Preparing for New Risks: Addressing Climate Change in California’s Urban Water Management Plans

California Department of Water Resources (DWR) | June 20th, 2013

Urban Water Management Plans (UWMPs) are a central component of California’s efforts to assure reliable water supplies, particularly during drought conditions that are

Urban Water Management Plans (UWMPs) are a central component of California’s efforts to assure reliable water supplies, particularly during drought conditions that are frequently experienced in the state. Prepared by water suppliers every five years, UWMPs include supply and demand projections for the next 20 years, and describe strategies to assure adequate supplies during average, single-­year, and multi-­year drought conditions. UWMPs also contain plans to implement a 20% reduction in per capita urban water use by the year 2020, as required under the Water Conservation Act of 2009 (SBX7-­7). Climate change is introducing new risks in water planning, such as increasing temperatures, reduced snowpack, changing precipitation patterns, and accelerating sea level rise, which are already being observed in the state. It is increasingly important for water suppliers to consider how these trends are impacting water supply, demand, and drought patterns. Water suppliers can also make important contributions to reducing greenhouse gas emissions (GHGs), through energy savings from water conservation as well as other measures. In its guidance to water suppliers for preparing 2010 UWMPs, the California Department of Water Resources (DWR) included an optional section focused on consideration of climate change impacts and GHG emissions. This study assesses how water suppliers have incorporated these factors into their 2010 plans. Drawing upon a sample of 2010 UWMPs, it examines the nature and extent of climate change discussion and analysis, and assesses how climate change risks have been incorporated into water supply and demand projections. The report also provides recommendations for how DWR could improve its guidance for 2015 UWMPs to support water suppliers in addressing climate change. All public and investor-­owned utilities serving 3,000 customers or supplying at least 3,000 acre-­feet of water annually are required to submit an Urban Water Management Plan to DWR every five years. Of the approximately 400 agencies submitting UWMPs, most are relatively small, with 90% serving less than 300,000 people, and 40% serving less than 50,000.  Most are public entities, but some are private companies, including three investor-­owned utilities with multiple service areas across the state. Large and small water suppliers tend to differ in their access to resources for planning and analysis of issues such as climate change. For many small suppliers, UWMP preparation serves as their primary long-­term planning process. Suppliers also vary in the nature of their vulnerability to drought and the impacts of climate change. Larger suppliers usually have multiple sources of supply, while small suppliers are more likely to rely on a single source, especially groundwater. These small utilities are less likely to have relationships with other suppliers, thereby reducing their options for coping with severe droughts. This study is based on an analysis of 49 individually submitted UWMPs, seven regional UWMPs, and UWMPs from three investor-­owned utilities with multiple service areas across the state. The sample was stratified so that it represents water suppliers of all sizes. It includes all large suppliers (serving 300,000 or more customers), and 10% of medium-­sized and small suppliers (serving 50,000 – 300,000 and less than 50,000 customers, respectively). Each UWMP was analyzed for its content related to climate change, and classified according to the degree and focus of discussion. This report is also informed by informal consultations with representatives of water supply agencies of different sizes.

Pricing Practices in the Electricity Sector to Promote Conservation and Efficiency: Lessons for the Water Sector

Pacific Institute | September 11th, 2013

Because water utilities are dependent on the sale of water to recoup costs, reduced sales can result in deficits – and per capita water demand in California has been st

Because water utilities are dependent on the sale of water to recoup costs, reduced sales can result in deficits – and per capita water demand in California has been stagnant or decreasing for the past several decades. Over the coming years, California municipal water utilities are required to reduce water use by 20%. Thus, the “new normal” or an era of declining demand and rising costs is a trend that is likely to continue. Water utilities can learn from a number of electricity pricing practices to help adapt to this “new normal” while staying fiscally solvent and providing fair prices. “California’s energy sector has implemented many pricing policies that seek to balance a commitment to energy conservation with utility financial health,” said Kristina Donnelly of the Pacific Institute, lead author of the report. “Both water and energy utilities are coping with similar financial challenges related to demand reductions and stand to benefit from a greater exchange of information and lessons learned.” In order to understand how some of these practices might be relevant to the water sector, the Pacific Institute examined a range of electricity pricing practices and policies that California electric utilities use to remain financially stable even when per capita demand is decreasing. The paper, Pricing Practices in the Electricity Sector to Promote Conservation and Efficiency: Lessons for the Water Sector, helps inform discussion at the local, regional, and state level about water pricing in light of recent and future reductions in water demand.

