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SWP272714
AMER rMUNEEMN W9 5.204 FLAE KrHT,Wd 980M . me 850.0gm . rah( 727-sm0 March 10 , 1997 ( � 2 D R A I N A G E C A L C U L A T I O N S RENTON CROWN APARTMENTS RAINIER AVE. SOUTH @ S . 118th ST. CITY OF RENTON PREPARED FOR: Grry of RPhtON Carlton Development Group, Inc . Mark Lundberg ApR 9 - 1997 Seattle, Wa . (206) 241-6241 DNIS100 BU1LO'NC PREPARED BY: James J. Jaeger, P .E . J. J�q r P. ?0734 �SfONALE ' EXPIRES 3VIj R i • I . PROJECT DESCRIPTION The proposed project is a multifamily residential development located west of Rainier Ave . S . between S . 118th St . and S . 120th St . , and west of the City of Renton Airport . It lies within the NW 1/4 of Section 7, Township 23 N. , Range 5 E. , W. M. The proposal includes 96 apartment units distributed within 7 buildings . A swimming pool and a recreational facility will also be part of the development . The project will gain access from Rainier Ave . S . , which is the only street that fronts the property. The proposed driveway will slope up to the west from Rainier Ave . at a maximum of 12%, with a gentler landing near the ROW line . The development will continue to rise up to the west with the driveways and parking aisles at a maximum grade of 8% . The existing site is an old gravel pit that has been idle for many years . Prior to that, a tavern was located at the site before being destroyed by fire . The south and west • perimeters are fairly steep treed slopes . These slopes are beyond the proposed development area and will not be disturbed. There is an existing office complex to the north. The project area includes a narrow, level bench adjacent to the street, wider to the north. A steep 15 ft . bank separates this lower bench from a much larger plateau in the central portion of the site . This is the primary area of the development . The site has had numerous geotechnical studies performed which have indicated the presence of significant fill areas . • Z II. CORE REQUIREMENTS AND WORKSHEET The drainage core requirements are identified in the City adaptation of the King County Drainage Manual . Each of these five core requirements have been reviewed and addressed in this report and accompanying drainage design. The core requirements -were addressed as follows : 1 . The natural drainage discharge location of the site is at the low corner which is the northeast corner along Rainier Ave . There are catch basins along Rainier Ave . that might collect the sheet flow down the site slopes . There are also catch basins along the south edge of pavement of the office complex parking area to the north which may also collect the existing runoff . The developed drainage will discharge into the existing 36" piped system that runs along the west and north edges of the project . This system was installed to collect runoff from the residential development west of the project . It also collects the runoff from the parking lot north of the subject site . The developed-discharge location will be near the northeast corner. 2 . An off-site drainage analysis is included in this report in Section VI . A level one off-site drainage analysis is included. 3 . Peak rate runoff control will be accomplished using a precast concrete detention vault and an orifice type flow restrictor. The project release rate will be equal to or less than the predeveloped peak flows for the 2 year and 10 year storms . The vault volume will also include a 309.- safety factor. 4 . A conveyance system will be designed and submitted with the engineering plans . A network of catch basins and pipes will generally be located along the centerlines of the driveways and parking lots . The pavement will have negative crowns to channel the runoff into the catch basins . The conveyance system will be able to handle the 25 year flows within the pipes and the 100 year flows within the catch basins or the driveway prisms . 5 . An erosion and sedimentation control plan will be submitted with the engineering plans . • 6 . Water quality enhancement will be accomplished with a wetvault . This volume will be located within the detention vault as 3 ft . of dead storage below the active detention volume within the vault . 3 Page 1 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET PROJECTPART I OWNER AND PART 2 PROJECT • • PROJECT ENGINEER AND DESCRIPTION Project Owner CO. O-Z-� -Q, 0 Project Name Cm ov1 Y earl S Address ?0 q- NE Location Phone 547 1(,an , 9�to Township 231�! Project Engineer e.s' yo.�aer , P. �_ Range Section 7 Company Qf — Project Size 7• S-1 AC Address Phone ± 03 So-� Upstream Drainage Basin Size /D AC PART 3 TYPE OF • 0 Subdivision 0 DOF/G HPA 0 Shoreline Management 0 Short Subdivision 0 COE 404 JS�rRockery 0 Grading 0 DOE Dam Safety 0 Structural Vaults Commercial 0 FEMA Floodplain 0 Other 0 Other 0 COE Wetlands HPA COMMUNITYPART 5 SITE - Community r Drainage Basin A— PARTO. 0 River _ _ 0 Floodplain (� Stream ._ 0 Wetlands —_ 0 Critical Stream Reach 0 Seeps/Springs 0 Depressions/Swales 0 High Groundwater Table �ake LJf- - 0 Groundwater Recharge Steep Slopes -MlDt Other 0 Lakeside/Erosion Hazard SOILS Soil Type Slopes Erosion Potential Erosive Velocities 10% - �o% _---- — �—BPS 0 Additional Sheets Attatched 1/90 4 Page 2 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET • • • REFERENCE LIMITATION/SITE CONSTRAINT �] Ch.4=Downstream Analysis Z 0 [] B t c-Ft l ya.