State water supply rises after Dec. rain

December storm runoff and close coordination among federal and state agencies to take advantage of it will allow the California Department of Water Resources (DWR) to increase expected water deliveries in 2015 to most customers of the State WaterProject (SWP) from 10% of their requested amounts to 15%. The new allocation replaces the initial allocation of 10% announced on Dec. 1.

With the U.S. Bureau of Reclamation, operator of the Central Valley Project (CVP), DWR also submitted to state regulators a drought contingency plan that highlights potential modifications to water quality rules and water rights permits that project operators may seek, depending on the weather.

The early submittal of the plan to the State Water Resources Control Board reflects an unprecedented level of coordination and planning among the state and federal agencies that either operate water projects based in the Sacramento-San Joaquin Delta or regulate those projects. Tight coordination in recent months allowed the projects to store storm runoff without violating statutory and regulatory obligations to protect water quality and wildlife.

A few storms reached California last month, but there have been none since Dec. 21. It will take sustained levels of significant snow and rain to ease the drought, now in its fourth year. Water conservation by residents and businesses across the state remains critically important.

Since the December rains, more than 450,000 acre-feet (AF) of water have been moved into San Luis Reservoir, a critical south-of-Delta pool for both the SWP and the federal CVP. Both projects have ready access to this increased storage south of the Delta to meet their contractors’ needs. The 29 public water agencies that take delivery of SWP supplies have requested 4,172,686 AF. With the new allocation, contractors will receive 635,759 AF. If the contractors’ health and safety needs cannot be met by that allocation, DWR may increase deliveries to satisfy those needs. An acre-foot is roughly enough water to meet the needs of a family of four for one year.

Increased storage in the state’s major reservoirs gave DWR’s water managers confidence they can deliver the higher allocation. Lake Oroville, the SWP’s principal reservoir, held 828,220 AF on Nov. 21. The lake’s storage today is 1,396,535 AF, an increase of nearly 570,000 AF. Nevertheless, Oroville’s average storage for this date is more than 2,234,000 AF, so the current storage is only 62 percent of average for mid-January.

DWR Director Mark Cowin said although allocations have been increased, the current divergence from average conditions due to the drought makes water conservation as important as ever. “We cannot stress enough,” he said, “that water conservation will be critical in stretching our supplies to the maximum extent possible throughout the coming year.”

Cowin noted that dry conditions have been the norm since the December storms. Northern California has had virtually no rain for the past three weeks, and the near-term weather forecast predicts little if any precipitation. The Sierra snowpack, normally an important source of water during the summer and fall, today has a statewide water equivalent of only 4.9 inches, just 36% of normal for Jan. 15.

One year ago, DWR reduced its initial allocation to contractors of 5 percent to zero, the first ever such allocation for all SWP contractors. Storms in February and March allowed managers to increase the allocation back up to 5%. 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% of requested amounts.

The final SWP allocation for calendar year 2013 was 35% of requested water amounts. In 2012, the final allocation was 65%. It was 80% in 2011, up dramatically from an initial allocation of 25 percent. The final allocation was 50% in 2010, 40 percent in 2009, 35% in 2008 and 60% in 2007. The last 100% allocation – difficult to achieve even in wet years because of Delta pumping restrictions to protect threatened and endangered fish species – was in 2006.

California’s Water Year 2014 – overlapping with California’s driest calendar year of 2013 — was the third driest in 119 years of record, based on statewide precipitation. When Water Year 2014 ended on September 30, the state’s reservoirs tracked by DWR collectively held only 60% of average storage for the date, or 41% of capacity. Cumulative reservoir storage on the same date in the deep drought year of 1977 was five million AF less, but California had 16 million fewer people in 1977.

In January 2014, Governor Edmund G. Brown Jr. declared a drought state of emergency and issued statewide water conservation goals. The state recorded 5,620 fires during calendar year 2014 resulting in 90,606 acres burned, about 1,000 fires more than the annual average of the preceding five years. Vast tracts of farmland have been fallowed and some communities have been short on drinking water.

Long-range weather forecasts are uncertain, and it’s not known whether this winter will alleviate or deepen the drought.

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