Wetlands act as the kidneys of the environment, and can remove significant amounts nitrate from runoff through denitrifying bacteria and uptake by plants, markedly improving the quality of water leaving the wetland. They also trap sediment and phosphorus and reduce faecal bacteria.
As one of the most biologically diverse ecosystems, wetlands provide a valuable home for native plants and animals.
Identifying and protecting wetlands on your farm
Wetlands include anything from small on-farm swamps and seeps, to large, regionally recognised areas.
New Zealand has lost 90 percent of its wetland areas from drainage. Protecting even small wetlands on farm adds a lot of value to the environment.
What should I do with wetland areas on my farm?
Fencing wetlands will protect them from stock and allow them to perform to their maximum benefit, reducing the amount of nitrate, phosphorous and sediment entering waterways, improving stock management, protecting land from flood damage and providing a habitat for native wildlife.
Planting wetlands will add further benefit by increasing the uptake of nitrate, trapping more sediment before it enters waterways and increasing the habitat available for wildlife. For more information on what to plant and planting methods, visit the planting page.
Funding and technical guidance on wetlands
Some regional councils offer funding for the development of wetlands. We recommend you contact your regional council before you start work to find out what funding is available.
DairyNZ has been working with NIWA and a technical working group, including representatives from regional councils, to agree on a set of design principles and performance estimates for constructed wetlands.
With support and input from DairyNZ, NIWA has also produced guidelines for constructed wetland treatment of pastoral farm run-off. The guidelines cover general aspects of sizing and siting a wetland, construction, plant selection, wetland effectiveness, and maintenance.
Based on these technical guidelines, DairyNZ will prepare practical resources to support landowners who wish to design and install constructed wetlands on their property.
A farmer's perspective on managing wetlands
In the video below Waikato farmer John Hayward explains the benefits of managing wetlands and his passion for being both environmentally friendly and productive.
- Wetlands secret ingredient to future water quality (20 March 2018)
- Seepage wetlands work wonders (23 February 2018)
- Science shows riparian plantings are keeping streams clean (9 August 2017)