyed to the existing 12-inch storm sewer at the southwest comer of the existing parking lot. Flows are then conveyed into an underground detention system located at the southwest comer of the site. Runoff from the detention pipe is conveyed into a swale that flows southerly along Talbot Road. Approximately 120 feet south of the site, runoff enters a culvert that crosses Talbot Road from east to west and discharges into a wetland area. • Gurudwara Singh Saba Church. Storm Water Drainage Analysis. Two well defined drainage channels convey storm water off-site from the area to the east of the site. The southern most channel conveys storm water from uphill areas and a well house that is located at the south east comer of the site. Flows in this channel are conveyed into an 8-inch ductile iron pipe that connects to the existing storm water collection system on the site. The northern swale conveys flows from the uphill areas to the east of the site. The tributary area for both of these swales is approximately 7.35 acres. This area is wooded and slopes to the west at about 7%. An existing wetland is located at the southeast end of the site. This wetland has been delineated by wetland consultants and is approximately 0.28 acres. The wetland is located on a hillside with slopes to 7%. A portion of the wetland (approximately 0.10 acres) will be removed as a result of this project. To mitigate this a new wetland area (approximately 0.12 acres) will be constructed on the east side of the site. Method of Analysis Drainage calculations were performed using methods described in Chapter 3 -- Hydrologic Analysis, of the King County Surface Water Drainage Manual. Peak runoff rates for the pre- developed and post developed conditions were calculated using the Santa Barbara Urban Hydrograph Method. The Water Works design program by Engenious Systems was used to develop peak runoff rates for the various hydrographs. King County Drainage Manual— Core Requirements Core Requirement # 1. Discharge at the Natural Location: Runoff in the area of the proposed building addition currently discharges into a series of ditches and storm drain pipes that convey flows southerly along the east side of Talbot Road. Approximately 120 feet south of the site, runoff enters an 18-inch storm drain pipe that crosses Talbot Road from east to west and discharges into a wetland area. The proposed development will in no way divert or change the location of the existing surface water discharge point. Runoff from the proposed development will be tight-lined into the existing on-site conveyance system and will be routed into a new two cell combination detention/wet pond. Storm water will be conveyed from this facility into a new storm drain system that will be constructed along the east side of Talbot Road. Runoff will be discharged into an existing ditch just south of the site. These flows will continue to drain south in the existing ditch to the storm drain pipe that crosses Talbot Road. The existing drainage swale that carries flows from the area to the east of the site will be routed into the new conveyance system in Talbot Road and conveyed into the ditch to the west of the site. The combination detention/wet pond facility will be designed to discharge peak flows from the developed site from the 2-vr., 10-yr. and 100-yr. 24-hr. storms at the pre-developed flow rates (refer to Core Requirement#3). Runoff from the entire area of development will be routed into 2 Gurudwara Singh Saba Church. Storm Water Drainage Analysis. the detention facility. Runoff from the areas to the east of the development will be diverted around the site and routed into the new off-site conveyance system along Talbot Road. There should no significant adverse impacts to the downstream properties. Core Requirement#2. Off Site Analysis: There is approximately 7.35 acres of upstream area tributary to the site. Runoff from this site currently discharges into two swales located on the site. Runoff from the entire site is currently conveyed in these swales to the series of ditches and culverts that are presently located along Talbot Road. From these ditches flows are conveyed to the storm drain pipe that crosses Talbot Road to the west and discharges into a wetland area on the west side of the roadway. The proposed conceptual drainage system will intercept the off-site flow and route it into the existing channel