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Green Light for Adaptive Policies on the Colorado River

Water (MDPI) | December 21st, 2021

Summary

The Colorado River is a critical source of water supply for 40 million people in nine states spanning two nations in western North America. Overallocated in the 20th cent

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Ground Water in the Redding Basin, Shasta and Tehama Counties, California

U.S. Geological Survey (USGS) | December 31st, 1983

Summary

The Redding Basin covers about 510 square miles in the northern part of the Central Valley of California and is surrounded by the Cascade Range, Klamath Mountains,and Coa

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Ground-water conditions at Beale Air Force Base and vicinity, California

U.S. Geological Survey (USGS) | April 15th, 1980

Summary

The U.S. Geological Survey was asked by the Air Force to make a study of ground-water conditions at the base. This report and an earlier data report have resulted

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Ground-Water Hydrology of the Upper Klamath Basin, Oregon and California

U.S. Geological Survey (USGS) | April 15th, 2010

Summary

The upper Klamath Basin spans the California-Oregon border from the flank of the Cascade Range eastward to the Basin and Range Province, and encompasses the Klamath River

The upper Klamath Basin spans the California-Oregon border from the flank of the Cascade Range eastward to the Basin and Range Province, and encompasses the Klamath River drainage basin above Iron Gate Dam. Most of the basin is semiarid, but the Cascade Range and uplands in the interior and eastern parts of the basin receive on average more than 30 inches of precipitation per year. The basin has several perennial streams with mean annual discharges of hundreds of cubic feet per second, and the Klamath River at Iron Gate Dam, which represents drainage from the entire upper basin, has a mean annual discharge of about 2,100 cubic feet per second. The basin once contained three large lakes: Upper and Lower Klamath Lakes and Tule Lake, each of which covered areas of 100 to 150 square miles, including extensive marginal wetlands. Lower Klamath Lake and Tule Lake have been mostly drained, and the former lake beds are now cultivated. Upper Klamath Lake remains, and is an important source of irrigation water. Much of the wetland surrounding Upper Klamath Lake has been diked and drained, although efforts are underway to restore large areas. Upper Klamath Lake and the remaining parts of Lower Klamath and Tule Lakes provide important wildlife habitat, and parts of each are included in the Klamath Basin National Wildlife Refuges Complex. The upper Klamath Basin has a substantial regional ground-water flow system. The late Tertiary to Quaternary volcanic rocks that underlie the region are generally permeable, with transmissivity estimates ranging from 1,000 to 100,000 feet squared per day, and compose a system of variously interconnected aquifers. Interbedded with the volcanic rocks are late Tertiary sedimentary rocks composed primarily of fine-grained lake sediments and basin-filling deposits. These sedimentary deposits have generally low permeability, are not good aquifers, and probably restrict ground-water movement in some areas. The regional ground-water system is underlain and bounded on the east and west by older Tertiary volcanic and sedimentary rocks that have generally low permeability. Eight regional-scale hydrogeologic units are defined in the upper Klamath Basin on the basis of surficial geology and subsurface data. Ground water flows from recharge areas in the Cascade Range and