Kyogle - Flood Mapping Study - Technical Addendum

During the course of the Flood Mapping Study, results predicted by the model appeared at times to be inconsistent with expected behaviour: In particular, the HEC-2 model appeared to incorrectly estimate the equivalent Manning's 'n' value or equivalent conveyance of a main channel section consisting of composite zones of hydraulic roughness. This led to a review of various methods for estimating equivalent 'n' values which is reported in this Technical Addendum