The tidal wetlands of San Francisco Bay provide numerous benefits to the region, including carbon sequestration, flood protection, providing habitat for native and endangered species, protecting shoreline communities and infrastructure from wave impact, improving water quality, and supporting a range of cultural and recreational uses. Our collective investment in conservation and restoration since the early 1990s has reversed the trend of wetland loss in the Bay, and has led to steady progress toward regional restoration goals.

The newly established Wetlands Regional Monitoring Program (WRMP; wrmp.org) is overseeing regular mapping of baylands habitats as part of its regional-scale monitoring aimed at increasing the impact, utility, and application of permit-driven monitoring to inform science-based decision-making. Such mapping is crucial for understanding how tidal wetlands are changing over time and for tracking and informing management actions. The recently released Baylands Habitat Map (BHM) 2020 used cutting-edge automated mapping techniques paired with a standardized habitat classification scheme to map wetlands in the Bay. Using BHM 2020 data and restoration project information from EcoAtlas Project Tracker, the WRMP has calculated a new estimate of tidal wetlands in the Bay: 53,700 acres as of 2020.

This new 2020 estimate shows an increase in tidal wetland extent compared to previous ones. The 2015 Baylands Ecosystem Habitat Goals Update estimated that there were 46,000 acres of tidal wetland as of 2009, and the State of the Estuary Report estimated there were 52,800 acres of tidal wetland as of 2019. Slight differences in mapping and calculation approaches between different reporting methods in the past complicate making direct comparisons among previous tidal wetland extent numbers. The WRMP will provide a standardized mapping approach and regular reporting moving forward, creating more consistent, repeatable and cost-effective tracking of tidal wetland extent.