upland areas in the basin interior and eastern margins toward stream valleys and interior subbasins. Ground water discharges to streams throughout the basin, and most streams have some component of ground water (baseflow). Some streams, however, are predominantly ground-water fed and have relatively constant flows throughout the year. Large amounts of ground water discharge in the Wood River subbasin, the lower Williamson River area, and along the margin of the Cascade Range. Much of the inflow to Upper Klamath Lake can be attributed to ground-water discharge to streams and major spring complexes within a dozen or so miles from the lake. This large component of ground water buffers the lake somewhat from climate cycles. There are also ground-water discharge areas in the eastern parts of the basin, for example in the upper Williamson and Sprague River subbasins and in the Lost River subbasin at Bonanza Springs. Irrigated agriculture is an integral part of the economy of the upper Klamath Basin. Although estimates vary somewhat, roughly 500,000 acres are irrigated in the upper Klamath Basin, about 190,000 acres of which are part of the Bureau of Reclamation Klamath Project. Most of this land is irrigated with surface water. Ground water has been used for many decades to irrigate areas where surface water is not available, for example outside of irrigation districts and stream valleys. Ground water has also been used as a supplemental source of water in areas where surface water supplies are limited and during droughts. Ground water use for irrigation has increased in recent years due to drought and shifts in surface-water allocation from irrigation to instream uses. The shifts in surface-water allocation have resulted from efforts to improve habitat for fish listed under the Federal Endangered Species Act. The ground-water system in the upper Klamath Basin responds to external stresses such as climate cycles, pumping, lake stage variations, and canal operation. This response is manifest as fluctuations in hydraulic head (as represented by fluctuations in the water-table surface) and variations in ground-water discharge to springs. Basinwide, decadal-scale climate cycles are the largest factor controlling head and discharge fluctuations. Climate-driven water-table fluctuations of more than 12 feet have been observed near the Range, and decadal-scale fluctuations of 5 feet are common throughout the basin. Ground-water discharge to springs and streams varies basinwide in response to decadal-scale climate cycles. The response of the ground-water system to pumping is generally largest in areas where pumping occurs. Annual drawdown and recovery cycles of 1 to 10 feet are common in pumping areas. Long-term drawdown effects, where the water table has reached or is attempting to reach a new level in equilibrium with the pumping, are apparent in parts of the basin. Since 2001, ground-water use in the upper Klamath Basin has increased by about 50 percent. Much of this increase has occurred in the area in and around the Bureau of Reclamation Klamath Project, roughly tripling ground-water pumping in that area. This focused increase in pumping has resulted in ground-water level declines in the pumped aquifer in excess of 10 to 15 feet over a large part of the Project between 2001 and 2004. If pumping rates of recent years are continued, the aquifer could achieve a new equilibrium; however, the final configuration of the water table (depth to water) and the spatial and temporal distribution of the resulting effects to streams are unknown. Historical water-level data suggest that the water table should recover from recent declines if pumping is reduced to pre-2001 rates.

