Enhancing Water Supply Reliability

A safe, reliable water supply is crucial for the vitality of the San Diego region’s economy and quality of life of its residents. To maximize the reliability of the region’s water supply, the San Diego County Water Authority is executing a long-term strategy to diversify the region's supply sources, make major investments in the region’s water delivery and storage system, and improve water use efficiency.

Supply Diversification

In 1991, the San Diego region was 95 percent reliant on a single supplier of imported water – the Metropolitan Water District of Southern California (MWD). This made the region extremely vulnerable to water supply shortages. That year, an ongoing drought forced MWD to cut deliveries to the San Diego region by 30 percent.

Regional Water Supply Portfolio Diversification

Click image above to enlarge.

As a result of that crisis, the Water Authority Board approved a strategy to aggressively diversify its water supply portfolio by developing new local and imported water supplies. This strategy already is enhancing regional supply reliability. By fiscal year 2011, the San Diego region had reduced its reliance on MWD supplies to 47 percent. This has lessened the impact of current water cutbacks from MWD that began in July 2009.

The Water Authority is working with its 24 local member retail agencies to develop local supplies such as groundwater, recycled water, seawater desalination, and conservation. By 2020, local water supplies are projected to meet 40 percent of the region’s water demand.

The Water Authority also has secured new imported water supplies through a long-term (45 to 75 years) water conservation and transfer agreement with the Imperial Irrigation District. The deal, reached in 2003, will provide 70,000 acre-feet of highly reliable Colorado River water in 2010 and increases to 200,000 acre-feet annually by 2021.

The Water Authority also has a separate, 110-year agreement to receive Colorado River water conserved by lining parts of the Coachella and All-American canals. These projects provide 80,000 acre-feet of water to the region annually.

What is an Acre-Foot?

An acre-foot is 325,900 gallons – roughly enough to submerge an entire football field a foot deep. It's approximately the supply used by two single-family households of four people for a year.

Improving Infrastructure

The San Vicente Dam Raise project will be completed by 2014.

The Water Authority also is in the final stages of executing a $3.8 billion Capital Improvement Program to further improve regional water delivery and storage capacity. The program includes 50 different projects, including new reservoirs, pipelines, pumping stations and a regional water treatment facility. Major projects under way include raising San Vicente Dam in East County by 117 feet to provide 152,100 acre-feet of additional local storage, and connecting Lake Hodges to the region’s imported water distribution system.

Water-efficient landscapes help stretch the region's water supply.

Promoting Conservation

In addition to developing new water supplies, it makes sense for the region to use its existing water resources as wisely and efficiently as possible. That’s why conservation has been a key component of the Water Authority’s supply diversification strategy for the last two decades. The Water Authority works with its member agencies and other partners to offer programs that improve water use efficiency for residential, commercial, and agricultural users and help promote conservation as a way of life in the San Diego region.

Conservation tips and program information is available at 20gallonchallenge.com.

The Water Authority is partnering with its local retail member agencies and The Home Depot to generate a greater awareness and encourage more use of water-efficient landscapes in the region. San Diego County residents interested in making their yards and gardens more attractive and water efficient will have a great opportunity to get information from gardening experts and save as much as 50 percent on select varieties of low-water-use plants at San Diego County Garden-Friendly Plant Fairs this spring at select The Home Depot locations. Click here for details.