Lower Tule River Irrigation District Groundwater Sustainability Plan San, Joaquin - Tule Subbasin

Lower Tule River Irrigation District Groundwater Sustainability Agency | July 19th, 2023

This Plan addresses the items identified in the SGMA regulations specific to the Agency, including descriptions of the physical characteristics, the water budget (histor

This Plan addresses the items identified in the SGMA regulations specific to the Agency, including descriptions of the physical characteristics, the water budget (historic and future), specific monitoring features and locations, quantifiable targets and minimum thresholds for depth to groundwater, groundwater storage, groundwater quality, and land subsidence between 2020 and 2040, and those projects and management actions proposed to implement during the 20 year planning horizon to achieve the Sustainability Goal.

Machine learning based downscaling of GRACE-estimated groundwater in Central Valley, California

Science of the Total Environment (Elsevier) | January 9th, 2023

California's Central Valley, one of the most agriculturally productive regions, is also one of the most stressed aquifers in the world due to anthropogenic groundwater ov

California's Central Valley, one of the most agriculturally productive regions, is also one of the most stressed aquifers in the world due to anthropogenic groundwater over-extraction primarily for irrigation. Groundwater depletion is further exacerbated by climate-driven droughts. Gravity Recovery and Climate Experiment (GRACE) satellite gravimetry has demonstrated the feasibility of quantifying global groundwater storage changes at uniform monthly sampling, though at a coarse resolution and is thus impractical for effective water resources management. Here, we employ the Random Forest machine learning algorithm to establish empirical relationships between GRACE-derived groundwater storage and in situ groundwater level variations over the Central Valley during 2002–2016 and achieved spatial downscaling of GRACE-observed groundwater storage changes from a few hundred km to 5 km. Validations of our modeled groundwater level with in situ groundwater level indicate excellent Nash-Sutcliffe Efficiency coefficients ranging from 0.94 to 0.97. In addition, the secular components of modeled groundwater show good agreements with those of vertical displacements observed by GPS, and CryoSat-2 radar altimetry measurements and is perfectly consistent with findings from previous studies. Our estimated groundwater loss is about 30 km3 from 2002 to 2016, which also agrees well with previous studies in Central Valley. We find the maximum groundwater storage loss rates of −5.7 ± 1.2 km3 yr−1 and -9.8 ± 1.7 km3 yr−1 occurred during the extended drought periods of January 2007–December 2009, and October 2011–September 2015, respectively while Central Valley also experienced groundwater recharges during prolonged flood episodes. The 5-km resolution Central Valley-wide groundwater storage trends reveal that groundwater depletion occurs mostly in southern San Joaquin Valley collocated with severe land subsidence due to aquifer compaction from excessive groundwater over withdrawal.

Major carbon-14 anomaly in a regional carbonate aquifer—Possible evidence for megascale channeling, south-central Great Basin

American Geophysical Union (AGU) | December 1st, 1976

The carbon 14 content of groundwater at the center of a 16‐km‐long fault‐controlled spring line at Ash Meadows in south central Nevada is 5 times greater than that

The carbon 14 content of groundwater at the center of a 16‐km‐long fault‐controlled spring line at Ash Meadows in south central Nevada is 5 times greater than that in water from other major springs along the lineament. The difference in carbon 14 stands in marked contrast to the near identity of all springwaters in alkalinity, pH, carbon 13, oxygen 18, deuterium, tritium, and other major and trace ions. Ten possible explanations of this major carbon 14 anomaly are evaluated by using all available chemical and isotopic data from basin‐wide wells and upland springs tapping the regional carbonate aquifer discharging at Ash Meadows. The four most plausible hypotheses require the presence of a major longitudinal heterogeneity in the distal portion of the groundwater basin to explain the anomaly. Flow channeling with an amplitude of at least 11 km is indicated. The simplifying assumption commonly used in simulation of basin‐wide flow through fractured or solution‐riddled aquifers, namely, that the aquifer is ‘homogenous in its heterogeneity,’ is not applicable to the dense fractured Paleozoic carbonate rocks comprising the Nevada aquifer; heterogeneities in this aquifer do not cancel each other areally.

Major ground-water flow systems in the Great Basin region of Nevada, Utah, and adjacent state

U.S. Geological Survey (USGS) | July 1st, 1988

Majority of global river flow sustained by groundwater

Nature Portfolio (Springer Nature) | July 19th, 2024

Groundwater-sustained baseflow is a vital source of river flow, especially during dry seasons. The proportion of river flow sustained by baseflow—the baseflow index—i

Groundwater-sustained baseflow is a vital source of river flow, especially during dry seasons. The proportion of river flow sustained by baseflow—the baseflow index—is essential for assessing fluvial nutrient cycling and contaminant transport. However, the global baseflow index remains highly uncertain, with current Earth system model simulations ranging from 12% to 94%. Here we estimate the global baseflow index to be 59% ± 7% based on an emergent constraint approach, which integrates 50 Earth system models with baseflow indices derived from streamflow observations in 15,567 basins. Our observational constraint indicates that at least 21% ± 3% of precipitation recharges groundwater, which is approximately double the figure reported in the Sixth Assessment Report of the United Nations Intergovernmental Panel on Climate Change. Thus, our research suggests a more active role of groundwater in the global water cycle than most Earth system models currently simulate. We present evidence that the considerable disagreement in simulated baseflow stems from unrealistic and varied model representations of infiltration, aquifer structure and groundwater dynamics. These processes should be prioritized so that models can capture active groundwater–river connections.

