Yes. The road across the dam will be closed for 24-36 months so we can safely work on the left abutment. We will have a team of contractors and equipment moving around the work site, so keeping everyone safe is paramount. We aim to work during the day and then possibly at night so we can get the job done quickly and reopen the road as soon as we can.

Powerhouse Road was successfully used during earlier works in 2005, but the new project is longer and must meet higher modern safety standards. We are working on upgrades so it can be safely used as a detour route during the multi-year timeframe of the project.

The purpose of the detour is to continue to let local communities connect for work purposes, to attend schools, for people who have farms and need to use small vehicles to travel to properties on either side of the dam.

No. Engineering assessments confirmed that Powerhouse Road cannot safely accommodate High Productivity Motor Vehicles or long heavy units, oversized vehicles, and extended freight trucks over a sustained period. Restrictions are required due to the route’s physical constraints, narrow shoulders, tight geometry, gradients, and a one ‑lane traffic‑light‑controlled section that makes it unsafe for HPMVs and long units.

Cars, light vehicles, motorcycles, school buses, emergency services, rigid trucks up to 8m.

HPMVs and large freight will need to use the State Highway network (SH1/SH21/SH3 via Tamahere) if they wish to travel from east to west and vice versa without going through Arapuni.

No. The detour is not safe for walkers or cyclists to use with vehicle traffic. We’re working with Waikato River Trails to make sure users are aware of the closure.

If more cyclists arrive expecting to cross the dam or use the detour, we’ll step up communications and look at other ways to share this information. In situations where it’s necessary and feasible, we may use our site vehicles to transport bicycles using bike racks. However, this is not intended to become a regular solution, as we are not providing a shuttle service.

No. To keep everyone safe, we will close the western end of the swing bridge where it connects to Powerhouse Road. Pedestrians and cyclists won’t be able to use the walking trails near Powerhouse Road, but the Waikato River Trail will remain open and available for people to use on the village side of the river. 

Engineering advice suggests keeping this open is an unacceptable risk to public safety, previously in the mid-2000s we experienced vehicles stopping in the single lane section with the swing bridge was open that caused significant operational and safety impacts to the detour.

Yes. The cafe will continue operating as usual, and any changes to their hours will be made solely at their discretion and communicated through their own channels. 

To support visibility throughout the detour period, we have worked with the cafe to create roadside signage clearly signaling that the cafe remains open. These signs will be installed shortly before the detour becomes operational to ensure road users know the cafe is still open.

There will be limited opportunities for parking and to fish from the headrace bridge. 

All other locations, such as tailrace bridge and dam, will be restricted during construction with the detour in place, as these areas will be closed for safety. Clear signage will be installed to indicate restricted access, and our on‑site team will be available to provide guidance if needed. Sightseeing around the dam will also be affected, particularly for those who usually walk through the dam area or use the car park. These areas will be cordoned off for construction activity and access changes. We will communicate any restrictions or updates early and clearly so people are aware.  

Yes. We know fuel prices are high and that detours add time and cost. This detour has been designed to minimise delays (around 10–12 minutes), and we encourage people to plan ahead using tools like the NZTA Journey Planner and council and NZTA updates to find suitable routes. While fuel prices are outside the project’s control and increased after traffic planning was completed, the detour is essential to deliver this work safely and without significantly extending the project. We will continue to provide timely updates so people can plan their travel and move safely and efficiently.

We plan to hold our fourth event on 11 April 2026 and will plan to meet again with the community later in 2026, once the main works programme begins operating.

While there will be no change to the electricity generation, doing the required works now ensures that future generations can continue to benefit from this integral hydro asset. The power station will continue to operate as normally during the work.

We will continue to engage with stakeholders and local community to let them know what is planned. If you would like to contact the project team, please email: project.arapuni@mercury.co.nz.