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Tauranga Harbour

Te Awanui (Tauranga Harbour) is a shallow tidal estuary which is the largest estuarine system in the Bay of Plenty. The harbour has two openings where large volumes of water are exchanged with the tide. The harbour and its margins comprise numerous bays, estuaries, wetlands and saltmarsh. It contains the largest remaining seagrass beds in the Bay of Plenty. It supports New Zealand's largest commercial port and one of the fastest growing citys in New Zealand. The entire Tauranga Harbour is identified as an outstanding natural feature and landscape.

Large modifications have occurred in the catchments from pre-European settlement, with clearing and modification of the land for farming, logging and mining, draining of wetlands and reclamation of harbour areas. Sedimentation has increased, causing large muddy regions in the sub-estuaries of the harbour, whilst the open harbour areas have retained sandy sediments which support vast shellfish and seagrass beds. Nutrient enrichment has resulted in occasional large blooms of sea lettuce (Ulva). Heavy metal runoff has shown increased levels close to urbanized areas. There is variability in the health of the harbour depending on where you look.

Estuary summary

What makes my estuary unique?

Explore the characteristics of this estuary


Estuary characteristics

  • Significant features
    • Has internationally significant wetlands and waterfowl and ranked as an "Outstanding" and "Site of Special Wildlife Interest".
    • Supports valuable kaimoana fisheries.
    • Contains 18+ distinct sub-estuary environments.
    • A significant area of traditional history for 3 Tauranga Moana iwi: Ngāi Te Rangi, Ngāti Ranginui and Ngāti Pūkenga. 
    • Shell and sandbanks used by indigenous birds.
    • Athenree Wildlife Refuge (38.5 ha).
    • Margaret Jackson Wildlife Management Reserve.
    • Matakana Island Wildlife Refuge.
    • Waikareao Wildlife Refuge (225 ha).
    • Egg Island Conservation Area.
    • A further 30+ terrestrial conservation areas totalling around 700 ha.
  • Total area
    21,714 hectares
  • Total shoreline length
    399 km
  • Tide
    Spring: 1.7 m, Neap: 1.1m
  • Flushing time
    9.01 days
  • Key rivers
    • Wairoa River
    • Waimapu Stream
    • Aongatete River
    • Kopurererua Stream
    • Tuapiro 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.

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.

Te Rereatukahia
Te Mania

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 68

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