Death Valley lower carbonate aquifer monitoring program—Wells down gradient of the proposed Yucca Mountain nuclear waste repository: U.S. Department of Energy Cooperative Agreement DE-FCO8-02RW12162 Final Project Report

Inyo County | July 1st, 2005

Death Valley regional ground-water flow system, Nevada and California—Hydrogeologic framework and transient ground-water flow model

U.S. Geological Survey (USGS) | July 1st, 2010

A numerical three-dimensional (3D) transient groundwater flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Ener

A numerical three-dimensional (3D) transient groundwater flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the groundwater flow system and previous less extensive groundwater flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect groundwater flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley regional groundwater flow system (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the groundwater flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural groundwater discharge occurring through evapotranspiration (ET) and spring flow; the history of groundwater pumping from 1913 through 1998; groundwater recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were provided by acquiring additional data, by reevaluating existing data using current technology and concepts, and by refining earlier interpretations to reflect the current understanding of the regional groundwater flow system. Groundwater flow in the Death Valley region is composed of several interconnected, complex groundwater flow systems. Groundwater flow occurs in three subregions in relatively shallow and localized flow paths that are superimposed on deeper, regional flow paths. Regional groundwater flow is predominantly through a thick Paleozoic carbonate rock sequence affected by complex geologic structures from regional faulting and fracturing that can enhance or impede flow. Spring flow and ET are the dominant natural groundwater discharge processes. Groundwater also is withdrawn for agricultural, commercial, and domestic uses. Groundwater flow in the DVRFS was simulated using MODFLOW-2000, the U.S. Geological Survey 3D finitedifference modular groundwater flow modeling code that incorporates a nonlinear least-squares regression technique to estimate aquifer parameters. The DVRFS model has 16 layers of defined thickness, a finite-difference grid consisting of 194 rows and 160 columns, and uniform cells 1,500 meters (m) on each side. Prepumping conditions (before 1913) were used as the initial conditions for the transient-state calibration. The model uses annual stress periods with discrete recharge and discharge components. Recharge occurs mostly from infiltration of precipitation and runoff on high mountain ranges and from a small amount of underflow from adjacent basins. Discharge occurs primarily through ET and spring discharge (both simulated as drains) and water withdrawal by pumping and, to a lesser amount, by underflow to adjacent basins simulated by constant-head boundaries. All parameter values estimated by the regression are reasonable and within the range of expected values. The simulated hydraulic heads of the final calibrated transient model generally fit observed heads reasonably well (residuals with absolute values less than 10 meters) with two exceptions: in most areas of nearly flat hydraulic gradient the fit is considered moderate (residuals with absolute values of 10 to 20 meters), and in areas of steep hydraulic gradient along the Eleana Range and western part of Yucca Flat, southern part of the Owlshead Mountains, southern part of the Bullfrog Hills, and the north-northwestern part of the model domain (residuals with absolute values greater than 20 meters). Groundwater discharge residuals are fairly random, with as many areas where simulated flows are less than observed flows as areas where simulated flows are greater. The highest unweighted groundwater discharge residuals occur at Death Valley, Sarcobatus Flat (northeastern area), Tecopa, and early observations at Manse Spring in Pahrump Valley. High weighted-discharge residuals were computed in Indian Springs Valley and parts of Death Valley. Most of these inaccuracies in head and discharge can be attributed to insufficient representation of the hydrogeology in the HFM and(or) discharge estimates, misrepresentation of water levels, and(or) model error associated with grid-cell size. The model represents the large and complex groundwater flow system of the Death Valley region at a greater degree of refinement and accuracy than has been possible previously. The representation of detail provided by the 3D digital hydrogeologic framework model and the numerical groundwater flow model enabled greater spatial accuracy in every model parameter. The lithostratigraphy and structural effects of the hydrogeologic framework; recharge estimates from simulated net infiltration; discharge estimates from ET, spring flow, and pumping; and boundary inflow and outflow estimates all were reevaluated, some additional data were collected, and accuracy was improved. Uncertainty in the results of the flow model simulations can be reduced by improving on the quality, interpretation, and representation of the water-level and discharge observations used to calibrate the model and improving on the representation of the HGU geometries, the spatial variability of HGU material properties, the flow model physical framework, and the hydrologic conditions.

