Susceptibility and mitigation of debris floods and flows in the Jenolan Karst Conservation Reserve, NSW, Australia: Bushfire and La Niña impacts

This study assesses debris flood and flow susceptibility within the Jenolan Karst Conservation Reserve (JKCR), New South Wales, Australia, following the 2019 to 2020 summer bushfires and the prolonged 2020 to 2023 La Niña weather pattern. The bushfires significantly altered catchment hydrology by reducing vegetation cover and increasing sediment availability, while the subsequent extreme rainfall events triggered an increase in erosion and debris movement.

A detailed geological, geotechnical, and geomorphological assessment was conducted, incorporating the Melton Ratio to evaluate catchment susceptibility to debris floods and flows. The findings informed engineering solutions, including the design of debris barriers aimed at mitigating sediment transport and protecting downstream infrastructure. The study provides insights into the long-term impact of bushfires and extreme weather events on debris mobilisation, emphasising the importance of proactive mitigation strategies.