Climate-informed hydrologic modeling and policy typology to guide managed aquifer recharge

American Association for the Advancement of Science (AAAS) | April 21st, 2021

Harvesting floodwaters to recharge depleted groundwater aquifers can simultaneously reduce flood and drought risks and enhance groundwater sustainability. However, deploy

Harvesting floodwaters to recharge depleted groundwater aquifers can simultaneously reduce flood and drought risks and enhance groundwater sustainability. However, deployment of this multibeneficial adaptation option is fundamentally constrained by how much water is available for recharge (WAFR) at present and under future climate change. Here, we develop a climate-informed and policy-relevant framework to quantify WAFR, its uncertainty, and associated policy actions. Despite robust and widespread increases in future projected WAFR in our case study of California (for 56/80% of subbasins in 2070–2099 under RCP4.5/RCP8.5), strong nonlinear interactions between diversion infrastructure and policy uncertainties constrain how much WAFR can be captured. To tap future elevated recharge potential through infrastructure expansion under deep uncertainties, we outline a novel robustness-based policy typology to identify priority areas of investment needs. Our WAFR analysis can inform effective investment decisions to adapt to future climate-fueled drought and flood risk over depleted aquifers, in California and beyond.

Coachella Valley Water District Engineer's Report on Water Supply and Replenishment Assessment for the East Whitewater River Subbasin Area of Benefit

Coachella Valley Water District (CVWD) | April 15th, 2015

Coachella Valley Water District (CVWD) and Desert Water Agency (DWA) have been importing Colorado River water exchanged for State Water Project (SWP) water alloca

Coachella Valley Water District (CVWD) and Desert Water Agency (DWA) have been importing Colorado River water exchanged for State Water Project (SWP) water allocations to replenish the groundwater within the Coachella Valley Groundwater Basin since 1973. Groundwater replenishment within the East Whitewater River Subbasin began in 1997 through a pilot program at the Thomas E. Levy Groundwater Replenishment Facility (TEL Replenishment Facility). In 2004, the Martinez Canyon pilot project was brought online. If groundwater replenishment with imported water is eliminated, groundwater overdraft will result. Increased overdraft results in declining water levels, increased pump lifts, and increased energy consumption to pump groundwater for irrigation and domestic use. Extreme overdraft has the potential to cause ground surface subsidence and to impact water quality and groundwater storage volume.

Colusa County | Managed Aquifer Recharge: benefitting aquifers, farmers, and migratory birds

Nature Conservancy | September 3rd, 2018

In partnership with growers and the Colusa Groundwater Authority (CGA), The Nature Conservancy (TNC) is implementing a pilot multiple-benefit managed aquifer r

In partnership with growers and the Colusa Groundwater Authority (CGA), The Nature Conservancy (TNC) is implementing a pilot multiple-benefit managed aquifer recharge (MAR) program on farmland in California’s Central Valley, Colusa County. This program will benefit local groundwater users by replenishing critical domestic and agricultural groundwater supplies in a Severely Disadvanateged Community (SDAC). Participating farmers will benefit economically through incentive payments, and migratory shorebirds will benefit through the creation of critical winter habitat on farms through our specific field and water depth specificiations. MAR sites will be selected where and when it is appropriate and cost-effective to do so based on farming practices, soil suitability, water availability, basin water balances, and migratory/shorebird habitat requirements. The relevance and success of this program for Groundwater Sustainability Agencies (GSAs), Severely Disadvantaged Communities (SDACs), and Groundwater Sustainability Plans (GSPs) will require all of these stakeholders and project participants to collaborate on its design. Thus, TNC will engage growers, water managers, and other stakeholders in a variety of formal and informal ways to ensure that this program will meet the needs of all parties involved in GSP development. This program serves as a model for other GSAs and stakeholders seeking to deliver multiple benefits through on-farm recharge in the Central Valley where such a program is appropriate.

Comment on “Short-lived pause in Central California subsidence after heavy winter precipitation of 2017” by K. D. Murray and R. B. Lohman

American Association for the Advancement of Science (AAAS) | June 12th, 2019

In a study by Murray and Lohman (M&L), the authors suggest that remote sensing data are useful for monitoring land subsidence due to aquifer system compacti

In a study by Murray and Lohman (M&L), the authors suggest that remote sensing data are useful for monitoring land subsidence due to aquifer system compaction. We agree. To infer aquifer dynamics, we provide a more detailed and joint analysis of deformation and groundwater data. Investigating well data in the Tulare Basin, we find that groundwater levels stabilized before 2015 and show that M&L’s observed continued subsidence through July 2016 is likely caused by the delayed compaction of the aquitard. Our analysis suggests the observed 2017 transient uplift is not due to recharge of the aquifer system after heavy winter rainfall because it requires an unrealistic vertical hydraulic gradient nearly five orders of magnitude larger than that typical of Tulare Basin. We find that, regardless of the amount of rainfall, transient annual uplifts of ~3 cm occur in May to June. Using an elastic skeletal storage coefficient of 5 × 10−3, we link this ground uplift to annual groundwater level changes.

