Exploring the Spatially Compounding Multi‐Sectoral Drought Vulnerabilities in Colorado's West Slope River Basins

American Geophysical Union (AGU) | November 9th, 2024

Exploring Water System Vulnerabilities in California's Central Valley Under the Late Renaissance Megadrought and Climate Change

American Geophysical Union (AGU) | April 24th, 2025

Extreme hydrological changes in the southwestern US drive reductions in water supply to Southern California by mid century

Environmental Research Letters (IOP) | September 21st, 2016

The Southwestern United States has a greater vulnerability to climate change impacts on water security due to a reliance on snowmelt driven imported water. The State of C

The Southwestern United States has a greater vulnerability to climate change impacts on water security due to a reliance on snowmelt driven imported water. The State of California, which is the most populous and agriculturally productive in the United States, depends on an extensive arti cial water storage and conveyance system primarily for irrigated agriculture, municipal and industrial supply and hydropower generation. Here we take an integrative high-resolution ensemble modeling approach to examine near term climate change impacts on all imported and local sources of water supply to Southern California. While annual precipitation is projected to remain the same or slightly increase, rising temperatures result in a shift towards more rainfall, reduced cold season snowpack and earlier snowmelt. Associated with these hydrological changes are substantial increases in the frequency and the intensity of both drier conditions and ooding events. The 50 year extreme daily maximum precipitation and runoff events are 1.5–6 times more likely to occur depending on the water supply basin. Simultaneously, a clear de cit in total annual runoff over mountainous snow generating regions like the Sierra Nevada is projected. On one hand, the greater probability of drought decreases imported water supply availability. On the other hand, earlier snowmelt and signicantly stronger winter precipitation events pose increased flood risk requiring water releases from control reservoirs, which may potentially decrease water availability outside of the wet season. Lack of timely local water resource expansion coupled with projected climate changes and population increases may leave the area in extended periods of shortages.

Extreme Precipitation-Temperature Scaling in California: The Role of Atmospheric Rivers

American Geophysical Union (AGU) | July 25th, 2023

Flood-Hazard Study -- 100 Year Flood Stage for Lucerne Lake, San Bernardino County, California

U.S. Geological Survey (USGS) | July 15th, 1977

Flood-Hazard Study -- 100-Year Flood Stage for Apple Valley Dry Lake, San Bernardino County, California

U.S. Geological Survey (USGS) | June 30th, 1975

A study of the flood hydrology of Apple Valley, Calif., was undertaken to develop the 100—year flood stage for Apple Valley dry lake. Synthetic hydrologic techniques we

A study of the flood hydrology of Apple Valley, Calif., was undertaken to develop the 100—year flood stage for Apple Valley dry lake. Synthetic hydrologic techniques were used because no adequate hydrologic or meteorologic data were available for the basin. The 100—year flood stage was estimated to be at an elevation of 2,909.0 feet (886.7 metres) above mean sea level.

From Climate Traces to Climate Insights: Future Scenarios Analysis for the California Central Valley

California Department of Water Resources (DWR) | October 2nd, 2023

California Water Code Section 10004.6 requires the California Department of Water Resources (DWR) to quantify current and future water conditions in the state. This infor

California Water Code Section 10004.6 requires the California Department of Water Resources (DWR) to quantify current and future water conditions in the state. This information is published in the California Water Plan (Water Plan), which is updated every five years. Water managers and planners constantly face the challenges of planning for an uncertain future where the only constant is change. To address the potential future changes and mitigate the probable risks, water managers must consider and quantify uncertainties and their impacts on water system vulnerability. Although it is not possible to know for certain how population growth, land use decisions, climate, and other factors change over time, water planners must consider these system stressors in long-term planning to evaluate future risks and uncertainty. The Water Plan evaluates many alternative future scenarios as an integral part of its analytical approach to quantify system vulnerability under a range of population and urban growth scenarios, land use, and climate uncertainties.

From Climate-Change Spaghetti to Climate-Change Distributions for 21st Century California

University of California, Davis (UC Davis) | March 1st, 2005

The uncertainties associated with climate-change projections for California are unlikely to disappear anytime soon, and yet important long-term decisions will be needed t

The uncertainties associated with climate-change projections for California are unlikely to disappear anytime soon, and yet important long-term decisions will be needed to accommodate those potential changes. Projection uncertainties have typically been addressedby analysis of a few scenarios, chosen based on availability or to capture the extreme cases among available projections. However, by focusing on more com-mon projections rather than the most extreme projections (using a new resampling method), new insights into current projections emerge: (1) uncertainties associated with future greenhouse-gas emissions are comparable with the differences among climate models, so that neither source of uncertainties should be neglected or underrepresented; (2) twenty-first century temperature projections spread more, overall, than do precipitation scenarios; (3) projections of extremely wet futures for California are true outliers among current projections; and (4) current projections that are warmest tend, overall, to yield a moderately drier California, while the cooler projections yield a some-what wetter future. The resampling approach appliedin this paper also provides a natural opportunity to objectively incorporate measures of model skill and the likelihoods of various emission scenarios into future assessments.

Fundamentals of estimating the net benefits of ecosystem preservation: The case of the Salton Sea

Hydrobiologia (Springer) | July 15th, 2008

This article, both theoretical and methodological in nature, argues the potential merits of using a net benefits’ framework as a tool to aid policy-makers in their eff

This article, both theoretical and methodological in nature, argues the potential merits of using a net benefits’ framework as a tool to aid policy-makers in their efforts to compare Salton Sea restoration alternatives and inform the public as to the potential magnitude and distribution of trade-offs associated with each alternative. A net benefits approach can provide a more accurate comparison and evaluation of the potential net returns from public spending on Salton Sea restoration than what wouldbe provided under the suggested criteria of current legislative mandates. Furthermore, a net benefits framework provides a more lucid and systematic accounting framework by which to enumerate the full array of benefits and costs of each alternative for policy analysis. Finally, net benefits’ analysis serves to add transparency to the decision-making process sothat the public gains an understanding of how its scarce resources, including both financial and natural capital, are being appropriated. Additionally, we illustrate and emphasize the importance of estimating the non-market values associated with many of the ecosystem services provided by the Salton Sea and describe the major techniques that do so.

Future Atmospheric Rivers and Impacts on Precipitation: Overview of the ARTMIP Tier 2 High-Resolution Global Warming Experiment

American Geophysical Union (AGU) | March 14th, 2023

Atmospheric rivers (ARs) are long and narrow weather features often referred to as “rivers in the sky.” They often transport water from lower latitudes to higher lati

Atmospheric rivers (ARs) are long and narrow weather features often referred to as “rivers in the sky.” They often transport water from lower latitudes to higher latitudes typically across climate zones and produce precipitation necessary for local climates. Understanding ARs in a warming climate is challenging because of the variety of ways an AR can be defined on gridded data sets. Unlike weather features such as tropical cyclones where identification methodologies are similar, algorithms that determine the characteristics of ARs vary depending on the science question posed. Because there is no real consensus on AR identification methodology, we aim to quantify the algorithmic uncertainty in AR metrics and precipitation. We compare 16 different ways of defining an AR on gridded data sets and present the range of possibilities in which an AR could change under global warming. Generally, ARs are projected to increase but the amount of that increase is a function of the algorithm. Across all algorithms and focus regions, AR precipitation is projected to become more extreme.