A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 1990

Analytical solutions were determined to predict changes in bed levels of an alluvial channel when the upstream sediment supply in stopped or when the downstream end bed level drops. These solutions were determined by solving the continuity and momentum equations of flow and sediment transport. Two approaches were considered. The first so called the parabolic modeling considers that the friction slope in the flow momentum equation is equal to the bed slope. The second approach so called the hyperbolic modeling considers the friction slope equal to the water surface slope. The analytical solutions determined in this study are compared with the experimental data in this study and those given by Newton (1951) and also with the previous analytical solutions determined by De Vries (1973) and Gill (1983). The results of the comparison verifies the ranges of applicability given by Ribberlik (1984) of the parabolic and hyperbolic models. In general it is found that the solutions of hyperbolic model provide an more accurate prediction of changes in bed level with time than the parabolic model in the region near to the source of bed change. In the region far from the source of bed change, both models predict equally good.