Laserfiche WebLink
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 />We 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 alternates varies significantly. <br />Alternate I would provide an eight inch outlet pipe with approximately 0.5 <br />acre-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 />acre-feet of storage required in a major storm. This would bring the water <br />elevationi to a point 0.5 feet below the garage floor at 3055 Casco Point <br />Road. The construction 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 />01391119 <br />