Sustained groundwater loss in California's Central Valley exacerbated by intense drought periods

American Geophysical Union (AGU) | July 4th, 2018

The accelerated rate of decline in groundwater levels across California’s Central Valley resultsfrom overdrafting and low rates of natural recharge and is exacerbated b

The accelerated rate of decline in groundwater levels across California’s Central Valley resultsfrom overdrafting and low rates of natural recharge and is exacerbated by droughts. The lack of observations with an adequate spatiotemporal resolution to constrain the evolution of groundwater resources poses severe challenges to water management efforts. Here we present SAR interferometric measurements of high-resolution vertical land motion across the valley, revealing multiscale patterns of aquifer hydrogeological properties and groundwater storage change. Investigating the depletion and degradation of the aquifer-system during 2007–2010, when the entire valley experienced a severe drought, we find that ~2% of total aquifer-system storage was permanently lost, owing to irreversible compaction of the system. Over this period, the seasonal groundwater storage change amplitude of10.11 ± 2.5 km3modulates a long-term groundwater storage decline of 21.32 ± 7.2 km3. Estimates for subbasins show more complex patterns, most likely associated with local hydrogeology, recharge, demand, and underground flow. Presented measurements of aquifer-system compaction provide a more complete understanding of groundwater dynamics and can potentially be used to improve water security.

Sustaining California Agriculture in an Uncertain Future

Pacific Institute | July 22nd, 2009

The report Sustaining California Agriculture in an Uncertain Future shows that California agriculture can flourish despite diminishing water supply and future uncertainty

The report Sustaining California Agriculture in an Uncertain Future shows that California agriculture can flourish despite diminishing water supply and future uncertainty from climate change, but it will require great strides in increasing the water efficiency of the agricultural sector. Many farmers and irrigation districts have already been making water-use efficiency improvements. Yet the analysis estimates that potential water savings of 4.5 – 6 million acre-feet each year can be achieved by expanding the use of efficient irrigation technologies and management practices.

Sutter Bypass East Levee Project Initial Study/Proposed Mitigated Negative Declaration

California Department of Water Resources (DWR) | July 10th, 2025

Sutter County Groundwater Management Plan

Sutter County | March 19th, 2012

Sutter County intends this GMP to be relevant for the entire County. Sutter County overlies the south central part of the Sacramento Valley Groundwater Basin, and specif

Sutter County intends this GMP to be relevant for the entire County. Sutter County overlies the south central part of the Sacramento Valley Groundwater Basin, and specifically the Sutter Subbasin and portions of the East Butte and North American Subbasins. The majority of the County is serviced by water and irrigation districts, reclamation districts, cities, and public utility districts, which have the authority to manage groundwater in their service areas. Unless those entities decline to manage groundwater on their own, and instead enter into agreements with the County, this GMP does not formally apply to those areas. If those entities choose not to adopt their own GMPs, they have the option of taking formal action to adopt the Sutter County GMP for their areas. By doing so, they will fulfill the requirements of the groundwater management provisions of the California Water Code.

Sutter Subbasin Groundwater Sustainability Plan

Sutter County | January 28th, 2022

With a 20-year implementation period and a 50-year planning horizon, the Sutter Subbasin GSP is considered to be a “living” document. The Sutter Subbasin Groundwater

With a 20-year implementation period and a 50-year planning horizon, the Sutter Subbasin GSP is considered to be a “living” document. The Sutter Subbasin Groundwater Sustainability Agencies (GSAs) will implement this GSP using adaptive management strategies to respond to challenges related to groundwater sustainability, including monitoring of conditions in the Subbasin according to a prescribed schedule and implementing projects and management actions (PMAs). Conditions will be evaluated on an annual basis (or more frequently, as warranted) utilizing monitoring data collected as part of this GSP, as well as other publicly available sources, and PMAs will be added or revised in the GSP annual reports. During five-year GSP evaluations, the GSP will also be reviewed and revised, as needed, as more is known about the effects of current and future conditions. Due to size, this file has been divided into three parts. Part 1, Part 2, Part 3

Sycamore Alluvial Woodland Habitat Mapping and Regeneration Study

San Francisco Estuary Institute (SFEI) | February 1st, 2017

This study investigates the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodland (SAW), representing managed and nat

This study investigates the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodland (SAW), representing managed and natural settings. Using an array of ecological and geomorphic field analyses, we discuss site characteristics favorable to SAW health and regeneration, make recommendations for restoration and management, and identify next steps. Findings from this study will contribute to the acquisition, restoration, and improved management of SAW as part of the Santa Clara Valley Habitat Plan (VHP). 

