Hitting Jack Frost where he hits hardest

The stakes are high in frost-prone properties and good frost protection relies on good design and installation. Mike Kirk of Opotiki hit back at Jack with an ADL-designed frost protection system that will cope with temperatures as low as -4 degrees.

Mike Kirk is in a particularly frost-prone area. The water source was a particular challenge for Mike. The water intake stream contained silt and algae and resource consent provisions allowed water to be drawn at the rate of 10 litres per second – not enough to service the 100 litres per second requirements of an adequate frost protection system for the property.

To meet these challenges ADL placed an automatic self-cleaning filtration system at the intake then pumped the water into a storage pond. Water can be drawn from the pond at the required rate of 100 litres per second and pumped to the orchard where it is filtered again with manual disk filters. The pond capacity was chosen to supply enough water for up to three frosts on consecutive days.

Mike’s frost protection system includes sensors for temperature, humidity and potential system failure. The system is monitored from Mike’s home PC and he can leave the whole operation to run automatically or override instructions manually. The whole system needed to be pressure regulated due to elevation differences between the paddocks. Risk of flood on the property meant the system was also designed to operate in flood conditions, as frost often follows the storm.

Water for frost protection is delivered above the vines, while irrigation water is delivered below. Nelson sprinklers give excellent uniformity of coverage which is essential for frost protection. It is one thing to design a system that is capable of delivering enough water to the orchard for frost protection. It is another to achieve the uniformity of coverage to protect all areas of the orchard across all services. ADL use computer modelling to specify the whole system to meet these needs.