About the dune lakes project

The goal of the project is to improve the water quality of a number of Northland’s dune lakes through a range of work streams that specifically target the threats to dune lakes.

Over the five-year project, we will be:

  • Eradicating water-weeds
  • Controlling pest fish
  • Removing grass carp
  • Stock exclusion through fencing and reticulation
  • Remedying nutrient and sediment inputs
  • Education about dune lakes for school students and local communities
  • Collaborating with tangata whenua and other key partners

Freshwater Improvement Fund

The Ministry for the Environment’s Freshwater Improvement Fund (FIF) commits $100 million over 10 years to improve the management of New Zealand’s lakes, rivers, streams, groundwater and wetlands. As part of the FIF, the Northland Regional Council received matching-funding to improve the water quality of some of Northland’s dune lakes. The total project value is $1,565,950 over five years.

The council has a second FIF project - Waimā Waitai Waioraaimed at improving water quality in the Northern Wairoa River and its tributaries.

Eradicating water-weeds

The workstream includes the eradication of the invasive water weeds Lagarosiphon major and Ceratophyllum demersum (hornwort) from Lakes Ngatu, Waiparera and Ngakeketo.

In the past, a range of options have been used to remove weeds, including mechanical removal, biological control (grass carp) and treating the lakes with targeted herbicides. Each of these methods has been used in Northland in the past, herbicide has proved to be the most successful long-term option so far. Council is planning to use Endothall (Aquathol K) to remove weeds in these dune lakes. Endothall targets the invasive aquatic weeds Lagarosiphon major and Ceratophyllum demersum (hornwort) and does not affect native plants or fish. Microbes in the lake bed break it down into its constituent elements, which are oxygen, carbon, hydrogen and potassium.

More information on Endothall can be found in our Q & As

Controlling pest fish

The workstream is focused on the removal of several species of pest fish from eight lakes. The aim of the project is to:

  • control pest fish in high priority lakes through manual netting, trapping and electrofishing
  • facilitate communities and landowners to continue pest fishing under NRC’s permits

As part of the Freshwater Improvement Fund (FIF) Dune Lakes project, a mail survey was conducted to obtain information on the distribution of four invasive water weeds and exotic fish. The results from this survey have helped the project team to prioritise pest fish control operations.

Removing grass carp

This workstream seeks to remove grass carp from four dune lakes, Swan and Waingata in Pouto, Midgley’s, south of the Kai Iwi Lakes and Heather in Sweetwater. These are not pest fish when permitted to be used in a location but, rather, a management tool. They are notoriously difficult to recapture once their job of eating water-weeds is done and they continue to eat native plants if not removed.

Stock exclusion through fencing and reticulation

This workstream includes fencing out stock at a number of key lakes with some reticulation where required. These lakes include Shag (just north of the Kai Iwi Lakes), Midgley’s (west coast), Waiparera and Wahakari (Far North).

Remedying nutrient and sediment inputs

This workstream, happening between 2020 and 2022 seeks to manage the amount of nutrients and sediment entering select dune lakes through remedial work on drains and gullies and redirection of flows, armoured by riparian planting.

Education, information and community support

This workstream includes a series of ‘get to know your dune lake’ field days for students from local schools and their communities. These field days included hands-on learning sessions looking at lake plants, fish and aquatic insects, and learning about water quality, monitoring and water analysis.

Four education events were held during May – June 2019 at Lake Waikare, Kai Iwi; Lake Kanono, Poutō; and at Lakes Waiparera and Lake Waiporohita in the Far North, in partnership with the Enviroschools and Te Aho Tu Roa programmes.

Over 250 students have attended and 3,400 trees were planted at these events.

A collaborative project

The project works in partnership with mana whenua iwi and hapu to ensure the cultural values and aspirations of mana whenua are considered and included in the planning and delivery of the project.

Community engagement is also key to the success of the project and a number of events are planned to ensure local residents and landowners are informed and have the opportunity to provide feedback and have any queries or concerns addressed.

We are also working with a range of partners to protect and restore some of Northland’s dune lakes:

  • Ministry for the Environment
  • Ngāti Kurī
  • Te Aupōuri
  • Ngāi Takoto
  • Te Rarawa
  • Te Roroa
  • Te Uri o Hau
  • Ngati Whatua
  • Enviroschools
  • Te Aho Tu Roa
  • Department of Conservation
  • Northland Fish & Game Council
  • Far North District Council
  • Kaipara District Council
  • NorthTec
  • Sustainable Business Network’s Million Metres Streams Project

Get in touch

For more information on the project, you can contact the team by email at: [email protected]

Further information