Clarence River

We collaborate with local government to monitor the condition of the Clarence River. Find out more about this estuary and its unique features.

The Clarence River estuary is located on the north coast of New South Wales. Rising in the Macpherson Ranges on the Queensland and New South Wales border, it is classed as a barrier river estuary with a permanently open, trained entrance between the townships of Iluka and Yamba.

The scale of the Clarence River is immense. It is the largest coastal river system with the largest catchment in New South Wales. The river is over 400 kilometres long and the estuary reaches over 100 kilometres inland to Copmanhurst, it’s tributaries include the Mann, Nymboida and Orara rivers.

Estuary health and features

Water quality

Clarence Valley Council in collaboration with the University of New England’s EcoHealth program have carried out detailed ecosystem health monitoring in the Clarence River. The results of the monitoring program, including a detailed water quality report card, are available on the Clarence Valley Council website Clarence Valley Council website.

Find out more about our estuary report cards and what each grade means. Read our sampling, data analysis and reporting protocols and find out how we calculate these grades.

Physical characteristics

Estuary type: Barrier river

Latitude (ºS) –29.43
Longitude (ºE) 153.37
Catchment area (km2) 22,055.1
Estuary area (km2) 132.3
Estuary volume (ML) 283,001.0
Average depth (m) 2.2
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

Over half of the land within the large Clarence River catchment remains forested. About 20% of the catchment falls within national parks and 30% within Forestry Corporation land. Beef production and cleared land for various other forms of agriculture and rural residence make up the next largest land-use type.

The main towns in the catchment are Grafton, Maclean, Dorrigo, Tenterfield, Yamba and Iluka, which contain urban areas that make up less than 1% of the catchment.

Water use

Find out about water use in the Clarence River, including information about major water users, real-time flow data, and environmental and water sharing plans.

Web cam

The Iluka/Yamba bar crossing web camera provides real-time video of conditions within the river entrance immediately offshore to help with bar crossings and boat safety.

National and marine parks

  • The largest conservation area in the Clarence River catchment is Washpool National Park.
  • This estuary does not flow into a marine park.

Citizen science projects

  • The Koalas in the Clarence Valley project collects data on where koalas have been seen in the region.
  • Clarence Valley Council runs the Caring for our Coastal Emus project, which includes an online emu register that community members can report where they’ve seen coastal emus.

Community involvement

  • Clarence Landcare supports a host of local volunteer groups within this catchment that are working work to protect, restore and improve the natural environment.

Local government management

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