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Ground-Water Resources of Honey Lake Valley, Lassen County, California, and Washoe County, Nevada

U.S. Geological Survey (USGS) | December 15th, 1990

Summary

Honey Lake Valley is a 2,200-square-mile, northwest-trending, topographically closed basin about 35 miles northwest of Reno, Nevada. Unconsolidated basin-fill deposits on

Honey Lake Valley is a 2,200-square-mile, northwest-trending, topographically closed basin about 35 miles northwest of Reno, Nevada. Unconsolidated basin-fill deposits on the valley floor and fractured volcanic rocks in the northern and eastern uplands are the principal aquifers. Ground water in the Nevada part of the basin is being considered as a potential source of public supply to the Reno area. This report describes the ground-water resources of the basin and the potential hydrologic effects of ground-water development in its eastern part. During an average year, about 1.1 million acre-feet of precipitation falls on the 1,700-square-mile study area within the valley, and an estimated 86,000 acre-feet enters the study area as streamflow in the Susan River and Long Valley Creek. Almost 90 percent of this water runs off, evaporates, or is transpired by plants before it can infiltrate and become ground-water recharge; this includes about 130,000 acre-feet per year that reaches Honey Lake as surface-water inflow. About 130,000 acre-feet recharges the aquifer system annually, about 40 percent by direct infiltration of precipitation over the study area and about 60 percent by infiltration of streamflow and irrigation water. Balancing this is an equal amount of ground-water discharge, of which about 65 percent evaporates from the water table or is transpired by phreatophytes, about 30 percent is withdrawn from wells, and about 5 percent leaves the basin as subsurface outflow to the east. A ground-water flow model of the eastern part of the study area, where withdrawals for public supply have been proposed, was used to evaluate components of the water budget and to estimate the long-term hydrologic effects of hypothetical increased development. Results of the evaluation indicate conditions under which a new equilibrium would be established if 15,000 acre-feet of water were withdrawn from the Fish Springs Ranch area annually. The model indicates that, as a result of such an increase in pumpage, water levels would decline more than 100 feet from present (1988) levels in the vicinity of the pumping, and as much as 40 feet at the California-Nevada State line. Evapotranspiration and subsurface outflow to the east would each be reduced by about 60 percent, but hydrologic effects would be minimal at the western boundary of the flow-model area (just east of Honey Lake). Within the modeled area, the simulation indicates that the increased withdrawals would cause the net flow of ground water eastward across the State line to increase from about 700 acre-feet per year to about 2,300 acre-feet per year.

