L.A. County Captures Record Amount of Stormwater to Boost Local Water Supplies

Heavy rains this winter and spring have brought a deluge of water to Los Angeles County, but instead of letting it all flow into the ocean, officials have managed to capture and store a significant amount of that stormwater. According to Mark Pestrella, director of L.A. County Public Works, the county has snared an estimated 295,000 acre-feet of water since last October, which is equivalent to 96.3 billion gallons. This amount of water could supply about 2.4 million people for a year, nearly one-fourth of the county’s population.

The success in capturing and storing this stormwater can be attributed to investments totaling more than $1 billion since 2001. Some of the funds have gone towards raising dams and increasing the capacity of spreading grounds, where water is sent into basins and then percolates underground into aquifers. Additionally, more than $1 billion has been spent on removing sediment from reservoirs to ensure their water-catching capacity isn’t diminished.

The L.A. County Flood Control District, funded by property taxes, has been a significant contributor to these efforts. Moreover, the Safe, Clean Water Program, established after county voters passed Measure W in 2018, has also provided funding for stormwater-catching infrastructure.

Despite the substantial amount of runoff captured since October, the county’s facilities took in even more water during the major storms over the previous 12 months. The runoff has collected behind 14 county dams and flowed downstream to spreading grounds that recharge groundwater at 27 county-operated facilities. Much of the water collected over the past winter is now stored underground.

Capturing rainwater not only adds to the supplies of local cities but is also a more cost-effective alternative to importing water from Northern California or the Colorado River. Storm runoff that isn’t captured flows into the Pacific Ocean via various waterways.

The county’s water plan, adopted in December, aims to capture more stormwater and reduce reliance on imported water to make the region more resilient to the effects of climate change. By 2045, the plan calls for L.A. County to become 80% reliant on local water supplies through capturing more stormwater, recycling wastewater, and boosting conservation efforts.

Officials at the L.A. Department of Water and Power have also been actively involved in capturing stormwater, with investments exceeding $130 million in stormwater infrastructure projects since 2008. City officials plan to further boost local water supplies by investing in more stormwater capture, recycling wastewater, and cleaning up contaminated groundwater.

Overall, the efforts to capture and store stormwater represent a significant step forward in ensuring a more sustainable water supply for Los Angeles County. Environmental advocates have supported these initiatives, emphasizing the importance of harnessing more runoff, recycling water, and reducing reliance on external water sources. With continued investment in infrastructure and conservation efforts, the county is on track to become more resilient to the challenges posed by climate change and water scarcity.