129-37 Landslide Differencing Using Lidar in Floracliff Nature Sanctuary

Abstract:

Floracliff Nature Sanctuary, located in central Kentucky, is in an area with steep slopes and narrow valleys that are conducive to rainfall-triggered landslides. A recent slide impacted a trail upslope of Elk Lick Creek, causing concern for visitor safety and environmental impact. To support the sanctuary managers’ evaluation of trail safety and maintenance planning, we characterized the landslide morphology and evaluated its activity using multitemporal lidar differencing. We acquired unmanned aerial vehicle (UAV) lidar data through two flights completed three months apart to examine possible topographical change over short time scales. Laser point clouds from these two flights, as well as data from statewide point clouds, were compared using CloudCompare software and the multiscale model-to-model cloud comparison (M3C2) tool. The resulting difference output was then rasterized and analyzed in ArcGIS Pro over a multidirectional hillshade, and a polygon was added to the map to indicate the landslide's extent.

Additionally, we explored precipitation data for recent years from two adjacent weather stations to find anomalous rain events that may have contributed to the landslide initiation. Based on an anomaly recorded by the weather stations and corroborated by sanctuary staff reports, the landslide most likely occurred between April 3 and April 7, 2025. While flight data quality due to leaf-on conditions prevented quantification of short-term changes using lidar differencing, this research supported extent mapping and characterization of this landslide and its impacts on Floracliff Nature Sanctuary while also contributing to a broader understanding of the environmental conditions that trigger landslides. Detailed landslide analyses like these may ultimately improve the identification of areas susceptible to future slope failures.

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