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<br />Chapter V - Evaluation of Alternatives <br /> <br />A. Plan A - No Action <br />Inquiry was made to the State Engineer's Office to determine what action would be taken <br />if the Company did nothing to increase the spillway capacity at Left Hand Valley Reservoir. The <br />Dam Safety Branch responded that storage would have to be restricted to the level at which the <br />reservoir could store and pass the 75 percent PMP design flood through the existing spillway <br />without overtopping the dams. Analyses using HEC-I were made with various starting reservoir <br />contents to find the storage level at which the flood could be safely routed through the reservoir. <br />The analyses showed that even if the reservoir was at the dead storage level at the start of the flood_ <br />the dams would be overtopped by about one foot. Therefore, the SEO could order that the north <br />dam be breached, causing complete loss of the reservoir as a storage facility. A complete breach <br />would involve the removal of approximately 32,000 cubic yards of material at a cost of <br />approximately $64,000-$96,000. The loss of the value of the storage facility (assuming a <br />replacement value of $4,000 per acre-foot) would be about $6,400,000. Because of the possible <br />complete loss of the reservoir Plan A is not considered to be feasible. <br /> <br />B. Plan B - Widening the Existing Spillway <br /> <br /> <br />As mentioned previously, the existing spillway is an excavation through the rock knob which <br /> <br /> <br />forms the south abutment of the north dam. Because it is located between the two dams the knob <br /> <br /> <br />also forms the north abutment of the south dam. The knob is located immediately west of the main <br /> <br /> <br />road into the nearby residential subdivision and golf course and features very prominently in the <br /> <br /> <br />local vistas. Excavation through the knob wOll1d drastically affect the view, replacing the natural <br /> <br /> <br />contours with a dramatic cut at the crest of the spillway and the artificial contours of the chute down <br /> <br /> <br />the side of the hill. When contacted, the Lake Valley Homeowners Association officers confirmed <br /> <br /> <br />their concern over the appearance the spillway enlargement project. <br /> <br />25 <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />, <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />r <br />" <br />