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Estuaries in NSW

Lake Illawarra
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Minnamurra River Port Hacking
[Image of Estuary] Lake Illawarra
Shape, Size and Scale of Estuary

Estuary Type

Lake

Estuary Characteristics

Area Catchment 270 km2
Waterway Area 36.3 km2
Entrance Characteristics Mostly open and untrained
Location (Lat-Long) 34.544S ,  150.874E
Distance (from Sydney) 90 km South
Summary of Available Data Data Pages

Physical Features

The lake is shallow (0 to 3 m deep) with extensive inter-tidal foreshore. It is poorly flushed. Tidal range in the lake varies up to 0.12 m, the maximum following extreme scour of the inlet. Under average conditions of extensive entrance shoaling, tidal response comprises a discharge of about one million cubic metres producing a range of 0.03 m in the lake. The mean lake super-elevation is 0.3 m above mean sea level - this influences the duration of the ebb and flood tidal components, ie. the ebb duration is 7 to 8 hours and the flood duration, 4.5 to 5.5 hours. Long term average tidal sediment transport rates through the entrance indicate 110,000 m3/yr entering and 30,000 m3/yr leaving the lake system - a further average volume of 80,000 m3/yr is attributed to flood scour (therefore providing a balanced sediment exchange through the entrance). The entrance is heavily shoaled and has a long history of closing especially during prolonged droughts. The Lake Illawarra Authority is currently undertaking works to stabilise the entrance.

Significant Estuarine Tributaries

Lake Illawarra
Mullet Creek
Macquarie Rivulet
Duck Creek

Population and Holiday Centres

Warilla
Windang
Dapto

Special Attributes

General

  • Magnificent natural setting with backdrop of Illawarra escarpment.
  • Important recreational waterway for the Northern Illawarra Region - sailing, water skiing and canoing clubs are well established and amateur fishing and prawning are common near the entrance.
  • Major commercial fish (130 t/yr) and prawn (40 t/yr) producing estuary.
  • Hooka and Goosebery Island in the northern area of the lake comprise the Berkeley Nature Reserve.
  • Major amateur prawning area.

Estuarine Vegetation

The spatial data is reproduced from NSW Fisheries(2006/7) studies, whilst the species makeup is from the West et al.(1985). This map shows the spatial extent of the Estuarine Vegetation.

Type Area Species 1
(km2)
Mangroves 0.000
Seagrass 7.966 z,h,r
Saltmarsh 0.302

References

R.J. Williams, G. West, D. Morrison and R.G. Creese, (2006),
"Estuarine Resources of New South Wales",
prepared for the Comprehensive Coastal Assessment (DoP) by the NSW Department of Primary Industries, Port Stephens.

R.J. West, C.A. Thorogood, T.R. Walford and R.J. Williams. (1985).
"An Estuarine Inventory for New South Wales, Australia".
Fisheries Bulletin 2. Department of Agriculture, New South Wales.

Estuary Commerce

fishing

Management Issues

This estuary falls in the area covered by Southern Rivers Catchment Management Authority.

Lake Illawarra

Current Situation

The Lake Illawarra Authority was established by the Lake Illawarra Authority Act in 1987, with a charter to rehabilitate Lake Illawarra. The Authority pre-dates the Estuary Management Manual (1992) but has followed a similar process in preparing a management plan for Lake Illawarra. An advisory Committee has been created to guide the preparation of the plan.

The Authority is currently undertaking significant environmental restoration works.

The Estuary Management Process 2

Process Status Date
Form Estuary Management Committee (EMC) completed
Assemble Existing Data completed
Carryout Process Study completed
Carryout Estuary Management Study completed
Draft Estuary Management Plan completed
Review Estuary Management Plan completed
Implement Estuary Management Plan commenced
Monitor and Review Estuary Management Process commenced

Contact Details

Lake Illawarra Authority Gary Clarke
Ph (02) 4224 9613 Fax 4224 9651

References

Local Government Areas

Wollongong
Shellharbour

NSW 1:25000 Map Name(s)

Wollongong
Albion Park