A LiDAR Study of Erosion and Sedimentation of Meandering Waterways

Summary form only given. Meandering waterways experience significant erosion and sedimentation especially during floods when the flow quantity considerably increases. Rivers and streams with sharp bents are regularly exposed to damages along their path as the speeding water flow erodes the concave side of the bent and deposits sedimentation on the convex side of the same. Surveying the pattern of sediment transport along lengthy water ways could require extensive effort especially if the waterway is long and/or has many twists and turns. A practical and technologically advanced way toward carrying out such a survey is to utilize LiDAR images taken along the waterway. This study was undertaken to analyze LiDAR tiles associated with sharply meandering sections along the Mohawk River in New York. The analysis was done by making a comparison at the examined sections before and after a major flooding event. The study used LiDAR rasters to model the terrain at the sections under consideration. Furthermore, digital elevation model (DEM) data was also employed to create models of the terrain prior to the major flooding event. The comparison also relied on contour maps, TINs, and LiDAR terrain simulation. It was concluded that the geometrical pattern of meandering sections is greatly impacted by major flooding events. Some of the changes that occur at a twisted section could result in a permanent irreversible damage to the waterway. A LiDAR survey could be an economical and efficient way to examine long waterways riddled with twists and turns. River sections that experience repeated erosion effects could become unstable. Identifying such sections and providing them with the necessary protection should be of high priority to prevent a landslide or a similar disaster.