San Francisco Bay

Irrigation of Twelve Million Acres in the Valley of California

U.S. Geological Survey (USGS) | November 15th, 1920

Irrigation Water Use in the Central Valley of California

California Department of Water Resources (DWR) | January 1st, 1985

Jet stream dynamics, hydroclimate, and fire in California from 1600 CE to present

National Academy of Sciences (NAS) | March 4th, 2019

Moisture delivery in California is largely regulated by the strength and position of the North Pacific jet stream (NPJ), winter high-altitude winds that influence regiona

Moisture delivery in California is largely regulated by the strength and position of the North Pacific jet stream (NPJ), winter high-altitude winds that influence regional hydroclimate and forest fire during the following warm season. We use climate model simulations and paleoclimate data to reconstruct winter NPJ characteristics back to 1571 CE to identify the influence of NPJ behavior on moisture and forest fire extremes in California before and during the more recent period of fire suppression. Maximum zonal NPJ velocity is lower and northward shifted and has a larger latitudinal spread during presuppression dry and high-fire extremes. Conversely, maximum zonal NPJ is higher and southward shifted, with narrower latitudinal spread during wet and low-fire extremes. These NPJ, precipitation, and fire associations hold across pre–20th-century socioecological fire regimes, including Native American burning, postcontact disruption and native population decline, and intensification of forest use during the later 19th century. Precipitation extremes and NPJ behavior remain linked in the 20th and 21st centuries, but fire extremes become uncoupled due to fire suppression after 1900. Simulated future conditions in California include more wet-season moisture as rain (and less as snow), a longer fire season, and higher temperatures, leading to drier fire-season conditions independent of 21st-century precipitation changes. Assuming continuation of current fire management practices, thermodynamic warming is expected to override the dynamical influence of the NPJ on climate–fire relationships controlling fire extremes in California. Recent widespread fires in California in association with wet extremes may be early evidence of this change.

Juvenile Production Estimate (JPE) Calculation and Use/Application of Survival Data from Acoustically-tagged Chinook Salmon Releases Report

Delta Stewardship Council (Delta Council) | February 21st, 2014

Each year, NOAA’s National Marine Fisheries Service (NMFS) estimates the number of juvenile winter-run Chinook salmon expected to enter the Delta. NMFS’ June 4, 2009

Each year, NOAA’s National Marine Fisheries Service (NMFS) estimates the number of juvenile winter-run Chinook salmon expected to enter the Delta. NMFS’ June 4, 2009, biological and conference opinion on the long-term operation of the Central Valley Project and State Water Project provides an incidental take limit on natural juvenile winter-run based on the juvenile production estimate.

Land Reclamation Impacts on Tidal Landscape Evolution

American Geophysical Union (AGU) | August 21st, 2025

Fertile and low-lying coastal landscapes are often densely populated due to food supply (agriculture, aquaculture, and fisheries) and easy navigability (shipping lanes).

Fertile and low-lying coastal landscapes are often densely populated due to food supply (agriculture, aquaculture, and fisheries) and easy navigability (shipping lanes). Much of the low-lying land that is regularly inundated by the sea has been converted to agricultural land or urban environments to meet the need for land. This reclamation of land influences the tidal dynamics of the coastal environment, which in turn modifies its morphology. Through various complex tide-topography interactions identified in this paper, we explore how the location and extent of land reclamation influences tides and bed levels in various tidal environments. We especially point to the key role of sediments herein, introducing feedback mechanisms that lead to large impacts on tidal landscapes, but also long adaptation times. This is especially the case for estuaries due to their confinement and the typically large availability of sediments.

Land Subsidence in Santa Clara Valley, Alameda, San Mateo, and Santa Clara Counties California

U.S. Geological Survey (USGS) | January 31st, 1971

Land Subsidence in the Santa Clara Valley, California, as of 1982

U.S. Geological Survey (USGS) | July 31st, 1988

Land Transitions and Dust in the San Joaquin Valley

Public Policy Institute of California (PPIC) | July 24th, 2022

The Sustainable Groundwater Management Act (SGMA) requires groundwater users to bring their basins into balance over the next two decades. In the San Joaquin Valley, this

The Sustainable Groundwater Management Act (SGMA) requires groundwater users to bring their basins into balance over the next two decades. In the San Joaquin Valley, this will mean taking more than 500,000 acres of agricultural land out of intensive irrigated production. Among other issues, this could potentially lead to air quality impacts if the lands become new sources of dust, especially windblown dust, which can have numerous negative short- and long-term health and environmental impacts. In addition, the changing climate may exacerbate risks as warmer temperatures can dry out soils and increase dust emissions. The overall air quality impact of transitioning agricultural land to new uses is nuanced, but proactive management can help to identify high-risk areas and at-risk communities, and direct effort and funding to the most cost-effective interventions.

