Tomahawk Lagoon

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Consultation has concluded

Tomahawk Lagoon is located at the southern end of Otago Peninsula and consists of two shallow brackish water lagoons. These are joined by a narrow channel and a weir structure, and share a common sea outlet.

The area is a wildlife refuge managed by the Department of Conservation and contains the threatened plant species Isolepis basilaris on the margin of the lagoon. It’s also a regionally significant wetland habitat for waterfowl and waders with a variety of bird species present. The area is part of a chain of feeding habitats along the coast used by migrating birds, and is an important habitat for native fish and eels. The area is important ecologically as it is defined as a marsh and less than 15% of original marshes remain in Otago.

Citizen Science water quality monitoring is undertaken by ECOtago monthly. Their results show that turbidity, E. coli, nitrates and phosphate levels are elevated within the lagoon, which is affecting water quality. Cyanobacteria, a toxic bacterium that can be harmful to humans and animals, is also regularly found within the lagoon in summer months.

Following a scoping exercise in 2017-18, the community agreed that the issues for the area are:

  • Algal booms
  • Water quality data
  • Swimmable water
  • Pest management (animals and weeds)
  • The weir
  • Flooding
  • Sedimentation

The goals that were identified were:

1. The natural environment of Tomahawk Lagoon and its ecosystem to be protected and enhanced

2. Appropriate recreational uses of Tomahawk Lagoon to be protected and enhanced

Priority projects

A number of projects were suggested by the community to achieve these goals. Some would involve ORC and others would involve DCC or community organisations. The majority of projects would rely on confirmed funding to enable them to go ahead.


Hear Libby Caldwell, Project Delivery Specialist, talking about Tomahawk Lagoon and how the community can have a say on which water quality projects should be prioritised on this podcast from Otago Access Radio here.

Tomahawk Lagoon is located at the southern end of Otago Peninsula and consists of two shallow brackish water lagoons. These are joined by a narrow channel and a weir structure, and share a common sea outlet.

The area is a wildlife refuge managed by the Department of Conservation and contains the threatened plant species Isolepis basilaris on the margin of the lagoon. It’s also a regionally significant wetland habitat for waterfowl and waders with a variety of bird species present. The area is part of a chain of feeding habitats along the coast used by migrating birds, and is an important habitat for native fish and eels. The area is important ecologically as it is defined as a marsh and less than 15% of original marshes remain in Otago.

Citizen Science water quality monitoring is undertaken by ECOtago monthly. Their results show that turbidity, E. coli, nitrates and phosphate levels are elevated within the lagoon, which is affecting water quality. Cyanobacteria, a toxic bacterium that can be harmful to humans and animals, is also regularly found within the lagoon in summer months.

Following a scoping exercise in 2017-18, the community agreed that the issues for the area are:

  • Algal booms
  • Water quality data
  • Swimmable water
  • Pest management (animals and weeds)
  • The weir
  • Flooding
  • Sedimentation

The goals that were identified were:

1. The natural environment of Tomahawk Lagoon and its ecosystem to be protected and enhanced

2. Appropriate recreational uses of Tomahawk Lagoon to be protected and enhanced

Priority projects

A number of projects were suggested by the community to achieve these goals. Some would involve ORC and others would involve DCC or community organisations. The majority of projects would rely on confirmed funding to enable them to go ahead.


Hear Libby Caldwell, Project Delivery Specialist, talking about Tomahawk Lagoon and how the community can have a say on which water quality projects should be prioritised on this podcast from Otago Access Radio here.

Consultation has concluded
  • Priority projects for Tomahawk Lagoon

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    CLOSED: This discussion has concluded.

    Ecological Assessment

    Investigate the balance between the needs of human interaction with the lagoon and wildlife (hydrological function, ecology, wildlife, walking tracks, flood hazard).





    Water Quality Data

    Have a permanent water quality monitoring site installed to establish baseline data and ensure mahika kai safety.

    Outlet


    Sediment management around the outlet to ensure that there is flushing and better flow of water in and out of the lagoon.


    Citizen science

    Support ongoing water quality monitoring programme as a way to generate data for the catchment and as an important community engagement tool.


    Education and awareness

    Engaging, educating and inspiring the local community to support this action plan. This area is to be a source of learning for local schools. Development of resources to assist with this engagement and education.


    Pest and weed programme

    Support and provide resources to assist neighbours to form groups to tackle weed and pest species in a combined and aligned effort. The aim is to control predators of birds and to minimise impacts on the native forest in the area and to control weeds where fast growing exotic species out compete natives.


    Fencing project to exclude stock from waterways

    Support for landowners to exclude stock from waterways to protect waterways.


    Native plant restoration

    Support, advice and resources provided to aid landowners with riparian planting projects to restore the ecosystem


    Research which riparian plants will be most effective


    Leverage off relationships with university/schools

    Community Planting Events


    Community planting days and events where people can come together to help restore the lagoon and its catchment.

    Catchment group formed and supported


    Joining of agencies and the community. Establish a ‘Friends of Tomahawk Lagoon’ with members of the community and stakeholder representatives

    Recreation (boardwalk, walkway, boat ramps)


    Identify opportunities with Department of Conservation and private landowners for sections surrounding the lagoon to be restored and developed for public access.

    Support nurseries run by Yellow Eyed Penguin Trust or Tomahawk Smaills Beach Care Trust


    To provide locally grown plants for planting within the catchment.

    Study of flora and fauna present in this area


    To help understand why we should protect the area.

    Algae removal


    Use technology to reduce the frequency of algal blooms in the lagoon and enhance mahika kai and recreational opportunities. Investigate floating wetlands.

    Sediment removal around weir (top lagoon)


    Remove sediment from around weir to improve water quality by increasing the turnover of water between upper and lower lagoons. Upgrade weir.

    Stormwater in urban areas drains to the sea


    Need to help educate the public and developers about stormwater.

    Storytelling exercises


    What did the catchment look like historically and how was it used? Use visuals and tie this into the ecological assessment. Stories from mana whenua.

    Pest fish in the lagoon


    Investigate the impacts environmentally vs recreationally.


    Click here to select your three priority projects.