Prediction of Longitudinal Dispersion Coe cient in Natural Channels Using Soft Computing Techniques

Accurate estimate of longitudinal dispersion coe cient is essential in many hydraulic and environmental problems such as intake designs, modeling ow in esturies and risk assessment of injection of hazardous pollutants into river ows. Recent research works show that in the absence of knowledge about explicit relationships concerning longitudinal dispersion coe cient and its in uencing parameters, data driven techniques can be used to predict it with reasonable degree of accuracy. In this paper, the usefulness of Support Vector Machines (SVM) and Genetic Programming (GP) are examined for predicting longitudinal dispersion coe cient in natural channels. The hydraulic variables such as ow depth (H), ow velocity (U) and shear velocity (u ) along with the width of channel (B) are used as input variables to predict longitudinal dispersion coe cient (Kx). The performance evaluation based on multiple error criteria con rm that GP shows remarkably good performance in capturing non-linear relationship between the predictors and predictant in the estimation of longitudinal dispersion coe cient when compared with empirical approaches, the traditional Arti cial Neural Networks (ANN) and SVM. Hence GP can be used as an e cient computational paradigm in the prediction of longitudinal dispersion coe cient in natural channels.