Source: New Zealand Transport Agency
Waka Kotahi NZ Transport Agency has awarded a $3 million contract for work to manage coastal erosion affecting State Highway 1 alongside Katiki Beach, North Otago. The contract has been awarded to Downer NZ.
The beach is north of Palmerston and Shag Point, south of Moeraki and Hampden.
Around 7km of highway in this area is located between the main trunk rail line and the Pacific Ocean. Coastal erosion is occurring along the length of Katiki Beach, says Waka Kotahi Senior Project Manager Jason Forbes.
“Erosion protection structures were constructed in the 1970s where the highway was threatened with erosion then. The highway’s proximity to the railway line makes realigning the road a very expensive option, with rock armouring of the beach a more viable alternative.
“The contract will enable the coastal erosion protection work completed in 2017 to continue. This will involve rock armouring sites between the intersections of SH1/ Shag Point Road and 300m south of the SH1/ Squire Road intersection.”
Rock armouring involves placing rocks alongside the shore to stop the sand being taken away and protecting the highway from erosion.
“In 2017, three high risk sites were rock armoured to stop coastal erosion from undermining the highway. This new contract is to complete a further 10 sites identified as a high priority for protection work,” says Mr Forbes. “Erosion along this coastline has been monitored annually since 1994, identifying the sites needing protection work. Most of Katiki Beach will eventually require some rock armouring, so coastal erosion doesn’t damage SH1, a critical road freight and Lifeline link between Dunedin and Christchurch.”
Subject to weather and consenting requirements, work will get underway in early 2021 with the stockpiling of rock onsite. All the work associated with this contract should be completed within a year, he estimates.
An example of the problem at Katiki Beach.
Photo of the start of rock armouring.
An example of existing rock armouring at Katiki Beach.
More information can be found in the background report by Stantec(external link)
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