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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 110, F04023, doi:10.1029/2005JF000322, 2005

Modeling effects of bank friction and woody bank vegetation on channel flow and boundary shear stress in the Rio Puerco, New Mexico

E. R. Griffin

U.S. Geological Survey, Boulder, Colorado, USA


J. W. Kean

U.S. Geological Survey, Boulder, Colorado, USA


K. R. Vincent

U.S. Geological Survey, Boulder, Colorado, USA


J. D. Smith

U.S. Geological Survey, Boulder, Colorado, USA


J. M. Friedman

U.S. Geological Survey, Boulder, Colorado, USA


Abstract

We have applied a physically based model for steady, horizontally uniform flow to calculate reach-averaged velocity and boundary shear-stress distributions in a natural stream with woody vegetation on the channel banks. The model calculates explicitly the form drag on woody plant stems and includes the effects of vegetation on the boundary shear stress, velocity, and turbulence fields. Average channel shapes, bed gradients, and shrub characteristics were determined for four long, internally similar reaches covering an 81-km segment of the lower Rio Puerco, in north-central New Mexico. Hydraulic geometries for each of three flow events were determined from reach-average channel shapes, slopes, and measured silt-line heights above the bed. Model results show that friction on the lateral boundaries reduced the boundary shear stress in the center of the Rio Puerco channel by as much as 20%. In reaches with moderate to dense bank shrubs, perimeter-averaged boundary shear stresses were reduced by almost 40% during near bankfull flows. Model-calculated discharges for all three flow events indicate there was a loss of about 40% of the upstream discharge through the 81-km river segment. Infiltration rates estimated from discharge losses during the quasi-steady peak flows and areas of the bed and banks suggest rates of flow loss into the silty sand of the upper banks are about 8 times greater than rates of loss into the clayey silt-covered bed and lower banks.

Received 5 April 2005; accepted 20 September 2005; published 14 December 2005.

Keywords: bank vegetation; channel friction; stream channel flow.

Index Terms: 1847 Hydrology: Modeling; 1856 Hydrology: River channels (0483, 0744); 1860 Hydrology: Streamflow; 1838 Hydrology: Infiltration; 1825 Hydrology: Geomorphology: fluvial (1625).

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Citation: Griffin, E. R., J. W. Kean, K. R. Vincent, J. D. Smith, and J. M. Friedman (2005), Modeling effects of bank friction and woody bank vegetation on channel flow and boundary shear stress in the Rio Puerco, New Mexico, J. Geophys. Res., 110, F04023, doi:10.1029/2005JF000322.