After four years of drought, we have hope for some relief. There's an approximately 95 percent chance that a strong El Niño will continue through winter 2015-16, potentially bringing heavy rain to Southern California, according to the Climate Prediction Center (CPC).

The Orange County Water District (OCWD; the District) has done an excellent job as steward of our groundwater supply, navigating us through some recent tough times. The basin provides about 70 percent of the water for 2.4 million people in north and central Orange County. Its available storage area is currently only 20 percent full—still within normal levels, but the basin needs to be refilled. OCWD is preparing to capture as much stormwater as possible from the Santa Ana River (SAR) to help off-set the depletion of the groundwater basin.

One of the District's original directives when it was created in 1933 was to protect Orange County's water rights of Santa Ana River flows. OCWD's management of SAR water begins far upstream in the San Bernardino Mountains and an area behind Prado Dam in Riverside County. That region behind Prado Dam is key to catching and holding as much stormwater as possible and the District has partners who will help it do so.

The United States Army Corps of Engineers (Corps) is responsible for providing flood risk management on the Santa Ana River and owns and operates the Prado Dam. The Corps and OCWD have been working together for many years on water conservation programs to conditionally store stormwater behind the dam.

Based on a Memorandum of Agreement, the Corps temporarily impounds water behind Prado Dam to specific water surface elevations. From September to February, the Corps will store water to elevation 498 feet (up to 3 billion gallons), and to elevation 505 feet (up to 7 billion gallons) the remainder of the year.

In recent years, OCWD has been working even more closely with the Corps to increase these water surface elevations so that additional stormwater can be captured at Prado Dam and recharged into the Orange County Groundwater Basin. OCWD is planning to utilize an additional 10,000 acre-feet of storage capacity at Prado Dam for this winter, and successive winters. This will help Orange County recover from the drought if above average rainfall does indeed occur.

During the flood season, OCWD and staff in the Corps' Reservoir Regulation section, collaborate, sometimes on a daily basis. They coordinate releases from the dam at rates consistent with the primary purpose of the dam for flood risk management, but which also allow OCWD to divert the supply into recharge facilities downstream. OCWD uses inflatable rubber dams to divert the water into our recharge facilities. Slow and steady storms are optimal for capture and release.

OCWD is currently supporting legislation (S. 1894) to update the Corps' weather forecasting manuals to improve dam reservoir operations and a bill (H.R. 813) that would aid in storing additional water at Prado Dam through modernizing weather and runoff forecasting.

You might be interested in attending or reviewing the November 6 WACO (Water Advisory Committee of Orange County) meeting that will discuss this very topic. You can access it at www.youtube.com/orangecountywater. The meeting will take place at 7:30 a.m. in the OCWD Boardroom located at 18700 Ward St., Fountain Valley, CA 92708.

One El Niño will not completely solve the problems produced by a four-year drought and the increased needs for water as populations and businesses grow.

OCWD has recharged and maintained the groundwater basin at safe levels while more than doubling the basin's annual yield over more than 80 years. The Corps' operation of Prado Dam provides significant water supply benefits to Orange County. Its current collaboration with the the District to capture additional stormwater will substantially aid OCWD in maintaining "basin balance" over the long term.