�t crv� S`w u�2 ve-r- oo 0 t Y`\ 12 1,V 10 S - •Fri t C. 0 0 0 0 Additional Sheets Attatched PART 9 ESC REGUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION FOLLOWING CONSTRUCTION Sedimentation Facilities Stabilize Exposed Surface Stabilized Construction Entrance Remove and Restore Temporary ESC Facilities �^ Perimeter Runoff Control Clean and Remove All Silt and Debris Clearing and Grading Restrictions Ensure Operation of Permanent Facilities Cover Practices Flag Limits of NGPES Construction Sequence 0 Other 0 Other Grass Lined Channel 0 Tank 0 Infiltration Method of Analysis Pipe System 0 Vault 0 Depression S51 I" 0 Open Channel 0 Energy Dissapator 0 Flow Dispersal Compensation/Mitigation 0 Dry Pond 0 Wetland 0 Waiver of Eliminated Site Storage 0 Wet Pond 0 Stream /r 0 Regional Detention Brief Description of System Operation _paj ej 00-y-k na w t+k C_r�wns_tn+v_-C+b-- �L i��� Y� ffi Facility Related Site Limitations � 0 Additional Sheets Attatched Reference Facility Umitation (May require special structural review) Atrainage Easement X Cast in Place Vault 0 Other 0 Access Easement Retaining Wall 0 Native Growth Protection Easement Rockery>4'High 0 Tract 0 Structural on Steep Slope 0 Other PART 14 SIGNATURE OF • • • I or a civil engineer under my supervision have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attatchments. To the best of my knowledge the Information provided here Is accurate. 1/90 5 III . EXISTING DRAINAGE CONDITIONS The existing drainage is basically a combination of sheet flow and shallow channel flow down the several banks and benches towards the east property line, or Rainier Ave . The drainage analysis considered only the area that will be used for the development . There is a considerable area along the south and west property lines that is too steep to develop, and is not within the commercial zone . In the developed condition, the drainage from this area will be diverted around the development and will not enter the drainage system. Thus, the 7 . 57 acre total site area is reduced to 4 . 11 acres after this undisturbed area is subtracted. This "project area" is the same for the developed conditions calculations . The existing site has been previously disturbed by extensive grading for a gravel/sand mining operation. The north, east and central areas, which are the proposed development areas, do not have any trees . The vegetation is predominantly short grasses and scrub shrubs . . The existing drainage analysis was performed using the SBUH hydrograph method and the "Waterworks" hydrology software . The methods outlined in the 1990 King County Surface Water Design Manual were uses as guidelines . Following this page is the data sheets used for the computer input data . The computer summary sheets for the peak flow and time of concentration are also attached. Below is a brief summary of the existing conditions drainage characteristics : Time 'of concentration: 30 . 82 minutes 2 year peak flow: 0 . 46 CFS 10 year peak flow: 1 . 02 CFS 100 year peak flow: 1 . 72 CFS pervious area: 4 . 11 acres CN: 85 impervious area: none 69 ___ RD_�GRc�w tom► __ .TS _ "�� (5e� De.�-10�e� Dw�,,v�c►��s� C�.�1 c s 3- e-c7� Ny;-�cn- -7 , S1 - 3, (D 4 - 11 � OM W\4-V t �� Care 4\4t,�--bp.d 6y p S va C�-CAI V t t-1 e s C v-\I v\ (ToVe- o�, re TC (L - tv D : 5 07D 11 �O L TC = 30, 13 rn i h s Qe, c v v r sU rn rn a vy s OF C-�r��,NTR1oN ca�h� Z - Tc.7 r Cho-N�Y��1 t-1vwj 2. Yl r Q�T �2. ► 40 ' sl��-�10�..� �n�v�l Ito 0 ,Cv 9 M�n C s e e, c�,�rv��tt�r- su w�►�n�� io PZs = 3 4 �. ��►� �E - p���� �P.� FLoWs Z = 0,4co cis Jaeger Engineering page Renton Crown Apartments Drainage Analysis • Predeveloped Hydrograph Summaries BASIN SUMMARY BASIN ID: A10 NAME : Predeveloped, 10 year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 4 . 11 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 TIME OF CONC. . . . . : 30 . 82 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 00 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 300 . 00 ns : 0 . 2400 p2yr: 2 . 00 s : 0 . 0500 TcReach - Shallow L: 140 . 00 ks : 9 . 00 s : 0 . 1430 PEAK RATE : 1 . 02 cfs VOL: 0 . 52 Ac-ft TIME : 480 min BASIN ID: A100 NAME : Predeveloped, 100 year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 4 . 11 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 • TIME OF CONC . . . . . : 30 . 82 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 00 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 300 . 00 ns : 0 . 2400 p2yr: 2 . 00 s : 0 . 0500 TcReach - Shallow L: 140 . 00 ks : 9 . 00 s : 0 . 1430 PEAK RATE : 1 . 72 cfs VOL: 0 . 81 Ac-ft TIME : 480 min BASIN ID: A2 NAME: Predeveloped, 2 year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 4 . 11 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 4 . 11 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 85 . 00 TIME OF CONC. . . . . : 30 . 82 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 00 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 300 . 00 ns : 0 . 2400 p2yr : 2 . 00 s : 0 . 0500 TcReach - Shallow L: 140 . 00 ks : 9 . 00 s : 0 . 1430 PEAK RATE : 0 . 46 cfs VOL: 0 . 27 Ac-ft TIME : 480 min 17 File Basin Hydrograph Storage Discharge Level pool 3eee5eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ; eeeeeeeeee; ° SHEET FLOW CALCULATOR - INITIAL 300 FEET ° ° ° ° ° oDESoMannings Sheet Flow. . . . . : 0 . 2400 —Fc ) °HOICES ° ARE Flow Length (ft) . . . . . . . . : 300 . 00 °RAI02 yr 24 hr rainfall (in) : 2 . 00 ° ° °TIM°Land Slope (ft/ft) . . . . . . : 0 . 0500 ° ° °TIM° COMPUTED TRAVEL TIME (min) : 6ED ° ° °RAI° TYPICAL MANNINGS VALUES FOR INITIAL 300 FT °A ° °ABS° ° ° °BAS°Smooth Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . 011 ° ° °STO°Fallow Fields of Loose Soil Surface . . . . . . . . . . . . . . : 0 . 05 °Y ° ° °Cultivated Soil with residue cover (s<=0 . 2 ft/ft) : 0 . 06 ° ° °PER°Cultivated Soil with residue cover (s>0 . 