Directory of Important Wetlands

Directory of Important Wetlands in Australia - Information sheet

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Barker Inlet & St Kilda - SA005

Level of importance: National - Directory
Location: 34 degrees 47' S, 138 degrees 32' E; Fleurieu Peninsula, located along the eastern shore of Gulf St Vincent and encompasses the coastal waters, fringing mangroves and adjoining salt fields of the Barker Inlet, extending from St Kilda to Outer Harbour. Situated 15 km north west of the city of Adelaide, and 4 km north of Port Adelaide.
Biogeographic region: Eyre and Yorke Blocks.
Area: No information.
Elevation: Sea level.
Other listed wetlands in same aggregation: SA015.
Wetland type: A1, A2, A6, C4, A8, A9, A7
Criteria for inclusion: 1, 2, 3, 5, 6,
Site description:
The shoreline has wide tidal mud flats and an extensive belt of mangroves fringing the samphire salt flats and low-lying dunes of the coastal plain. Within the Barker Inlet lies Torrens Island and Garden Island which are surrounded on either side by the Port Adelaide River and Torrens Reach. Along the eastern shore of the Gulf, several creeks feed into the Inlet including Chapman Creek, Swan Alley Creek, Broad Creek and North Arm Creek. Freshwater is contributed by stormwater drainage and the Little Para River which opens into the inlet as Swan Alley Creek. Extensive salt evaporation ponds occur adjacent to most of the mangrove and samphire areas.
Physical features:
Landform: Mangrove woodlands, inter and supra tidal flats, subtidal seagrass meadows, tidal channels, estuarine mud flats and swamps, dunes and chenier ridges. Geology: Comprise marine sands and muds of Holocene age (Semaphore Sands and St Kilda Formation) which overlie older Pleistocene clays (Pooraka and Hindmarsh Formations) and in parts a marine calcarenite (Glanville Formation). Soils: Tidal flats comprise fluvial mud and marine sands; dunes are of quartz sands. Climate: Mean annual rainfall is c. 470 mm, mainly falling in May-September; annual evaporation is c. 1750 mm.
Hydrological features:
Water supply: Southern Ocean - tides are semi-diurnal to mixed tides with two low and two high waters at springs to virtual cancellations at neap tides (Fotheringham 1994). Water depth: Highest sea level recorded at Outer Harbour is 3.98 m (2.317 m AHD), July 1981.
Ecological features:
Ecological role: The Inlet and adjoining mangrove creeks serve as important nursery areas for a number of important commercial and recreational marine fish and crustacean species. The variety of coastal habitats provide roosting, sheltering and feeding grounds for a large number of waterbirds and provide early spring to late summer refuge for many migratory waders. The area also provides significant breeding habitats for pelicans, cormorants, oystercatchers, gulls, terns, egrets and herons. Plant structural formations: Mangrove low woodland fringe the coast and are backed by saltmarsh communities; dune and chenier habitats support low woodland to open low scrub.
A good example of extensive mangrove and saltmarsh communities in the Gulf St Vincent. It is also the largest area of mangroves in the Gulf. The proximity of this mangrove stand to Adelaide is an important feature, there being few other similar stands in a major city in Australia.
Notable flora:
Threatened species: Halosarcia flabelliformis (Nv, Sv) and Centrolepis cephaloformis (Sr). Composition: Extensive mud and sand flats colonised by the seagrasses Posidonia sp., Zostera muelleri and Heterozostera tasmanica; Avicennia marina var. resinifera low woodland occupies the intertidal zone and extends up to 2 km wide; saltmarsh communities dominated by Sclerostegia arbuscula and Sarcocornia quinqueflora abut the mangroves in areas that are regularly inundated by tides; a low chenopod shrubland of Maireana oppositifolia and Atriplex paludosa, interspersed with Sclerostegia arbuscula and Lawrencia squamata occurs on the higher parts of the saltmarsh, chenier and beach ridges, dunes and levee banks; Halosarcia halocnemoides and H. flabelliformis low heath to open scrub is largely confined to salt scalds; freshwater swamps of tall sedgelands, Bolboschoenus caldwellii and Phragmites australis occur at the Little Para River outlet; dunes and chenier ridges on Torrens Island support a variety of species including Acacia ligulata, Acacia pycnantha, and Nitraria billardierei (Ferguson 1986; Fotheringham 1994).
Notable fauna:
