Simulation of Natural River Flow by a Three-Dimensional Hydrodynamic Model

A fully calibrated three-dimensional hydrodynamic model, namely Curvilinear Hydrodynamics in 3-Dimensions (CH3D), has been developed to determine changes of flow velocity in a natural river. The objective of this paper is to present the application of the CH3D modeling. A grid scheme was constructed by using SMS software along an example river-the Detroit River from Lake St. Clair to Lake Erie with two natural curved banks as the transversal boundaries. The water depth (vertical σ-) was divided into several layers from water surface to the river bottom. A modification to the program was made by the authors to enable flexible Manning´s roughness by applying the Strickler´s formula. The National Oceanic and Atmospheric Administration (NOAA, USA) bathymetry data were post-processed for water level corrections by using Maplnfo software. The data were also extended to areas where there were no NOAA measurements in the Detroit River basin. Modeling results show that computed velocities and velocity measurements at various river cross-sections are in a good agreement typically below 10% error. Comparison between the computational water surface elevations versus that of records in gauge stations along the Detroit River is also in a good agreement.