PLANNING FOR SEA LEVEL RISE IN MARYLAND: THE ROLE OF THE STATE GEOLOGICAL SURVEY

For its size, Maryland has a disproportionately long shoreline - 6400 km in the Chesapeake Bay alone. Coupled with a recent rate of sea level rise that is nearly twice the global average and low-lying land that is composed of unconsolidated coastal plain sediments, shoreline erosion is a continuing problem. Often not as dramatic the massive storm induced erosion on ocean coastlines, erosion in the Chesapeake Bay tends to be slow, persistent, and inevitable. While the effects of this erosion have been recognized, little concerted effort has been directed at planning for continued sea level rise. Much of the public and elected officials lack an understanding of, and appreciation for, the seriousness of shore erosion in the Chesapeake due, in part, to its undramatic nature. Recently, however, state officials have become more concerned with developing a coordinated strategy to address this significant management issue. One identified component in that planning effort is the need for additional technological, data, and research support, as well as public education and outreach.

For the past 100 years, the Maryland Geological Survey (MGS) has been the lead agency in documenting shoreline changes. Periodically, survey researchers have compared shoreline positions and delineated areas undergoing similar rates of change. In the past decade, MGS has advanced this process into the GIS realm by compiling digital historical shorelines derived from coastal survey maps and orthophotography. In support of the identified planning need, MGS is using these digital data to develop estimates of land loss by county and by watershed, and quantifying linear rates of erosion along closely-spaced, shore-normal transects. In the near future, MGS intends to combine linear and areal land loss information with high resolution elevation data (e.g., derived from LIDAR), to determine volumetric losses, and to characterize the grain size composition and nutrient content of eroding shores to determine the sediment and nutrient load to the surrounding water bodies. The combination of high resolution maps, readily available GIS products and associated sediment data will serve to educate the public and elected officials, determine the potential effects on public infrastructure, and document the ecosystem consequences of shoreline erosion.