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<br />OilnJ89
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<br />14 WATER SUPPLY FORTHESAN~.JU:AN~CHA1\lA PROJECT
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<br />the bypass demand would amount to an average of 10,000 acre-feet
<br />a year with a maximum yearly demand of 33,000 acre-feet. .
<br />If the basic assumptions are modified by assuming that 50 percent
<br />of the 224,000 acre-feet per year M. & L demand is available as return
<br />flow for meeting channel losses and prior rights the bypass demand
<br />would amount to an average of 5,000 acre-feet a year.
<br />If the above two modifications of the basic assumptions are com-
<br />bined, the bypass' demand of prior rights would average only 900
<br />acre-feet per year.
<br />
<br />Comments and conclusions-Physical operations
<br />In my analysis and study I found no material discrepancies with
<br />respect to the physical data for the San Juan Basin, The various
<br />Navajo Reservoir operation studies differed with respect to the
<br />historic periods covered by the studies and with respect to the assump-
<br />tions upon which they were based, The conclusions of the various
<br />studies are compatible, In addition to the studies that have been
<br />discussed, I bave analyzed and given consideration to the testimony
<br />of Mr, Utton in behalf of the San Juan County Farm and Livestock
<br />Bureau. Mr. Utton's conclusions with respect to water supply are
<br />based upon flows during the last 10 years,
<br />With respect to the historic period of coverage, the Bureau of
<br />Reclamation used the 33-year period, 1928-60; the New Mexico
<br />study by Mr. Reynolds covered the period 1928-59; the Upper Colo-
<br />rado River Commission study and the Jex study used the most critical
<br />streamflow period of rec()rd; 1942-56; and the Colorado Water Conser-
<br />vation Board study, referred to as Study A-I, covered the period
<br />1943-56.
<br />First, I will discuss the depletions of the San Juan River upstream
<br />from the Navajo Reservoir. The Bureau made an allowance for the
<br />authorized but unconstructed Pine River extension andWeminuche
<br />Pass projects in addition to present uses, and the Bureau's study
<br />indicated an average annual depleted flow at Blanco of 899,700 acre-
<br />feet which is essentially a measure of inflow to Navajo Reservoir not
<br />including bypass requirements. The New :MeAico study by Mr.
<br />Reynolds and the Upper Colorado River Commission study made the
<br />same allowance for upstream development as the Bureau. Mr,
<br />Reynold's study showed average annual residual flow at Blanco of
<br />901,100 acre-feet, but the commission study, because of the critical
<br />period used, showed inflow to Navajo Reservoir averaging only 757,700
<br />acre-feet. The Jex study, which gives estimates of ultimate upstream
<br />development, indicates ultimate depletions above Navajo Reservoir
<br />totaling 123,400 acre-feet annually of which future stream depletions
<br />amount to only 44,500 acre-feet. In other words, the Jex study, as
<br />I interpret it, indicates the need for less water above Navajo Reservoir
<br />than the amounts assumed by the Bureau, New Mexico, and the
<br />Upper Colorado River Commission. The Pine River extension project
<br />and the Weminuche Pass diversion are presently considered infeasible.
<br />However, they could be determined feasible some time in the future
<br />under different economic conditions and even if they are not developed
<br />as presently planned there will undoubtedly be opportunity to use
<br />this water in the State ,of Colorado. Therefore, I believe that, for
<br />planning purposes, the allowance made for future upstream depletions
<br />by the Bureau, New Mexico, and the commission should be adhered to.
<br />
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