Abstract
Discretizing the linearized characteristic equations of gradually varied unsteady flows using the backward difference method in time and the Galerkin's method in space, a numerical model for a single channel is first set up and then the system model for channel networks in flat land is graph-theoretically formulated in terms of connection matrices. This formulation is developed to facilitate the systematical computation on digital computers for large-scale complex networks. The numerical results obtained by the present method are compared for verification to observation data. The agreement between the computed and observed water levels for a flood time is satisfactory. It is further shown that this method is more advantageous than the 4-point implicit method in regard to the time required in making the computations.
