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<br />22 Chapter 4-Present and Future Devalopment
<br />
<br />31,000 acre-feet; Hammond Project irrigation,
<br />10,000 acre-feet; and Four Corners Powerplant,
<br />15,000 acre-feet,
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<br />Miscellaneous Additional Depletions
<br />
<br />These are depletions that have come into being
<br />since the Comprehensive Framework Study
<br />estimates were prepared, These include
<br />5,000 acre-feet of private rights developed for
<br />municipal and industrial purposes, Values
<br />shown were provided by the New Mexico
<br />Interstate Stream Commission,
<br />
<br />Navajo Reservoir Evaporation
<br />
<br />Reservoir evaporation is based upon a Colorado
<br />River Storage Project study made in 1973,
<br />
<br />Animas-La Plata Project (Colorado-
<br />New Mexico)
<br />
<br />See the discussion of the Animas-La Plata
<br />Project in the Colorado section,
<br />
<br />San Juan-Chama Project
<br />
<br />The San Juan-Chama Project was authorized by
<br />Public Law 87-483, Transbasin diversions
<br />began in 1971, The May 1957 Supplemental
<br />Project Report indicates that diversions are
<br />expected to average about 110,000 acre-feet a
<br />year, although more recent hydrologic studies
<br />performed by the Southwest Regional Office
<br />indicate that the long-term average annual yield
<br />may be closer to 104,000 acre-feet, Historical
<br />(1971-83) average diversion has been
<br />99,640 acre-feet a year, For purposes of this
<br />report 110,000 acre-feet have been selected as
<br />the level of existing and future average
<br />depletions,
<br />
<br />Navajo Indian Irrigation Project
<br />
<br />Various estimates for projected agricultural use
<br />depletions have been prepared, including the
<br />studies for the all-sprinkler irrigation system for
<br />the Navajo Indian Irrigation Project (NIIP)
<br />
<br />prepared by the Southwest Region of
<br />Reclamation, This study estimated agricultural
<br />consumptive use of 226,000 acre-feet, Several
<br />other estimates have been made, and a 5-year
<br />field study was made to determine actual
<br />consumptive use on the project, Technical
<br />estimates reported by the Secretary of the
<br />Department of the Interior Report, Economic
<br />Study, May 1980, are 254,000 acre-feet for
<br />agricultural depletions,
<br />
<br />
<br />The State of New Mexico has stated that the
<br />projected depletion estimates for the NIIP under
<br />full project development will not reach
<br />267,000 acre-feet and that a more reasonable
<br />estimate of the maximum project consumptive
<br />use would be 254,000 acre-feet annually, The
<br />267,000 acre-feet depletion value is based on the
<br />full 110,630 acres being irrigated each year,
<br />Based on historical data, at least 5 percent of the
<br />total irrigable acreage has been fallow in any
<br />1 year since 1981.
<br />
<br />In November 1981, it was concluded and agreed
<br />by the Assistant Secretary, V,S, Department of
<br />the Interior, Land and Water Resources, and
<br />Assistant Secretary, V,S, Department of the
<br />Interior, Indian Affairs, that the productive
<br />acreage of the project should be 110,630 acres,
<br />rather than the 105,000 acres which had been
<br />assumed in the past, Correspondingly, the
<br />annual depletion estimate has been revised from
<br />254,000 acre-feet to 267,000 acre-feet,
<br />
<br />The first block ofland (about 9,300 acres) was
<br />irrigated in 1976, In 1985, blocks 1 through 5
<br />were in production, and some water had been
<br />delivered to block 6, Although some return flow
<br />from the project has been observed, the
<br />depletion of river flow is very nearly equal to the
<br />water diverted from Navajo Reservoir, Return
<br />flow to the river will increase as deep percolation
<br />from irrigation charges the aquifer,
<br />
<br />Hammond Project
<br />
<br />In 1987, the Hammond Project delivered
<br />14,850 acre-feet of water to irrigate 2,972 acres
<br />offarmland at an average of 5,0 acre-feet per
<br />acre, The project depletes 10,000 acre-feet per
<br />year if all of the project lands (3,930 acres) are
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