May 4, 2023

Part 1: What’s up with LA’s Water Supply? 

For over 20 years, California has cycled from extreme wet to extreme dry conditions. Exacerbated by the climate crisis, these seasons have become even more dramatic. This year, the 2022-2023 wet season pulled California out of extreme drought following a series of 12 atmospheric rivers. These short and concentrated storms—while providing a much needed boost to our water supply—are not enough to end the drought because our infrastructure is ill-equipped to capture such massive rainfalls.  

Los Angeles county relies heavily on imported water, an increasingly contentious issue. The Colorado River Basin, a huge supplier of water across the western states, is currently grappling with the effects of the regions worst drought in 1,200 years. The new proposals by the federal government to address the declining water levels allude to a future where California will receive less water from the river. As such, we will need to turn towards alternative local sources of water in order to meet current demands. 

 How local water sources can meet the water needs for Angelenos 

On a dry day in Los Angeles County, nearly 100 million gallons of urban runoff moves through our storm drain system. That flow increases dramatically on rainy days—up to 10 billion gallons per day. Collectively, an estimated 100 billion gallons of water a year is lost to our stormdrain system – about a quarter of the water used annually by Angelenos. That water is a lost opportunity—if captured, it could be infiltrated into aquifers, used as irrigation, or support habitat. This year, precipitation levels were nearly 200% of average, meaning much more water went down the drain.  In a region that imports the majority of its water, more can be done to localize our water.  

In 2018, the growing concerns over the future of our water supply led voters in Los Angeles county to approve Measure W, creating the Safe Clean Water Program (SCWP), to provide funding to increase stormwater capture using green infrastructure to recharge local groundwater basins and enhance local water supplies through multi-benefit projects. These projects seek to capture and treat stormwater to serve three distinct purposes: to reduce runoff pollution, enhance local water supply, and green local communities.  

The East LA Sustainable Median Stormwater Capture Project is one of the few completed SCWP projects. Located in the unincorporated area of East Los Angeles, this project transformed the medians that were bare grass and incorporated infiltration wells under the surface to divert and infiltrate urban and stormwater runoff from the existing storm drain.  

The East LA Sustainable Median Stormwater Capture Project is a great example of a multi-benefit stormwater project. Above ground, this project incorporated bioswales, planted drought tolerant landscaping and over 300 trees, and installed jogging paths, exercise equipment, picnic tables/benches, and educational signage. And, crucially, over the course of a year it will infiltrate ~1160 acre feet of water (~378 M gallons).

How we need to think about stormwater 

After a parade of atmospheric rivers dumped tens of billions of gallons of water on LA County in a record breaking wet-season, the potential of stormwater capture is front and center. As is, LA’s infrastructure lacks the capacity to capture excess stormwater. As extreme weather becomes the new normal, we need to rethink how we look at LA’s existing water infrastructure. By looking at where our water comes from, we can use the lessons from this historic wet season to bolster our waterways through green stormwater capture solutions and set LA County on a path toward water-resiliency.

Next Up 

As a part of this series, LA Waterkeeper will provide an localized view on the state of our county’s water supply, analyze our current water infrastructure, and highlight projects that showcase what is possible in a water-resilient LA.