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HomeMy WebLinkAboutDrainage Study For tact 6557-addendum 2Tract 6557 Phase 2 City of Bakersfield Summary of Storm Drain changes Prepared for: City of Bakersfield Prepared by: Preston Brittian Catch Basins #17 and #18 were removed. Catch Basins #16 and #19 will collect the drainage from the removed boxes. Hydraulic calcs were checked, and the flows an hydraulic grade lines are all within allowables. Preston Brittian Stantec Consulting Ltd. October 29, 2015 Width (ft)Cross Slope (ft/ft)Long. Slope (ft/ft)Manning's coeff. (n)Flow depth (ft)Calculated Used 16 1.21 Curb Inlet Sag 2 0.0833 -0.015 0.27 2 3.75 4.0 19 1.35 Curb Inlet Sag 2 0.0833 -0.015 0.30 2 3.54 4.0 20 1.80 Curb Inlet Sag 2 0.0833 -0.015 0.34 2 3.98 4.0 The curb inlet lengths are calculated using the formulae below. For more detailed information refer to Section 3.1.1 Inlets on grade: Inlets at sag: The computations are per Federal Highway Administration "Urban Drainage Design Manual", sections 4.4.4.2 and 4.4.5.2 Curb Inlet Length (ft) CURB INLET OPENING LENGTH CALCULATIONS Inlet Condition Inlet Depression (in) GutterINLET ID Known discharge (cfs)Junction Type 6.03.042.0 )1( e LuT SnSQKL×= 5.1)8.1(dWLCQwi+= TABLE 2.1.1-B Column 1 Column 2 Column 4 Column 6 Column 7 Column 8 Column 9 Column 10 Column 11 Column 13 Column 14 WATERSHED AREA (ac)LENGTH (ft)EL. DIFF. (ft)Roof to Gutter Travel time Total Time 16 & 17 2.46 282 1.0 0.004 CB16 0.000 0.16 0.1602 1.081 0.39 15 4 19 1.27 1.212 18 & 19 3.27 650 2.2 0.003 CB19 0.000 0.30 0.9118 1.391 0.38 15 8 23 1.10 1.349 DISCHARGE D.S. (cfs) DISCHARGE U.S. (cfs) Tract 6557 10-yr 24-hour Peak Flow Analysis Column 3 Column 5 Column 12 Time of Concentration (min)SLOPE Street Flow Water Depth (ft) Average Flow VelocityAREA #UPSTREAM AREA DOWNSTREAM AREA WATERCOURSE Flow Area (ft2)10-yr 24-hour Rainfall Intensity (in/hr) Runoff Coefficient ( C )