Thursday, 12 May 2022

Residents on the Narrabeen Lagoon floodplain know too well the stress that comes every time there is forecast high rainfall, large swells or flood warnings.

Managing the entrance to Narrabeen Lagoon can help reduce the flood risk and we’ve been doing both large scale sand excavations and more regular mechanical openings to try to keep the entrance open when the flood risk is high.

As locals know, keeping the entrance open for long periods can be a challenge as current, tide and wave activity continually push sand into the entrance mouth eventually closing it to the ocean. 

So what is the most effective way to manage the flood risk? Should we continue to battle these natural forces and are there better ways to go about it than current practices?

This is the focus of the very comprehensive 300-page draft Narrabeen Lagoon Entrance Management Strategy currently open for community comment.

The draft Strategy is a broad investigation of all aspects of entrance management, including sand transport, flood behaviour and entrance efficiency and dynamics.

It considers a range of short, medium and long term options, from break walls to low flow pipes, mobile sand pumping and ongoing entrance clearance operations. 

Following the extensive assessment and analysis the draft Strategy recommends that we:

  • continue periodic large scale sand clearance operations
  • trial more frequent sand clearances but with smaller volumes, in targeted areas
  • continue intermittent mechanical breakouts if the lagoon entrance closes between major clearances and review trigger conditions, refine the location of any pilot channels and investigate improved technology for data collection
  • revegetate and maintain Birdwood Park dune to assist sand stabilisation
  • review mobile sand pumping (as an alternative to trucking) if lower cost pricing becomes available.

We’d love your feedback! You can dive into the full report or explore a chapter of interest. Or you can just get an overview by reading the 12-page snapshot document. View all options.

You can also register for the online information session, make a booking for a chat with the project team or register for a drop in session. We look forward to your input. Submissions close Sunday 19 June.

Learn more

Keep up with our News