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<br />
<br />12 WATER SUPPLY FOR THE SAN JUAN-CHAMA PROJE'CT
<br />
<br />The commission's studies of the annual yield of Navajo Res.ervoir
<br />resulted in a determination that during the most critical streamflow
<br />period of record, 1942-56, the reservoir would yield 756,000 acre-feet
<br />of shortage-free water. Excluding the 4 exceedingly dry years, 1953
<br />through 1956, the annual yield of the river with Navajo Dam and
<br />Reservoir, with infrequent and tolerable shortages, would amount to
<br />approximately 850,000 acre-feet. With committed diversions of
<br />629,500 acre-feet for the initial phase of the San Juan-Chama project,
<br />the Navajo Indian irrigation project and the Hammond irrigation
<br />project, this would mean that for the entire critical period, there
<br />would bean additional 126,500 acre-feet annually available from the
<br />reservoir. Excluding the 4 dry years, the reservoir yield would
<br />furnish about 220,000 acre-feet of water for additional uses.
<br />The commission's study of the Animas-La Plata River indicated
<br />that the average annual remaining flow of the Animas River at Farm-
<br />ington to supply uses below Farmington would be approximately
<br />320,000 acre-feet after the depletions for the Animas-La Plata project
<br />(193,900 acre-feet), the Florida project (13,900 acre-feet), the Farmers
<br />M,utual Ditch (21,200 acre-feet) and Farmington municipal and in-
<br />dustrial supply (10,600 acre-feet). The commission's study concluded
<br />that this remaining flow, when added to the return flows from irriga-
<br />tion and municipal and industrial uses, would be more than enough
<br />to satisfy present and authorized irrigation demands and supply
<br />municipal and industrial uses of at least 50,000 acre-feet annually
<br />and that there is an ample supply of water from the Animas River for
<br />the Animas-La Plata project even under conditions of adverse stream
<br />runoff.
<br />Supporting these conclusions of the commission are operation studies
<br />of the Animas River below Farmington for the critical period 1942 to
<br />1956, with varying demands for irrigation and for municipal and indus-
<br />trial uses. In the studies, the water supply was distributed in .the
<br />. following order: (1) Animas-La Plata project, (2) Florida project,
<br />(3) Farmers Mutual Ditch diversion, (4) Farmington municipal and
<br />industrial uses, (5) Kirtland irrigation demands, (6) future Kirtland
<br />municipal and industrial uses, (7) Hogback irrigation demands. The
<br />purpo~e of the ~tudies was to. show ~he bypass requirement.s from
<br />NavajO ReserVOIr to meet Ammas RIver rIghts below Farmmgton.
<br />The bypass requirements are indicated by shortages in the studies.
<br />In the first study, Kirtland irrigation demands were assumed to be
<br />23,000 acre-feet and Hogback irrigation demands 71,800 acre-feet.
<br />The results showed there were no shortages at Kirtland and average
<br />annual shortages of less than 1 percent at Hogback. In the second
<br />study, Kirtland irrigation de:l1ands were assumed to be 23,000 acre-
<br />feet, Kirtl~n~ m~lllicipal and irrigation demands 40,000 acre"feet, an.d
<br />Hogback IrrIgatIOn demands 71,800 acre-feet. The results of thIS
<br />study indicated no irrigation shortages at Kirtland, municipal and
<br />industrial shortages at Kirtland averaging around 2 percent, and Hog-
<br />back irrigation shortages averaging about 2 percent, In the third
<br />study, an additional 20,000 acre-feet was added to the Kirtland munic-
<br />ipal and industrial demands with the result that the Kirtland M. & 1.
<br />shortages averaged 6 percent while the Hogback irrigation shortages
<br />averaged around 2 percent. In the fourth study, the demands were
<br />kept the same but a reduction of 35 percent was made in the return
<br />flows. This caused shortages in Kirtland irrigation averaging 1 per-
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