Tule Lake* Subbasin Groundwater Sustainability Plan

Tulelake Subbasin Groundwater Sustainability Agency | June 14th, 2024

*Spelled various as one and two words, Tule Lake and Tulelake, across the GSP submissions. From the GSP: "This ... covers the entire Tule Lake Subbasin, which comprises

*Spelled various as one and two words, Tule Lake and Tulelake, across the GSP submissions. From the GSP: "This ... covers the entire Tule Lake Subbasin, which comprises approximately 64,000 acres of irrigated land near the California-Oregon border. The Subbasin is part of the larger Upper Klamath Basin, which extends into Oregon, and is located within the North Coast Hydrologic Region. The Subbasin is within Modoc County and Siskiyou County, which have been respectively identified as "severely disadvantaged” and “disadvantaged” communities. The majority of land in the Subbasin is also in TID [Tulelake Irrigation District], which covers approximately 84% of the Subbasin. As the most prominent public agency within the Subbasin, TID has been the primary GSA responsible for recent planning activities." Due to length, this document has been divided. Part 1, Part 2

Tule Subbasin Coordination Agreement

University of Massachusetts | January 16th, 2020

Pursuant to 23 Cal. Code Regs. §357.4(a), the GSAs hereby enter into this Coordination Agreement. The Tule Subbasin identified by DWR as No. 5-22-13 of the Tulare Lake H

Pursuant to 23 Cal. Code Regs. §357.4(a), the GSAs hereby enter into this Coordination Agreement. The Tule Subbasin identified by DWR as No. 5-22-13 of the Tulare Lake Hydrologic Region, Figure 1-1, is currently composed of seven GSAs. Each GSA within the Tule Subbasin has previously submitted notice to the Department of its intent to implement and develop its own GSP pursuant to 23 CCR §353.6. As a result, a Coordination Agreement is necessary as multiple GSAs within the Tule Subbasin are developing and implementing independent GSPs. The purpose of this Coordination Agreement is to fulfill all statutory and regulatory requirements related to Intra-basin coordination agreements pursuant to the Sustainable Groundwater Management Act (“SGMA”).

Tule Subbasin Probationary Hearing Final Staff Report

California State Water Resources Control Board (SWRCB) | August 30th, 2024

Board staff identified specific deficiencies in the Tule Subbasin 2022 GSPs and outlined potential corrective actions to address those specific deficiencies. • Chron

Board staff identified specific deficiencies in the Tule Subbasin 2022 GSPs and outlined potential corrective actions to address those specific deficiencies. • Chronic lowering of groundwater levels with insufficient management criteria. • Continued land subsidence (sinking). • Further degradation of groundwater quality. • Depletions of interconnected surface water.

Turlock Subbasin Groundwater Sustainability Plan (Revised)

West and East Turlock Subbasin Groundwater Sustainability Agencies | July 12th, 2024

The Turlock GSAs submitted the first version of the Turlock GSP to the Department of Water Resources (DWR) in January 2022. DWR determined the GSP to be incomplete in J

The Turlock GSAs submitted the first version of the Turlock GSP to the Department of Water Resources (DWR) in January 2022. DWR determined the GSP to be incomplete in January of 2024 (DWR, 2024) and identified two deficiencies. The first of these involves provision of sufficient information (namely, analysis of potential impacts on wells) to support the selection of sustainable management criteria for chronic lowering of groundwater levels. The second involves the provision of sufficient details on the projects and management actions to mitigate overdraft in the Subbasin and to provide a feasible path to achieve sustainability. Corrective actions are incorporated into this revised July 16, 2024 GSP for resubmittal to DWR. This does not represent a GSP update, which is slated for 2027. The revised GSP was adopted by the GSAs on July 11, 2024 pursuant to 23 CCR § 355.2(e)(2)(A).

Twenty-first century hydroclimate: A continually changing baseline, with more frequent extremes

National Academy of Sciences (NAS) | March 14th, 2022

Variability in hydroclimate impacts natural and human systems worldwide. In particular, both decadal variability and extreme precipitation events have substantial effect

