Applications of Ground Penetrating Radar for Mapping Fluvial Sediments at the East River Floodplain Near Crested Butte, Colorado

Shallow subsurface groundwater flow and hydrologic exchange is strongly controlled by floodplain sedimentology. In fluvial settings, sediment packages and their associated bedforms and grain size distributions can create preferential flow paths for subsurface water. These flow paths control how water moves both vertically and laterally through the subsurface in river corridors, which in turn affects hydrologic exchange between surface water and groundwater. Sediment packages in fluvial environments can be difficult to map using traditional methods due to their heterogeneity. Ground penetrating radar (GPR) has proven to be a powerful tool for identifying facies changes in fluvial sediments. This study pairs GPR data with sediment samples, hydraulic conductivity, and water level data from existing wells at the study area to map subsurface sedimentary structures in order to provide insight into physical controls on subsurface hydrologic exchange at the East River near Crested Butte, CO.