As Australia battles wild weather and coastal erosion, we should learn from our mistakes | Wendy Harmer

The story of King Cnut the Great (Canute to you) is often misunderstood.

Not only is it arguably the ugliest edifice ever built on the Australian coast, but when vertical walls are built on narrow beaches they reflect and concentrate wave energy, accelerating erosion rather than ameliorating it.

This section of beach is now facing extinction.

Gordon, who has been recognised by the United Nations as an international expert on coastal zone management, has been involved with projects worldwide. And, as a former manager of Pittwater council (now amalgamated with Northern Beaches), he knows the problem of beach erosion first-hand.

In the past (under the previous 1979 Act), a development like the Collaroy seawall would have come before an independent state government Coastal Panel. In fact, a seawall of almost the same vertical design now being built on Collaroy-Narrabeen beach was panned by that (now abolished) expert panel.

Those solutions include rock revetment walls, sand nourishment and strategic buyback of threatened properties.

In 2019 the NSW government appointed an independent building commissioner after a series of catastrophic failures in that sector.

The resulting DA only attracted mere handful of written submissions. Despite decades of community activism to protect the beach, so many were blindsided by the development. Where was the community forum? The input from surfers, beach lovers and residents in the wider community. We must have missed it.

The council is now pushing to extend the seawall further north along the beach.

Many locals are calling for a moratorium until the Northern Beaches council has taken independent, expert advice and declared its reasoning and intentions beyond a few private landowners.

When the preservation of a precious beach for future generations is at stake, we all should have a say.

The ancient king had it right. When it comes to protecting our beaches, old Cnuts often know best.