The Manawatū River is a highlight of living in Papaioea Palmerston North. Flowing through the eastern side of the city, significant work has taken place over the years to connect residents to the awa. The same can be said of the Mangaone Stream, which weaves through the city from Flygers Line to Pioneer Highway before it joints the Manawatū River. Both waterways have easily accessible walkways alongside them for people to enjoy. While easy access to these waterways is an advantage, it comes with the risk of flooding and the associated cost of protection. Horizons has invested heavily for decades to safeguard the city’s residents and protect the billions of dollars’ worth of housing, businesses and public assets from flood events along the Manawatū River and Mangaone Stream The Palmerston North Stopbanks Climate Resilience project focuses on planning, investigating, designing, and constructing improvements to flood protection across the city. These initiatives were identified as necessary in a 2019 report by Tonkin & Taylor, which highlighted areas needing enhanced climate resilience. Initial work for this project began in mid-2021 with an assessment of the current state of stopbanks, including a CCTV investigation of Palmerston North City Council stormwater outlets where they pass under Horizons’ stopbanks to determine the state of infrastructure.
The Albert St entrance to the Manawatū River Shared Pathway is one of the most popular access points to the Manawatū River in Papaioea Palmerston North. Palmerston North City Council has done significant work to improve the amenity of the area. The stopbank on the true right of the awa in this area provides protection to the pathway, a main water line and a large portion of the Hokowhitu suburb. If this stopbank was to fail, many homes in Hokowhitu would be at risk of flooding. To improve climate resilience, we constructed a 210-metre-long rock lining.
During the project, we removed 120 tonnes of scrap metal from the riverbank. The origin of this metal and how got into the bank is not yet clear, but removing it was a bonus outcome of the project. This project was complete as of April 2024.
Residents along the Mangaone Stream near Tremaine Ave benefit protection from flood events provided by gabion baskets and stopbanks. However, the gabion baskets are deteriorating and need to be replaced to maintain effective protection.
A secant pile retaining wall is being built behind the gabion baskets. We will remove the gabion baskets once the retaining wall is complete. This method ensures continued protection for the stopbanks throughout the construction phase. This initiative is an important step in providing climate resilience and ensuring sustainable protection for the community and the surrounding areas along the Mangaone Stream.
*Work already completed as part of this programme