Droughts are already a reoccurring feature in California, and climate change will make water supplies even less reliable in a variety of ways. Most of the water used in the mega population centers of California, the world’s fifth-largest economy, comes from critically over-drafted groundwater supplies, or imported water reliant on snow pack that climate scientists forecast will significantly decrease over the next century.

Changes in procuring water supplies will impact not only water agencies and household water bills, but also the energy grid. To prepare for these shifts and the ever-growing population, communities across California see the need for a resilient, more locally-reliant water future. Multi-pronged strategies to achieve this include decreasing imported water demand through water conservation or local markets and increasing local water supply through water recycling and expanded capture and use of stormwater.

The Luskin Center for Innovation (LCI) conducts research to expand local water opportunities, such as through the following projects. 

Envisioning an Urban Water Market for Los Angeles County (Current project, link is to concept paper)
Researchers: Nicholas Chow, J.R. DeShazo, Brad Franklin, and Gregory Pierce

UCLA’s Sustainable LA Grand Challenge has an ambitious goal for Los Angeles County: 100 percent locally-sourced water by 2050, while enhancing ecosystem and public health. Currently, the vast majority of the region’s water is piped in from hundreds of miles away. With a grant from the UCLA Sustainable LA Grand Challenge, LCI is exploring a strategy to help the 215 community water systems in the county collaborate across systems to utilize local water.

The 215 systems vary greatly in their local water resources, including access to groundwater and aquifer storage, stormwater capture, water reuse, and complementary infrastructure. These differences will become more profound as the region reduces its reliance on imported water. Some systems will have abundant, lower-cost local water that far exceeds consumption levels. Other systems will face a scarcity of local water, and at much higher cost. This will create incentives for systems with abundant local water to develop storage capacity cost effectively. And it will create incentives for systems with scarce local water to purchase such water from their neighbors, which could justify a more integrated, regional water management strategy.

Given this logic, LCI researchers expect that that there could be significant cost and water supply benefits, to both the water sector and households, in achieving greater local water reliance through bilateral trading. The work involves:

  • assessing where additional infrastructure investments will be optimal in an urban water market;
  • identifying the institutional architecture necessary to support and regulate such a system; and
  • examining the potential value of a water market to alleviate the inequities in household water billing, in particular for disadvantaged and low-income communities.

Advanced Water Recycling and the Energy Implications (Current project)
Researchers: Nicholas Chow and J.R. DeShazo

In the face of Southern California’s expected climate variability and drought conditions, the production of recycled water could increase quickly. By reducing the distance that water travels, recycled water would also reduce the energy required to transport clean water. But there could also be energy challenges associated with expanded recycled water production.

The California Energy Commission, in concert with the U.S. Department of Energy and the U.S.-China Clean Energy Research Center, awarded LCI part of a $1.1 million grant to study the energy intensity of recycled water production. Specifically, LCI researchers analyzed advanced recycled water for direct potable reuse and found that this strategy could meet up to 57 percent of the water needs in Los Angeles County, while providing statewide energy savings. Next research steps include an analysis of the greenhouse gas emissions and economic costs embedded in these findings.

Fighting Drought with Stormwater and Green Infrastructure (Current project)
Researchers: Gregory Pierce and Kelsey Jessup

Water-scarce urban areas in California lose billions of gallons of fresh water each year as rain washes into storm drains and out to sea. A nearly $2 million grant-funded project seeks to transform University of California campuses into living laboratories that show how urban stormwater can safely augment water supplies and minimize flood risk. Through coordinated research, modeling, and engagement with university officials and regulatory agencies, the research team is developing the science, engineering, and policy innovations needed to usher in a new era of treating stormwater as a resource rather than a liability.

Gregory Pierce, associate director of research for LCI, is part of a research team comprising faculty, staff, and students from all five southern University of California (UC) campuses that received the grant from UC’s Multi-campus Research Programs and Initiatives. Their role on the larger team is to examine how universities compare to cities in terms of governance and financial capacity to invest in green infrastructure, and how to overcome barriers in capacity to enhance stormwater capture more broadly. The work includes a comparative analysis of how various cities are approaching stormwater capture and management, and why.

Turf Replacement Program Impacts on Households and Ratepayers (2016 report)
Authors: J.R. DeShazo, Kelsey Jessup, and Ali Panjwani

During a historic drought that started in 2011, the Los Angeles Department of Water and Power increased, to $1.75 per square foot, the rate that property owners could receive for replacing turf with more drought resistant landscaping. A study by LCI answered two questions: Under what conditions does participation in the turf replacement program provide financial benefits to households? And is the turf replacement program a reasonably cost-effective investment for utilities and ratepayers?

Researchers used data accumulated from 2009 until 2015, during which time the City of Los Angeles spent more than $42 million on the turf replacement program. In partnership with the Metropolitan Water District, the city issued rebates for 15 million square feet of turf, saving approximately 66,000 gallons of water a year. To assess the economics of lawn replacement from the household perspective, the report measured the impact of different rebate levels, turf replacement costs, climate zones, and future expected water pricing on household financial benefits. Rebates of $1.75 result in a payback period for typical households and ratepayers of approximately 10 years, comparable to other investments such as solar. The report also calculated the payback periods for ratepayers based on varying levels of household participation in the turf replacement program and different levels of rebates.

Graywater Reuse in the United States (2013 policy and 2015 cost-benefit analyses)
Authors of 2013 policy review published by the Water Environmental Research Journal: Zita L.T. Yu, Anditya Rahardianto, J.R. DeShazo, Michael K. Stenstrom, and Yoram Cohen
Authors of 2015 cost-benefit analysis published by the Journal of the American Water Works Association: Zita L.T. Yu, J.R. DeShazo, Michael K. Stenstrom, and Yoram Cohen

The reuse of graywater has emerged as an important sector in water reuse, especially in arid regions. Defined as domestic wastewater not originated from toilets (e.g., generated from hand-washing sinks, showers, bathtubs, and washing machines), graywater can often be reused onsite without treatment for subsurface irrigation while above-ground water reuse is often allowed only when treatment is provided.

In a study supported by LCI, researchers reviewed graywater reuse regulations and guidelines within the U.S. The policies included onsite treatment requirements, use application permits, and guidelines for graywater segregation as a separate wastewater stream. The study found that regulations in the majority of states promote safe graywater reuse but that there are also inconsistencies between plumbing codes and other regulations within and among the 50 states. Easing restrictions and new guidelines to promote development of low-cost and proven treatment technologies are needed to better promote graywater reuse.

In a related study also involving LCI, researchers performed a cost-benefit analysis of onsite graywater recycling in single-family and multifamily residences, using Los Angeles as a case study. The authors compared a low-cost, wetland treatment system with a high-cost commercial treatment system in order to evaluate cost savings. The researchers found that commercial treatment options may be economically feasible only for multi-family dwellings with high water consumption. For single-family residences, a wetland treatment system was found to be cost-effective based on the amount of non-potable water generally consumed by these households.