The Orange County Water District (OCWD), in collaboration with the U.S. Army Corps of Engineers (USACE), announces the approval of a minor deviation to the Water Control Plan at Prado Dam, effective February 28, 2025. This five-year deviation represents a milestone in OCWD’s ongoing efforts to bolster the drinking water supply for 2.5 million residents through innovative stormwater capture strategies.
Denis Bilodeau, P.E., President of OCWD, underscored the importance of this approval, stating, "This is a significant achievement in our longstanding efforts to enhance the Orange County Groundwater Basin. By raising the water storage levels at Prado Dam, we are capturing more Santa Ana River stormwater and enhancing our community’s drinking water reserves in a sustainable and efficient way."
OCWD has partnered with USACE since 1995 to store water from the Santa Ana River at Prado Dam. The approved deviation allows for higher water storage levels, temporarily raising it to 508 feet above mean sea level, with potential future increases to 510 or 512 feet. This adjustment will allow for the capture of an additional two billion gallons of stormwater, which is enough water to supply 48,000 people and save $6 million in imported water costs.
The approval of the deviation will be further enhanced by the complete implementation of Forecast-Informed Reservoir Operations (FIRO) at Prado Dam, an initiative led by OCWD and the USACE
"This deviation highlights our commitment to responsible water resource management,” said Timothy Fairbank, P.E., chief of the Hydrology and Hydraulics Branch, U.S. Army Corps of Engineers’ Los Angeles District. “Working with the OCWD, we are dedicated to implementing innovative strategies that reduce our reliance on imported water, while maintaining flood-risk management to maintain public safety."
“I was glad to write to the administration in support of this project and am pleased that the Corps has decided to implement the deviation at Prado Dam, which enables the Orange County Water District to capture more local water. This will be crucial to streamline decision-making and enhance water resource management in California,” said Rep. Young Kim.
The approval of the deviation will be further enhanced by the complete implementation of Forecast-Informed Reservoir Operations (FIRO) at Prado Dam, an initiative led by OCWD and the USACE, supported by the Center for Western Weather and Water Extremes (CW3E) at Scripps Institution of Oceanography. After successful testing, FIRO has demonstrated enhanced capabilities for more accurately tracking atmospheric rivers, thereby improving the decision support process to maximize stormwater capture. Along with the approved deviation, this improvement has the potential to yield an additional 6,000 acre-feet of water annually. Additionally, CW3E will continue to refine the AI models that support FIRO. Over the next five years, the goal is to formally integrate FIRO into a decision-making process for water management, which will be documented in the water control manual, and to support achieving a higher permanent elevation for water storage. This project is poised to become the largest of its kind in Southern California and the second largest in the state.
