Systems Analysis and Modeling of Local Water Supplies in Los Angeles

Project Summary

Many water agencies in Los Angeles County are investing in local water resources, including recycled water and stormwater capture and use. But new tools are needed to support investments in new infrastructure. These tools must rethink past expectations of water use, supply sources, and the financial accounting that pays for water systems. As part of a multi-campus research effort spanning a decade, a comprehensive analysis was undertaken to quantify the potential for local water reliance in metropolitan L.A. and assess tradeoffs in water conservation, supply sources, landscape changes, and economics. The effort integrated new and existing models with emerging research to create a comprehensive and open-source repository for understanding paths to water sustainability in Los Angeles. The project has analyzed needed governance innovations to achieve local water reliance across L.A. County, including the needed for more broadly shared rights to pumping and storage in regional groundwater basins.

Research Team

Stephanie Pincetl
Institute of the Environment and Sustainability, Physical Sciences

Erik Porse
Institute of the Environment and Sustainability,  Physical Sciences

Kathryn Mika
Institute of the Environment and Sustainability,  Physical Sciences

Mark Gold
Institute of the Environment and Sustainability, Physical Sciences

Kimberly Manago
Civil and Environmental Engineering, Colorado School of Mines

Terri Hogue
Civil and Environmental Engineering, Colorado School of Mines

Elizaveta Litvak
Biology, University of Utah

Diane Pataki
Biology, University of Utah

Progress and Results

An open-source model (Artes) was developed to simulate regional water management activities, understand countywide trends in water use, and identify promising options for promoting local reliance. In creating the model, the team collected and integrated data from multiple sources, including assessments of outdoor water use by trees and plants based on field experiments, costs and energy intensities of water flows throughout the county, regional hydrology, and infrastructure operations. Artes has been used to assess integrated urban water management strategies and tradeoffs, including:

  • Identifying baseline water use across indoor and outdoor needs for over one-hundred water agencies in metropolitnan Los Angeles that serve 10 million residents. Results found that a regional water use target of 80-100 gallons per capita per day would support reductions of as much as 70 percent of historic imported water supplies.  
  • Assessing economic feasibility of alternative supply options, which incorporates project rising cost of imported water.  Already, many local sources of water are cheaper. Benefit cost assessments of future supply options should compare annualized costs across new and existing sources that incorporate likely rate increases of imported water. Increasing stormwater capture and use, an important goal for enhancing groundwater recharge in the region's critical basins, would likely reduce downstream flows in rivers, illustrating tradeoffs in regional planning goals.
  • Quantifying energy use effects of reducing imported water supplies in a comprehensive, bottom-up assessment of energy-for-water needs at the metropolitan scale.
  • Effects of stormwater capture and use on urban streamflows across L.A. County.  Imported water sources are significantly more energy intensive than local supplies, even when considering new treatment and pumping requirements. 

Outreach

  • The LA Water Hub, and web platform for visualizing and understanding water management in Los Angeles. The LA Water Hub also includes links to policy fact sheets and presentations of research results. 
  • Blog pieces for the California Water Blog on sustainable groundwater management, Los Angeles water management, and urban water conservation.
  • Presentations on all of the above topics, presented at the Environment and Water Resources International Congress (2017, 2018), American Water Resources Association, Biennial Symposium on Managed Aquifer Recharge (2018), California Water Environmental Modeling Forum, the International Environmental Modeling and Software Symposium (2018), and other venues.  

Project photo of the Los Angeles Aquifer

Category

Funding Source

The National Science Foundation's Water, Sustainability, and Climate Program; the John Randolph Haynes and Dora Haynes Foundation

Award Year

2013