The 29 public water agencies that receive water through California’s State Water Project have tentatively been told to expect 10 percent of the 4.1 million acre feet of water they requested for the coming water year.
As with every year, these early allocation figures depend on the next several months and how much rain and snow California can accumulate and store for later release.
Improved precipitation forecasts this week allow the California Department of Water Resources (DWR) to set the initial allocation for 2015 at 10 percent, up from the five percent allocation SWP customers got this year.
The level of Lake Oroville – the keystone reservoir of the SWP system and a source of water for 25 million Californians – is rising due to recent storms, but is doing so after hitting its lowest level ever of less than 900,000 acre feet of storage just before Thanksgiving. The reservoir holds 3.5 million acre feet at capacity.
DWR officials say the state’s major reservoirs, including Oroville, are too depleted to be filled by a typical winter storm. DWR experts estimate that it will take roughly 150 percent of average precipitation for California to recover from drought.
“Storms in the extended forecast give us hope that we will return this winter to normal or above-normal precipitation levels after three years of drought,” said DWR Director Mark Cowin. “But we must be cautious and preserve adequate storage in reservoirs should conditions turn dry again.”
The California Farm Water Coalition called Cowin’s decision “good news” but recognizes that the season is still early and the final figure could fluctuate depending on the coming rainy season, which typically runs from November through March.
Drought not over
According to Farm Water Coalition Executive Director Mike Wade, Cowin’s decision “does not signal an end to the drought or environmental regulations that have resulted in low deliveries to farms, homes and businesses.”
According to Wade, the SWP delivers water to one million acres of farmland with an additional two million acres of California farmland serviced by the federal Central Valley Project. California agriculture’s two main sources of water are state water under the State Water Project, and federal water under the CVP.
CVP contractors received zero water allocations in the previous water year because of the drought.
Farmers receiving water from the CVP must wait until early next year to learn if the U.S. Bureau of Reclamation will deliver any water, according to Wade.
It is important to note that nearly all areas served by the SWP also have other sources of water, including streams, groundwater and local reservoirs. Also, the State Water Project contractors will have access to any water they have left in storage from previous allocations.
DWR also approved requests for delivery in 2015 167,465 acre-feet of carryover water from previous years.
DWR is hopeful that the preliminary SWP allocation will increase as storms bring rain and snow to the state. If severely dry conditions develop, the allocation may be reduced. Under extreme drought conditions, the Department may re-allocate supplies based on human health and safety requirements.
On average, half of California’s precipitation occurs December through February, and three quarters from November through March.
“We will still need to conserve even when we see storms develop,” said Cowin. “It will take more than a normal winter to make up for three consecutive dry years, and using less water in our homes will keep more in our critically low reservoirs.”
As the drought pushed into its third year, DWR on Jan. 31 dropped its initial water allocation (percentage of water requested) for calendar year 2014 from five percent to it’s first-ever zero allocation for all SWP contractors.
Storms in February and March boosted the allocation back up to 5 percent, making a little more than 200,000 acre-feet available to the 29 contractors, who collectively had requested slightly more than four million acre-feet.
Record low deliveries
The only previous zero allocation in the 54-year history of the SWP was for agriculture in 1991, but cities and others that year received 30 percent of requested amounts.
This year’s 5 percent allocation was the lowest final calendar year allocation in SWP history as a sparse mountain snowpack melted early and rainfall was near record lows in most parts of the state.
Final SWP allocation for previous years was as follows:
- 2013 – 35 percent
- 2012 – 65 percent
- 2011 – 80 percent
- 2010 – 50 percent
- 2009 – 40 percent
- 2008 – 35 percent
- 2007 – 60 percent
- 2006 – 100 percent
Officials say that a 100 percent allocation is difficult to achieve, even in extremely wet conditions, because of pumping restrictions in the Delta because of threatened and endangered fish species.
As the water year (Oct. 1-Sept. 30) ended, the state’s reservoirs tracked by DWR collectively held 60 percent of average storage for the date, or 41 percent of capacity. Cumulative reservoir storage on the same date in the deep drought year of 1977 was five million acre-feet less, but California had 16 million fewer people in 1977.
Weather forecasters are relatively confident that the next 30 days could be wet for all of California as projections indicate that five to 20 inches of rain could fall on much of California over the next month. One weather forecast model suggests the watersheds of northern California could see more than a foot of total rain over the next 30 days.