Fire frequency curves used to predict water yield

A researcher from RMIT University has correlated the severity and frequency of bushfires in order to predict water yield in related natural water supply catchments. Dr Anirban Khastagir, of the School of Civil, Environmental and Chemical Engineering, devised unique fire frequency curves as part of his PhD research.

A methodology has been developed to use these fire frequency curves to determine the potential reduction in water yield in any given year for the Victorian catchment. This will assist water infrastructure planning and help water authorities to predict the impact of the increasingly frequent fires, which may be resulting from climate change.

Different locations of Victoria were regionalised into homogenous areas, based on the Forest Fire Danger Index, to develop the fire frequency curves. Dr Khastagir said the curves could augment the information used by the Country Fire Authority, Victoria, to determine the risk or probability of the occurrence of bushfire events for any location in Victoria.

“Bushfires in water supply catchments can adversely impact the reliability of water supply, thus threatening the wellbeing and prosperity of industry and the community supplied from these catchments,” he said.

A set of water yield curves was developed by relating the reduction in water yield with the probability of percentage of area burnt for a 1-in-20-year fire event.

“Results from these applications will assist catchment management and water supply authorities to determine the maximum reduction in water yield from affected catchments due to the predicted fire event,” Dr Khastagir concluded.