Simulation of lateral migration of All American Canal with semi-two dimensional sediment transport model

Abstract

The All American Canal transports water to southern California. There are two channels, the old one without lining and new one with lining to save water from the seepage loss. During the construction of the new canal, excavated sediments were piled on the right and left side banks of the old canal and the road between the new and old canals. Sediments fell into the old canal due to wind and gravitational forces. These sediment inputs to the old canal caused the flow to meander and the formation of side and middle bars. Numerical simulation of the lateral channel change was conducted using a semi-two dimensional model, GSTARS4, which is based on the stream tube concept and the theory of minimum energy dissipation rate. Both steady and unsteady flow simulations did not have significant difference of channel geometry. Application of theory of minimum energy dissipation rate, combined with stream tube concept, resulted in lateral migration of the channel, which cannot be simulated with truly one dimensional models, such as HEC-RAS and Fluvial-12. Channel meandering and the formation of middle bars were found from the semi-two dimensional GSTARS4 modeling.