Orange County Water District Successfully Captures Rainfall From Tropical Storm Hilary To Bolster Local Drinking Water Supplies

With the arrival of Tropical Storm Hilary, the Orange County Water District (OCWD; the District) maximized water supply operations to capture 2.56 inches of rain, ensuring not a drop was lost to the ocean, and increase its water storage behind Prado Dam to more than 3.4 billion gallons of water.

OCWD was prepared to take full advantage of stormwater capture due to decades of sound planning, regional partnerships, and investments in water infrastructure. Located in the northern part of the county lies its managed aquifer recharge system where a series of rubber dams, pumps and percolation ponds work to get water into the Orange County Groundwater Basin (Basin). The Basin is a vital resource managed by OCWD which supplies 85% of the water for 2.5 million people.

Additionally, a historic cooperative agreement with the United States Army Corps of Engineers (Corps) has continued to allow OCWD to store water behind Prado Dam. This pool of water can be strategically held back and released at rates that the District can capture through its recharge system, eventually flowing into the Basin and increasing local drinking water supplies. The water storage currently held behind the dam is enough to serve 100,000 people for one year and is valued at an estimated $12.6M, equivalent to the cost of imported water, reinforcing the need to invest in local water supplies.

"Capturing stormwater has been part of the District’s diverse water supply portfolio for decades," said OCWD Board President Cathy Green. "Thanks to the incredible partnership with the Corps, we have continued to increase stormwater capture behind Prado Dam, which has proven to be an economical and effective solution to the region’s water challenges without compromising the safety of the dam."

To further enhance stormwater capture, OCWD is testing Forecast Informed Reservoir Operations (FIRO) at Prado Dam. With the support of the Scripps Institution of Oceanography at the University of California, San Diego and the Corps, FIRO aims to develop improved weather forecasting, including storms and atmospheric rivers, and ultimately update the Corps’ control manuals to increase water storage levels behind Prado Dam.

“OCWD is well positioned to maximize water supply for the region, during wet or dry times,” Green added. “Our long history of active water management and investments have ensured a sustainable groundwater basin that will serve generations to come.”

About The Orange County Water District
The Orange County Water District manages the local groundwater basin that provides 85% of the water supply for 19 cities and retail water districts in north and central Orange County, serving 2.5 million people. Guided by its commitment to sound planning and investment, high standards for water reliability, exceptional water quality, environmental stewardship, sound financial management, and transparency, OCWD has proactively implemented initiatives to protect and increase local water supplies. OCWD replenishes the basin, prevents seawater intrusion, and protects Orange County’s rights to Santa Ana River water. For more information, visit www.ocwd.com.