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Groundwater and Stream Interaction in California's Central Valley: Insights for Sustainable Groundwater Management

Nature Conservancy | June 16th, 2016

Summary

Sustainable water management requires ensuring ecosystem water needs are met in balance with water needs for people. The Nature Conservancy (TNC) is working across Califo

Sustainable water management requires ensuring ecosystem water needs are met in balance with water needs for people. The Nature Conservancy (TNC) is working across California to demonstrate how to achieve this balance in the context of integrated water management programs. Sustainable water management must also recognize that surface water and groundwater resources are interconnected and that proper management of these resources includes understanding this interaction and managing the resources accordingly. Management of groundwater and surface water systems in an integrated manner is impeded by California water law and policy, which has separate rules and regulations for managing groundwater and surface water resources. The Central Valley of California is the hub of the state’s water supply system. An extensive network of dams and canals supplies surface water to users within the Central Valley as well as to the San Francisco Bay Area, the Central Coast, and Southern California. Analysis of information collected in this study reveals that just within the Central Valley, agricultural and urban sectors use an average of 13 million acre-feet (MAF) of surface water and over 8 MAF of groundwater per year. Approximately 2 MAF of water is exported annually to areas outside the Central Valley. Because the availability of surface water supplies varies significantly from year to year, groundwater use also varies considerably on annual basis. In an average year, groundwater meets about 40% of the state’s water demand and up to 60% or more during droughts, when groundwater provides a water supply buffer against economic and environmental harm from water scarcity (DWR, 2014). In some areas, groundwater provides 100% of the supply, even in wetter years, and then is heavily pumped during drought. In other locations, where surface water supplies are reasonably abundant, groundwater use may be relatively light during wetter years, but more heavily pumped during drier years when surface water supplies are cut back. Accordingly, the impact of groundwater use is much more evident during dry years, and especially in drought conditions. A case in point is the drought condition of 2013-15. This drought is exerting significant stress on the state’s water supply. The surface water deliveries have been reduced dramatically, to near zero in many regions; therefore, agricultural and municipal water users in the Central Valley and other parts of the state that normally rely on surface water for much of their supplies, are now greatly increasing their use of groundwater to meet their needs. A 2014 UC Davis report indicates that expected increase in Central Valley groundwater pumping would be in the range of 20% to 25%, during the 2014 irrigation season. To the authors’ knowledge, there are no reports of actual estimates of increase in groundwater use for the recent drought conditions. The long-term increase in groundwater pumping and especially recent drought related increases in pumping would translate into significantly more adverse impacts on the surface water and stream systems, as well as groundwater dependent ecosystems. In addition, this increase in groundwater pumping could potentially result in more land subsidence throughout the valley. The drought has also affected the irrigated lands under cultivation. A November 2014 DWR publication “Public Update for Drought Response” 3 reported that based on NASA satellite imagery, approximately 700,000 acres of land were estimated idled between 2011 and 2014. Majority of these acreages idled are reported to be due to the drought conditions, although, some were also due to normal agronomic practices, crop markets, and other reasons. This report provides the results of a number of analyses and evaluations of Central Valley hydrologic conditions using the California Central Valley Groundwater-Surface Water Simulation Model (C2VSim). The study examines important hydrologic and operational characteristics and behaviors of the California’s Central Valley water system during the historical development in the Valley. In addition, the study presents results of model simulations conducted to assess potential impacts of several water management scenarios. The results of this study contribute significantly to the understanding of how management of groundwater and surface water are interrelated and will inform the development of more effective integrated water management in the Central Valley and throughout California. The interaction between groundwater and surface water resources has been evaluated and illustrated by many researchers. As early as 1941, Theis (1941) documented the hydraulic connection between stream and aquifer systems and quantitatively described the general behavior of stream-groundwater systems. Many others, including Glover & Balmer (1954) and Hantush (1965) built on Theis’ work, which demonstrated and confirmed the basic principles of hydraulic connection between stream and aquifer systems. In recent years, significant work has been conducted regarding regional impacts of groundwater pumping and operation on regional surface water systems. For example, the recent USGS study (Barlow & Leake, 2012) presents original findings of the stream-aquifer interaction in the context of sustainable groundwater management. In an effort to quantify the interaction between the groundwater and the surface water system, DWR’s C2VSim model was employed in this study. The C2VSim model was originally developed in 1990 for DWR, U. S. Bureau of Reclamation (USBR), and California State Water Resources Control Board (SWRCB) as the Central Valley Groundwater and Surface water Model (CVGSM) (James M. Montgomery Consulting Engineers, 1990a). Subsequently, the model was enhanced through numerous key applications, including the Central Valley Project Improvement Act – Programmatic Environmental Impact Statement (CVPIA-PEIS). In 2005, the CVGSM model was upgraded to the newly developed Integrated Water Flow Model (IWFM) platform, and was renamed the C2VSim model. The detailed features of the model are described and presented in Section 2 of this report. The C2VSim model is a leading Central Valley-wide integrated hydrologic model adopted by DWR and many other regional and state-wide agencies, as well as non-governmental organizations (NGOs) to evaluate various water management scenarios throughout the Valley. This report is organized in six sections: Section 1: Provides the background information and lays out the goals and objectives of this study. Section 2: Provides information on the status of C2VSim model, refinements made during this study, and assumptions on the modeling analysis. Section 3: Discusses simulation of the historical hydrologic conditions in the Central Valley. Section 4: Provides the assumptions and results of the existing baseline conditions, assuming that no changes to the facilities and their operations, as well as water management actions, take place over the course of a predetermined hydrologic condition. Section 5: Provides a description of three water management scenarios that may have major impacts on the future of surface water and groundwater interaction in Central Valley. Results of simulation of these management scenarios are presented and discussed in detail. Section 6: Provides conclusions from this study and a list of recommendations for future work.

