Abstract
For a Rancho Cielito Dam breach, the HEC-RAS and DSS-WISE Lite “equivalent” models produce similar results for inundation boundaries, maximum depths, and maximum velocities throughout the inundation extent, regardless of their differing basis equations and computational methods. However, several potentially flow-altering terrain features were not captured in the terrain file, which cannot be modified in DSS-WISE Lite by the user except to remove bridges. These features included freeway sound walls, culverts, and levees, which, when included in HECRAS, had a pronounced effect on the inundation boundary and flow characteristics. While DSS-WISE Lite’s setup is significantly simplified, runtime is incredibly fast, and accuracy appears comparable to that of HEC-RAS, thus making it the model of choice for many dam breach scenarios, the lack of ability to make terrain modifications must be taken into account by the modeler. For areas where significant terrain features are not captured in the terrain data, HEC-RAS offers the modeler a wide variety of options to mitigate this issue.