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<br />2002 OPERATIONS SUMMARY AND RESERVOIR STATUS <br /> <br />Extremely dry hydrologic conditions were observed in the Colorado River basin in water year 2002. <br />Basinwide precipitation was only 48 percent of average and snowpack accumulations were much <br />below normal levels. As the spring snowmelt season began on April 1, 2002, snowpack levels <br />throughout the Colorado River Basin were generally less than 50 percent of average. The situation <br />was particularly severe in the central and southern portions of the Upper Colorado River basin. <br />Many reservoirs in the Colorado River Basin recorded record low inflows during 2002. These <br />included Navajo Reservoir, Blue Mesa Reservoir and Lake Powell. Unregulated(1) inflow into Lake <br />Powell during the April through July runoff period in 2002 was only 1.12 maf(1,380 mcm) or 14 <br />percent of the 30 year average(2). Total unregulated inflow into Lake Powell for water year 2002 <br />was only 3.06 maf(3,780 mcm) or 25 percent of average. This was the lowest recorded since the <br />closure of Glen Canyon Dam in 1963. The previous low was observed in 1977 when water year <br />unregulated inflow was 3.66 maf (4,510 mcm) or 30 percent of average. <br /> <br />Not only was water year 2002 a very low year for runoff in the Colorado River basin, but it also <br />marked the third consecutive year with below average inflow into Colorado River reservoirs. <br />Reservoir storage continued to decline for the third straight year. Storage in Lake Powell decreased <br />by 4.67 maf (5,760 mcm) in 2002. Storage in reservoirs upstream of Lake Powell decreased by <br />approximately 1.06 maf (1,300 mcm). In Lower Basin reservoirs, storage decreased by 2.80 maf <br />(3,460 mcm). At the beginning of water year 2002, Colorado River total system storage was 76 <br />percent of capacity. Total Colorado River system storage decreased by approximately 8.52 maf <br />(10,500 mcm) during water year 2002. As of September 30, 2002 total system storage was 64 <br />percent of capacity. <br /> <br />Even though Colorado River reservoir storage has been reduced, during 2002, all deliveries of water <br />to meet valid obligations pursuant to applicable provisions of "The Law of the River" were <br />maintained. <br /> <br />Preliminary Colorado River water delivery accounting data for calendar year (CY) 2002, compiled <br />pursuant to Article V of the Decree, indicated that requests for water deliveries by agricultural users <br />in California during CY 2002 had the potential to exceed the maximum amount of water available <br />under the determinations made in the 2002 AOP approved and transmitted on January 14, 2002. In <br />light ofthe potential for such overuse within the Lower Basin, and after consultation with members <br />of the CRMWG, a supplement to the 2002 AOP was approved on November 22, 2002. The <br /> <br />(1) Unregulated inflow adjusts for the effects of operations at upstream reservoirs. It is computed <br />by adding the change in storage, and the evaporation losses from upstream reservoirs to the <br />observed inflow. Unregulated inflow is used because it provides an inflow time series that is not <br />biased by upstream operations, and more closely resembles natural flow conditions. <br />(2) Inflow statistics throughout this document will be as compared to 30 year averages. <br /> <br />December 13,2002 <br /> <br />4 <br />