LandFlex Grant Program Guidelines

California Department of Water Resources (DWR) | January 14th, 2023

The California Department of Water Resources (DWR) is administering the LandFlex Grant Program (LandFlex) through DWR’s Sustainable Groundwater Management (SGM) Grant P

The California Department of Water Resources (DWR) is administering the LandFlex Grant Program (LandFlex) through DWR’s Sustainable Groundwater Management (SGM) Grant Program. LandFlex (referred to as Ag Drought Relief) will award funds authorized by the California Budget Act of 2021 (Stats. 2021, ch. 44, § 25). This document contains DWR’s Guidelines and scoring criteria (Guidelines) for LandFlex. Climate change means that California needs to plan for a hotter, drier future. Long-term drought, fueled by climate change, has adversely affected the State’s water supplies, which includes groundwater availbility. In response to the Governor’s California’s Water Supply Strategy, Adapting to a Hotter, Drier Future, DWR will launch the LandFlex Program as a new and innovative tool to protect vulnerable drinking water wells. LandFlex will provide incentives to farmers to limit groundwater pumping in areas near communities reliant on vulnerable drinking water wells before they go dry. LandFlex combines traditional short-term fallowing incentives with the elimination of long-term unsustainable groundwater pumping, a unique approach to groundwater resilience. LandFlex is a program that will provide $25 million in block grants to local government agencies to grant to farmers who limit agricultural water use. Local government agencies will work directly with farmers in critically overdrafted (COD) basins (as identified in Bulletin 118) to identify lands that would reduce pumping impacts to nearby drinking water wells. Through financial incentives to farmers, LandFlex will provide multiple community benefits such as drinking water well relief, groundwater overdraft prevention, and climate resilience.

Landscape Patterns and Processes of the McCormack-Williamson Tract and Surrounding Area: A framework for restoring a resilient and functional landscape

San Francisco Estuary Institute (SFEI) | March 25th, 2013

This report uses a reconstruction of the historical (early 19th century) Sacramento-San Joaquin Delta landscape in concert with contemporary data to elucidate restoration

This report uses a reconstruction of the historical (early 19th century) Sacramento-San Joaquin Delta landscape in concert with contemporary data to elucidate restoration opportunities and constraints at the McCormack-Williamson Tract and within the surrounding Delta setting. Historical ecology encourages a landscape-level perspective of restoration through improved understanding of how physical processes created and maintained habitat mosaics in the recent past. This perception of landscapes can be used to evaluate current conditions and develop future restoration scenarios. We used the recently completed study of the historical Delta landscape (Whipple et al. 2012) to explore opportunities for the McCormack-Williamson Tract (MWT), a 1,645 acre (6.6 km2) tract along the Mokelumne River (Figure 1 and Figure 2). This site exemplifies the need to balance contemporary constraints to restoration (including existing infrastructure and flood protection concerns) with the goals of landscape-scale restoration. To explore some of the strategies and opportunities available to advance the landscape-scale restoration in the MWT area, three general concepts emerged: increasing landscape complexity, connectivity, and resilience. To understand how to interpret and improve these attributes, we developed conceptual models that placed the site within the larger landscapes of the historical Delta, relating local habitat features to regional controlling physical gradients. This aided interpretation of the contemporary physical landscape and allowed identification of opportunities and constraints to both short-term and long-term landscape-scale restoration. The historical record reveals features such as floodplain lakes, forests on natural river levees, and tidal channels in the study area. These and other features could be strategically incorporated into a restoration vision, or an “operational landscape unit” for this part of the Delta (Verhoeven et al. 2008). This type of perspective can help focus restoration targets, including the relative proportion and placement of different habitat types and landscape elements within project design constraints, maximizing the site’s ecological potential. The landscape-scale approach also identifies opportunities to improve ecological connectivity and long-term adaptability to sea level rise and other environmental changes. Some of these opportunities may be critical to the ecological function and resilience of the area, but may not be able to be addressed in the immediate MWT project design. Thus, a central component of translating a historical landscape perspective to site-scale design is envisioning an adaptable restoration process that spans short-term restoration actions that are possible within the site’s bounds, while maintaining a longer-term vision of what is needed at the landscape scale.