Narrabeen Lagoon

Physical characteristics

Latitude (ºS)-33.70
Longitude (ºE)151.31
Catchment area (km2)152.4
Estuary area (km2)1,22.3
Estuary volume (ML)35251.6
Average depth (m)42.3
Roy et al. (2001) classification5IV/8/B
Entrance condition6I/(O)
  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:     1.5km from the entrance on 11/9/80

Tide stateFlow
(106 m3
tidal range (m)
Sydney Harbour
tidal range (m)
Ebb flow0.280.141.08
Flood flow

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
Dec 1979Narrabeen - current metering at a line just downstream of main road bridge and seven tideboards.-MHL566
Mar 1980Narrabeen - echo sounding.-MHL566
Sep 1980Narrabeen - current metering same as 20/12/79.1988-34.pdfMHL566
1983Narrabeen - pilot dredging program (August-December).-MHL412
Nov 1983Narrabeen - suspended sediment sampling.-MHL412
Nov 1983Narrabeen - Float tracking.-MHL412
Nov 1983Narrabeen - Float tracking.-MHL412
Dec 1983Narrabeen - Float tracking.-MHL412
Dec 1983Narrabeen - Float tracking.-MHL412
Dec 1983Narrabeen - Float tracking.-MHL412
Aug 1986Narrabeen Lake flood.-MHL488

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
54936s01.pdfIndex plan & tidal planes1:5000856.6kb
54936s02.pdfNarrabeen Lagoon & Mullet Creek1:1000253.6kb
54936s03.pdfNarrabeen Lagoon entrance1:1000425.0kb
54936s04.pdfNarrabeen Lagoon entrance channel1:1000399.7kb
54936s05.pdfNarrabeen Lagoon1:1000775.1kb
54936s06.pdfNarrabeen Lagoon, Deep Creek & Middle Creek1:1000618.1kb
54936s07.pdfNarrabeen Lagoon, Middle Creek & South Creek1:1000394.8kb
54936.txtNarrabeen Lagoon xyz dataN/A501.1kb
Page last updated: 27 April 2012