Groundwater Simulation and Management Models for the Upper Klamath Basin, Oregon and California

U.S. Geological Survey (USGS) | May 5th, 2012

The upper Klamath Basin encompasses about 8,000 square miles, extending from the Cascade Range east to the Basin and Range geologic province in south-central Oregon and n

The upper Klamath Basin encompasses about 8,000 square miles, extending from the Cascade Range east to the Basin and Range geologic province in south-central Oregon and northern California. The geography of the basin is dominated by forested volcanic uplands separated by broad interior basins. Most of the interior basins once held broad shallow lakes and extensive wetlands, but most of these areas have been drained or otherwise modified and are now cultivated. Major parts of the interior basins are managed as wildlife refuges, primarily for migratory waterfowl. The permeable volcanic bedrock of the upper Klamath Basin hosts a substantial regional groundwater system that provides much of the flow to major streams and lakes that, in turn, provide water for wildlife habitat and are the principal source of irrigation water for the basin’s agricultural economy. Increased allocation of surface water for endangered species in the past decade has resulted in increased groundwater pumping and growing interest in the use of groundwater for irrigation. The potential effects of increased groundwater pumping on groundwater levels and discharge to springs and streams has caused concern among groundwater users, wildlife and Tribal interests, and State and Federal resource managers. To provide information on the potential impacts of increased groundwater development, and to aid in the development of a groundwater management strategy, the U.S. Geological Survey, in collaboration with the Oregon Water Resources Department and the Bureau of Reclamation, has developed a groundwater model that can simulate the response of the hydrologic system to these new stresses. The groundwater model was developed using the U.S. Geological Survey MODFLOW finite-difference modeling code and calibrated using inverse methods to transient conditions from 1989 through 2004 with quarterly stress periods. Groundwater recharge and agricultural and municipal pumping are specified for each stress period. All major streams and most major tributaries for which a substantial part of the flow comes from groundwater discharge are included in the model. Groundwater discharge to agricultural drains, evapotranspiration from aquifers in areas of shallow groundwater, and groundwater flow to and from adjacent basins also are simulated in key areas. The model has the capability to calculate the effects of pumping and other external stresses on groundwater levels, discharge to streams, and other boundary fluxes, such as discharge to drains. Historical data indicate that the groundwater system in the upper Klamath Basin fluctuates in response to decadal climate cycles, with groundwater levels and spring flows rising and declining in response to wet and dry periods. Data also show that groundwater levels fluctuate seasonally and interannually in response to groundwater pumping. The most prominent response is to the marked increase in groundwater pumping starting in 2001. The calibrated model is able to simulate observed decadal-scale climate-driven fluctuations in the groundwater system as well as observed shorter-term pumping-related fluctuations. Example model simulations show that the timing and location of the effects of groundwater pumping vary markedly depending on the pumping location. Pumping from wells close (within a few miles) to groundwater discharge features, such as springs, drains, and certain streams, can affect those features within weeks or months of the onset of pumping, and the impacts can be essentially fully manifested in several years. Simulations indicate that seasonal variations in pumping rates are buffered by the groundwater system, and peak impacts are closer to mean annual pumping rates than to instantaneous rates. Thus, pumping effects are, to a large degree, spread out over the entire year. When pumping locations are distant (more than several miles) from discharge features, the effects take many years or decades to fully impact those features, and much of the pumped water comes from groundwater storage over a broad geographic area even after two decades. Moreover, because the effects are spread out over a broad area, the impacts to individual features are much smaller than in the case of nearby pumping. Simulations show that the discharge features most affected by pumping in the area of the Bureau of Reclamation’s Klamath Irrigation Project are agricultural drains, and impacts to other surface-water features are small in comparison. A groundwater management model was developed that uses techniques of constrained optimization along with the groundwater flow model to identify the optimal strategy to meet water user needs while not violating defined constraints on impacts to groundwater levels and streamflows. The coupled groundwater simulation-optimization models were formulated to help identify strategies to meet water demand in the upper Klamath Basin. The models maximize groundwater pumping while simultaneously keeping the detrimental impacts of pumping on groundwater levels and groundwater discharge within prescribed limits. Total groundwater withdrawals were calculated under alternative constraints for 2 Groundwater Simulation and Management Models for the Upper Klamath Basin, Oregon and California drawdown, reductions in groundwater discharge to surface water, and water demand to understand the potential benefits and limitations for groundwater development in the upper Klamath Basin. The simulation-optimization model for the upper Klamath Basin provides an improved understanding of how the groundwater and surface-water system responds to sustained groundwater pumping within the Bureau of Reclamation’s Klamath Project. Optimization model results demonstrate that a certain amount of supplemental groundwater pumping can occur without exceeding defined limits on drawdown and stream capture. The results of the different applications of the model demonstrate the importance of identifying constraint limits in order to better define the amount and distribution of groundwater withdrawal that is sustainable.

