The Essential Role of Local Context in Shaping Risk and Risk Reduction Strategies for Snowmelt-Dependent Irrigated Agriculture

American Geophysical Union (AGU) | June 11th, 2024

The estimated impact of California’s urban water conservation mandate on electricity consumption and greenhouse gas emissions

Environmental Research Letters (IOP) | January 12th, 2018

In April 2015, the Governor of California mandated a 25% statewide reduction in water consumption (relative to 2013 levels) by urban water suppliers. The more tha

In April 2015, the Governor of California mandated a 25% statewide reduction in water consumption (relative to 2013 levels) by urban water suppliers. The more than 400 public water agencies affected by the regulation were also required to report monthly progress towards the conservation goal to the State Water Resources Control Board. This paper uses the reported data to assess how the water utilities have responded to this mandate and to estimate the electricity savings and greenhouse gas (GHG) emissions reductions associated with reduced operation of urban water infrastructure systems. The results show that California succeeded in saving 524,000 million gallons (MG) of water (a 24.5% decrease relative to the 2013 baseline) over the mandate period, which translates into 1830 GWh total electricity savings, and a GHG emissions reduction of 521,000 metric tonnes of carbon dioxide equivalents (MT CO2e). For comparison, the total electricity savings linked to water conservation are approximately 11% greater than the savings achieved by the investor-owned electricity utilities’ efficiency programs for roughly the same time period, and the GHG savings represent the equivalent of taking about 111 000 cars off the road for a year. These indirect, large-scale electricity and GHG savings were achieved at costs that were competitive with existing programs that target electricity and GHG savings directly and independently. Finally, given the breadth of the results produced, we built a companion website, called H2Open, to this research effort that allows users to view and explore the data and results across scales, from individual water utilities to the statewide summary.

The Extraordinary California Drought of 2013/2014: Character, Context, and The Role of Climate Change

American Meteorological Society (AMS) | September 30th, 2014

Nearly the entire state of California experienced extremely dry conditions during 2013 (Fig. 2.1a). Statewide, 12-month accumulated precipitation was less than 34% of

Nearly the entire state of California experienced extremely dry conditions during 2013 (Fig. 2.1a). Statewide, 12-month accumulated precipitation was less than 34% of average (Fig. 2.1b), leading to a wide range of impacts. In early 2014, state and federal water agencies announced that agricultural water users in the Central Valley would receive no irrigation water during 2014 (DWR 2014; USBR 2014), and that a number of smaller communities throughout California could run out of water entirely within a 90-day window (USDA 2014a). Low rainfall, unusually warm temperatures, and stable atmospheric conditions affected the health of fisheries and other ecosystems (CDFW 2014), created highly unusual mid-winter wildfire risk (CAL FIRE 2014), and caused exceptionally poor air quality (BAAQMD 2014). Such impacts ultimately resulted in the declaration of a state-level “drought emergency” and the federal designation of all 58 California counties as “natural disaster areas” (USDA 2014b). *From Explaining Extreme Events of 2013 from a Climate Perspective, Bull. Amer. Meteor. Soc., 95 (9), S1–S96.

The Fifth National Climate Assessment: Report in Brief

U.S. Global Change Research Program | November 14th, 2023

The frontiers of water and sanitation

Nature Portfolio (Springer Nature) | January 19th, 2023

The way in which human society uses water is continuously evolving. The present challenges related to clean water availability require the development of sustainable tech

The way in which human society uses water is continuously evolving. The present challenges related to clean water availability require the development of sustainable technologies and infrastructure. Furthermore, a stronger and wider appreciation of water inequalities and injustice demand an adequate transformation of water governance at local and global scale. We have asked nine experts in various sectors of water-related research to share their views on how water and sanitation science, technology and governance must evolve to meet the requirements of a healthier relationship between water and society.

The Governance Gap: Climate Adaptation and Sea-Level Rise in the San Francisco Bay Area

University of California, Davis (UC Davis) | June 27th, 2017

This report summarizes the results of an extensive study of governance for climate adaptation and sea-level rise in the San Francisco Bay Area (SF Bay Area), wh

This report summarizes the results of an extensive study of governance for climate adaptation and sea-level rise in the San Francisco Bay Area (SF Bay Area), where the concept of sea-level rise adaptation also includes coastal flooding from high tides and extreme storm events. We focus on the “governance gap” that exists between the problem of sea-level rise and the implementation of adaptation solutions that increase resilience. We take a broad view on governance as the set of institutional arrangements, governmental authorities, and public stakeholders who collectively plan and implement adaptation activities, including identifying funding strategies and the agreeing on the information basis for decision making. While most stakeholders recognize the risk of sea-level rise and other climate impacts, and have good ideas about potential on-the-ground solutions, realizing these solutions requires overcoming a series of governance challenges. All of these governance challenges are barriers to stakeholder cooperation at multiple geographic levels—local, regional, state, and federal. There are many different governmental and non-governmental actors facing the same sea-level rise problem (in “the same boat”), and coordination is required to have them “row in the same direction.” The imperative for multi-level cooperation becomes more poignant as the science on sea-level rise continues to advance, and considers the possibilities of higher average levels of sea-level rise and rapid and extreme sea-level rise due to accelerated melting of the Antarctic ice sheet. This report summarizes the major challenges, identifies the menu of possible solutions, and develops some specific recommendations on the next steps needed to remedy the governance gap and enhance the adaptive capacity of the SF Bay Area. The governance analysis is a component of the larger UC Davis/Berkeley research project called Resilience of Infrastructure as Seas Rise (RISeR), See Figure 1, which is funded by National Science Foundation to analyze the interactions between sea-level rise adaptation, transportation infrastructure, and governance in the SF Bay Area. The governance analysis was conducted in Fall 2016-Winter 2017, and is based on a qualitative case study that combines in-person interviews, focus groups, document analysis, and content analysis of interview responses. The draft report was made available to study participants in Spring 2017, along with two webinars for receiving feedback. Participants included leaders of governmental and non-governmental organizations across the SF Bay Area region. The research focused mainly on sea-level rise and coastal flooding, but also linked to broader issues of climate adaptation when appropriate. Focus groups deliberated on the best possible solutions to solving the identified governance challenges. Respondents identified the overarching governance challenge as the imperative for multi-level cooperation among all sea-level rise adaptation stakeholders. Sea-level rise adaptation entails interdependencies, where the vulnerabilities and adaptation decisions of local actors impose regional costs and benefits. While regional cooperation is beginning to emerge, most stakeholders see a critical need for shared learning, coordination and planning. The recommendations provided in this report are intended to accelerate the processes of learning and cooperation needed to address the increasingly urgent problem of sea-level rise and coastal flooding.

