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<br />WATER YEAR 1990 OPERATIONS <br /> <br />Green Mountain Reservoir <br /> <br />o <br /><~ Green Mountain Reservoir and Powerplant are located on the Blue River on <br />~ Colorado'$ western slope. The reservoir provides replacement storage for <br />o.? out-of-pr'iority depletion by the Project. <br />~ <br />(".J; Construct~on was completed in 1943. The reservoir has a total capacity of <br />154, 645 a~re-feet, with 52,000 acre-feet all ocated to repl acement storage. <br />The balance of about 100,000 acre-feet (including dead and inactive <br />storage) ;is allocated to power, natural flow shortage makeup, and other <br />water uses. The powerplant has two units with a total installed capacity <br />of 25.8 megawatts and a release capability of about 1,725 ft3/s, at low <br />reservoir' elevations. The spillway on the left abutment is gated with <br />three radial gates and has a total release capability of 25,000 ft3/s. <br /> <br />Reservoir:storage coming into water year 1990 was equal to 97,985 acre-feet <br />compared to an average September 30 storage of 128,400 acre-feet. <br /> <br />Colorado River native flows were below normal during October averaging <br />825 ft3/s ,at the Dotsero gauge and 1,571 ft3/s at the Cameo gauge. This <br />flow was ~ot adequate to meet downstream water user demands and resulted <br />in the nee:d for a call on Green Mountain Reservoir to maintain the required <br />flow of 1,850 ft3/s at the Cameo gauge through ~the October 28 irrigation <br />season. Turbine releases averaged 616 ft3/s for October 1-28 when the call <br />was on, arid 211 ft3/S for October 29-31 when the call was off . <br /> <br />Winter tu~bine releases (November through January) averaged near 160 ft3/s <br />to meet r~placement requirements, bypass of inflow, power production, and <br />the desi red end-of-January storage posi t ion. Green Mountai n Reservoi r <br />drawdown was scheduled to meet the normal target storage level of near <br />65,000 acre-feet for April 30. <br /> <br />The end 'of January storage for Dillon Reservoir was equal to <br />225,830 acre-feet. <br /> <br />The October-January precipitation was much below normal at 54 percent of <br />average, and the February 1 snowpack data was recorded at 88 percent of <br />average. <br /> <br />The Febru~ry I forecast of the April-July runoff volume totaled <br />240,000 acre-feet which was 89 percent of the recent 30-year (1960-1989) <br />average. ,Reservoir storage continued close to plan during February, and <br />releases cQntinued at about 160 fe/so Precipitation for February continued <br />to be much:below normal at 51 percent of average. This reduced the March I <br />forecast of the April-July runoff volume to 210,000 acre-feet. <br /> <br />Snowfall greatly increased in March' with 110 percent of average <br />precipitation recorded. Although it was a wet month, reservoir inflow was <br />below normal at 59 percent of average for March. <br /> <br />9 <br />