Water Resources Research
CIWR's research focuses on using systems approaches to address water management challenges. We work with collaborators across California's universities and the University of California Cooperative Extension on research projects. Recent projects by CIWR and collaborators include topics of:
- Water policy and planning
- Water resource systems analysis
- Urban water management
- Agricultural water management
- Research communications
- Disaster management
- Landscape management
Examples of current and past projects are listed below.
California Wastewater Needs Assessment
NEW: Phase 1B Final Report on the Baseline Survey of Community Wastewater Needs
CIWR is part of a collaborative team that is developing a first-of-its-kind assessment of water-related sanitation needs in California. Led by UCLA's Luskin Center for Innovation, the project will collect information and develop criteria to create a statewide framework to prioritize funding for sanitation systems in California especially in disadvantaged, severely disadvantaged, and vulnerable communities.
As part of Phase 1 of the project, CIWR led a Baseline Assessment of Community Sanitation Needs. We conducted a survey of more than 150 researchers, policymakers, communities members, and NGOs to understand current needs and areas of concern for wastewater access. The final report for the baseline survey. was published in July 2025. Through 2026, CIWR is conducting a field campaign to visit areas experiencing wastewater challenges.
All available reports for the project are available through UCLA.
Project Lead: Greg Pierce, UCLA Luskin Center for Innovation.
Project Team: UCLA Luskin Center for Innovation, Office of Water Programs at Sacramento State, CIWR @ UC ANR, University of Massachusetts Amherst
CIWR Project Team: Erika Cassio Madrazo, Sam Sandoval Solis (ANR PI), Erik Porse, Riley Currey.
Project Support: California State Water Resources Control Board
Urban Water Use Efficiency and Conservation
CIWR conducts research and extension to understand and improve efforts for urban water use efficiency and conservation in California. Our work has developed models and analytical methods to evaluate benefits and impacts of water use efficiency. We have integrated demand projections into water resource models and our work has supported statewide evaluations to establish the "Making Conservation a Way of Life" regulations through Assembly Bill 1668 and Senate Bill 606 (AB 1668-SB 606) and Senate Bill 1157 focused on indoor water use.
The studies have incorporated: end use modeling, urban landscape characterization, indoor and outdoor water use demand estimation, economic evaluations of water conservation and supply-side management solutions, models to assess effects of demand changes on wastewater generation and treatment.
Our work has resulted in publications analyzing water conservation rebates, effects of lower flows on wastewater management, and methods for demand forecasting.
Project Team: Erik Porse, Rachel Shellabarger, Hope Hauptman, Camilo Salcedo
Collaborators: UCLA, UC Merced, OWP at Sacramento State, UC Riverside
Adoption Patterns of Nitrogen Use Efficiency Practices
As part of the Nitrogen and Irrigation Initiative and in collaboration with UC Riverside, we are analyzing data on nitrogen use applications and adopted best management practices from the Irrigated Lands Regulatory Program (ILRP). Results of work from the Kings River Water Quality Coalition area indicate that many growers have adopted multiple nitrogen use practices, with 26% of fields utilizing six practices and 24% using five. Such bundling may provide growers with more flexibility in managing nitrogen applications. But further research is needed to evaluate the effect of various nitrogen management practices on fertilizer use and water quality effects.
Publications:
Divya Prakash Erik Porse, Mehdi Nemati, Rachel Shellabarger and Ariel Dinar, Adoption patterns of on-farm nutrient management practices and nitrogen application rates in California’s Central Valley. California Agriculture (Forthcoming).
Project Team: Erik Porse, Rachel Shellabarger, Divya Prakash, Mehdi Nemati (UC Riverside), and Ariel Dinar (UC Riverside)
Immersive Modeling for the Colorado River Basin
Colorado River management in the 21st Century faces severe challenges. Through a project led by Utah State University (PI David Rosenberg), we conduct immersive and participatory modeling sessions for Colorado River scenario planning. Through sessions, small groups of managers and water users use online models to make decisions for Colorado River management and see effects of assumptions for inflows, diversions, and conservation.
