Good things come in threes with the third in a trio of culvert replacements and upgrades to cater for higher flood waters on its way for a Central Otago community.

A four-metre-square culvert is about to be replaced by one nearly four times bigger to improve road flooding resilience in Roxburgh, says Waka Kotahi NZ Transport Agency.

Measuring five metres by three metres, it will be installed at Black Jack’s Creek on State Highway 8 in a month’s time.

24/7 road closure for eight days early October

Removing the old undersized culvert and installing the big, new one will mean a full highway closure for eight days, 24/7, from Sunday, 1 October at 8 am to Monday, 9 October, 8 am.

“It is important freight users know if their vehicles can use the posted detour route,” says Michael Tannock, Network and Structures Manager for Waka Kotahi in Otago and Southland. “And we appreciate everyone’s care around our crews and on the detour route, which will add 20 or 25 minutes for people at either end of the highway closure.”

• Black Jack’s Creek/culvert is about 2.2km south of Golf Course Creek.
• Golf Course Creek’s culvert was upgraded with increased capacity in October 2022.
• Pumphouse Creek culvert was replaced in 2021.

“All three creeks had an ongoing risk of flooding,” says Michael Tannock. “The larger culverts will help channel flood waters and gravels under the road down to the Clutha River/Mata-Au.”

SH8 will be fully closed road from Jedburgh St to Millers Flat Bridge Road.

Residents and business owners will have access inside the closure points and up to each side of the work site, but due to the nature of the works no traffic including pedestrians or cyclists will have access through the work site.

All of the work is weather dependent, so dates could alter if it is wet.

The detour

For the eight days of work the detour route will direct northbound highway traffic on SH8 onto Millers Flat Bridge Road across the Clutha River/Mata-Au, onto Teviot Road for 17km, onto Jedburgh St and back onto SH8 (reverse for southbound traffic). Temporary speed restrictions will apply along this route. An electronic sign board will be in place to remind drivers.

Freight route detour

While High Productivity Motor Vehicles (HPMV) Higher Mass Permit and 50MAX truck trailers can take the detour route, overweight vehicles and over-dimension loads will not be able to. For all OD load enquiries please contact Central Otago District Council directly.

Background

This programme was developed after several flooding incidents in recent years. Waka Kotahi has engaged with local residents and businesses about the plans and are looking to limit disruption where possible.

The overarching goal for these projects is to improve the resilience along this section of SH8 and maintain and protect the infrastructure of the township of Roxburgh.

The works are being carried out on behalf of Waka Kotahi by roading contractor Aspiring Highways. Waka Kotahi has been working with the Otago Regional Council which completed a catchment study of the area, leading into the expanded culvert programme.

Background study on the catchment:

• Research study of Roxburgh catchment and history of flooding: https://www.nzgs.org/libraries/managing-ongoing-debris-flow-risk-in-roxburgh-otago/

Local information

If there are concerns or questions around these works, road users can contact the Aspiring Highways team at customer@aspiringhighways.co.nz or call 0800 4 HIGHWAYS (0800 44 44 49).

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