The Challenge

In 2014, Toowoomba Regional Council successfully completed 42 flood studies for 35 locations. For ten townships, both riverine and overland flows were modelled and mapped. For each location, the overland flow component had been separated from the riverine component, however substantial variation between the severity of overland flow existed. The purpose of this project was to separate the overland flow areas into two categories based on severity to assist with decision making and implementation to the Planning Scheme update.

Approach and Outcomes

WMS developed separation criteria based on depth and depth velocity product to separate flooding arising from overland flow into the two categories. The overland flowpath separation was undertkaen for each township using ArcGIS. The results were subsequently manually edited to develop polygons suitable for implementation to the Planning Scheme update. A  statistical analysis was also undertaken to inform Council of the magnitude of the areas of potential concern.