7313 - Laserfiche WebLink

Home Browse Search

The virgin flow of the Colorado River at Lee Ferry5 for the 1990 water year amounted to 8,521,000 acre-feet.6 3. SUMMARY OF RESERVOIR LEVELS AND CONTENTS RunofF during the year ending September 30, 1990 ranged from 42.0 percent ofthe 77-year (1914-1990) mean at the Colorado River station near Cisco, Utah to 44.7 percent of the 77-year mean at the Green River station at Green River, Utah, The volumes of runoff at these stations were 2,284,900 acre-feet and2,023,500 acre-feet respectively. Runoffof the San Juan River station near San Juan, Utah totaled 826,400 acre-feet, which was 44.2 percent of the 77-year mean, Lake Powell's lowest elevation of the 1990 water year occurred on September 29, 1990 when the lake level was at elevation 3,637.58 feet (live content 16,249,000 acre-feet). Lake Powell was at its highest point on October 1, 1989 at elevation 3,665.20 feet with a content ofl9 ,805,000 acre-feet. A total of 8,251,000 acre-feet was released to the river below Glen Canyon Dam during the 1990 water year, The 1981-1990 (10- year) delivery to the Lower Basin (measured at Lee Ferry) was 128,280,000 acre-feet. Lake Mead, on September 30,1990, contained 20,143,000 acre-feet8 of available storage water at elevation 1,180,02 feet, On September 30, 1990, the live storage of Lake Mead was 3,891,000 acre-feet more than the storage in Lake Powell. · Virgin flow is the estimated flow of the stream if it were in its natural state and un- affected by the activities of man. 'Lee Ferry, Arizona is the division point between the upper and lower basins of the Colorado River as defined in the Colorado River Compact. It is located about one mile downstream from the mouth of the Paria River and about 16 miles downstream from Glen Canyon Dam. 6 Based on provisional records subject to revision. 7 Adjusted for the change in storage in Colorado River Storage Project Reservoirs, 8 Based on April 1, 1967 Capacity Table revised according to Sedimentation Survey 1963-1964. 10