Using Ground Based LiDAR to Quantify Bluff Erosion in the LeSueur River Watershed in Southern MinnesotaAmerican Geophysical Union, Fall Meeting 2008 (2008)
AbstractPreliminary studies indicate that bluffs contribute 31-80% of the total annual suspended sediment load for the LeSueur River basin. In an effort to improve this estimate and better quantify the types and locations of bluffs contributing the most sediment, various remote sensing techniques are being utilized. Bluff height, steepness, and location were measured using aerial LiDAR. This is the best way to objectively map bluffs in the watershed and to quantify attributes of each bluff. Aerial photographs from 1938 and 2006 add a historical dimension, allowing us to determine where bluffs have undergone significant erosion over the past 70 years. For one bluff studied erosion rates were on average 31 centimeters per year over the 68 year period. Because these photographs cover the entire study area, erosion rates from rapidly eroding bluffs throughout the watershed can be estimated. In order to be analyzed using this method the bluffs must be eroding at a minimum rate of 14 cm/year. Error is generated by the equations used to warp the photo when georeferencing and by the accuracy of which the user is able to line up control points. Two methods of error analysis have indicated that error of approximately 8-12 meters can be expected from georeferencing the 1938 aerial photos; this error is reduced as more control points are used and when the area being inspected is close to a control point. . The aerial LiDAR and historical photographs were also used to select a variety of bluffs to survey in more detail using ground-based LiDAR, which offers centimeter-scale resolution. The detail in these data make annual changes possible to detect on select bluffs. Combining these data sets will give a more accurate estimate of the overall volume of bluff erosion in this watershed and the details of where and how that erosion is occurring.
Citation InformationPatrick Belmont, S S Day, K Gran, C Jennings, et al.. "Using Ground Based LiDAR to Quantify Bluff Erosion in the LeSueur River Watershed in Southern Minnesota" American Geophysical Union, Fall Meeting 2008 (2008)
Available at: http://works.bepress.com/patrick_belmont/90/