The project is funded by the Cooperative Institute for Research to Operations in Hydrology, University of Alabama (2025-2027) and we have published studies on results of immersive modeling, the value of water accounts for Colorado River users, and the need to model more extreme inflow scenarios for future planning.
Project Lead: David Rosenberg, Utah State University
CIWR Team: Erik Porse, Michael Jaquez
Project Support: Cooperative Institute for Research to Operations in Hydrology, University of Alabama
Drought and Water System Finances
Water agencies need to to develop adequate funding sources to meet the needs of customers. Even though drought is known to affect water system operations, few studies have evaluated the effects of drought on water utility finances.
Using data from multiple sources, we evaluated the effects of drought on water utility finances for over 200 urban water agencies in California. In these systems, statistical modeling indicates that drought has a statistically significant but small impact on metrics of financial performance, with drought reducing some financial indicators. However, long-term trends in water bills and affordability overshadow any effects of drought. Thus, while many water agencies in California have adopted retail rate structures- coupled with supply and demand management strategies- to manage drought, long-term costs of these actions are increasingly felt by ratepayers.
Presentations:
Hope Hauptman, Erik Porse, and Riley Curey. Effects of Drought on Water Utility Finances. Water Finance and Management Conference. August 5, 2025. Phoenix, AZ.
Project Team: Erik Porse, Hope Hauptman, Riley Currey
Artes: Urban Water Systems Analysis in Los Angeles
In California's Mediterranean climate, cities must develop infrastructure and programs to manage seasonal and annual changes in precipitation. While many urban areas in California built huge infrastructure systems to import distant sources of water, cities also rely on local sources of water such as groundwater and stormwater capture, and water reuse. These offer ways to increase the portion of demand met by local sources.
The model simulates flows through all of these systems across hundreds of agencies to evaluate when and how changes in expectations for imported water availability affect supply and operations throughout LA County.
Artes was developed at UCLA's California Center for Sustainable Communities as part of projects to understand future water management in Southern California. The model has been used in 11 peer-reviewed studies.
The data and code associated with Artes are publicly-available. From 2016-2022, data and code were published on Github. Starting in 2022, the model is available through Hydroshare.
A Storymap published by UCLA's California Center for Sustainable Communities provides context on current water management in LA County and opportunities for transitioning to future regimes less reliant on imported water.
Porse, E. (2022). Artes: Modeling Water Resources Management in Los Angeles, HydroShare, https://doi.org/10.4211/hs.c2a8bb7e07b3409995c90a86120b2a9f
In collaboration with UCLA's Luskin Center for Innovation, CIWR developed a research and policy agenda to support water quality improvements through better wildfire management.
To address the recent emergence of wildfire-caused drinking water contamination, the researched asked a group of interdisciplinary and cross-sector participants to provide input and review on a research and policy agenda for how California can more proactively address the ways in which wildfire is increasingly putting water supply systems at risk. Workshop sessions were focused on four different research and policy issues and related questions at the intersection of wildfire events and water supply provision. The report summarizes findings from the outreach and sessions.
Project Team: CIWR and UCLA Luskin Center for Innovation
Regression Modeling for Urban Water Demand in California
Resilience planning for water management in California requires advanced analysis and data integration. Water demand forecasting can help water planners understand future water needs and develop plans for infrastructure investments, capital improvements, and demand management programs. In cities, regression modeling is a popular method to understand future operations. We used statistical modeling to understand drivers of demand for over 400 urban water supply agencies in California. The modeling used standardized data from self-reported sources for agencies across the state. The demand models served as the basis of the first detailed study in literature of the effects of the COVID-19 pandemic on urban water demand in 2020.
Porse, E. (2021). Urban Water Demand Regression Modeling for California Water Suppliers, HydroShare, https://doi.org/10.4211/hs.f70cefe684b746c6b37dd4ca056a6b34