Water Allocations Increase as Storms Improve Conditions, but Drought Remains
With March storms boosting reservoir levels, the Department of Water Resources (DWR) increased its water delivery estimate (allocation) for most recipients to 45 percent of requests for the calendar year.
DWR’s initial State Water Project (SWP) allocation of 10 percent of requests, announced in December, was increased to 15 percent on January 26 and to 30 percent on February 24 after January storms increased the Sierra snowpack and brought significant rainfall to the drought-parched state.
Although February was mostly dry, rain and snow returned this month to boost the state’s two largest reservoirs – Shasta Lake and Lake Oroville – to slightly above their historic levels for the date. Some key reservoirs, however, remain far below expected levels for this time of year.
The drought has not ended. Although California is on track to end the winter season with near-average conditions, one such season does not compensate for four prior years of drought. Accurately predicting whether water year 2017 will be wet, dry, or average is beyond the skill of climate forecasters, and we must be prepared for the possibility of a dry 2017. Even with reservoir levels rising, conservation is the surest and easiest way to stretch supplies.
“February reminded us how quickly California’s weather can turn from wet to dry,” said DWR Director Mark Cowin. “The lesson of this drought is that we all need to make daily conservation a way of life.”
Sacramento–San Joaquin River Delta in California, USA, looking northwest. The Sacramento River is above, the San Joaquin River below. The main island between is Sherman Island. At its upper tip on the left is Brannan Island with Brannan Island State Recreation Area occupying the small peninsula; at its upper tip on the right is Twitchell Island. Bradford Island is on the center right and Jersey Island in the right lower corner. The upper left is Solano County with the city of Rio Vista on the riverbank.
Thanks to March storms, DWR will not need to install a drought barrier this year to help control salinity in the Sacramento-San Joaquin Delta.
A drought barrier that spanned West False River between Jersey and Bradford islands for six months in 2015 was removed in November. The barrier prevented saltwater from encroaching with the tides into the central Delta from San Francisco Bay. The rock barrier helped to maintain water quality for Delta residents and millions of other Californians dependent on Delta water.
The 29 public agencies that receive SWP water (State Water Project Contractors) requested 4,172,786 acre-feet of water for 2016. With today’s allocation increase, they will receive 1,898,964 acre-feet.
Collectively, the SWP Contractors serve approximately 25 million Californians and just under a million acres of irrigated farmland.
The SWP provides the same allocation percentages to cities and farms. The U.S. Bureau of Reclamation, which operates California’s other major water project, the Central Valley Project (CVP), is expected to announce later this month its initial allocation to farms and cities. The SWP and CVP have different legal and contractual obligations and operational capabilities, and the CVP uses a priority system to allocate water.
Both agriculture and many communities have felt the pain of low, drought-year allocations from the state and federal water projects, with vast tracts of farmland fallowed and drinking water systems failing in some communities.
It is important to note that nearly all areas served by the SWP also have other sources of water, among them streams, groundwater and local reservoirs.
Key reservoirs are rising from winter storms, but some remain below average for the date.
Lake Oroville in Butte County, the State Water Project’s principal reservoir, early this morning was holding 2,708,486 acre-feet, 77 percent of its 3.5 million acre-foot capacity and 105 percent of its historical average for the date. Shasta Lake north of Redding, California’s and the CVP’s largest reservoir, was holding 3,850,207 acre-feet, 85 percent of its 4.5 million acre-foot capacity and 110 percent of its historical average. But San Luis Reservoir, a critical south-of-Delta pool for both the SWP and CVP, was holding only 990,970 acre-feet, 49 percent of its 2 million acre-foot capacity and just 55 percent of average storage for the date.
Folsom Lake, a CVP reservoir near Sacramento, has risen to 70 percent of its 977,000 acre-foot capacity, 117 percent of historical average for the date, and has had to make flood control releases to retain space for heavy inflow.
Groundwater aquifers recharge much more slowly than surface reservoirs, with many in the Central Valley falling toward record levels.
Last year’s (2015) 20 percent SWP 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 five percent of requested amounts for all customers.
The last 100 percent allocation was in 2006. Seven of the nine years since 2007 have been dry. SWP allocations in recent years:
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’s California Data Exchange Center (CDEC) Web sites show current water conditions at the state’s reservoirs and weather stations.
Reservoirs: http://cdec.water.ca.gov/cdecapp/resapp/getResGraphsMain.action
Precipitation: http://cdec.water.ca.gov/snow_rain.html
Snow: http://cdec.water.ca.gov/cdecapp/snowapp/sweq.action
Governor Edmund G. Brown Jr. declared a drought state of emergency in January 2014 and directed state agencies to take all necessary actions to respond to drought conditions. In April 2015, Governor Brown announced the first-ever 25 percent statewide mandatory water reductions and a series of actions to help save water, increase enforcement to prevent wasteful water use, streamline the state’s drought response and invest in new technologies that will make California more drought resilient. Californians have responded with unprecedented conservation efforts.
To date, guided by the California Water Action Plan, the state has committed hundreds of millions of dollars – including Water Bond funds – to emergency drought relief, disaster assistance, water conservation and infrastructure projects across the state. To learn about all the actions the state has taken to manage our water system and cope with the impacts of the drought, visit Drought.CA.gov.
Image: (bottom left) Islands, Sacramento River Delta, California-from Wikimedia Commons, the free media repository by worldislandinfo.com