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Show Sub-Normal Runof f in Colorado River May has been the third consecutive month of sub-noimai sub-noimai precipitation in the Colorado River Basin above Lees Ferry, causing the April-July runoff forecast to fall to 7.4 million acre-feet, or 87 per cent of normal, tne Bureau of Reclamation announced an-nounced Wednesday. An even ev-en lower forecast is avoided only by the presence of above normal snow accumulations accumu-lations in the high mountains. moun-tains. Another milestone was reached last month in the utilization of water of the Colorado River in the Upper Basin. On Thursday nignt, May 22, water stored in Lake Powell reached elevation eleva-tion 3570 feet, which is "rated "rat-ed head" for the powerplant located at the toe of Glen Canyon Dam. "Rated head" is tne lowest level at which water flowing through the turbines can drive the generators gen-erators at their nameplate capacity. With normal rainfall, rain-fall, it is expected that Lake Powell's water surface should reach an all-time higrt "in July at about elevation 3580 feet with a live storage of. about 10,290,000 acre-feet. Planned releases from Lake Powell for water year 1969 are about 8.8 million acre-feet. acre-feet. For the next 3 years thereafter annual releases should be near this amount in order to deliver Colorado, River Compact requirements to the Lower Basin. The entire en-tire release will be used to generate power for power customers in both the Upper Up-per and Lower Basins. About 985,000 acre-feet of runoff should originate above -Flaming Gorge Dam. If this amount is realized, about 175,000 acre-feet will be stored stor-ed in Fontenelle Reservoir which is located upstream, and the remainder of the runoff will be regulated at Flaming Gorge Reservoir. Flaming Gorge Reservoir is now about elevation 5982 feet and a live storage content con-tent of 1,833,000 acre-feet. The reservoir will be maintained main-tained near this level until drawdown in the winter of 19G9-70. On the San Juan River, Navajo Lake should receive about 750,000 acre-feet of spring runoff, raising its level le-vel another 3 feet to elevation eleva-tion 6040 feet during June. By the end of August the lake should recede to elevation eleva-tion 6030 and will be maintained main-tained near this level until drawdown occurs during the . winter months. Runoff forecast for the Gunnison River watershed above Blue Mesa Dam is 640,000 acre-feet. The reser- VU1I 13 I1UW UL eievcuiuu 10D feet with a live storage content con-tent of 550,000 acre-feet. It should reach about elevation 7499 feet by the end of August Au-gust with a live storage of 650,000 acre-feet. Lake Mead is now about elevation 1141 feet or about 6 feet higher than a year ago. It contains 15.5 million acre-feet of available storage stor-age or 57 per cent of its capacity. ca-pacity. The lake is scheduled schedul-ed to rise slowly during the remainder of the year. Required Re-quired compact releases from Lake Powell will probably pro-bably exceed Lower Basin water requirements during the next 3 years, so a nom- inal rise in Lake Mead during dur-ing this period can be expected. |