4 April 2002 Invitation to Irrigation Field Day – 17th April

Invitation to Irrigation Field Day 

Robert and Leighton Jones, Carew

Wednesday, 17th April, 1.30 pm.

Over the past 12 months I have been working with the Joneses on the design, manufacture and installation of a water turbine scheme on one of the distribution races in the Mayfield/Hinds irrigation scheme. The turbine drives an irrigation pump supplying the Jones' newly installed spray irrigation scheme, incorporating a Briggs Rotorainer. Previously the Joneses used a diesel engine, pump and big gun irrigator with an annual fuel cost of $10000 to $20000 whereas the turbine system will have virtually zero operating costs. Last year, our 3rd Pro Natural Resources Engineering students undertook the design for the turbine scheme and I have continued to assist Robert and Leighton to see the system come to reality.

I have taken some photographs showing the scheme. In summary, approximately 1.2 m³/sec of water is diverted out of the main irrigation race, flows along an elevated channel, falls 4.5 m vertically through the penstock into the turbine and flows from this along the tailrace to re-join the main race three drop structures downstream from where it was extracted. The turbine drives the centrifugal pump through a speed up drive and is delivering about 40 litres/sec @ 560 kPa into the underground mainline. I believe that now the concept has been successfully demonstrated on the Jones' property, there is significant potential for further installations on the Mid Canterbury irrigation schemes. This will save farmers many thousands of dollars in either diesel or electricity pumping costs.

Due to the widespread interest in the scheme, we have decided to have this field day to allow those interested to observe it operating, hear a bit about the design and specifications of the system and ask questions etc. The scheme is located on Withells Rd, between drop structures No's 52 and 54. Withells Rd runs adjacent to the Rangitata River on the Northeast bank and the scheme is about half way between Ealing and the top Rangitata Bridge at Arundel.

We hope that if this is of interest to you, we will see you on April 17th.

Graeme Martin, Senior Lecturer, Natural Resources Engineering Group, Environmental Management and Design Division, Lincoln University, Canterbury, New Zealand