A spatial framework for regional-scale flooding risk assessment

The mining sector in Australia and globally has always been vulnerable to extreme weather with excess water due to flooding and deficient water through drought. Estimating flood inundation risk at a regional scale is essential for understanding sustainable mine water management, such as the Bowen Basin in Queensland, Australia. In this region, many coal mines have been facing a major challenge of increasing risk of flooding caused by intensive rainfall events. This research develops a spatial multi-criteria decision making (SMCDM) framework to assess flooding risk at regional scale using part of the Bowen Basin as a case study. Spatial data, including climate, hydrology, topography, vegetation and soils, were collected and processed in ArcGIS. Several indices were generated based on long-term observations and modelling analysis taking account of average recurrence interval (ARI) of rainfall and stream flow, potential soil water retention, elevation and slope extracted from DEM, drainage density and proximity derived from river network. These spatial indices were weighted using the analytical hierarchy process (AHP) method. The weighted criteria were integrated in the risk evaluation model. A regional flooding risk map was delineated and verified using the inundation extent corresponding to the maximum ARI detectable by MODIS imagery in the region. The result provides baseline information to help Bowen Basin coal mines identify and assess flooding risk when making adaptation strategies and implementing mitigation measures in the future. The framework and methodology applied in this study is expected to offer an effective approach in managing flooding risk and uncertainty in water availability under climate change for the Australian mining industry.