Marks Point is a low lying area that experiences frequent tidal inundation from Lake Macquarie. Local tidal inundation is projected to increase as sea levels rise due to climate change. As part of the Marks Point and Belmont South Local Adaptation Plan, the community proposed to address this risk by using tidal flaps (or valves) on stormwater outlets to prevent the ingress of lake water into the stormwater system. Lake Macquarie City Council installed tidal flaps on two stormwater outlets to trial their effectiveness under local conditions. The community monitored the performance of the flaps during high tides and rainfall events. While the flaps were successful at preventing lake inundation during high tides, they caused the stormwater system to backup during rainfall events resulting in localised flooding. The trial has identified further design considerations including head pressure within the stormwater system.
Check it out here:
https://lgnsw.org.au/common/Uploaded%20files/Environment/BRCC%20Case%20Studies/7.%20Lake_Macquarie_TidalValves.pdf