Shore-based monitoring of flow dynamics in a steep bedrock canyon river

¹ Civil Engineering, University of Ottawa, Ottawa, Ontario, Canada, K1N 6N5
² Department of Geography, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
³ Department of Geography, University of Victoria, Victoria, British Columbia, Canada V8P 5C2

^* Corresponding author: sansa048@uottawa.ca

Abstract

The pace of landscape evolution is set by bedrock erosion in canyons. This phenomenon occurs by various geological processes including plucking of bedrock blocks and abrasion by saltating bedload and suspended load in highly turbulent flows. For a better understanding of the river flow characteristics in bedrock rivers, a comprehensive study of flow dynamics was undertaken in Black Canyon in the Fraser River, British Columbia. We used shore-based video imagery of the river to study surface flow dynamics. The shore-based monitoring system consisted of a Campbell Scientific camera mounted at the top of the canyon walls. We monitored the water surface boils due to upwelling and determined river surface flow velocities from the shore-based imagery. Automatic detection of the upwelling surface boils leads to a better understanding of the secondary circulation patterns and flow structures in this large steep river bedrock canyon. The data collection and analytical procedures developed in this research are cost-effective tools for remotely determining flow dynamics, which can be applied to other rivers.