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Groundwater and Urban Growth in the San Joaquin Valley

Public Policy Institute of California (PPIC) | September 20th, 2021

Summary

The San Joaquin Valley is ground zero for the Sustainable Groundwater Management Act (SGMA). It has the largest groundwater deficit in California and faces some of the

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Groundwater Availability of the Central Valley Aquifer

U.S. Geological Survey (USGS) | July 15th, 2009

Summary

California’s Central Valley covers about 20,000 square miles and is one of the most productive agricultural regions in the world. More than 250 different crops are grow

California’s Central Valley covers about 20,000 square miles and is one of the most productive agricultural regions in the world. More than 250 different crops are grown in the Central Valley with an estimated value of $17 billion per year. This irrigated agriculture relies heavily on surface-water diversions and groundwater pumpage. Approximately one-sixth of the Nation’s irrigated land is in the Central Valley, and about one-fifth of the Nation’s groundwater demand is supplied from its aquifers. The Central Valley also is rapidly becoming an important area for California’s expanding urban population. Since 1980, the population of the Central Valley has nearly doubled from 2 million to 3.8 million people. The Census Bureau projects that the Central Valley’s population will increase to 6 million people by 2020. This surge in population has increased the competition for water resources within the Central Valley and statewide, which likely will be exacerbated by anticipated reductions in deliveries of Colorado River water to southern California. In response to this competition for water, a number of water-related issues have gained prominence: conservation of agricultural land, conjunctive use, artificial recharge, hydrologic implications of land-use change, and effects of climate variability. To provide information to stakeholders addressing these issues, the USGS Groundwater Resources Program made a detailed assessment of groundwater availability of the Central Valley aquifer system, that includes: (1) the present status of groundwater resources; (2) how these resources have changed over time; and (3) tools to assess system responses to stresses from future human uses and climate variability and change. This effort builds on previous investigations, such as the USGS Central Valley Regional Aquifer System and Analysis (CV-RASA) project and several other groundwater studies in the Valley completed by Federal, State and local agencies at differing scales. The principal product of this new assessment is a tool referred to as the Central Valley Hydrologic Model (CVHM) that accounts for integrated, variable water supply and demand, and simulates surface-water and groundwater-flow across the entire Central Valley system. The development of the CVHM comprised four major elements: (1) a comprehensive Geographic Information System (GIS) to compile, analyze and visualize data; (2) a texture model to characterize the aquifer system;(3) estimates of water-budget components by numerically modeling the hydrologic system with the Farm Process (FMP); and (4) simulations to assess and quantify hydrologic conditions. Chapter A: Introduction, Overview of Hydrogeology, and Textural Model of California’s Central Valley Chapter B: Groundwater Availability in California’s Central Valley Chapter C: Numerical Model of the Hydrologic Landscape and Groundwater Flow in California’s Central Valley Appendix 1: Supplemental Information—Modifications to Modflow-2000 Packages and Processes

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Groundwater Basins in California

California Department of Water Resources (DWR) | November 1st, 1952

Summary

Section 229 of the Water Code directs that the California Department of Public Works, acting by and through the State Engineer, shall "investigate conditions of the quali

Section 229 of the Water Code directs that the California Department of Public Works, acting by and through the State Engineer, shall "investigate conditions of the quality of all the waters within the State, including saline waters, coastal and inland, as related to all sources of pollution of whatever nature and shall report thereon to the Legislature and to the appropriate regional water pollution control board annually, and may recommend any steps which might be taken to improve or protect the quality of such waters." In order to carry out the intent of Section 228 of the Water Code with respect to investigations of quality of ground waters within the State, it has been necessary first to compile available geologic data in order to locale and define the approximate boundaries of the more important ground water basins. A base index map showing the principal areas of groundwater storage in the State of California has not been previously prepared. Such a map has been complied for this report in order to establish a uniform name and numbering system for groundwater basins, which can be expanded as new areas of ground water storage are identified, or as it is found necessary to divide the larger areas into subbasins. It will serve as a basis for the planning of future investigations of the groundwater resources of California. This report identifies alluvial or valley fill areas which contain the principal groundwater resources in California. However, the report is necessarily not complete because of lack of information for many areas of the state. In general, the areas of groundwater storage indentified include: (a) the major alluvium-filled areas of known groundwater storage and extraction; (b) the extensive areas of alluvial-fill in the Colorado, Mojave, and Basin and Range desert areas which may contain usable groundwater, though little is known of their storage capacity or recharge; and (c) some of the smaller alluvium-filled areas which may furnish a portion of local domestic, irrigation, municipal, and industrial water supplies.

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Groundwater depletion in California’s Central Valley accelerates during megadrought

Nature Portfolio (Springer Nature) | December 19th, 2022

Summary

Groundwater provides nearly half of irrigation water supply, and it enables resilience during drought, but in many regions of the world, it remains poorly, if at all mana

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Green Light for Adaptive Policies on the Colorado River

Ground Water in the Redding Basin, Shasta and Tehama Counties, California

Ground-water conditions at Beale Air Force Base and vicinity, California

Ground-Water Hydrology of the Upper Klamath Basin, Oregon and California

Ground-Water Resources of Honey Lake Valley, Lassen County, California, and Washoe County, Nevada

Groundwater and Stream Interaction in California's Central Valley: Insights for Sustainable Groundwater Management

Groundwater and Urban Growth in the San Joaquin Valley

Groundwater Availability of the Central Valley Aquifer

Groundwater Basins in California

Groundwater depletion in California’s Central Valley accelerates during megadrought

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