North Coast

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.

Priorities for California’s Water -- Stewarding the Wet Years

Public Policy Institute of California (PPIC) | November 2nd, 2023

The 2023 water year provided a case study of California’s increasingly volatile climate, with large swings between wet and dry conditions both within and between years.

The 2023 water year provided a case study of California’s increasingly volatile climate, with large swings between wet and dry conditions both within and between years. It highlighted our need to better navigate multiple imperatives: storing more water during intense wet periods to build water supply reliability, protecting communities and infrastructure against the threat of increasingly damaging floods, and taking better advantage of wet years to improve the health of freshwater ecosystems and native fish and wildlife.

Priorities for California’s Water: Advancing Research During Uncertain Times

Public Policy Institute of California (PPIC) | November 12th, 2025

In California, research underpins all water-related activity. It is vital for coping with too much water, too little water, and rapid changes in hydrology. Whether you ar

In California, research underpins all water-related activity. It is vital for coping with too much water, too little water, and rapid changes in hydrology. Whether you are a farmer managing the precise application of water to your crops, a utility providing clean drinking water supplies to your community, or a restorationist trying to heal a damaged wetland, your actions rely upon decades of applied research that guides your actions and measures your success.  The same reliance on research applies if you are developing policies to reduce the price of water, increase its reliability, regulate its usage, and reduce hazards from floods. None of this works without a vast research enterprise that is regularly updating the science and technology we use to manage water, prepare for the future, inform the public, and address new problems as they arise. 

Priorities for California’s Water: Are We Ready for Climate Change?

Public Policy Institute of California (PPIC) | November 12th, 2024

California faces many immediate challenges around water management, but as the record-breaking heat of 2024 makes clear, temperatures are rising—and Californians are co

California faces many immediate challenges around water management, but as the record-breaking heat of 2024 makes clear, temperatures are rising—and Californians are contending with the consequences. In a PPIC poll earlier this year, residents named climate change, forest fires and wildfires, and water supply and drought as the most important environmental issues facing the state. 

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. 

Procedures to evaluate sea-level change: impacts, responses, and adaptation

U.S. Army Corps of Engineers (USACE) | June 30th, 2014

Projected U.S. drought extremes through the twenty-first century with vapor pressure deficit

Nature Portfolio (Springer Nature) | May 21st, 2022

Global warming is expected to enhance drought extremes in the United States throughout the twenty-first century. Projecting these changes can be complex in regions with

Global warming is expected to enhance drought extremes in the United States throughout the twenty-first century. Projecting these changes can be complex in regions with large variability in atmospheric and soil moisture on small spatial scales. Vapor Pressure Deficit (VPD) is a valuable measure of evaporative demand as moisture moves from the surface into the atmosphere and a dynamic measure of drought. Here, VPD is used to identify short-term drought with the Standardized VPD Drought Index (SVDI); and used to characterize future extreme droughts using grid-dependent stationary and non-stationary generalized extreme value (GEV) models, and a random sampling technique is developed to quantify multimodel uncertainties. The GEV analysis was performed with projections using the Weather Research and Forecasting model, downscaled from three Global Climate Models based on the Representative Concentration Pathway 8.5 for present, mid-century and late century. Results show the VPD based index (SVDI) accurately identifies the timing and magnitude short-term droughts, and extreme VPD is increasing across the United States and by the end of the twenty first century. The number of days VPD is above 9 kPa increases by 10 days along California’s coastline, 30–40 days in the northwest and Midwest, and 100 days in California’s Central Valley.

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

Quantifying the Relationship Between Atmospheric River Origin Conditions and Landfall Temperature

American Geophysical Union (AGU) | October 11th, 2022

The temperature of landfalling atmospheric rivers (ARs) has direct implications for regional water resources. Compared to cool ARs, warm ARs can result in more surface ru

The temperature of landfalling atmospheric rivers (ARs) has direct implications for regional water resources. Compared to cool ARs, warm ARs can result in more surface runoff and flooding, less water availability via low snow accumulations and enhanced snowmelt, and greater challenges for storm forecasting and reservoir operations. Based on case studies, ARs with subtropical origin locations and warm origin conditions are assumed to be associated with warmer landfall temperatures—though, to date, this has not yet been demonstrated systematically. We analyze North Pacific ARs that made landfall along the West Coast of North America from 1980 to 2017. We find that ARs originating over the subtropical Pacific Ocean near Hawaii (“Pineapple Express”-type ARs) are indeed 1.5°C warmer and 2 kg/m2 moister in winter than ARs originating elsewhere. We extend this analysis for the full study population of ARs by quantifying AR origin conditions, including the spatial distribution of origin temperature, moisture content, and integrated vapor transport (IVT). We use fixed effects multivariate regression to quantify the relative influence of the origin conditions on landfall temperature. Our regression models show that AR origins with lower latitudes, longer AR lifetimes, and stronger IVT are associated with warmer landfall temperatures and that ARs that start warm generally stay warm. We also find that the phase of the El Niño/Southern Oscillation does not exhibit a consistent relationship with AR landfall temperature. Overall, our results partially affirm—yet also complicate—common assumptions about the role of different origin conditions in landfalling AR temperature.

Rapid decline of California’s native inland fishes: a status assessment

University of California, Davis (UC Davis) | November 1st, 2010

Degradation of freshwater ecosystems is a global crisis best understood through intensive study of well-studied regional faunas. A quantitative protocol was used

Degradation of freshwater ecosystems is a global crisis best understood through intensive study of well-studied regional faunas. A quantitative protocol was used to determine conservation status of all 129 freshwater fishes native to California. Seven (5%) are extinct; 34 (26%) qualified for listing as endangered or threatened species; 32 (25%) were rated as imperiled, qualifying as California Species of Special Concern, with potential for listing; 34 (26%) rated being on a watch list and 22 (17%) were found to be relatively secure. Of 31 species officially listed under federal and state endangered species acts, 17 (55%) clearly qualified for listing under our criteria and 12 (39%) were rated as species of special concern. Conversely, of 34 extant species with the lowest ratings under our criteria, only 17 (50%) were officially listed. Climate change, area occupied and anthropogenic threats had the largest negative impact on status. Of the 15 categories of anthropogenic threats analyzed, those most likely to diminish status were alien species, agriculture and dams. Overall, 83% of California’s freshwater fishes are extinct, endangered, or in decline, a 16% increase since 1995 and a 21% increase since 1989. The decline seen in California’s inland fishes is probably typical of declines in areas that are less well documented, indicating a strong need for better methods of conservation of freshwater ecosystems.