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coastal inundation
The Manning River Floodplain Risk Management Study and Plan 2019 is Council’s primary planning instrument covering flood, coastal inundation and tidal inundation in the Manning River ECMP Planning Area. Coastal Management Programs prepared under the Coastal Management Act are not intended to take precedence over other council plans, but rather to provide information to support the more effective consideration of coastal hazards and estuary health in other statutory and operational plans. Objects of the Coastal Management Act 2016 relating to flood, coastal inundation and tidal inundation in our Planning Area include: a) to facilitate ecologically sustainable development in the coastal zone and promote sustainable land use planning decision-making b) to mitigate current and future risks from coastal hazards, taking into account the effects of climate change c) to recognise that the local and regional scale effects of coastal processes, and the inherently ambulatory and dynamic nature of the shoreline, may result in the loss of coastal land to the sea (including estuaries and other arms of the sea), and to manage coastal use and development accordingly d) to encourage and promote plans and strategies to improve the resilience of coastal assets to the impacts of an uncertain climate future including impacts of extreme storm events. Under the State Environmental Planning Policy, Coastal Vulnerability Areas are defined as land subject to current and future coastal hazards. There are seven types of coastal hazard defined by the CM Act. Within the Planning Area for the Manning River ECMP, the potential hazards could include: • coastal inundation • tidal inundation • erosion and inundation of foreshores caused by tidal waters and the action of waves, including the interaction of those waters with catchment floodwaters.
6.10.1 Flood
There is a long and relatively frequent history of flooding within the lower Manning River. The four largest floods on record occurred in 1866 (peak flood level: 5.15 m AHD), 1929 (peak flood level: 5.9 m), 1978 (peak level: 5.75 m) and March 2021 (peak level 5.65 m) (Figure 33).
