SF Bay Eelgrass 45m Buffer (BCDC 2020)

This layer is a 45-meter growth buffer surrounding the maximum extent of eelgrass (green layer called "SF Bay Eelgrass") surveyed in San Francisco Bay. Eelgrass beds are highly dynamic and the exact location and extent of eelgrass beds can change across seasons and years. Thus, the purpose of the 45-meter growth buffer, as described in the National Marine Fisheries Service's LTMS Programmatic Essential Fish Habitat consultation is to account for areas between eelgrass patches, temporal variation in bed extent, and potential bed expansion. In cases where a dredge project intersects with the 45-meter growth buffer direct impacts to eelgrass may occur and therefore assessment, minimization, and mitigation measures may be required on a project-by-project basis.  A pre-dredge eelgrass area and density survey is required 30 days prior to the start of dredging and should be submitted to the LTMS permitting agencies. Methods for creating this layer are as follows: Downloaded Baywide Eelgrass Surveys for 2003, 2009, and 2014 by Merkel & Associates, Inc. (Merkel) from San Francisco Estuary Institute (SFEI) website. Obtained Richardson Bay 2019 eelgrass survey from Merkel. Loaded all layers into ArcGIS Pro © ESRI and re-projected all data to NAD 1983 UTM Zone 10N. Used Buffer tool to develop a single multipart shapefile with a 45-meter buffer of the input layers. Imported the Pacific Marine and Estuarine Fish Habitat Partnership (PMEP) Estuary Extent layer and clipped the 45-meter buffer over terrestrial areas based on the PEMP Estuary Extent. Some minor adjustments were made where the buffer layer resulted in fragments on land or behind levees.