A newly completed $41 million stopbank upgrade along the Waipaoa River is promising additional protection for 10,000ha of the flood-prone Gisborne district.
Windy weather welcomed Crown, Gisborne District Council, and mana whenua representatives for the official opening of the Waipaoa Floodbank, near Gisborne, on Thursday morning.
The Government contributed nearly $30m towards the $41m project through Covid-19 and cyclone recovery funding.
The council’s regional river manager Joss Ruifrok said the 63km stopbank protected 10,000ha of land and communities including Manutūkē, Waerenga-a-Hika and Ormond.
“It also protects Gisborne city, airport, and key infrastructure,” Ruifrok said.
“It allows investment into land that would normally be flooded. So it’s an economic hub of Gisborne, the Tūranga Flats, and that stopbank is a significant insurance to flood events, climate change and future risk.”
The project was designed to provide flood protection to 2090, including against an event 25% larger than Cyclone Gabrielle.
It had been a massive project, Ruifrok said.
During construction, the stopbank’s alignment in Waituhi was adjusted to preserve a gum tree and an oak tree with whenua (placenta) buried beneath them.
Maintenance would include annual assessments of stopbanks, pipes, culverts, fences and floodgates.
The council would also respond to public complaints and requests.
At the opening, a karakia was performed on the stopbank before attendees gathered in a gazebo for speeches, waiata and kai.
Mayor Rehette Stoltz said the opening was an opportunity to take ownership of a project that had been in progress since 2015.
“If we go back to just before Cyclone Gabrielle, we were building the last bits on the Ormond side days before Cyclone Gabrielle hit.”
The work had been emotional for staff working alongside communities, and she thanked the Government’s regional development agency, Kānoa, and Regional Development Minister Shane Jones for supporting the project.
“You can see today the fertile land, our marae, our villages all being protected by work that we could do together.
“The climate change of tomorrow arrived in Tairāwhiti today, and we’ve seen quite a bit of this in the last while. So today we just want to celebrate.”
Jones said the project demonstrated the importance of investing in long-term flood protection infrastructure, similar to work undertaken by catchment boards in the past.
“I regard this as the most robust and enduring contribution that any politician can make in the face of wide histrionic debates about climate change. Unless leaders deploy capital to build and develop this type of infrastructure, [it’s] very hard to give ballast to our political narrative.”
Similar work was needed elsewhere in the region and country, and it needed to be considered beyond political divisions, Jones said.
“If you don’t, you will not be sustaining the small villages, the marae and other places where we derive our wealth.”
Former landowner Allan Orchiston said the council had purchased some of his land to make way for the floodbank, before he later decided to move for personal reasons.
Ongoing silt monitoring would be important because the areas now protected by the stopbank had historically accumulated significant amounts of silt during flooding, Orchiston said.
Cyclone Bola in 1988 had brought about 30cm of silt to Orchiston’s property, highlighting the need to record future changes and help generations understand how flooding had altered the landscape.
He also wanted to see weed control and agreements for farmers to graze sheep on the stopbanks and nearby land.
Ruifrok said long-term catchment management would be needed to reduce sediment entering waterways, including retiring unsustainable hill country and planting appropriate trees.
“Stopbanks are, you could argue, the ambulance at the bottom of the cliff. [Stopbanks] are really critical to protecting communities and such a significant asset, but there are other much longer-term sustainable aspects to be considered as well to be holistically managed.”
Further flood protection projects are planned across Tairāwhiti.
A consent decision on the Te Karaka stopbank was expected on November 9, with construction targeted for summer 2027.
In Tokomaru Bay, plans included a short floodbank on Mangahauini Rd, behind Tokomaru Bay School, and widening the Waiotu River to protect Hatea-A-Rangi School, Ruifrok said.
No structural flood protection projects had been funded for Tolaga Bay at this stage, but design work on a stopbank was underway so the project could proceed if funding became available.
LDR is local body journalism co-funded by RNZ and NZ On Air.
