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K <br />f-*r- <br />DISCUSSION <br />The drainage area for this watershed is approximately 3.25 acres as shown <br />on Figure 1. The topography is rolling and high rates of runoff would be <br />expected. There is some temporary ponding available if the backyard areas are <br />flooded. <br />Ve reviewed three alternates for providing the storm water outlet <br />capacity. Alternate I would be to design for maximum storage with minimum <br />outlet capacity. Alternate II would be to design for a safe amount of storage <br />with a modest outlet capacity. Alternate III would be to provide for minimal <br />storage and a maximum outlet capacity. The environmental Impact for each of <br />the altenu :ies significantly <br />Alternate 1 would provide an eight inch outlet pipe with approximately O.S <br />*cre-feet of storage required in a major storm. This could bring the water <br />elevation above the garage floor at 3055 Casco Point Road. The construction <br />of an overflow drainageway would be necessary with this alternate. <br />Alternate II would provide a ten inch outlet pipe with approximately 0.35 <br />ocre-feet oV storage required in a major storm. This would bring the water <br />elevation to a point 0.5 feet below the garage floor at 3055 Casco Point <br />Road. The r.onstructlon of an overflow drainageway would be desirable with <br />this alternate. <br />Alternate III would provide an eighteen inch outlet pipe and virtually no <br />storage would be required. The construction of an overflow drainageway would <br />not be necessary with this alternate <br />. 4 . <br />01391179 <br />I <br />% <br />i