Simulation of a Regulated, Urbanized High-Gradient Stream

Regulated rivers present a challenge to river managers due to the presence of control structures, artificial channelization, flow regulation, and the resulting irregular sediment loading. The present study focuses on the Spokane River, Washington, USA, which is an urbanized, regulated river with high bed gradients and steep banks. Numerical flow and sediment simulation in the Spokane River is utilized here to examine multiple flow conditions that would not easily be studied in a field or lab setting. With the advancements in numerical modeling and data presentation, computer models are an attractive engineering tool. The objective of this study is to simulate the complex flow characteristics in the Spokane River through the use of two different hydrodynamic models, namely, FESWMS, which is a conservative 2-D depth-averaged model, and RMA-2, a non-conservative 2-D depth-averaged model. The best model for simulation of the Spokane River must be determined and some preliminary flow results will be produced. A set of evaluation criteria must be developed in order to make a proper choice for a simulation of this type, and this will require an in-depth examination of the underlying equations used in each model. The present study compares the utility of two hydrodynamic codes in simulating complex flows. The numerical results are compared with limited field and laboratory data.