One of the advantages of using HEC-RAS for a sediment transport simulation is that many systems have existing, fixed bed, HEC-RAS hydraulic models. Because the sediment transport model uses the same geometry file, building the sediment file from an existing sediment model includes some efficiencies. However, sediment models require special attention to certain aspects of the 1D hydraulics.  There are some cases where the sediment model will be more sensitive to 1D hydraulic assumptions than a standard hydraulic analysis, and other cases where users might want to set up a 1D sediment model a little differently than they would if it was just a fixed-bed hydraulic model. 

This section covers some of the issues sediment users should consider as they set up their hydraulic model, before they even open the sediment data editor.