Iwi and Taranaki Regional Council seek help from nature for flooding

8:22 pm on 11 October 2023
Waters are visibly rising at Waitotara River, where the underpass has been closed due to the threat of flooding.

The Waitōtara River in flood in January 2022. Photo: RNZ / Robin Martin

Ngaa Rauru is joining up with Taranaki Regional Council (TRC) to search for "nature-based solutions" to flooding of the Waitōtara River catchment in the face of climate change.

The partnership between Te Kaahui o Rauru and the council has won $150,000 from the Ministry for the Environment (MFE) for a two-year project - Kia manawaroa Waitōtara, kia whakaritea te tangata.

Translated as "let Waitōtara be resilient, let the people be adaptive", the project will look at how to reduce the effects of flooding on communities in the catchment.

TRC rivers manager Chris Vickers told the council's operations and regulatory committee the ministry defined nature-based solutions as meeting social, economic and environmental challenges, while also benefiting human wellbeing, ecosystem services and resilience, and biodiversity.

"Their idea for nature-based solutions is moving away from stopbanks, or rock work, or concrete and trying to see if we can offset or reduce the flood risk using wetlands, or increasing stream capacity, or afforestation."

Marae and hapū would be resourced to be involved and a joint governance team from the council and Te Kaahui o Rauru would oversee the project.

Vickers said the end result will be a draft flood resilience plan for the Waitōtara valleys.

"The funding was purely for modelling and feasibility studies - it wasn't to be used for works on the ground at all."

The application said the Waitōtara catchment covers 1196 square kilometres in the steep eastern hill country and there had been 13 significant, damaging floods since 1869.

"High rainfall events are relatively frequent; this combined with the steep, highly modified environment and narrow, valley-confined flood plains means that flooding in the catchment is frequent and can present a significant threat to life, infrastructure and property."

It said the project aligned with Te Kaahui o Rauru's existing climate change strategy, Ka Mate Kaainga Tahi, Ka Ora Kaainga Rua, which drew on ancestral knowledge and teachings.

"Ngaa Rauru has observed and responded to significant environmental challenges throughout their long history with the awa and have effectively conducted managed retreat in many instances."

Councillor Neil Walker said the Waitōtara was prone to huge floods, and the low-lying lower reaches of the river had led to the township flooding.

"It can rise over 50m in height - it's a tremendous extra lift that it can take. It's got a huge catchment in a very narrow valley and at the bottom end of course where the river bridge is it's at the same level as the sea - so the sea holds it in."

Councillor Mike Davey helped out with clean-up on some of the back-country farms after flooding 10 years ago.

"I've never seen a flood like it, it was amazing."

Vickers said MFE turned down TRC's second application for $250,000 to search for nature-based flooding solutions across Taranaki, but instead approved $100,000 to extend the Waitōtara project flood modelling across the region "even if it's an early model that needs calibration down the track".

Operations manager Daniel Harrison said there was no promise of further money from the ministry, but he expected lessons from Waitōtara would be valid across the region.

"That can be part of business as usual in terms of where we're looking at planting, or protecting wetlands, or what have you - so there's a lot of things we can do without necessarily gaining additional funding."

MFE set up a $5 million pool in the wake of cyclones Hale and Gabrielle in January and February, and encouraged partnerships between tangata whenua and local authorities to bring te ao Māori perspectives to the studies.

Of 41 applications from across the country, 21 were approved.

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