Many coastal communities in Alaska are vulnerable to erosion and lack shoreline change data to perform accurate assessments of this coastal hazard. To address this issue, the Alaska Division of Geological & Geophysical Surveys (DGGS) has developed an interactive map tool that displays historic and projected shoreline positions. This web atlas will improve vulnerability assessments and long-term management approaches for coastal communities throughout the state by enabling access and visualization of trends in shoreline position.
Historic shoreline positions in the database are derived from a range of remote sensing techniques in combination with field campaigns. The U.S. Geological Survey Digital Shoreline Analysis System (DSAS) is used to calculate rates of shoreline change, and DGGS staff have built a GIS model that extrapolates these rates of shoreline change to illustrate a projected future shoreline position (Figure 1). This model incorporates errors from the DSAS calculations, which are presented as a confidence interval surrounding the predicted shoreline (Figure 2).
Local officials are already using this tool to make more informed decisions about the managed retreat of critical infrastructure.
The dashed orange lines represent the 2035 projected shoreline uncertainty
Although this tool presents simplistic linear trends, it serves as a valuable improvement to existing resources in Alaska for identifying, prioritizing, and planning for statewide coastal erosion issues. To help educate stakeholders about the uses and limitations of these types of analyses, DGGS staff are teaming up with science illustrators from the University of Alaska Fairbanks to prepare a comprehensive companion document and the live release of this web atlas is scheduled for April 2015.
