Groundwater-Flow and Land-Subsidence Model of Antelope Valley, California

U.S. Geological Survey (USGS) | October 27th, 2014

Antelope Valley, California, is a topographically closed basin in the western part of the Mojave Desert, about 50 miles northeast of Los Angeles. The Antelope Valley grou

Antelope Valley, California, is a topographically closed basin in the western part of the Mojave Desert, about 50 miles northeast of Los Angeles. The Antelope Valley groundwater basin is about 940 square miles and is separated from the northern part of Antelope Valley by faults and low-lying hills. Prior to 1972, groundwater provided more than 90 percent of the total water supply in the valley; since 1972, it has provided between 50 and 90 percent. Most groundwater pumping in the valley occurs in the Antelope Valley groundwater basin, which includes the rapidly growing cities of Lancaster and Palmdale. Groundwater-level declines of more than 270 feet in some parts of the groundwater basin have resulted in an increase in pumping lifts, reduced well efficiency, and land subsidence of more than 6 feet in some areas. Future urban growth and limits on the supply of imported water may increase reliance on groundwater. In 2011, the Los Angeles County Superior Court of California ruled that the Antelope Valley groundwater basin is in overdraft—groundwater extractions are in excess of the Court-defined safe yield of the groundwater basin. The Court determined that the safe yield of the adjudicated area of the basin was 110,000 acre-feet per year (acre-ft/yr). Natural recharge is an important component of total groundwater recharge in Antelope Valley; however, the exact quantity and distribution of natural recharge, primarily in the form of mountain-front recharge, is uncertain, with total estimates ranging from 30,000 to 160,000 acre-ft/yr. Technical experts, retained by parties to the adjudication, used 60,000 acre-ft/yr to estimate the sustainable yield of the basin, and this value was used in this study. In order to better understand the uncertainty associated with natural recharge and to provide a tool to aid in groundwater management, a numerical model of groundwater flow and land subsidence in the Antelope Valley groundwater basin was developed using old and new geohydrologic information. The groundwater-flow system consists of three aquifers: the upper, middle, and lower aquifers. The three aquifers, which were identified on the basis of the hydrologic properties, age, and depth of the unconsolidated deposits, consist of gravel, sand, silt, and clay alluvial deposits and clay and silty clay lacustrine deposits. Prior to groundwater development in the valley, recharge was primarily the infiltration of runoff from the surrounding mountains. Groundwater flowed from the recharge areas to discharge areas around the playas where it discharged from the aquifer system as either evapotranspiration or from springs. Partial barriers to horizontal groundwater flow, such as faults, have been identified in the groundwater basin. Water-level declines owing to groundwater development have eliminated the natural sources of discharge, and pumping for agricultural and urban uses have become the primary source of discharge from the groundwater system. Infiltration of return flow from agricultural irrigation has become an important source of recharge to the aquifer system.

Guidebook to studies of land subsidence due to ground-water withdrawal

United Nations Educational, Scientific and Cultural Organization (UNESCO) | July 1st, 1984

Hemet San Jacinto Stipulated Judgment

Superior Court of California, County of Riverside | April 18th, 2013

Background from "An Evaluation of California’s Adjudicated Groundwater Basins," Langridge et al, 2016 (UC Davis) Groundwater problems in the San Jacinto Basin were f

Background from "An Evaluation of California’s Adjudicated Groundwater Basins," Langridge et al, 2016 (UC Davis) Groundwater problems in the San Jacinto Basin were first addressed by the court in a 1954 judgment that allocated pumping rights for the Fruitvale Mutual Water Company in the upper San Jacinto Basin. Declining groundwater levels persisted into the 1970s, and local water purveyors attempted to develop a groundwater management plan to address the declines. Eastern Municipal Water District (EMWD), which had acquired the Fruitvale Company in 1972, worked with the water purveyors in the 1990s to implement an AB 3030 groundwater management plan for the West San Jacinto Groundwater Management Area. In 2001, a Memorandum of Understanding between the Department of Water Resources (DWR) and local agencies required a water management plan for the Hemet/San Jacinto Groundwater Management Area, the eastern portion of the San Jacinto Basin, and a plan was released in 2007. At the same time, the Soboba Band of Luiseño Indians, negotiating with the local agencies to specify their groundwater rights from the Hemet/San Jacinto Groundwater Management Area, also pushed for a management plan. These negotiations culminated in the 2008 Soboba Settlement Agreement Act that established their water rights. A 2013 stipulated judgment allocated pumping rights for public water agencies, provided for water rights outlined in the Soboba Settlement Agreement, incorporated the Water Management Plan, and mandated a Watermaster."

