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 Draft Staff Report

California State Water Resources Control Board (SWRCB) | March 1st, 2024

The State Water Board recognizes that local public agencies in the Tule Subbasin significant efforts since the passage of SGMA to form groundwater sustainability agencies

The State Water Board recognizes that local public agencies in the Tule Subbasin significant efforts since the passage of SGMA to form groundwater sustainability agencies (GSAs) and then develop detailed technical and other information supporting the adoption and implementation of six groundwater sustainability plans (GSPs) for the subbasin. Despite those efforts, in January of 2022, DWR reviewed GSPs to determine if the GSPs met SGMA’s requirements and found it to be incomplete. Following revisions made by the GSAs in the subbasin, DWR reevaluated the GSPs in March of 2023, determined the GSPs to be inadequate, and referred the subbasin to the State Water Board, as required by SGMA. Consistent with SGMA, the State Water Board may now consider whether to designate the Tule Subbasin as a “probationary basin,” a term that is used in SGMA to describe a basin in the first stage of state intervention.

Twenty-First Century Levee Overtopping Projections from InSAR-derived subsidence rates in the Sacramento-San Joaquin Delta: 2006–2010

California Energy Commission (CEC) | July 31st, 2012

To provide an updated synoptic assessment of vertical land motion rates in the Sacramento-San Joaquin Delta, the research team performed synthetic aperture radar interfer

To provide an updated synoptic assessment of vertical land motion rates in the Sacramento-San Joaquin Delta, the research team performed synthetic aperture radar interferometry (InSAR) on 35 radar scenes from the Envisat platform acquired from 2006–2010. The study used contemporaneously collected continuous global positioning system data to tie the InSAR results to an absolute reference frame. In accord with the researchers’ previous study from 1995–2000 (VLM00), the new results (VLM10) demonstrate general subsidence of the Delta with respect to its margins. The average rates of ~1-2 millimeters per year (mm/yr) are slightly lower than the ~3-5mm/yr rates from 1995–2000. An unexpected finding is the uplift associated with Roberts Island, in the Delta’s southeastern sector.  The time- and space-varying differences between the two solutions (VLM00 and VLM10) highlights the need to develop a physical model for the Delta. The study used the updated ground-motion rate map and the most current twenty-first century sea-level rise predictions to project when Delta levees will subside below high-water design thresholds. The study showed that the time period between 2050–2075 is a critical time period, when levees will start to fall below design thresholds, and by 2100 most Delta levees will probably do so.

Uplift and seismicity driven by groundwater depletion in central California

Nature Portfolio (Springer Nature) | May 14th, 2014

Groundwater use in California’s San Joaquin Valley exceeds replenishment of the aquifer, leading to substantial diminution of this resource and rapid subsidence of the

Groundwater use in California’s San Joaquin Valley exceeds replenishment of the aquifer, leading to substantial diminution of this resource and rapid subsidence of the valley floor. The volume of groundwater lost over the past century and a half also represents a substantial reduction in mass and a large-scale unburdening of the lithosphere, with significant but unexplored potential impacts on crustal deformation and seismicity. Here we use vertical global positioning system measurements to show that a broad zone of rock uplift of up to 1–3 mm per year surrounds the southern San Joaquin Valley. The observed uplift matches well with predicted flexure from a simple elastic model of current rates of water-storage loss, most of which is caused by groundwater depletion. The height of the adjacent central Coast Ranges and the Sierra Nevada is strongly seasonal and peaks during the dry late summer and autumn, out of phase with uplift of the valley floor during wetter months. Our results suggest that long-term and late-summer flexural uplift of the Coast Ranges reduce the effective normal stress resolved on the San Andreas Fault. This process brings the fault closer to failure, thereby providing a viable mechanism for observed seasonality in microseismicity at Parkfield and potentially affecting long-term seismicity rates for fault systems adjacent to the valley. We also infer that the observed contemporary uplift of the southern Sierra Nevada previously attributed to tectonic or mantle-derived forces is partly a consequence of human-caused groundwater depletion.

