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The following summarizes the calculations for the peak runoff rates from the developed <br /> portion of the site: <br /> The input for the WWHM existing condition is as follows: <br /> Roof Tops Flat: 0.07 acres <br /> Driveways, Flat: 0.33 acres <br /> Developed conditions: <br /> Roof Tops, Flat: 0.23 acres <br /> Driveways, Flat: 0.17 acres <br /> Peak 100-year flow rate for Existing Condition: 0.43 cfs <br /> Peak 100-year flow rate for Developed Condition: 0.43 cfs <br /> Change in 100-year flow rate: 0.00 cfs <br /> The site has been analyzed for the existing conditions and developed conditions to <br /> determine the increase for the 100-year peak runoff rate of 0.00 cfs. This result was <br /> expected when the use of the flow reduction credits was applied to the model. Therefore, <br /> runoff quantity control falls within the 0.15 cfs (15-minute time steps) increase in the 100- <br /> year peak flow rates for the existing and developed conditions. <br /> 10. SUMMARY <br /> This project proposes to construct more than 5,000 sf of new plus replaced impervious <br /> surfaces. However, the existing site is currently developed and consists of mostly <br /> impervious surfaces, therefore the net new impervious surfaces only totals approximately <br /> 212 sf. Thus, the use and land cover for less than 5,000 sf of the site will be converted <br /> from pervious to impervious surfaces. Based on the proposed improvements for the site <br /> drainage design the post developed runoff from the site is expected to be slightly greater <br /> than the existing system. <br /> McDougall Warehouse 17-0212 <br /> April 2017 Page 10 <br />