Estimation of longitudinal dispersion coefficient for wide rivers with shallow waters and mild slope. Application of the model at Bio Bio river, Chile

Abstract

This paper presents the different simple methods to estimate the longitudinal dispersion coefficient (DL) for wide rivers, with shallow waters and mild slope. The method proposed by Mc Quivey and Keefer (1974) gives the best estimations among all the reviewed methods. A hybrid model is proposed which combines the method proposed by Liu (1977), but estimating the parameter β from a dimensionless shape coefficient (W/R). The real β values are correlated with the corresponding (W/R) through a simple regression analysis of the form Y = aXb. The proposed method has a standard average error 10% smaller than the method proposed by McQuivey and Keefer (1974). The proposed model was applied in a reach of the Bio Bio river, Central Chile.