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<br />Navajo Reservoir
<br />(San Juan River)
<br />
<br />
<br />Navajo Dam is a rolled, earlhfill embankmenf.
<br />
<br />Water Year 1984
<br />
<br />The elevation of Navajo Reservoir at the
<br />beginning of water year 1984 was 6,080
<br />feet with 1.618.000 acre.feet of active
<br />storage. This high level of carry.over
<br />storage was 0 result of 0 water year 1983
<br />inflow which was 140 percent of normal. It
<br />was planned that Navajo Reservoir would
<br />fill to near its maximum elevation of 6,085
<br />feet with an average 1984 runoff. A small
<br />amount of reservoir space was reserved to
<br />reduce the risk of using the spillway since
<br />spills cause high levels of nitrification in the
<br />San Juan River which is detrimental to fish.
<br />
<br />The April t~rough .J_uly rU[loff forecast made
<br />on ianuary 6,1984, was 1,100,000 acre.feet
<br />which was 156 percent of normal.
<br />Releases of up to 2,500 cfs were
<br />maintained during January through March
<br />to contain this proiected volume of runoff.
<br />Navajo Reservoir was drawn down to
<br />elevation 6,059 feet by the end of March
<br />1984. However, the AprilS, 1984, forecast
<br />of April through July runoff had declined to
<br />800,CXXJ acre.feet or 113 percent of normal
<br />which permitted releases to be dropped to
<br />near the 1,SOO cfs level. The May 7. 1984,
<br />forecast increased to 121 percent of normal
<br />which forced Navajo Dam releases up to
<br />2,100 cfs during most of May. In early
<br />June releases were dropped to 800 cfs
<br />even though the June 7, 1984, forecast
<br />remained at the 121 percent of normal
<br />level. This was done primarily to force
<br />12
<br />
<br />Navajo Reservoir as full as possible to help
<br />limit lake Powell's rise. Navajo Reservoir
<br />reached a peok elevation of 6,083.4 feet on
<br />July 5, 1984.
<br />
<br />The actual April through July 1984 runoff
<br />volume iota Navajo Reservoir wos 734,000
<br />acre.feet which was 104 percent of
<br />normal. The total water year 1984 inflow
<br />was 1,137,000 acre-feet which was 113
<br />percent of normal. The minimum sustained
<br />release level from Navaio Dam was 1.000
<br />cfs while the maximum release was 2,500
<br />cfs. The peak inflow to Navajo Reservoir
<br />during the 1984 runoff was 9,000 ds on -
<br />May 24, 1984. The spillway at Navajo Dam
<br />was not used.-
<br />
<br />Water Year 1985
<br />
<br />It is projected that Navajo Reservoir will be
<br />drawn down to near ele....ation 6,060 feet by
<br />April 1985 in preparation for an average
<br />spring runoff. Releases were held near the
<br />1,500 cfs level throughout most of the 1984
<br />winter months to accomplish this level of
<br />draw down. Releases will be increased
<br />during the runoff season to about 2,CXX)
<br />ds. An average runoff during water year
<br />1985 is expected to fill Navajo Reservoir.
<br />A reasonable minimum level of inflow
<br />would Cause the minimum releases_ to be
<br />near the 530 cfs level for irrigation
<br />consumptive use and maintenance of fish
<br />and wildlife. A reasonable maximum
<br />inflow would force maximum Navajo
<br />releases to about 2,500 cfs.
<br />
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<br />
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<br />
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<br />
<br />Walenall
<br />
<br />Navalo Active Storage'"
<br />
<br />Chart 4
<br />
<br />Reservoir
<br />
<br />Acre.Feet
<br />
<br />EI. (Ft.)
<br />
<br />608S
<br />5990
<br />
<br />Maximum Storage
<br />Inactive Storage
<br />Surface Area (Full)
<br />Reservoir length
<br />(Full)
<br />
<br />I ,696,400
<br />660,500
<br />15,610 Acres
<br />
<br />33 Miles
<br />
<br />'Ooell'lOlln.clud. 12.600 ocr..f.., 01 dmllorog. b.IQw sns I..,.
<br />
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