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Published:
Jun 30, 2006Keywords:
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Main Article Content
Comparison of Two Different Transport Models to Predict Sediment Transport: Simiyu River, Tanzania, Case Stud
Abstract
This paper presents the results of a study which focused at the spatial and temporal characteristics of sediment transport and deposition in the main river channels and floodplains. Two different numerical models were used to simulate stream flow and to analyze sediment transport and deposition in the river channels: (1) the SMS modules RMA2 and SED2D and (2) the SCALDIS model developed at the Free University of Brussels. Both numerical models contain a two-dimensional hydrodynamic module and a sediment transport module, allowing simulation of stream flow and sediment transport processes in river channels. However, they differ in the following aspects: SMS based sediment transport is decoupled from the hydrodynamic module while SCALDIS is coupled model where the hydrodynamic and transport are run in real time. Both models were applied at the downstream section of the Simuyu River, which is located at the southeast of Lake Victoria. The models were independently calibrated with a typical flood year 1967/68 and then compared. Both model results indicate that the temporal variability of total sediment deposition during a flood event was strongly tied to the sediment inflow concentrations. The comparison of both model results indicates that SCALDIS is easier to calibrate as compared with SMS based sediment transport. The SMS modules require detailed information about a large number of model parameters, which are difficult to obtain in remote areas. The SCALDIS model is less input demanding, and the only sensitive parameter is the Manning's coefficient, which can be estimated based on expert  knowledge and limited field measurements.
