Comparison of Two- and Three-Dimensional Flow and Habitat Modeling in Pool–Riffle Sequences

Abstract

Pool–riffle sequences are common bed forms in mountain rivers that have a significant effect on hydraulic and hydro-environment characteristics. Relatively few studies exist on the comparison of two and three dimensional modeling for bed forms in gravel channels. In this paper, flow structure and habitat modeling are performed in an urban river, by a two-dimensional depth-averaged finite element and a three-dimensional control volume model. Comparison of results showed that predicted velocities by SSIIM are lower than measurements data, while River2D simulations are at the same of measured magnitude. By comparing River2D-simulated shear stress and field data, we observed that estimated data are representative of field data, while the magnitude may be over-predicted compared with three-dimensional modeling. Habitat modeling showed maximum used area for River2D velocity modeling. In contrast, SSIIM simulations overestimate the depth of used area values in comparison with River2D.