Geomorphic controls on hyporheic exchange across scales - Watersheds to particles

Abstract

We examined the relationship between fluvial geomorphology and hyporheic exchange flows. We use geomorphology as a framework to understand hyporheic processes and how these processes change with location within a stream network, and over time in response to changes in stream discharge and catchment wetness. We focus primarily on hydrostatic and hydrodynamic processes—the processes where linkages to fluvial geomorphology are most direct. Hydrostatic processes result from morphologic features that create elevational head gradients whereas hydrodynamic processes result from the interaction between stream flow and channel morphologic features. We provide examples of the specific morphologic features that drive or enable hyporheic exchange and we examine how these processes interact in real stream networks to create complex subsurface flow nets through the hyporheic zone.