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Nelson Haven/Paruparuroa

Nelson Haven/Paruparuroa is a relatively large (~1250ha), shallow, well-flushed, seawater-dominated, tidal lagoon estuary located at the southern end of Tasman Bay. The estuary is elongate without side arms and has a simple (relatively straight) shoreline with few embayments. The seaward margin is enclosed within an 8.75km long x 50-100m wide boulder and cobble tombolo, referred to as the Nelson Boulder Bank which protects the estuary from the more exposed Tasman Bay. Large sections of the land/sea interface have been hardened by seawalls, drainage channels and infrastructure (port, roading, housing).

The estuary is valued for its aesthetic appeal, cultural value, sheltered port, biodiversity, shellfish collection, whitebaiting, fishing, swimming, kayaking, walking, boating, and scientific interest. The estuary is recognised as a valuable nursery area for marine and freshwater fish, an extensive shellfish resource, and is very important for birdlife. Community wetland restorations initiatives are underway in the northern part of the estuary.


In 2019, intertidal substrates were dominated by sandy sediments (456ha, 52%) with a relatively low mud content (e.g.<15%), located mostly in the lower and middle estuary. The upper estuary was dominated by firm and soft muds (328ha, 38% of the intertidal area), often with a very high mud content (>90%). The mud extent is relatively high in both a regional and a national context. Intertidal salt marsh 6.7ha (0.6%) is relatively scarce, while seagrass remains a prominent feature (136ha, 15% of the intertidal area). There have been significant losses of this high value habitat over time, in particular salt marsh (99%) and seagrass (50%).

The main pressures identified are elevated muddiness from catchment runoff, and shoreline hardening limiting the estuary's capacity to migrate in response to sea level rise.

Estuary summary

What makes my estuary unique?

Explore the characteristics of this estuary


Estuary characteristics

  • Significant features
    • 6.7 ha intertidal salt marsh 
    • 136 ha intertidal seagrass 
    • 456 ha sand-dominated sediments
    • 328 ha mud-dominated sediments
  • Total area
    1250 hectares
  • Flushing time
    <3 days

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.

Monitored sites 3

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