2 ft/ft) . : 0 . 17 0 ° °ARE°Short prairie grass and lawns . . . . . . . . . . . . . . . . . . . . . 0 . 15 0 ° °CN °Dense grasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . 24 ° ° ° °Bermuda grass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 .41 ° ° • °Range (natural) . . . . . 0 . 13 ° ° °PEA°Woods or forest with light underbrush. . . . . . . . . . . . . 0 . 40 ° ° °PEA°Woods or forest with dense underbrush. . . . . . . . . . . . : 0 . 80 ° ° °TOT° ° ° 00F10Key: QUIT F5Key: CLEAR °ete ° Pgaeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeefit ° �eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef File Basin Hydrograph Storage Discharge Level pool 46 eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee; INPUT, MODIFY OR BROWSE DATA ° 5eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee; ° °DES° SHALLOW CONCENTRATED FLOW CALCULATOR ° ° °ARE° T ° ° °RAI°Flow Length (ft) . . . . 140 . 00 1 C 2 ° ° °TIM°Land Slope (ft/ft) . : 0 . 1430 ° ° °TIM°Kc, Velocity Factor: 9 . 0 ° ° °RAI° COMPUTED TRAVEL TIME (min) : (: 069 ° ° °ABS° TYPICAL VELOCITY FACTOR VALUES - R=0 . 1 ° ° °BAS° ° ° °STO°Forest with heavy ground litter and meadows (n=0 . 10) . . 3 ° ° °Brushy ground with 'some trees (n=0 . 060) . . . . . . . . . . . . . . . °' 5 ° ° °PER°Fallow or minimum tillage cultivation (n=0 . 04) . . . . . . . : 8 0 ° °ARE°High grass (n=0 . 035) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 ° ° °CN °Short grass, pasture and lawns (n=0 . 030) . . . . . . . . . . . . . : 11 ° ° • °Nearly bare ground (n=0 . 025) . . . . . . . . . . . . . . . . . . . . . . . . . . 13 0 ° ° °Paved and gravel areas (n=0 . 012) . . . . . . . . . . . . . . . . . . . . . . 27 ° ° °PEA° ° ° 0PEA0F10Key: QUIT F5Key: CLEAR ° ° °TOTaeeee2eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef ° ° HOME END F1 : Find F2 :New F3 :Get F4 :Tc-Calc F5 :Delete ° ° Pgup Pgdn F6 :Compute F7 : F8 :Method F9 :Template F10 :Exit ° aeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef E�E�r E-4-0 PE-0 T1,-'E- or Co"CE'N-VR"o N �O IV. DEVELOPED DRAINAGE CONDITIONS The developed site will incorporate a network of catch basins and interconnecting piping within the parking lots and driveways . The pavement will be constructed with a negative crown to channel the runoff into the central catch basins . The roof and footing drains from the structures will be connected to the storm drain system. Numerous yard drain inlets will be strategically placed within the lawn areas to collect yard runoff . The collected runoff will be piped to the northeast -property corner, to a precast concrete detention vault . This vault will include an orifice type flow restrictor. The flow restrictor will discharge into the biofiltration swale located in the northwest corner. Similar to the existing conditions drainage analysis, the SBUH hydrograph method will be used to determine the peak flow rates . An identical total area was also used. There will be a small bypass area along the low, west prop . line . The developed bypass flow from this area will be calculated • and subtraced from the allowable release rate . The computer data input sheets follow this page as well as the computer summary sheets . A brief summary of the developed drainage characteristics are : VAULT INFLOW BASIN: Basin area: 3 . 70 acres Time of concentration: 11 . 31 minutes 2 year peak flow: 1 . 34 CFS 10 year peak flow: 2 . 11 CFS 100 year peak flow:' 2 . 99 CFS pervious area: 1 . 15 acres CN: 86 impervious area: 2 . 55 acres CN: 98 BYPASS BASIN: Basin area: 0 .41 acres Time of concentration: 6 .44 minutes 2 year peak flow: 0 . 15 CFS 10 year peak flow: 0 . 24 CFS 100 year peak flow: 0 . 34 CFS pervious area: 0 . 17 acres CN: 86 • impervious area: 0 . 24 acres CN: 98 • ��I�L.OP�tJ p R�-�t.1��E GA:L cv L. Tl o tit S t� _ . ©Ns(Te, hRSA po"D �1 . NR�R 1 . Tote- d e- p-e. 329) 9 S-4- s F nof- d' A (� S1 C�h-eon v.� WIII 6e. 15�r61r AR so(zZ{✓-� _ g 4- 44) Z .S 4 „11 �.25s year c�reo` ; 0, 41 S . CuRv� N�mB�s I . To+a l Po--r\cQ .s a� b�flI I j tvt s : 4- f /r 50 S>= b) ()c �, '19, �r•vewe.�s'. �e(ol e� SF c Walk O-9N s : �300 sue. lb{ti�l = f 1 I , o(�� s F = 2,55' /4 c . rv� DuS- stsr l o,�A5-C I-ej I v ,-70 "e C , Tire ��,� o•�- .,SS ( l�u.,h� 6�.�.�-, lit� , � JA 1 70 • Tc 10 ,?5- - M i V\ , (see. c c� u1 CoA 51�-4 � P 6 J �y �„� d -. vo"i , i rt, L 2- � v a - �(oo' ei P� IOC -7 y- 4( - 3 (o 0 kc = 4-Z ( P,P� , Tab(� 3,s Z c TC Z = O, Sic M i h , C sec, s I +. i R �ti caRowr� I)Rp*\"Pv6 C-A-L C-s D. T 1D PLW► r\Ls 6:�- F.� PZ = 2 ,C) Flo Pzs - 3, a- Pion ' PEPf►- D�VEL.JPEt> R-DWS w s • i 'f Jaeger Engineering Renton Crown Apartments Drainage Calculations • Developed, Pond Hydrograph Summaries BASIN SUMMARY BASIN ID: B10 NAME : Developed, Pond, 10 year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 3 . 70 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 1 . 15 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 11 . 31 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 2 . 55 Acres CN. . . . . 98 . 00 TcReach - Sheet L: 70 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0140 TcReach - Channel L: 360 . 00 kc : 42 . 00 s : 0 . 0650 PEAK RATE : 2 . 11 cfs VOL: 0 . 72 Ac-ft TIME: 480 min BASIN ID: B100 NAME : Developed, pond, 100 year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 3 . 70 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . .. . . USER1 PERVIOUS AREA-- PRECIPITATION. . . ..: 3 . 90 inches AREA. . : 1 . 15 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 11 . 31 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 2 . 55 Acres CN. . . . . 98 . 