Coastal flats, historically grazing bull beef, converted to 425ha, 1200 dairy cow milking platform.



Limestone Downs is a 2500ha effective coastal property south of Port Waikato running sheep and beef. Dairy conversion has seen 425ha of predominately coastal flats transitioned to dairy which will support up to 1200 cows.  

AgFirst Engineering followed the project from conception to completion, providing onsite expertise throughout the project.

The waste water treatment system is designed so that all waste water from the cowshed, yard areas, feed pad and silage storage bins are gravity fed into the solids removal bunker and effluent storage pond. Waste water is then applied to land using a low application system to ensure surface ponding of waste water does not occur.

A feed pad flood washing system has been designed enabling filtered green water to be pumped from the effluent pond into storage tanks positioned above the feed pad. Green water is used to flush waste from the feed pad following stock use. The flood wash system using recycled green water works very effectively, reducing the required freshwater take volume.

The stock water system has been designed enabling a total flow of 84000 litres per day to be delivered to cows grazing within the dairy platform. Water is sourced from on farm spring sources delivered to a central pumping station.

All design work was completed working closely with Limestone Downs staff and advisers, enabling a customised design solution to be achieved.


Design Specifics:

AgFirst Engineering involvement in the Limestone Downs Dairy conversion included:

  • Preliminary investigation budget costings, development for dairy effluent treatment and land application, farm water supply reticulation and land drainage pumping station implementation.
  • Resource consent application compiling and presentation to Waikato Regional Council for
    • Water take (stock and cowshed water)
    • Drainage pumping station construction and operation
    • Large culvert installation
    • Earthworks
  • Dairy shed, feedpad and silage storage bin layout to enable required earthworks to ensure all waste water, silage leachate and flood wash is able to gravity feed into waste water treatment system.
  • Design and build dairy effluent solids removal, storage pond and low application waste water irrigation system.
  • Design and build farm water reticulation system.
  • Design and build land drainage pumping system enabling floodwater to be discharged into adjacent river.
  • Design and build feedpad flood wash system using recycled green water from the effluent storage pond.