Using a LiDAR-Derived DEM to Delineate Surface Drainage Pathways and the Contributing Watershed of Murphy’s Pond

Rainfall-driven runoff represents a key hydrological pathway linking terrestrial land use to aquatic carbon cycling. Understanding the topographic pathways connecting agricultural lands to receiving water bodies is therefore important for assessing potential runoff contributions. This study used a high-resolution Light Detection and Ranging (LiDAR)-derived digital elevation model (DEM) to map potential surface drainage pathways and estimate the contributing surface watershed area of Murphy’s Pond, a wetland-buffered pond in western Kentucky. LiDAR-derived DEM tiles were mosaicked to create a continuous elevation surface, from which a hillshade was generated to examine local terrain. Hydrological analysis in ArcGIS Pro included depression filling, D8 flow-direction modeling, and flow-accumulation analysis. Drainage networks were extracted using multiple flow-accumulation thresholds to evaluate differences in the distribution and density of modeled drainage pathways. These pathways were examined alongside pond boundaries, wetland features, and land-use data to investigate potential surface-drainage connections between surrounding agricultural fields and the pond. The subsequent watershed delineation and land-use overlays were used to estimate the extent and composition of the contributing area, with particular attention given to agricultural land and intervening forested and wetland areas. Analysis of the results provided a terrain-based assessment of potential agricultural surface-runoff connectivity to Murphy’s Pond and established a spatial foundation for future investigations of rainfall-driven hydrological processes. The findings represented potential topographic drainage patterns rather than direct measurements of runoff or confirmed pollutant transport.