Monitoring changes in a slow-moving, chronically destructive colluvial landslide in Northern Kentucky

Slow-moving, chronically destructive landslides are projected to grow in number globally in response to precipitation increases from climate change, and land disturbances from wildfire, mining and construction. In the Cincinnati and northern Kentucky metropolitan area, landslides develop in colluvium that covers the steep slopes along the Ohio River and its tributaries. This study presents a technique to utilize older datasets in combination with modern surveys to monitor slow-moving landslides over many years. In this study we quantified elevation changes in a slow-moving colluvial landslide over 14 years using a combination of countywide lidar, uncrewed aerial vehicle (UAV) structure-from-motion (SfM) surveys and a UAV lidar survey. Because the technology and quality differ between surveys, the threshold of detectable change varied for each survey combination, ranging from 5 to 20 cm (~2 to 8 inches). Record rainfall in 2011 produced the largest changes to the landslide. Since then, the landslide toe has continued to deform, and the landslide has doubled its width by extending into a previously undisturbed slope.

Image caption: Johnson, S.E., Haneberg, W. C, Crawford, M., Bryson, S., 2023, Measuring ground surface elevation changes in a slow-moving colluvial landslide using combinations of regional airborne lidar, UAV lidar, and UAV photogrammetric surveys. Quarterly Journal of Engineering Geology and Hydrogeology. https://doi.org/10.1144/qjegh2022-078.