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Specifications 714-s��vl4 - (J()ILle- 6'?( ' c'i wa/G14t- RECEIVED MAY 122016 CITY OF TIGARD HYDROLOGIC CALCULATIONS BUILDING DIVISION Project location: 6810 SW Walnut Terrace, Tigard, OR 97223 May 3, 2016 Prepared for: Michael Vaugh Urban Revival, Ilc Tel: 503-45-9048 Fax: 503-523-2189 Prepared by: NW Civil Design, Ilc 9715 NE 100th Way Vancouver, WA 98662 Tel 360-607-0654 Fax 360-885-8366 `,0 PR°, �,�4y�CNsl N'�fi'psJ°� dir ORE v`N EXPIRES: I `3 - ��( OBJECTIVE: Find the peak flow for pump sizing. GIVEN: Roof Area: 2,873 sf = 0.066 ac Driveway Area: 3,254 sf = 0,075 ac Total Impervious area: 6,127 sf = 0.14 ac Curve Number (CN) = 98 Time of Concentration = 5 min Hydrologic Analysis Stormwater runoff rates and volumes were computed using Santa Barbara Urban Hydrograph (SBUH)program. These flow rates were determined for the 2-year, 10-year,25-year,and 100- year storm events. NRCS Type lA Rainfall Distribution: Recurrence Interval Total Precipitation Depth (years) (in) 2 2.50 10 3.45 25 3.90 100 4.50 Hydrologic Analysis Summary Table—Developed Conditions 24-hour BASIN PERV. CN IMPERV. CN Tc PEAK VOL storm AREA AREA (mi FLOW (cf) event (Ac) (Ac) n) (cfs) 2-YR 1 0 90 0.14 98 5 0.09 1153 10-YR 1 0 90 0.14 98 5 0.13 1634 25-YR 1 0 90 0.14 98 5 0.14 1862 100-YR 1 0 90 0.14 98 5 0.17 2166 Conclusion: Peak flow for pump sizing is 0.14 cfs (64 gpm) KING COUNTY DEPARTMENT OF PUBLIC WORKS Surface Water Management Division HYDROGRAPH PROGRAMS Version 4 .21B 1 - INFO ON THIS PROGRAM 2 - SBUHYD 3 - MODIFIED SBUHYD 4 - ROUTE 5 - ROUTE2 6 - ADDHYD 7 - BASEFLOW 8 - PLOTHYD 9 - DATA 10 - RDFAC 11 - RETURN TO DOS ENTER OPTION: 2 SBUH/SCS METHOD FOR COMPUTING RUNOFF HYDROGRAPH STORM OPTIONS: 1 - S.C.S. TYPE-1A 2 - 7-DAY DESIGN STORM 3 - STORM DATA FILE SPECIFY STORM OPTION: 1 S.C.S. TYPE-1A RAINFALL DISTRIBUTION ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP(INCHES) 2, 24,2.5 ******************** S.C.S. TYPE-1A DISTRIBUTION ******************** ********* 2-YEAR 24-HOUR STORM **** 2.50" TOTAL PRECIP. ********* ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN (IMPERV) , TC FOR BASIN NO. 1 0, 90, 0. 14, 98, 5 DATA PRINT-OUT: AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) A CN A CN .1 .0 90.0 .1 98 .0 5.0 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) .09 7. 67 1153 ENTER [d: ] [path] filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH: 2dev SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP n • STORM OPTIONS: 1 - S.C.S. TYPE-1A 2 - 7-DAY DESIGN STORM 3 - STORM DATA FILE SPECIFY STORM OPTION: 1 S.C.S. TYPE-1A RAINFALL DISTRIBUTION ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP(INCHES) 10, 24, 3.45 ******************** S.C.S. TYPE-1A DISTRIBUTION ******************** ********* 10-YEAR 24-HOUR STORM **** 3.45" TOTAL PRECIP. ********* ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1 0, 90, 0, 14, 98, 5 DATA PRINT-OUT: AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) A CN A CN .1 .0 90.0 .1 98.0 5.0 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) . 13 7. 67 1634 ENTER [d: ] [path] filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH: l0dev SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP n STORM OPTIONS: 1 - S.C.S. TYPE-1A 2 - 7-DAY DESIGN STORM 3 - STORM DATA FILE SPECIFY STORM OPTION: 1 S.C.S. TYPE-1A RAINFALL DISTRIBUTION ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP(INCHES) 25, 24, 3.9 ******************** S.C.S. TYPE-1A DISTRIBUTION ******************** ********* 25-YEAR 24-HOUR STORM **** 3.90" TOTAL PRECIP. ********* ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1 0, 90, 0, 14, 98, 5 DATA PRINT-OUT: AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) A CN A CN . 1 .0 90.0 . 14 98.0 5.0 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) . 14 7.67 1862 ENTER [d: ] [path] filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH: 25dev SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP n STORM OPTIONS: 1 - S.C.S. TYPE-1A 2 - 7-DAY DESIGN STORM 3 - STORM DATA FILE SPECIFY STORM OPTION: 1 S.C.S. TYPE-1A RAINFALL DISTRIBUTION ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP(INCHES) 100, 24, 4 .5 ******************** S.C.S. TYPE-1A DISTRIBUTION ******************** ********* 100-YEAR 24-HOUR STORM **** 4.50" TOTAL PRECIP. ********* ENTER: A(PERV) , CN (PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1 0, 90, 0. 14, 98, 5 DATA PRINT-OUT: AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) A CN A CN . 1 .0 90.0 .1 98 .0 5. 0 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) . 17 7 .67 2166 ENTER Ed: ] [path] filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH: 100dev