Wetlands

What is a wetland?

All the permanent or seasonally wet areas of your farm are small natural wetlands, including:

Bogs: receive all their water from rain, so are not enriched by nutrients from adjacent land or underlying mineral soils. Being almost constantly waterlogged, they are poorly aerated and usually acidic.

Swamps: fertile wetlands that are fed by both groundwater and surface runoff so receive a regular supply of nutrients and sediment from adjacent land.

Seeps: occur at the bottom of hill slopes where groundwater comes to the surface. Can be permanent or seasonal and exist on all soil types. Can be nutrient-rich because they receive runoff from paddocks and often cows have direct access to them. Losses of sediment and E. coli to water from these areas can be significant during rainfall or overland flow.

Wet areas in paddocks: swampy or boggy places where drainage is poor, such as hollow or valley bottoms. Could be fed by rainfall or high water table and tend to be on heavier soils. Risk of overland flow to waterways is less as they are often not connected to waterways, although they are still nutrient ‘hotspots’.

Riparian wetlands: wet or boggy places bordering waterways, drains, and lakes. Can be nutrient-rich, like seeps, and risk sediment and E. coli loss to waterways.

What does a wetland do?

Wetlands have an important part to play in reducing our environmental footprint. Throughout New Zealand, wetlands support the greatest concentration of plants of any New Zealand habitat. This supports native birds, fish and invertebrates.

Wetlands help reduce flooding by acting as a sponge, and improve water quality by trapping, filtering, and removing nutrients and contaminants, especially sediment, nitrogen and phosphorus.

The following diagram shows how wetlands work in a farm environment.

Managing and protecting wetlands

Managing and protecting even small wetlands on a farm will add a lot of value to the environment and could be an action included in your Freshwater Farm Plan.

The main steps in managing a wetland, no matter what type it is, are:

• Keep stock out: the Resource Management (Stock Exclusion) Regulations 2020 require all stock to be excluded from natural wetlands. For more, see our stock exclusion page.
• Keep it wet: successful wetlands need to remain wet for a large proportion of the year. This includes ensuring that new and existing drains don’t drain water from that area.
• Control weeds and pests: this enables existing and newly established wetland plants to thrive.
• Plant if needed: sometimes, excluding stock and controlling weeds is all it takes for wetland plants like sedges and rushes to grow back naturally. Planting other native plants can help improve the biodiversity and aesthetics of your wetland. For more, see our riparian planting page.

Wetland rules and regulations

Rules apply if you’re planning work in or around natural wetlands. Some actions may need a resource consent, while others may be prohibited. Before undertaking any activity within or near an existing wetland, you should seek advice from your regional council and check the National Environmental Standards for Freshwater. For more information, see our river structures and wetlands regulations page.

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.