Maladaptation to drought: a case report from California, USA

Sustainability Science (Springer) | October 15th, 2015

The interactions between natural water availability and societal water demand and management are complex. In response to gaps in empirical research of the adaptive capaci

The interactions between natural water availability and societal water demand and management are complex. In response to gaps in empirical research of the adaptive capacity of social and environmental systems to climate stresses, we provide an assessment of responses to water scarcity during a multi-year drought in California. In particular, we use Barnett and O’Neill’s (Global Environ Change 20:211–213, 2010) criteria for maladaptation to examine responses in the agricultural and energy sectors to a multi-year (2007–2009) California drought. We conclude that despite evidence in both sectors of resiliency to the impacts of the drought, some of the coping strategies adopted increased the vulnerability of other systems. These other systems include California’s aquatic ecosystems and social groups that rely on those ecosystems for their health or employment; future generations whose resources were drawn down in the near-term, where otherwise those resources would have been available at a later time; and current and future generations who were, or will be, exposed to the effects of increased greenhouse gas emissions. This case study demonstrates that California’s current strategies for dealing with long or severe droughts are less successful than previously thought when short- and long-term impacts are evaluated together. This finding is particularly relevant given projections of more frequent and severe water shortages in the future due to climate change. This study recommends a shift from crisis-driven responses to the development and enactment of long-term mitigation measures that are anticipatory and focus on comprehensive risk reduction.

Managed Aquifer Recharge and the U.S. Army Corps of Engineers: Water Security through Resilience

U.S. Army Corps of Engineers (USACE) | May 14th, 2020

Managed Aquifer Recharge in California: Four Examples of Managed Groundwater Replenishment Across the State

American Geosciences Institute (AGI) | September 29th, 2017

In California, surface water from rainfall, snowmelt, and distant rivers rarely meets the state’s urban and agricultural water needs. Groundwater is an essentia

In California, surface water from rainfall, snowmelt, and distant rivers rarely meets the state’s urban and agricultural water needs. Groundwater is an essential water source, providing 35% of the fresh water used in California. However, when groundwater is used more rapidly than it is naturally replenished, groundwater management becomes necessary. One of the tools used by groundwater managers is managed aquifer recharge (MAR). Aquifers, the porous rocks and sediments that hold and transmit groundwater, are naturally replenished by surface water that seeps into the ground. MAR enhances the recharge rate by creating artificial streams and ponds where water trickles into the ground, or by using wells to directly inject water underground. MAR can also be used to improve groundwater quality and prevent some of the negative consequences of groundwater depletion, like ground sinking (subsidence) or the intrusion of salty groundwater from the oceans into coastal freshwater aquifers. Because of its arid climate and large population, California is home to some of the oldest and largest MAR projects in the United States. This case study highlights four of these projects, covering almost a century of MAR and water security in California.

Managed winter flooding of alfalfa recharges groundwater with minimal crop damage

California Agriculture (UCANR) | January 16th, 2018

It is well known that California experiences dramatic swings in precipitation that are difficult to predict and challenging to agriculture. In times of drought, groundwat

It is well known that California experiences dramatic swings in precipitation that are difficult to predict and challenging to agriculture. In times of drought, groundwater serves as a crucial savings account that is heavily relied upon. However, few tools exist to proactively refill this crucial reserve in wet years. We explored the idea of intentional winter flooding of agricultural land to promote on-farm recharge of the underlying groundwater. Field experiments were conducted on two established alfalfa stands to determine the feasibility of groundwater recharge and test realistic water application amounts and timings and potential crop damage. We studied soils with relatively high percolation rates and found that most of the applied water percolated to the groundwater table, resulting in short-lived saturated conditions in the root zone and minimal yield loss. While caution is appropriate to prevent crop injury, winter recharge in alfalfa fields with highly permeable soils appears to be a viable practice.

Managing Surface Water-Groundwater to Restore Fall Flows in the Cosumnes River

American Society of Civil Engineers (ASCE) | June 15th, 2004

Declining fall flows are limiting the ability of the Cosumnes River to support large fall runs of Chinook salmon. Management scenarios linking surface water and g

Declining fall flows are limiting the ability of the Cosumnes River to support large fall runs of Chinook salmon. Management scenarios linking surface water and groundwater alternatives to provide sufficient fall flows are examined using groundwater flow and channel routing models. Results show that groundwater overdraft in the basin has converted the river to a predominantly losing stream, practically eliminating base flows. Management alternatives to increase net recharge for example, pumping reductions were examined along with surface water augmentation options. Using a minimum depth standard for fish passage, average surface water flow deficits were computed for the migration period of Chinook salmon. Groundwater deficits were evaluated by comparing simulated current groundwater conditions with conditions under various scenarios. Increases in net recharge on the order of 200 to 300 million m3/year would be required to reconnect the regional aquifer with the channel and in turn reestablish perennial base flows. Options that combine surface water augmentation with groundwater management are most likely to ensure sufficient river flows in the short term and to support long-term restoration of regional groundwater levels.