AZ vs. CA:24 California Exhibits, Vol. XXIV; Miscellaneous

page 43

PROBLEMS OF IMPERIAL VAIiLBY AXtD VICIKITTf. 43 Bluff.-Site would not be satisfactory for irrigation because of large silt discharge compared to size. Furthermore, the-entire flow of the San Juan, except in extremely high floods, can be used for irrigation in the lower basin. The Bluff «ould be used as a detention reservoir. Junction.-Because of lack of foundation. > Bedrock.-Because irrigation above will exhaust the tributary flow. Summing up, the following reservoirs have been found to be suitable: Capacity in acre-feet; Explored: Flaming Gorge-Green..........*......*...........................4,000,000 Juniper-Yampa......................___....................... 1,500,000 Dewey-Grand.....................................___.............2,270,000 The sum total of the known feasible capacity is 7,770,000 acre-feet, but silt storage is required at Dewey to take care of the 10,000 acre-feet passing that site yearly, and if 770,000 acre-feet is reserved for this purpose there remains only 7,000,000 acre-feet* of water capacity. For plan 1, which is only a temporary expedient, any one of these reservoirs would be approximately sufficient. However, the amounts of storage necessary as calculated for that plan should be increased by about 20 per cent to provide for increased difficulty of regulation from a reservoir so distant and to provide for evaporation loss from the reservoir surface, so that if JDewey or Juniper were used, there would be shortage in 1900 and 1902. ," ., - A serious objection to the use of Juniper or Flaming Gorge is the interference with potential power at the sites and below.- ¦ There exists a necessity tor early addition of power development in that vicinity, and the value of the sites would be largely impaired if the flow of those rivers were regulated for irrigation. The potential power on tne Yampa at the present time is 245,000 horsepower and on the Green to the mouth of the Yampa 260,000 horsepower. Reconnaissance has indicated that there are possible sites on the Yampa below Juniper, whereby 73,0 feet of head can be developed and on the Green 800 feet. This objection does not apply to the Dewey, since the flow is large and it is probable that a reservoir for irrigation would so regulate the flow as to make a valuable power site at that point. The conclusion is, therefore, that if a partial development should be found necessary, Dewey reservoir would answer the purpose with material benefit to all interests. For plan 2, about 3,000,000 acre-feet capacity wiiij>rovide the necessary storage except in the low cycle 1902-1904. This capacity exists at Flaming Gorge, but the stream flo;w available, which averages 1,920,000 acre-feet annually now and which estimated irrigation above will reduce to about 1,100,000, makes it useless for so large a storage, except as a holdover reservpir which would retain all the discharge until full and remain full until needed, for a low cycle of years. A plan of operation for a combination oi the three-reservoirs-Dewey, Juniper, and Flaming Gorge-is as follows: Dewey emptied first would provide for 14 years of tne 22 without draft on'