The study area comprises a number of catchments in the north of the Pittwater LGA, from Bilgola Beach in the south to Palm Beach in the north. This area includes the Avalon town centre and Careel Creek which have experienced flooding historically. Pittwater Council has been managing flood risks within the study area over many years. Among other measures, a detention basin has been built in Avalon Golf Course, culverts to convey Careel Creek flows under Barrenjoey Road at North Avalon have been built and Council’s DCP ensures that proposed developments in the floodplain consider flood risk. The principal outcomes of this study include:
- A consolidated Flood Study (Chapter 7), with estimates of flood extents, levels, depths and velocities for the 20% Annual Exceedance Probability (AEP), 5% AEP, 1% AEP, 0.5% AEP, 0.2% AEP and PMF events;
- Mapping of the high, medium and low Flood Risk Precincts and of Flood Life Hazard categories (Chapter 7);
- Definition of the flood problem by construction of a property database and assessment of building inundation, road inundation, evacuation ‘hot spots’ and flood damages (Chapter 8);
- Further definition of the flood problem by a formal risk assessment; this shows that catastrophic damage to houses is largely confined to very rare events (medium risk) but moderate damage is expected in frequent events (high risk); areas of pronounced risk in the study area include Pittwater Palms retirement village, the Avalon town centre and the Elaine Avenue precinct (Chapter 9);
- An assessment of potential floodplain management measures (Chapter 10) and detailed evaluation of flood modification options (Chapter 11), property modification options (Chapter 12) and response modification options (Chapter 13);
- An assessment of the potential impacts of climate change (Chapter 14);
- A recommended Floodplain Risk Management Plan (FRMP) for the Avalon to Palm Beach study area (Chapter 15).
