The news of the annual water carry-over from the Bureau of Reclamation’s Central Valley Project (CVP) is a far cry different this year versus anything from the past five years. As CVP began Water Year (WY) 2017/18 – which runs Oct. 1, 2017 to Sept. 30, 2018 – the carry-over from WY 2016/17 was 8.9 million acre-feet of storage. This reflects 145 percent of the 15-year average annual carryover of 6.2 million acre-feet for the six key CVP reservoirs (Trinity, Shasta, Folsom, New Melones, Millerton, and the federal share of the joint federal-state San Luis Reservoir).
“2017 was an incredible water year, and we are pleased to have bountiful water supplies,” said Regional Director David Murillo. “Now we are focusing on balance. We are heading into winter with our reservoir levels at a safe place with respect to flood control, should we experience another wet winter. At the same time, we believe we have conserved healthy storage levels in the event that we have a dry winter.”
The CVP is the largest single source of irrigation water in the state, typically supplying water to about 3-million acres of agricultural land in the San Joaquin and Sacramento valleys and along California’s central coast. The CVP also provides urban water for millions of people and industrial water which are essential to the San Francisco Bay Area’s economy.
Water from the CVP is also crucial for the environment, wildlife and fishery restoration, and hydroelectric power production. During WY 2017, CVP power plants generated about 6.1 billion kilowatt-hours. Project use consumed about 20 percent of this energy while the remaining energy was made available for marketing.
In light of California’s multi-year drought, which ended for virtually all of the state earlier this calendar year, the comparison of previous years’ end-of-year storage in the six key CVP reservoirs is vast. The six combined million acre-feet in CVP reservoirs’ storage have been:
Water Year (WY) Carry-over
2016/17 8.9
2015/16 4.9
2014/15 2.9
2013/14 3.1
2012/13 5.1
1976/77 (driest year) 1.5
1982/83 (wettest year) 9.8
Individually, the six key reservoirs statistics for capacity, carry-over, percent of capacity and the 15-year average storage are reflected below. (NOTE: Capacity, 2016/17 Storage and 15-Year Storage are reflected in million acre-feet.):
The amount of stored water at the end of the water year reflects the amount carried over into the new water year. One acre-foot is the volume of water sufficient to cover an acre of land to a depth of 1 foot, enough water to sustain a typical California household of four for one year.
In spring 2018, Reclamation anticipates making a preliminary assessment of WY 2018 CVP water supply conditions. Throughout 2018, Reclamation will continually monitor and evaluate hydrologic conditions and will adjust water supply allocations, as warranted, to reflect updated snowpack and runoff. Current allocations and background information are available at www.usbr.gov/mp/cvp-water/.