OCR Text |
Show Heaviest Spring Colorado River Runoff in Years The April through July ' jnowmf It runoff in the Colors-' Colors-' jo River Basin will bo the highest in 10 years the Bureau Reclamation predicted this k- ... Riverflow originating above Ule Poc'l behind Glen Cmyon Dam for this period ilf total 10.5 million acre-feet, acre-feet, or 134 per cent of the Ions-term average. This will fce 1.3 million acre-feet less than the runoff in ltv5 but 3.5 million acre-feet more than the jg4 April-July runoff. A runoff of 14.6 million acre-feet acre-feet for the w ater year ending September 30 is forecast compared w ith a runoff of 10.4 million acre-feet for the previous w ater year. Lake Powell is now at ' elevation 3,663 feet above mean sea level and rising. It '' contains 19 million acre-feet of usable storage. By midsummer midsum-mer the reservoir will rise ibout 1 more feet to elevation 3,6"9 feet above mean sea level or 12 feet higher than it reached last year. ' About 1.4 million acre-feet of the spring runoff is expected to originate in the Green River drainage above Flaming Gorge r:Dam. Of this amount 150,000 ' tore-feet will be stored in Fontenelle Reservoir, while I the remainder will be regulat-ed regulat-ed at Flaming Gorge Reservoir. Reser-voir. Inflow down the Green "River will fill Flaming Gorge 1 Reservoir to elevation 6,040 '"feet above m.s.l. by the end of f3uly, with a usable content of 3,750,000 acre-feet. Fonte-'nelle Fonte-'nelle Reservoir should fill to its Wmaiimum capacity of 345.000 'acre-feet at elevation 6,506 sTeet during the first part of July and will then hold near "full through August. The reservoir will be slowly drawn down to elevation 6,480 feet during the winter months. In Colorado, Blue Mesa Reservoir is expected to receive about one million acre-feet of inflow from the Gunnison River during the April-July period, or about 127 per cent of the long-time average. Releases from Blue Mesa Dam (w hich pass almost unchanged through Morrow Point Reservoir and Power-plant), Power-plant), when added to by side stream inflows, will cause a flow past Crystal Dam site of about 4,000 cubic feet per second during the snowmelt season. As runoff into Blue Mesa decreases, releases will be reduced accordingly. Blue Mesa is expected to fill to elevation 7,519 above m.s.l. by the end of July 1975 with a capacity of 830,000 acre-feet. Morrow Point Reservoir should remain full, capacity 117,000 acre-feet, throughout this period. Above normal snowpacks in the San Juan drainage area will cause Navajo Reservoir to reach elevation 6.062 feet above m.s.l. by the end of June 1975. It will be maintained maintain-ed near this high mark through the summer months for recreation purposes. Releases are expected to be about 1,500 cubic feet per second during the fall and winter months prior to the 1976 spring runoff. Lake Mead's present elevation eleva-tion is 1,174 feet above m.s.l. or about 5 feet higher than a year ago. The reservoir is now 47 feet below the top of the raised spillway gates of Hoover Dam. At present it contains 19.4 million acre-feet of available storage or 74 per cent of its capacity. Based on the present forecast. Lake Mead is expected to rise to about elevation 1,186 feet above m.s.l. by the end of September. |