THE CHALLENGES AND PROMISES OF COMMUNICATING COASTAL EROSION INFORMATION

Urban development in the coastal zone is characterized by hardened surfaces that lend an illusory feeling of permanence in a naturally dynamic environment. Protected coastal areas such as the Cape Cod National Seashore foster a pattern of public use where natural processes of change are considered acceptable. Even predictable changes (road alignments, residential use, beach parking, navigation, etc) require intensive planning and community consensus. Scientists are often called upon to distill complex information with high temporal and geographical uncertainty into clear guidance for high-cost decisions. Clear and artful communication across disciplines helps ensure that resources are protected based on predictable outcomes.

Shoreline processes of erosion and accretion are familiar to the general public, but conveying long-term shoreline trends is challenging for several reasons: 1) Time scale: long-term loss is confused with erratic short-term gains and losses so that the forest is obscured by the trees. 2) Uneven geographic and temporal distribution of short-term erosion; i.e. most locations erode less than the long-term average while a few locations erode much more, thus the median value is less than the mean and probable short-term erosion at a single location is less than the long-term probable erosion at the same location. A third reason is psychological – people simply hope that shoreline loss will not occur, and that by ignoring it, it will not.

The advent of Geographic Information Systems (GIS) mapping, precision Global Positioning System (GPS) and other desktop imaging/simulation tools offers multiple methods of measuring and communicating trends in coastal change. Various graphical approaches can summarize rates of change and parse changes by location within different timeframes. GPS allows repeated seasonal and annual measurements that formerly required larger time commitments and technical skills. Aerial photography and overlay mapping create visual context for measurements. These tools help explain that coastal change feeds back and influences the future environment for change. Coastal geomorphologists will be increasingly challenged to develop applications that communicate to coastal managers and in turn, maintain the maximum public benefit from highly valued coastal resources.