HR: 0800h
AN: H41A-0121    [Abstracts]
TI: Boundary Shear Stress Along Vegetated Streambanks
AU: * Clark, L A
EM: lclark3@vt.edu
AF: Biological Systems Engineering, Virginia Tech, 200 Seitz Hall (0303), Blacksburg, VA 24061, United States
AU: Wynn, T
EM: tesswynn@vt.edu
AF: Biological Systems Engineering, Virginia Tech, 200 Seitz Hall (0303), Blacksburg, VA 24061, United States
AB: Sediment, a leading cause of water quality impairment, damages aquatic ecosystems and interferes with recreational uses and water treatment processes. Streambank retreat can contribute as much as 85% of watershed sediment yield. Vegetation is an important component of stream restoration designs used to control streambank retreat, but vegetation effects on streambank boundary shear stress (SBSS) need to be quantified. The overall goal of this experiment is to predict boundary shear stress along vegetated streambanks. This goal will be met by determining a method for measuring boundary shear stress in the field along hydraulically rough streambanks, evaluating the effects of streambank vegetation on boundary shear stress in the field, and developing predictive methods based on measurable vegetative properties. First, three streambank vegetation types (herbaceous, shrubbery, and woody) will be modeled in a flume study to examine both boundary shear stress measurement theory and instruments for field use. An appropriate method (law of the wall, Reynold's stresses, TKE, or average wall shear stress) and field instrument (ADV, propeller, or Pitot tube) will be selected, resulting in a field technique to measure SBSS. Predictive methods for estimating SBSS, based on common vegetation measurements, will be developed in the flume study and validated with field data. This research is intended to improve our understanding of the role of riparian vegetation in stream morphology by evaluating the effects of vegetation on boundary shear stress, providing insight to the type and density of vegetation required for streambank stability. The results will also aide in quantifying sediment inputs from streambanks, providing quantitative information for stream restoration projects and watershed management planning.
DE: 1856 River channels (0483, 0744)
SC: Hydrology [H]
MN: 2007 Fall Meeting