Opinion: Reservoirs Are Full, but California Still Needs New Water Infrastructure

For the third year in a row, California has significantly more than average amounts of water stored in reservoirs across the state. This is enough water to carry us through about three years of major drought — which we all know is coming. Local and regional water providers continue to develop new projects to capture and store excess water when it is available, and the governor and the state Department of Water Resources are now actively supporting two key projects.

On the positive side, the Department of Water Resources recently announced an increase in State Water Project allocation from 40% of users’ total requests to 50%. This is important locally because the Metropolitan Water District has water beyond immediate customer demand at about 40% allocation, and that extra water can be available for purchase and storage for dry years.

On the negative side, in the same April 29 press release, the Department of Water Resources stated:

“California’s water system is complex and requires real-time adjustments to balance the needs of our state’s cities and farms and the natural environment. Earlier this month, the State Water Project reduced pumping in the Sacramento-San Joaquin Delta to minimum levels to protect endangered fish species. These reductions are required as part of the operating permit for the State Water Project. Operators will likely maintain that lower rate through the end of May unless San Joaquin or Sacramento River flows increase beyond certain high-flow thresholds.

These constraints reinforce the need for California to invest in additional water supply infrastructure to provide operational flexibility. The proposed Sites Reservoir and Delta Conveyance Project would have been hugely beneficial to water supply had they been in place this season. The Delta Conveyance Project could have captured more than 167,000 acre-feet of additional water supply this winter, which would have translated to a 20% increase in current State Water Project allocation, on top of the increase announced today.”

In short, California has plenty of water — it’s just not where we need it when we need it.

On May 15, the governor put forth legislation that would streamline permitting and ensure funding for the Delta Conveyance Project. This is part of his budget proposal and has a decent chance of being approved by the Legislature.

Western Water is leading a broad coalition of water providers and users to support Senate Bill 72 by Sen. Anna Caballero, which would establish a target of 9 million acre-feet of new water supply in the state by 2040, with an additional goal to be determined by the Department of Water Resources by 2050. A similar bill passed the Legislature without a single negative vote in either house last year but was vetoed by the governor. This year’s bill looks promising in light of the administration’s support for new water infrastructure. Visit CA Water for All to learn more and find out how to participate.

Locally, your water providers have been working hard to create new infrastructure to capture and store additional storm runoff and snowmelt from our local mountains. A partnership of San Bernardino Valley Municipal Water District, Western Municipal Water District, Riverside Public Utilities and the San Bernardino Valley Water Conservation District recently celebrated the completion of a major groundwater replenishment project just below the Seven Oaks Dam on the Santa Ana River near Highland. This includes an inflatable rubber diversion dam, a sedimentation basin and nearly 400 acres of percolation basins to capture excess runoff through Seven Oaks Dam. The project can add several hundred thousand acre-feet of water per year to the San Bernardino Basin, which is presently overdrafted. Both RPU and Western Water have rights to water in this basin.

A significant new component of this effort is an advanced modeling system called Forecast-Informed Reservoir Operations, or FIRO. Seven Oaks Dam was built as a flood control facility and is not operated as a water storage facility. FIRO can help dam operators use the facility not just for flood control, but to store excess runoff and release it at a rate that allows more water to be captured and infiltrated into the groundwater basin. Local water agencies have already succeeded in working with the operator of Prado Dam to increase storage and regulate releases for beneficial use while still protecting its primary flood control mission. We are optimistic that a similar arrangement can be made with Seven Oaks Dam, providing both effective flood control and the ability to put runoff to beneficial use.