Clever use of gravity revolutionises irrigation, especially in remote NZ farms.

An innovative new irrigation device, the Carrfields HydroDrive, is making real waves with farmers and growers around the country.

The device uses excess water pressure gained from gravity to power pivots in irrigation systems, eliminating or reducing the need for electricity or diesel and providing a cheaper, more sustainable option for farmers.

Brendan Hawes is the national sales manager for Carrfields Irrigation and says the HydroDrive is particularly useful in areas where electricity is inaccessible.

"Hilly, remote farms often have issues getting electricity to irrigation systems," he says. "Diesel can be used but this just adds another job to the farmer's already busy day."

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Most of New Zealand's irrigation water is sourced from rivers that flow downwards from mountains to the sea. In many cases before the HydroDrive was developed, the excess pressure produced was not captured and used.

The Carrfields HydroDrive works by capitalising on that excess pressure. The water runs through a turbine and allows the T-L hydraulically-driven centre pivot irrigators (low pressure devices) to operate without electricity or diesel, eliminating the need for pumping and its attendant costs.

The first HydroDrive prototype was installed on the North Otago Irrigation Scheme last year and Hawes says there has been lot of interest from farmers since the first successful trial.

"Four further HydroDrive systems have been installed since then and farmers are excited about the opportunity to have lower operating costs," he says.

One of the farmers is Brent Craig from Bowalley free-range egg farm. He had already installed solar panels and wanted to move into a more sustainable form of irrigation with the aim of being self-sufficient.

"At Bowalley free range, our conversation with our customers is part of our daily focus and we have to look at every aspect of the business as we grow the crops to make the feed for the birds to lay the eggs we supply our customers," he says.

"HydroDrive is part of looking at everything we do to ensure the footprint from our activities is as small as we can make it."

A previous prototype of HydroDrive was developed around eight years ago and was in place near Methven but Hawes says it was essentially just "proof of concept" and not fully functional.

Carrfields Irrigation (with the help of a final year project group from the University of Canterbury's Mechanical Engineering department) undertook further research to develop, standardise and commercialise what would become the Carrfields HydroDrive.

The device works by translating water pressure to hydraulic oil pressure through a turbine coupled to the standard T-L hydraulic pump. The oil pressure produced powers hydraulic motors at each wheel through high-efficiency gearboxes.

The development team discovered locally sourced pumps and other components worked just as effectively as the more expensive, imported components – so costs were kept to a minimum.

Hawes says the HydroDrive is still being developed and tweaks are likely to improve its functionality further.

"As with any new product, every model will be further refined to ensure it provides users with the best possible outcomes."