L.A. betting that stormwater can help ease California’s drought

Five years of drought have struck different parts of California unevenly.

Cities with multiple sources of water have weathered the crisis relatively well, even after important reservoirs have hit bottom.

But residents of some small towns in the San Joaquin Valley and northern California, who depend on a single source of water, have had their daily routines upended when one important well or creek has run dry.

If California’s water emergency has taught providers anything, it is that they must they must diversify their supply — or face dire consequences.

Los Angeles took a major step in that direction earlier this week, when officials, brandishing shiny shovels, broke ground on a project there that they say will play a key role in bolstering the region’s water supply and protecting against future droughts.

The spreading grounds, a 150-acre tract of porous soil in the northeast San Fernando Valley, capture stormwater that falls from the sky or runs off from nearby mountains and hills, and allows the water to filter into a vast aquifer that can be drawn down when the resource is in short supply.

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Under the $29-million expansion plan launched Monday, officials said the groundwater recharge facility will double in capacity by 2018, helping wean Angelenos off increasingly expensive and unreliable imported water.

“There’s a giant lake underneath us,” David Wright, the newly appointed general manager of the Los Angeles Department of Water and Power said Monday at the site. “We need to fill it up.”

Currently, the Tujunga Spreading Grounds can capture and store about 8,000 acre-feet of water a year, officials said. That figure is expected to double to 16,000 acre-feet, or 5 billion gallons — enough water to supply 48,000 Los Angeles households each year.

Capturing more stormwater at the spreading grounds helps ensure that the precious commodity does not run off into the Pacific Ocean. The project will also provide new open space and a walking path for nearby residents, officials said.

“This is a huge priority for me,” said Mayor Eric Garcetti, who has developed a series of water-related goals for the region as part of his Sustainable City Plan.

DWP customers, spurred on by state drought regulations, are already well on their way to meeting one of the plan’s goals: cutting per-capita water usage by 20% compared with fiscal year 2013-2014.

But five years of drought have also forced water providers statewide to invest in ways to bolster their local supply. By increasing the use of recycled wastewater, capturing more stormwater and even turning to ocean water desalination, the argument goes, districts can protect their customers from future water shortages.

For example, the San Diego County Water Authority has agreed to purchase water from a newly-minted desalination plant in Carlsbad, in part to reduce its reliance on imported supplies.

Further north, the Orange County Water District has expanded its groundwater replenishment system, such that it can now produce an additional 30 million gallons of water per day.

The Metropolitan Water District of Southern California even offers a financial incentive for water agencies to develop their local supplies.

Garcetti wants Los Angeles to reduce its purchase of imported water by 50% by 2025 and obtain half of its water locally by 2035.

Currently, only 15% of the city’s water comes from Los Angeles, the mayor said. About 57% is imported and purchased from the Metropolitan Water District of Southern California, a DWP spokeswoman said.

Specifically, Garcetti has called on Los Angeles to capture 150,000 acre-feet of stormwater annually; the spreading ground expansion project is expected to help get the city about 88% of the way there by 2035.

“The severity of the current drought and the challenges of climate change, population growth and an unreliable imported water supply require the combined attention and effort of the entire region,” said Gail Farber, director of the L.A. County Department of Public Works, which operates the Tujunga Spreading Grounds. “The city of Los Angeles has been a fantastic partner in this regard.”

matt.stevens@latimes.com

Twitter: @ByMattStevens

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UPDATES:

Friday 11:11 a.m.: This article was updated with additional details.

This article was originally published at 5 a.m.