Variability in hydroclimate impacts natural and human systems worldwide. In particular, both decadal variability and extreme precipitation events have substantial effects and are anticipated to be strongly influenced by climate change. From a practical perspective, these impacts will be felt relative to the continuously evolving background climate. Removing the underlying forced trend is therefore necessary to assess the relative impacts, but to date, the small size of most climate-model ensembles has made it difficult to do this. Here we use an archive of large ensembles run under a high-emissions scenario to determine how decadal “megadrought” and “megapluvial” events—and shorter-term precipitation extremes—will vary relative to that changing baseline. When the trend is retained, mean state changes dominate: In fact, soil moisture changes are so large in some regions that conditions that would be considered a megadrought or pluvial event today are projected to become average. Time-of-emergence calculations suggest that in some regions including Europe and western North America, this shift may have already taken place and could be imminent elsewhere: Emergence of drought/pluvial conditions occurs over 61% of the global land surface (excluding Antarctica) by 2080. Relative to the changing baseline, megadrought-/megapluvial risk either will not change or is slightly reduced. However, the increased frequency and intensity of both extreme wet and dry precipitation events will likely present adaptation challenges beyond anything currently experienced. In many regions, resilience against future hazards will require adapting to an ever-changing “normal,” characterized by unprecedented aridification/wetting punctuated by more severe extremes.

U.S. Geological Survey Climate Science Plan — Future Research Directions

U.S. Geological Survey (USGS) | September 6th, 2024

Climate is the primary driver of environmental change and is a key consideration in defining science priorities conducted across all mission areas in the U.S. Geological

Climate is the primary driver of environmental change and is a key consideration in defining science priorities conducted across all mission areas in the U.S. Geological Survey (USGS). Recognizing the importance of climate change to its future research agenda, the USGS’s Climate Science Steering Committee requested the development of a Climate Science Plan to identify future research directions. Subject matter experts from across the Bureau formed the USGS Climate Science Plan Writing Team, which convened in September 2022 to identify and outline the major climate science topics of future concern and develop an integrated approach to conducting climate science in support of the USGS and U.S. Department of the Interior missions.

U.S. Global Change Research Program (USGCRP)

Congressional Research Service (CRS) | April 1st, 2025

The U.S. Global Change Research Program (USGCRP) is an interagency program established by Congress through the Global Change Research Act of 1990 (GCRA; P.L. 101-606) to

The U.S. Global Change Research Program (USGCRP) is an interagency program established by Congress through the Global Change Research Act of 1990 (GCRA; P.L. 101-606) to coordinate and integrate federal research on global change. Global change refers to global environmental changes in the Earth’s climate, land productivity, water resources, atmospheric chemistry, and ecological systems that may affect Earth’s capacity to sustain life. USGCRP was established to enhance scientific understanding of global changes and assess their potential impacts, and for the program’s results to be useful for those developing policy responses. As the Trump Administration looks to alter executive branch activities related to climate change, an issue for the 119th Congress may be whether—and if so, how—to alter congressional direction and funding for USGCRP and its activities.

Uncertainty in El Niño-like warming and California precipitation changes linked by the Interdecadal Pacific Oscillation

Nature Portfolio (Springer Nature) | November 10th, 2021

Marked uncertainty in California (CA) precipitation projections challenges their use in adaptation planning in the region already experiencing severe water stress. Under

Marked uncertainty in California (CA) precipitation projections challenges their use in adaptation planning in the region already experiencing severe water stress. Under global warming, a westerly jet extension in the North Pacific analogous to the El Niño-like teleconnection has been suggested as a key mechanism for CA winter precipitation changes. However, this teleconnection has not been reconciled with the well-known El Niño-like warming response or the controversial role of internal variability in the precipitation uncertainty. Here we find that internal variability contributes > 70% and > 50% of uncertainty in the CA precipitation changes and the El Niño-like warming, respectively, based on analysis of 318 climate simulations from several multi-model and large ensembles. The Interdecadal Pacific Oscillation plays a key role in each contribution and in connecting the two via the westerly jet extension. This unifying understanding of the role of internal variability in CA precipitation provides critical guidance for reducing and communicating uncertainty to inform adaptation planning.

Untapped Potential: An Assessment of Municipal and Industrial Water Efficiency Potential in the United States

Pacific Institute | October 28th, 2025

Water is one of our most precious and vital natural resources and is fundamental for human and ecological health and economic prosperity. Yet, water scarcity is a growing

Water is one of our most precious and vital natural resources and is fundamental for human and ecological health and economic prosperity. Yet, water scarcity is a growing risk for communities across the United States, due in part to natural hydrologic variability, population and economic growth, and the intensifying effects of climate change. The good news is that over the past several decades, communities across the United States have improved the efficiency of their water use, enabling growth and economic activity nationwide. Many communities have seen marked reductions in the amount of water used per person. For some, these reductions have been substantial enough that total water demand has peaked and declined even as the population and economy continue to grow. Even as traditional water sources are stressed, the opportunity to reduce demand through water efficiency remains both vast and largely untapped.

Update on an Analysis of a Potential Groundwater Storage and Recovery Program in the Carpinteria Groundwater Basin

Montecito Water District (MWD) | March 11th, 2025