Central Coast Council will commence pro-active early flood mitigation works this month at The Entrance channel, establishing a pilot channel, in preparation for any significant weather events that may occur in the coming months.

The timing for the works’ commencement follows the end of the 2024-2025 Little Tern breeding season at Karagi Point sand pit, with the last birds departing the site in early February.  Any adults with their recently fledged chicks have now dispersed to quieter locations around Tuggerah Lakes and along the coast, before commencing their northerly migration in the coming months.

Council is pleased to report that despite the ongoing challenges posed by predators, especially avian predators and a range of human disturbances throughout the breeding season, Council’s best practice management actions have resulted in yet another season of record-breaking breeding success.

Council’s pro-active management works on establishing the pilot channel will now commence on 24 February, and will be similar to that created in 2024, which proved a key factor in minimising flood impact during heavy wet weather during autumn and winter.  While on-site, crews will also remove any temporary infrastructure that had been put in place during the Little Tern breeding season, such as fencing.

Council currently monitors the channel condition in real time (via remote cameras, satellite imagery and gauges, that monitor tidal range within the estuary) and forecasts catchment inflows and lake heights. This allows early intervention at The Entrance channel if a flood event is expected.

Council said the foreshores of Tuggerah Lakes, however, will always be flood prone, regardless of the channel configuration.

As was done in 2024, Council will establish the pilot channel, by excavating sand from the sand berm and to the north of the rock shelf as a pre-emptive action.

This is in accordance with Council’s procedures to reduce the time and effort required by Council work crews in the event of a flood and to ensure appropriate response actions are implemented faster for our community.

The main concerns with the current configuration of the channel are with its current tendency to track south between the rock shelf and The Entrance Beach groyne.

This is an observation Council has continued to see since construction of the groyne in 2017.  Prior to the construction of the groyne, even when constricted, the channel generally tended to flow to the north of the rock shelf.  With the channel tracking this far south, Council has seen continued erosion to the southern foreshore of the channel and impacts to infrastructure including beach access points and The Entrance channel Lifeguard tower.  In this configuration the channel’s capacity to naturally widen and scour during flood is limited.

Council understands the NSW Government, who constructed the groyne in late 2017, is currently reviewing the impacts of the groyne.  

Council expects to spend about three days on site establishing the pilot channel which will be approximately 10 metres wide and at a depth slightly above the current lake height, to the north of the rock shelf.

To slow infilling due to natural processes, such as tides and wave run-up, and extend its usefulness, the pilot channel will not be connected through to the ocean, leaving a sand plug in place at each end.  The sand plugs would be removed in a significant weather event, when the height of the lake compared to the ocean is sufficient to allow the pilot channel to successfully establish.

It is important to understand that unlike our other coastal lagoons, the Tuggerah Lakes are very low, almost at sea level, and if a connected pilot channel were to be ‘open’ to the ocean all the time, it would not flow but instead result in almost immediate infilling with sand from the ocean due to dominant coastal processes.

Further information is available at:  
https://www.centralcoast.nsw.gov.au/environment/coastlines/estuaries-lagoons-and-wetlands/tuggerah-lakes-estuary