A one dimensional sediment routing model for steep torrent channel networks called SETRAC has been developed at University of Natural Resources and Applied Life Sciences, Vienna. SETRAC is the acronym for Sediment Transport Model in Alpine Catchments. Different sediment transport formulas and flow resistance approaches can be selected in SETRAC for steep channel slopes. To take form roughness losses into account several approaches are available to modify the calculated transport capacity to better match observations on bedload transport. Armouring effects can also be considered. In addition it is possible to calculate fractional bedload transport and considering grain sorting effects in combination with mobile bed conditions. In SETRAC the channel network is represented by nodes, cross-section and sections. The sediment is transferred through the channel network considering sediment budget in sections. Initial erosion depth can be assigned for each channel reach. Morphologic changes due to erosion and deposition are calculated.


Figure 1: Cross-section with visualisation of the specific bedload transport 

 A graphical user interface with visualizations of the longitudinal sections as well as the cross-sections has been developed. For calculation the cross-section is divided into strips to get a representative discretization of the profile. The number of strips depends on the number of points that are used to specify a cross-section, implying that the number of strips increases with the complexity of the cross-section (see Figure 1). Flow hydrographs are routed as kinematic wave through the channel system. Sediment input as sedi-graphs is also possible. All simulation results can be stored as longitudinal profiles as well as time series for all cross-sections in user defined time intervals as text files for further analysis. The last time step with information about the highest values can also be exported as DXF file for plotting the results for engineering applications.

The development of the actual version of SETRAC has been funded by the Austrian Science Fund (FWF) through the Translational Research Program L147 on “Sediment routing model for steep torrent channels”.