Field Evidence of the Spatial and Temporal Variation in Bed Shear Stress in a Gravel-Bedded River
Faculty Mentor Information
Angel Monsalve, University of Idaho
Presentation Date
7-2025
Abstract
Understanding how bed shear stress varies through time and space is essential for predicting sediment transport and channel stability in gravel bedded rivers. This project will collect high resolution field measurements of water depth, flow velocity, and discharge along repeated cross sections during low flow, rising, and falling limbs of a spring–summer hydrograph. Velocity profiles will be used to compute point estimates of shear stress, which, together with measured channel geometry, will drive two dimensional river analysis modelling and produce spatial shear stress maps. Comparing these maps through successive flow stages will quantify how shear stress magnitude and distribution respond to changing discharge and help identify transient high stress zones that influence bed mobility, thereby informing better river management decisions. The work will also train undergraduate researchers in modern hydraulic instrumentation, data processing, and modelling workflows. Resulting insights will strengthen the empirical basis for sediment transport thresholds and advance the Idaho NSF I CREWS objective of improving resilience in coupled energy–water systems under climate driven hydrologic variability.
Field Evidence of the Spatial and Temporal Variation in Bed Shear Stress in a Gravel-Bedded River
Understanding how bed shear stress varies through time and space is essential for predicting sediment transport and channel stability in gravel bedded rivers. This project will collect high resolution field measurements of water depth, flow velocity, and discharge along repeated cross sections during low flow, rising, and falling limbs of a spring–summer hydrograph. Velocity profiles will be used to compute point estimates of shear stress, which, together with measured channel geometry, will drive two dimensional river analysis modelling and produce spatial shear stress maps. Comparing these maps through successive flow stages will quantify how shear stress magnitude and distribution respond to changing discharge and help identify transient high stress zones that influence bed mobility, thereby informing better river management decisions. The work will also train undergraduate researchers in modern hydraulic instrumentation, data processing, and modelling workflows. Resulting insights will strengthen the empirical basis for sediment transport thresholds and advance the Idaho NSF I CREWS objective of improving resilience in coupled energy–water systems under climate driven hydrologic variability.