Scenarios of Future California Water Demand Through 2050

California Department of Water Resources (DWR) | August 14th, 2014

This paper describes the application of future scenarios for Water Plan Update 2013 (DWR 2013) to quantify future water demand for California and our 10 hydrologic region

This paper describes the application of future scenarios for Water Plan Update 2013 (DWR 2013) to quantify future water demand for California and our 10 hydrologic regions out to the year 2050. Starting with the publication of California Water Plan Update 2005 (DWR 2005), DWR has applied the concept of scenarios to describe future water management conditions. Scenarios are used to capture a broad range of uncertain factors that affect water management that are considered to be beyond the control of water managers. For Update 2013 scenarios were organized around narrative themes of growth and climate change, which were then quantified using factors about future population growth, housing densities, land use patterns, and climate.  For Updates 2005 and 2009, DWR attempted only to quantify future water demand management strategies at the hydrologic region scale. The hydrologic regions are large areas of tens of thousands square miles, too large to compute meaningful information on regional water management actions. But in parallel to the hydrologic region scale analysis as in current Update 2013, DWR has been pursuing a longer term project, to perform a more complete hydrologic analysis at the finer planning area scale. Results and analysis of planning area water management strategies is given in a separate report.  In addition to this paper, background information on the application of scenarios can be found in Chapter 5 and 6 of Update 2013. Chapter 5 provides information how scenarios are used to quantify water management uncertainty. Chapter 6 describes DWR’s efforts to effect long term improvements in data and analytical tools to support the Water Plan. 

Science and Decision Making: Water Management and Tree‐Ring Data in the Western United States

American Water Resources Association (AWRA) | October 5th, 2009

Growing populations, limited resources, and sustained drought are placing increased pressure on already over‐allocated water supplies in the western United States, prom

Growing populations, limited resources, and sustained drought are placing increased pressure on already over‐allocated water supplies in the western United States, prompting some water managers to seek out and utilize new forms of climate data in their planning efforts. One source of information that is now being considered by water resource management is extended hydrologic records from tree‐ring data. Scientists with the Western Water Assessment (WWA) have been providing reconstructions of streamflow (i.e., paleoclimate data) to water managers in Colorado and other western states (Arizona, New Mexico, and Wyoming), and presenting technical workshops explaining the applications of tree‐ring data for water management for the past eight years. Little is known, however, about what has resulted from these engagements between scientists and water managers. Using in‐depth interviews and a survey questionnaire, we attempt to address this lack of information by examining the outcomes of the interactions between WWA scientists and western water managers to better understand how paleoclimate data has been translated to water resource management. This assessment includes an analysis of what prompts water managers to seek out tree‐ring data, how paleoclimate data are utilized by water managers in both quantitative and qualitative ways, and how tree‐ring data are interpreted in the context of organization mandates and histories. We situate this study within a framework that examines the coproduction of science and policy, where scientists and resource managers collectively define and examine research and planning needs, the activities of which are embedded within wider social and political contexts. These findings have broader applications for understanding science‐policy interactions related to climate and climate change in resource management, and point to the potential benefits of reflexive interactions of scientists and decision makers.

Sea level rise and flooding of hazardous sites in marginalized communities across the United States

Nature Portfolio (Springer Nature) | November 20th, 2025

Sea level rise (SLR) increases the risk of flooding at coastal sites that use and produce hazardous substances. We assess whether socially marginalized populations in the

Sea level rise (SLR) increases the risk of flooding at coastal sites that use and produce hazardous substances. We assess whether socially marginalized populations in the United States are more likely to be impacted by projected SLR-related flooding of hazardous sites that could result in contaminant releases. We identify 5500 facilities at risk of a 1-in-100-year flood event by 2100 under a scenario of continued high greenhouse gas emissions, including coastal power plants, sewage treatment facilities, fossil fuel infrastructure, industrial facilities, and formerly used defense sites. Seven states (Louisiana, Florida, New Jersey, Texas, California, New York, and Massachusetts) account for nearly 80% of projected at-risk facilities. Controlling for population density and county, a one standard deviation increase in the proportion of linguistically isolated households, neighborhood residents identifying as Hispanic, households with incomes below twice the federal poverty line, households without a vehicle, non-voters, and renters is associated with 19-41% higher likelihood of having a site at risk of SLR-related flooding within 1 kilometer (odds ratios [95% confidence intervals]: 1.19 [1.09, 1.31], 1.22 [1.08, 1.37], 1.27 [1.16, 1.39], 1.35 [1.21-1.51], 1.36 [1.21, 1.53], and 1.41 [1.32, 1.52], respectively). Results elucidate the need for disaster planning, land-use decision-making, as well as mitigation strategies that address the inequitable hazards and potential health threats posed by SLR.

Sea level rise and the drivers of daily water levels in the Sacramento-San Joaquin Delta

Nature Portfolio (Springer Nature) | December 17th, 2023

Sea Level Rise Impacts on Wastewater Treatment Systems Along the U.S. Coasts

American Geophysical Union (AGU) | April 13th, 2018

Wastewater treatment plants are susceptible to flooding resulting from sea level rise. Previous estimates of wastewater exposure have only considered the impacts of mar

Wastewater treatment plants are susceptible to flooding resulting from sea level rise. Previous estimates of wastewater exposure have only considered the impacts of marine flooding at the local or regional scale. In this analysis, we quantify the exposure to marine flooding across the coastal United States and then consider the relative impacts of marine and groundwater flooding at the regional scale in the San Francisco Bay Area. We also estimate the number of people who may lose access to wastewater services if no actions are taken to prevent flooding at wastewater treatment plants. We find that the number of people impacted by sea level rise due to loss of wastewater services could be five times as high as previous predictions of the number of people who experience direct flooding of their homes or property. We also find that groundwater flooding poses a significant threat to wastewater plants in the San Francisco Bay region.

