Los Angeles Sustainable Water Project: Ballona Creek Watershed

November 13, 2015
The Ballona Creek Watershed.
Katie Mika

Ballona Creek Watershed is the largest watershed draining to the Santa Monica Bay.  It covers 128 square miles and is 82% developed and 61% impervious. It also includes the Ballona Creek Wetlands, which if you haven’t explored yet, you should. We also looked at the nearby Hyperion Treatment Plant, the largest LA City-owned wastewater treatment plant, and the West Basin Municipal Water District Ed C. Little Water Reclamation Facility (ELWRF) to identify opportunities for recycled water supply.

One potential local water supply in Ballona Creek watershed is increasing the volume of stormwater captured (which will also help achieve water quality standards) and infiltrating it or capturing it for on-site reuse.  Our study found a possible recharge capacity of 20,000 to 60,000 acre-feet per year (AFY). However, how much of this water could become part of our water supply depends on the hydrology, the available water rights in the groundwater basins, and the rate of implementation of Best Management Practices to address stormwater.

An additional 220,000 AFY could come from treating the current flow leaving Hyperion to drinking water quality through advanced treatment for reuse. Advanced treatment trains could be expanded at the ELWRF or added at Hyperion to enable this treatment.  However, careful study is required of upstream opportunities as well to determine where increasing this water supply is most cost-effective.

Overall, total potential local water supply in the Ballona Creek Watershed is greater than the demand. Demand is 196,000 AFY based on a population of 1.5 million and per capita water consumption of 117 gallons per capita per day compared to 240,000 to 280,000 AFY of potential supply.  For context, LADWP supplied about 600,000 AFY in 2014.  Stay tuned here for more info on moving IWM forward as we go deeper into these issues in coming months.

This study is part of a series of Sustainable LA Grand Challenge Integrated Water Management reports, including the Dominguez Channel and Machado Lake Watersheds and the Los Angeles River Watershed. These reports along with the Los Angeles City-Wide Overview report help provide a path forward for the region to reach the UCLA Sustainable LA Grand Challenge’s ambitious goal of 100% local water in L.A. County by 2050.

The research team included UCLA associate vice chancellor for environment and sustainability Mark Gold, UCLA postdoctoral scholar Katie Mika, professor Terri Hogue of the Colorado School of Mines (CSM), as well as, UCLA professor Stephanie Pincetl and Katie Radavich of CSM.