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29 <br /> Peak Flow Attenuation <br /> Results from the pre-/post-development calculations are a bit more mixed, since the site is actually a <br /> protion of a much larger drainage basin. When reviewed on its own, runoff in the 1-year storm event <br /> increases beyond the 10% allowable. However, when reviewed as a portion of the greater basin, the <br /> increase is only 6% and does not appear to warrant peak flow attenuation. Additionally, it should be noted <br /> that post-development discharges are likely to be reduced further due to the addition of treatment devices <br /> along the drainage path necessary for nutrient removal. <br /> If Orange County Erosion Control does warrant that further peak flow attenuation is required, design and <br /> placement of these items should be heavily coordinated with Orange County Erosion Control to prevent <br /> removal of mature trees as noted above. <br /> CONCLUSION: <br /> Based on the above results, the proposed development appears to be able to meet stormwater <br /> management requirements with minimal issues. However, it is heavily recommended that all work <br /> associated with stormwater treatment and peak-flow attenuation be heavily coordinated with Orange <br /> County Erosion Control. <br /> ATTACHMENTS: <br /> Exhibits <br /> Orange Co. Soils Map Site location highlighted <br /> USGS 7.5 Minute Quad Map Site location highlighted <br /> FEMA Map download Site location highlighted <br /> Stormwater Management Calculations <br /> General Information <br /> Area Breakdown EXCEL worksheet <br /> Drainage Basin Breakdown EXCEL worksheet <br /> Flow Paths EXCEL Worksheet <br /> Peak Flow Attenuation <br /> Drainage Exhibits ACAD exhibits for Pre and Post Development <br /> Hydrographs Hydraflow Worksheets <br /> Preliminary Treatment Lake Jordan Accounting Tool Worksheets <br />