to the north of the development. The runoff will be conveyed westerly through the channel into the new storm drain system at Talbot Road. This storm drain system will convey flows to the existing ditch west of the site. Currently there is no evidence of any drainage problems that may exist in the project area, nor are any drainage problems predicted after development. The level I downstream analysis indicated that downstream conveyance system appeared adequate. At the time of our field investigation there was no evidence of flooding in the storm drainage system Core Requirement#3: Runoff Control: The existing site contains approximately 28,300 square feet(0.65 ac) of impervious area. After development, the new impervious area will be about 95,800 square feet(2.20 ac), resulting in a net increase of 67,500 square feet of impervious area. The proposed developed site will contain 60% impervious area and 40% pervious area. The drainage analysis indicates that the pre- developed condition peak flow for the 100-yr., 24-hr storm is 1.83 cfs, and the post-developed condition peak flow for the 100-yr., 24 hour storm is 2.52 cfs. Since the increase in the peak runoff for the 100-yr. storm event exceeds the 0.5 cfs threshold per King Countv SWDM, on- site storm water detention will be provided for this project. The detention pond will be constructed at the west end of the site near the entrance driveway. The maximum storage elevation will be 149.0 feet (100-yr., 24-hour storm event). Discharge from the detention system will be controlled by an outlet device with three orifices that will be sized for the controlled discharge rate requirements of the 2, 10 and 100 year storm events. The bottom orifice will be 5.58 inches the second orifice will be 5.13 inches and the third orifice will be 5.25 inches. The detention pond will provide 1.5 feet of live storage. The wetpond portion of the basin will have a minimum depth of 3.5 feet for water quality treatment. The proposed pond will provide an additional one foot of dead storage for sedimentation. A 10-foot emergency spillway will be constructed at elevation 149.5. The King County SWM requires a 30 percent safety factor for the detention pond volume. Detention for the site will be provided by a two cell detention pond that will provide 3 Gurudwara Singh Saba Church. Storm Water Drainage Analysis. approximately 4,175 cf of detention capacity. The required volume for the site is 3,113 cubic feet. The proposed pond will have a safety factor of 1.34. Computer generated hydrographs for the developed site were routed through the proposed detention pond and control manhole to determine the capacity of the proposed system. The results of the routing analysis indicate that the proposed system meets current requirements. See results of hydrograph routing analysis below: Table 1 H dro ra h Routing Storm Event Existing Peak Developed Peak Storage Peak Outflow Inflow Inflow Required (cf) cfs cfs c 2-yr. Storm 0.61 1.09 1,715 0.61 10- r. Storm 1.16 1.76 2,909 1.16 100-vr. Storm 1.26 1.84 3,113 1.23 As shown in the table above, the proposed pond and outlet control manhole with orifice riser will provide sufficient detention capacity. A 16 foot high (maximum) 'Keystone' retaining wall will be constructed along two of the sides of the detention pond. A guard rail will be placed along the top of the wall. The other two sides of the pond will be sloped at 3:1 maximum. The pond will be constructed in a driveway island and will be accessible from all sides. The maximum length from the driveway to the center of either cell is 30 feet. Since access for maintenance can be from the adjacent road, a standard maintenance access road into the pond will not be provided. Water Quality Control. Approximately 1.55 acres of new impervious vehicular parking and driving surface will be created as a result of this prnc+ -TheFefore,-watex quality treatment will be provided for the, -------- - new impervious surfaces (Physical-constraints on the site make cpnstruchon of a biofiltration wale very diffiSult ,(A mbined detention/wet pond will be provided for water quality con 6T.-"f'he--King County SWM requires that the area provided for water quality be at least 1 percent of the new impervious surface area and that the volume provided for water quality be 1/3 of the runoff volume for the 2-yr.