HydroCAD Dam Breach vs. HEC-HMS Dam Breach

[Weimsguy]

I am working on a Dam Breach analysis for a small dam in Southlake TX. "The Hydrologic and Hydraulic Guidelines for Dams in Texas" by Texas Commission on Environmental Quality (TCEQ) states in section 8.4 Dam-Breach Models "For existing small or intermediate size dams, regardless of hazard rating, a simpler (but less accurate) hydrologic model, such as HEC-1 (HMS), is acceptable for modeling the breach flood wave and to determine inundation limits.". I have not used the HEC-HMS Dam Breach, but had been studying HydroCAD and thought that its treatment of the Dam Breach was similar, if not better than, the HEC-HMS model. Does anyone else have an opinion about the equivalence of the two approaches?

If the owner of the Dam wants to submit a breach analysis to justify a reduction from a high hazard classification, the dynamic wave model in HEC-RAS, DAMBRK, or FLDWAV should be used.