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<br />e <br /> <br />Alternatives 2 and 3, but especially the third alternative, could utilize the proposed <br />diversion of flood flow through the L- W Canal to the Cache la Poudre River. The <br />diversion could be accomplished via a newly constructed flood control channel as an <br />extension of the existing canal and then terminating at existing Dry Creek. This new <br />extension diversion canal is referred to as the East Vine Diversion Canal. <br /> <br />Alternative No.3, Temporary Storage and Diversion, was determined to be the only <br />feasible alternative. In an attempt to optimize Alternative 3, and respond to property <br />owner concerns, four options were developed and analyzed. The four options were <br />developed after public meetings, intensive hydraulic analysis, and topographic review. <br />The four options consist of different configurations of detention storage facilities with a <br />common diversion element and certain common storage elements. The four options are: <br /> <br />· Option A) Existing detention, common features, and one 540 acre-feet of new <br />detention on the City of Thornton Property (COTP) plus seven smaller detention <br />facilities, see Figure ES-Al. <br /> <br />· Option B) Existing detention, common features, and one 720 acre-feet of new <br />detention at Dam #5 and #6 site, see Figure ES-B 1. <br /> <br />e <br /> <br />· Option C) Existing detention, common features, and one 320 acre-feet of new <br />detention on the COTP and a 220 acre-feet of new detention at Dam #6 site, see <br />Figure ES-Cl. <br /> <br />· Option D) Existing detention, common features, and one 540 acre-feet of new <br />detention on COTP and a new 2l0-acre feet of new detention at the Happy Cow <br />site, see Figure ES-Dl. <br /> <br />The facilities contemplated for construction as part of the Dry Creek Flood Control Project <br />may lend themselves to phased construction. The proposed phasing schedule is outlined in <br />detail later in the report. <br /> <br />e <br /> <br />Benefits generated by implementing the selected alternative include: the removal of 800 <br />structures from the 100-year flood plain; increased development potential in the lower <br />basin; improved capacity of the L- W Canal; needed flood protection in the Middle Basin; <br />and increased land values throughout the two basins. The recommended project also <br />eliminates the direct damage from the 100-year flood event that is estimated at $15 million <br />and expected to further increase. A flood of this magnitude could also result in loss of life, <br />which is not measurable in dollar terms. Damages from lesser, but more frequent, 50 year <br />floods and 10 year floods would also be avoided through development of the <br />recommended project. The estimated benefit of avoided flood damages, over a fifty year <br />project life, is approximately $42 million in year 2001 dollars. To the damage avoidance <br />benefit the Company estimates the value of improvement in water handling due to the <br />pipeline would be $5 million over the fifty year project life, which brings the total benefit <br />to $47 million. The estimated benefit to cost ratio, including other capital projects <br />anticipated by the utility, is 2.35. <br /> <br />.I <br /> <br />Final Feasibility Study for the Dry Creek Basin <br /> <br />7 <br />