Groundwater Sustainability Plan for the Northern and Central Delta-Mendota Regions

San Luis & Delta-Mendota Water Authority (SLDMWA) | November 30th, 2019

Table of Contents Executive Summary Introduction Plan Area Governance and Administration Outreach and Communication Basin Setting Sustainable M

Table of Contents Executive Summary Introduction Plan Area Governance and Administration Outreach and Communication Basin Setting Sustainable Management Criteria Sustainability Implementation Plan Implementation Technical Studies Appendices A. Coordination Agreements B. Common Chapter C. Outreach Documentation D. Water Budget Model Documentation E. Hydrographs for Sustainable Management Criteria F. Quality Assurance Program G. Noticing and Adoption Implementation H. Elements Guide

Guide to Compliance with California’s Sustainable Groundwater Management Act: How to avoid the “undesirable result” of “significant and unreasonable adverse impacts on beneficial uses of surface waters"

Stanford University | September 4th, 2018

In enacting the Sustainable Groundwater Management Act (SGMA) the California Legislature, for the first time ever, expressly linked the two historically distinct legal r

In enacting the Sustainable Groundwater Management Act (SGMA) the California Legislature, for the first time ever, expressly linked the two historically distinct legal regimes governing water in the state that previously had been entirely separate: one governing surface water use and the other groundwater use. SGMA requires Groundwater Sustainability Agencies (GSAs) and their Groundwater Sustainability Plans (GSPs or Plans) to consider and address the groundwater-surface water interaction, and specifically the impacts of groundwater pumping on surface water beneficial uses. SGMA defines sustainable groundwater management as the avoidance of six “undesirable results” identified in the law. The purpose of this guide is to help GSAs and other stakeholders understand and comply with the requirement of SGMA that groundwater withdrawals must not cause “significant and unreasonable adverse impacts on beneficial uses of the surface water,” known as “undesirable result no. 6.” This guide is based on the principle that existing legal frameworks (laws, regulations, court decisions, etc.) provide the clearest and most pertinent guidance on what constitutes undesirable result no. 6. This guide addresses only the explicit legal aspects of this statutory mandate. It does not address technical and scientific aspects of SGMA compliance and offers no advice on the steps GSAs must take to get an adequate technical understanding of the groundwater-surface water connections under their purview. GSAs may look to other sources for guidance on that front. In addition, “Navigating Groundwater-Surface Water Interactions under the Sustainable Groundwater Management Act,” authored by experts at the University of California Berkeley provides a helpful overview of the steps involved in implementing SGMA provisions relating to groundwater-surface water interactions.  

Hudson v. Dailey

Supreme Court of California | December 1st, 1909

Humboldt County | Near-Stream Recharge: Reconnecting Surface and Groundwater

Nature Conservancy | January 1st, 2019

Baker Creek, a tributary to the Mattole River, is a key stream for the federally and state protected coho salmon, however portions of the river were running dry

Baker Creek, a tributary to the Mattole River, is a key stream for the federally and state protected coho salmon, however portions of the river were running dry due to drought, impeding salmon migration and deteriorating habitat. A partnership of federal and state agencies, consultants and NGOs are working to increase groundwater levels with both instream and offchannel projects to ensure year-round water in the creek and floodplain wetlands for salmon habitat. Salmon now returning to the stream, with Phase 1 of the project complete, 1,300 juvenile coho have been counted in Baker Creek after the previous five years saw zero juveniles. Stream restoration in Baker Creek in the Mattole River watershed is an excellent example of a multi- benefit project recharging groundwater, as well as providing the instream coho salmon habitat that has been disappearing.

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.

Hydrogeology of Lower Amargosa Valley and Groundwater Discharge to the Amargosa Wild and Scenic River, Inyo and San Bernardino Counties, California, and Adjacent Areas in Nye and Clark Counties, Nevada

U.S. Geological Survey (USGS) | February 7th, 2019

In 2009, Congress designated certain reaches of the Amargosa River in Inyo County, California between the town of Shoshone and Dumont Dunes as a Wild and Scenic River. As

