What is Marsh Crust?
Before 1900, the areas now occupied by Alameda Point and Bayport were tidal marshlands. Between 1900 and 1940, these marshlands were filled with dredge material. Marsh Crust is the underground layer that is remnant of the tidal marshes and the fill material used to create dry land. This layer contains elevated levels of petroleum-related substances which may pose an unacceptable risk to human health and the environment if excavated and brought to the surface and handled in an uncontrolled manner.
Marsh Crust Permit
Prior to digging in the marsh crust tidal zone (See Marsh Crust Map) you must first determine the depth of your digging. The Marsh Crust Map establishes safe threshold depths with elevations above which there is little likelihood that Marsh Crust will be encountered. If your digging remains above the identified threshold depth, no permit is required. However, if you will be digging below the threshold depth, a Marsh Crust Permit will be required. For more information about the requirements of a Marsh Crust permit please see the links below.
Marsh Crust ERM Memo, February 2009
Marsh Crust Map of Alameda Point
