Waipoua river

Image: Sarah Wilcox | Creative Commons

Introduction

The Waipoua River in Northland is one of 14 priority catchments in our Ngā Awa river restoration programme.

The Waipoua River runs through Waipoua Forest and has a small area of farmed land in the headwaters and 950 ha of regenerating forest, food-producing land and pine forest near the coast.

Waipoua Forest is a kauri forest that with adjoining Mataraua and Waima forests, is the largest remaining tract of native forest in Northland. It is one of Northland’s main tourist sites and has a high national and international profile, being home to Tane Mahuta and other ancient, treasured kauri trees.

The goal for this project is to restore the river and add to the significant long-term restoration work that is already being carried out in the catchment.

See a map of the Waipoua river catchment (PDF, 948K)

Treaty partner and project partners

Waipoua Forest is the ancestral home of Te Roroa, an iwi based on the west coast of Northland. The strong partnership between DOC and Te Roroa underpins the project.

Our project partners include Northland Regional Council, Reconnecting Northland, Te Toa Whenua, Waipoua Forest Trust and Native Forest Restoration Trust.

Current restoration work

Modifying a ford to enable fish to pass

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Ford on lower Waipoua River. Image: Sarah Wilcox

A ford on the lower section of the river was preventing most native fish from moving upstream into the higher parts of the catchment. The river is large at this point and subject to flooding, but the ford provides access for local people and logging trucks. 

Fixing the ford is a significant project because many different fish species need access up and down the river during times of low flow as well as during floods.

Monitoring fish communities above and below the ford began in 2016. This work led to fish ramps being installed at both sides of the ford in June 2017. Two more ramps were installed in Sept 2019. In February 2020, boulders in the stream were moved to make the ramps easier to use.

Further monitoring has shown that not all fish species can get past the ford. Modifications to the upstream edge of the ford are planned because it currently acts as a weir and reduces fish movement upstream. It also stops the riverbed’s natural movement during floods.

Headwater farmland

Several large streams and wetlands are located in farmed areas at the head of the catchment. The freshwater values in this area were first assessed in March 2017. This assessment provided background for discussions with the farm owner and Northland Regional Council about installing fencing and native planting beside the waterways. The work is intended to prevent nutrients, sediment and faecal contaminants entering the river water.

Water quality monitoring

DOC and Te Roroa are working with the Northland Regional Council monitoring team to expand and improve real-time monitoring of the quality and quantity of river water. The council is also part of a technical group supporting the river restoration.

Erosion studies

Although it is a natural process, bank erosion contributes to a build-up of sediment in the river. A survey of the river downstream of the state highway bridge will identify and characterise where erosion of the banks is occurring. Several of the sites will be surveyed in detail to enable changes to be tracked. Depending on the survey results, restoration work at one demonstration site will be trialled.

Replanting with native plants including kauri

Previous replanting in the catchment was successful in converting farmland to kauri forest. A pilot-scale nursery in the lower catchment to grow locally-sourced natives for replanting is operating and planning to scale up the work is underway.

Weed management

Large areas of the lower catchment are covered in weeds including wilding pines, tobacco weed, ginger, pampas, montbretia and gorse. Long term control and replanting with natives is being carried out in some areas – different approaches are being trialled find the most cost-effective method. DOC undertook extensive weed control work on the riverbanks from the ford to the headwaters from 2001–2010. 

Waipoua catchment restoration work

Te Roroa iwi initiated a project called Te Toa Whenua to restore land returned to Te Roroa as part of the iwi settlement. Te Toa Whenua received support from the DOC Community Fund in 2016/17 and in 2019/20. Te Toa Whenua has also been supported by other organisations including Reconnecting Northland, Northland Regional Council and the Tindall Foundation.

Te Roroa received funding from the Ministry of Environment's Freshwater Improvement Fund in 2017. The project sought to address the major pressures on the river and fence headwater tributaries and wetlands to exclude stock, identify and protect eroded areas to reduce sediment run-off and provide instream habitat for native fish species.

Te Roroa have retired more than 600 hectares of plantation forest to create a continuous corridor of native revegetation along the lower margins of the river.

Kauri dieback is present in Waipoua Forest and its management is a priority for Te Roroa and DOC. To minimise the spread of the disease, walking tracks and predator trap lines have been closed or re-routed to avoid high-risk areas. Reducing pig numbers to low levels is likely to reduce the risk of infected soil being spread around the forest. This also reduces sediment entering the river via tributaries in the upper catchment. Biosecurity New Zealand and Northland Regional Council have used Lidar (a precise mapping technology) to support this work.

The Waipoua Forest Trust has a number of projects in the area, including replanting, pest trapping and dotterel monitoring at the coast, including near the Waipoua River mouth.

The Native Forest Restoration Trust owns several blocks of regenerating forest in the Waipoua catchment and continues to seek funding to secure other land in the catchment.

Native species present

A range of taonga and threatened species are present in the catchment:

  • fish: shortjaw kokopu, longfin eel/tuna, lamprey/pihoro/kanakana, koaro and torrentfish
  • plants: kauri forest, a Nationally Critical fungus (undescribed genus—Trichocomaceae), a moss (Fissidens integerrimus), native oxtongue, king fern and Bartlett’s koromiko
  • birds: Australasian bittern (Nationally endangered), North Island brown kiwi North Island kaka, kōkako, brown kiwi and fernbird/matātā
  • other species: land and kauri snails, forest ringlet butterfly, Otekauri (ground weta) and Waipoua beetle

Contact

Email freshwaterrestoration@doc.govt.nz for more information.

About Ngā Awa

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The Ngā Awa river restoration programme began in 2019. It's an extension of our existing work to slow the decline in New Zealand’s biodiversity. The programme focuses on a diverse range of priority river catchments across the country.

Learn more about Ngā Awa's work

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