Water Agencies to Capture More Stormwater Below Seven Oaks Dam
Capturing more stormwater will help the region get through extended droughts, like the one currently gripping the region.
SAN BERNARDINO, Calif., May 24, 2019 — Inland Empire water agencies rely on local rainfall for roughly 75 percent of their water supply, and import the rest from the State Water Project and other sources.
But there is still a lot of water that flows into the ocean each year. Local water agencies are developing the capability to capture and store more water, about twice the historical amount, to help the region brace for extended droughts, like the current one that is in its 20th year.
San Bernardino Valley Municipal Water District has partnered with Western Municipal Water District, San Bernardino Valley Water Conservation District and Riverside Public Utilities on the first phase of new stormwater capture facilities downstream of Seven Oaks Dam in Mentone.
“When completed, these facilities will divert up to about a quarter of a million gallons of water every minute and up to 80,000 acre-feet of stormwater in a single year,” said T. Milford Harrison, Valley District’s president. “This will more than double the stormwater capture and recharge capabilities downstream from the dam.”
Capturing and storing more of our local stormwater runoff is also financially prudent. Water flows to the area and is filtered as it is put into the ground at no cost.
The first phase of this project, the Enhanced Recharge Project, includes water intake improvements as well as construction of a 700-foot-long by 140-foot wide sedimentation basin just downstream from Seven Oaks Dam. The sedimentation basin allows the sediment to settle out of the water before it moves downstream to existing and proposed groundwater recharge basins to increase water storage.
In addition to building the massive sedimentation basin, water agencies have installed an eight-foot-diameter pipeline to transport the sediment-free water to existing recharge basins and to the Foothill Pipeline near Highland, so that it could be delivered to recharge basins throughout the San Bernardino Valley.
“Capturing more of our local stormwater is good water management,” said Bob Tincher, Valley District’s deputy general manager for resources. “Given the environmental
pumping restrictions on the State Water Project, we are continually looking for new water supplies to help us make it through extended droughts like the one we are in now.”
The additional diversion of Santa Ana River water below the Seven Oaks Dam is made by possible by the water rights permits that Valley District and Western Municipal Water District obtained from the California Department of Water Resources in 2010.
Future phases of the Enhanced Recharge Project are expected to begin in 2020 pending completion of the Upper Santa Ana Wash Land Management and Habitat Conservation Plan. The next phase will include construction of new recharge basins and canals to facilitate recharge of additional captured stormwater. Future phase include improvements to the Cuttle Weir and intake structure in order to make the entire diversion system more robust, especially during high water flows.
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