Using Sentinel‐1 and GRACE satellite data to monitor the hydrological variations within the Tulare Basin, California

Nature Portfolio (Springer Nature) | March 9th, 2022

Subsidence induced by groundwater depletion is a grave problem in many regions around the world, leading to a permanent loss of groundwater storage within an aquifer and

Subsidence induced by groundwater depletion is a grave problem in many regions around the world, leading to a permanent loss of groundwater storage within an aquifer and even producing structural damage at the Earth’s surface. California’s Tulare Basin is no exception, experiencing about a meter of subsidence between 2015 and 2020. However, understanding the relationship between changes in groundwater volumes and ground deformation has proven difficult. We employ surface displacement measurements from Interferometric Synthetic Aperture Radar (InSAR) and gravimetric estimates of terrestrial water storage from the Gravity Recovery and Climate Experiment (GRACE) satellite pair to characterize the hydrological dynamics within the Tulare basin. The removal of the long-term aquifer compaction from the InSAR time series reveals coherent short-term variations that correlate with hydrological features. For example, in the winter of 2018–2019 uplift is observed at the confluence of several rivers and streams that drain into the southeastern edge of the basin. These observations, combined with estimates of mass changes obtained from the orbiting GRACE satellites, form the basis for imaging the monthly spatial variations in water volumes. This approach facilitates the quick and effective synthesis of InSAR and gravimetric datasets and will aid efforts to improve our understanding and management of groundwater resources around the world.

Water availability and land subsidence in the Central Valley, California, USA

Hydrogeology Journal (Springer) | November 17th, 2015

The Central Valley in California (USA) covers about 52,000 km2 and is one of the most productive agricultural regions in the world. This agriculture relies heavily on sur

The Central Valley in California (USA) covers about 52,000 km2 and is one of the most productive agricultural regions in the world. This agriculture relies heavily on surface-water diversions and groundwater pumpage to meet irrigation water demand. Because the valley is semi-arid and surface-water availability varies substantially, agriculture relies heavily on local groundwater. In the southern two thirds of the valley, the San Joaquin Valley, historic and recent groundwater pumpage has caused significant and extensive drawdowns, aquifer-system compaction and subsidence. During recent drought periods (2007–2009 and 2012-present), groundwater pumping has increased owing to a combination of decreased surface-water availability and land-use changes. Declining groundwater levels, approaching or surpassing historical low levels, have caused accelerated and renewed compaction and subsidence that likely is mostly permanent. The subsidence has caused operational, maintenance, and construction-design problems for water-delivery and flood control canals in the San Joaquin Valley. Planning for the effects of continued subsidence in the area is important for water agencies. As land use, managed aquifer recharge, and surface-water availability continue to vary, long-term groundwater-level and subsidence monitoring and modelling are critical to understanding the dynamics of historical and continued groundwater use resulting in additional water-level and groundwater storage declines, and associated subsidence. Modeling tools such as the Central Valley Hydrologic Model can be used in the evaluation of management strategies to mitigate adverse impacts due to subsidence while also optimizing water availability. This knowledge will be critical for successful implementation of recent legislation aimed toward sustainable groundwater use. *Erratum: Water availability and land subsidence in the Central Valley, California, USA, Faunt, C.C., Sneed, M., Traum, J. et al. Hydrogeol J (2017) 25: 2215

Water availability and subsidence in California’s Central Valley

University of California, Davis (UC Davis) | September 5th, 2015

California’s Central Valley covers about 52,000 square kilometers (km2) and is one of the most productive agricultural regions in the world. More than 250 different c

California’s Central Valley covers about 52,000 square kilometers (km2) and is one of the most productive agricultural regions in the world. More than 250 different crops are grown in the broad alluvial filled structural trough, with an estimated value exceeding $20 billion per year (Faunt 2009) (Figure 1). Central Valley agriculture depends on state and federal water systems that divert surface water, predominantly originating from Sierra Nevada snowmelt, to agricultural fields. Because the valley is semi-arid and the availability of surface water varies substantially from year to year, season to season, and from north to south, agriculture, as it grew, developed a reliance on groundwater for irrigation.

Westside Subbasin Groundwater Sustainability Plan

Westlands Water District | January 23rd, 2020

Widespread aquifer depressurization after a century of intensive groundwater use in USA

American Association for the Advancement of Science (AAAS) | September 15th, 2023