As Californians tally up the damage from recent storms, some take stock of the rainwater collected by cisterns, wells, underground ponds and other catchment systems, much of which has been built in recent years to relieve a bog down of decades of drought.

The accumulation of rainwater is one of the few positive aspects of the downpours which have killed at least 20 people, collapsed hillsides and damaged thousands of homes.

Los Angeles County, which has 88 cities and 10 million people, collected enough stormwater to supply about 800,000 people for a year, county public works department director Mark Pestrella said.

In the four years since Californians passed a bill to spend hundreds of millions of dollars a year building small and medium-sized stormwater infrastructure projects, experts say progress has been gradual, but not insignificant.

In Santa Monica, a new project has captured nearly 7,600 cubic meters (2 million gallons) of runoff that, once treated, is used for domestic needs, irrigation or pumped into the city’s aquifer. city.

Sunny Wang, the city’s water resources manager, said the project will ultimately save an average of about 151,000 cubic meters (40 million gallons) per year.

The vast majority of stormwater that falls on California cities ends up draining into the ocean. In Los Angeles, a complex system of dams and paved flood control canals diverts water from roads and buildings to the sea as quickly as possible. The century-old infrastructure was designed to prevent urban flooding.

From the Los Angeles River alone — with a concrete-lined channel beginning in the San Fernando Valley and ending in the ocean at Long Beach — 58,000 acre-feet (71.54 million cubic meters) of stormwater has washed up at sea during recent storms, said Kerjon Lee, spokesman for the Los Angeles County Department of Public Works. This equates to approximately 20% of Nevada’s Colorado River allocation each year.

“It’s a large volume that we capture, but it’s a small percentage of the watershed,” Wang said. “Billions of gallons of stormwater enter Santa Monica Bay each year, so 40 million (gallons in savings) sounds like a lot, but it’s just a first step toward more investment we need. make “.

Santa Monica says its sustainable water infrastructure project is the first of its kind in California. Most people probably don’t know it exists.

Hidden under a newly paved parking lot next to a county courthouse, the sewage treatment plant filters and purifies sewage as well as runoff to produce water so potable it exceeds state and federal regulations.

County officials say the water saved is important, not only to bolster the water supply, but also to prevent pollutants picked up by that stormwater from flowing into the Pacific Ocean.

Pestrella, the county’s public works chief, said the stormwater harvested in recent weeks could be enough to prevent the Southern California Metropolitan Water District, which serves Los Angeles, San Diego and other major urban centers, from imposing stricter water restrictions in the upcoming spring and summer. .

To escape the drought, Pestrella added, “we need at least three years of this type of rain.”

Most of Los Angeles’ water comes not from its own basin, but from a vast storage and supply system that carries snowmelt from the Sierra Nevada mountain range in northern La California and the Colorado River to the east.

County officials say the government has invested $400 million in state efforts to boost local water supplies by capturing rainwater from more than 100, mostly new, regional projects over the past of the last two years. Officials said they expect projects in Southern California to be completed within eight years and could provide enough water for an additional 500,000 people in Los Angeles County.

The county’s long-term goal, over the next 30 years, is to collect 300,000 acre-feet (370 million cubic meters) of stormwater, enough to serve up to 900,000 homes annually.

Bruce Reznik, executive director of the environmental nonprofit Los Angeles Waterkeeper, called the expansion of the city’s stormwater harvesting projects a “race against time” due to drought and springs. overexploited water in the state. He said a slow authorization process is partly to blame.

“We are starting to make progress, but obviously we have to do better,” added Reznik. “In recent years, people have become more and more serious.”

In the Willowbrook area of ​​south Los Angeles, Earvin “Magic” Johnson Park was created on a former oil storage field that was later partially converted into a housing project. Now the 104-acre (42-hectare) park with two lakes, playground, exercise equipment, and community center also collects runoff.

The renovation was completed in 2021. For most people who walk around the lakes, the park is just a pleasant place to stroll. Ducks swim across the lake while Canada geese honk from an islet.

“It’s safe, quite peaceful and just beautiful,” said Barbara Washington Prudhomme, a retired postal service.

She was unaware of the park’s other benefits, such as the existence of a small structure near the lake that recycles dirty runoff captured by storm drains that would otherwise have flowed into the sea. This water is now used to refill the lake or water the lawn as needed.

When she learned that the park’s design allowed it to capture and divert up to 4 million gallons (15,000 cubic meters) per storm, she was impressed.

“It’s a good system if it works,” he said.

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Naishadham reported from Washington, D.C.

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