The Mangamuka Gorge is the route State Highway 1 takes through the Maungataniwha Ranges to connect Kaitaia and the upper Far North to the rest of Te Tai Tokerau Northland and Aotearoa New Zealand. In August 2022 it was closed due to significant slip damage caused by severe weather.
This project involves urgent repair of slips, including immediate drainage works to divert stormwater away from active slips. Seven slips have been identified as critical as there is a high likelihood that the road could be completely lost in sections. These critical slips must be repaired as soon as possible to enable all other slips to be repaired by the expected opening date of May 2024. The urgency of repair works at the critical slips is exacerbated by ongoing severe weather events causing additional slips and damage to the road.
In addition to the urgency of the works, the project is set within a sensitive and valuable ecological and cultural environment. Engagement with key stakeholders and careful consideration of methodology is imperative to ensure these values are considered appropriately. We’re excited to work in such a special landscape and to be part of this project with the overarching aim of reconnecting whānau, friends, businesses and communities.
Joana leads the team on this project and has undertaken a Biodiversity Assessment across the entire project site to identify the habitat and ecological values relating to the project scope.
She has developed a Biodiversity Management Strategy which underpins the project’s approach to managing the works in this unique environment. The Biodiversity Strategy outlines the approach and plans that will be used to guide management of effects on biodiversity at each individual slip site for the duration of the project.
Together, Waka Kotahi and NZ Environmental Management are committed to building strong relationships and partnering with local iwi and hapū. Hapū representatives are part of the project team and Hapū representatives and kaitiaki from both Te Paatu (manawhenua on northern side and Ngā Hapū ō Mangamuka (manawhenua on the southern side of the gorge) are invited to every site visit by the ecological team to oversee and learn from the specialist work as it’s undertaken. In addition the project team regularly meet with the Department of Conservation.
The Biodiversity Assessment confirmed the expansive, contiguous old growth forest which comprises the Maungataniwha Range contains habitat for a range of ‘Threatened’ and ‘At Risk’ indigenous species. In response, a suite of standalone management plans have been written to define the actions required to ensure that these species are managed appropriately:
• Bat management plan
• Lizard management plan
• Invertebrates management plan
• Bird and kiwi management plan
• Kauri dieback management plan
• Weed and Pest management plan
The Ecological Impact Assessment describes the ecological values present at each individual slip site, along with extent of works and effects. These then identify which management plans need to be implemented at that slip and helps to inform the Compensation Plan that will guide the mitigation and offsetting actions to help balance any ecological effects the project has had.