Hikurangi Repo environmental improvement

Project typeFlood management
Project value$1.1 million (Better Off Funding)
Project scheduleJune 2027

Several people gather around looking at a map on the bonnet of a car in a paddock.

The Hikurangi Repo is a former 13,000-hectare swamp north of Whangārei that has been progressively drained for agriculture since 1919.

Drainage infrastructure, built mainly in the 1970s and known as the Hikurangi Major Scheme, now supports around 8,000 hectares of farmland through a network of drains, stopbanks and pump stations.

Ageing infrastructure, land-use changes, ground settlement and changing weather patterns mean the scheme is struggling to meet expectations for flood protection, environmental outcomes, climate resilience or tangata whenua partnership.

Taking action

In 2022, Council secured $1.1 million through Better Off Funding to develop a business case and technical reports.

The work aims to restore and protect the natural environment, support sustainable land use, strengthen hapū rangatiratanga and kaitiakitanga, and improve long-term flood management and climate resilience for the Hikurangi area and downstream communities.

Where we’ve landed

Following assessment of a wide range of options, a preferred solution was identified by a project team including Council staff, technical and cultural advisers, hapū and landowners.

Preferred option:

The preferred option is a large-scale, transformational combination of improvements that delivers significant ecological, cultural and economic benefits. Its success depends on landowner participation and funding.

Key improvements include:

gradually returning around 550 hectares to wetland in the Otonga land pocket
improving fish passage through pump station upgrades
optimising pump stations with monitoring, sensors and automated controls
fencing and planting oxbow banks to create riparian buffer zones
managing groundwater levels in peat areas to reduce subsidence and emissions.

Managing the wetland

A new stakeholder trust is proposed to restore and manage areas that change, while Council retains responsibility for unchanged parts of the scheme.

The trust would represent key agencies, hapū / iwi and other stakeholders.

Investment

This solution requires around $53 million in capital over 10 years, which will need a joint approach between local councils, Central Government and other private funds.

While upfront costs are significant, the scheme is expected to generate around $10 million in net operational savings over 10 years once the wetland is established.

Ongoing trust costs would be modest and supported through grants, conservation funding and potential carbon revenue.