Colorado River

Recent decreases in snow water storage in western North America

Nature Portfolio (Springer Nature) | May 22nd, 2023

Mountain snowpacks act as natural water towers, storing winter precipitation until summer months when downstream water demand is greatest. We introduce a Snow Storage Ind

Mountain snowpacks act as natural water towers, storing winter precipitation until summer months when downstream water demand is greatest. We introduce a Snow Storage Index (SSI), representing the temporal phase difference between daily precipitation and surface water inputs—sum of rainfall and snowmelt into terrestrial systems—weighted by relative magnitudes. Different from snow water equivalent or snow fraction, the SSI represents the degree to which the snowpack delays the timing and magnitude of surface water inputs relative to precipitation, a fundamental component of how snow water storage influences the hydrologic cycle. In western North America, annual SSI has decreased (p 

Recent global decline in endorheic basin water storages

Nature Portfolio (Springer Nature) | November 30th, 2018

Endorheic (hydrologically landlocked) basins spatially concur with arid/semi-arid climates. Given limited precipitation but high potential evaporation, their water storag

Endorheic (hydrologically landlocked) basins spatially concur with arid/semi-arid climates. Given limited precipitation but high potential evaporation, their water storage is vulnerable to subtle flux perturbations, which are exacerbated by global warming and human activities. Increasing regional evidence suggests a probably recent net decline in endorheic water storage, but this remains unquantified at a global scale. By integrating satellite observations and hydrological modelling, we reveal that during 2002–2016 the global endorheic system experienced a widespread water loss of about 106.3 Gt yr−1, attributed to comparable losses in surface water, soil moisture and groundwater. This decadal decline, disparate from water storage fluctuations in exorheic basins, appears less sensitive to El Niño–Southern Oscillation-driven climate variability, which implies a possible response to longer-term climate conditions and human water management. In the mass-conserved hydrosphere, such an endorheic water loss not only exacerbates local water stress, but also imposes excess water on exorheic basins, leading to a potential sea level rise that matches the contribution of nearly half of the land glacier retreat (excluding Greenland and Antarctica). Given these dual ramifications, we suggest the necessity for long-term monitoring of water storage variation in the global endorheic system and the inclusion of its net contribution to future sea level budgeting.

Recharge Area Identification, Utilization, and Protection Resource Management Strategy

California Department of Water Resources (DWR) | April 29th, 2024

This resource management strategy (RMS) advances water supply augmentation, resilience, and equity in California by providing summaries of the state of knowledge, applica

This resource management strategy (RMS) advances water supply augmentation, resilience, and equity in California by providing summaries of the state of knowledge, applications, and available information and resources on recharge area identification, utilization, and protection.

Recharge Net Metering to Enhance Groundwater Sustainability

University of California, Berkeley (UC Berkeley) | April 2nd, 2018

Groundwater sustainability depends on balancing aquifer inflows and outflows. Extraction (pumping of groundwater, typically for human use) and recharge (inflow of

Groundwater sustainability depends on balancing aquifer inflows and outflows. Extraction (pumping of groundwater, typically for human use) and recharge (inflow of water to an aquifer from the land surface and streams) are central components of this water balance. Often, increasing demands for groundwater are exacer- bated by stresses on limited surface water supplies. Changes in land use and shifting climate can result in less infiltration of precipitation into the ground, reducing recharge. Increasing water scarcity has led to increased pumping, and in turn, unsustainable management of groundwater in many basins, resulting in depleted supplies, degraded water quality, and other impacts.

