Uncovering the hidden world of riverbed sediments: The role of sediment heterogeneity and cross-bar channel fills in the hydrogeochemical dynamics of the hyporheic zone.

Groundwater-surface water interaction (hyporheic exchange) is critical in numerous hydrogeochemical processes; however, hyporheic exchange is difficult to characterize due to the various spatial (e.g., sedimentary architecture) and temporal (e.