Title: Influence of Vegetation on Streambank Hydraulics. Abstract approved: .

Proper use of vegetation in streambank bioengineering practices requires a comprehensive understanding of the influence of vegetation density on streambank hydraulics. A series of studies were conducted to investigate the relationship between independent variables vegetation density, bank angle, and discharge and dependent variables channel velocity, resistance, turbulence, and shear stress. Flume experiments were conducted varying vegetation stem density (number of plants/horizontal area) and frontal area (number of leaves/vertical area) on 30 ° and 15 ° vegetated bank-toes at three discharge rates. Three sets of 3D velocity measures were collected using an ADV at: 1) 0.6 x depth, 2) near-boundary, and 3) velocity profiles. Resistance parameters for drag coefficient (Cd) and Manning’s n were estimated. Turbulent stress measures based on turbulent kinetic energy and Reynolds stress were used to evaluate boundary shear stress. Tensor fields were visualized to explore vorticity and near-boundary hydraulics. Results demonstrated that as vegetation density increased, water was increasingly redirected from the bank-toe to the main channel, decreasing downstream velocity along the bank-toe by 35-95 % and increasing downstream velocity in the main channel by 80-240%. A