San Francisco Bay Eelgrass Impact Assessment Tool

This web-based application was created by BCDC to support the Long Term Management Strategy for the Placement of Dredged Material in the San Francisco Bay Region (LTMS) program and the National Marine Fisheries Service’s 2011 LTMS Programmatic Essential Fish Habitat (EFH) consultation. The web application can assist project planners in identifying potential impacts of dredging projects in San Francisco Bay to eelgrass based on the LTMS EFH consultation. Once inside the application, click on the “about” button to learn more about assessing impacts and make sure to refer to the EFH consultation linked above for more specific information. Layers in this application include: 1) the maximum extent of eelgrass beds that have been surveyed in San Francisco Bay shown in green; 2) a 45-meter growth buffer for potential bed expansion shown in blue; and 3) a 250-meter turbidity buffer around the 45-meter buffer for determining indirect impacts. The eelgrass survey data used in this web application represents the best available data on comprehensive eelgrass extent throughout San Francisco Bay as of 2021. The original eelgrass survey data were developed by Merkel & Associates, Inc. (Merkel) using a combination of acoustic and aerial surveys and site-specific ground truthing. This web application may be used to determine potential direct and indirect impacts to eelgrass habitat from dredging projects as described in the LTMS EFH consultation. These data do not replace the need for site-specific eelgrass surveys as directed by the regulatory and resource agencies.Data from the 2003, 2009, and 2014 baywide eelgrass surveys and associated Merkel reports, which include information on mapping methodology, are available for download on the San Francisco Estuary Institute’s (SFEI) website. Data from a Richardson Bay survey conducted by Merkel in 2019 is also included in this application. For further information on methods used here please enter the application by clicking “View Application” on the right, then click the “…” next to each layer, and then select “Show item details" in the drop-down menu for each individual layer.