Hydraulic and mechanical properties affecting ground‐water flow and aquifer‐system compaction, San Joaquin Valley, California

U.S. Geological Survey (USGS) | July 19th, 2001

This report summarizes hydraulic and mechanical properties affecting ground-water flow and aquifer-system compaction in the San Joaquin Valley, a broad alluviated inte

This report summarizes hydraulic and mechanical properties affecting ground-water flow and aquifer-system compaction in the San Joaquin Valley, a broad alluviated intermontane structural trough that constitutes the southern two-thirds of the Central Valley of California. These values will be used to constrain a coupled ground-water flow and aquifer-system compaction model of the western San Joaquin Valley called WESTSIM. A main objective of the WESTSIM model is to evaluate potential future land subsidence that might occur under conditions in which deliveries of imported surface water for agricultural use are reduced and ground-water pumping is increased. Storage values generally are components of the total aquifer-system storage and include inelastic and elastic skeletal storage values of the aquifers and the aquitards that primarily govern the potential amount of land subsidence. Vertical hydraulic conductivity values generally are for discrete thicknesses of sediments, usually aquitards, that primarily govern the rate of land subsidence. The data were compiled from published sources and include results of aquifer tests, stress-strain analyses of borehole extensometer observations, laboratory consolidation tests, and calibrated models of aquifer-system compaction.

Hydroeconomic modeling of sustainable groundwater management

American Geophysical Union (AGU) | March 23rd, 2017

In 2014, California passed legislation requiring the sustainable management of critically over-drafted groundwater basins, located primarily in the Central Valley agricu

In 2014, California passed legislation requiring the sustainable management of critically over-drafted groundwater basins, located primarily in the Central Valley agricultural region. Hydroeconomic modeling of the agricultural economy, groundwater, and surface water systems is critically important to simulate potential transition paths to sustainable management of the basins. The requirement for sustainable groundwater use by 2040 is mandated for many overdrafted groundwater basins that are decoupled from environmental and river flow effects. We argue that, for such cases, a modeling approach that integrates a biophysical response function from a hydrologic model into an economic model of groundwater use is preferable to embedding an economic response function in a complex hydrologic model as is more commonly done. Using this preferred approach, we develop a dynamic hydroeconomic model for the Kings and Tulare Lake subbasins of California and evaluate three groundwater management institutions—open access, perfect foresight, and managed pumping. We quantify the costs and benefits of sustainable groundwater management, including energy pumping savings, drought reserve values, and avoided capital costs. Our analysis finds that, for basins that are severely depleted, losses in crop net revenue are offset by the benefits of energy savings, drought reserve value, and avoided capital costs. This finding provides an empirical counter example to the Gisser and Sanchez Effect.

Hydrogeologic Conceptual Model for the Owens Valley Groundwater Basin (6-12), Inyo and Mono Counties

Inyo County Water Department (ICWD) | January 27th, 2016

This report provides a hydrogeologic conceptual model of the Owens Valley Groundwater Basin (OVGB) compiled from numerous sources including the US Geological Survey, Los

This report provides a hydrogeologic conceptual model of the Owens Valley Groundwater Basin (OVGB) compiled from numerous sources including the US Geological Survey, Los Angeles Department of Water and Power, Inyo and Mono Counties, the California Department of Fish and Wildlife, and the California Department of Water Resources. Because groundwater and surface water systems are linked, both systems are described here, prefaced by a summary of the physical setting of the OVGB.

Hydrogeologic Investigation Arroyo Seco Cone

Monterey County Water Resources Agency (MCWRA) | April 15th, 1994

This report presents the findings, analysis, conclusions, and recommendations developed as part of an investigation to characterize the hydrogeology of the Arroyo Seco Co

This report presents the findings, analysis, conclusions, and recommendations developed as part of an investigation to characterize the hydrogeology of the Arroyo Seco Cone area of the Salinas Valley. The purpose of this investigation is to assess the feasibility of developing a seasonal surface water spreading operation utilizing water diverted from the Arroyo Seco in order to enhance ground water recharge in the area. The goal of a project to store water in the ground for subsequent pumping and use is to increase the yield of the Salinas Basin. This investigation defines the hydrogeologic characteristics of the Arroyo Seco Cone area, characterizes the hydrology of the Arroyo Seco and the availability of divertable flows, and estimates the annual recharge that could be achieved through the development of spreading basins.