-24 hour storm event for the new impervious surface area. Additionally, the City of Renton is requiring an additional 50 percent increase in the storage volume and the surface area. The required water quality treatment surface area is 1012.5 square feet and the water quality storage volume was determined to b 4,950 c bic feet. The wet pond will have approximately 5,666 cubic feet of water quality storage and will have a surface area of approximately 3,568 square feet. Core Requirement #4: Conveyance System: The proposed on-site conveyance system will consist of a roof collection system, parking lot catch basins, and an underground storm sewer system that will carry flows to the detention basin. 4 Gurudwara Singh Saba Church. Storm Water Drainage Analysis. The proposed conveyance system will be sized to carry flow from the 25 year storm event. Since the design drainage basin is less than 25 acres, and the time of concentration is less than 100 minutes, the capacity of the conveyance elements will be determined using the Modified Rational Method as described in SW DM Section 4.3.3. The existing channel on the north side of the site was sized to determine the required cross section for carrying flows from the uphill areas. The results of the sizing show that a 1.5 foot deep channel with 3:1 side slopes will have sufficient capacity to carry flows for the 25-yr storm, and will not crest during the 100-yr. storm event. Core Requirement #5:Erosion & Sedimentation Control Plan: A temporary erosion and sediment control plan has been prepared for the site to reduce the risk of erosion or sediment laden runoff leaving the site. We recommend the following measures be taken: • A silt fence should located along the west side of the new parking along the frontage with Talbot Road. The fence should be extended approximately 120 feet east along either side of the development area. • Temporary drainage interceptor ditches with rock check dams placed at 50 foot intervals should be constructed to convey runoff from the uphill areas of the site into a temporary sedimentation pond to be installed in the location of the proposed detention/wet pond facility. • Existing catch basins will be fitted with filter fabric to prevent sediment from entering the storm drain system. • New catch basins will be fitted with a filter BMP as pavement is installed. • A permanent wetpond / detention pond will be constructed during the clearing period of construction and used as a temporary sediment pond for the duration of construction. After all construction is complete and the site is stabilized, the sediment pond and the storm drainage system will be cleaned and the sediment pond will be converted to the wetpond / detention pond. We do not anticipate any adverse impact to the down stream features due to the oversized sediment pond. A cross section of the sediment, including all necessary dimensions, is shown on the plans. The sediment pond storage volume was computed per King County SWDM section 5.4.4.2. The required sediment storage volume was computed to be 480 cf. The supplied sediment storage volume is 5,666 cf and allows for a factor of safety of 11.8. The required surface area was calculated to be 2,200 sf. The supplied surface area for the sediment pond is 3,568 sf and allows for a 1.6 factor of safety. • The temporary sedimentation pond should be equipped with a cone riser and gravel filter and will be connected to the new storm drainage conveyance system. • The site should be monitored and additional BMP's implemented, if necessary, as construction continues. • The project construction drawings shall include the City of Renton Standard Construction and Erosion Control Notes. These notes address the additional T.E.S.C. BMP's that may be necessarv. 5 Gurudwara Singh Saba Church. Storm Water Drainage Analysis. Core Requirement#6:Maintenance and Operation: A maintenance and operation requirement for private facilities will be provided per the King County SWM. Core Requirement#7. Bonds and Liability: Bonding will be provided per the King County SWM. Special Requirement#5: Special Water Quality Controls: The proposed drainage system will drain into an existing wetland area. Special water quality controls will be provided for the project. The combined detention/wet pond will be sized to meet the King County SWM requirements for special water quality controls. See Core Requirement #3: Runoff Control: above. Summary