WSP05551 - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I 2001 OPERATIONS SUMMARY AND RESERVOIR STATUS Water year 200 I was the second consecutive year with dry hydrologic conditions in the Colorado River basin. The distribution of precipitation and sno'W-pack throughout the basin varied, however. Snowpack and runoff conditions in the northern portions of the basin were much below average, while near average conditions existed in the south. April through July runoff into Flaming Gorge Reservoir, for instance, was only 36 percent of average, while runofffor the same period was 107 percent of average for Navajo Reservoir. While water year 2001 ended up being drier than normal in the Colorado River basin, hydrologic conditions appeared favorable as water year 200 I began. Upper Colorado basinwide snowpack on January 1, 200 I was 92 percent of average. Early season inflow projections for Colorado River reservoirs were also near average. Drier than normal conditions, with below average precipitation, were observed in the late winter and spring, however. During the April through July runoffperiod, periodsofwarm windy weather compounded the situation, contributing to loss of snowpack and reducing runoff efficiency. Unregulated April through July inflow to Lake Powell in 2001 ended up being only4.30 MAF (5,304 MCM) or 56 percent of average. This was nearly identical to the 4.3 5 MAF (5,370 MCM) of April through July unregulated inflow obser,-'ed in water year 2000. Water year 2001 unregulated inflow into Lake Powell was 6.96 MAF (8,580 MCM), or 59 percent of average. This below average inflow resulted in a decrease of approximately 1.80 MAF (2,230 MCM) of storage in Lake Powell. Storage in reservoirs upstream of Lake Powell decreased by approximately 0.02 t\.lAF (25 MCM). In Lower Basin reservoirs, storage decreased by approximately 2.48 MAF (3,060 MCM). Total Colorado River system storage decreased by approximately 4.31 MAF (5,310 MCM) during water year 2001. Even with this decrease in storage, Colorado River reservoirs remain relatively full with total system storage at 76 percent of capacity as of September 30, 200 I. During 200 I, all deliveries of water to meet valid obligations pursuant to applicable provisions of "The Law of the River" were maintained. Tables I(a) and l(b) list the October I, 2001, reser-.-'oir vacant space, live storage, water elevation, percent of capacity, change in storage, and change in water elevation during water year 2001. October 15, 200 1 3