Dairy farmers step up to protect New Zealand waterways

Dairy farmers step up to protect New Zealand waterways

23 February 2020

Dairy farmers have shown their commitment to improving water quality in New Zealand by meeting all the targets set out in the Sustainable Dairying: Water Accord to date, but more work lies ahead.

Since the launch of the Water Accord in 2013, the dairy industry has fenced off nearly 25,000 kilometres of waterways around New Zealand and 98 percent of all (Accord) waterways have dairy cattle excluded.

Contaminant risks

Requiring all points on a waterway, where cows cross and return more than once per month, to be either bridged or culverted was one of the mandatory targets for the Water Accord but farmers are being encouraged to go further if they can.

In addition to the mandatory requirements, dairy farmers are encouraged to:

  • exclude stock from all wetlands and smaller streams where practical;
  • apply these stock exclusion practices on any land used for grazing dairy cows.

“Over 11,000 dairy farmers are part of the Accord. They pulled on their gumboots and put in many thousands of hours of time and made significant investment to help improve water quality,” says Alister Body, chair of the Dairy Environment Leaders Group, a multi-sector group formed to be guardians of the Accord.

Covered by culverts

New Zealand farmers have made a massive investment in fencing to keep their stock out of waterways in and around their farms – but in many cases installation of a culvert could provide the same protections and additional benefits for less investment.

Culverts can improve efficiencies on the farm, making it easier and faster for people and stock to move around the farm particularly in the event of high water levels and flooding. Infill area above a culvert pipeline can be grassed therefore increasing production in the paddock concerned.

According to Dairy NZ: “Well planned and constructed crossings prevent damage to the stream bed and reduce the amount of sediment, nutrients and bacteria getting into waterways. They may also improve stock health and production by reducing stress, lameness and the potential of liver fluke.”

Considering for fish passage

Anyone looking to install a culvert or ford that may impede fish passage in a natural river, stream or waterway – or to modify an existing one, needs to seek ‘fish passage authorisation’ from the Department of Conservation (DOC).

P&F Global’s Business Development Manager, Joseph McLean, says: “To ensure the design meets New Zealand’s Fish Passage Guidelines, people should be looking to avoid vertical drops, constriction of flows, water that is too shallow, high water velocities, excessive turbulence, sharp corners, overhanging edges, and smooth substrates.”

McLean says one of the simplest solutions is the installation of a large culvert buried to a sufficient depth so that it simulates the stream environment around it in terms of the channel width, depth and slope.

“With a large culvert that is buried to the right depth you can retain the bank-line inside the culvert and ensure you have the natural substrate (such as pebbles, gravel, silt or plants) present throughout the culvert too,” McLean says.

P&F Global’s EUROFLO pipes are one option for instream structures. Made from high density polyethelene, the pipes are maintenance and rust free, robust (they are one of the strongest plastic pipes on the market) and they come in a range of sizes up to 2100mm in diameter.

For more information: www.dairynz.co.nz/environment/sustainable-dairying-water-accord/

For advice on culverts: www.pandfglobal.com

On fish passage authorisations, visit: www.doc.govt.nz/get-involved/apply-for-permits/business-or-activity/fish-passage-authorisations/ or contact permissions@doc.govt.nz with any questions.

Further information on fish passage and guidance – see www.doc.govt.nz/fishpassage