SHORT-TERM MONITORING OF AN ACTIVELY MIGRATING COASTAL DUNE - INTEGRATING LIDAR AND FIELD-BASED GPS TECHNOLOGIES

The coastal dunes of northwest Indiana, along the southern shore of Lake Michigan, are part of the formally defined Tolleston Beach that preserves coastal features and deposits associated with the Nipissing phase and post-Nipissing coastal development. While previous geologic studies have evaluated the late Holocene history and chronology of dune-building in Lake Michigan, there remains a need to understand how modern processes are impacting dune migration and dune morphology. Mount Baldy in the Indiana Dunes National Lakeshore is an extreme example of a rapidly migrating parabolic dune that is advancing over a previously stabilized and forested landscape due to complex disturbance factors including restricted longshore sediment supply, vegetation loss caused by visitor traffic, storms, and water-level variability. The management, stabilization and restoration of coastal resources like Mount Baldy require monitoring approaches and technology that can detect short-term and small-scale changes in sediment movement and landscape topography. If frequent monitoring is required, there is the added need for cost-effective technologies that can provide sequential data. This project provides an example of how elevation data obtained by airborne LIDAR and field-based real-time GPS mapping can be combined to formulate a monitoring plan to evaluate topographic and geomorphic changes in rapidly changing coastal parabolic dunes. Data collected from 2010 to 2014 provide evidence for a shift in the orientation of the dune’s long axis, measurable changes in the position of the basal slipface, and allow for mapping of maximum erosional and depositional zones across the dune’s stoss slope. This approach provides an opportunity to investigate topographic change at different spatial and temporal scales to generate data that can guide management decisions aimed at landform stabilization and restoration and can allow researchers to investigate broader questions of landscape response to complex and interrelated disturbance factors.