San Francisco Bay

The Impact of Sea Level Rise on San Francisco Bay

California Energy Commission (CEC) | July 1st, 2014

Over the past century, sea level has risen nearly eight inches along the California coast, and general circulation model scenarios suggest very substantial increases in s

Over the past century, sea level has risen nearly eight inches along the California coast, and general circulation model scenarios suggest very substantial increases in sea level as a significant impact of climate change over the coming century. This study includes a detailed analysis of the current population, infrastructure, and property along the San Francisco Bay that are at risk from projected sea level rise if no actions are taken to protect the coast. The sea level rise scenario was developed by the State of California from medium to high greenhouse gas emissions scenarios from the Intergovernmental Panel on Climate Change but does not reflect the worst?case sea level rise that could occur. If development continues in the areas at risk, all of these estimates will rise. No matter what policies are implemented in the future, sea level rise will inevitably change the character of the San Francisco Bay. We estimate that a 1.0 meter (m) sea level rise will put 220,000 people at risk of a 100?year flood event, given today’s population. With a 1.4 m increase in sea levels, the number of people at risk of a 100?year flood event would rise to 270,000. Among those affected are large numbers of low?income people and communities of color, which are especially vulnerable. Critical infrastructure, such as roads, hospitals, schools, emergency facilities, wastewater treatment plants, power plants, and more will be at increased risk of inundation, as will vast areas of wetlands and other natural ecosystems. In addition, the cost of replacing property at risk of coastal flooding with a 1.0 m rise in sea levels is $49 billion (in year 2000 dollars). A rise of 1.4 m would increase the replacement cost to $62 billion (in year 2000 dollars). Continued development in vulnerable areas will put additional areas at risk and raise protection costs. A number of structural and non?structural policies and actions, which are described qualitatively, could be implemented to reduce these risks.

The impacts of climate change on coastal groundwater

Nature Portfolio (Springer Nature) | January 11th, 2024

Coastal groundwater (CGW) is a critical water resource for many communities and can be a key part of coastal ecosystems. Owing to its location, CGW faces both terrestrial

Coastal groundwater (CGW) is a critical water resource for many communities and can be a key part of coastal ecosystems. Owing to its location, CGW faces both terrestrial and marine effects of climate change while simultaneously being impacted by anthropogenic activities. In this Review, we discuss the expected impacts of climate change on CGW and CGW-dependent ecosystems. Sea-level rise, coastal flooding increases and precipitation and aridity changes will drive alterations in the amount, chemistry and fluxes of CGW. Impacts could also arise from changes in storm and cyclone activity, land and ocean temperature rises, cryosphere melt, ocean chemistry and coastal erosion, but the overall effect is understudied. Human-induced stressors, such as groundwater extraction, will interact with climate change impacts to alter CGW at different temporal and spatial scales. CGW-associated ecosystems are expected to respond to changes in an ecosystem and site-specific manner — for example, some coastal temperate and tropical ecosystems might be more impacted by seawater intrusion owing to sea-level rise and coastal flooding, whereas others, such as coastal polar ecosystems, could be more affected by increases in cryosphere melt. A comprehensive and global CGW observatory programme is needed to better understand baseline CGW conditions, track change and support resource management.

The Influence of Zooplankton Availability on Delta Smelt Condition and Foraging Across Habitat Contexts

Publisher not available | December 19th, 2025

Strategies for endangered species conservation may have different outcomes depending on the habitat context in which they are implemented. Understanding these context-dep

Strategies for endangered species conservation may have different outcomes depending on the habitat context in which they are implemented. Understanding these context-dependent effects can help optimize and target management efforts. In this analysis, we investigate how environmental and food-web conditions interactively affect condition and foraging of Delta Smelt (Hypomesus transpacificus), an endangered fish endemic to the San Francisco Estuary (the estuary). Food limitation, in terms of pelagic zooplankton availability, is considered a main factor that contributes to the decline in Delta Smelt abundance. Our overarching objective was to examine whether the effect of zooplankton on Delta Smelt depended on habitat context. Specifically, we hypothesized that zooplankton would less positively effect Delta Smelt condition—as measured by hepatosomatic index (HSI)—and foraging success in areas with nearby tidal wetlands, because these adjacent habitats may provide access to prey items from the epibenthos and fringing vegetation. In contrast, in regions with limited proximity to wetlands, we hypothesized that Delta Smelt would rely more on pelagic prey, which would manifest as a more positive effect of zooplankton on body condition and foraging success for Delta Smelt. Using models that accounted for habitat in multiple ways, we found little evidence that zooplankton and habitat interactively influenced Delta Smelt condition or gut fullness. Rather, the influence of zooplankton on HSI and gut fullness was generally positive across habitat contexts. Given the well-documented food limitation in the estuary, promoting the availability of pelagic zooplankton is a rational, albeit complex, management aim. Furthermore, our results suggest that efforts to increase zooplankton would broadly benefit Delta Smelt across a wide range of habitat contexts.

