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<br />PURGA'l'OIllE (PICKET WIRE) RIVER, COLO.
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<br />, 68. Studies by the United States Department of the Interior, Bureau
<br />of Reclamation, indicated that for a flood detention capacity of 5,200
<br />acre,feet, an additional 5,540 acre,feet of water would be available to
<br />irrigators annually. ' '
<br />69. The structure for plan 1 would provide a concreteoverJlow
<br />section, concrete bulkhead sections, and an earth embanknient sec,-',
<br />tion. The over,alllength of the structure would be 2,545 feet and'the'
<br />top of the dam would be at elevation 6,262, which is 107 feet above
<br />the clevation ,of the stream bed. The concrete spillway section
<br />would be 398 feet in length with the crest at elevation 6,235, which is
<br />approximately 100 feet above the elevation of bedrock. The spillway
<br />would be:controlled by seven 22, by 50-foot 'I'ainter gates to maximum
<br />pool' elevation at 6i257. Two concrete bulkhead sections, one 265
<br />feet in length wou d concatenate the spillway with the left bank
<br />abutm<lJJlt" the ,other 258 feet in length would key the' embankment
<br />section. ' The embankment section would be a pervious rolled fill
<br />with 3 on 1 slopes with a riprapped blanket on the upstream face
<br />and a graded gravel blanket on the doWnstream face, An impervious
<br />core extending 'up to elevation 6,170 would key the pervious section
<br />to bedrock. Five outlets, bne \lngated and four gated, would be
<br />provided, State Highway 12 would be relocated for approximately
<br />1 mile. The Colorado & Wyoming Railway would be relocated for a
<br />distance of 2.16 miles. This relocation would require 'a tunnel
<br />through the embankment section of the dam, Utilities and a ceme-
<br />tery would also have to be relocated.
<br />70. The estimated first costs were $3,641,100 and the average
<br />annual'<i!iarges \yere$176,000 for this structure. ,
<br />71. Investigations to determine the dual,purpose reservoir which
<br />would provide the greatest ratio of benefits to cost, indicated that a
<br />concrete overflow, section and concrete bulkheads with the spillway
<br />crest at elevation 6,195 would meet these criteria.
<br />72. Studies of rUll'01l', during the period of record from 1922
<br />through 1941, indicated that for a flood detention capacity of 3,180
<br />acre-feet all additional 5,200 acre,feet of water would be available to
<br />irrigators annually.
<br />, 73. 'rhe structure for phin 2 would provide a 1,000,foot overflow
<br />section with a spillway crest at elevation 6,195, fl8Jlked by 2 bulkhead
<br />seotions 1.60 and 190 feet in length. The over,all length would be
<br />1;350'feiJt; , 'rhetci> of the dam would be at elevation 6,210, which
<br />is about 55 foot above stream bed elevation and 75 feet above bedrock.
<br />Discharge would be uncontrolled by one outlet to the crcst elevation
<br />6,195. State Highway 12 would be relocatcd for approximately 0.73
<br />mile. The Colomdo & Wyoming Railway would be relocated for a
<br />distance of 1.44 milcs, Utilities would .1so be relocated.
<br />74, The estimatod first costs of the structure were $1,174,800 and
<br />the annual charges $61,600.
<br />75. Details for thcse structures arc given in appendix D.'
<br />76. Sopris ReBe,'voir for flood control only,-,-No detailed illvestiga,'
<br />tions were made for tIllS structure, as it was obvious from the inves,
<br />tigations of the dual'purpose structures that the project could not be
<br />justified at this time. '(See projectjustiiication, pal'. 92,)
<br />77. Sopris Reservoir for flood control and irrigation~Glw"nel im-
<br />provement through Trinidad jar flood cont1oi,-It is apparent from the
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<br />1 Not printed.
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