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<br />29')"- <br />...J <br /> <br />xiii <br /> <br />to a choice between the Narrows and Fort llorgan sites, vnth comprehensive studies <br />from both engineering and economic aspects being made before Narrows site was <br />finally selected. <br /> <br />Fort Horgan Site .--A comparison of these two si tee SlOWS a differential in con- <br />struction contract costs of over ..2,000,000 in favor of the lJarrol'ls site. FOlll1d- <br />ation studies indicate that losses by seepaGe at the Fort Horgan site would be about <br />twice that at the liarrows site and that fener seefage problems would result from the <br />HarrovlS lteservoir because of its favorable location in relation to the Bijou Creek <br />channel, which would act as a cutoff drain. The averace annual evaporation from a <br />reservoir at the Harrows site would be 6,000 acre-feet less than the evaporation at <br />the Fort Morgan site. Use of the Narrows heservoir Yo\. 11 remove from production by <br />Government acquisition a total of 6,497 acres of irrigated land compared with 5,549 ' <br />acres at the Fort ~~rgan site--a difference of 948 acres. A reservoir at the Fort <br />Worgan site ,nth a capacity of 709,000 acre-feet would approach the physical limits <br />of the site, and there would be no chance for enlargement, if over a period of years <br />the'water supply situation changes or sediment encroaches beyond the capacity al- <br />lotted for this purpose. <br /> <br />The Narrows site was found to be the most economical site available. It allows <br />the creation of the greatest benefits from all aspects; it is the best plan from an <br />engineering standpoint in that seepage problems are less than at other sites; it'has <br />greater flexibility to accommodate changing conditions in that a portion of the sur- <br />charge space provided for protection of the dam against occlrrrence of a spillway <br />design flood could be converted to other uses by installation of auxiliary spillway <br />capacity. <br /> <br />Plan of Developnent <br /> <br />The major feature in the p Ian of development is the ].j?rrows Dam and Ileservoir <br />with a total storage capacity of 700,000 acre-feet, e;:clll5ive of surcharge space. <br />This dam willbe located at the Narrows site on the ~outh ~latte River about 7-1/2 <br />miles wast of Fort I~rgan. To attain maximum flood co~trol, it is essential that <br />Bijou Oreek, nhich enters the 00uth ~latte River a short cistance below the Narrows <br />Dam, be controlled. In order that physical conditions at the damsite can be util- <br />ized most advantageously, the recommended plan cal~s for a ~ominal capacity spill- <br />way to protect the dam, with the main protection for the structure agaj.nst the spill- <br />way design flood being provided through use of 318,000 acre-feet of surcharge space. <br />The plan provides considerable flexibility for adaptation to any fdure needs. It <br />will be possible to increase the spillvlay capacity; thereby converting a portion of <br />the surcharge space to other uses. Developnent of power at the ~arrons site has been <br />considered, but under existing economic conditions is not feasible. ~rovision has <br />been included in the reconunended plan for future poV/er instalJa tion since power <br />development may become feasible at some future date. <br /> <br />Narrows dam will consist of the main structure across the ::iouth ?latte River <br />and dikes across low spots between warrows Dam and Bijou Creek, 3ijou Creek will be <br />diverted into Narrows lieservoir by means of a dike across this strea.'ll and a channel <br />between Bijou Creek and the ::;outh Platte River to connect the two drainages into one <br />Teservoir area. A pilot channel, 3.9 miles long, will extend from Bijou Creek <br />