TEEN: Mapping and Analysing Historical Shoreline Changes Using GIS
Understanding coastal change has become increasingly important to the 78 coastal communities in Massachusetts. About half of Massachusetts’ 6.2 million residents now live in the coastal zone, and the coastal population is growing rapidly. Erosion threatens beachfront houses and development along much of the state’s 2400 km of shoreline, creating a critical need for the government and the public to have accurate, up-to-date information on shoreline change. Prior to this shoreline change update, however, Massachusetts’ existing historical shoreline change database had not been updated since 1978. New maps and data displaying longterm and more recent trends of shoreline behaviour increase the capability for sound decision-making and enhance public awareness of coastal change in Massachusetts. To produce the necessary maps and data, we compiled historical shoreline positions in ArcInfo from a variety of map and aerial photograph sources. We generated 1:10,000 scale maps of the Massachusetts coast that display historical shorelines, rates of change, locations of rate-of-change measurements (transects), and orthophotographs. We also enhanced a Microsoft Access database created by Van Dusen (1996) that contains transects, dates, and rates of change; it can be used to perform spatial queries and to compile regional statistics and trends. The Massachusetts Office of Coastal Zone Management (MCZM) will distribute these maps, along with the data tables and a manual describing how to use the information, to regional government offices and coastal communities. These products will also be made available to the public through the Internet.