Desalination Plant Entrainment Impacts and Mitigation

California State Water Resources Control Board (SWRCB) | October 9th, 2013

Raw seawater is used for a variety of purposes, including as source water for desalination plants and to cool coastal power plants. Raw seawater is, however, not just col

Raw seawater is used for a variety of purposes, including as source water for desalination plants and to cool coastal power plants. Raw seawater is, however, not just cold and salty but an ecosystem that contains diverse and abundant organisms including the young stages of numerous invertebrates and fishes. Whether impinged (large individuals stuck on screens prior to entering the plant or killed during other plant processes such as heat treatment) or entrained (small individuals carried into the plant with the water) the organisms are killed, essentially eliminating the living production in the water used (review in York and Foster 2005). Considerable research has have been done in California to better estimate losses to this ecosystem by coastal power plant intakes (York and Foster 2005, Steinbeck et al. 2007), and to determine how these losses can be mitigated (Strange et al. 2004). The information from this research has contributed to State of California policy regulating water used by power plants.

Dimension reduction approach for understanding resource-flow resilience to climate change

Nature Portfolio (Springer Nature) | June 15th, 2024

Energizing Water Efficiency: California Energy Sector Experiences Can Advance State’s Water Conservation and Efficiency

Pacific Institute | December 29th, 2013

As a dry December accentuates the stress on California’s limited water supplies, the success of the state’s energy sector in implementing efficiency programs offers v

As a dry December accentuates the stress on California’s limited water supplies, the success of the state’s energy sector in implementing efficiency programs offers valuable lessons to the water sector. A new report from the Pacific Institute examines the rules, regulations, and policies that promote energy efficiency and finds models for water management in drivers like the energy sector’s appliance standards, building codes, pricing policies, and utility-sponsored efficiency programs. California has made remarkable improvements in energy efficiency over the last several decades and is recognized as a national leader. The state’s per capita electricity and natural gas consumption is about 45% and 30% less, respectively, than other Americans. Indeed, California’s per capita electricity consumption has remained largely unchanged since the mid-1970s – while increasing by more than 50% across the U.S.  Efficiency policies, including incentive and education programs, have been a major factor in reducing per capita energy use in California. In water conservation and efficiency, California has also made major advances. Many urban areas across the state, including Los Angeles and San Francisco, are serving a larger population with the same or even less water than 20 years ago. But with increasing pressure on water supply from population and economic growth, the need to restore freshwater ecosystems, and climate change, greater water conservation and efficiency are essential. “Reductions in per-capita water demand have been driven first by a shift to a less water-intensive service-oriented economy, and second by federal, state, and local policies as well as utility programs facilitating water-efficiency improvements,” said Heather Cooley, co-director of the Pacific Institute Water Program. “We must examine new approaches for achieving even greater savings to address the water challenges we now face.” The Pacific Institute report identifies programs that have worked for the energy sector and offers recommendations for how they could be adapted to the water sector. First among them are to continuously update standards and codes for fixtures and buildings to capture new technologies and practices.