In 2009, Congress designated certain reaches of the Amargosa River in Inyo County, California between the town of Shoshone and Dumont Dunes as a Wild and Scenic River. As part of the management of the Amargosa Wild and Scenic River, the Bureau of Land Management cooperated with the U.S. Geological Survey to assess the surface and groundwater resources of the Tecopa basin. Groundwater is the primary source of water to the perennial reaches of the Amargosa River. The U.S. Geological Survey studied the surface and groundwater systems in the basin, and assessed the sources and volume of groundwater discharging into the perennial reaches of the Amargosa Wild and Scenic River. The springs within the Tecopa basin (and the greater Lower Amargosa Valley Hydrographic Area) can be generally grouped by spring type and geographic location. There are four types of groundwater discharge points in the Tecopa basin—regional carbonate-rock springs and seeps, Tecopa Hills springs and seeps, thermal springs and seeps, and Amargosa Canyon hillslope springs and seeps. Results of chemical analysis indicate that water from all of these springs in the Lower Amargosa Valley and particularly in the Tecopa basin, is sourced in the carbonate-rock aquifer, with a local component of recharge. Groundwater is recharged in the Spring Mountains and moves through and around the Nopah and Resting Spring Ranges and into the Tecopa basin. A small (less than 1 cubic foot per second [ft3/s] or 500 acre‑feet per year) component of flow from the Amargosa Desert moves through the river channel alluvium and basin fill from the north. The location and type of spring appear to be controlled by the geology and geologic structure of the Lower Amargosa Valley. The regional springs (such as Shoshone and Borax Springs) and associated seeps tend to occur along the west side of the basin whereas other carbonate-rock aquifer springs discharge from adjacent mountain ranges, such as the Resting Spring Range, and as a result of low-permeability barriers, such as the Tecopa Hills. The thermal springs and seeps discharge from an area near the town of Tecopa, California. The Amargosa Canyon hillslope springs and seeps discharge directly into the river. Salt-crusted soils adjacent to the river indicate additional areas of diffuse discharge where groundwater is being evaporated. Perennial flow in the main channel of the Amargosa River appears to originate in an area of thermal springs near Tecopa. Persistent groundwater-fed pools begin to appear along the river channel just to the south of the Tecopa Hills. Flow between these pools is evident, but difficult to measure. During the synoptic seepage measurement survey in February 2014, flow in the Amargosa River at the Tecopa streamgage (U.S. Geological Survey site 10251300, Amargosa River at Tecopa, California) was approximately 1 ft3/s. Just to the south of the Tecopa streamgage, a line of cooler water springs (the Amargosa Canyon hillslope springs) emerges east of the river channel and continues for approximately 1 mile along the Amargosa Canyon wall. At the end of the spring reach, the flow in the river increased to just over 4 ft3/s. Flow then decreased to approximately 3 ft3/s at the confluence of Willow Creek, approximately 3.5 miles downstream. Downstream from the confluence of Willow Creek, the river consistently loses water and was dry just north of Dumont Dunes during the February 2014 synoptic seepage measurement survey.

Hydrologic and Geochemical Characterization of the Santa Rosa Plain Watershed, Sonoma County, California

U.S. Geological Survey (USGS) | July 9th, 2013

The Santa Rosa Plain is home to approximately half of the population of Sonoma County, California, and faces growth in population and demand for water. Water managers are

The Santa Rosa Plain is home to approximately half of the population of Sonoma County, California, and faces growth in population and demand for water. Water managers are confronted with the challenge of meeting the increasing water demand with a combination of water sources, including local groundwater, whose future availability could be uncertain. To meet this challenge, water managers are seeking to acquire the knowledge and tools needed to understand the likely effects of future groundwater development in the Santa Rosa Plain and to identify efficient strategies for surface- and groundwater management that will ensure the long-term viability of the water supply. The U.S. Geological Survey, in cooperation with the Sonoma County Water Agency and other stakeholders in the area (cities of Cotati, Rohnert Park, Santa Rosa, and Sebastopol, town of Windsor, Cal-American Water Company, and the County of Sonoma), undertook this study to characterize the hydrology of the Santa Rosa Plain and to develop tools to better understand and manage the groundwater system. The objectives of the study are: (1) to develop an updated assessment of the hydrogeology and geochemistry of the Santa Rosa Plain; (2) to develop a fully coupled surface-water and groundwater-flow model for the Santa Rosa Plain watershed; and (3) to evaluate the potential hydrologic effects of alternative groundwater-management strategies for the basin. The purpose of this report is to describe the surface-water and groundwater hydrology, hydrogeology, and water-quality characteristics of the Santa Rosa Plain watershed and to develop a conceptual model of the hydrologic system in support of the first objective. The results from completing the second and third objectives will be described in a separate report.

