Groundwater replenishment system being explored to meet water supply needs

April 1998

U.S. Water News Online

FOUNTAlN VALLEY, Calif. -- Two major Orange County agencies that manage water resources announced a proposed system to create a new, safe, and reliable supply of high-quality water designed to satisfy north and central Orange County's thirst for years to come.

The Orange County Water District and the County Sanitation Districts of Orange County have begun environmental review of a proposed Groundwater Replenishment System that would reduce Orange County's dependence on expensive water purchased from the Colorado River and the State Water Project, and help protect it from future droughts.

The system would help meet the water-demand challenge for a 350-square-mile area of north and central Orange County now home to two million residents. By 2020, a projected three million residents would live in the area and require an additional 150,000 acre feet of water annually. If the agencies decide to proceed, the Groundwater Replenishment System initially would produce 50,000 additional acre-feet of water annually and could produce up to 100,000 acre- feet annually. Ultimately, the system could meet two-thirds of the additional water demand projected.

The proposed Groundwater Replenishment System would divert highly treated wastewater currently discharged into the ocean and treat it with a sophisticated process, including microfiltration, reverse osmosis, and purification. Water intended for drinking would be allowed to recharge into groundwater supplies from spreading ponds, following the same natural filtering path rainwater takes through the ground.

This purified and blended water ultimately would be made available for household uses, including drinking, cooking, and bathing. Some of the water would provide groundwater protection from seawater intrusion and a small portion would be used for landscape irrigation and industrial needs.

"The Groundwater Replenishment System would produce water of higher quality than Santa Ana River water currently used to recharge the groundwater basin," said Orange County Water District Director Philip Anthony. This purified water would meet all state and federal drinking water standards end would help ensure a safe, reasonably priced, and high-quality water supply for Orange County residents, even during periods of drought."

The Groundwater Replenishment System will undergo extensive scrutiny by local, state, and federal officials as well as the public in a thorough feasibility study and environmental analysis designed to refine project options, identify any potential problems, and respond to public concerns. Health, environmental, and water quality officials will review the system during the year-long process. Only then will 40 elected officials serving on the water and sanitation district boards vote on whether to proceed with any portion of the system.

The system's proposed schedule calls for design of a 13-mile pipeline between Fountain Valley and Anaheim, some new injection wells and a high-tech treatment plant to begin in 1999, with the project completed in three phases between 2003 and 2020. The system could cost from $350 million to $400 million over 20 years for the three phases.

Currently, Orange County has three sources of water: local groundwater, the Colorado River, and the State Water Project. With north and central Orange County projected to grow by one million people over the next two decades, officials expect the cost of water to rise with increased demand, in part because water purchased from outside agencies is becoming less available and more costly.

An independent rate study is part of the Groundwater Replenishment System's environmental review and the impact on water rates would be a factor in any decision to proceed -- or not to proceed -- with the system. Replenishing Orange County's groundwater basin might be the most cost-effective solution.

"This project would tap the latest and most advanced technology available to provide a reliable water supply," said Director Anthony. "This high-tech process simply would speed up the methods used by nature to recycle our water supply.

Many people are not aware of the natural cycle of water reuse or that they already may drink some reclaimed water that has been blended into drinking water supplies in a variety of ways. Water reuse has and is being accomplished safely in many water-short areas throughout the country. In Orange County and other communities, reclaimed water is injected into seawater intrusion barriers, where it blends with the groundwater. This water is then pumped out for use in homes and businesses. Orange County Water District's Water Factory 21 has done this successfully for 25 years. Reclaimed water has been used to recharge the groundwater basin in areas of Los Angeles County and many other communities for decades.

Currently, approximately 200 upstream communities discharge treated wastewater into the Colorado River, a major source of water purchased for Southern California. Similarly, Riverside County communities discharge to the Santa Ana River which currently recharges the Orange County groundwater basin.



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