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Acre Short Plat Stormwater Site Plan <br /> The land use areas displayed in Table 8.2 were used for the WWHM analysis. <br /> Table 8.2 -- WWHM Input <br /> .WWHM Input <br /> Area <br /> 5F Acre". <br /> Pre-Developed* 29,590 0.679 <br /> C, Forest,Steep 29,590 0.679 <br /> Developed 29,590 0.679 <br /> C, Forest, Steep 6,679 0.153 <br /> C, Lawn, Mod 14,625 0.335 <br /> Roof Tops Flat 4,660 0.107 <br /> Driveways, Steep 3,106 0.071 <br /> Bypass 520 0.012 <br /> *Pre-developed area includes total on-site area and off-site driveway areas. <br /> Input and output parameters for the WWHM model are provided in Appendix C of this report. <br /> The developed conditions of the site were modeled using WWHM to complete a flow control analysis of <br /> the project.All of the new homes and the majority of the on-site paved surfaces will be collected and <br /> conveyed to the on-site detention tank system. Due to the steepness of the site and proposed driveway <br /> grades, a portion of the driveways for Lots #2 and #3 cannot be conveyed to the detention system. These <br /> areas were modeled as bypass areas in the WWHM analysis as shown in Table 8.2. <br /> An on-site detention tank is currently proposed to provide flow control for onsite stormwater runoff <br /> discharge. A summary of the detention tank is provided in Table 8.3 and more detailed results are provided <br /> in Appendix C with the WWHM results. <br /> Table 8.3 —Detention Tank Summary <br /> Detention Tank" <br /> Length 110' <br /> Tank Diameter 6' <br /> Riser Height 5.5' <br /> Riser Diameter 18" <br /> Orifice 1 Diam., Elev. 0.61", 0' <br /> Orifice 2 Diam., Elev. 3/411, 3' <br /> Orifice 3 Diam., Elev. 9/16', 4' <br /> Due to the existing topography and roadway grades, a portion of the driveways for Lots #2 and #3 and <br /> Crescent frontage improvements will bypass the proposed detention facility. <br /> D. Stormwater Flow Control Plan <br /> The release from the detention vault will be controlled by a standard flow control structure designed to <br /> control the peak runoff rates and durations of storm runoff from the site in accordance with City surface water <br /> design standards. The controlled release from the tank system discharges to the combined sewer system <br /> located in Crescent Avenue. <br /> October 15, 2021 <br /> Page 18 <br />