Quantifying Lateral Bedload Transport Induced by Porous Vanes Using Submerged High-resolution Laser Scan

Submerged vanes are small, angled in-stream structures designed to redirect sediment by generating secondary flow circulations. In this study, we experimentally investigated the performance of an array of porous vanes in a laboratory flume, focusing on the lateral displacement of sediment induced by the vanes. Porous plates were chosen to minimize local scour and anchoring requirements while effectively redirecting flow, bedforms, and sediment laterally. The experiments were conducted in a 75 m long, 2.75 m wide open channel at the Saint Anthony Falls Laboratory, University of Minnesota. High-resolution 3D bed elevation data were continuously captured using a state-of-the-art submerged laser scanner. First, bedload transport rates in the streamwise direction were calculated based on bedform geometry and migration velocity, which were extracted from bathymetric data using a custom tracking method. These rates were then spatially distributed over the monitored area using a novel Eulerian-averaged grid-mapping approach to compute the two-dimensional, time-averaged bedload transport rates. This allowed us to propose a new methodology to estimate the lateral bedload transport using control volume theory and applying mass conservation. This quantitative assessment demonstrates that the vane array effectively controls lateral sediment transport distribution, suggesting that porous vanes could serve as a viable alternative for sediment management and river training. Furthermore, the proposed methodology for quantifying lateral sediment transport, combined with bedform tracking, could be broadly applied to other river engineering and geomorphological studies focused on sediment transport monitoring, thereby hopefully appealing to a broader research community.