Sediment for Survival: A Strategy for the Resilience of Bay Wetlands in the Lower San Francisco Estuary. SFEI Contribution No. 1015. San Francisco Estuary Institute: Richmond, CA.2021.
The resilience of San Francisco Bay shore habitats, such as tidal marshes and mudflats, is essential to all who live in the Bay Area. Tidal marshes and tidal flats (also known as mudflats) are key components of the shore habitats, collectively called baylands, which protect billions of dollars of bay-front housing and infrastructure (including neighborhoods, business parks, highways, sewage treatment plants, and landfills). They purify the Bay’s water, support endangered wildlife, nurture fisheries, and provide people access to nature within the urban environment. Bay Area residents showed their commitment to restoring these critical habitats when they voted for a property tax to pay for large-scale tidal marsh restoration. However, climate change poses a great threat, because there may not be enough natural sediment supply for tidal marshes and mudflats to gain elevation fast enough to keep pace with sea-level rise.
This report analyses current data and climate projections to determine how much natural sediment may be available for tidal marshes and mudflats and how much supplemental sediment may be needed under different future scenarios. These sediment supply and demand estimates are combined with scientific knowledge of natural physical and biological processes to offer a strategy for sediment delivery that will allow these wetlands to survive a changing climate and provide benefits to people and nature for many decades to come. The approach developed in this report may also be useful beyond San Francisco Bay because shoreline protection, flood risk-management, and looming sediment deficits are common issues facing coastal communities around the world.
Related Projects, News, and Events:
SediMatch Web Tool (Project)
SediMatch is a web tool for matching restoration projects that need sediment with navigational and flood protection dredging projects and other "sediment suppliers" throughout the region to meet current and future sediment supply needs.
Healthy Watersheds Resilient Baylands (Project)
Through the EPA-funded Healthy Watersheds Resilient Baylands project, SFEI and sixteen partner organizations are developing multi-benefit tools to enhance climate change resilience in San Francisco Bay. Healthy Watersheds Resilient Baylands has two major components: Multi-benefit Urban Greening and Tidal Wetlands Restoration. Through both components, we have developed strategies that inform policy, planning, and design of innovative implementation projects.
Sediment for Survival (Project)
The tidal marshes and tidal flats along the San Francisco Bay shoreline depend on sediment delivered by the tides. Healthy sediment supplies are essential for maintaining resilient marshes and tidal flats that can persist into the future and build up as sea level continues to rise. Currently, the sediment supply in the Bay is adequate to meet the sediment needed by tidal marshes and tidal flats. However, as sea level rise accelerates in the coming decades, the sediment needed for these habitats to survive will increase considerably.
Sediment for Survival report released (News)
SFEI worked with local, state, and federal science experts to develop the new Sediment for Survival report. The report provides a regional sediment strategy aimed at examining the future of sediment in the Bay and informing sediment management for the resilience of tidal marshes and tidal flats to climate change.