Hydrologic Model of the Modesto Region, California, 1960–2004

U.S. Geological Survey (USGS) | June 1st, 2015

Strategies for managing water supplies and groundwater quality in the Modesto region of the eastern San Joaquin Valley, California, are being formulated and evaluated by

Strategies for managing water supplies and groundwater quality in the Modesto region of the eastern San Joaquin Valley, California, are being formulated and evaluated by the Stanislaus and Tuolumne Rivers Groundwater Basin Association. Management issues and goals in the basin include an area in the lower part of the basin that requires drainage of the shallow water table to sustain agriculture, intra- and inter-basin migration of poor-quality groundwater, and efficient management of surface and groundwater supplies. To aid in the evaluation of water-management strategies, the U.S. Geological Survey and the Stanislaus and Tuolumne Rivers Groundwater Basin Association have developed a hydrologic model that simulates monthly groundwater and surface-water flow as governed by aquifer-system properties, annual and seasonal variations in climate, surface-water flow and availability, water use, and land use. The model was constructed by using the U.S. Geological Survey groundwater-modeling software MODFLOW-OWHM with the Farm Process. Available measurements of groundwater pumped for municipal, irrigation, and drainage purposes are specified in the model, as are deliveries of surface water. Private irrigation pumping and recharge associated with agricultural land use were estimated by using the Farm Process in MODFLOW-OWHM, which simulates landscape processes associated with irrigated agriculture and other land uses. The distribution of hydraulic conductivity in the aquifer system was constrained by using data from more than 3,500 drillers’ logs. The model was calibrated to 4,061 measured groundwater levels in 109 wells and 2,739 mean monthly surface-water flows measured at 6 streamgages during 1960–2004 by using a semi-automated method of parameter estimation. The model fit to groundwater levels was good, with an absolute mean residual of 0.8 feet; 74 percent of simulated heads were within 10 feet of those observed. The model fit to streamflow was biased low, but reasonable overall; the absolute mean residual of streamflow was 780 cubic feet per second, and 68 percent of simulated streamflows were within 500 cubic feet per second of observed. Hydrographs both of groundwater levels and streamflow indicated overall an acceptable fit to observed trends. Simulated private agricultural pumpage ranged from about 780,000 to 1,380,000 acre-feet per year and averaged about 1,000,000 acre-feet per year from 1960 to 2004. Simulated deep percolation, or groundwater recharge from precipitation and irrigation, varied with climate and land use from about 1,100,000 to 1,700,000 acre-feet per year, averaging 1,360,000 acre-feet per year. Key limitations of the model with respect to estimating these large components of the water budget are the uncertainty associated with actual irrigation deliveries and irrigation efficiencies and the lack of metered data for private agricultural groundwater pumping. Different assumptions with respect to irrigation deliveries and efficiencies, and other model input, would result in different estimates of private agricultural groundwater use. The simulated exchange between groundwater and surface water was a small percentage of streamflow, typically ranging within a loss or gain of about 2 cubic feet per second per mile. The simulated exchange compared reasonably with limited independent estimates available, but substantial uncertainty is associated with these estimates.

Indigenous communities, groundwater opportunities

American Association for the Advancement of Science (AAAS) | August 3rd, 2018

Instead of managing fresh water as one integrated resource, laws frequently treat groundwater separately from more visible, monitored, and managed surface waters. One und

Instead of managing fresh water as one integrated resource, laws frequently treat groundwater separately from more visible, monitored, and managed surface waters. One under-recognized consequence of such legal fragmentation has been uncertainty about whether water rights for indigenous communities, which have been addressed in many countries to varying degrees for surface waters, apply to groundwater. In late 2017, the U.S. Supreme Court left standing a lower court ruling endorsing priority groundwater rights for Native American tribes by denying an appeal in Agua Caliente Band v. Coachella Valley Water District. This ruling establishes a new standard throughout nine western states within the lower court's jurisdiction and establishes persuasive, although nonbinding, legal precedent for the rest of the United States. To evaluate the ruling's broader potential impacts, we present new data cataloging existing Native American water rights and mapping unresolved tribal groundwater claims across the western United States. No court considered such a regional or national quantitative catalog or map. Drawing lessons from past U.S. experience, we then discuss how tribal rights may offer new opportunities to achieve sustainable groundwater management for society at large, with implications beyond the United States. *The full text of this paper is behind a Science Magazine pay wall at a single-issue cost of $15. It should be available for free through research portals at universities, and may be accessible through public libraries with Science Magazine subscriptions. A free summary is contained by the August 3, 2018 Stanford News report "Stanford study reveals the changing scope of Native American groundwater rights – and opportunities for better freshwater management."