At a Glance
SUPPLIES UP TO 8 M3/S OF IRRIGATION WATER
Highbank Pumping Station is the result of a partnership between Trustpower, Barrhill Chertsey Irrigation and Electricity Ashburton. Water is extracted from the Rakaia River, into a short canal, alongside the existing Highbank Power Station tailrace to the new pumping station. It’s then piped across the tailrace, up the existing penstock and into the Rangitata Diversion Race for delivery to farmers.
Six pumps have been installed, each capable of pumping one cubic metre a second (m3/s) of water. We envisage the pumping station will eventually be capable of supplying the Rangitata Diversion Race with 8m3/s of irrigation water.
The pumps were supplied by KSB, one of the world’s largest pump makers. They are driven by 1.55 MW Siemens motors. A sophisticated starting system ensures the local electricity distribution network is not negatively impacted.
One challenge of this project was making and installing a large bifurcation or ‘tee’ to connect the new pipeline to the original penstock. We created a huge air chamber (40 cubic metres) to accommodate the varying pressures in the pipeline and penstock. The solution has performed well.