Tomaga River

Physical characteristics

Latitude (ºS)-35.84
Longitude (ºE)150.19
Catchment area (km2)191.9
Estuary area (km2)1,21.8
Estuary volume (ML)31410.9
Average depth (m)41.0
Roy et al. (2001) classification5III/5/D
Entrance condition6O
  1. Derived from DECCW (2010) NSW estuaries and coastal catchments spatial database.
  2. Includes area mapped as open water (see note 1), mangrove and saltmarsh areas (Creese R. G., Glasby T. M., West G. and Gallen C. (2009) Mapping the habitats of NSW estuaries. Industry & Investment NSW Fisheries Final Report Series 113. Port Stephens, NSW, Australia.
  3. Based on areas at 0.6 m AHD (Roper T., Creese B., Scanes P., Stephens K., Williams R., Dela-Cruz J., Coade G. and Coates B. (2011) Assessing the condition of estuaries and coastal lake ecosystems in NSW. Office of Environment and Heritage, Sydney).
  4. Estimated by dividing the total volume at 0.6 m AHD by the total surface area of the estuary including mangrove areas but excluding saltmarsh (Roper et al., 2011)
  5. Estuary group: I = oceanic embayment, II = tide dominated estuary, III = wave dominated estuary, IV = intermittently closed estuary V = freshwater bodies
    Estuary type: 1 = ocean embayments, 3 = drowned valley estuary, 5 = barrier estuary, 6 = barrier lagoon, 7 = interbarrier estuary, 8 = saline coastal lagoon, 9 = small coastal creeks, 11 = brackish barrier lake. Evolution stage: A=youthful, B=intermediate, C=semi-mature, D=mature.
    (P. S. Roy, R. J. Williams, A. R. Jones, I. Yassini, P. J. Gibbs, B. Coates, R. J. West, P. R. Scanes, J. P. Hudson and S. Nichol (2001) Structure and Function of South-east Australian Estuaries. Estuarine, Coastal and Shelf Science 53, 351-384)
  6. Entrance conditions: O = open, T = trained, I = intermittent.

Tidal prism

The volume of water moving past a fixed cross section during each flood tide or ebb tide (i.e. slack water to slack water), is referred to as the tidal prism of an estuary.

The following table shows the measured tidal prism at the location specified, along with the tidal range for near the measurement site and at Sydney Harbour.

Location:     175m upstream from entrance boat ramp on 16/9/96

Tide stateFlow
(106 m3
tidal range (m)
Sydney Harbour
tidal range (m)
Ebb flow0.960.861.09
Flood flow 0.960.91.15

Tidal survey

Tidal surveys measure the hydrodynamic behaviour of an estuary during a full tidal cycle. The parameters measured include velocity, water levels, salinity, temperature and pH.

The following tidal surveys have been undertaken on this estuary. A map shows the location and plots of the flows and water levels for the most comprehensive survey.

Copies of tidal survey reports are available from the Estuary Management Program

DateData collectedFigureReport
Sep to Oct 1996Extensive data collection: water levels at ten sites, velocities at three sites, in situ water quality at two sites and twenty-four water quality profiles.1988-50.pdfMHL789
Aug 1996 to Aug 1997Tomaga River Water Quality Monitoring 1997-98.-MHL890

Hydrographic survey

The hydrographic survey provides the depth and physical characteristics of the estuary.

The metadata associated with the survey can be found on the map sheets provided.

Map sheet number DescriptionScale    Size
53500S1.pdfIndex plan & cross section locations1:8000330.3kb
53500S2.pdfTomaga River entrance & Broulee Bay (Tomakin)1:1250428.5kb
53500S3.pdfTomaga River entrance & Broulee Bay (Mossy Point)1:1250451.3kb
53500S4.pdfTomaga River lower estuary1:1250399.4kb
53500S5.pdfCross sections - Tomakin Beach 'Throat' Sections1:1000 H 1:200 V118.5kb
53500S6.pdfCross sections - Tomakin Beach 'Throat' Sections1:1000 H 1:200 V106.7kb
53500S7.pdfCross sections - Tomaga River (downstream George Bass Dr)1:1000 H 1:200 V133.1kb
53500S8.pdfCross sections - Tomaga River (upstream George Bass Dr)1:1000 H 1:200 V115.9kb
53500S9.pdfCross sections - Tomaga River (mid estuary)1:1000 H 1:200 V140.2kb
53500S10.pdfCross sections - Tomaga River (upper estuary)1:1000 H 1:200 V133.8kb
53500S11.pdfCross sections - Tomaga River (upper estuary) & Jeremadra Creek1:1000 H 1:200 V107.8kb
53500a.txtTomaga River xyz dataN/A86.8kb
53500b.txtTomaga River Offshore xyz dataN/A73.3kb
Page last updated: 27 April 2012