Hydrogeology, Hydrologic Effects of Development, and Simulation of Groundwater Flow in the Borrego Valley, San Diego County, California

U.S. Geological Survey (USGS) | November 24th, 2015

The Borrego Valley is a small valley (110 square miles) in the northeastern part of San Diego County, California. Although the valley is about 60 miles northeast of city

The Borrego Valley is a small valley (110 square miles) in the northeastern part of San Diego County, California. Although the valley is about 60 miles northeast of city of San Diego, it is separated from the Pacific Ocean coast by the mountains to the west and is mostly within the boundaries of Anza-Borrego Desert State Park. From the time the basin was first settled, groundwater has been the only source of water to the valley. Groundwater is used for agricultural, recreational, and municipal purposes. Over time, groundwater withdrawal through pumping has exceeded the amount of water that has been replenished, causing groundwater-level declines of more than 100 feet in some parts of the basin. Continued pumping has resulted in an increase in pumping lifts, reduced well efficiency, dry wells, changes in water quality, and loss of natural groundwater discharge. As a result, the U.S. Geological Survey began a cooperative study of the Borrego Valley with the Borrego Water District (BWD) in 2009. The purpose of the study was to develop a greater understanding of the hydrogeology of the Borrego Valley Groundwater Basin (BVGB) and to provide tools to help evaluate the potential hydrologic effects of future development. The objectives of the study were to (1) improve the understanding of groundwater conditions and land subsidence, (2) incorporate this improved understanding into a model that would assist in the management of the groundwater resources in the Borrego Valley, and (3) use this model to test several management scenarios. This model provides the capability for the BWD and regional stakeholders to quantify the relative benefits of various options for increasing groundwater storage. The study focuses on the period 1945–2010, with scenarios 50 years into the future.

Hydrological processes, groundwater recharge and surface-water/groundwater interactions in arid and semi-arid areas

Cambridge University Press (CUP) | December 1st, 2010

The traditional development of water resources in arid areas has relied heavily on the use of groundwater. Groundwater uses natural storage, is spatially distributed and,

The traditional development of water resources in arid areas has relied heavily on the use of groundwater. Groundwater uses natural storage, is spatially distributed and, in climates where potential evaporation rates can be of the order of metres per year, provides protection from the high evaporation losses experienced by surface-water systems. Traditional methods for the exploitation of groundwater have been varied, including the use of very shallow groundwater in seasonally replenished riverbed aquifers (as in the sand rivers of Botswana), the channelling of unconfined alluvial groundwater in afalaj (or qanats) in Oman and Iran, and the use of hand-dug wells. Historically, abstraction rates were limited by the available technology, and rates of development were low, so that exploitation was generally sustainable. However, in recent decades, pump capacities have dramatically increased and hence agricultural use of water has grown rapidly, while the increasing concentration of populations in urban areas has meant that large-scale well fields have been developed for urban water supply. A common picture in arid areas is that groundwater levels are in rapid decline; in many instances this is accompanied by decreasing water quality, particularly in coastal aquifers where saline intrusion is a threat. Associated with population growth, economic development and increased agricultural intensification, pollution has also become an increasing problem. The integrated assessment and management of groundwater resources is essential so that aquifer systems can be protected from pollution and over-exploitation.

Hydrology of the Valley-Fill and Carbonate-Rock Reservoir, Pahrump Valley, Nevada-California

U.S. Geological Survey (USGS) | July 1st, 1967

This is the second appraisal of the water supply of Pahrump Valley, made 15 years after the first cooperative study. In the first report the average recharge was estima

This is the second appraisal of the water supply of Pahrump Valley, made 15 years after the first cooperative study. In the first report the average recharge was estimated to be 23,000 acre-feet per year, only 1,000 acre-feet r^ore than the estimate made in this report. All this recharge was considered to be available for development. Because of the difficulty in salvaging the subsurface outflow from the deep carbonate-rock reservoil', this report concludes that the perennial yield may be only 12,000 acre-feet. In 1875, Bennetts and Manse Springs reportedly discharged a total of nearly 10,000 acre-feet of water from the valley-fill reservoir. After the construction of several flowing wells in 1910, the spring discharge began to decline. In the mid-1940's many irrigation wells were drilled, and large-capacity pumps were installed. During the 4-year period of this study (1959-62), the net pumping draft averaged about 25,000 acre-feet per year, or about twice the estimated yield. In 1962 Bennetts Spring was dry, and the discharge from Marse Spring was only 1,400 acre-feet. During the period February 1959-February 1962, pumping caused an estimated storage depletion of 45,000 acre-feet, or 15,000 acre-feet per year. If the overdraft is maintained, depletion of stored water will continue and pumping costs will increase. Water levels in the vicinity of the Pahrump, Manse, and Fowler Ranches declined more than 10 feet in response to the pumping during this period, and they can be expected to continue to decline at the projected rate of more than 3 feet per year. The chemical quality of the pumped water has been satisfactory for irrigation and domestic use. Recycling of water pumped for irrigation, however, could result in deterioration of the water quality with time.