Our investigation indicated that there is no record of any drainage problem within the 1/4 mile downstream conveyance system. The proposed development will not divert runoff from the natural existing location. A detention/wet pond facility will be constructed to control release rates from the site for the 2, 10, and, 100 year storm events. The proposed expansion is in compliance with the City of Renton drainage codes and the King County Surface Water Design Manual. There is no evidence of any drainage problems that may exist in the project area, nor are any drainage problems predicted after development. The Level I downstream analysis indicates the conveyance system appears adequate and there was no evidence of any bank sloughing or erosion. b 1lST SE 1&I1N N t A pi I I wI '-ll day ' SF- IBIxO '< Si N . 4!I it y .. 1 cx IFTIp � 32 -- 9 s WIN"' ST a w Tx N 0 —- Y SE >l BFTX ST 5[ Mug 5 leln,�a I 5 1BrtX T 1 5 S7T 6 Jll .a _' sE BX x � T a �-(•4��>• - ry S SSTH � 6T I� SE - �c192e` ST u � Y ISM I� - � E • ��' .. 196M S 110. 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Ur�4• .�r 1 U Ago Pu sm AkF Project Number: E `� Project Name: S tc N BMos Month: 4,,-A?it- Year /996 Sr • 3s "° Agc ZP<VEL I ng,3 Page: of Os ;I ABC I Map Name: SnrLS MAP l _-- «l r� -- FI. �i �' Re 1 1II I . ... •_ti�9:h`"� //�1� " ,.T' �F �1�f �Irl ✓.L� I',711�1,�J:�. 11'--.1 �„gl•I. ,^., _ Hydrob aph ?riput Worksheet Project: Draage Basin Identification (5 char): '1 r (� - I r re, in Description(30 char): r Total Area: Precipitation: (500/-)2yr_ zyr L0 537 ioy7r z •9 25yr 50yr Iooyr 3.9 Hydrograph Numbers: (50%)2yr_ zyr Syr ioyr 25yr 50yr 10oyr Time of Concentration: length slope surface type "ri'value time u,S 100 / Gera < G .6 ��ss / G Gee/ — ;i Total Travel Time: 1 �• Pervious Area: 3.o 3 Impervious Area: Curve Number. (pervious) (impervious) J Land Use Grass l�nr � h 9-r� �aveCJ �caG's � ry55 �rgcL f � Soil Type AI /2ru cnrl SGY LS Hydrologic Soil Group: C CPL Job No. �6 0066 6! I Date• �� l7 Cl� �j 217 PIKE SiREE7 SURE 520 SEAME.WA 96101 -P:206l343-0160 F:M6r� 5691 Hydrob aph Input Worksheet Project S I P o,7 Drainage Basin Identification(5 char): / -�/� / /� aP- �/ /y O a r 02✓ Description(30 char): GJ e /v �eU S �e• F Total Area: 3 R Precipitation: (50%)2yr_ 2yr �Z, O 5}� l0yr •�l 25yr 50yr 100yr Hydrograph Numbers: (50%)2yrJ 2yr Syr 10yr 25yr 50yr 100yr Time of Concentration: length slope surface type "ri' value time 6 d 5 = C/oser� &46, 4 O.O/ /0 �V,n Total Travel Time: /0 m Pervious Area: / y AG Impervious Area: 2. 2 0" c- Curve Number. (pervious) 8'6 (impervious) /9 Land Use: /1 lrl / sl /�G v �v 1 Una La �1 s � OL 0 1»a 1 , � 1 Soil Type: dLJXr , Hydrologic Soil Group: C CPL job No. y O Date: a /7 �76 1 .17 PONES:REET,SUgE= SEAME.WA 9E1G: is bu<?-0460 F�D6/S<35691 KING COUNTY, W AS HINGTON. SURFACE WATER DESIGN MANUAL FIGURE 3.5.1C 2-YEAR 24-HOUR ISOPLUVIALS e 1. '' f — � � RNIl1 � p �✓ W % t :' \ •i y's p �x ry ti \ 2-YEAR 24-HOUR PRECIPITATION �3.4^ ISOPLUVIALS OF 2-YEAR 24-HOUR TOTAL PRECIPITATION N INCHES ry = 0 1 2 3 4 5 6 7 8 Mlles /5� -- 1: 300.000 KING COUNTY, W AS HINGTON, SURFACE WATER DESIGN MANUAL FIGURE 3.5.1E 10•YEAR 24-HOUR ISOPLUVIALS — 22 23 I 24 ' 4 2 - 27 2.8 I ' � ° � ,� � •�Y 3.0 33 41 c 4L n� _ i1 i . i d ��1 I 10-YEAR 24-HOUR PRECIPITATION 3.4-` ISOPLUVIALS OF 10-YEAR 24-HOUR TOTAL PRECIPITATION IN INCHES O ,� 0 1 2 3 4 5 6 ] 6 Mlles 1: 300,000 3.5.1-10 1/90 KING COUNTY, W ASHINGTON, SURFACE WATER DESIGN MANUAL FIGURE 3.5.11H 100-YEAR 24-HOUR ISOPLUVIALS 3 -- ----- _ - --- - - - -- - - lL 1 •� � y 41 •i ' -- "`� 1,� ��a"� ' - � � Q= i — I aJ 46 I - o ar d I a O tv � 4'b 140-YEAR 24-HOUR PRECIPITATION a� ✓ 6.� i 3.4—ISOPLUVIALS OF 100-YEAR 24-HOUR Q�• y Jr.$ TOTAL PRECIPITATION IN INCHES 0 1 2 3 4 5 6 7 8 Mlles O C•.".` + 3.5.1-13 �. 1 11/15/96 2 :48 : 2 pm page 1 Sikh Temple Drainage Analysis -----_____ __________________ - BASIN SUMMARY {SA firs BASIN ID: 100 r-dv NAME: 10 DEV LOPED SITE SBUH METHODOLOGY _ TOTAL AREA. . . . . . . . (2 40 Acres ABASE LOWS : 0 . 00 cfs , RAINFALL TYPE . . . . . �YzlA PERV IMP PRECIPITATION. . . . : 3 . 90 inches AR A. . : 0 . 20 Acres 2 . 20 Acres TIME INTERVAL. . . . : 10 . 00 min C . . . . : 86 . 00 98 . 00 T . . . . . 10 . 00 min 10 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 300 . 00 ns : 0 . 150 p2yr: 2 . 00 s : 0 . 0660 TcReach - Shallow L : 280 . 00 ks : 11 . 0 s : 0 . 