Landslide Monitoring at Maxey Flats Disposal Site, Kentucky FY2024-2026

Landslide Monitoring at Maxey Flats Disposal Site, Kentucky FY 2024–2026 The Maxey Flats Disposal Site is a low-level nuclear waste disposal facility in Fleming County, Kentucky operated by the Kentucky Division of Waste Management. Although no longer accepting waste for burial, the facility continues to maintain the construction cap, evaluate the site drainage system, monitor water quality, and monitor hillslope erosion. Several landslides have been documented along the slopes below and adjacent to the facility cap. To quantify landslide movement and assess the hazard, the Kentucky Geological Survey (KGS) completed two rounds of Unmanned Aerial Vehicle (UAV) flights in spring 2023 and winter 2024 that acquired light-detection and ranging (lidar) data. KGS used the lidar data to derive high-resolution elevation maps, differenced the elevations across the slope over time, and calculated slope movement. The KGS plans to continue UAV-based lidar acquisition for the state fiscal year 2024–2026. KGS will plan the flight missions, conduct 4 rounds of flights across the area of interest (two rounds per project/fiscal year that bracket the end of leaf-on and beginning of leaf-on), and process the LiDAR data. We will assess slope movement by using generated digital elevation models in order to conduct elevation differencing and quantify slope movement over time. A particular focus will be on the toe slopes as those areas historically been active. Evaluating the possibility of retrogressive displacement further upslope near the ridgetop will also be evaluated. Maxey Flats officials will use the data and results to support drainage and hillslope stabilization techniques, address security of the cap, and assist with site hazard and risk assessment. Major Goals • Conduct UAV flights across the area of interest collecting lidar. Flights will be spaced out as two rounds of flights per project/fiscal year that bracket the end of leaf-on and beginning of leaf-on • Generate digital elevation models of area of interest in order to conduct elevation differencing • Monitor and quantify slope elevation changes and landslide movement over time • Draw conclusions regarding overall landslide activity during the relevant time period and provide results to Maxey Flats officials in order to support hazard and risk assessment