The URL can be used to link to this page

Home My WebLink About6.7-305LAV // Pinnacle Engineering Page 1 Drainage Calculations for Proposed Warehouse Complex 7511 Rosedale Hwy, Bakersfield CA April 28th, 2021 These calculations have been prepared for a proposed warehouse complex, including the road widening of Rosedale Highway, sometimes referred to hereafter as the “Project”. The project proposes several improvements to contain and capture the majority of runoff generated “on-site”. Additionally, as a condition of the project, the construction of a right turn lane was required, which necessitated the relocation of the existing catch basin and extension of the existing storm drain pipe. The purpose of these calculations is to verify adequacy of the proposed “on-site” improvement and the existing catch basin and storm drain pipe in Rosedale Highway. The Project is located on Rosedale Highway approximately a third of a mile east of Coffee Avenue in Bakersfield, California. The site address is 7511 Rosedale Hwy; the APN is 368-060- 10. Rosedale Highway Improvements An existing catch basin is a combination type inlet with a width of 3.5 feet and due to the road widening will be relocated in the flowline 13 ft south of its existing location. The original drainage study indicates the sub-area tributary to the catch basin is 1.80 acres. With the road widening, the tributary area expands by 2,945 square feet, increasing the tributary sub-area to 1.87 acres. The original drainage calculations used to size the catch basins in Rosedale Highway presumably used the Kern County Rational Method. Therefore, although the site is within the City’s jurisdiction, the Kern County Rational Method was used to check adequacy for the relocated basin. Table 1 herein shows the runoff flow rate for each storm event year. For each storm event, the same time of concentration (Tc), intensity (I), runoff yield fraction (Y), and loss rate (Fm) were used as in the original report. In order to remain consistent with the original drainage study, the same software was used for the inlet and storm drain pipe calculations: Hydraflow Express LAV // Pinnacle Engineering Page 2 Extension for Autodesk Civil 3D. With the exception of the flow rate, all user inputs are the same as in the original drainage report. The size of the catch basin, 3.5 feet wide, was evaluated with the revised flow rate. The calculations indicate the inlet is adequate to fully capture the 10-year flow from the tributary sub- area, 1.21 cfs. A maximum of 4.03 inches of headwater is necessary for the inlet to fully capture the flow. Additionally, there will be no flow bypass. In addition, the size of the storm drain pipe, 18-inches, was evaluated. The calculations indicate the storm drain pipe is adequate to fully convey the 10-year flow and will flow open. Due to the small increase in flow, the Hydraulic Grade Line was not re-calculated. “On-Site” Improvements The proposed Project is a 5-acre warehouse complex with 7 proposed buildings and an internal road. The project will be phased; the internal road, storm drain improvements, and a single 14,00 square foot building will be constructed during the first phase. All other improvements will be constructed during the subsequent phases. The proposed storm drain improvements include concrete