Author(s): Khalil I. Othman; Deguan Wang
Linked Author(s):
Keywords: GSTARS2.1; Degradation; Armoring; Tigris River
Abstract: The paper presents the applicability of GSTARS2.1 (Generalized Stream Tube Model for Alluvial River Simulation version 2.1) in the simulation of degradation and armoring problem in alluvial reach. GSTARS2.1 was developed by the U. S Bureau of reclamation to simulate and predict river morphological changes caused by natural and engineering events. The model uses a stream tube concept to compute the lateral variation in hydraulic and sediment transport conditions within the cross section, and it has the ability to deal with multiple flow regimes and to cover wide range of sediment transport conditions such as fractional transport, bed sorting, and armoring, non-equilibrium sediment transport, bank stability and channel width changes. The capability of the model to simulate degradation and armoring processes was tested using experimental data. The model was applied to a reach from the Tigris river to illustrate the degradation and armoring condition downstream of Mosul dam. It was found from calculated results that Tigris river in the studied zone may have reached armoring condition before closure of the dam. The existence of the dam reduces the availability of fine size fraction in the composition of the bed material. The depth of degradation in the river ranged between 0.5m near the dam to 0.1m at Mosul city.
Year: 2004