DCC pioneering new method to combat coastal erosion

Tom Dyer.
Tom Dyer.
The Dunedin City Council is pioneering a new method in its efforts to stop coastal erosion on Dunedin beaches.

A series of notches will be cut along the sand dunes below John Wilson Ocean Dr to encourage natural growth of the dunes and reduce the impact of erosion.

Dozens of notches will be cut at 10m to 15m intervals between the St Kilda Surf Life Saving Club and Lawyers Head.

The notches will be 1.5m-2m wide and 1m-2m deep.

Council 3 waters group manager Tom Dyer said the notches were a simple way of building up the back of the dunes by making it easier for the wind to shift the sand to where the council wanted it to go.

They were designed so the wind would blow sand to the back of the dunes in strong west to southwest winds, and allow the dunes to grow over time, Mr Dyer said.

Work was initially expected to start this week, but forecast stormy weather meant it was postponed until next week.

Overall the work would cost about $4000.

As part of the process, vegetation would start to grow on the new sand and the dunes should become more resilient to erosion caused by storms and rising seas, he said.

People would be able to walk through some of the notches for easier access to the beach and the less accessible notches could provide spaces for New Zealand sea lions to rest.

A trial of the process in 2016 successfully built up dunes and a monitoring programme is being developed by the council and the University of Otago.

Associate Prof Mike Hilton, from the university's department of geography, said it was the first time internationally a local authority had managed a foredune this way, which not only protected coastal assets from storms but also improved public access to the coast.

''This is an exciting development for the coastal scientific community and the people of South Dunedin, and the results of the work will be closely followed,'' Prof Hilton said.

tim.miller@odt.co.nz

 

Comments

I honestly hope it works Tom, the cost appears good value. Does it include the fences and signage to advise beach walkers?