vee-gutters, four storm drain inlets, and RCP or PVC pipes, which route storm water to the terminal sump at the southwest corner of the property. The terminal drainage sump volume has been sized as per the City of Bakersfield Standards, which is described below. Table 2 herein shows the runoff volume generated for the entirety of “on-site”, including future construction. The calculations are based on the equation provided in the City of Bakersfield Standards. A run-off coefficient of 0.8 was based on Sheet D-2 of the City of Bakersfield Standards. The calculations indicate the 100 year-24 hour storm event generates 0.60 acre-feet of runoff. Table 3 herein shows the capacity of the proposed retention basin. Based on the City of Bakersfield Standards, the retention basin has a water depth of 6.25 feet with 1.25-foot of LAV // Pinnacle Engineering Page 3 freeboard. The retention basin capacity, with the required freeboard, is calculated as 0.61 acre- feet, which is adequate to contain the 0.60 acre-feet of runoff generated “on-site”. Table 4 herein shows the drainage areas tributary to each drainage inlet for the Project. Exhibit A herein shows the drainage areas overlaid on the site plan. All calculations were performed using the City of Bakersfield Standards. Per the city’s standards, a 10-minute time of concentration was used for all areas. The largest flow rate generated “on-site” is 2.17 cubic feet per second (cfs) and 2.54 cfs for the 10-year and 100-year storm respectively. Table 5 herein shows the Hydraulic Grade Line calculations for the Project based on the flow rates calculated in Table 4. A HGL diagram has been included with Table 5. All calculations were performed in accordance with the City of Bakersfield Standards. Additionally, the flow rates from each sub-area were not routed; instead, the flow rates were added “peak-to-peak”, which yields the most conservative analysis. The calculations demonstrate that there is at least 1- foot of freeboard between the HGL and the gutter elevation at all inlet locations. Table 6 herein shows the inlet capacity calculation. The calculations indicate the drainage inlets with less than 6” of headwater have capacity of up to 4.27 cfs, assuming 50% clogging. Considering the greatest “on-site” flow rate is 2.54 cfs, the inlets are adequate to convey the “on- site” flows. These calculations have shown that the proposed storm drain system is adequate to collect, convey, and dispose of storm water for the proposed warehouse complex and expansion of Rosedale Highway. Furthermore, all calculations for Rosedale Highway are consistent with the methods used in the original drainage study. Therefore, the calculations included in this report can be considered supplementary with the original drainage study. LAV // Pinnacle Engineering Page 4 Submitted by: ___________________________________________________________________ Matthew K. VoVilla, R.C.E. 43130 Date 22 04/28/2021 MATTHEW K. VOVILLARCE 43130 EXP. 3/31/20JOB No.:CHECKED BY:DRAWN BY:OFSHEETDATE:DWG NO.:SHEETSLAV// Pinnacle Engineering 12418 Rosedale Hwy., Suite A, Bakersfield, CA 93312 Phone: (661) 869-0184 Fax: (661) 885-4155 ENGINEERING ●PLANNING ●SURVEYING EXHIBIT "A" - AERIAL MAP BUSINESS WAREHOUSE COMPLEX 7511 ROSEDALE HIGHWAY BAKERSFIELD, CA19-878EXHIBIT11/24/20BMBMKV11EXHIBIT "A" - AERIAL MAPSTOCKDALE HIGHWAYCOFFEE RD FRUITVALE AVE COFFEE RDSTOCKDALE HIGHWAY EXHIBIT "B" - FEMA MAPMATTHEW K. VOVILLARCE 43130 EXP. 3/31/20JOB No.:CHECKED BY:DRAWN BY:OFSHEETDATE:DWG NO.:SHEETSLAV// Pinnacle Engineering 12418 Rosedale Hwy., Suite A, Bakersfield, CA 93312 Phone: (661) 869-0184 Fax: (661) 885-4155 ENGINEERING ●PLANNING ●SURVEYING EXHIBIT "B" - FEMA MAP BUSINESS WAREHOUSE COMPLEX 7511 ROSEDALE HIGHWAY BAKERSFIELD, CA19-878EXHIBIT11/24/20BMBMKV11 EXHIBIT "C" - USGS MAPMATTHEW K. VOVILLARCE 43130 EXP. 3/31/20JOB No.:CHECKED BY:DRAWN BY:OFSHEETDATE:DWG NO.:SHEETSLAV// Pinnacle Engineering 12418 Rosedale Hwy., Suite A, Bakersfield, CA 93312 Phone: (661) 869-0184 Fax: (661) 885-4155 ENGINEERING ●PLANNING ●SURVEYING EXHIBIT "C" - USGS MAP BUSINESS WAREHOUSE COMPLEX 7511 ROSEDALE HIGHWAY BAKERSFIELD, CA19-878EXHIBIT11/24/20BMBMKV11 EV EV EV EV EV EV EV EV EV EV EV EV MATTHEW K. VOVILLARCE 43130 EXP. 3/31/20JOB No.:CHECKED BY:DRAWN BY:OFSHEETDATE:DWG NO.:SHEETSLAV// Pinnacle Engineering 12418 Rosedale Hwy., Suite A, Bakersfield, CA 93312 Phone: (661) 869-0184 Fax: (661) 885-4155 ENGINEERING ●PLANNING ●SURVEYING EXHIBIT "D" - DRAINAGE EXHIBIT BUSINESS WAREHOUSE COMPLEX 7511 ROSEDALE HIGHWAY BAKERSFIELD, CA19-878EXHIBIT11/24/20BMBMKV11EXHIBIT "D" - DRAINAGE AREAS Job #: 19-878 Date: 11/3/2020 Created by:BMB Storm Event Year Area (AC)Tc (min)Intensity (In/Hr) Fm Avg (In/Hr)Y Avg (In/Hr)Qmin (cfs)Qcalc (cfs)Qtot (cfs) 5 1.87 26.22 0.68 0.07 0.81 0.93 1.03 1.03 10 1.87 24.91 0.79 0.07 0.81 1.08 1.21 1.21 25 1.87 23.38 0.94 0.07 0.81 1.28 1.46 1.46 50 1.87 22.50 1.06 0.07 0.81 1.45 1.67 1.67 100 1.87 21.85 1.19 0.07 0.81 1.62 1.88 1.88 Flow Rate for Warehouse Complex Frontage 7511 Rosedale Hwy, Bakersfield Table 1 LAV//Pinnacle Engineering Inlet Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Wednesday, Apr 8 2020 Sizing Proposed CB 44 Combination Inlet Location = Sag Curb Length (ft)= 3.50 Throat Height (in)= 1.50 Grate Area (sqft)= 0.34 Grate Width (ft)= 2.13 Grate Length (ft)= 3.40 Gutter Slope, Sw (ft/ft)= 0.083 Slope, Sx (ft/ft)= 0.020 Local Depr (in)= 2.00 Gutter Width (ft)= 2.00 Gutter Slope (%)= -0- Gutter n-value = -0- Calculations Compute by:Known Q Q (cfs)= 1.21 Highlighted Q Total (cfs)= 1.21 Q Capt (cfs)= 1.21 Q Bypass (cfs)= -0- Depth at Inlet (in)= 4.03 Efficiency (%)= 100 Gutter Spread (ft)= 2.14 Gutter Vel (ft/s)= -0- Bypass Spread (ft)= -0- Bypass Depth (in)= -0- You created this PDF from an application that is not licensed to print to novaPDF printer (http://www.novapdf.com) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Thursday, Apr 29 2021 Rosedale Highway - 18-inch Pipe Sized for 10-Year Storm Circular Diameter (ft) = 1.50 Invert Elev (ft) = 385.20 Slope (%) = 0.21 N-Value = 0.013 Calculations Compute by: Known Q Known Q (cfs) = 1.21 Highlighted Depth (ft) = 0.51 Q (cfs) = 1.210 Area (sqft) = 0.53 Velocity (ft/s) = 2.26 Wetted Perim (ft) = 1.87 Crit Depth, Yc (ft) = 0.41 Top Width (ft) = 1.42 EGL (ft) = 0.59 0 1 2 3 Elev (ft)Section 384.50 385.00 385.50 386.00 386.50 387.00 Reach (ft) Job #: 19-878 Date: 11/3/2020 Created by:BMB Description C Area (acre) Total Runoff Volume (cubic feet) Warehouse Complex 0.80 5.01 0.60 Note: Sump volume calculated using City of Bakersfield Standards: Runoff Volume = 0.15 x C x