Using dynamic risk profiles to create adaptation pathways for flood risk management

Floods pose a risk to societies all over the world. This risk is likely to increase due to a combination of drivers, including climate change, urbanization and changing demographics. Understanding how the future may unfold and what the key uncertainties are is critical in designing disaster risk management strategies, as we will only be able to reduce flood risk into the future if we account for these drivers. Accepting that we need to embrace uncertainty also means that we can no longer develop a single plan of risk reduction options that is effective for the coming decades and acceptable to all involved. Instead we need to explore approaches that can adapt to changing conditions and needs. Exploring these changes requires the ability to calculate dynamic risk profiles and assess the implications of risk reduction options impacting on these profiles. To support this, we have developed a spatially explicit and dynamic multi-hazard decision support system, UNHARMED, that calculates risk over time as a combination of hazard, exposure and vulnerability. Working with councils (working collectively as the Gawler River Floodplain Management Authority) and State Government agencies, we have downscaled a set of existing scenarios for South Australia to the Gawler river basin through a series of participatory exercises. Using UNHARMED, we assessed the implications of those scenarios on flood risk, and other metrics of interest to the stakeholders, along with the effectiveness of mitigation options under various scenarios. This information then helped to design adaptation pathways as a sequence of policy actions to achieve targets under changing external conditions – climatic and socio-economic. These pathways are in support of councils developing a collaborative strategic floodplain management plan accounting for urban development and flood risk, along with developing the business case for large structural flood mitigation works.