T165 Physical and Biological Processes, Interactions, and Restoration in River Systems (Posters)

Tuesday, 11 October 2022
9:00 AM - 1:00 PM
Exhibit Hall F

THE EFFECTS OF WOOD DEBRIS ON STREAMBED MORPHOLOGY: SPATIAL PATTERNS OF FLUID FLOW AND SEDIMENT TRANSPORT AROUND INDIVIDUAL PIECES OF WOOD DEBRIS

Paper number: T165-5
Program: Technical Sessions
Time: 9:00 AM – 1:00 PM

Authors

Abstract

The interaction of wood debris, fluid flow, and sediment transport in rivers creates local streambed morphology, such as large pools that are important fish habitats and sediment deposits that bury and stabilize woody debris. We used two sets of flume experiments and field measurements on a gravel-bedded river to investigate how wood geometry and orientation affect local flow and scour pool formation. For the first set of experiments, fluid flow patterns on the bottom boundary layer, where bedload sediment transport occurs, were visualized using solid dye crystals. The second set of experiments and the field measurements investigated streambed morphology around wood debris, as well as distributions of wood debris geometry and orientation in nature. We find that: 1) the presence of roots on wood debris leads to greater areas of flow disturbance and sediment scour; 2) the size of scour pools and flow disturbances around wood debris increase as the root cross-sectional area, oriented orthogonal to flow, increases. A better understanding of the underlying sediment physics and fluid dynamics around naturally occurring wood debris in rivers can lead to improved hazard prediction of mobile wood during floods and to improved design criteria for engineered logjams placed to protect infrastructure and improve aquatic habitat.

Geological Society of America Abstracts with Programs. Vol. 54, No. 6

doi: 10.1130/abs/2022AM-383919

© Copyright 2022 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.