Storage: A Critical Part of Water Supplies!

By Richard Atwater
SCWC Executive Director
September 7, 2011

Serious concerns about the Delta Stewardship Council’s Delta Plan are mounting quickly these days. Over the last few weeks, water leaders and stakeholders across the state have been lodging criticism about the fifth staff draft of the Delta Plan on a number of critical fronts.  We’ll have some further thoughts on the latest plan draft in my next blog piece but I wanted to highlight today a recent letter submitted to the Delta Stewardship Council on State Water Project and Central Valley Project operations.

Just last week, the State Water Contractors and the San Luis & Delta-Mendota Water Authority submitted a joint letter to the Delta Stewardship Council taking issue with several inaccurate statements in the draft plan that, according to the letter, “add up to a false portrayal of these two water systems.”

I would encourage you to read the quick letter. Getting the facts correct on these important issues is critical as state leaders embark on developing and implementing new statewide water policy. It’s also critical for the Delta Stewardship Council to recognize the important strides Southern California has made in the last two decades to improve the reliability of our water supplies. That contractors’ letter pointed out that in the last two decades, “public water agencies have spent hundreds of millions of dollars developing a network of reservoirs and groundwater banks to capture surplus waters in wet years.”  That flexibility in our system is critical.

In the arid southwest of the United States, storage of water supplies has always been a key part of ensuring adequate water supplies. Since Mulholland planned the Los Angeles Aqueduct (1900) and then in the 1920s the Colorado River Aqueduct, surface and groundwater storage were key factors in building these facilities to ensure water supply reliability.

Why?  Rainfall and snowpack are limited to relatively short seasons, typically October through April each year, throughout the arid southwest.  And, if we have low rainfall in the winter then shortages could occur without adequate storage.
Beginning in the early 1990s with the effect of the drought from 1988 to 1992, Southern California water managers recognized that the combined water supplies of the Los Angeles Aqueduct, Colorado River, and the State Water Project were inadequate to meet the regional water needs during below normal and drought conditions.

During the 1990s, key new surface reservoirs began construction in the region:  MWD’s $1.9 billion Diamond Valley Reservoir (the completion of MWD’s $1.2 billion Inland Feeder project allowed the doubling of State Water Project deliveries along the East Branch); the $1.5 billion Seven Oaks Dam (and enlargement of Prado Dam) and reservoir in the upper part of the Santa Ana River watershed dramatically increased flood control protection but also significantly increased the recharge of stormwater into the  groundwater basins.

Groundwater storage was also significantly expanded in Kern County with the water bank near Bakersfield and the large storage projects in Arvin-Edison and Semitropic.  Within the rest of the region -- from the Coachella Valley, Mojave River, Antelope Valley and Ventura County --groundwater storage projects were initiated.

During the past decade, more than $2 billion was spent on groundwater storage projects within the Santa Ana River watershed to reduce the region’s reliance on imported water supplies during future droughts, including the internationally recognized projects by Orange County Water District.  Today, every drop of water that flows on the Santa River is used and reused 2-3 times while being stored in a groundwater basin for use many years later.

In total, more than $7 billion has been spent during the past two decades throughout Southern California, from Bakersfield to Palm Springs to San Diego, to increase our surface and groundwater storage capacities and to help “drought-proof” our 20 million residents!  Still more needs to be done but the progress made during the past 20 years would have made Mulholland proud.

All these facts and important contributions are often lost in the many policy debates that abound in Sacramento. Here at SCWC, we believe it’s imperative to continue highlighting the many positive regional investments that our public agencies and municipalities have made in the past two decades to better utilize this precious resource.

Stay tuned for more thoughts on the developing Delta Plan...