00 TcReach - Sheet L: 70 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0140 TcReach - Channel L: 360 . 00 kc :42 . 00 s : 0 . 0650 PEAK RATE : 2 . 99 cfs VOL: 1 . 01 Ac-ft TIME : 480 min BASIN ID: 82 NAME: Developed, pond, 2 year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 3 . 70 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 1 . 15 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 11 . 31 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 2 . 55 Acres CN. . . . . 98 . 00 TcReach - Sheet L: 70 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0140 TcReach - Channel L: 360 . 00 kc:42 . 00 s : 0 . 0650 PEAK RATE : 1 . 34 cfs VOL: 0 . 46 Ac-ft TIME : 480 min /s File Basin Hydrograph Storage Discharge Level pool 5eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ; eeeeeeeeee4 ; ° SHEET FLOW CALCULATOR INITIAL 300 FEET 0 0 0 0 0 0 °DES°Mannings Sheet Flow. . . . . : 0 . 1500 ° ° °ARE°Flow Length (ft) . . . . . . . . . 70 . 00 �G ( °HOICES ° °RAI12 yr 24 hr rainfall (in) : 2 . 00 ° ° °TIM°Land Slope (ft/ft) . . .. . . . : 0 . 0140 ° °TIM° COMPUTED TRAVEL TIME (min) : 10 . 75 ° °RAI° TYPICAL MANNINGS VALUES FOR INITIAL 300 FT °A ° °ABS° 0 0 °BAS°Smooth Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . 011 ° ° °STO°Fallow Fields of Loose Soil Surface . . . . . . . . . . . . . . : 0 . 05 °Y ° °Cultivated Soil with residue cover (s<=0 . 2 ft/ft) : 0 . 06 ° ° °PER°Cultivated Soil with residue cover (s>0 . 2 ft/ft) . : 0 . 17 0 ° °ARE°Short prairie grass and lawns . . . . . . . . . . . . . . . . . . . . . 0 . 15 ° ° °CN °Dense grasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . 24 0 0 0 OBermuda grass . . . . . . 0 . 41 0 0 0 °Range (natural) . . . . 0 . 13 0 0 °PEA°Woods or forest with light underbrush. . . . . . . . . . . . : 0 . 40 ° ° °PEA°Woods or forest with dense underbrush. . . . . . . . . . . . : 0 . 80 ° ° °TOT° 0 0 00F10Key: QUIT F5Key: CLEAR °ete ° Pgaeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeefit ° �eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef File Basin Hydrograph Storage Discharge Level pool 5eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ; ee; ° CHANNEL FLOW CALCULATOR 0 0 0 0 0 0 °DES°Flow Length (ft) ._. . . 360 . 00 1 G Z 0 0 °ARE°Land Slope (ft/ft) . . 0 . 0650 0 0 °RAI°Kc, Velocity Factor: 42 . 0 0 0 °TIM° COMPUTED TRAVEL TIME (min) : (0D_ 56 ° ° °TIM° TYPICAL VELOCITY FACTOR VALUES 0 0 °RAI° 0 0 °ABS° Intermittent Flow - R=0 . 2 0 0 °BAS°Forested swale w/ heavy ground litter (n=0 . 10) . . . . . . . . . . . . . . . . . : 5 0 ° °STO°Forested drainage course/ravine w/ defined channel bed (n=0 . 50) : 10 ° ° °Rock-lined (n=0 . 035) . . . : 15 Grassed (n=0 . 030) . . . : 17 1 ° °PER°Earth-lined (n=0 . 025) . . : 20 CMP pipe (n=0 . 024) . . : 21 ° ° °ARE°Concrete pipe (n=0 . 012) : 42 other. . . . . . . . . . : 0 . 508/n 0 ° °CN ° Continous Flow - R=0 .4 0 0 ° °Meandering stream w/ some pools (n=0 . 040) . . . . . . . . . . . . . . . . . . . . . . . 20 ° ° ° °Rock-lined stream (n=0 . 035) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 0 ° °PEA°Grassed-lined stream (n=0 . 030) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 ° ° °PEA°Other streams, man-made channels and pipe . . . . . . . . . . . . . . . . . : 0 . 807/n 0 ° °TOT° 0 0 10F10Key: QUIT F5Key: CLEAR ° ° Pgaeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef ° aeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef D eu eA o-f-e-3 Tk"-e- , P- DR( v-i w C cA "T). Low r--R ES +Ale- -?aOD SF. 0 (0 op C- ec� C>+ u n A4 F> k T- ox-e-c,,- ,-o t kc-, I&J-ji ol.a,,,� r) = ol �z AEG Cr I i-I C�l ux S+1:5�C-,P— L I 'Z s6-Q+ 4' o-t ecst- c-,or n-Q� i oi� o-rJ 4 Res- 4, Sl TG� (!?,OS m�nv{�S Seer Gdm��s��� co ��T)ztoo flfp- -plo"i 4:�Z� yc.,� jm-k" 7 Zo 3 Jr) T,-- " Tc Lo - +4- V\\nu+e--5- 17 D�v�oPc-p �DR�-i Nr�� ( �►�-� .. (CD�T) p. �SOPLyVI ►� LS ( �� �� 3. � . 1) M—n y ?�qr�wL 2 h S ML'H]o Flo" 3 i s QIw V 0. 3d Gas Jaeger Engineering Renton Crown Apartments Drainage Calculations Developed Bypass Hydrograph Summaries BASIN SUMMARY BASIN ID: By10 NAME: Bypass, developed, 10 year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0 . 17 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC . . . . . : 6 .44 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 24 Acres CN. . . . . 98 . 00 TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr : 2 . 00 s : 0 . 0300 TcReach - Channel L: 260 . 00 kc :42 . 00 s : 0 . 0700 PEAK RATE : 0 . 24 cfs VOL: 0 . 08 Ac-ft TIME : 470 min BASIN ID: By100 NAME: Bypass, developed, 100 year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 17 Acres TIME INTERVAL. . . 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 6 . 44 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 24 Acres CN. . . . : 98 . 00 . TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0300 TcReach - Channel L: 260 . 00 kc :42 . 00 s : 0 . 0700 PEAK RATE : 0 . 34 cfs VOL: 0 . 11 Ac-ft TIME : 470 min BASIN ID: By2 NAME: Bypass, developed, 2 year SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 .41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 . 17 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 6 .44 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 24 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 0300 TcReach - Channel L: 260,. 00, kc :42 . 00 s : 0 . 0700 PEAK RATE: 0 . 15 cfs VOL: 0 . 05 Ac-ft TIME: 480 min 1�3y ass 7'rl ",jU a-f CeM File Basin Hydrograph Storage Discharge Level pool 3eee5eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ; eeeeeeeeee; ° SHEET FLOW CALCULATOR - INITIAL 300 FEET ° ° ° ° ° °DES°Mannings Sheet Flow. . . . . : 0 . 1500 ° ° °ARE°Flow Length (ft) . . . . . . . . : 50 . 