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<br />"fl:~'''' n <br />~.; ....1 ",) I.. .....:j <br /> <br />. <br /> <br />Cache 1a. Poudre POIIer Condu.it <br /> <br />A pressure tunne~ 20 feet in diameter and 5,000 feet in ~ength <br />would convey flows rangl.ng up to 3,000 cfs from the forebay (Cache <br />]a Poudre Forebay) to the surge ta.nk for the Cache 1a. Poudre <br />PC'iI"erplAnt. An in~et struct=e and a trash rack would be installed <br />at the in1.et porta~ of the tunne~ foll~red by a gate she.:f't and <br />emergency gates. The forebay and the out~et portal. of the tunneJ. <br />would be connected by a service road. <br /> <br />Cache la Poudre PowerplAnt. Penstock, Surge Tank, <br />and Channel Contro~ Structures <br /> <br />. <br /> <br />The Cache 1a. Poudre powerplAnt would be ~ocated on the north <br />shore of Grey MO\Ultaln Reservoir. The dra1't tubes would be set <br />about 50 feet be~ow the normal water surface of the reservoir to <br />gain additional head when the reservoir is in a drawn down condition. <br />The ple.nt would be used for peaking; the head would vary with the <br />water surface in Grey Mountain Reservoir and in the forebay. <br />Installed capacity of the 4-unit plant would be 250,000 j(W. The <br />ple.nt factor would be about 7.2 percent on an annuaJ. basis and 9.2 <br />percent on a weekly basis assuming 5-1/2 days per week. <br /> <br />A steel surge tank about 48 feet in diameter and 160 feet <br />high would be constructed at the lower end of Cache 1a. Poudre <br />Conduit. Four penstocks originating at the surge tank each 88 <br />inchee in diameter would convey the water 1,500 feet to the power- <br />plant. The design head of the plant would be 1,180 feet and the <br />maximum capacity would be 3,000 cfe. <br /> <br />The following structures, also included in powerplant costs, <br />are designed to permit operation of the powerplant without <br />injurious effects when Grey Mountain Reservoir is at low stages. <br />An overfiow weir would ma.intain a pool for keeping the dra1't tubes <br />submerged at aD. times. Dmmstream from the pool a baffled apron <br />drop extending to the river channel would be prOvided to :prevent <br />erosion. <br /> <br />When the water in Grey Mountain Reservoir is at the top of <br />the dead storage level, the headwaters would be about 1-1/2 miles <br />downstream from the powerplant. To prevent fluctuations in this <br />1-1/2-mile reach of the river, at low water elevations, two concrete <br />ogee-type overflOll dams, each 35 feet in height, would be con- <br />structed to maintain two permanent pools. At times when the water <br />leve~ is rising above the top of the dead storage pool the dams <br />and successively more of the baffled apron drop would be submerged. <br /> <br />. <br /> <br />7 <br />