Climate change vulnerability assessment for ICOLLs and implications for strategic planning

The Wollongong LGA is located approximately 80km south of Sydney, NSW. There are a total of 14 estuaries located along the Wollongong coastline, all of which are classed at Intermittently Closed or Open Lakes and Lagoons (ICOLLs). Estuary Management Plans (EMPs) have been developed for all 14 ICOLLs in accordance with the NSW Government Rivers and Estuaries Policy. However, the EMPs were developed based on an understanding of how the estuaries function under current climatic conditions. Wollongong City Council is seeking to apply the best available climate change predictions for the Illawarra Region in order to: - Assess the vulnerability of these 14 estuaries to climate change impacts and consider how their character will change in the future; and - Consider the implications for ongoing estuary management. The assessment technique primarily focussed on the likely impacts of climate change on estuarine biodiversity, based on an assessment of the predicted changes in catchment inflows, geomorphology, water quality and entrance behaviour for four planning horizons: 2030, 2050, 2070 and 2100. The methodology used a combination of quantitative and qualitative techniques to characterise the likely changes in estuarine physical processes and form, including topographical analysis using LiDAR data and evaluation of coastal processes affecting berm behaviour. Impacts on biodiversity were assessed using biodiversity benchmarking and consideration of species-specific environmental tolerances. The assessment raised a number of questions relating to strategic planning for coastal environments under climate change conditions: - How might current flood mitigation practices for ICOLLs need to be modified in the future? - What are the likely interactions between existing pressures on estuaries and those resulting from climate change? - What are the key obstacles to incorporating adaptive measures into estuary management? This paper will present the findings of the climate change assessment for Wollongong's estuaries and provide a discussion of these findings in the context of ongoing management and strategic planning.