00 G °HOICES ° °RAI02 yr 24 hr rainfall (in) : 2 . 00 ° ° °TIM°Land Slope (ft/ft) . . . . . . : 0 . 0300 ° ° °TIM° COMPUTED TRAVEL TIME (min) : G . 05 ° ° °RAI° TYPICAL MANNINGS VALUES FOR INITIAL 300 FT °A ° °ABS° ° ° °BAS°Smooth Surfaces . ; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . 011 ° ° °STO°Fallow Fields of Loose Soil Surface . . . . . . . . . . . . . . : 0 . 05 °Y ° ° 'Cultivated Soil with residue cover (s<=0 . 2 ft/ft) : 0 . 06 0 ° °PER°Cultivated Soil with residue cover (s>0 . 2 ft/ft) . : 0 . 17 ° ° °ARE°Short prairie grass and lawns . . . . . . . . . . . . . . . . . . . . . 0 . 15 ° ° °CN °Dense grasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . 24 ° ° ° °Bermuda grass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 .41 ° ° ° °Range (natural) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . 13 ° ° °PEA°Woods or forest with light underbrush. . . . . . . . . . . . : 0 .40 0 ° °PEA°Woods or forest with dense underbrush. . . . . . . . . . . . : 0 . 80 0 ° °TOT° ° ° 00F10Key: QUIT F5Key: CLEAR °ete ° Pg�eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeefit ° aeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef File Basin Hydrograph Storage Discharge Level pool 4lieee5eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ; ee; ° CHANNEL FLOW CALCULATOR ° ° °DES°Flow Length (ft) . . . : 260 . 00 �G 2 ° ° °ARE°Land Slope (ft/ft) . . 0 . 0700 ° ° °RAI°Kc, Velocity Factor: 42 . 0 ° ° °TIM° COMPUTED TRAVEL TIME (min) : 0 . 39 ° ° °TIM° TYPICAL VELOCITY FACTOR VALUES ° ° °RAI° ° ° °ABS° Intermittent Flow - R=0 . 2 ° ° °BAS°Forested swale w/ heavy ground litter (n=0 . 10) . . . . . . . . . . . . . . . . . : 5 0 ° °STO°Forested drainage course/ravine w/ defined channel bed (n=0 . 50) : 10 ° ° °Rock-lined (n=0 . 035) . . . : 15 Grassed (n=0 . 030) . . . : 17 0 ° °PER°Earth-lined (n=0 . 025) . . : 20 CMP pipe (n=0 . 024) . . : 21 0 ° °ARE°Concrete pipe (n=0 . 012) : 42 other. . . . . . . . . . : 0 . 508/n ° ° °CN ° Continous Flow - R=0 . 4 0 ° ° °Meandering stream w/ some pools (n=0 . 040) . . . . . . . . . . . . . . . . . . . . . . : 20 ° ° ° °Rock-lined stream (n=0 . 035) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 0 ° °PEA°Grassed-lined stream (n=0 . 030) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 ° °PEA°Other streams, man-made channels and pipe . . . . . . . . . . . . . . . . . : 0 . 807/n ° °TOT° .. ° ° 00F10Key: QUIT F5Key: CLEAR 0 ° Pgaeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef ° �eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef File Basin Hydrograph Storage Discharge Level pool eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee; INPUT, MODIFY OR BROWSE DATA ° ° BASIN ID E10 SBUH HYDROGRAPH ° °DES4eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ; ° °ARE° TIME OF CONC WORKSHEET °NFALL CHOICES ° °RAI° <----Tc Reach Type----> Tt (min) °TYPE IA 0 Zo V. DETENTION STORAGE SIZING The detention vault was sized to retain the developed 2 year and 10 year storms while discharging at a rate not more than the 2 year and 10 year predeveloped peak flow rates . The developed flows from the bypass area were subtracted from the allowable release rates . Once the vault was sized using the level pool analysis, the volume was increased by 30o as required in the drainage code . The vault performance is as follows : STORM PREDEV FLOW BYPASS FLOW VAULT RELEASE 2 year 0 . 46 CFS 0 . 15 CFS 0 . 31 CFS 10 year 1 . 02 CFS 0 . 24 CFS 0 . 78 CFS The vault calculated to be 61 . 5 ft . by 28 . 0 ft . Adding the 30% factor increases the required length to 80 ft . BIOFILTRATION SWALE The biofiltration swale was designed using the King County SWM Manual criteria . The vegetation type within the swale will be grasses type, as allowed in the manual for actual swale slopes of 0 . 5% or less . This type of swale vegetation specifies a design water depth of 41, within the swale . The bottom width of the swale was determined using the 2 year vault release flow of 0 . 31 CFS . The required bottom width was calculated to be 2 . 88 ft . with 3 : 1 side slopes . The swale length will be 150 ft . The velocity at these conditions is 0 . 24 FPS, less than the maximum 1 . 5 FPS . Because the swale length will be reduced to 150 ft . , the swale width will accordingly be increased to 4 . 5 ft . The swale was also checked for capacity during a 100 year developed flow rate . Its actual slope of 0 . 5% was used. The resultant depth of flow was 0 . 35 ft . , which would be contained by a 1 ft . deep swale . The computer calculation sheets for the bioswale are attached. Z.l File Basin Hydrograph Storage Discharge Level pool Jaeger Engineering 2eeeee-eeeeeeeeeeee; eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ; ° ROUTING COMPARISON TABLE ° ° MATCH INFLOW STO DIS PEAK PEAK OUT ° ° DESCRIPTION PEAK PEAK No. No. STG OUT HYD ° ---------------------------------------------------------------------- °2 year 0 . 46 1 . 34 1 1 49 . 03 0 . 31 11 ° 010 year 1 . 02 2 . 11 1 1 50 . 36 0 . 78 12 0 ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ______====>Done<====_-_____= F10 to Exit ° d22eeee2222222E22Eee22222222222eee2eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee2222Ef There may not be enough memory to do large LPool routings Available Memory remaining: 52440 bytes Current Data Set Name : \CROWNAPT.bsn 4/ 8/97 Jaeger Engineering page 1 Renton Crown Apartments Drainage Calculations Level Pool Analysis, 2 and 10 year storms --------------------------------------------------------------------- --------------------------------------------------------------------- LEVEL POOL TABLE SUMMARY MATCH INFLOW ST DI <-PEAK-> STORAGE <--------DESCRIPTION---------> (cfs) (cfs) id id <-STAGE> id VOL (cf) ----------------------------------------------------------------------- ----------------------------------------------------------------------- 2 year . . . . . . . . . . . . . . . . . . . . . . . 