0660 PEAK RATE: 1 . 84 cfs VOL: 0 . 71 c-ft TIME: 480 min BASIN ID: 100 r- r NAME : 1 -YR PRE DEVELOPED SITE SBUH METHODOLOGY TOTAL AREA. . . . . . . : 2 . 40 Ac BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : --TY15-E-lA PERV IMP PRECIPITATION. . . . : 3 . 90 inches AREA. . : 1 . 75 Acres 0 . 65 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 17 . 91 min 17 . 91 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 300 . 00 ns : 0 . 1300 p2yr: 2 . 00 s : 0 . 0660 TcReach - Shallow L: 280 . 00 ks : 13 . 00 s : 0 . 0660 PEAK RATE: 1 .26 cfs VOL: 0 . 54 Ac-ft TIME : 480 min BASIN ID: 10 r-dev NAME: 10-YR DEVELOPED SITE SBUH METHODOLOGY TOTAL AREA. . . . . . . : 3 . 68 Ac BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : lA PERV IMP PRECIPITATION. . . . : 2 . 90 inches AREA. . : 1 .48 Acres 2 . 20 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . : 10 . 00 min 10 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr : 2 . 00 s : 0 . 0660 TcReach - Shallow L: 280 . 00 k5 : 11 . 00 s : 0 . 0660 PEAK RATE: 1 . 76 cfs VOL: 0 . 68 Ac-ft TIME : 480 min 11/15/96 2 :48 : 2 pm page 2 Sikh Temple Drainage Analysis BASIN SUMMARY BASIN ID: 10 r- re N 10-YR PRE DEVELOPED SITE SBUH METHODOLOGY TOTAL AREA. . . . . . . : 3 . 68 cres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : ElA PERV IMP PRECIPITATION. . . . : 2 . 90 inches AREA. . : 3 . 03 Acres 0 . 65 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 17 . 91 min 17 . 91 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0660 TcReach - Shallow L: 280 . 00 ks : 11 . 00 s : 0 . 0660 PEAK RATE : 1 . 16 cfs VOL: 0 . 52 Ac-ft TIME: 480 min BASIN ID : 2 r-dev NAME: DEVELOPED SITE SBUH METHODOLOGY ' TOTAL AREA. . . . . . . : 3 . 68 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : - -TYPElA PERV IMP PRECIPITATION. . . . : 2 . 00 inches AREA. . : 1 . 48 Acres 2 . 20 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . : 10 . 00 min 10 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0660 TcReach - Shallow L: 280 . 00 ks : 11 . 00 s : 0 . 0660 PEAK RATE: 1 . 09 cfs VOL: 0 .43 Ac-ft TIME : 480 min BASIN ID : 2yr-pre NAME• -YR PRE DEVELOPED SITE SBUH METHODOLOGY TOTAL AREA. . . . . . . : 3 . 68 Acre BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : PE PERV IMP PRECIPITATION. . . . : 2 . 00 inches AREA. . : 3 . 03 Acres 0 . 65 Acres TIME INTERVAL. . . . : 10 . O0 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 17 . 91 min 17 . 91 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0660 TcReach - Shallow L: 280 . 00 ks : 11 . 00 s : 0 . 0660 PEAK RATE: 0 . 61 cfs VOL: 0 . 30 Ac-ft TIME: 480 min 11/15/96 2 : 52 : 35 pm _�____ ___ _ . page 1 Sikh Temple Drainage Analysis --------------------------------------------------------------------- --------------- ----- ----- -------------- STAGE STORAGE TABLE CUSTOM STORAGE ID No. D-POND1 Description: DETENTION POND 1 STAGE <----STORAGE----> STAGE -----STORAGE----- STAGE -----STORAGE----> STAGE a----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- ­------------------------ Ana_ =----------=------------warm-----_--- ----_.-.---.----__---_--- 147.50 0.0000 0.0000 148.20 2338 0.0537 148.90 4676 0.1073 149.60 7896 0.1813 147.60 334.00 0.0077 148.30 2672 0.0613 149.00 Salo 0.1150 149.70 8377 0.1923 147.70 668.00 0.0153 148.40 3006 0.0690 149.10 5491 0.1261 149.80 8858 0.2034 147.80 1002 0.0230 148.50 3340 0.0767 149.20 5972 0.1371 149.90 9339 0.2144 147.90 1336 0.0307 148.60 3674 0.0843 149.30 6453 0.1481 150.00 9820 0.2254 148.00 1670 0.0383 148.70 4008 0.0920 149.40 6934 0.1592 148.10 2004 0,0460 148.80 4342 0.0997 149.50 7415 0.1702 11/13/96 8 : 5 : 10 am page 5 Sikh Temple Drainage Analysis - --------------------------------------------------------------------- --------------------------------------------------------------------- DISCHARGE STRUCTURE LIST COMBINATION DISCHARGE ID No. NEW-COMB Description: NEW COMBINATION ORIFIC/RISER Structure : NEW-ORIF Structure : Structure : NEW-RISK Structure : Structure : MULTIPLE ORIFICE ID No. NEW-ORIF Description: NEW MULTIPLE ORIFICE Outlet Elev: 147 . 50 Elev: 145 . 50 ft Orifice Diameter: 5 . 5840 in. Elev: 148 . 10 ft Orifice 2 Diameter: 5 . 1328 in. Elev: 148 . 50 ft Orifice 3 Diameter: 5 . 2500 in. RISER DISCHARGE ID No. NEW-RISR Description: NEW RISER Riser Diameter (in) : 12 . 00 elev: 149 . 00 ft Weir Coefficient . . . : 9 . 739 height : 150 . 