Author(s): L. J. Pearce
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Keywords: Small catchments; Dams; Design floods; Regional floods; Seasonality; RORB
Abstract: The Water Corporation is custodian to more than 30 dams with small catchments (less than 100km2) in the south west region of WA. Despite these small watersheds, dam safety guidelines require spillways capable of passing large to extreme floods. Most sites are ungauged and early flood estimates were based on regional results extrapolated down from modelled larger dam catchments. In this study, a representative range of small gauged catchments were assessed ranging between 0.8km2 and 82 km2 and varying in rainfall zone and clearing. Seasonal flood frequency analyses were performed along with catchment modelling (RORB). This enabled the derivation of regional equations for large to extreme seasonal flood estimates and RORB modelling parameters, with variations for clearing, rainfall zone and possible inundated or other impervious surfaces.
Year: 2011