The Mid Canterbury area of New Zealand’s south island is a powerhouse for food production, 10% of which is enabled by Barrhill Chertsey Irrigation Limited (BCI).
BCI is a farmer owned cooperative sourcing water from the Rangitata and Rakaia Rivers, both alpine braided rivers. BCI now has nine main distribution networks, a total of 250km of buried pipelines. The network’s
infrastructure includes river intakes, fish screens, pumping facilities and a small hydro generator.
A cylinder style intake screen manufactured by AWMA was recently installed as a trash screen in a head pond for a new delivery line. This new line delivers around 700 litres per second to farms that previously had no access to water.
The Canterbury area of New Zealand has documented ‘good practice guidelines for fish screening’. This government document notes cylindrical screens:
- have been widely applied, have a good performance record and have been accepted by the resource agencies as positive barrier screens;
- have a proven cleaning capability that removes debris off the screen;
- result in lower maintenance costs;
- are easily accessed if maintenance is required.
AWMA manufacture fish-friendly intake screens with a degree of customisation available. Configurations include ‘T’ or drum style screens that may be mounted on retrieval systems such as a custom framework with electric motor-driven winch or submergible pontoons.
The key benefit of AWMA’s intake screens is the self-cleaning function that eliminates any debris loading or suspended solid build-up from the screen. The self-cleaning function on the cylinder screen utilises one exterior static and one internal rotating brush that can be powered or self-propelled.
Propeller driven screens operate automatically whenever the flow in the suction pipe exceeds a minimum flow velocity, turning an impeller that rotates the screen through a gearbox arrangement.
The Cylinder Screen material and design dictates very low maintenance requirements. The screen medium is wedge wire, available in a variety of slot sizes to suit the application. Manufactured from Grade 304 stainless steel the screen is extremely strong and durable.