Downpours Yield 33 Billion Gallons of Captured Stormwater in L.A. County

County officials hope reclamation efforts will help the region reduce its dependence on imported water supplies.

1 minute read

January 19, 2023, 12:00 PM PST

By Diana Ionescu @aworkoffiction


View of Los Angeles River at Glendale Narrows segment with tree and overpass

The Los Angeles River swelled after heavy rains in early January. | Gerry Matthews / Los Angeles River

Los Angeles County captured 33 billion gallons of stormwater from the recent rains that drenched California, an amount that “could supply 816,000 people with water for a year,” reports Carlos Granda for ABC7. As Granda explains, “The county Public Works Department operates 14 major dams and 620 miles of rivers and flood control channels.”

One way the county collects rainwater during storms is through a series of ‘Valley Rubber Dams’ on the San Gabriel River, which can be inflated to hold water when needed. Water is then distributed to spreading facilities designed to let water soak into the earth to replenish groundwater supplies. “Approximately 98% of stormwater runoff collected from the San Gabriel River and Rio Hondo Channel is conserved, according to officials.”

Local officials plan to boost stormwater retention and use more local water supplies to reduce dependence on imported water. Southern California has historically drawn water from the state’s Owens Valley, the Colorado River, and other sources such as Mono Lake, where a conservation nonprofit recently requested a suspension of water diversion to Los Angeles to protect the lake’s critical Califoprnia gull habitat.

Tuesday, January 17, 2023 in ABC7

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Cover CM Credits, Earn Certificates, Push Your Career Forward

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

June 11, 2025 - Diana Ionescu

Metrorail train pulling into newly opened subterranean station in Washington, D.C. with crowd on platform taking photos.

Congressman Proposes Bill to Rename DC Metro “Trump Train”

The Make Autorail Great Again Act would withhold federal funding to the system until the Washington Metropolitan Area Transit Authority (WMATA), rebrands as the Washington Metropolitan Authority for Greater Access (WMAGA).

June 2, 2025 - The Hill

Large crowd on street in San Francisco, California during Oktoberfest festival.

The Simple Legislative Tool Transforming Vacant Downtowns

In California, Michigan and Georgia, an easy win is bringing dollars — and delight — back to city centers.

June 2, 2025 - Robbie Silver

Color-coded map of labor & delivery departments and losses in United States.

The States Losing Rural Delivery Rooms at an Alarming Pace

In some states, as few as 9% of rural hospitals still deliver babies. As a result, rising pre-term births, no adequate pre-term care and harrowing close calls are a growing reality.

10 seconds ago - Maine Morning Star

Street scene in Kathmandu, Nepal with yellow minibuses and other traffic.

The Small South Asian Republic Going all in on EVs

Thanks to one simple policy change less than five years ago, 65% of new cars in this Himalayan country are now electric.

2 hours ago - Fast Company

Bike lane in Washington D.C. protected by low concrete barriers.

DC Backpedals on Bike Lane Protection, Swaps Barriers for Paint

Citing aesthetic concerns, the city is removing the concrete barriers and flexposts that once separated Arizona Avenue cyclists from motor vehicles.

4 hours ago - The Washington Post