News | 27 October 2016

Work under way on south coast seawall

One of Wellington’s oldest seawalls is being significantly upgraded to help protect a part of the south coast that has been repeatedly damaged by high seas.

This image taken in winter 2013 shows high seas surging over the road near the Victoria University Coastal Ecology Lab on Wellington's south coast between Island Bay and Owhiro Bay.
Waves surge across the road on Wellington's south coast during a big storm

The work getting under way, between Island Bay and Owhiro Bay opposite the Victoria University Coastal Ecology Lab and The Bach café, involves strengthening the existing wall and installing new pre-cast concrete panels on top to make it higher.

From the road, the wall will be about a metre high and look similar to the Island Bay seawall.

Work has also started at Lyall Bay to protect the road and footpath there and reinstate the sand dunes. This will include filling the gaps in the existing concrete block wall behind the dune and replacing the old rusted metal fence. More coastal protection work is planned at Dorrie Leslie Park early next year.

Wellington Mayor Justin Lester says the projects are the latest in an ongoing programme of infrastructural improvements designed to help protect vulnerable parts of Wellington from severe southerly storms.

“The intensity and number of storms affecting Wellington’s south coast have risen in recent years and the reality is that these parts of the city will be under increasing pressure,” he says.

“The Council is working on a number of fronts to help make the city more resilient to climate change, bigger storms and sea-level rise and improved seawalls are a part of the mix.”

The road and footpath near the Coastal Ecology Lab was one of the areas badly damaged during a major storm in June 2013, resulting in road closures and traffic disruption. The area was repaired but damaged again in August 2014 and again last year.

The original wall, which was built early last century and is about a metre lower than the road, will be repaired, upgraded and securely anchored to the rock below with a series of long steel rods.

More than 40 pre-cast concrete panels will then be trucked to the coast two at a time from mid-November. A crane is required to lift the heavy panels into position and traffic will be down to one lane for short periods while this happens.

Once that’s done, earth will be brought in to create a 3-metre wide area next to the wall that will be landscaped with hardy native plants. A concrete footpath going in next to the road will be double the width of the existing asphalt one.

The project will include building two new sets of stairs.  

“These will provide easy access for students, researchers, divers and other people wanting to get down to the foreshore, rock pools and sea in this part of Taputeranga Marine Reserve,” Mayor Lester says.

Work in the area is expected to be complete by the end of January 2017.

Since the big storm in 2013, Wellington City Council has carried out about $4 million worth of major protection work at Shelly, Princess, Karaka, Island and Breaker bays, plus numerous smaller road and seawall repairs around the harbour and south coast. The work has been partly funded by the NZ Transport Agency and insurance.