Figure 4. HydroGeoSphere simulated exchange rates across the water-sediment interface and water-jam interface for the eight scenarios where the logjam permeability, quantity of logjams, and/or discharge change. The area in front of each logjam is the hotspot for surface water infiltration, while the area behind the logjam is the hotspot for groundwater exfiltration. The submerged area of the flume in these scenarios are different due to changes in backwater effects. Generally, more logjams, higher flow rates, or lower logjam permeability will create more of a backwater effect and thus extend the area available for exchange with the subsurface.