ARCHIVED REPORTS_1993 - Laserfiche WebLink

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DRAINAGE ANALYSIS TRACY MATERIALS RECOVERY AND TRANSFER FACELXrY DRAINAGE CONTROL FACILITIES A surface water hydrology analysis was conducted for the Tracy Materials Recovery and Transfer Facility in order to develop a layout and determine capacities for the storm drainage facilities. The facilities were sized for peak flows resulting from specified 24-hour frequency precipitation events. The surface water hydrology study was conducted using both the Rational Method and computer modeling using the Haestad Methods program FLOWMASTER I. Hydrology calculations are presented in this report. A summary of the design methodologies is presented below. WEMODOLOGY Drainage Scheme Storm water runoff was estimated by dividing the site into numerically designated watersheds as illustrated in Figure E-1. The drainage for the approximately 40-acre site will convey all storm drainage to the retention basin in the northwestern section of the site. Figure E-2 illustrates the conceptual layout for the drainage scheme. Drainage facilities will carry surface flows from the site through v-ditches, curb inlets, and side opening culverts to the retention basin. Runoff from watersheds 1 through 6 will converge at the bottom of the access road, south of the gatehouse at point of concentration (POC) number 14A, and flow west, collecting runoff from watershed 7. This runoff is joined by runoff from watershed 8 through 10 and 19 at POC 15. Runoff from watersheds 16 and 17 will flow south to POC 10, and then west, collecting runoff from watersheds 18 and 12 and converging with runoff from watersheds 1 through 10 and 19 at POC 16. This runoff will then be joined by runoff from watershed 13 before being discharged into the retention basin. Runoff from watershed 14 will flow directly into the retention basin. L:\f%0JECM9MRAW.= December 1993 E-1