The Magnitude of California's Water Challenges

UnIversity of California, Davis (UC Davis) | June 4th, 2024

California will see increasing water scarcity from climate change, the end of overdrafting groundwater and the Colorado River’s massive reservoirs, increased water dedi

California will see increasing water scarcity from climate change, the end of overdrafting groundwater and the Colorado River’s massive reservoirs, increased water dedications for environmental flows, and other factors, such as salination of aquifers and land subsidence reducing canal capacities. Total reduction in average water availability in the coming decades will likely range from 4.6 to 9 million acre-feet per year. For context, this is equivalent to the water use of 1 – 2.8 million acres of irrigated agriculture or most urban water use in California. Perhaps 20-30% of this loss will likely be addressed by ongoing water conservation and supply improvements, being planned and implemented, leaving a 3 – 7.2 million acre-feet/year likely net average difference between statewide water demands and availability.

The Metropolitan Water District of Southern California Annual Report for the Fiscal Year July 1, 2018 to June 30, 2019

Metropolitan Water District of Southern California (MWD) | December 1st, 2019

The NOAA NCEI marine microplastics database

Nature Portfolio (Springer Nature) | October 20th, 2023

Microplastics (<5 mm) pollution is a growing problem affecting coastal communities, marine ecosystems, aquatic life, and human health. The widespread occurrence of m

Microplastics (<5 mm) pollution is a growing problem affecting coastal communities, marine ecosystems, aquatic life, and human health. The widespread occurrence of marine microplastics, and the need to curb its threats, require expansive, and continuous monitoring. While microplastic research has increased in recent years and generated significant volumes of data, there is a lack of a robust, open access, and long-term aggregation of this data. The National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information (NCEI) now provides a global open access to marine microplastics data on an easily discoverable and accessible GIS web map and data portal. The objective of this data portal is to develop a repository where microplastics data are aggregated, archived, and served in a user friendly, consistent, and reliable manner. This work contributes to NCEI’s efforts towards data standardization, integration, harmonization, and interoperability among national and international collaborators for monitoring global marine microplastics. This paper describes the NOAA NCEI global marine microplastics database, its creation, quality control procedures, and future directions.

The Once and Future Delta: Mending the broken heart of California

Bay Nature | April 1st, 2010

On March 30, 1772, Spanish explorer Pedro Pages was traveling east along the south shore of Suisun Bay, looking for a land route around the seemingly endless chain of b

On March 30, 1772, Spanish explorer Pedro Pages was traveling east along the south shore of Suisun Bay, looking for a land route around the seemingly endless chain of bays extending inland from the Golden Gate. Mounting to Willow Pass, the rise of land between present-day Concord and Pittsburg, he found himself staring at a new obstacle: an enormous expanse of marshland, threaded with bright channels. He had "discovered" the Sacramento-San Joaquin River Delta.

The Pacific Decadal Oscillation modulated marine heatwaves in the Northeast Pacific during past decades

Nature Portfolio (Springer Nature) | June 19th, 2023

The potential of collaborative solutions to improve management of California (United States) wildlands

Restoration Ecology, Society for Ecological Restoration (SER) | November 13th, 2024

The Pulse of the Bay 2019: Pollutant Pathways

San Francisco Estuary Institute (SFEI) | September 26th, 2019

Pollutants make their way to San Francisco Bay from near and far. Some pollutants come from the other side of the world, such as the mercury that is emitted into the atmo

Pollutants make their way to San Francisco Bay from near and far. Some pollutants come from the other side of the world, such as the mercury that is emitted into the atmosphere by coal-fired power plants in Asia, transported across the Pacific Ocean by the wind, and deposited on the surface of the Bay and in the Bay watershed. Some pollutants come from the far corners of the Bay’s watershed, which encompasses 40% of the land surface of California. Mercury used in historic gold mining regions in the Sierra Nevada is still flowing downstream into Central Valley rivers, through the Delta, and into the Bay.  Most pollutants, however, originate from activities closer to home in the small, local watersheds that surround the Bay. Rain that falls onto yards, roofs, parking lots, streets, farms, pastures, and other surfaces in the watersheds picks up pollutants and carries them to the Bay through an intricate network of thousands of miles of storm drain pipes, culverts, and creeks. Most of this stormwater flows to the Bay without any form of pollutant removal.  Another parallel and intricate network of thousands of miles of pipes carries wastewater from homes, business, and industries through sewage collection systems to municipal wastewater treatment plants. These treatment plants are highly effective at removing most pollutants from the wastewater stream, but some are not effectively treated and pass through to the Bay.  Some industrial operations, such as the Bay Area’s petroleum refineries, are large enough to warrant having their own wastewater treatment facilities that remove pollutants so the effluent can be safely discharged into the Bay, reused in plant operations, or applied to land.  Disposal of dredged material at designated sites within the Bay is another activity that introduces pollutants to specific areas in the Bay, but in this case the pollutants are simply transferred from one part of the Bay to another. Much of the pollutant mass in dredged material is also removed from the Bay via disposal in the ocean or beneficial reuse in wetlands and upland sites. This edition of the Pulse of the Bay features articles on the four major pollutant pathways that are the primary focus of Bay water quality managers: municipal wastewater, industrial wastewater, stormwater, and dredging and dredged material disposal.