Case Studies

Type of work

Design and installation of dripline irrigation system to irrigate 9.8 hectares of cherries; approximately 12,500 trees.

Problem that needed solving

Pisa View Trust has developed a new cherry orchard on a property located on the Wanaka-Luggate Highway in Central Otago.  The gentle sloping terrain, soil type and arid summer climate meant the block required irrigation to enable the trees to become established and to maximise future cropping potential. To achieve this a low maintenance, high uniformity irrigation system was required.

Size/scale of project

The 9.8 hectare property was effectively a ‘blank canvas’ in 2014 at the beginning of the project.  Since then approximately 12,500 trees have been planted at 2.5m spacing in rows 3m apart and shelter planting has also been established around the property perimeter, and provision for future landscape planting and irrigation on the south side of the property has been allowed for.   This equates to nearly 68,000m of dripline irrigation being laid.

Irrigation Service’s role in project

The contract was awarded to Irrigation Services after preparing a design and costing following several discussions and a site visit.  The proposal presented by Irrigation Services had them as the main contractor; designing the system, selecting, sourcing and installing filtration, valving, pumping, dripline and controllers.  Sub-contractors were engaged to undertake the cabling and electrical work, and building of a 4.0m x 3.0m fully lined and insulated pump shed with roof extraction fans to remove excess heat in the summer months.

Complexities and challenges

Microsprinklers are traditionally used in an orchard environment where the sprinkler is somewhat protected by the tree canopy.  The Pisa View Trust block however, was established using the UFO (Upright Fruiting Offshoot) method.

The UFO system yields a fruiting wall – each tree is comprised of a permanent single horizontal trunk from which renewable fruiting shoots are grown vertically.  Fruit are borne predominantly on spurs but also at the base of 1-year-old shoots, all on vertical wood.

For this reason dripline was used as it enables maximise wetting uniformity, minimises runoff and evaporation.

Irrigable water is sourced from the onsite dam, suctions were installed to pipe water to the block.  Welded baffles were added along the pipe to prevent tracking down the pipeline.

Description of outcome/solution

The system is designed to be low maintenance and with high uniformity.  The irrigation system installed comprises of:

• NaanDan Topdrip pressure compensating dripline emitting 1.6 l/hr at a spacing of 0.6m.  Two lines have been placed on each row 1-1.5m apart, providing an application rate 8mm with in 18hrs.
• Rainbird LX Plus controller allowing full irrigation automation from the controller.
• A variable flow dual pump system to allow total flexibility.
• Arkal self-cleaning disc –type filter. 

Details

Location

Wanaka-Luggate Highway, Central Otago

Client

Pisa View Trust

Year

2017