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LAKE POWELL (COLORADO RIVER) Water Year 1988 Lake Powell, which is impounded by Glen Canyon Dam, was operated as part of the Colorado River Storage Project (CRSP) in accordance with governing contracts and laws to provide conservation storage,- river regulation, power generation, recreation, and fish and wildlife enhancement during water year 1988. - At the start of water year 1988, Lake Powell was 92 percent full with an active storage content of 23.1 MAF at elevation 3,687.9 feet The most probable operating plan based on the October forecast called for total water year releases of 105 MAF based on an unregulated inflow of 11.6 MAF. The reasonable maximum (upper decile) water supply had scheduled water year releases of 15.5 MAF based on an unregulated inflow of 17.7 MAF. On January I, 1988, Lake PoweU was at elevation 3,685.2 with an active content of22.7 MAF. The January 1 forecast of April through July runoff for Lake Powell was 6.8 MAF or 83 percent of the long-term average. Discharges from Glen Canyon powerplant averaged 13,800 cfs (42 percent of ACTUAL RELEASES WY 1988 1000 OF' .. .. .. NDJFMAMJJASO maximum capacity) for January ,and February. The runoff forecast on March 1, was 7.2 MAF or 88 percent of average, and releases from the powerplant averaged 11,400 cfs for the month. Subsequent monthly forecasts continued to decline until on June 1, the forecast was 5.1 MAF or 63 percent of 'average. To insure filing Lake Powell as full as possible by the end of June, powerplant releases were reduced to an average 28 percent of ,capacity for April through June. The maximum lake'elevation of 3,693.1 feet (% percent full) was reached on July 5, with an a.ctive content of 23.9 MAF. Lake Powell recorded a peak regulated inflow of 34,900 cfs on May 22. Maximum releases from the powerpJant during the spring runoff period averaged daily peaks of 9,000 to 12,000 cfs. The total 1988 water year unregulated inflow to Lake Powell was 8.16 MAF which is equivalent to 68 percent of the long-term average yearly supply. Total 1988 water year releases below Glen Canyon were 8.23 MAF which is the , minimum volume release. All releases were passed through the powerplant The spillways at Glen Canyon were not used. LAKE POWELL Reservoir Acre,feet Elevation, feet Maximum Storage Rated Head Minimum Power Surface Area, full Reservoir Length, full 25,002,000 9,428,000 4,126,000 3,700 3,570 3,490 161,390 Acres 186 Miles Powerplant Number of Units Total Capacity 8 1,247,000 KW 13