Sycamore Alluvial Woodland Planting Guide

San Francisco Estuary Institute (SFEI) | August 1st, 2018

This memo builds on recent field-based studies which examined the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodla

This memo builds on recent field-based studies which examined the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodland (SAW) in Santa Clara County. Given that the acquisition, restoration, and improved management of SAW is mandated as part of the Santa Clara Valley Habitat Plan (VHP), it is increasingly critical to understand how, when, and where sycamores establish, which is critical for successful restoration design and planting success. This memo is meant to summarize recent studies on habitat requirements of the SAW habitat type, and present a planting plan and monitoring framework for restoring SAW habitat at two sites in Santa Clara County. As the science and restoration of SAW is an ongoing topic of interest, we also suggest possible subsequent studies needed to further sycamore restoration goals. 

Sycamore Alluvial Woodland: Habitat Mapping and Regeneration Study

San Francisco Estuary Institute (SFEI) | February 1st, 2017

This study investigates the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodland (SAW), representing managed and nat

This study investigates the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodland (SAW), representing managed and natural settings. Using an array of ecological and geomorphic field analyses, we discuss site characteristics favorable to SAW health and regeneration, make recommendations for restoration and management, and identify next steps. Findings from this study will contribute to the acquisition, restoration, and improved management of SAW as part of the Santa Clara Valley Habitat Plan (VHP). 

Synergies between climate anomalies and hydrological modifications facilitate estuarine biotic invasions

Ecology Letters (Wiley) | June 6th, 2011

Environmental perturbation, climate change and international commerce are important drivers for biological invasions. Climate anomalies can further increase levels of hab

Environmental perturbation, climate change and international commerce are important drivers for biological invasions. Climate anomalies can further increase levels of habitat disturbance and act synergistically to elevate invasion risk. Herein, we use a historical data set from the upper San Francisco Estuary to provide the first empirical evidence for facilitation of invasions by climate extremes. Invasive zooplankton species did not become established in this estuary until the 1970s when increasing propagule pressure from Asia coincided with extended drought periods. Hydrological management exacerbated the effects of post‐1960 droughts and reduced freshwater inflow even further, increasing drought severity and allowing unusually extreme salinity intrusions. Native zooplankton experienced unprecedented conditions of high salinity and intensified benthic grazing, and life history attributes of invasive zooplankton were advantageous enough during droughts to outcompete native species and colonise the system. Extreme climatic events can therefore act synergistically with environmental perturbation to facilitate the establishment of invasive species.

Synergistic Effect of El Niño and Negative Phase of North Atlantic Oscillation on Winter Precipitation in the Southeastern United States

American Meteorological Society (AMS) | February 20th, 2023

This study reveals that the significant increase of winter precipitation over the southeastern United States (SEUS) is associated with El Niño and the negative phase of

This study reveals that the significant increase of winter precipitation over the southeastern United States (SEUS) is associated with El Niño and the negative phase of North Atlantic Oscillation (NAO−). Diagnosis of large-scale dynamics shows that El Niño and NAO− have a synergistic effect on the enhancement of transient eddies and stationary waves in the eastern Pacific, the southern United States, and the North Atlantic. These enhanced transient eddies are associated with subtropical jet stream acceleration and maintenance of subtropical low from the eastern Pacific to the Atlantic, influencing stronger stationary waves propagation from the tropical Pacific to the SEUS and North Atlantic, and from the northwestern Atlantic to the SEUS and Pacific. This favors a positive phase of the meridional dipole in geopotential height anomalies between the tropics and subtropics in the Western Hemisphere (WTSD) during the co-occurrence of El Niño and NAO−. The strong positive WTSD-like pattern, accompanied by a zonally extended and southerly shifted subtropical westerly jet, induces a northward-tilted secondary circulation with ascending motion over the SEUS and Gulf of Mexico. Simultaneously, an intensified trough over the SEUS promotes moisture and warm advection from the subtropical and tropical Pacific converging with cold advection from the northwestern North Atlantic in the adjacent Gulf of Mexico, which is beneficial for front and cyclone generation, and induces precipitation in the SEUS. This study suggests that the synergistic effects of El Niño and NAO− help to understand the variability of winter SEUS precipitation.