Early season storms allow State Water Project supply allocations to jump from 20 to 45 percent

The Department of Water Resources (DWR) announced this week that thanks to December storms its early-season estimate of next year’s State Water Project (SWP) supply has been boosted from 20 to 45 percent for most requests. But DWR has also cautioned that the early storms have only dented California’s multi-year drought and that Californians should continue all conservation efforts.

DWR makes its initial estimate of the SWP water delivery capability and projected allocation in December of each year for the following calendar year. As hydrologic conditions develop throughout the rainy season the allocation is adjusted.

“This winter’s wet start gives us hope we’ll be able to keep increasing the State Water Project allocation,” said DWR Director Mark Cowin. “But the faucet can shut off suddenly and leave us dry for a sixth year in a row. Drought always looms over California, so we must use water wisely and sparingly.”

Based on the recent DWR projected increase to 45 percent the 29 agencies served by the SWP will receive 1,894,645 acre-feet of water. The total water request of the combined agencies is 4,172,786 acre-feet. Under the earlier 20 percent allocation these same agencies would have received just 839,376 acre-feet.

Key reservoirs throughout the state are posting encouraging totals thus far this year.  Earlier this week, Lake Oroville in Butte County, the SWP’s principal reservoir was holding 1,895,292 acre-feet, 54 percent of its 3.5 million-acre-foot capacity and 88 percent of its historical average for the date. Shasta Lake north of Redding, California’s and the federal Central Valley Project’s (CVP) largest reservoir, was holding 3,327,257 acre-feet; this represents 73 percent of its 4.5 million-acre-foot capacity and 120 percent of its historical average. San Luis Reservoir, a south-of-the-Delta storage facility for both the SWP and CVP, was holding 1,155,838 acre-feet or 57 percent of its 2 million-acre-foot capacity and 87 percent of its average for the date.

The December 2015 initial allocation for the 2016 calendar year allocation was just 10 percent of the requested 4.1 million acre-feet.  However, as storms developed and reservoir storage increased, the 2016 allocation was increased to 60 percent. Nearly all areas and agencies served by the SWP have other sources of water in addition to what they receive from SWP.  These include groundwater, local reservoirs and various bodies of water.

As the state looks forward to the new year – and hopefully more precipitation to mitigate some of the effects of the five-plus year drought — the DWR’s California Data Exchange Center Web sites will continue to update current water conditions at the state’s largest reservoirs and weather stations. Data can be found as follows:

Reservoirs: http://cdec.water.ca.gov/reservoir.html

Precipitation: http://cdec.water.ca.gov/snow_rain.html

Snow: http://cdec.water.ca.gov/snow/current/snow/index.html

SWP allocations for the past 10 years shows the impact the state’s drought has had on allocations and the very few years with allocations above even 75 percent:

2016 – 60 percent

2015 – 20 percent

2014 – 5 percent

2013 – 35 percent

2012 – 65 percent

2011 – 80 percent

2010 – 50 percent

2009 – 40 percent

2008 – 35 percent

2007 – 60 percent

2006 – 100 percent

DWR notes that 100 percent allocations are difficult to achieve, even in wet years, due to Delta pumping restrictions to protect threatened and endangered fish species.