UAV Lidar-Based Debris Basin Capacity Assessment Following the 2025 Eaton Wildfire and the Presidents' Weekend Storm, Los Angeles County

In the aftermath of the January 2025 Eaton and Palisades wildfires in Los Angeles County, assessing the remaining capacities of debris basins is critical for forecasting potential hazards associated with upcoming rain events. This report provides a low-cost, efficient assessment of debris basin capacities using UAV-based lidar surveys to provide high-resolution topographic data. One to five surveys were made for 14 debris basins in the Eaton Fire area, which capture for some basins their debris-holding capacity immediately following wildfire and before rainfall and the capacity following the Presidents’ Day weekend storm event (February 13-15). For some basins surveys were repeated following the storm to assess if significant dewatering had occurred (i.e., to better measure debris volumes vs. water volumes).