Priorities for California’s Water

Public Policy Institute of California (PPIC) | November 14th, 2022

This report considers the state of water in California: What changes are we seeing now, and what should we expect in the near future? Then it examines how these climate s

This report considers the state of water in California: What changes are we seeing now, and what should we expect in the near future? Then it examines how these climate shifts will impact urban and rural communities, agriculture, and the environment. Finally, it explores wet-year strategies that will help Californians get through the dry years.

Prioritizing Candidate Green Infrastructure Sites within the City of Ukiah: A Demonstration of the Site Locator Tool of GreenPlan-IT. Report prepared for the City of Ukiah Department of Public Works under Supplemental Environmental Project # R1-018-0024

San Francisco Estuary Institute (SFEI) | April 1st, 2019

Green infrastructure (GI), also known as Low Impact Development (LID), has emerged as an integral aspect of multi-benefit, watershed approaches to address concerns about

Green infrastructure (GI), also known as Low Impact Development (LID), has emerged as an integral aspect of multi-benefit, watershed approaches to address concerns about stormwater quality and quantity in an urban environment. When carefully applied, GI installations, such as rain gardens, tree-well planters, and permeable pavement, can be cost-effective, resilient ways to manage storm water at its source with measurable, cumulative environmental and community benefits. 

Public Review Draft Report to the Legislature on the Results of the Indoor Residential Water Use Study

Publisher not available | May 11th, 2021

Water planning has always been important for urban retail water suppliers (Suppliers) but is even more critical today, as development progresses and California grapples w

Water planning has always been important for urban retail water suppliers (Suppliers) but is even more critical today, as development progresses and California grapples with frequent droughts and expected long-term climate impacts. Prior to the adoption of the Urban Water Management Planning (UWMP) Act in 1983, there were no specific requirements that mandated urban water suppliers to conduct long-term water resources planning. While many Suppliers did conduct long-term water planning, those that did not were more vulnerable to supply disruptions during dry periods and catastrophic events. Urban water management planning is needed at the local level because only local Suppliers have the knowledge and ability to tailor their planning to their unique conditions and involve their local community in the planning effort. Click here for the DWR press release

Pure Water Southern California

Metropolitan Water District of Southern California (MWD) | March 29th, 2024

Quantifying the Multiplier Effect of Southern California’s Turf Removal Rebate Program with Time-Series Aerial Imagery

American Water Resources Association (AWRA) | December 30th, 2020

From 2014 to 2016, water agencies in Southern California provided more than $350 million in rebates to owners who converted their turf to drought-tolerant landscaping. In

From 2014 to 2016, water agencies in Southern California provided more than $350 million in rebates to owners who converted their turf to drought-tolerant landscaping. In order to provide a fuller understanding of the water savings of this program, this study establishes that there was a behavioral contagion, or a multiplier effect, from rebate participants in the program. An imagery-based, time-series analysis of 20 Southern California neighborhoods from 2012 to 2018 was performed to detect what parcels converted their lawns without a rebate and how they were spatially correlated with rebate participants. This correlation was then used on almost 55,000 rebate participants to estimate the multiplier benefits for the entire program at 132%. For every 100 rebate participants, the multiplier effect helped contribute to an additional 132 parcels to convert to drought-tolerant landscaping. This methodology was compared with a previous study in the Irvine Ranch Water District providing similar results. This study provides the Metropolitan Water District of Southern California a better understanding of the water savings per rebate dollar of the Turf Removal Rebate Program as well as providing a robust approach for cities or water agencies to estimate the multiplier effect of their turf rebate programs.

