This orange layer shows a 250-meter turbidity
buffer of the blue 45-meter growth buffer (blue layer called "SF Bay Eelgrass 45m Buffer") adjacent to the maximum extent
eelgrass survey in the San Francisco Bay. When a dredging project’s footprint
overlaps with this 250-meter buffer, indirect impacts to eelgrass are assessed
and best management practices are required per the National Marine Fisheries Service's LTMS Programmatic Essential Fish Habitat consultation. Methods for creating this layer are as follows: Downloaded Bay-wide Eelgrass Surveys
for 2003, 2009, and 2014 by Merkel & Associates, Inc. (Merkel) from SFEI.
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 2003, 2009, 2014, and 2019 survey data . 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 (this
represents the 45-meter eelgrass buffer layer also found in this Web
Application). To create the 250-meter turbidity buffer from there, the same
methods were used as follows. Used Buffer tool to develop a single multipart
shapefile with a 250-meter buffer from the 45-meter buffer layer. Clipped the
250-meter turbidity buffer over terrestrial areas based on the PEMP Estuary
Extent. Some minor adjustments were made where the 250-meter turbidity buffer
layer resulted in fragments on land or behind levees.