00 ft Orif Coefficient . . . : 3 . 782 increm: 0 . 10 ft 11/13/96 8 : 5 : 11 am page 6 Sikh Temple Drainage Analysis --------------------------------------------------------------------- --------------------------------------------------------------------- LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- c-PEAR-> STORAGE a--------DESCRIPTION---------- (cfs) (cfs) --id- --id- a-STAGE, id VOL (cf) ff Gas »>.A'.�=_-'---------------------.-0.61-e--1e=ms»--,N-D=-,N..an.:a-ae1-4-8�s-1me-I-v-1- 2 YEAR STORM ............ ..... 0.61 1.09 D-POND1 NEW-COMB 148.01 1 1715.01 cf 0,61 10 YEAR STORM ................ 1.16 1.76 D-POND1 NEW-COMB 148.37 2 2909.53 cf 1, 5 100 YEAR STORM ............... 1.26 .84 -POND1 NEW-COMB 148.43 3 3112.65 c 1, 23 4�_ CSAc 4-C) SEGA Engineers PROJECT titrmtural & Civil Cunsuiting Engineers JOB NO. o�r.> FIGURED BY �N� _.12928 SF. 312th ST • Kent. Washington 0804'_ 1�t LL - (360) 886-1017 • Fax (360) 886-1016 CHECKED BY DATE piL SHEET OF 1,lETP�iVL7 G =�1 iV A EA aF NEi,, .I m ?r k1wov_ AR I,q C. 17-Y og' REN-104 �. CIS 0,r �. F F' FRFQ,3 f}R fA VOLUME ' I31'� OVE71z P, To7-A,I_ VoLu/i-! - 9, 9�? �• f. LPL ✓ < $ o �,'� ; z ;r �� '�N IZFQ40 VOL Ui le PR vv/DFQ 5� bo6 . .qr.u.ni i•eu. -i-G4 Ico;fCn 4/'17/96 10 : 9 : 16 am _ page 1 --------------------------------------------------------------------- BASIN SUMMARY BASIN ID: 2yr-wq NAME : 2-YR DEVELOPED SITE SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 55 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 . 00 Acres 1. 55 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 98 . 00 TC. . . . : 10 . 00 min 10 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Sheet L: 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0660 TcReach - Shallow L: 280 . 00 ks: 11 . 00 s : 0 . 0660 PEAR RATE: 0 . 61 cfs VOL: 0 .23 Ac-ft TIME: 480 min ) 0rA � F VbL.�Mr 'KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL -TABLE 3.5?11 SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS (Published by SCS in 1982) Runoff curve numbers for selected agricultural, suburban and urban land use for Type to rainfall distribution, 24-hour storm duration. CURVE NUMBERS BY HYDROLOGIC SOIL GROUP LAND USE DESCRIPTION A B C D Cultivated land(1): winter condition 86 91 94 95 Mountain open areas: low growing brush and grasslands 74 82 89 92 Meadow or pasture: I 65 78 85 89 Wood or forest land: undisturbed or older second growth 42 64 76 81 Wood or forest land: young second growth or brush 55 72 81 86 Orchard: with cover crop 8t 88 92 9a Open spaces, lawns, parks, golf courses, cemeteries, landscaping. good condition: grass cover on 75% or more of the area 68 80 9 90 fair condition: grass cover on 50% to 75% of the area 77 85 90 92 Gravel roads and parking lots 76 85 89 91 Dirt roads and parking lots 72 82 87 89 Impervious surfaces, pavement, roofs, etc. I 98 98 98 98 Open water bodies: lakes, wetlands, ponds, etc. 100 100 100 Single Family Residential (2) Dwelling Unit/Gross Acre % Impervious (3) 1.0 DU/GA 15 Separate curve number 1.5 DU/GA 20 shall be selected 2.0 DU/GA 25 for pervious and 2.5 DU/GA 30 impervious portion 3.0 DU/GA 34 of the site or basin 3.5 DU/GA 38 4.0 DU/GA 42 4.5 DU/GA 46 5.0 DU/GA 48 5.5 DU/GA 50 6.0 DU/GA 52 6.5 DU/GA 54 7.0 DU/GA 56 Planned.unit developments, % impervious condominiums, apartments, must be computed commercial business and industrial areas. (1) For a more detailed description of agricultural land use curve numbers refer to National Engineering Handbook, Section a, Hydrology, Chapter 9, August 1972. (2) Assumes roof and driveway runoff is directed into street/storm system. (3) The remaining pervious areas (lawn) are considered to be in good condition for these curve numbers. 3.5.2-3 11/92 SEGA En ineers PROJECT S►Hk ' Structural & Civil Consulting Engineers JOB NO. %-od b FIGURED BY SNP 22928 SE 312th ST + Kent, Washington 98042 11 (360) 886-1017 0 Fax (360) 886-1016 CHECKED BY DATEtl4Z/yy SHEET OF SEDIMF/vr Pow) /GCS/aN -- --- -- ( TRi3LE IS, V e/, R —tA _z--- = 3 g a oo SF (a. 9 T491 CSv. y, Q) i -- CV =_:( __ _ Copyn'hU9)6, SEGA E pmas - - SEGA Engineers PROJECT 51JO mmae Structural & Civil Consulting Engineers JOB NO. G,, _��1. FIGURED BY 22928 SE 312th ST • Ken[, Washington 98042 � - (360) 886-1017 • Fax (360) 886-1016 CHECKED BY - DATE r SHEET OF If—DiIj E-AIr POND pts/64) 1 Fg Ac ) 8 SCo' - s - Z 73 , q 8 i✓6tis Y II // f'�r9 ao5 y79, 6 —_ -Gipyrighl 1996. SEGA Enginccrs— - _. SEGA Engineers Sm'1I PROJECT ' Structural & Civil Consulting Engineers --JOB NO. ��� FIGURED BY 22928 SE 312th ST • Kent, Washington 98042 (360) 886-1017 • Fax (360) 886-L016 CHECKED BY DATE11/1VIt. SHEET OF -- SEDIMEtir Po/vp Des/6� CL�wr) - -rACrUZ 000 W FETE- = /,6 I --_.