New streamlined HEC-RAS importing

CHI has introduced an advanced easy-to-use tool for importing river models from HEC-RAS (version 4.0 and earlier) into PCSWMM for modeling with the EPA SWMM5 dynamic wave, kinematic wave or steady-state routing methods. Simply select the geometric file you wish to import, and PCSWMM automatically imports the reaches, cross-sections, bridges and culverts. New bridge/culvert importing options allow for the automatic representation of iregular high chords, low chords, multiple piers, and entrance/exit losses. System connectivity, cross-section roughness, elevations and original georeferencing are all preserved.

The imported model is immediately ready to run in PCSWMM using the EPA SWMM5 engine. Multiple HEC-RAS models (i.e. for different reachs) can merged in PCSWMM and the resulting imported model(s) can be reprojected to any coordinate system with the PCSWMM reprojection tool. Hydraulic system inflow can be directly entered or computed from the SWMM5 hydrologic rainfall-runoff relationship. Flood inundation polygons can be generated (and animated) from the SWMM5 results and the model layers rendered in Google Earth (including animations) for client presentations.

The approach taken by the tool for setting up HEC-RAS river systems for simulation with the EPA SWMM5’s dynamic wave routing method has been refined so that junctions depths compare well with the original HEC-RAS steady state mode throughout the system (including at bridges/culverts). Optionally, settings in the import tool allow for ensuring the imported model is compatible with EPA SWMM5 kinematic wave routing.

Available in PCSWMM 2009 version 3.5 (released Dec 24, 2009).