CALIFORNIA, Feb. 25, 2016 -- Winter storms have allowed the California Department of Water Resources to increase its estimated State Water Project water delivery allocation for most recipients to 30% of requests, up from a 15% estimate in late January, DWR announced today.
Officials warn water recipients, however, that extended dry weather could force an allocation reduction and the current remarkably dry February actually limited today’s allocation increase.
“Today’s increase, although good news, does not mean the drought is ending,” DWR Director Mark Cowin said in a written statement. “After more than four dry years, we still have a critical water shortage. We need a lot more wet weather this winter to take the edge off drought. Using water carefully and sparingly is still the quickest, most effective way to stretch supplies.”
In December, DWR made an initial allocation estimate of 10%.
According to DWR, the 29 public agencies that receive SWP water requested 4,172,786 acre-feet of water for 2016. With today’s allocation increase, they will receive 1,268,724 acre-feet. The 30% allocation announced today may be increased if storms bring more rain and snow.
DWR also stressed in its statement that outdated water delivery infrastructure in the Sacramento-San Joaquin Delta affected the new allocation increase. SWP pumping in the Delta has been limited this winter in order to minimize harm to native fish species. DWR estimates that 458,000 acre-feet of water – enough to supply 3.4 million people for a year – could have been captured if the new intakes, tunnels, and operating criteria proposed by California WaterFix had been in place. That project proposal is now undergoing environmental review.
Officials also stated that there is no exact formula for ending the drought and conditions vary region by region, but a rough guidepost is that approximately 150% of average winter precipitation – rain and snow – would significantly ease statewide conditions, with the major exception of groundwater depletion.
Key reservoirs are rising from early winter storms, but most remain low. Lake Oroville in Butte County, the SWP’s principal reservoir, early this morning was holding 1,808,410 acre-feet, 51% of its 3.5 million acre-foot capacity and 74% of its historical average for the date. Shasta Lake north of Redding, California’s and the federal Central Valley Project’s largest reservoir, was holding 2,690,554 acre-feet, 59% of its 4.5 million acre-foot capacity and 82% of its historical average.
San Luis Reservoir, a critical south-of-Delta pool for both the SWP and CVP, reflects the same trend of lower reservoir storage this year. San Luis was holding 854,623 acre-feet, 42% of its 2 million acre-foot capacity and 50% of normal for the date. Folsom Lake, a CVP reservoir near Sacramento, has risen to 64% of its 977,000 acre-foot capacity, 117% of its historic average for the date. Folsom fills more rapidly than many other reservoirs due to its relatively small size compared with its huge watershed.
Last year’s 20% allocation was the second lowest since 1991, when agricultural customers of the SWP got a zero allocation and municipal customers received 30 percent of requests. In 2014, SWP deliveries were 5% of requested amounts for all customers.
The last 100% allocation – difficult to achieve even in wet years largely because of Delta pumping restrictions to protect threatened and endangered fish species – was in 2006.
