Appraisal of the water resources of Death Valley, California–Nevada

U.S. Geological Survey (USGS) | December 1st, 1977

Approaches to Planning Water Resources

University of California, Davis (UC Davis) | July 15th, 2008

This paper attempts to summarize and organize various technical  approaches often seen or discussed for water resources planning. The basic approach to rational planning

This paper attempts to summarize and organize various technical  approaches often seen or discussed for water resources planning. The basic approach to rational planning is presented, followed by brief reviews of Requirements-based, Benefit-Cost-based, Multi-objective, Conflict Resolution, Market-based, and Muddling Through approaches to planning. Each approach has particular advantages and disadvantages for specific situations. Each approach also tends to have somewhat different analytical requirements. These approaches are discussed in terms of practical contributions to solving long-term water problems in contemporary contexts.

Approved Determination of the Revised Groundwater Sustainability Plan Submitted for the San Joaquin Valley – Merced Subbasin

California Department of Water Resources (DWR) | August 4th, 2023

Are Atmospheric Models Too Cold in the Mountains? The State of Science and Insights from the SAIL Field Campaign

American Meteorological Society (AMS) | July 16th, 2024

Artes: An Integrated Model of Water Supply in L.A. County

University of California, Los Angeles (UCLA) | May 1st, 2017

Los Angeles faces a future with less imported water. Infrastructure and institutions will have to adapt. Understanding emerging policy and investment needs requires anal

Los Angeles faces a future with less imported water. Infrastructure and institutions will have to adapt. Understanding emerging policy and investment needs requires analysis across systems, a typically elusive goal within the diverse and disparately managed water systems of L.A. A more comprehensive analysis of water resources in Los Angeles requires an understanding of people, pipes, and plants. It could also be flexible to incorporate the fast-changing landscape of models, data, and analysis that the active agencies of the region continue to develop. With these goals in mind, we developed a water supply model for the metropolitan L.A. County region (Artes) to understand the potential for enhancing local water use across scenarios of demand and supply. The basic approach combines knowledge from engineering, hydrology, ecology, and sociology. The model is intentionally lightweight. Flexible and adaptive modeling can address many questions at multiple geographic scales, while also being able to incorporate new tools, data, and other models that are released. This model was developed to: * Determine how local groundwater, recycling and stormwater capture supplies could maximally meet water demands across L.A. County, based on current knowledge of hydrology and hydrogeology * Analyze tradeoffs in per capita water demand and available imported water supplies * Investigate system-wide effects of increased conservation * Minimize assumptions regarding data gaps * Use modeling to highlight to key gaps in scientific understanding, while creatively addressing the shortfalls in a precautionary manner. For instance, we compare modeled and historic groundwater pumping and managed aquifer recharge to assess the potential for groundwater overdraft. This manual describes important information for understanding model operations, assumptions, inputs, and outputs. The manual version (3.7) was written after development of 3 versions code for different research studies, which are in press or under review.

Assessing Regional Strategies to Cope with Drought, Climate, and Environmental Flow Policy Impacts for a Sustainable Water Supply: A Case Study of the Bay Area

American Chemical Society (ACS) | December 27th, 2024

Assessing the Effects of Climate Change on Middle Rio Grande Surface Water Supplies Using a Simple Water Balance Reservoir Model

American Meteorological Society (AMS) | August 12th, 2022

The middle Rio Grande is a vital source of water for irrigation in the region. Climate change is impacting regional hydrology and is likely to put additional stress on a

The middle Rio Grande is a vital source of water for irrigation in the region. Climate change is impacting regional hydrology and is likely to put additional stress on a water supply that is already stretched thin. To gain insight on the hydrologic effects of climate change on reservoir storage, a simple water balance model was used to simulate the Elephant Butte–Caballo Reservoir system (southern New Mexico). The water balance model was forced by hydrologic inputs generated by 97 climate simulations derived from CMIP5 global climate models, coupled to a surface hydrologic model. Results suggest that the percentage of years that reservoir releases satisfy agricultural water rights allocations over the next 50 years (2021–70) will decrease relative to the past 50 years (1971–2020). The modeling also projects an increase in multiyear drought events that hinder reservoir management strategies to maintain high storage levels. In most cases, changes in reservoir inflows from distant upstream snowmelt is projected to have a greater influence on reservoir storage and water availability downstream of the reservoirs than will changes in local evaporation and precipitation from the reservoir surfaces.

Asymmetric emergence of low-to-no snow in the midlatitudes of the American Cordillera

Nature Portfolio (Springer Nature) | November 14th, 2022

Societies and ecosystems within and downstream of mountains rely on seasonal snowmelt to satisfy their water demands. Anthropogenic climate change has reduced mountain sn

Societies and ecosystems within and downstream of mountains rely on seasonal snowmelt to satisfy their water demands. Anthropogenic climate change has reduced mountain snowpacks worldwide, altering snowmelt magnitude and timing. Here the global warming level leading to widespread and persistent mountain snowpack decline, termed low-to-no snow, is estimated for the world’s most latitudinally contiguous mountain range, the American Cordillera. We show that a combination of dynamical, thermodynamical and hypsometric factors results in an asymmetric emergence of low-to-no-snow conditions within the midlatitudes of the American Cordillera. Low-to-no-snow emergence occurs approximately 20 years earlier in the southern hemisphere, at a third of the local warming level, and coincides with runoff efficiency declines (8% average) in both dry and wet years. The prevention of a low-to-no-snow future in either hemisphere requires the level of global warming to be held to, at most, +2.5 °C.

At Risk: Public Supply Well Vulnerability Under California’s Sustainable Groundwater Management Act

Pacific Institute | June 1st, 2021

August 2025 Probable Maximum 24-Month Study

U.S. Bureau of Reclamation (USBR) | August 15th, 2025

In addition to the August 2025 24-Month Study based on the Most Probable inflow scenario, and in accordance with the Upper Basin Drought Response Operations Agreement (DR

In addition to the August 2025 24-Month Study based on the Most Probable inflow scenario, and in accordance with the Upper Basin Drought Response Operations Agreement (DROA), Reclamation has conducted additional model runs in August to determine a possible range of reservoir elevations. Probable minimum and probable maximum model runs are conducted in January, April, August, and October, or when necessary to incorporate changing conditions. The Probable Minimum inflow scenario reflects a dry hydrologic condition which statistically would be exceeded 90% of the time. The Most Probable inflow scenario reflects a median hydrologic condition which statistically would be exceeded 50% of the time. The Probable Maximum inflow scenario reflects a wet hydrologic condition which statistically would be exceeded 10% of the time. There is approximately an 80% probability that a future elevation will fall inside the range of the minimum and maximum inflow scenarios. Additionally, there are possible inflow scenarios that would result in reservoir elevations falling outside the ranges indicated in these reports. Related scenarios: August 2025 Most Probable 24-Month Study August 2025 Probable Minimum 24-Month Study