Incomplete Determination for Groundwater Sustainability Plan submitted for Owens Valley Subbasin (Basin No. 6-012.01)

California Department of Water Resources (DWR) | April 14th, 2025

Incomplete Determination of the 2020 Eastern San Joaquin Subbasin Groundwater Sustainability Plan

California Department of Water Resources (DWR) | January 28th, 2022

The Department of Water Resources (Department) has evaluated the groundwater sustainability plan (GSP) submitted for the Eastern San Joaquin Subbasin (Subbasin) and has d

The Department of Water Resources (Department) has evaluated the groundwater sustainability plan (GSP) submitted for the Eastern San Joaquin Subbasin (Subbasin) and has determined that the GSP is incomplete. The Department based its determination on recommendations from the Staff Report, included as an enclosure to the attached Statement of Findings, which describes that the Eastern San Joaquin Subbasin GSP does not satisfy the objectives of the Sustainable Groundwater Management Act (SGMA) nor substantially comply with the GSP Regulations. The Staff Report also provides corrective actions which the Department recommends to address the identified deficiencies.

Indian Wells Valley Groundwater Basin Groundwater Sustainability Plan

Indian Wells Valley Groundwater Authority (IWVGA) | January 14th, 2020

Currently, the groundwater resources in the Indian Wells Valley Groundwater Basin (IWVGB or Basin) are not being sustainably managed. Overdraft conditions have existed fo

Currently, the groundwater resources in the Indian Wells Valley Groundwater Basin (IWVGB or Basin) are not being sustainably managed. Overdraft conditions have existed for decades as a result of groundwater pumping that exceeds the natural Basin yield (Dutcher and Moyle, 1973). The results of overdraft have manifested themselves through various undesirable results, primarily the chronic lowering of groundwater levels, the degradation of water quality, and the reduction of groundwater in storage throughout the IWVGB. (See Section 3 for a discussion of overdraft conditions in the Basin.) In compliance with the Sustainable Groundwater Management Act (SGMA), as set forth in California Water Code (CWC) Section 10720.1, this Groundwater Sustainability Plan (GSP) discusses Basin management strategies that will culminate in the absence of undesirable and unsustainable groundwater conditions in the IWVGB. The GSP recommends management actions and projects, and provides measurable sustainability objectives and milestones that are intended to achieve Basin sustainability while considering the unique geologic and hydrogeologic conditions of the IWVGB. The recommendations of this GSP will provide for long-term sustainable groundwater management in the IWVGB within 20 years of GSP implementation. Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7

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."    

Influence of agricultural managed aquifer recharge on nitrate transport: The role of soil texture and flooding frequency

Soil Science Society of America (SSSA) | June 9th, 2021

Agricultural managed aquifer recharge (Ag-MAR) is a concept in which farmland is flooded during the winter using excess surface water to recharge the underlying groundwat

Agricultural managed aquifer recharge (Ag-MAR) is a concept in which farmland is flooded during the winter using excess surface water to recharge the underlying groundwater. In this study, we show how different recharge practices affect NO3− leaching and mineralization–denitrification processes in different soil systems. Two contrasting soil textures (sand and fine sandy loam) from the Central Valley, Califor- nia, were repeatedly flooded with 15 cm of water at varying time intervals in field and soil column experiments. Nitrogen species (NO3–, NH4+, total N), total C, dis- solved O2, and moisture content were measured throughout the experiments. Results show that when flooding occurs at longer intervals (every 1–2 wk), N mineralization increases, leading to an increase of mobile NO3− in the upper root zone and leach- ing of significant quantities of NO3− from both soil textures (137.3 ± 6.6% [sand] and 145.7 ± 5.8% [fine sandy loam] of initial residual soil NO3−) during subsequent flooding events. Laboratory mineralization incubations show that long flooding inter- vals promote mineralization and production of excess NO3− at rates of 0.11–3.93 mg N kg–1 wk–1 (sand) and 0.08–3.41 mg N kg–1 wk–1 (fine sandy loam). Decreasing the flooding frequency to 72 h reduces potential mineralization, decreasing the amount of NO3− leached during flooding events (31.7 ± 3.8% [sand] and 64.7 ± 10.4% [fine sandy loam] of initial residual soil NO3–). The results indicate that implementing recharge as repeated events over a long (multiple-week) time horizon might increase the total amount of NO3− potentially available for leaching to groundwater.