Recommendations to the State Water Resources Control Board Pursuant to California Water Code Section 10609

California Department of Water Resources (DWR) | September 29th, 2022

The Department of Water Resources (DWR) is pleased to provide the following recommendations developed in response to the 2018 Legislation (Senate Bill 606 [Hertzberg] and

The Department of Water Resources (DWR) is pleased to provide the following recommendations developed in response to the 2018 Legislation (Senate Bill 606 [Hertzberg] and Assembly Bill 1668 [Friedman]) enacted in support of “Making Water Conservation a California Way of Life.” The Legislation included provisions for advancing urban water use efficiency through developing and implementing various water use efficiency standards, variances for unique uses of water, and commercial, industrial, and institutional (CII) performance measures, among other requirements. Full reports detailing our methods, technical analyses, studies, public input, and recommendations will follow. These recommendations for long-term urban water use efficiency reflect technical considerations, public input, and the imperative to continue California’s progress in urban efficient use of water for future generations. If adopted DWR's recommendations on outdoor residential and CII water use on landscapes with dedicated irrigation meters, combined with the indoor residential water use standard recommendations submitted to the Legislature jointly by DWR and State Water Resources Control Board (State Water Board), pursuant to Water Code 10609.4 (b)(1), would result in expected long-term water savings of approximately 450,000 acre-feet per year starting in 2030 – considering 2019 population and 2017-2019 water use data, the water savings are enough to supply about 1.6 million homes or 4.7 million residents for both indoor and outdoor annual water needs.

Regional water table (1994) and water-level changes in the Morongo Basin, San Bernardino County, California

U.S. Geological Survey (USGS) | July 1st, 1995

The Morongo Basin is in the Mojave Desert region of southern California, about 100 mi east of Los Angeles. Ground water is virtually the sole source of water in the Moro

The Morongo Basin is in the Mojave Desert region of southern California, about 100 mi east of Los Angeles. Ground water is virtually the sole source of water in the Morongo Basin. Increased pumping to meet the needs of an increasing resident population has resulted in ground-water overdraft in parts of the ground-water basin. Most of the water resources of the basin are managed by the Mojave Water Agency (MWA) and the U.S. Marine Corps Air/Ground Combat Center at Twentynine Palms (USMCAGCC). To help manage the ground-water resources, the MWA and the U.S. Marine Corps, Department of the Navy, requested the U.S. Geological Survey (USGS) to construct a regional water-table map of the Morongo ground-water basin. The purposes of this study were to construct a regional water-table map and determine areas of water-level change in the Morongo Basin. Existing data were evaluated and water levels were measured in selected wells throughout the Morongo Basin. Water-level measurements were used to construct a regional water-table map for 1994 conditions (fig. 1), and available historical water levels were used to construct hydrographs (shown in fig. 1) and determine water-level change at selected wells. Results of this study will aid the USGS in evaluating its current ground-water monitoring network in the Morongo Basin. In addition, information gained through this study will contribute to ongoing projects in the area, such as the Regional Aquifer-System Analysis (RASA) of Southern California.

Regional water table (1996) and water-level changes in the Mojave River, Morongo, and Fort Irwin ground-water basins, San Bernardino County

U.S. Geological Survey (USGS) | July 1st, 1997

Regional water table (1998) and ground-water-level changes in the Mojave River and the Morongo ground-water basins, San Bernardino County, California

U.S. Geological Survey (USGS) | July 1st, 2000

Regional Water Table (1998) and Ground-Water-Level Changes in the Mojave River, and the Morongo Ground-Water Basins, San Bernardino County, California

U.S. Geological Survey (USGS) | July 15th, 2000

The Mojave River and the Morongo groundwater basins are in the southwestern part of the Mojave Desert in southern California. Ground water from these basins supplies a ma

The Mojave River and the Morongo groundwater basins are in the southwestern part of the Mojave Desert in southern California. Ground water from these basins supplies a major part of the water requirements for the region. The rapid and continuous population growth in this area has resulted in ever-increasing demands on local ground-water resources. The continuing collection and interpretation of ground-water data helps local water districts, military bases, and private citizens gain a better understanding of the ground-water systems and, consequently, water availability.

Regional Water Table (2000) and Ground-Water-Level Changes in the Mojave River and the Morongo Ground-Water Basins, Southwestern Mojave Desert, California

U.S. Geological Survey (USGS) | July 1st, 2003