2023 CSDMS meeting-113
The role of streambed hydraulic conductivity on near-bed surface velocity
Angel Monsalve, (he/him),University of Idaho Boise Idaho, United States. firstname.lastname@example.org
Brandon Hilliard, University of Idaho Boise Idaho, United States. email@example.com
Jeff Reeder, University of Idaho Boise Idaho, United States. firstname.lastname@example.org
Daniele Tonina, University of Idaho Boise Idaho, United States. email@example.com
Subsurface flow dynamics are largely controlled by pressure gradients generated by surface flow and differences in permeability. In most models, surface and subsurface flows are decoupled, with effects on one another only considered over relatively large time scales. However, at smaller time scales, these two flows interact and modify each other's structures and properties. In this study, we developed a fully-coupled free-surface/subsurface Large Eddy Simulation model to investigate the spatiotemporal variations in velocity and pressure, particularly near the bed surface. We validated our model by comparing it to experimental data from a laboratory simulation of open channel flow on a simulated salmon redd bed made of coarse granular sediment, using non-toxic index-matched fluid and stereo Particle Image Velocimetry (PIV). Our model accurately captured subsurface flow lines, velocity magnitude and direction, and superficial velocity profiles throughout the water column. With our validated model, we investigated the effects of subsurface hydraulic conductivity on the whole flow field.