COASTAL GEOMORPHOLOGICAL VECTORS OF CHANGE: APPLICATION OF MONITORING PROTOCOLS IN PARKS AND REFUGES

Coastal systems are among the most dynamic ecosystems and require periodic monitoring to assist in informed resource management decisions. With sea-level rise, more frequent storms, relative sediment availability, and other consequences of climate change becoming regular occurrences globally, it is more important now than ever to fully understand the vectors of sediment fluxes that occur along our coasts. The National Park Service and the Fish & Wildlife Service have adopted a long-term program to monitor topographical change within coastal areas of the Northeast and Mid-Atlantic. Protocols have been developed to identify the seasonal, annual, and long-term trends and variability as a basis for understanding the coastal geomorphological system using a series of metrics.

One-dimensional shoreline position is recorded seasonally using mapping-grade GPS units with sub-meter accuracy; the resulting datasets are analyzed within a GIS to determine zones of positive or negative displacement. Within each site, a series of two-dimensional beach-dune profiles show a network of elevational cross-sections. This network is analyzed within the context of the entire system to determine trends of sediment flow alongshore, identify areas of erosion and/or deposition, and establish how specific geomorphological features are evolving. Three-dimensional digital elevation models (DEMs) of the entire beach-dune system are constructed for areas of special interest. These DEMs are compared temporally to derive the volume of sediment within a system, how it changes seasonally, and how it responds to disturbance events such as major storms. The GPS equipment used to collect the 2-D and 3-D data is survey-grade, accurate to within centimeters.

These metrics are presented in annual and long-term trend reports that provide critical information on the geotemporal evolution of coastal systems. Currently, these protocols are utilized within 19 National Wildlife Refuges, 4 National Parks, and 1 National Estuarine Research Reserve. Additionally, the GIS datasets resulting from these efforts are maintained in a national geodatabase.