Emergency $600 mil to Groundwater Recharge

Los Angeles Department of Water and Power plans to spend $600 million to capture rainwater and send it underground into the massive San Fernando Valley Groundwater Basin to eventually be used as drinking water

The Los Angeles Department of Water and Power may spend hundreds of millions of dollars in the next 20 years to capture rainwater and send it underground into the massive San Fernando Valley Groundwater Basin to eventually be used as drinking water.

But that groundwater basin is home to one of the largest Superfund contamination sites in the U.S., the remnant of aerospace and other industry that once spilled chemicals throughout the region. About half of the Valley’s wells are typically inoperable because of the pollution.

As city officials finalize their plan to capture storm runoff, the other half of the equation — cleaning up the basin — is still very much a work in progress. Boosting local water supply has become a city priority, as the cost of importing water from Northern California keeps rising and the Sierra Nevada snowpack is increasingly unreliable.

In the next two years, DWP leaders hope to get approved environmental documents for a roughly $600 million water treatment facility in North Hollywood. Along with capturing more storm runoff and recycling more water, the plant would enable the city to use four times as much water as it typically pumps from the Valley. City officials are pushing to meet an expected 2017 application deadline for matching state funding from the Proposition 1 water bond.

“The whole treatment plant is critical to our local water supply plans,” said Marty Adams, DWP deputy senior assistant general manager, on the phone Friday from Sacramento.

In a typical year, the department pumps between 20,000 and 40,000 acre-feet of water from the Valley aquifer, Adams said — enough to supply twice as many homes or fill the Rose Bowl 150 times.

During the drought, the city has been pumping about double that amount from Valley wells, though the pace is unsustainable because pollution levels are rising, Adams said. With a treatment plant, the agency hopes to generate about 125,000 acre-feet annually from the basin.

Department maps of the Valley show multicolored blobs — chemical plumes in an underground water mass stretching from Tujunga to Glendale. Officials have detected high levels of trichloroethylene, tetrachloroethylene, nitrates and chromium in the basin, along with other potentially dangerous contaminants. Chemical solvents were widely used in aerospace and defense manufacturing, machinery degreasing, dry-cleaning and metal plating.

The federal Environmental Protection Agency and other regulators have been working to clean Valley water since the early 1980s, but identifying polluters and making them pay for facilities is a long and arduous process, and some smaller treatment plants have been built over the decades.

With the drought persisting, the cost of water rising and the state funds available, DWP officials are not waiting for polluters to make it right. The city is planning to pump and treat the water, instead of cleaning it before pumping. Meanwhile, the EPA is working with polluters to remediate some specific chemicals in the basin, Adams said.

“That is a relatively large change in the approach to dealing with the pollution,” said Mike Antos, director of the Center for Urban Water Resilience at Cal State Northridge.

More water will likely be coming in contact with the chemicals in coming years, making the large treatment plant critical. In the next two decades, an additional 114,000 acre-feet of stormwater runoff per year could be captured and directed into the basin. And that’s if nearly all components of the department’s Stormwater Capture Master Plan are fully implemented — an outside chance, DWP officials say.

Last week the DWP presented the final plan for public comments, and the department’s civilian oversight board is expected to approve it next month. Each stormwater project would also have to be individually approved. On the high side, the projects in the plan could cost more than $200 million, based on rough cost estimates.

Officials are also working on a $400 million water recycling facility in the Sepulveda Basin that would treat sewer effluent to a high-quality level and then pump or drain the water into the groundwater supply.

With these and other projects, the city plans to refill the basin, hopefully ensuring more stable drinking water. The aquifer can accommodate more than 400,000 acre-feet of additional water, department officials say. But before the city can use much of the water, it needs to build the treatment plant.

“It will absolutely have to happen,” Adams said. “Otherwise we would be totally dependent on imported water.”

Source: DailyNews

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