Response of Lake Michigan Beaches and Bluffs to a High-Magnitude Storm
Mentor 1
J. Elmo Rawling III
Location
Union Wisconsin Room
Start Date
5-4-2019 1:30 PM
End Date
5-4-2019 3:30 PM
Description
Recent high-water levels in Lake Michigan are causing erosion along the Lake Michigan shoreline and are a concern for beach managers at Point Beach State Forest. Drone-mounted cameras and Structure-from-Motion (SfM) photogrammetry software provides an opportunity to construct high-resolution digital elevation models. The purposes of this study were: 1) To adapt established methodology used for bluff surveying and identify the suitability of these techniques for a beach environment 2) To characterize the spatio-temporal changes to beach morphology and compare these to contemporaneous changes to coastal bluffs. Surveys were carried out before and after a significant storm event using a drone to collect aerial photographs of the site. For each survey multiple Ground Control Points were collected, using either Real Time Kinematic or Differential GPS units, and post-processed to allow for centimeter-scale accuracy in the final model. Agisoft PhotoScan was used to run SfM algorithms and construct a 3D model of the site. ArcGIS was used to create Digital Elevation Models and run difference calculations. The results of this study indicated several differences in methodology for image acquisition required for beach environments. Additionally, this method was not ideal for characterizing changes to the nearshore due to strong interference signals from periodic wave run-up or very shallow water. Ground observations made during the survey showed significant changes to the nearshore that were not readily characterized in the digital models. Despite these limitations, drone-based surveying using SfM provides a relatively inexpensive way to survey shoreline environments that can be deployed quickly, allowing for the frequent characterization of shoreline evolution.
Response of Lake Michigan Beaches and Bluffs to a High-Magnitude Storm
Union Wisconsin Room
Recent high-water levels in Lake Michigan are causing erosion along the Lake Michigan shoreline and are a concern for beach managers at Point Beach State Forest. Drone-mounted cameras and Structure-from-Motion (SfM) photogrammetry software provides an opportunity to construct high-resolution digital elevation models. The purposes of this study were: 1) To adapt established methodology used for bluff surveying and identify the suitability of these techniques for a beach environment 2) To characterize the spatio-temporal changes to beach morphology and compare these to contemporaneous changes to coastal bluffs. Surveys were carried out before and after a significant storm event using a drone to collect aerial photographs of the site. For each survey multiple Ground Control Points were collected, using either Real Time Kinematic or Differential GPS units, and post-processed to allow for centimeter-scale accuracy in the final model. Agisoft PhotoScan was used to run SfM algorithms and construct a 3D model of the site. ArcGIS was used to create Digital Elevation Models and run difference calculations. The results of this study indicated several differences in methodology for image acquisition required for beach environments. Additionally, this method was not ideal for characterizing changes to the nearshore due to strong interference signals from periodic wave run-up or very shallow water. Ground observations made during the survey showed significant changes to the nearshore that were not readily characterized in the digital models. Despite these limitations, drone-based surveying using SfM provides a relatively inexpensive way to survey shoreline environments that can be deployed quickly, allowing for the frequent characterization of shoreline evolution.