Integrated Hydrologic Model of Pajaro Valley, Santa Cruz and Monterey Counties, California

U.S. Geological Survey (USGS) | September 5th, 2014

Increasing population, agricultural development (including shifts to more water-intensive crops), and climate variability are placing increasingly larger demands on avail

Increasing population, agricultural development (including shifts to more water-intensive crops), and climate variability are placing increasingly larger demands on available groundwater resources in the Pajaro Valley, one of the most productive agricultural regions in the world. This study provided a refined conceptual model, geohydrologic framework, and integrated hydrologic model of the Pajaro Valley. The goal of this study was to produce a model capable of being accurate at scales relevant to water management decisions that are being considered in the revision and updates to the Basin Management Plan (BMP). The Pajaro Valley Hydrologic Model (PVHM) was designed to reproduce the most important natural and human components of the hydrologic system and related climatic factors, permitting an accurate assessment of groundwater conditions and processes that can inform the new BMP and help to improve planning for long-term sustainability of water resources. Model development included a revision of the conceptual model of the flow system, reevaluation of the previous model transformed into MODFLOW, implementation of the new geohydrologic model and conceptual model, and calibration of the transient hydrologic model. The conceptual model identified inflows and outflows that include the movement and use of water from natural and human components. The groundwater flow system is characterized as a layered geologic sedimentary system through which downward flow is driven by the combined effects of the application of irrigation water at the land surface and the pumping of groundwater from deeper in the system. Overall, groundwater meets most of the agricultural demand in the initial part of the growing season, augmented by precipitation during wet winter and spring seasons. In addition, the amount of groundwater used for irrigation varies from year to year in response to climate variation and can increase dramatically in dry years. Data on agricultural pumpage is a major component of simulated outflow that was previously unavailable; therefore, a coupled farm-process model was used to estimate historical pumpage for Pajaro Valley by subregion (water-balance subregions) as well as the delivery of surface water to and from the Harkins Slough Aquifer-Storage-and-Recovery System (HS-ASR) and related Coastal Distribution System (CDS) since 2002. The new, integrated hydrologic model includes new water-balance subregions; delineation of natural, municipal, and agricultural land use; streamflow networks; regions of tile drains; and, the groundwater flow system. The redefinition of the geohydrologic framework and incorporation into the simulation revealed the importance of the confining units at the base of the alluvial deposits and between the upper and lower Aromas Sand for regional groundwater flow.

Integrated Surface and Groundwater Modeling of Martis Valley, California, for Assessment of Potential Climate Change Impacts on Basin-Scale Water Resources

U.S. Bureau of Reclamation (USBR) | April 15th, 2015

This study develops a modeling framework to better understand surface and groundwater interactions in the Martis Valley Basin. Prior to the current study there were no ph

This study develops a modeling framework to better understand surface and groundwater interactions in the Martis Valley Basin. Prior to the current study there were no physical or statistical models of the Martis Valley Basin that could be used for long term water resource planning in the Basin. Currently, groundwater is the primary source for municipal and industrial water supply in Martis Valley, and surface water from the surrounding watersheds are partly stored in Donner, Prosser reservoirs and allowed to runoff into the Truckee River. This study presents the development, calibration, and verification of the physically based surface and groundwater GSFLOW model for Martis Valley. The model was calibrated for the historical 1981-2011 observed period. Various observations were used to calibrate the model during different periods, which helped verify the model’s ability to capture the dynamics of the hydrologic system. The model was calibrated to multiple fluxes and states in the hydrological system including streamflow, snow water equivalent, groundwater heads, and wetland and spring locations. In addition to comparing fluxes to multiple observations, consistency at internal gauges was also verified apart from simulating fluxes at the outlet. For future projections of hydrology, the GSFLOW model was forced with five future climate scenarios provided by CH2M HILL. Future simulations of snow water equivalent indicate reductions for all scenarios due to increasing temperatures. Groundwater recharge and its contribution to streamflow also decrease in the future for the warmer drier and hotter drier scenarios. The reduction in snowpack and earlier melt complicates the seasonally dependent nature of water resources and when combined, these results will likely add further stress to long term water availability in the Martis Valley Basin and the downstream consumers of the waters generated in the Basin.

Interbasin flow in the Great Basin with special reference to the southern Funeral Mountains and the source of Furnace Creek springs, Death Valley, California, U.S.

