Transient analysis of the Detroit River by the implicit method

A hydraulic transient model of the Detroit River is developed by using the implicit method to solve the complete equations of continuity and motion. The river is modeled in the shape of a Y and has one main channel and two branching channels. The stability of the numerical solution, which uses the Newton-Raphson algorithm, is found to be dependent on the selection of a weighting coefficient. This coefficient determines the position at which the equations are evaluated on the X-t grid. The model inputs consist of water surface hydrographs at the head and mouth of the river. The outputs consist of flows at each end of the three channels and water surface elevations at the junction of the Y. Transient flows of the Detroit River induced by a severe wind tide on Lake Erie were simulated to illustrate the model. Good agreement was obtained between measured and computed water surface elevations at the junction of the Y.