Energy and water co-benefits from covering canals with solar panels

Nature Portfolio (Springer Nature) | March 18th, 2021

Solar power development over canals is an emerging response to the energy–water–food nexus that can result in multiple benefits for water and energy infrastructure. C

Solar power development over canals is an emerging response to the energy–water–food nexus that can result in multiple benefits for water and energy infrastructure. Case studies of over-canal solar photovoltaic arrays have demonstrated enhanced photovoltaic performance due to the cooler microclimate next to the canal. In addition, shade from the photovoltaic panels has been shown to mitigate evaporation and potentially mitigate aquatic weed growth. However, the evaporation savings and financial co-benefits have not been quantified across major canal systems. Here we use regional hydrologic and techno-economic simulations of solar photovoltaic panels covering California’s 6,350 km canal network, which is the world’s largest conveyance system and covers a wide range of climates, insolation rates and water costs. We find that over-canal solar could reduce annual evaporation by an average of 39 ± 12 thousand m3 per km of canal. Furthermore, the financial benefits from shading the canals outweigh the added costs of the cable-support structures required to span the canals. The net present value of over-canal solar exceeds conventional overground solar by 20–50%, challenging the convention of leaving canals uncovered and calling into question our understanding of the most economic locations for solar power.

Energy Down the Drain: The Hidden Costs of California’s Water Supply

Pacific Institute | August 24th, 2004

As California’s electricity demand sets record highs and the Southwest is parched by drought, Energy Down the Drain: The Hidden Cost of California’s Water Supply b

As California’s electricity demand sets record highs and the Southwest is parched by drought, Energy Down the Drain: The Hidden Cost of California’s Water Supply by the Pacific Institute and the NRDC shows the hidden connection between energy and water. “With power shortages and a water scarcity a constant threat across the West, it’s time to look at water and energy in a new way,” said Dr. Gary Wolff a co-author of the report and Principal Economist and Engineer with the Pacific Institute. “But too often, policymakers and water and energy experts ignore the links. The good news is we can reduce our energy use, cut air pollution and create new energy supplies with cost-effective improvements to water efficiency.”

Energy Down the Drain. The Hidden Costs of California's Water Supply

Natural Resources Defense Council (NRDC) | August 2nd, 2004

California has been through its share of scorching droughts and energy shortages, but many residents of the western United States may not realize the close con- n

California has been through its share of scorching droughts and energy shortages, but many residents of the western United States may not realize the close con- nections between water and power resources. Water utilities use large amounts of energy to treat and deliver water. Even after utilities deliver water, consumers burn more energy to heat, cool, and use the water. The California State Water Project is the largest single user of energy in California. In the process of delivering water from the San Francisco Bay-Delta to Southern California, the project uses 2 to 3 percent of all electricity consumed in the state. The State Water Project burns energy pumping water 2,000 feet over the Tehachapi Mountains—the highest lift of any water system in the world. The amount of energy used to deliver that water to residential customers in Southern California is equivalent to approximately one-third of the total average household electric use in the region. Ninety percent of all electricity used on farms is devoted to pumping groundwater for irrigation.

Energy production and water savings from floating solar photovoltaics on global reservoirs

Nature Portfolio (Springer Nature) | March 13th, 2023

Growing global energy use and the adoption of sustainability goals to limit carbon emissions from fossil fuel burning are increasing the demand for clean energy, includin

Growing global energy use and the adoption of sustainability goals to limit carbon emissions from fossil fuel burning are increasing the demand for clean energy, including solar. Floating photovoltaic (FPV) systems on reservoirs are advantageous over traditional ground-mounted solar systems in terms of land conservation, efficiency improvement and water loss reduction. Here, based on multiple reservoir databases and a realistic climate-driven photovoltaic system simulation, we estimate the practical potential electricity generation for FPV systems with a 30% coverage on 114,555 global reservoirs is 9,434 ± 29 TWh yr−1. Considering the proximity of most reservoirs to population centres and the potential to develop dedicated local power systems, we find that 6,256 communities and/or cities in 124 countries, including 154 metropolises, could be self-sufficient with local FPV plants. Also beneficial to FPV worldwide is that the reduced annual evaporation could conserve 106 ± 1 km3 of water. Our analysis points to the huge potential of FPV systems on reservoirs, but additional studies are needed to assess the potential long-term consequences of large systems.

Estimated ground-water discharge by evapotranspiration from Death Valley, California

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