Recommendations to the State Water Resources Control Board Pursuant to California Water Code Section 10609

California Department of Water Resources (DWR) | September 29th, 2022

The Department of Water Resources (DWR) is pleased to provide the following recommendations developed in response to the 2018 Legislation (Senate Bill 606 [Hertzberg] and

The Department of Water Resources (DWR) is pleased to provide the following recommendations developed in response to the 2018 Legislation (Senate Bill 606 [Hertzberg] and Assembly Bill 1668 [Friedman]) enacted in support of “Making Water Conservation a California Way of Life.” The Legislation included provisions for advancing urban water use efficiency through developing and implementing various water use efficiency standards, variances for unique uses of water, and commercial, industrial, and institutional (CII) performance measures, among other requirements. Full reports detailing our methods, technical analyses, studies, public input, and recommendations will follow. These recommendations for long-term urban water use efficiency reflect technical considerations, public input, and the imperative to continue California’s progress in urban efficient use of water for future generations. If adopted DWR's recommendations on outdoor residential and CII water use on landscapes with dedicated irrigation meters, combined with the indoor residential water use standard recommendations submitted to the Legislature jointly by DWR and State Water Resources Control Board (State Water Board), pursuant to Water Code 10609.4 (b)(1), would result in expected long-term water savings of approximately 450,000 acre-feet per year starting in 2030 – considering 2019 population and 2017-2019 water use data, the water savings are enough to supply about 1.6 million homes or 4.7 million residents for both indoor and outdoor annual water needs.

Reimagining Water Infrastructure in a Changing California

American Water Resources Association (AWRA) | April 15th, 2023

For much of the 20th century, California’s water supply strategy has relied on building large reservoirs and conveyance systems to store and divert surface water and dr

For much of the 20th century, California’s water supply strategy has relied on building large reservoirs and conveyance systems to store and divert surface water and drilling ever deeper wells to tap declining aquifers. This approach has brought many benefits but has also come at great social, economic, and environmental costs. Moreover, these traditional water supplies are tapped out. Even in wet years, the state’s major rivers are overallocated and major aquifers severely overdrafted. Dry years intensify these issues. Persistent water challenges, the severe drought, and the intensifying effects of climate change highlight the vulnerability of California’s water systems and the need for new approaches.

Residential End Uses of Water, Version 2: Executive Report

Water Research Foundation (WRF) | April 14th, 2016

It is essential for water providers and the urban water supply industry to have a detailed understanding of how water is usedin residential settings. While water

It is essential for water providers and the urban water supply industry to have a detailed understanding of how water is usedin residential settings. While water use in homes was studied as early as the 1940s, interest intensified after the Energy Policy Act of 1992, which sought to improve energy and water efficiency. This Act established maximum flow rates for new residential toilets, showerheads, and faucets. Later federal regulations included clothes washers. Water efficiency in homes has also been encouraged by programs like EPA’s WaterSense. Until now, the most significant residential end use study conducted in North America was the Water Research Foundation’s 1999 report, Residential End Uses of Water (REU1999) (Mayer et al. 1999). WRF’s newreport, Residential End Uses of Water, Version 2 (REU2016) (DeOreo et al. 2016), provides an updated and expanded assessment of water use. It includes more varied study site locations, hot water usage data, more detailed landscape analysis, and additional water rate analysis. The new study identifies variations in water use by each fixture or appliance, providing detailed information and data on changes since the REU1999 study. Looking to the future, the study’s research evaluates conservation potential, and includes predictive models to forecast residential demand. The decline in water use across the residential sector, even as populations increase, poses new challenges for water utilities. Information on single family home water consumption is significant for utility rate and revenue projections, capital planning (water supply and infrastructure needs), daily operations to provide water, water efficiency programs, and more.