Conjunctive Water Management Resource Management Strategy

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

Conjunctive water management, also referred to as conjunctive use, is broadly defined as the coordinated and planned use and management of the different sources of water

Conjunctive water management, also referred to as conjunctive use, is broadly defined as the coordinated and planned use and management of the different sources of water in time and space. It is usually focused on surface water and groundwater resources to maximize the availability and reliability of water supplies in a region to meet various management objectives. It is a holistic approach to water resource management that can increase available water for beneficial uses, allow water agencies greater flexibility in scheduling deliveries, and improve drought resiliency (California Department of Water Resources 2003).

County of San Bernardino Hydrology Manual

San Bernardino County | August 1st, 1986

Coupling a spatiotemporally distributed soil water budget with stream-depletion functions to inform stakeholder-driven management of groundwater-dependent ecosystems

Water Resources Research, American Geophysical Union | November 12th, 2013

Groundwater pumping, even if only seasonal, may significantly impact groundwater-dependent ecosystems through increased streamflow depletion, particularly in semiarid and

Groundwater pumping, even if only seasonal, may significantly impact groundwater-dependent ecosystems through increased streamflow depletion, particularly in semiarid and arid regions. The effects are exacerbated, under some conditions, by climate change. In social sciences, the management of groundwater-dependent ecosystems is generally considered a “wicked” problem due to the complexity of affected stakeholder groups, disconnected legal frameworks, and a divergence of policies and science at the cross road between groundwater and surface water, and between ecosystems and water quality. A range of often simplified scientific tools plays an important role in addressing such problems. Here we develop a spatiotemporally distributed soil water budget model that we couple with an analytical model for stream depletion from groundwater pumping to rapidly assess seasonal impacts of groundwater pumping on streamflow during critical low flow periods. We demonstrate the applicability of the tool for the Scott Valley in Northern California, where protected salmon depend on summer streamflow fed by cool groundwater. In this example, simulations suggest that increased recharge in the period immediately preceding the critical low streamflow season, and transfer of groundwater pumping away from the stream are potentially promising tools to address ecosystem concerns, albeit raising difficult infrastructure and water trading issues. In contrast, additional winter recharge at the expense of later spring recharge, whether intentional or driven by climate may reduce summer streamflows. Comparison to existing detailed numerical groundwater model results suggests that the coupled soil water mass balance—stream depletion function approach provides a viable tool for scenario development among stakeholders, to constructively inform the search for potential solutions, and to direct more detailed, complex site-specific feasibility studies. The tool also identifies important field monitoring efforts needed to improve the understanding and quantification of site-specific groundwater-stream interactions.

CV-SALTS Groundwater Sustainability Plan Data Collection - Pilot Study Results

Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) | February 1st, 2024

The purpose of Prioritization & Optimization (P&O) Study Task 5.3 (Information Extraction from Groundwater Sustainability Plans [GSP]) is to extract and organize relevan

The purpose of Prioritization & Optimization (P&O) Study Task 5.3 (Information Extraction from Groundwater Sustainability Plans [GSP]) is to extract and organize relevant GSP data and information that can be used to (1) validate or refine information contained in the P&O Study’s CV-SWAT watershed model (developed to support ongoing baseline characterization work); (2) support the eventual development of salinity management alternatives within specified planning areas; and (3) help ensure that long-term Central Valley salt planning considers ongoing Groundwater Sustainability Agency (GSA) planning efforts, which is of particular interest to the State Water Resources Control Board.

Data from a Thick Unsaturated Zone Underlying Oro Grande and Sheep Creek Washes in the Western Part of the Mojave Desert, near Victorville, San Bernardino County, California

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

This report presents data collected as part of a cooperative study of infiltration and groundwater recharge to the regional aquifer near Victorville, California.

This report presents data collected as part of a cooperative study of infiltration and groundwater recharge to the regional aquifer near Victorville, California. The study was funded by the U.S. Geological Survey (USGS) and the Mojave Water Agency. This report contains data on drilling, instrument installation, the physical properties of unsaturated earth materials, and the chemical and isotopic composition of leachate from cores and cuttings, soil water, and soil gas collected at sites underlying Oro Grande and Sheep Creek Washes in the Mojave Desert. The report also presents similar data collected at sites on the alluvial fan near these washes and at a site near Cajon Pass. The sites on the alluvial fan and near Cajon Pass served as controls for the study and allow for comparison with data from previous studies. In addition, the report presents data on the chemical and isotopic composition of bulk precipitation, and on groundwater levels and quality. Interpretation of these data is beyond the scope of this report.

Degradation of floodplain integrity within the contiguous United States

Nature Portfolio (Springer Nature) | June 15th, 2023