Water Technology have stormwater and riverine flood studies for six towns in the Western Downs Regional Council (WDRC) area using MikeFLOOD to assist with the revision of their planning scheme following recent council amalgamations. Water Technology has also provided expert advice to WDRC with respect to inclusion of the modelling results in the scheme. Stormwater and riverine flooding studies have been undertaken for Chinchilla, Miles, Wandoan, Tara and Jandowae. In addition, for Dalby we have undertaken a stormwater study and assessing the effect of recent development on flooding through modification of the existing riverine flood model (developed by others). The riverine flood study identified areas at risk of inundation and their impact on current and future development. The stormwater analysis defined and mapped stormwater corridors, and defined trunk drainage infrastructure needed for development.
Interesting challenges that were faced during the project include: determining representative observed rainfall and runoff data, regionalisation of flood frequency analyses, regionalisation of model parameters, application of areal reduction factors to rainfall estimates on large catchments, stormwater flow path identification in (very) flat terrain and identification and documentation of structures (e.g. illegal bunds).