Sea Level Rise in California

Public Policy Institute of California (PPIC) | February 29th, 2024

Sea Level Rise Vulnerability Study for the City of Los Angeles

University of Southern California Sea Grant Program | December 31st, 2013

Climate change is expected to usher in an era of higher temperatures, increased precipitation and/or severe drought, and increased rates of sea level rise around

Climate change is expected to usher in an era of higher temperatures, increased precipitation and/or severe drought, and increased rates of sea level rise around the world. According to the National Research Council (NRC), global sea level has risen at an increasing rate since the late 19th / early 20th Century, when global temperatures first started to rise. Climate researchers believe sea level rise will drive storm surge and wave run-up higher than current conditions, thereby causing more extensive and frequent coastal, storm-driven flooding. Sea level rise in Los Angeles is expected to match global projections over the next century with anincrease of 0.1 - 0.6 meters (m), or 0.3 - 2.0 feet (ft), from 2000 - 2050 and 0.4 - 1.7 m (or 1.3 - 5.6 ft) from 2000 - 2100 (NRC 2012). Tides, wave-driven run-up, and storm surge play critical roles in coastal flooding in Southern California, especially when big wave storms occur at or near peak high tides. Sea level rise will potentially exacerbate the damage from these events.

Sea Level Variations of the United States 1854–2006

National Oceanic and Atmospheric Administration (NOAA) | December 19th, 2009

The United States National Water Level Network (NWLON) was established in the 19th Century to ensure the Nation’s nautical charts, shoreline maps, and elevations relat

The United States National Water Level Network (NWLON) was established in the 19th Century to ensure the Nation’s nautical charts, shoreline maps, and elevations relative to homes, levees, and other coastal infrastructure were accurately referenced to sea level. In support of this mission, NOAA’s Center for Operational Oceanographic Products and Services and its predecessors have determined sea level for the United States since the mid 19th Century. While climate change was not a concern during the mid-1800s, the accurate determination of sea level was critical for navigation and marine boundary determination. To meet these important requirements, technology, procedures, and processes were developed to the highest scientific and engineering standards. At the turn of the 20th Century it was realized that there was a need to account for a rise in sea level and the first National Tidal Datum Epoch was established. Today this Epoch is updated every 20 to 25 years. The Supreme Court recognized these standards and procedures in the landmark 1936 case of Borax, Ltd v. City of Los Angeles when legally defining sea level. Due to those initial efforts and the continued dedication of those charged with the responsibility for monitoring sea level for the United States, we can accurately determine relative (local) mean sea level along the Nation’s coastline today. These observations also play an important role in monitoring change in global sea level. As we monitor change in sea level into the 21st Century, the statement made by Alexander Dallas Bache, the Second Superintendent of the Coast Survey, is as relevant today as when it was stated more than 150 years ago, “It seems a very simple task to make correct tidal observations; but, in all my experience, I have found no observations which require such constant care and attention” (1854). Michael Szabados, Director, Center for Operational Oceanographic Products and Services

Sea-level rise and coastal groundwater inundation and shoaling at select sites in California, USA

Journal of Hydrology: Regional Studies (Elsevier) | January 5th, 2016

Study region: The study region spans coastal California, USA, and focuses on three primary sites: Arcata, Stinson Beach, and Malibu Lagoon. Study focus: 1m and 2m sea-

Study region: The study region spans coastal California, USA, and focuses on three primary sites: Arcata, Stinson Beach, and Malibu Lagoon. Study focus: 1m and 2m sea-level rise (SLR) projections were used to assess vulnerability to SLR-driven groundwater emergence and shoaling at select low-lying, coastal sites in California. Separate and combined inundation scenarios for SLR and groundwater emergence were developed using digital elevation models of study site topography and groundwater surfaces constructed from well data or published groundwater level contours. New hydrological insights for the region: SLR impacts are a serious concern in coastal California which has a long (∼1800km) and populous coastline. Information on the possible importance of SLR-driven groundwater inundation in California is limited. In this study,the potential for SLR-driven groundwater inundation at three sites (Arcata, Stinson Beach,and Malibu Lagoon) was investigated under 1m and 2m SLR scenarios. These sites provide insight into the vulnerability of Northern California coastal plains, coastal developments built on beach sand or sand spits, and developed areas around coastal lagoons associated with seasonal streams and berms. Northern California coastal plains with abundant shallow groundwater likely will see significant and widespread groundwater emergence, while impacts along the much drier central and southern California coast may be less severe due to the absence of shallow groundwater in many areas. Vulnerability analysis is hampered by the lack of data on shallow coastal aquifers, which commonly are not studied because they are not suitable for domestic or agricultural use. Shallow saline aquifers may be present in many areas along coastal California, which would dramatically increase vulnerability to SLR-driven groundwater emergence and shoaling. Improved understanding of the extent and response of California coastal aquifers to SLR will help in preparing for mitigation and adaptation.

Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future

National Academy of Sciences (NAS) | December 13th, 2012