The total reservoir storage is the combined amount of water remaining at the end of the 2009 water year in Shasta, Trinity, Folsom, and New Melones Reservoirs and the federal share of the joint Federal/State San Luis Reservoir. The 15-year average carryover for these reservoirs is 6.7 million acre-feet of storage (59 percent of capacity).
Precipitation in last season was about 94 percent of average or 47 inches according to the California’s Northern Sierra Nevada 8 Station Index. The seasonal average for precipitation is 50 inches. While last season approached average precipitation levels for Northern California, runoff remained low at about 70 percent of normal due to the three years of dry conditions. In the CVP, runoff is a better indicator for water supply availability than precipitation.
During the past five years, the CVP delivered an average of about 6 million acre-feet of water annually for agriculture, cities, and the environment. The 2009 CVP contract year deliveries are generally based on the period March 1 through Feb. 28 each year and are estimated to be 5.3 million acre-feet.
Last season CVP power plants generated about 3.6 billion kilowatt-hours, enough power to run 360,000 homes for a year. Project-use consumed about 33 percent of this energy. The remaining energy was made available for marketing. Mid-Pacific Region generators have a combined capacity of approximately 2.1 million kilowatts.
The Friant Division estimated deliveries for the 2009 contract year are 1.19 million acre-feet, which is 103 percent of the historic water supply of 1.15 million acre-feet. This total includes 800,000 acre-feet of Class 1 and 392,000 acre-feet of Class 2 water. The final allocation for Friant Division contractors is 100 percent of Class 1 and 28 percent of Class 2 water. The precipitation total for the San Joaquin River watershed was 34.69 inches or 78 percent of average and the runoff for the San Joaquin River was 1.46 million acre-feet (79 percent of normal).
The initial forecast of CVP water supply allocations for 2010 will be made in late February 2010. The allocation will be adjusted monthly thereafter to reflect the updated snowpack and runoff information.