Benefits to Environment Glen Canyon to Hoover Dams

Most spectacular are the changes affected at Lake Mead, whose useful life is being greatly extended by retention of sediment in her sister, 27,000,000 acre-ft Lake Powell, formed 370 river miles upstream by Glen Canyon Dam. Cold water releases from the depths of Lake Powell for power generation at Glen Canyon Power Plant arrive at Lake Mead about 5-1/2°F cooler than the former unregulated flows. Annual rates of surface evaporation at Lake Mead are being reduced approx 10% (8 in in depth) with a substantial water savings of 75,000 to 100,000 acre-ft annually. The water savings could supply 90 gal per person per day to 1,000,000 people. These positive benefits, incident to the fundamental purpose and operation of the Glen Canyon Dam, improve for mankind the environment of the Colorado River system between Glen Canyon and Hoover Dams. Such benefits are too often overlooked by those critics of the builders and operators of large dams.