Onehunga lagoon dredging project on the table

Following recent flooding events on Beachcroft Avenue (3 in the last 8 months), the Onehunga Enhancement Society TOES have suggested to the Maungakiekie Tamaki Local Board that they look into the possibility of dredging the Onehunga lagoon.

Auckland Council

According to TOES, funding needs to be sought for dredging the Onehunga lagoon, improving the drainage from Beachcroft avenue to the lagoon and upgrading the lagoon tidal gates.

“Dredging will provide for greater resilience during heavy rain events as the lagoon can take up more water running off the land,” said TOES in the release. “Upgrading the tidal gates to automate them to respond to forecasted heavy rain events and overflow is essential. The gates should automatically empty the lagoon prior to heavy rain events and then lock the gates so that the tide cannot re-enter.”

Coupled with a deeper lagoon from dredging, this will allow the lagoon to take the maximum amount of rain possible.

The Onehunga lagoon in Auckland, New Zealand, was created in the 1970s as part of the State Highway 20 development. Since then, it has never been dredged and the lagoon has silted up reducing its capability for storm water catchment and degrading the lagoon as a recreational asset.

A greater depth of water will also help alleviate algal bloom created by heating of a shallow depth of water.