Optimum stable channel geometry design using imperialist competitive algorithm

Abstract

Certainly in river engineering design and planning studies, especially studies of rivers improvement, one of the challenges is prediction of stable cross-sectional hydraulic geometry in which the rate of erosion and sediment transport is in a regime state. In this study, an optimization–simulation model is developed to predict the response of alluvial bed rivers and design of their stable hydraulic geometry. The model contains an analytical model which is coupled with the imperialist competitive algorithm. Analytical simulation model uses the governing equations which describe the movement of water and sediment along the channel, calculate the distribution of the shear stresses and assess bank stability considering the effect of vegetation. Two hypotheses of maximum sediment transport capacity and minimum stream power are used as auxiliary equations to find the optimum dimensions of stable channel. The river channel responses predicted by the model are shown to agree with observations and empirical regime equations. Application of the imperialist competitive algorithm in a stable channel hydraulic geometry design reduces computational complexity and makes it possible to take into account more parameters with reasonably good results.