0 . 46 1 . 34 1 1 49 . 03 11 4879 . 16 10 year . . . . . . . . . . . . . . . . . . . . . . 1 . 02 2 . 11 1 1 50 . 36 12 7165 .42 L(31 -s Zz File Basin Hydrograph Storage Discharge Level pool J2eeeeeeeeeeeeeeeeeeeeee ; 0 0 °Rectangular vault ' °Trapezoidal basin 0 °Underground pipe 0 OSto list 0 3eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ; O RECTANGULAR VAULT O O O STORAGE STRUCTURE ID: 1 0 0 0 0eeeeef OName . : Detention Vault / 1 . 3 0 OLength (ft) . . . . . . . . : 61 . 50 0 OWidth (ft) . . . . . . . . . . 28 . 00 0 OStarting Elevation. : 46 . 20 0 OMax Elev of Vault . . : 53 . 00 0 OStage-Sto Increment : 0 . 10 0 OStructure Vol (cf) . : 11709 . 60 0 0 Ac-ft . : 0 . 27 0 0 0 'PGUP PGDN F3 : Get F6 : Delete F10 : Exit O aeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef There may not be enough memory to do large LPool routings Available Memory remaining: 52440 bytes Current Data Set Name : \CROWNAPT.bsn File Basin Hydrograph Storage Discharge Level pool eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ; MULTIPLE ORIFICE ' 0 DISCHARGE STRUCTURE ID: 1 0 0 0 OName: Flow Restrictor 'Peak Dsgn Release Rate : 0 . 78 cfs Orif /flow/elev 0 'Orifice Coefficient . . . : 0 . 62 Dia (in) /cfs/ ft 0 'Lowest Orifice Dia (in) . . : 2 . 62 2 . 62 0 . 38 cfs 0 Ohl : Outlet to 2nd Orifice : 2 . 90 49 . 10 ft O 'Second Orifice Dia (in) . . . 3 . 63 3 . 62 0 .40 cfs O Oh2 : 2nd to 3rd Orifice . . . : 0 . 00 'Third Orifice Dia (in) . . : 0 . 00 O 'h3 : 3rd to 4th Orifice . . . : 0 . 00 0 'Fourth Orifice Dia (in) . . . 0 . 00 ��� 0 Oh4 : 4th to 5th Orifice . . . : 0 . 00 oTop Orifice Dia (in) . . . 0 . 00 �`� 1 Cj °Elevation of Lowest Orifice . . . . : 45 . 20 ' 00utlet Elevation. . . . . . . . . . . . . . . . 46 . 20 0 'Max Elev Above Outlet . . . . . . . . . . . 50 . 36 0 OStage-Disch Increment . . . . . . . . . . . 0 . 10 O ThO ' AvOPGUP PGDN F3 : Get F6 : Delete F10 : Exit O Cu�eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeef - ---- ---- ---------- 0 .G� sF � o� z . P ew rove + 7- f 'r- = z z,14 oaF I � y 2_c-)0 3`� FT 3 Pt �. s �� its P�o uIJ-.Q-eO KING COUNTY, WASIIINGT' ON, SURFACE WA '1' rR D1" SIGN MANUAL 1.3.5 SPECIAL REQUIREMENT M SPECIAL WATER QUALITY CONTROLS Threshold Requirement IF any threshold discharge area" of THEN the threshold discharge area" the proposed project contains more shall have a wetpond meeting the than 1 acre of new impervious standards described below employed surface that will be subject to (in addition to peak rate control vehicular use or storage of chemicals requirements) to treat a o oject's and: runoff prior to discharge from the site. A wetyault or water quality swale, as (a) proposes direct discharge of described below, may be used when a runoff to a regional facility, wetpond is not feasible because of receiving water, lake, wetland, or physical site constraints or impacts to closed depression without on-site sensitive areas. peak rate runoff control; OR (b) proposes discharge of runoff through overland flow or on-site infiltration into a Class 1 or 2 stream, or Class 1 wetland, within one mile radius downstream from ALLe_nroiect site. Wetponds or Wetvault Wetponds and Wetvaults contain a permanent pool of water depending on the frequency and quantity of inflow, and (for Wetponds) the rate of permeability of the underlying soil. The Wetponds and Wetvaults fill with the initial onset of frequent storms such that the major portion of the volume of runoff is treated. The principal mechanism of treatment is settlement due to establishment of calm conditions. In Wetponds treatment is enhanced by the mechanisms of biofiltration and biologic activity. The size (water surface area and volume) of the Wetpond or Wetvaults shall be determined as follows: (1) T-he design water surface area in the Wetpond or Wetvault shall be a rninimurn of one percent of the impervious surface area in the drainage sub-basin contributing to the facility. (2.) The design volurne of the Wetpond or Wetvault shall be a minirnurn of the total volume of runoff (see Chapter 3: Ilydrologic Analysis) from the tributary sub-basin proposed developed conditions using a water quality design storm event having a total precipitation (Pt-wq), where f t-wq is one-third of the two-year, 24-hour total precipitation (P2/3, P2 is obtained from figure 3.S.1 C). This water quality design storm event approximates the runoff from the mean annual storm event. Other design critelria are found in Section 4.6.2. " A threshold discharge area is an on site area which drains to a single natural discharge location or multiple natural discharge locations that combine within 1/4 mile downstream. 11/92 zs Trapezoidal Channel Analysis & Design Open Channel - Uniform flow Worksheet Name : Renton Crown Apts Comment : Biofiltration Swale, Design Conditions Solve For Bottom Width Given Input Data: Left Side Slope . . 3 . 00 : 1 (H:V) Right Side Slope. 3 . 00 : 1 (H:V) Manning' s n. . . . . . 0 . 350 Channel Slope . . . . 0 . 0200 ft/ft Depth. . . . . . . . . . . . 0 . 33 ft Discharge . . . . . . . . 0 . 31 cfs Computed Results : Bottom Width. . . . 2 . 88 ft Velocity. . . . . . . . . 0 . 24 fps Flow Area. . . . . . . . 1 . 28 sf Flow Top Width. . . 4 . 86 ft Wetted Perimeter. 4 . 97 ft `-- Critical Depth. . . 0 . 07 ft Critical Slope . . . 4 .4830 ft/ft Froude Number. . . . 0 . 08 (flow is Subcritical) ck CJ I Le I Sc� 4-Soy Open Channel Flow Module, Version 3 . 