Journal of Hydrology (Elsevier) | May 5th, 2009

Interbasin flow in the Great Basin has been established by scientific studies during the past century. While not occurring uniformly between all basins, its occurrence is

Interbasin flow in the Great Basin has been established by scientific studies during the past century. While not occurring uniformly between all basins, its occurrence is common and is a function of the hydraulic gradient between basins and hydraulic conductivity of the intervening rocks. The Furnace Creek springs in Death Valley, California are an example of large volume springs that are widely accepted as being the discharge points of regional interbasin flow. The flow path has been interpreted historically to be through consolidated Paleozoic carbonate rocks in the southern Funeral Mountains. This work reviews the preponderance of evidence supporting the concept of interbasin flow in the Death Valley region and the Great Basin and addresses the conceptual model of pluvial and recent recharge [Nelson, S.T., Anderson, K., Mayo, A.L., 2004. Testing the interbasin flow hypothesis at Death Valley, California. EOS 85, 349; Anderson, K., Nelson, S., Mayo, A., Tingey, D., 2006. Interbasin flow revisited: the contribution of local recharge to high-discharge springs, Death Valley, California. Journal of Hydrology 323, 276–302] as the source of the Furnace Creek springs. We find that there is insufficient modern recharge and insufficient storage potential and permeability within the basin-fill units in the Furnace Creek basin for these to serve as a local aquifer. Further, the lack of high sulfate content in the spring waters argues against significant flow through basin-fill sediments and instead suggests flow through underlying consolidated carbonate rocks. The maximum temperature of the spring discharge appears to require deep circulation through consolidated rocks; the Tertiary basin fill is of insufficient thickness to generate such temperatures as a result of local fluid circulation. Finally, the stable isotope data and chemical mass balance modeling actually support the interbasin flow conceptual model rather than the alternative presented in Nelson et al. [Nelson, S.T., Anderson, K., Mayo, A.L., 2004. Testing the interbasin flow hypothesis at Death Valley, California. EOS 85, 349] and Anderson et al. [Anderson, K., Nelson, S., Mayo, A., Tingey, D., 2006. Interbasin flow revisited: the contribution of local recharge to high-discharge springs, Death Valley, California. Journal of Hydrology 323, 276– 302]. In light of these inconsistencies, interbasin flow is the only readily apparent explanation for the large spring discharges at Furnace Creek and, in our view, is the likely explanation for most large volume, low elevation springs in the Great Basin. An understanding of hydrogeologic processes that control the rate and direction of ground-water flow in eastern and central Nevada is necessary component of regional water-resource planning and management of alluvial and bedrock aquifers.

Investigating the Link Between Surface Water and Groundwater in the Tule Lake Subbasin, Oregon and California

Portland State University | August 13th, 2014

Water allocation in the upper Klamath Basin of Oregon and California has been challenging. Irrigators have increasingly turned to groundwater to make up for surf

Water allocation in the upper Klamath Basin of Oregon and California has been challenging. Irrigators have increasingly turned to groundwater to make up for surface water shortages because of shifts in allocation toward in-stream flows for Endangered Species Act-listed fishes. The largest increase in groundwater pumping has been in and around the Bureau of Reclamation’s Klamath Irrigation Project, which includes the Tule Lake subbasin in the southern part of the upper Klamath Basin. Previous groundwater flow model simulations indicate that water level declines from pumping may result in decreased flow to agricultural drains in the Tule Lake subbasin. Agricultural drains on the Klamath Project are an important source of water for downstream irrigators and for the Tule Lake and Lower Klamath Lake National Wildlife Refuges. To better assess the impact of increased pumping on drain flow and on the water balance of the groundwater system, flow data from agricultural drains were evaluated to investigate the changes that have taken place in groundwater discharge to drains since pumping volumes increased. Additionally, a fine-grid groundwater model of the Tule Lake subbasin was developed based on the existing regional flow model. The fine-grid model has sufficient vertical and horizontal resolution to simulate vertical head gradients, takes advantage of time-series data from 38 observation wells for model calibration, and allows agricultural drains to be more explicitly represented. Results of the drain flow analysis show that the groundwater discharge to agricultural drains has decreased by approximately 4000 hectare-meters from the 1997-2000 average discharge. Most of this decrease takes place in the northern and southeastern portions of the subbasin.  Results of the groundwater model show that the initial source of water to wells is groundwater storage. By 2006, approximately 56% of the water from wells is sourced from agricultural drains.

Isolating the Poroelastic Response of the Groundwater System in InSAR Data From the Central Valley of California

American Geophysical Union (AGU) | April 28th, 2023