Update: Narrabeen Lagoon entrance

Given the forecast rain in the coming days and a water level of 1.1m, Council today used the channel created last week and opened the lagoon to the ocean.

The conditions are not as ideal as we would like for an opening and the lagoon entrance may close again over night. However, we will be closely monitoring the situation and have crews and machinery on standby to reopen the entrance if needed.

To understand the natural forces that we have to balance in a lagoon opening, please watch the video explainer.

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Friday 2 July

Council has excavated a preparatory channel at Narrabeen Lagoon and is closely monitoring conditions, after recent large ocean swells again closed the entrance and raised the water level in the Lagoon.

While the Lagoon water level is high, it is below the level where an entrance opening is likely to be successful without further rainfall.

Managing the entrance to Narrabeen Lagoon is a complex operation. Council regularly uses heavy machinery to open the lagoon to the ocean when there is the right combination of rainfall, lagoon levels, and ocean conditions.

Opening it at the wrong time can mean it can close back up quite quickly and even cause additional sand build up, making it more difficult to open the next time.

Minimal rainfall is forecast for next week, however, a channel has been cleared and Council staff are monitoring lagoon water levels and rainfall forecasts, and machinery and crews are on standby should conditions change.

The large volume of sand throughout the entrance is contributing to how often the entrance is closing, and Council is also completing the preparations for the next large-scale sand clearance planned in the coming months.

Here is a video on Council’s management of the Narrabeen Lagoon.