The growing importance of oceanic moisture sources for continental precipitation

Nature Portfolio (Springer Nature) | July 24th, 2020

The precipitation that falls on the continents defines the extent and nature of terrestrial ecosystems and human activity in them, all of which are adapted to a

The precipitation that falls on the continents defines the extent and nature of terrestrial ecosystems and human activity in them, all of which are adapted to and maintained by present-day precipitation. In essence, precipitation is supplied by moisture that either comes directly from the ocean, or is subsequently recycled from the continents themselves. Both the processes that control evaporation and the main mechanisms of moisture transport clearly differ between the ocean and the continent, thus within the context of a changing climate, it may be expected that the relationship between precipitation of oceanic and terrestrial origin varies globally and regionally, as will the influence of these two basic components of total precipitation on global and regional precipitation trends, especially in tropical regions. We describe an approach based on a Lagrangian technique for estimating the precipitation in a target region given the proportions of moisture transported from the two sources (ocean and continent) to reveal that the percentage of precipitation of oceanic origin has increased globally in the current climate (1980–2016). The greatest observed rate of increase is in the tropical regions; furthermore, the trends of precipitation in these regions are controlled by trends in precipitation for which the source of moisture is the ocean.

The growing threat of multiyear droughts

American Association for the Advancement of Science (AAAS) | January 25th, 2025

Droughts have major societal and ecological impacts, including drinking water shortages, crop failures, tree mortality, wildfires, and reduced ecosystem productivity (1).

Droughts have major societal and ecological impacts, including drinking water shortages, crop failures, tree mortality, wildfires, and reduced ecosystem productivity (1). Shifts in the hydrological cycle and continued warming with climate change are leading to rapidly evolving droughts that are more intense and longer lasting (2). Extreme but short-term droughts (<1 year) can have a wide range of consequences, depending on the severity and timing of the drought as well as an ecosystem’s resistance (3, 4). However, as a drought extends to a multiyear event, these ecological effects can amplify because short-lived buffering from physiological adaptations or water storage may weaken, leading to longer-lasting results (4). On page 278 of this issue, Chen et al. (5) report that increasing precipitation anomalies and atmospheric moisture demands are leading to multiyear droughts with growing impacts on vegetation. This highlights the need to better understand the ecological responses to such drought events.

The Hardest Working River in the West: Common-Sense Solutions for a Reliable Water Future for the Colorado River Basin

Western Resource Advocates | July 14th, 2014

The majestic Colorado River cuts a 1,450-mile path through the American West before drying up well short of its natural finish line at the Gulf of California. Reservoirs

The majestic Colorado River cuts a 1,450-mile path through the American West before drying up well short of its natural finish line at the Gulf of California. Reservoirs once filled to the brim from the river and its tributaries are at historic lows due to an unprecedented drought and growing human demands. Diminished stream flows now pose serious challenges for wildlife and recreation, as well as cities, farms, and others who rely upon the river. Steps currently being taken to improve the situation are not up to the task of bringing the river system back into balance and providing a reliable water supply for all the communities who depend upon the Colorado River. Fortunately, we have five feasible, affordable, common-sense solutions that can be implemented now to protect the flow of the river, ensure greater economic vitality, and secure water resources for millions of Americans.

The hidden influence of terrestrial groundwater on salt marsh function and resilience

Nature Portfolio (Springer Nature) | February 3rd, 2025

Salt marshes are hotspots of nutrient processing and carbon sequestration. So far, studies addressing spatiotemporal variability in and drivers of salt marsh biogeochemic

Salt marshes are hotspots of nutrient processing and carbon sequestration. So far, studies addressing spatiotemporal variability in and drivers of salt marsh biogeochemical function, carbon storage and resilience have focused on ocean-driven surface hydrologic influences, neglecting effects of terrestrial hydrology through subsurface connections. Here we evaluate drivers of salt marsh redox potential, a proxy for biogeochemical state, through wavelet analyses and information theory using data from seven marshes. The results point to terrestrial groundwater level as a dominant control on redox variability across all sites. Because redox is a key driver of biogeochemical processes, and specifically oxidation of organic matter that sequesters carbon and maintains marsh elevation, these terrestrial influences are critical to understanding marsh function and evolution. The newly identified links between onshore groundwater levels and marsh redox conditions shift the traditional paradigm and suggest that terrestrial hydrology is a primary control on salt marsh carbon sequestration potential and resilience.