Sand excavations to begin at Narrabeen Lagoon Entrance

Northern Beaches

A major excavation of sand from near the entrance of Narrabeen Lagoon will begin on Tuesday as part of the ongoing management of the lagoon to reduce flooding risk. Repairs to the abutments of Ocean Street Bridge will be done simultaneously to minimise disruption to the community.

These major sand clearances are conducted every 3-4 years as swell and tides gradually push more and more sand into the lagoon. Council completed the last Narrabeen Lagoon entrance clearance in 2018 and has had to undertake more frequent mechanical openings in recent months as the sand has built up.

Works will be conducted using amphibious excavators to pump the excess sand through flexible pipes to a central stockpile location next to Birdwood carpark. From there it will be trucked down to Mactier Street where a bulldozer will spread it along Collaroy-Narrabeen beach.

Mayor Michael Regan said the works are an important part of managing the lagoon.

“It will reduce the risk of flooding to residents around Narrabeen Lagoon, replenish eroded areas further up the beach, as well as improve tidal exchange.

“Since we completed the last major excavations, waves and ocean swells have pushed sand back in and filled the entrance.

“Recent bathymetric surveys have revealed that tens of thousands of cubic metres of sand has returned to the entrance on the eastern and western sides of the Ocean Street bridge.

“Once the major excavation is complete, the lagoon is expected to remain open for a number of years, although as always, we are at the mercy of mother nature as to how long.

The lagoon clearance and bridge works will take around 12 weeks to complete (weather dependent) with the lagoon reopened in mid-December in time for the holiday period. During the works there may be minor traffic disruption in the vicinity of Ocean Street Bridge and some periodic limits to access to parts of the lagoon entrance.

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