A, where; C = Run-off coefficient A = Drainage area in acres Volume Required Table 2 Runoff Volume Calculations 7511 Rosedale Hwy, Bakersfield LAV//Pinnacle Engineering Job #: 19-878 Date: 11/3/2020 Created by:BMB Side Slope (H to V):2 1 Freeboard:1 ft Depth-water surface:6.5 ft Depth-total:7.5 ft Area-floor:2,187 sf Area-1/2 water surface:4,032 sf Area-water surface:6,214 sf Volume-provided-trial:26,573 cubic ft Volume-provided-trial:0.61 acre ft Conclusions: Table 3 Required Sump Dimensions 7511 Rosedale Hwy, Bakersfield The volume provided by the dimensions of the sump shown above (0.61 ac ft) is greater than the volume of runoff generated on site (0.60 ac ft). Therefore, the sump is sufficient for storing runoff. LAV//Pinnacle Engineering Job #: 19-878 Date: 11/20/2020 Created by:BMB Drainage Area Runoff Coefficient 10-yr Rainfall Intensity 10 -yr (Inches per Hour) Rainfall Intensity 100 -yr (Inches per Hour) Area (Acres)Flow 10-yr (cfs) Flow 100-yr (cfs) A 0.80 1.80 2.10 1.51 2.17 2.54 B 0.80 1.80 2.10 1.21 1.74 2.03 C 0.80 1.80 2.10 1.55 2.23 2.60 D 0.80 1.80 2.10 0.72 1.04 1.21 Total 4.99 7.19 8.38 Note: Flow calculated using rational method Q = C x i x A where: Q = Flow Rate (Cubic Feet per Second) C = Runoff Coefficient i = Rainfall Intensity for 10-yr and 100-yr Storm (Inches per Hour) A = Runoff Area (Acres) Time of Concentration assumed to be 10 minute for all sub-areas Table 4 Sub-Area Flow Calculations 7511 Rosedale Hwy, Bakersfield LAV //Pinnacle Engineering Project Number:19-878 387.35 ft 0.5 Date:11/20/2020 0.5 Created by:BMB 1.0 Reach Segment Flow (cfs) Length (ft) Pipe Diameter (in) Pipe Slope (%) Sf Pipe Friction Slope (ft/ft) Velocity (ft/sec)KT HLF (ft)HV (ft)HLM (ft)Htotal (ft)Yn HGL Downstream Elevation HGL Upstream Elevation Top of Grate/ Inlet Elevation Freeboard (ft) Pipe 1 6.14 31.2 18 4.00%0.00342 3.47 2.00 0.107 0.187 0.375 0.482 -387.35 387.83 CB 1 387.83 391.76 3.93 Pipe 2 3.97 167.0 18 1.00%0.00143 2.25 0.50 0.239 0.078 0.039 0.278 0.64 387.83 388.24 CB 2 388.24 392.16 3.92 Pipe 3 2.23 170.6 12 1.00%0.00392 2.84 0.50 0.668 0.125 0.063 0.731 0.58 388.24 389.88 CB 3 389.88 391.73 1.85 Pipe 4 1.04 12.6 12 4.00%0.00085 1.32 1.50 0.011 0.027 0.041 0.052 -387.35 387.40 CB 4 387.40 391.48 4.08 Notes: See hand calculations for KT breakdown HLF = Head Loss due to Friction HV = Velocity Head HLM = Head Loss due to Minor Losses Pipes 2 & 3 assumed to flow open Table 5 Hydraulic Grade Line Calculations 7511 Rosedale Hwy, Bakersfield Sump Half Water Surface Elevation Catch Basin/Manhole Bend Outlet KT Values A B LAV //Pinnacle Engineering Job #: 19-878 Date: 11/20/2020 Created by:BMB Inlet Type:Christy U23 Area of Grate Opening "A" (square feet): 3.75 Perimeter Opening of Grate "P" (feet): 8.05 Percent of Inlet Clogged (%): 50.00% Orifice Coefficient: 0.67 Weir Coefficient: 3.00 Head on Grate Inlet (feet):0.50 Q (capacity) cfs (Orifice Equation): 7.13 Q (capacity) cfs (Weir Equation): 4.27 Conclusions: Note: 1. Grate openings collected from Christy Catch Basin Catalog 2. Capacity of inlet is taken as the lesser of Orific or Weir equation. Flow capacity for inlet grates exceeds the maximum "on-site" flow rate (2.54 cfs). Therefore grates are sufficient for taking in runoff. Table 6 Inlet Capacity 7511 Rosedale Hwy, Bakersfield LAV//Pinnacle Engineering