Tomaga River

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

Tomaga River is a barrier river estuary with an open entrance. It is located on the south coast of New South Wales, south of Batemans Bay.

The estuary hosts a range of habitats such as intertidal mudflats, mangrove forests, saltmarshes, swamp-oak woodlands and is a habitat protection zone as part of Batemans Marine Park.

Estuary health and features

Water quality

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 the Tomaga River was completed over the 2008–09 summer when 2 sites were sampled on a monthly basis.

Tomaga River water quality report card for algae and water clarity showing colour-coded ratings (red, orange, yellow, light green and dark green, which represent very poor, poor, fair, good and excellent, respectively). Algae is rated 'excellent' and water clarity is rated 'good' giving an overall rating of 'excellent' or 'A'.

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.

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

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

Eurobodalla Shire Council have a long-term water quality monitoring program in the Tomaga River, based on the same sampling and reporting methods as our state-wide program. The results of the monitoring program, including a detailed water quality report card, are available on the Eurobodalla Shire 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

Entrance
location
Latitude (ºS) –35.84
Longitude (ºE) 150.19
Catchment area (km2) 91.9
Estuary area (km2) 1.8
Estuary volume (ML) 1410.9
Average depth (m) 1

Tidal exchange volume

Tidal exchange volume or tidal prism data is available for this estuary.

Tide state Flow
(106 m3)
Local tidal
range (m)
Sydney Harbour
tidal range (m)
Ebb flow 0.96 0.86 1.09
Flood flow 0.96 0.9 1.15
Notes: km2 = square kilometres; m = metres; m3 = cubic 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 Tomago River catchment is moderately disturbed with almost 20% cleared for urban and rural residential areas and grazing at Tomakin, Mogo and Woodlands. About 80% of the catchment is forested.

National and marine parks

  • There is no conservation area in the Tomaga River catchment area.
  • The Tomaga River estuary flows into Batemans Marine Park.

Citizen science projects

  • iNaturalist’s Plants of Eurobodalla is a citizen science project that monitors plants found in the Eurobodalla region.
  • The Budawang Coast Nature Map is an online data platform the community can use to record and identify biodiversity. Data collected is used to map the distribution of native plant and animal species from Moruya up almost to Kiama.

Community involvement

Tomaga River