`it Copyright ISM, SECA Engineers.. _ — KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL o To complete the desian of the temporary sediment trap: I a. The 'Pond Geometry Equations" section in the "Reference portion at the back of the Manual may also be useful in designing the sediment trap. b. A 3:1 aspect ratio between the trap length and width of the trap is desirable. Length Is defined as the average distance from the inlet to the outlet of the trap. This ratio is included in the computations for Figure 5.4.4C for the surface area at the interface between the settling zone and sediment storage volume. C. Determine the bottom and top surface area of the sediment storage volume to be provided (see Figure 5.4.40) while not exceeding 1.5' in depth and 3:1 side slope from the bottom of the trap. Note the trap bottom should be level. d. Determine the total trap dimensions by adding an additional 2' of depth above the surface of the sediment storage volume, while not exceeding 3:1 side slopes, for the required settling volume. (see Figure 5.4.4C) TABLE SAAA HYDROLOGIC SOIL GROUP OF THE SOILS IN KING COUNTY SOIL SOIL EROD- EROD- HYDROLOGIC IBILITY HYDROLOGIC IBIUTY SOIL GROUP GROUP' FACTOR;W SOIL GROUP GROUP' FACTOR.W Alderwood C 0.15 Oroas Peat 0 0.00 rants,Aiderwoca C 0.15 Orkla 0 0.49 Arents, Everett B 0.17 Ovalf C 0.17 Beausite C 0.15 Pilchuck C 0.10 Bellingham 0 0.32 Puget D 0.28 Briscot 0 0.32 Puyallup B 0.28 Buckley 0 0.32 Ragnar B 0.32 Coastal Beaches Variable 0.05 Renton D 0.43 Eadmont Silt Loam 0 0.37 Rlverwash Variable Edgewick C 0.32 Saul C 0.37 Everett A 0.17' Sammamish 0 0.37 Indianola A 0.15 Seattle 0 0.00 Mtsap C 0.32 Shacar 0 0.00 Maus C 0.17 SI Silt C 0.37 Mixed Alluvial Land Variable 0.10 Snohomish 0 0.32 Nedton A 0.10 Sultan C 0.37 Newberg B 0.32 Tukwila 0 0.00 Nooksack C 0.37 Urban Variable Norm. Sandy Loam D 0.24 Woodinville D 0,37 HYDROLOGIC SOIL GROUP CLASSIFICATIONS A. (Low runoff potential). Soils having high lnNtratlon rates, even when thoroughly wetted,and consisting chiefly of deep,well-to-excessively drained sands or gravels. These soils have a high rate of water transmission. S. (Moderately low runoff potentiet). Soils having moderate Infiltration rates when thoroughly wetted, and consisting chiefly of moderately fine to moderately coarse textures. These soils have a moderate rate of water transmission. C. (Moderately high runoff potential). Soils having slow Infiltration rates when thoroughly wetted,and consisting chiefly of soils with a layer that Impedes dowrrward movement of water, or soils with moderately fine to fine textures. These sods have a stow rate of water transmission. D. (High runoff potential). Soils having very slow Infiltratlon rates when thoroughly wetted and consisting chiefly of Gay sods with a high swelling potential, sods with a permanent high water table, sods with a hardpan or Gay layer at or near the surface, and shallow sods over nearly Impervious material. These sods have a very slow rate of water transmission. From SCS,TR-55, Second Edition,June 1988, Exhibit A-1. Revisions made from SCS, Soils Interpretation Record, Form 05.September.1988. 5.4.4.1-3 1/90 m r � z slope IS Spines for following dope lengths 1,It(rnl IS voh(es for following elope lengths 1,(t(m) A 0 Aline gradlenl 10 20 31) 40 50 fill 70 till 90 IM 150 2M 2.50 :1M 50 4 450 500 600 700 800 900 1000 4A f� relio N. ", 49A1 (6.II 19.11 (IR.YI IIS.'L) 118.31 (21.3) (Y L4) (27.11 (:10.51 61fi1 IfiU 17fi1 (Oil (10 12 1 1371 (152) 1183) (213) (244) (274) (3051 0 41.5 0.06 0.07 0.07 WAS 0.08 0.09 0.09 0.09 0.09 0.10 0.10 11.11 0.11 0.12 0.12 0.13 0.13 0.13 0.14 0.14 0.14 0.15 0.15 C~ 100:1 1 O.Oli 0.181 11.10 11.10 0.11 11.11 0.12 0.12 0.12 0.0 0.14 0-14 0.15 O.16 0.16 O.Ifi 0.17 0.17 0.18 0.18 0.19 0.19 0.20 - z 2 0.10 11.12 0.11 11.IS 0.lfi 11.17 0.18 41.19 (1.19 0.211 0.23 0.25 0.211 0.28 0.29 0.30 0.32 0.33 0.34 0.36 0..17 0.39 0d0 r •-4 :1 11.11 0.111 0.20 0.22 0.23 0.25 0.26 0.27 0.28 0.29 0.32 0.35 0.38 0.40 OA2 0.43 0.45 0.46 0.40 0.51 0.54 0.55 0.57 4 11.16 0.21 0.25 0.28 0.30 0.33 O95 0.31 0.38 0.40 0.47 