About this project
The Kopu Bridge Replacement project affected a 6km section of SH25 from the Hauraki Road intersection located west of the existing bridge, to the intersection on the eastern side of the bridge.
The old bridge crossing the Waihou River was built in 1927/28 and had only one traffic lane. It is 465m long and features a swing span to allow passage for large boats. Road traffic was controlled by traffic signals at each end. An average 9000 vehicles used this section of SH25 each day, but during holiday peaks this number can more than double. The one lane bridge was a traffic bottleneck, particularly during holiday peaks.
The Kopu Bridge Replacement project included a new 580m-long, two-lane bridge over the Waihou River, a new four-leg, two-lane roundabout at the junction of SH25 and SH26, and 2.5km of associated approach roads, including a new link road to SH26 east of the bridge. The bridge and approaches have a design speed of 100km/h.
The new bridge is 12.95m wide with 3.5m wide traffic lanes, 1.2m shoulders and a combined pedestrian/cycle lane on the north side of the bridge. This pedestrian/cycle lane is separated from the traffic lanes by a concrete barrier.
The bridge and embankment design will not adversely affect flood levels. The project has been designed to accommodate 100-year floods.
The NZTA is also investigating options for replacing the nearby Kirikiri Stream Bridge on SH26. This bridge restricts flood flows and can cause flooding of the highway and surrounding land. A replacement bridge with greater waterway capacity would also alleviate a flooding problem which impacts on land around the Kopu Bridge project. The Kirikiri Stream Bridge replacement project also includes improvements to the SH26/SH25A intersection (Kopu-Hikuai). This work is currently in the investigation stage, with Beca Consultants engaged by NZTA to look at various options.
What this project includes
The Kopu Bridge replacement project includes:
- A new two-lane bridge, 580m long, with a cycle/walkway.
- 2.5km of new approach roads, including a new link road to SH26 east of the bridge.
- A new four-leg, two-lane roundabout at the junction of SH25 and SH26.
- Associated drainage, signage, barriers, roadmarkings, landscaping and other ancillary works.
- Services relocations including water mains, electricity, sewer pipes and telecommunications
- The widening of SH26 north of the of the SH25/26 junction to include a flush median and wide left hand shoulder.
- Cultural design features, including:
- 10 Pou
- Waka etching
- Water etching and design on handrails and concrete barriers
- Patiki etching
- Ureia (Taniwha) bridge Pepeha
The 42.8m central span of the new bridge is the main navigational channel for boats. The underside of the central span will be 6.5m above mean sea level, providing sufficient height for large river boats to pass under.
The existing bridge is classified as a Category 1 historic structure by the Historic Places Trust.
Funding
In February 2009 the Government announced it would fund the immediate construction of the Kopu Bridge Replacement as part of its $500 million Jobs and Growth Plan.
Options
Transit New Zealand, the forerunner to the NZ Transport Agency, first appointed consultants to investigate replacing the existing bridge in 1997. They identified two principal replacement options:
- Option 1 – a bridge adjacent to the existing structure.
- Option 2 – a bridge located 700m upstream which would join SH26 at the intersection with SH25A which crosses the Coromandel Range to holiday destinations at Whangamata and Whitianga.
After extensive community consultation, Option 1 was chosen as the preferred option. Option 2 required a bridge that was 250m longer, with significantly higher costs.
Since then, land required for the new bridge has been designated for road development under the Thames Coromandel and Hauraki District Plans and the necessary resource consents have been obtained from the regional council.