Threatened species: White-bellied Sea-Eagle Haliaeetus leucogaster (Sv), Little Egret Egretta garzetta (Sv), Slender-billed Thornbill Acanthiza iredalei rosinae (Sv). Composition: c. 57 waterbird species recorded; 12 listed under treaties. Breeding: 18 species found breeding. A colony of 600 Pied Cormorants Phalacrocorax varius breed in mangroves in a lagoon of the nearby salt fields; the Little Pied Cormorant Phalacrocorax melanoleucos, Australian Pelican Pelecanus conspicillatus (c. 100), Little Egret, Nankeen Night Heron Nycticorax caledonicus, Silver Gull Larus novaehollandiae (300 000), Caspian Tern Sterna caspia and Crested Tern Sterna bergii breed on islets off Torrens Island and Outer Harbour; breeding waterfowl include the Australian Shelduck Tadorna tadornoides and Chestnut Teal Anas castanea; Pied Oystercatchers Haematopus longirostris nest on the sandy beaches and spits about Torrens Island and Outer Harbour; Black-winged Stilts Himantopus himantopus commonly breed on samphire flats. Migration stop-over: Eight species of migrant shorebird occur, the most common species during the summer months include the Red-necked Stint Calidris ruficollis, Sharp- tailed Sandpiper C. acuminata, Curlew Sandpiper C. ferruginea, Common Greenshank Tringa nebularia, Marsh Sandpiper T. stagnatilis, and Black-tailed Godwit Limosa limosa (Ferguson 1986; Cox 1990; Australasian Wader Study Group counts 1993a unpub. records; Goonan 1993).
Other Fauna:
Fishes: 74 species of fish recorded; the fish and crustacean species that utilise the Barket Inlet as mainly a nursery area include the Southern Sea Garfish Hyporhampus melanochir, Yellow-eye Mullet Aldrichetta forsteri, King George Whiting Sillaginodes punctata, Western Sand Whiting Sillago schomburgkii, Blue Swimmer Crab Portunus pelagicus and Western King Prawn Penaeus latisulcatus. Most of these species, including the Jumper Mullet Liza argentea and Black Bream Acanthopagrus butcheri, also use the area as spawning and feeding areas. Other species, hardyheads, gobies and Striped Perch Pelates sexlineatus occur in large numbers in the area. Mammals: Records of the Leopard Seal Hydrurga leptonyx, Common Dolphin Delphinus delphis, Blue Whale Balaenoptera musculus (Ne, Se) and Short-finned Pilot Whale Globicephala macrorhynchus (Sr) in the vicinity of Pt Adelaide, Outer Harbour and St Kilda.
Social and Cultural values:
Cultural: The Greenfields Archaeological and Burial Site is located on the floodplain of Dry Creek adjacent to the salt fields and was traditionally used as a regular camping area by the Kaurna people. Excavations have uncovered stone artefacts, food remains (i.e. animal skeletal material) and burial sites. Research/education: The Inlet is a popular area for research into pollution, mangroves and fish ecology. The St Kilda visitor centre and the mangrove boardwalk are exceptional educational facilities. The St Kilda boardwalk winds through dense mangroves for 1.7 km and is one of the few in the world where people are able to come into close contact with a mangrove ecosystem. Recreation: Popular recreational activities include fishing, boating, power boat racing, canoeing, waterskiing and bird watching - the area is regularly visited by overseas ornithologists and has become a bird observation area of interstate and international renown. Permanent coastal mooring facilities for commercial and recreational craft at St Kilda, Garden Island, North Arm and Port Adelaide. Outer Harbour and Port Adelaide are major ports for international and national ships (Jones 1984; Ferguson 1986; Goonan 1993).
Land tenure:
Crown land - northern tip of Torrens Island is a Conservation Park, St Kilda-Chapman Creek (870 ha) and Barker Inlet-St Kilda (2055 ha) are Aquatic Reserves. Private land.
Current land use:
Nature conservation, commercial and recreational fishing, boating, light industry, landfill operations at Garden Island, salt production and power generation at Torrens Island Power Station. The Multi-Function Polis site at Gillman and Dry Creek include the development of man-made wetland areas using stormwater run-off from adjacent areas, light industry and high human population.
Disturbance or threat:
Past/present: Effluents are discharged into the Inlet from the Torrens Island Power Station, Port Adelaide Sewage Treatment Works, the Little Para River and several stormwater drains. Construction of causeways associated with electricity transmission lines and embankments have caused disruptions to tidal movements and has led to mangrove dieback. Illegal netting, rubbish dumping, weed infestation, grazing by rabbits and English Fallow Deer, extensive trampling and damage of trees near Garden Island boat ramp. Large accumulations of drifting cabbage weed Ulva lactuta seem to cause mangrove deaths in areas north of St Kilda, mangrove death also caused by boat wash.

Potential: An increase in the discharge of effluents into the Inlet, plans to close and/or relocate the salt fields north to Port Parham and projected rise in sea level.
Conservation measures taken:
The Port River Mouth and the Penrice salt fields have been identified as areas of international importance for shorebirds by Watkins (1993).
Management authority and jurisdiction:
Torrens Island Conservation Park is managed by DENR. District office located at Salisbury. The Aquatic Reserves are managed by the S.A. Department of Fisheries. Torrens Island Power Station is managed by ETSA Corporation. Penrice Soda Products Pty Ltd manage the salt fields and hold salt mining leases. The St Kilda board walk and visitor centre is managed by the City of Salisbury.
See SA Reference List
Compiler & date:
J. Morelli, S. A. Department of Environment and Natural Resources, 1995.
AWRC Division: South Australian Gulf
AWRC Region:
AWRC Basin: