1D modeling of mud/debris unsteady flows

The National Weather Service 1D dynamic flood routing model FLDWAV is enhan ced to include capability of modeling mud/debris unsteady flows by includin g an additional friction slope term in the momentum equation of the Saint-V enant equations. Three techniques are incorporated into the model to determ ine the mud/debris related friction slope term due to the internal viscous dissipation of non-Newtonian fluids and granular sliding friction of coarse -grained debris surges. These techniques are tested and some computational results are compared with observed field data and experimental data.