Stormwater Catchment Modelling, Planning and Design for Gatton

WMS, in conjunction with RMA Engineers, were commissioned by Lockyer Valley Regional Council to undertake stormwater catchment modelling, planning and design for the township of Gatton. Some areas of the town are subject to flash flooding, even during relatively minor events.

An unconventional modelling approach was adopted for this study to allow a significant number of mitigation options and iterations within a short time frame. Existing scenario TUFLOW models confirmed the complex overland flood flow within the catchments and that the existing infrastructure is undersized and is at capacity during minor flood events. Existing and mitigated scenario DRAINS models were developed to undertake a significant number of design options/iterations within a relatively short time frame. A wide range of mitigation options were investigated, sized and iterated for the hot spot areas. A high-level MCA identified which options were most viable to address the flood hot spot areas based on a quantitative assessment of options. The preferred option for each hot spot area was finalised and input into the developed scenario TUFLOW models.  From the mitigation options, a prioritisation schedule was developed which included a commentary on staging of works.

Lockyer Valley Regional Council inherited the prioritisation schedule, concept designs and suggested improvements to existing detention basins, ready to take to the next phase detailed design, financing and construction.