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<br />runoff from a standard project flood in the Bijou Creek basin. The <br />dead and inactive storage zones of the Narrows Reservoir"would be, <br />however, inadequate to store the combined sediment runoff from <br />the South Platte River and Bijou Creek over the 100-year life of <br />the project. Diversion of Bijou Creek flows into the Narrows <br />would require an additional 100,000 acre-feet of sediment storage <br />in the Narrows Reservoir. Of this arnQunt, it is estimated that <br />about -IlLQQ~ acre-feet would be deposited in the conservatiDn <br />storage zone. Using the values for conservation storage credited <br />to the llarrows Reservoir, the net benefits for the diversion were <br />estimated by subtracting the losses due to storage depletion <br />from the flood control benefits. The net benefits used in this <br />analysis do not take into consideration the possible losses to <br />general and fish and wildlife recreation. Figure shows <br />estimated benefits and costs for various levels of diversion <br />using 3.250, 5.375, and 7 percent interest rates and 100-year <br />periods of analysis. <br /> <br />h. The optimization studies for the diversion indicated that <br />usinr, a 3.250 interest rate, maximum net benefits over costs <br />would occur for a channel capable of diverting ~ of the standard <br />uroject flood discharge. Using 5.375 and 7 percent rates, maximum <br />net benefits over costs would occur for channels capable of diverting <br />l4% and 1-2% of the standard project flood, respectively. <br /> <br />20. FUll FOR1lULATIOII <br /> <br />a. General. Based on the foregoing analyses, it is apparent <br />that, of all of the alternatives considered, diversion of Bijou <br />Creek flows into the Narrows Reservoir would provide the maximum <br />net benefits over costs. The economic analyses of alternatives <br />also indicated that both diversion and reservoir storage in the <br />nijou Creek basin would be economically feasible if the Narrows <br />Project were operating. Although economic efficiency has been the <br />basic criterion for plan selection, other factors must be given <br />full consideration before selecting a plan from the alternatives. <br />Other factors influencing plan selection, both beneficial ana <br />detrimental, are discussed in the following paragraphs. <br /> <br />b. Diversi~n. Diversion of Bijou Creek flows into the <br />~~rows Reservoir would provide a substantial reduction in flood <br />damages along the lower South Platte River resulting from runoff <br />in the Bijou Creek basin. Sediment from the Rijou Creek basin 'TOuld <br />reduce' the conservation stora~e zone in the Narrows Reservoir. The <br />additional sediment could affect the quality of the recreational <br />opportunities in the Narrows Reservoir. Diversion of Bijou Creek <br />flows would virtually eliminate future opportunities for the <br /> <br />28 <br /> <br />3102 <br />