ASSESSING MULTIPLE SCALE GROUNDWATER–SURFACE WATER EXCHANGE IN COARSE-GRAINED FLUVIAL STREAM SYSTEMS

Large gravel bedded rivers and their associated fluvial floodplain sediments allow for multiple areas and mechanisms of the physical transfer of river water to adjacent groundwater and floodplain groundwater to streams channels. Hyporheic exchange in and near the channel also occurs at multiple scales. Attempts at assessing rates and timing of these different scales of exchange is examined using radon, fine scale discretization of hydrogeologic properties including borehole dilution, interval slug tests, and temperature sensors. Results of characterization attempts at the meter to 10's m scale are addressed.