Author: Anzy Lee, Belize Lane – Utah State University
Title: Characterizing channel variability functions using spectral analysis
Abstract: Characterizing the sub-reach scale depth and width variability of a river channel is crucial as it controls reach-scale geomorphic, hydrologic, and ecological processes. Across channel types, bed and width undulations showed low-frequency dominated oscillations (i.e. larger terrain features) with increasing water stage and with increasing average channel width. For width undulation, partly-confined braided channels exhibited thelowest frequency dominated variation whereas unconfined uniform channels exhibited the highest frequency dominated variation. Finally, coherence analysis revealed that the width and bed elevation are in-phase and strongly correlated. These findings suggest that the terrain resolution needed to represent critical morphological features varies with channel size and type, and can be used to prioritize future acquisition of channel and floodplain data. Study results can improve representation of 3d channels in large-scale hydrologic and hydraulic models by including more realistic sub-reach variability patterns and roughness elements with limited high-resolution data. Ultimately, this work has the potential to improve predictions of streamflow, hydraulics, and habitat conditions from reach- to watershed-scales with limited resource requirements.