The Influence of Bank Vegetation on Flow Structure Within a Small Agricultural Stream: Implications for Channel Stability

Vegetation growing on river banks can have significant effects on the flow, sediment transport, and ultimately channel form. Although past studies in fluvial geomorphology have largely ignored the complicated role ofinstream and bank vegetation, some recent studies have attempted to characterize flow in vegetated environments. There is, however, still a need to examine the influence of bank vegetation on flow structure and channel stability. This study seeks to investigate the influence of dense overhanging bank grasses on the three-dimensional flow structure within a sinuous reach of the Spoon River, a small inset channel at the bottom of a drainage ditch in East Central Illinois. The three-dimensional velocity data analysed in this study was collected at seven cross sections using an acoustic Doppler velocimeter. The analyses of contour and vector plots of velocity, turbulent kinetic energy, and shear stress for each cross section has revealed that the dense overhanging grasses growing on the banks have effectively shifted the high-velocity core away from the outer banks of the bends. Along with the channel geometry at this site, the grasses have contributed to the existence of a zone of stagnant and recirculating flow along the outer banks, with the high shear layer adjacent to this zone. This has protected the outer banks from much of the forces of erosion, thereby increasing the stability of this meandering inset channel.

Name thesis:degree_name

M.S. (master's)

Level thesis:degree_level

Thesis

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Massey, Kyle Donald

Contributors dc:contributor

• Rhoads, Bruce

• Agriculture
• Geography

Language dc:language

eng