Short- and long-term perspectives on the evolution of a Lake Michigan foredune

The evolution of Great Lakes coastal dunes includes long-term trends and short-term variations. This study explores multi-year, interannual and seasonal patterns of change as a Lake Michigan foredune responds to variations in lake level, weather and surface conditions. The study site is an active foredune in P.J. Hoffmaster State Park on the east coast of Lake Michigan. Foredune changes, local conditions and processes were monitored from 2000 to 2012 with repeated ground surveys, erosion pins, microclimate measurements, and observations of surface conditions. Additional weather and lake-level data were obtained from regional sources. Study results show a trend of foredune growth during the multiyear study period, with interannual and seasonal variations in the rates and spatial patterns of dune growth. At the scales of investigation, relationships between dune change and variables could not be quantified, but patterns of foredune change and influential variables were identified. The greatest amounts of erosion and deposition took place during the autumn and winter when strong winds were the most frequent, but storm conditions, vegetation changes, precipitation, snow, and ground freezing affect the availability of sand for transport by wind. Study results suggest that event-scale research is needed for understanding interactions between variables and the foredune, but mesoscale studies such as this one are crucial for identifying cumulative patterns of dune change and the role that events play in the larger scale patterns of dune evolution.