Brent Barrett’s Home Planet: Rivers like the mighty Manawatū need room to roam

This photo was taken on February 16, 2004, and shows land near Feilding flooded by the Oroua River. Photo / Mark Mitchell

OPINION

Hard to believe it’s been 20 years. If you were here in February 2004, the power of the Manawatū floods are firmly etched in your memory. Perhaps you were in or surrounded by muddy water on a rural property, saw the river claim animals and homes, or watched the swollen muddy awa press the city’s stopbanks. It plays back like a movie.

We were hit hard. More than 200 square kilometres of farmland went under for extended periods. More than 6000 livestock drowned. Thousands of people were displaced, some for a long time. Outside the city, entire homes were lost as rivers undermined their foundations.

The floods hit our fertile soils and our wallets. Cost estimates range from $150 million to $300m. That’s around $1000 for every person living in the region. We lost great chunks of farmland steep and flat, slipped or eaten away by the floods.

Palmerston North officially recorded 299mm of rainfall that month. Much more fell in the ranges and beyond. It mostly fell in three wild days, starting Saturday, February 14.

Somewhat ironically, I’d spent that Saturday on a wetlands tour in the Wairarapa. Our bus slowly carried us home through torrential rain, into the pitch darkness of the Manawatū Gorge. I remember a solitary road worker valiantly working to keep lanes clear. It was just hours before slips closed the road for 70 days.

The river surged on. Fortunately our city’s stopbanks held fast. Other than being super soggy, most city properties went unscathed. In the future we may not be so lucky, despite constant effort by Horizons Regional Council engineers. While stopbanks are a must, they are not enough.

In my opinion, our best defence is boosting our region’s sponginess. Sponges have an amazing ability to hold and then slowly release water. Trees are spongier than grass. Wetlands are the best.

Rivers advocate Tom Kay at Forest & Bird is doing a splendid job making the case for returning space, being spongy, giving rivers room to roam. It’s the obvious solution for rivers big and wild by nature, including the Manawatū.

This upends actions of the past 100 years. Straightening, armouring, defoliating, accelerating and narrowing define our river management. Here in the city, the awa is increasingly bare and channelled. Even now we see Horizons working to rock line the steep banks at the bottom of Albert St, literally a stone’s throw from homes.

The heating planet makes being flood-ready both urgent and essential. Warmer air holds more water. When it goes up over the mountains it quickly cools. And it rains. The hotter the planet, the bigger the floods. And we’re currently packing on heat at a terrifying pace, at least 1C every 50 years.

We’re already feeling the impacts. Christian Aid has published Counting the Cost, a per person cost comparison of global climate events in 2023. Big ones like the Maui fires and floods in Libya. New Zealand features twice in the top 5. Twice! Cyclone Gabrielle and the Auckland Anniversary floods. Beyond the lives tragically lost, we took economic hits nearing $1000 per person in those regions.

Today I walked by the Manawatū awa. I dipped my feet to cool off. While it brings joy and comfort to our lives, we’re 20 years on from a modern reminder of its wild force. It is not ours. If anything, we belong to her. The awa literally carves through our city. It looms ever larger as we enter a hotter future. The 2004 floods will not be our last. The next ones may well be bigger. Be ready. Start now. Households, neighbourhoods, city and region.

Brent Barrett is an environmental advocate, Green city councillor and scientist. The views expressed here are his own.