California storm water system installed to collect rainwater

LOS ANGELES (AP) — As Californians tally damage from the recent storms, others are looking at rainwater captured by reservoirs, puddles, wells and underground reservoirs. Many of them were built in recent years to provide relief to states trapped in decades of drought.

Rainwater on the bank is a rare bright spot. Heavy rains kill at least 20 peoplecollapsed hillsides and damaged thousands of homes.

With 88 cities and a population of 10 million, Los Angeles County has collected enough water from storms to feed about 800,000 people a year, said Mark Pestrella, director of the Los Angeles County Public Works Department. .

Four years after measures were approved by Californians to invest hundreds of millions of dollars annually to build small and medium-sized infrastructure projects to harvest rainwater, experts say progress has been slow but negligible. It wasn’t.

In Santa Monica, a new water project will recover approximately 2 million gallons (7,600 cubic meters) of runoff water that, once treated, will be used for plumbing, irrigation, or pumped back into the city’s aquifer .

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

Most of the stormwater in California’s cities ends up in the ocean. In Los Angeles, an intricate system of dams and paved flood control channels directs water away from roads and buildings and into the ocean as quickly as possible. The 100-year-old infrastructure was designed to keep cities from flooding.

The concrete-lined Los Angeles River alone, which begins in the San Fernando Valley and ends in the ocean at Long Beach, pumped 58,000 acre-feet of rainwater into the ocean during recent storms.Angeles County Public Works Department. This is about 20% of the annual allotment from the Colorado River in Nevada.

“It’s a big number we’re catching, but it’s a small part of the watershed,” says Wang. “With billions of gallons of rainwater entering the Santa Monica Bay each year, 40 million may sound like a lot, but it is just the beginning of the additional investments we need. .”

Santa Monica says its sustainable water infrastructure project is the first of its kind in California. Most people hardly know it exists.

A wastewater treatment plant, hidden beneath a newly paved parking lot adjacent to the courthouse, simultaneously filters and purifies sewage and runoff, producing water that exceeds state and federal drinking water regulations.

County officials say conserving water is important not only to boost water supplies, but also to prevent pollutants picked up by rainwater from flowing into the Pacific Ocean.

Pestrera, the county’s public works chief, said the stormwater generated in the past few weeks is expected to hit the largest amount next spring in Southern California’s Metropolitan Water District, which supplies water to major population centers like Los Angeles and San Diego. said it could be enough to prevent imposing stringent water restrictions…and summer.

“We need at least three years of this kind of rain,” Pestrera added, to escape drought.

Most of Los Angeles’ water does not come from its own watershed, but from an extensive storage and distribution system that brings snowmelt water from the Sierra Nevada Mountains in northern California and the Colorado River in the east.

The government has invested $400 million in more than 100 local projects in the past two years from statewide efforts to harness rainwater to increase local water supplies, most of them new, according to county officials. was. Officials expect the project in Southern California to be completed within eight years, and said it could provide enough water for another half a million people in Los Angeles County.

The county’s long-term goal (over the next 30 years) is to collect 300,000 acre feet of harvested rainwater, enough to serve 900,000 households annually.

Bruce Reznik, executive director of the environmental nonprofit Los Angeles Waterkeeper, called scaling up rainwater harvesting projects in Los Angeles “a race against time” because of the drought and the state’s excess water resources. He said the slowness of the permitting process was partially to blame.

“We are starting to make progress, but we clearly need to improve,” said Reznik. “In the last few years, people have become more and more serious.”

Irvine “Magic” Johnson Park in the Willowbrook neighborhood of south Los Angeles is located in a former oil depot that was later partially developed into a housing project. The 104-acre park, which now features two lakes, a playground, exercise equipment, and a community center, also collects runoff from storms.

The renovation will be completed in 2021. For the vast majority of people who take walks around the lake, the park is the perfect place for a walk. Ducks circle the lake in pairs and Canadian geese crow from small islands.

“It’s safe, it’s so peaceful, it’s just beautiful,” said Barbara Washington Prudhomme, a retired postal worker.

She was unaware of the park’s other benefits. A small structure near the lake recycles dirty stormwater runoff from storm drains that would have drained into the ocean, using it to fill the lake or irrigate the grass when needed. That’s it.

When she heard about a park design that could capture and divert up to 4 million gallons (about 15,000 cubic meters) of water per storm, she was impressed.

“If it works, it’s a good system,” she said.


Naishadham reported from Washington DC


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