A NSW Government website

Nelson Lagoon

Our water quality monitoring program has shown Nelson Lagoon to have excellent water quality. Find out more about the estuary and its unique features.

Nelson Lagoon is located on the far south coast of New South Wales. It is classed as a barrier river estuary and its entrance remains open to the ocean.

The estuary contains wetlands that are listed in the Directory of Important Wetlands in Australia for providing significant saltmarsh habitat.

The estuary has several small waterways, such as Duckhole Bay and Sandfly Bay. The main tributary to the lagoon is Nelson Creek.

The lagoon is located within Mimosa Rocks National Park and is a popular for swimming, fishing and birdwatching.

Water quality report card

As part of our water quality monitoring program we assess the water quality and ecosystem health of an estuary using a range of relevant indicators. We sample a subset of the estuaries between Wollongong and the Victorian border every 3 years. The most recent sampling in Nelson Lagoon was completed over the 2020–21 summer, when 2 sites were sampled on a monthly basis.

This report card represents 2 water quality indicators that we routinely measure: the amount of algae present and water clarity. Low levels of these 2 indicators equate with good water quality.

B

Algae

A

Water clarity

A

Overall grade

The report card shows the condition of the estuary was excellent with:

  • algae abundance graded good (B)
  • water clarity graded excellent (A)
  • overall estuary health graded excellent (A).

Grades for algae, water clarity and overall are represented as: 

  • A – excellent 
  • B – good 
  • C – fair 
  • D – poor 
  • E – very poor.

Go to estuary report cards to find out what each grade means, read our sampling, data analysis and reporting protocols, and find out how we calculate these grades.

Historical water quality grades

We have monitored water quality in Nelson Lagoon since 2011. This table shows the water quality grades for this estuary over that time.

YearAlgaeWater clarityOverall grade
2011–12AAA
Physical data

Physical characteristics

Estuary typeBarrier river
Latitude (ºS)–36.69
Longitude (ºE)149.99
Catchment area (km2)27
Estuary area (km2)1.3
Estuary volume (ML)1077.8
Average depth (m)0.9

Notes: km2 = square kilometres; m = metres; ML = megalitres.  

Water depth and survey data

Bathymetric and coastal topography data for this estuary are available in our data portal.

Land use

The catchment of Nelson Lagoon falls almost entirely within Mimosa Rocks National Park. Urban and grazing areas account for 2% of land use.

Get involved

National and marine parks

Citizen science projects

  • The Far South Coast Conservation Management Network supports the local community to better manage native biodiversity. The network organises citizen science projects, provides information for private landowners, manages a local plant database, and coordinates events.

Community involvement

Seafood harvest area status

The NSW Food Authority website lists the current status of oyster/shellfish harvest areas.

Aerial view of Nelson Lagoon flowing into the ocean, with visible sandbanks at the river mouth and a nearby town along the waterways.

Aerial view of Nelson Lagoon estuary.

Local government management

Local councils manage estuaries within their area unless the estuary is attached to a marine park.

Bega Valley Shire Council manages this estuary.

Threatened species

Nelson Lagoon provides important habitat for waterbirds and shorebirds, including hooded plovers and pied oyster catchers.

Read more about the biodiversity in our estuaries.