The hyporheic zone is a band of permeable, saturated sediment surrounding a river, where stream flow and shallow groundwater mix. It includes riverbeds (shallow hyporheic zone), riverbanks, saturated sediments under dry bars (parafluvial hyporheic zone), and riparian and floodplain areas (floodplain hyporheic zone). It is characterized by intense physical and chemical gradients due to the mixing of groundwater and surface water by upwelling and down welling fluxes.
Hyporheic exchange (the mixing of stream flow and shallow groundwater) is poorly understood in gravel-bed rivers. These channels are particularly important habitat for salmonids, many of which are currently at risk worldwide and which incubate their offspring within the hyporheic zone.
We have been studying hyporheic exchange with laboratory experiments, numerical modeling and analytical solutions to investigate the effect of stream morphology on their hydraulic characteristics