12 (c) 1990 Haestad Methods, Inc . * 37 Brookside Rd * Waterbury, Ct 06708 Z� Trapezoidal Channel Analysis & Design Open Channel - Uniform flow Worksheet Name : Renton Crown Apts Comment : Biofiltration Swale, 100 year actual cond. Solve For Depth Given Input Data: Bottom Width. . . . . 4 . 50 ft Left Side Slope . . 3 . 00 : 1 (H:V) Right Side Slope . 3 . 00 : 1 (H:V) Manning' s n. . . . . . 0 . 030 Channel Slope . . . . 0 . 0050 ft/ft Discharge . . . . . . . 2 . 99 cfs Computed Results : Depth. . . . . . . . . . . . 0 . 35 ft Velocity. . . . . . . . . 1 . 53 fps Flow Area. . . . . . . . 1 . 95 sf Flow Top Width. . . 6 . 61 ft Wetted Perimeter. 6 . 72 ft Critical Depth. . . 0 . 23 ft Critical Slope . . . 0 . 0228 ft/ft Froude Number. . . . 0 . 50 (flow is Subcritical) Open Channel Flow Module, Version 3 . 12 (c) 1990 Haestad Methods, Inc . * 37 Brookside Rd * Waterbury, Ct 06708 Z7 CATCH BASIN SCHEDULE Elevations CB No . Type Rim Inv. 1 I I-4 8 solid lock lid 58 . 0 46 . 05 2 I-48" 53 . 5 46 . 6 , 50 . 5 (W, SE) 2A YD 54 . 5 51 . 3 2B YD 54 . 0 52 . 0 3 I 51 . 0 47 . 6 4 I 51 . 0 48 . 5 5 II-48" 61 . 3 53 . 1, 58 . 1 (E, S) . 5A I 56 . 0 54 . 0 5B YD 64 . 0 60 . 5 5C YD 63 . 5 61 . 5 6 I 69 . 0 64 . 1 6A YD 69 . 5 65 . 1 6B YD 69 . 5 67 . 5 6C YD 69 . 5 67 . 5 7 I 76 . 5 74 . 0 7A YD 79 . 0 77 . 0 8 I 83 . 0 80 . 0 9 I 58 . 0 55 . 5 10 -I 64 . 5 62 . 0 10A I' 65 . 0 62 . 5 10B YD 69 . 0 66 . 5 11 I 69 . 7 67 . 0 11A YD 72 . 5 70 . 0 12 I 62 . 0 59 . 5 12A YD 61 . 5 59 . 8 13 I 72 . 0 69 . 5 13A YD 74 . 0 71 . 5 13B YD 75 . 0 72 . 5 14 I 38 . 5 36 . 0 15 I 39 . 0 36 . 5 16 I I-4 8"solid lock lid . 46 . 5 37 . 0 44 .v(51 16A YD 54 . 5 52 . 0 A I I-5 4 solid lock lid 63 . 0 51 . 3 B I I-5 4„solid lock lid 72 . 0 58 . 6 C I I-5 4"solid lock lid 72 . 5 59 . 3 ze DRAINAGE PIPE SCHEDULE Segment Dia. (in. ) Length (ft . ) %Slope ExCB - Bioswale 18 10 1 . 0 Bioswale - CB1 18 30 1 . 0 CBI - Vault 18 15 1 . 0 Vault - CB2 12 8 5 . 0 CB2 - CB3 12 67 1 . 5 2A - CB2 8 40 2 . 0 2B - 2A 8 37 2 . 0 CB3 - CB4 12 73 1 . 2 CB4 - CB5 12 110 4 . 2 5A - CB5 8 86 1 . 0 5B - CB5 8 40 5 . 5 5C - 5B 8 50 2 . 0 CB5 - CB6 12 120 5 . 0 6A - CB6 8 50 2 . 0 6B - 6A 8 43 2 . 0 6C - CB6 8 65 5 . 2 CB6 - CB7 12 162 6 . 1 7A - CB7 8 42 7 . 1 CB7 - CBS 12 158 3 . 8 CB9 - CB2 12 94 5 . 3 CB10 - CB9 12 92 7 . 1 10A - CB10 12 17 2 . 9 10B - 10A 8 80 5 . 0 CB11 - CB10 12 72 6 . 9 11A - CB11 8 97 3 . 1 CB12 - CB9 12 148 2 . 7 12A - CB12 8 12 2 . 5 CB13 - CB12 12 98 10 . 2 13A - CB13 12 27 7 . 4 13B - 13A 12 52 1 . 9 ExCB - CB14 12 60 2 . 5 CB14 - CB15 12 33 1 . 5 CB15 - CB16 12 25 2 . 0 16A - CB16 8 150 5 . 3 ExCB - CB'A' 36 136 5 . 18 CB'A' - CB'B' 36 140 5 . 18 CB' B' - CB' C" 36 14 5 . 18 ZI VI . OFF-SITE DRAINAGE ANALYSIS A. Analysis of Resources : Several resource materials were reviewed for the preparation of this analysis . These resources include : 1 . City of Renton drainage maps . 2 . USGS quadrangle topography maps 3 . King County sensitive areas folios . 4 . Engineering plans and reports for previous projects proposed for this site . B . Upstream Off-site Analysis The upstream off-site drainage onto the site is limited to the west and south property lines . The residential lots along the top of the banks along these property lines slope onto the property. The tributary area is limited to the strip of lots between the top of the bank and the adjoining residential street . Most of this runoff is rear yard sheet flow, but some downspout drainage is piped over the bank. This upstream flow is negligible given the small tributary areas . Any upstream flow that traverses the subject site would be intercepted by' thb proposed retaining wall along the south side or by the existing swale that runs along the toe of the bank along the west side . There is no upstream flows from the north or the east . The existing office complex to the north controls its drainage within its parking lot . Rainier Ave . is along the east line, which is downgradient from the site . C. Downstream Drainage The drainage from the site will discharge into the existing 36" CMP that runs west to east within the parking lot just north of the property. 12" pipe stubs have been run onto the site from the existing catch basins within this parking lot . The 36" pipe network is identified on the City of Renton drainage maps as the run from MH 11D5-4 to MH 11D5-12 . The site connection point will be near the latter MH. From this point, the drainage travels east across Rainier Ave . S . for approx. 320 ft . and onto the City of Renton Airport . The piping along this run is 36" concrete and CMP. At this point within the airport, the pipe tees into a 96" x 60" pipe that runs north along the west edge of the airport for approx. 1500 ft . before discharging into Lake Washington just west of the mouth of the Cedar River. EMTSOLS MANHOLE AND OUTLET PIPE INVENTORY SHEET 11 The inventory information for the storm drainage system was compiled from numerous sources and is the best information available at this time and should be used only for GENERAL guidance . The City of Renton is not responsible for errors or omissions when this information is used for engineering purpose. Designers are to field verify this information. DWN GRATE UPPER LOWER GRATE O/W PIPE PIPE STREAM PLAN STRUCTURE INDEX # TYPE CB ? IE IE IE TYPE SEP. DIAM. TYPE LENGTH STRUCT FILE MH 11,D 4 - 25 MOD4 y - - - C N 96X60 CC - - 13-1-39 MH 11,D 5 - 1 2 Y - - - C N 12 CC - 11,D5-2 4-4-254 MH 11,D 5 - 2 2 Y - - - C N 12 CC - 11,D5-3 4-4-254 MH 11,D 5 - 3 2 Y - - - C N 36 CMP - 11,D5-13 4-4-254 MH 11,13' 5 44 2 y 103.4 92.6 81.5 C N 36 CMP - 11,D5-5 CROWN-Pr---, MH 11,D 5 - 5 2 y 99.3 81.05 60.55 C N 36 CC 145 11,D5-6 CROWN PT MH 11,D 5 _- 6 2-54. y 68.57 60.55 53.94 C N 36 CC 228 11,D5-7 CROWN PT MR 11,D 5 - 7 2-54. y 62.55 53.94 51.76 C N 36- CC 75 11,D5-8 CROWN PT' MH 11,D 5 - 8 2-54. y 60.25 51.76 48.4 C N- 36 CC 116 11,D5-9 CROWN PT MH 11,D 5 - 9 2-48. Y 57 45.72 44.77 C N 36 CC 43 11,D5-10 CROWN PT MH 11,D 5 - 10 2-54. Y 55 41.77 37.8 C N 36 - - 11,D5-11 CROWN PT MH 11,D 5 - 11 2 Y 44.7 37.7 29.2 C N 36 CMP - 11,D5-12 CROWN Pr MH 11,D 5 - 12 2 y 37.15 28.68 - C N 36 CMP - 11,D5-3 CROWN POINT MH 11,D 5 - 13 VAULT y - - - C N 36 CMP - 11,E5-1 - MH 11,D 7 - 1 2 Y 146.7 136 - S N 18 - - OUT 17-1-1 MH 11,D 8 - 1 2 y - - - C N 12 CC - 11,D8-2 2-4-951 MH 11,D 8 - 2 2 Y 91.5 - - - N - - - - 2-4-951 MH 11,D 8 - 12 2 y - - - - N 18 CC - OUT - MH 11,E 5 - 1 - y - - - C N 96X60 CC - 11,D4-25 13-1-39 MH 11,E 5 - 2 - Y - 11.99 - C N 96X60 CC - 11,E5-1 13-139 MH 11,E 6 - 1 2 y - - - C N 12 CC - 11,D5-1 - MH 11,E 6 - 2 MOD4 Y - - - C N 84X60 CC - 11,E6-3 13-1-39 MH 11,E 6 - 3 MOD4 y - - 11.9 C N 84X60 CC - 11,E5-2 13-1-39 MH 11,E 7 - 1 2 y - - 17 c N 24 CMP - 11,E7-4 4-4-254 MH 11,E 7 - 2 2 y - - - C N 15 CC - 11,E7-1 4-4-254 MH 11,E 7 - 3 2 y - - - C N 12 CC - 11,E7-2 4-4-254 MH 11,E 7 - 4 - y - 14.17 - C N 84X60 CC - 11,E7-5 13-1-39 April , 1995 Page 2 �N C ' ILD3- S ^115TH i —vs t t sT — ------ I - 4oa t 3 p � � 1 =S11 I PL I > J1 CD ILD3-6 N / IIE3-1 • IL 1I EE:J ILD3-5 w ` Il i i y i I�11,11D3-3 1 1-1 . .17 111.D4-1 `1 1LD I3ALB I 1 �T ' I `F ILw- i'D4-2 11.D4_2 ILDa le 1i 1 1Lw-u W '1 w- 111.D Ip y/ 1Lw-26 Q `W% i I i E l i i + l 11bT 1 Q! 1 I 0 = cTIL - IL 22 1 S+ 11/TH I I '� I`�;11B4 7 LD4-2 1 I2LM11(D_54 6PLD4 I -I1.D4 :3 lLD4-25 ' J d Y~I D j 1 i lla-I ILD4-1 - ILD444 ' + BOEING IL115-10 1Ln II f 13 ILE5-I 1` 1 9TH co 1 ILL 3 '1 < i r IL55- IL 9 7r3 W s 1eo'H W_ i,T. I II I ILDS-2 t 1` -' - D5-co 5 lLES-2 • i i j ILOSIr4 1 1" s! W 3 B6-16 1186-18 1LC6-11 1LC -13 1LC6-161 _ Z ILB6-156 111j6 1 LC(�-10 L ( i I ♦� "I' 86F20 I i i i I r1 iL - ILC6-15; S j I 121TH I !ST! i 1,�T15-1 I'1 �r 1LB6-14 ' I 1 Cn ILE 6-3 11 i 1LC6 I I 11 1LB6-13 ST ILB6-I2 ILB6-7 I -9 II�6 6 i i I I j i RENTON MUNICIPAL AIRPORT w hQ 1LE6-1 1.26-hLC 1 1 I i ILB6- _ Nil' , NTH ST I i I I ILC6-41 y 9 LLB6-10 - S ST 1LB6- �....�•••�•••C6-3 1LC6-2 ¢ Z i i Z ILE6-2 11.BG-1I � D 1 i C7 ILB7-15 sI 12.DRD PL ! LLL�-IB 1 � 1LB7-9 L n-10 1137-12 ILB7-14 11B7-9B 17-18 � i i L lLB7-1I W ¢ ` ILB7-8 1 7-11 11.C7-17 ! W I \ 1I,E 7- ILE7-5 Is 1ST �T 1 -y ' \ LM . I 7- 6TH S L 7-9 11 - 1L ILB7-6 ILB7t16 I IL iL II.C7-3i I ILC7-11 1 7-5 ILC7 8 ilLc IILC7-2 I 6�N I 1ST ILB7-3 I I LC7 4 i ILB7-2 I t�T 11E7- J r T S 125 T ILB7-1 S L, I11D7-! '�► 11.E7-1 '1 t? LC7-15 :t07- C7-16. C 151 , 11 LLB8-1 8i I1.0_ ILBB-5 1 Ce-1 D IOB-lOe- I -I� �...�► `1 I8-8 ¢ ILA- LDB-1) �••• Q II.EB-3 LDB-12_ 2LD8-3 1.C8-I3 II.38-2 ILEB14 LC8-10 Z �1 . 3Z APPENDIX CHARTS , TABLES , GRAPHS 'FROM KING COUNTY SWM MANUAL KING COUN FT . �V \ SfII �' c; f �) N. til' R ( ;\ (' G W ,� T ER [) [= SIGN %1 GNU AL - --- --- - — - - - - --------------- - --- ------ --- ---- ----- - --- - - - ----- -- 7-ABLE 3.5.211 SCS %VES"I'ERN 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 1A 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: 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 81 88 92 94 Open spaces, lawns, parks, golf courses, cemeteries, landscaping. good condition: grass cover on 75% or more of the area 68 80 86 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 Impervinus clorfares, f2av r7t.,! r_21s, c•r Jv 08 nq -v im Open water bodies: lakes, wetlands, ponds, etc. 100 100 100 100 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 4, 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 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL iTABLE 3.5.2C "n" AND "k" VALUES USED IN TIME CALCULATIONS FOR HYDROGRAPHS -n,-Sheet Flow Equation Manning's Values(For the Initial 300 h of travel) n,` Smooth surfaces(concrete,asphalt,gravel,or bare hard packed soil) 0.011 Fallow fields or loose soil surface(no residue) 0.05 Cultivated sell with residue cover(s <- 0.20 h/ff) 0.06 Cultivated soft with residue cover(S>0.20 ft/h) 0.17 Short prairie grass and lawns 0.15 Dense grasses 0.24 Bermuda grass 0.41 Range(natural) 0.13 Woods or forest with light underbrush 0.40 Woods or forest with dense underbrush 0.80 'Manning values for sheet flow only,from Overton and Meadows 1976(See TR-55,1986) 'k'Values Used In Travel Time/Time of Concentration Calculations Shallow Concentrated Flow (After the Initial 300 ft.of sheet flow.R -0.1) k, 1. Forest with heavy ground litter and meadows(n-0.10) 3 2. Brushy ground with some trees(n-0.060) 5 3. Fallow or minimum tillage cultivation(n -0.040) 6 4. High grass(n -0.035) 9 5. Short grass,pasture and lawns(n-0.0.'V) 1 I B. Nearly bare ground(n-0.025) 13 7. Paved and gravel areas(n-0.012) 27 Channel Flow(Intermittent)(At the beginning of visible channels:R-0.2) k, 1. Forested Swale with heavy ground litter(n -0.10) 5 2. Foresled drainage course/ravine with defined channel bed(n-0.050) 10 3 Rock linedwaterway(n=0 035) 15 4. Grassed waterway(n-0.030) 17 5. Earth-lined waterway(n-0.025) 20 6. CMP pipe(n-0.024) 21 7. Concrete pipe(0.012) 42 8. Other waterways and pipes 0.508/n Channel Flow(Continuous stream,R -0.4) k. 9. Meandering stream with some pods(n-0.040) 20 10. Rock-lined stream(n-0.035) 23 II- Grass-lined stream(n-0.030) 27 • 12. Other streams,man-made channels and pips 0.807/n" -Sea Chapter 5,Table 5.3.6C for additional Mannings'n'values for open channels 3.5.2-7 I/90 .14 O . tea►n, � \ IN tllm :..� Imp AWN I I [Inv WTV 31.a • wltlikj PAV . � 1 s � � f • snA� ! w J ! f <. ` l