Methodology for predicting maximum velocity and shear stress in a sinuous channel with bendway weirs using 1-D HEC-RAS modeling results

Abstract

The Middle Rio Grande is a 29-mi reach of the Rio Grande River in central New Mexico that extends from downstream of Cochiti Dam to Bernalillo, New Mexico. A series of anthropogenic factors including the construction of flood control levees and Cochiti Dam have altered the historically-braided morphology of the Middle Rio Grande to a more sinuous, degrading reach, with less overall channel migration within a natural floodplain area. Concentration of flow within an incised channel has caused areas of bank erosion and threatened riverside infrastructure, farmland productivity, irrigation systems, levee function, aquatic habitat, and riparian vegetation. Colorado State University (CSU) constructed an undistorted 1:12 Froude scale, fixed bed, physical model consisting of two channel bend geometries that are characteristic of the Middle Rio Grande reach below Cochiti Dam. Small rock structures extending from the outer bank of the bend into the main channel, referred to as bendway weirs, were constructed within each bend to research methods of stabilizing the outer bank with minimal disruption of sensitive habitat and riparian vegetation.

Citation

Sclafani, Paul. 2011. Methodology for predicting maximum velocity and shear stress in a sinuous channel with bendway weirs using 1-D HEC-RAS modeling results. Fort Collins, CO: Colorado State University. 366 p. Thesis.