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Waihī Estuary

Waihī Estuary is a shallow intertidal estuary located between Maketū and Pukehina. The estuary contains a range of habitats including saltmarsh, culturally significant shellfish beds and a small remaining area of seagrass. It is a popular location for bird watching and collecting kaimoana.

Drainage and reclamation of lowland saltmarsh/wetlands in the early 1900s has resulted in a highly modified estuary with declining estuary health. There are high nutrient inputs to the estuary, and large regions of nuisance algae (Gracilaria spp.) permanently inhabit the upper estuary margins. Sediment loads to the estuary have been significant, and large areas of the upper estuary are covered in deep mud. Unsafe levels of bacteria in shellfish have prompted numerous public health warnings. 

Estimates in reductions of nutrients and bacteria to stop ecological decline of the estuary indicate significant investment and co-operation are required. A focus catchment programme has been established to provide financial support to landowners in the catchment. The funds will help with environmental projects such as riparian planting, retirement of steep land, pest plant and animal control, and wetland restoration and creation.

Estuary summary

What makes my estuary unique?

Explore the characteristics of this estuary

Overview

Estuary characteristics

  • Significant features
    • Waewaetutuki wetland is the largest wetland on the Pongakawa Plains.
    • Contains several sandbanks and low-lying islands used as roosting sites by birds.
    • Waihi Estuary Wildlife Management Reserve.
  • Total area
    339 hectares
  • Total shoreline length
    28 km
  • Tide
    Spring: 1.7m, Neap: 1.1m
  • Flushing time
    1.68 days
  • Key rivers
    • Pongakawa Stream

What's happening upstream?

See results from monitored river quality sites influencing this estuary

River quality

What's happening upstream?

The physical characteristics and health of estuaries are influenced by the rivers and streams flowing into them. For instance, when it rains the mud and contaminants generated on land can be washed into rivers and eventually flow into the estuary. The health of our rivers and streams can therefore be very important for Estuary Health, and understanding the upstream pressures can help with interpreting estuary monitoring data. Monitoring is undertaken for a range of river health indicators (e.g., water quality and ecology) in many catchments across the region. Where there are monitored river catchments that influence this estuary, these are shown below. You can click through to view monitoring results from these River Quality sites to see current state and how health has changed over time.

What surrounds my estuary?

See land cover information from monitored catchments that surround this estuary

Land cover

What surrounds my estuary?

The physical characteristics and health of estuaries are influenced by local geography and the way we use our land. This is because estuaries are the receiving environments for many of our land use activities. Land cover information can be used as an indicator of land use, therefore knowing the surrounding land cover can help us understand which pressures might be affecting Estuary Health. For example, the sandflats of estuaries surrounded by rural areas will typically contain contaminants related to rural activities (e.g., cadmium from crop fertilisers and copper from fungicides), whereas those surrounded by urban areas are more likely to contain contaminants associated with cities (e.g., zinc and lead from roads and building materials). Where there is land cover information available for nearby catchments, these are listed below. These figures show the types of vegetation and built or natural features that surround the estuary margins and the rivers that flow into this estuary. You can click through to the Land Cover topic to see these land cover classes broken down into further detail, and view changes over time.

Kaikokopu
Pongakawa

What do the Broad Land Cover Classes mean?

Land cover information on LAWA is grouped into land cover classes at two levels of detail – broad and medium. For this overview we are showing the six broad-level classes for the catchment.

  • Forest

    Inclusive of; indigenous and exotic forest.

  • Scrub / shrubland

    Inclusive of; indigenous and exotic scrub / shrubland.

  • Grassland / other herbaceous vegetation

    Inclusive of; tussock and exotic grassland and other herbaceous vegetation.

  • Cropland

    Inclusive of; cropping / horticulture.

  • Urban / bare / lightly-vegetated surfaces

    Inclusive of; natural bare/lightly-vegetated and artificial bare surfaces, and urban area

  • Water bodies
Monitored sites 6

Select a monitored site from the list below

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