Mt Messenger and the wider Parininihi area is a significant landscape and ecological area, which has cultural and spiritual importance to local iwi.
Treading lightly on the land as much as possible guides the project and is expressed through the landscape design approach, design of the bypass, pest management and restoration work.
Our substantial environmental programme involves significant pest management, restoration and landscape planting, and ecological protection. The project aims to greatly improve the natural environment in the Mt Messenger area. The project aims to offset the ecological effects of the construction and operation of the bypass.
Extensive and ongoing pest management
Over decades, pests have seriously damaged some of the mature native forest and habitat surrounding the bypass route.
Intensive, multi-species pest management over an area of 3,650 hectares will be the largest and most comprehensive ecological package developed for a new road in New Zealand.
Reducing risk of harm to native wildlife
Work is already underway to reduce the risk of harming native wildfire during construction and when the road is operational. This involves monitoring and specific environmental investigations of some key species including kiwi, bats and lizards before, during and after construction.
Design elements and other measures are in place to protect freshwater species living in streams along the new road.
Restoration planting of over 120,000 plants covering 32 hectares will help offset the native vegetation removed to build the road and lessen the effects of construction on the local ecology.
Approach to landscape design
The bypass has been designed to go with the form of the land and not against it. The design works sensitively with the Parininihi terrain including Mt Messenger and avoids the culturally and ecologically significant Waipingao catchment.
It keeps low in the landscape by aligning with the Mimi Valley as much as possible and the Mangapepeke Valley.
The landscape design responds to and reflects natural elements, patterns and processes. This includes:
- echoing natural slope angles in the earthworks
- ensuring the revegetation method echoes the natural way plant communities grow at sites over time.
Key environmental design features
The bypass design minimises its impact on the local environment and landscape, including:
- A bridge that carries the road over a stream that feeds into the Mimi River avoids impacting on the significant ecological swamp maire wetland.
- The road is positioned to minimise the impact on the natural water systems of the Mangapepeke valley.
- The tunnel through the main ridge allows uninterrupted movement of wildlife from one side of the new road to the other.
- Stormwater culverts (pipes) that pass under the road have been designed to allow kiwi and other animals to move safely from one side of the road to the other.
- Fencing at all locations along both sides of the road to prevent kiwi (and other ground-based birds) from walking on the road and getting hit by vehicles.
- The route layout avoids as many old and ecologically important trees as possible.