0.53 0.58 0.62 A.f.6 0.70 0.73 0.76 0.82 0.87 0.92 0.96 1.00 y IS•!I1;1 5 0.17 11.24 0.29 0.14 0.96 0.41 0.45 0.48 0.51 0.53 046 0.76 0.85 0.93 1.00 1.07 1.1:1 1.20 1.31 1.12 1.51 1.60 I.69 6 41.21 0.:111 0.17 0.43 0.48 0.52 0.66 0.60 O.G.1 0.67 0.82 095 1.06 1.16 1.26 1.34 1.43 1.50 1.65 1.78 1.90 2.02 2,13 'D 7 LL26 0.37 11.45 0.52 0.58 0.61 O.fi9 0.74 0.78 0.82 1.01 1.17 1.30 1.43 1.54 PAS 1.75 1.81 2.02 2.18 2.33 2.47 2.61 V' 123:1 8 0.31 (1,44 0.54 0.63 0.70 0.77 083 0.89 0.91 O.J'J 1.21 1.40 1.57 1.72 1.85 1.98 2.10 2.22 2.43 2.62 2.00 2.97 3.13 .T. 9 (1.37 0.',2 0.64 0.74 0.83 0.91 0.98 1.0.5 1.11 1.17 1.44 1.66 1.85 2.03 2.19 2.:15 2.49 2.62 2.87 3.10 3.32 3.52 3.71 z III:I I0 0.43 0.91 A.75 0.87 0.l17 1.116 I.IS 1.22 I.M 1.37 . 1.68 1.04 2.16 2.37 2.56 2.74 2.90 3.06 3.35 3.62 3.87 4.11 4.33 M 11 0.50 0.71 0.86 1.00 1.12 1.22 IA2 1.11 1.50 1.50 1.93 2.23 2.50 1.14 2' .16 3.35 3.53 3.67 4.18 4.47 4.74 4.99 � 8:1 0.61 0.86 1.05 1.22 1.36 1.49 1.61 1.72 1.82 1.92 2.15 2.7R .1004 3.13 .59 3.8 4.0 4.30 4.71 6.08 5.43 5.76 6.OS 1r 0.81 1.14 1.40 1.62 1.81 1.98 2.14 2.29 2.43 2.56 3.13 3.62 4.05 4.43 4.79 6.12 5.4 5.72 6.27 6.77 7.24 7.68 8.09 0 6:1 16.7 0.96 1.36 PAR 1.92 2.15 2.36 2.54 2.72 2.88 3.04 3.72 4.30 4.81 5.27 5.69 6.08 6.45 6.811 7.45 8.04 8.60 9.12 9.62 z 5:1 20 1.29 1.92 2.23 2.58 2.88 3.16 3.41 3.65 3.87 4.08 5.00 5.77 6.45 7.06 7.63 8.16 8.65 9.12 9.99 10.79 11.54 12.24 12.90 p 4%:1 22 1.51 2.13 2.61 3.02 3.37 3.69 8.99 4.27 4.53 4.77 5.84 6.75 7.54 8.26 8.92 9.54 10.12 10.67 11.68 12.62 13.49 14.31 15.08 C" A 4A 25 1.86 2.63 3.23 3.73 4.16 4M. 4.93 5.27 5.59 5.89 7.21 8.33 9.31 10.20 11.02 11.78 12.49 13.17 14.43 15.58 19.66 17.67 18.63 �7 30 2.51 3.56 4.36 5.0 5.62 6.16 6.65 7.11 7.64 7.95 9.74 11.25 12.67 13.77 14.88 1&91 16.87 17.78 19.48 21.04 22.49 23.86 25.15 IT]3:1 33.3 2.98 4.22 5.17 b.9f, 6.67 7.30 7.89 8.43 8.95 9.43 11.55 13.34 14.01 16.33 17.64 18.86 20.00 21.09 2.1.10 24.95 26.67 28.29 29.82 y 35 3.23 4.57 &GO 6.46 7.23 7.92 &M 9.14 9.70 10.22 12.52 1.1.46 16.16 17.70 19.12 20.44 21.68 22.86 25.04 27.04 28.91 30.67 32.32 f) 2:4:1 40 4.00 5.66 6.93 8.00 6.05 9.80 10.59 11,32 12.00 12.65 15.50 17.89 20.01 21.91 23.67 25.30 26.84 28.29 10.99 33.48 35.79 37.96 40.01 m 45 4.81 6.80 8.33 9.61 10.75 11.77 12.72 13.60 14.42 15.20 18.62 21.50 24.03 2G.33 28.44 30.40 32.24 33.99 37.23 40.22 42.99 45.60 48.07 2:1 50 5.64 7.97 9.76 11.27 12.60 13.81 14.91 15.91 16.91 17.82 21.83 25.21 28.18 10.87 33.34 35.65 37.81 39.85 43.66 47.16 50.41 63.47 56.36 55 6.48 9.16 11.22 12.96 14.48 15.87 17.14 18.32 19.43 20.46 25,09 28.97 32.39 35.48 38.32 40.97 43.45 45.80 50.18 64.20 57.94 61.45 64.78 Ig:1 57 6.62 9.64 11.80 13.63 15.24 16.69 18.03 19.28 20.45 21.55 2G.40 30.48 34.08 37.33 40.32 43.10 45.72 48.19 52.79 57.02 60.96 64.66 68.15 CIO 7.32 10.15 12.68 14.64 16.37 17.93 19.37 20.71 21.96 2.1.15 28.3S 32.74 36.60 40.10 43.31 46.30 49.11 $1.77 56.71 61.25 65.48 69.45 73.21 m MI 66.7 8.44 11.93 14.61 16.88 18.87 20.67 22.32 23.87 25,31 26.6111 32.68 37.74 42.19 46.22 49.92 53.37 56.60 50.66 65.36 70.GO 76.47 80.05 84.38 � 70 8.98 12.70 M55 17.96 20.08 2I99 2:1.75 25.39 26.93 28.39 34.77 40.15 44,89 49.17 53.11 56.78 60.23 63.48 69.54 75.12 80.30 05.17 89.78 75 9.78 13.81 16.94 19.56 21.87 2:1.95 25.87 27.66 29.34 30.92 37.87 43.13 48.89 53.56 57.85 61.84 65.60 69.15 75.75 81.82 87.46 92.77 97.79 m INA 80 IO.55 14.93 18.28 21.11 23AA 25.85 27.93 29.85 31.66 3:1.38 40.88 47.20 62.17 57.81 62.44 66.75 70.80 74.fi.7 81.76 88.31 04.41 100.13 105.55 N 85 11.30 15.98 19.bB 22.61 25.27 27.69 29.90 :II J7 33.91 :15.74 43.78 50.55 56.S1 61.91 66.87 71.48 75.82 79.92 87.55 94.57 101.09 107.23 113.03 90 12.412 MOO 20.82 24.04 26.88 29.41 31.00 34-00 Woo 38.01 46.55 63.76 M.10 65.84 71.11 76.02 80.63 84.99 93.11 100.57 107.51 114.03 120.20 � OS 12.71 17.97 22.01 25.41 28.41 31.12 33.62 35.91 38.12 40.18 40.21 56.82 63.53 69.59 75.17 80.36 85.23 89.84 98.42 106.30 113.64 120.54 127.06 z 1:1 lot) 11A 18.89 21.14 26.72 29.87 12.72 35.34 37.70 40.06 42.24 51.74 59.14 fr.79 73.17 19,03 84.49 89.61 94.46 101.48 111.77 119.48 126.73 133.59 4 •C.I.I.I.J(rum r65.41 x$e CIA x a 1` 1 z 4 `d 4 10.000{ r i 10.000 4 0Dfi51�7R.5) IS- le p,length. Feel.,(m z' l 1 dope.lee(h,fl(m X 0.3018) e slope e dependent m -exponent.3ford p..< %upon daps et.I to 3 D IO.R for open < I Y.,0.0 for.lope.1 W 3X, ' 0.4 for.lope.3.5 10 4.6X,.m1 �i 0.5(or e6q..e>6X I