Mills Street stopbank
Mills Street stopbank
Stage 1 of the Mills Street stopbank upgrade has been successfully completed, and we are proceeding with further enhancements to strengthen flood defences for the Hutt Valley.
Check out this animation showing how we’ve improved the flood protection standard.
The upgraded stopbank provides protection from an approximately 1-in-200 year flood. There’s a 0.5% chance of a flood that size happening in any year.
Greater Wellington built this stopbank to provide urgent flood protection for the community. Some sections were temporarily constructed around high voltage power cables, which are due to be moved in early-mid 2025. When this happens, Greater Wellington will finish the permanent stopbank – this will be Stage 2. We plan to complete the permanent stopbank by the end of the 2025/26 construction season.
Check out this video made while the stopbank was being upgraded.
We have used advanced engineering techniques to withstand flood conditions – they are not just piles of dirt. Despite this, there’s still a risk that any stopbank could be overtopped or breached in a massive flood. Check out Greater Wellington’s flood hazard advice.
River & rock works
The new stopbank is close to the river, and is vulnerable to erosion, so further river works are needed to protect it and the other surrounding assets.
We’ll be placing up to 1,000m of rock lines at key points along the river between Melling Bridge and Kennedy Good Bridge. Rock lines are sloping walls which protect the river bank from erosion. They will be built using the rock which is stockpiled along Harcourt Werry Drive.
To get ready, the team has started relocating willows from along the riverbank north of the Melling Link Bridge. They're being cut down and moved from the rock line location to create an area of soft riverbank edge on the beach just south of Kennedy Good Bridge. The soft edging protects against erosion and slows down the velocity of the water, while also creating a natural habitat for river life.
The willows are laid down horizontally in bundles, so they are partially in the water and partially buried into the river berm. Beneath them, large concrete blocks are set under the beach and the willows are tethered to these with thick manila rope.
We're also installing the first posts for debris fences, which will catch debris during floods, slowing down the floodwater over the berm and helping water return to the river.
In the future we'll plant willow poles here, which will grow up and create natural shelter for other plants and slow water velocities. The aim is to slowly transition from willows to natives here.
Check out this video showing how we’re going to do it.
Trail closure
The eastern side of the Hutt River Trail between Melling Link Bridge and Kennedy Good Bridge will remain closed to walkers and cyclists to enable us to carry out the bioengineering and rock works.
Haul roads and work areas established for the stopbank upgrade will need to be used for the rock and river works.
The site has considerable hazards, such as unstable rock piles and uneven surfaces. We are committed to working to reopen the trail as soon as it is feasible.
Trail users will need to continue following alternative routes. It’s likely that trail closures, on either the eastern or western sides, will be in place until Te Wai Takamori o Te Awa Kairangi programme is completed. We appreciate your patience and cooperation while we undertake this important work.
Working with Mana Whenua
Our programme partnership enables Mana Whenua to work with Greater Wellington to achieve Ora Tāngata (Health of People) Ora Taiao (Health of the Environment) and Ora Wairua (Spiritual Wellbeing). Our procurement criteria will include broader social outcomes and businesses bidding for contracts must show how they will achieve positive social impact for the local community.
We’re working together to develop, implement and monitor best practice holistic care for the river. Construction activities often have environmental consequences. Our flood protection work is managed so that the river can exhibit a more natural form, and so we can include opportunities for positive design, such as regenerating native plants along the river edge and acknowledging sites of cultural significance.
We will continue to monitor earthworks around Maraenuku Pā and ensure that Mana Whenua are involved in the management of archaeological discoveries. The river berms could still hold some taonga (treasures) of the past.
In previous work in Te Awa Kairangi / Hutt River, a partially carved waka was discovered.
Maraenuku Pā
North of the Melling Bridge and within the construction area of the Mills Street stopbank is Maraenuku Pā. The pā (settlement) is an area of cultural significance to Mana Whenua and was located in the vicinity of the electricity substation on Connolly Street.
It was established in the period 1839 to 1846, prior to colonisation, by Ngāti Tama from Taranaki and Ngāti Rangatahi from Ōhura (upper Whanganui River) who were closely allied to Ngāti Toa leader Te Rangihaeata.
Maraenuku Pā was built, and gardens were established even as shiploads of European settlers started to arrive in the Hutt Valley to take up blocks of land they had purchased in London from the New Zealand Company.
The sections purchased by John Boulcott were occupied by his son, who started trying to farm the land. This was close to, and part of the land occupied by Ngāti Rangatahi and in proximity to Maraenuku Pā.
The pressure on areas settled by Māori pā increased and through 1844, Ngāti Tama and Ngāti Rangatahi went on the offensive to protect the land they claimed.
The disputes for the land culminated in what became known as the Battle of Boulcott Farm and those associated with the pā were forced out. Maraenuku pā was demolished by British troops on 27 February 1846.
While no trace of the pā remains today, the history of Maraenuku Pā and the mana associated with that area does. This provides us with the opportunity to acknowledge that site and share its history with the people of Te Awa Kairangi.
We acknowledge Morris Love (Te Āti Awa, Taranaki, Ngāti Ruanui and Ngāti Tama iwi of Taranaki) for providing the cultural history about the project area.