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9�i1a9&yIll I:VlLlFil &II-VlLl10LViIIll I[Hil9Eel Lll <br />This residential development is expected to add an assumed 29,679 sf for future <br />private road, driveways and roofs. However, the effective impervious surfaces for this <br />project total less than 10,000 sf (see section 7 and 9 of this report). <br />The runoff from the new private road and the roof surfaces on lot 3 will be directed to <br />individual bioretention cells, and all of the individual driveways will be constructed of <br />permeable pavement. Roof runoff from lots 1, 2, 4, 5 and 6 will be collected and <br />tightlined to the existing stormwater conveyance system within the Holly Drive right of <br />way due to lack of available space for infiltration. <br />A. UPSTREAM ANALYSIS <br />There are no significant off -site areas that drain toward the proposed project area. All <br />off -site flows will pass through or around this site and remain that way during <br />construction. Based on the location of the proposed improvements the existing runoff <br />from the upstream area will continue to flow unaffected around this site after the <br />project has been constructed. <br />B. DOWNSTREAM ANALYSIS <br />Runoff from the proposed disturbance area of the existing site sheet flows in a <br />generally southern direction and flows through a culvert near the southeastern <br />property line and into a catch basin within Holly Drive right of way. Runoff in this <br />stormwater conveyance main runs southwest down Holly Drive approximately 750 <br />feet, at which point the downstream analysis was concluded. <br />See Figure 4 for Downstream Basin. <br />Perez SP <br />March 2022 <br />Revised: June/August 2022 Page 6 <br />