Reports
Updating shore erosion rates in Maryland
2003, Hennessee, E.L., Valentino, M.J., and Lesh, A.M.
File Reports, Coastal and Estuarine Geology, File Report 2003-05
Abstract
In response to the recommendations of a Shore Erosion Task Force appointed by the Governor in 1999, the Maryland Department of Natural Resources (DNR) is developing regional shore erosion control strategies. The strategies are based, in part, on an understanding of historical rates of shoreline retreat. To provide up-to-date information regarding shoreline change in a format consistent with a widely used map series compiled in 1975, the Maryland Geological Survey (MGS) cooperated with Towson University’s Center for Geographic Information Sciences (CGIS). The collaborators had previously determined site-specific rates of change (erosion or accretion) for Maryland’s coastal shoreline using a computer program, the Digital Shoreline Analysis System (DSAS), developed by the U.S. Geological Survey. DSAS constructs shore-normal transects every 20 meters along shore. Transects intersect a series of historical shorelines. Based on the time elapsed and the distance between shorelines, DSAS calculates a rate of change for each transect. For Maryland, DSAS generated nearly 250,000 transects. During this last phase of the project, the partners generalized the DSAS results and assigned rate-of-change attributes (i.e., accretion, 0-2 ft/yr of erosion, 2-4 ft/yr of erosion, etc.) to a recent (1988-1995) digital shoreline for Baltimore City and the State’s 16 coastal counties. The attributed files provide a visually simple summary of the much larger database of shoreline rates of change. They will be useful to coastal researchers and managers in need of general information about shoreline advance and retreat.
