Taming the river’s run

Winter brings out the worst in rivers. Janine Rankin talks to an engineer who tries to manage them.

Rivers do not always stay where people want them to.

That is why Horizons Regional Council engineering officer for the central team Jenna Buchanan spends as much of her time talking to people as she does figuring out how to manage rivers.

In particular, she is involved with the Manawatu River, from the Ashhurst bridge to the sea – one of Horizons’ 34 river and drainage schemes.

She has a degree in surveying and a wealth of technical knowledge, but says having communication skills is just as important.

‘‘It’s not just about managing the river, but the expectations of people around the river.

‘‘We try to keep the river where it is, but that’s something the river does not like to do.’’

That meant having to work on relationships with people living close to the river, helping them understand how much was realistic.

Many of those people, whether farmers or homeowners in Riverdale, had Horizons-owned stopbanks running through their private property, and the council needed good relationships with them so they had access for construction, inspections and maintenance.

At the moment, there are some practical issues at the top of her work list. One of them is finding rocks. She is designing a couple of projects at the moment – rock lining for the Mangaone Stream where the city council is building a pathway extension at the

back of the racecourse, and repairing erosion damage downstream from the Fitzherbert Bridge.

She has to figure out how much rock, of what size, will be needed to create neatly-interlocked walls with firm foundations.

Sourcing rock has been a challenge for the past couple of years while construction of the Transmission Gully highway has the market cornered.

During a wet winter, she has also had plenty of work to do out in the field, checking stopbanks before, during and after floods.

And then, for something rather different, she is closely involved with planning for the development of Waitoetoe Park.

PHOTO: DAVID UNWIN/STUFF Horizons Regional Council engineering officer Jenna Buchanan plans repairs for an area of erosion on the bank behind the Esplanade.