Water mains at risk: Major Hamilton intersection rebuild halted until solutions found

The roundabout at the intersection of State Highway 1C Cobham Drive and Cambridge Road will be replaced by traffic lights – once the underground water mains are protected or replaced. Photo / Waka Kotahi

Work to replace a roundabout with traffic lights at a busy Hillcrest intersection in Hamilton has run into an unexpected delay after it was discovered water mains 1.6 metres under the worksite were at risk of damage.

Waka Kotahi NZ Transport Agency is now asking drivers to avoid driving through the city’s State Highway 1C (SH1C) intersection at Cobham Drive and Cambridge Road if they can.

“Despite careful investigation during the design phase, including using ground-penetrating radar and examining all available records, it was not apparent that the water mains under the worksite were at risk of damage with the proposed works,” says Waka Kotahi regional manager for infrastructure delivery, Jo Wilton.

“We agreed with Hamilton City Council that we would temporarily stop work while we found solutions, to avoid this risk,” she says.

The agency is replacing the roundabout at the intersection of State Highway 1C (SH1C) Cobham Drive and Cambridge Road with traffic lights, including two signalised pedestrian crossings, on a raised intersection platform.

Work was carefully planned to begin in early January so that as much as possible could be done over the holiday period while there was less traffic and fewer people commuting or trying to get to school.

“Our aim was to return SH1C to two lanes in each direction by early February to minimise disruption, while the rest of the works were [to be] completed by around the end of June,” says Wilton.

Waka Kotahi and the city council are working closely to resolve the issue. Some of the original pipes can remain, protected with a concrete cap, and the remainder will be removed and replaced.

This means SH1C will remain one-lane-only in each direction for several more weeks, and there will also be some full closures from 7pm to 7am while water mains are relaid. The dates for these night-time closures will be shared as soon as they are confirmed.

All of this means the overall project timeframes have been pushed back around four to six weeks, with an anticipated finish now likely in August, weather-depending.

“It does mean significantly more disruption in the area, which will cause frustration,” Wilton says. “It will be particularly challenging for the parents and caregivers of children at Hillcrest Normal School during pick-up and drop-off times.”

Waka Kotahi is working with the school community and the Hamilton City Council’s school travel co-ordination team to find options and solutions, including alternative pick-up and drop-off points.

Waka Kotahi advises people to choose other routes and avoid the area if at all possible until the project is completed.

“People will be able to map out their best options using the Waka Kotahi Journey Planner,” says Wilton.

Waka Kotahi says the old roundabout was no longer fit for purpose due to increasing traffic volumes. The changes to the intersection, together with the completion of the Waikato Expressway and the Cobham Drive interchange, are the final pieces to allow the benefits of the Hamilton Ring Road to be fully realised.

Collectively, these improvement projects will reduce intra-regional traffic and the traffic that uses local Cambridge Road as a shortcut through Hillcrest, the agency says.

The Peacocks development project that is under way will contribute significantly to traffic growth at this intersection.

Waka Kotahi also reminds people that local Cambridge Road will remain left-in and left-out only while the work is under way. There is no longer an option to turn right from local Cambridge Road into Cobham Drive heading west; this is a permanent change.

Access to properties and businesses will be maintained at all times, and people are asked to follow the instructions of the traffic controllers when moving through the site, which has a speed restriction of 30 km/h.

Bus detours

Several bus routes that use the intersection will have short detours on their incoming (Hamilton-bound) journeys until the work is completed. These are the 10 Hillcrest, 17 Hamilton Gardens Uni, 20 Cambridge and 22 Eastern Connector services. For details on the diversion routes, visit https://www.busit.co.nz/hamilton-routes/.