Barker Inlet

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The inlet in relation to Adelaide's Central business district
The inlet in relation to Adelaide's Central business district

The Barker Inlet is a tidal inlet of the Gulf St Vincent in Adelaide, South Australia, named after Captain Collet Barker who first sighted it in 1831. It contains one of the southernmost mangrove forests in the world, a dolphin sanctuary, seagrass meadows and is an important fish and shellfish breeding ground. The inlet separates Torrens Island and Garden Island from the mainland to the East and is characterized by a network of tidal creeks, artificially deepened channels, and wide mudflats. The extensive belt of mangroves are bordered by samphire saltmarsh flats and low-lying sand dunes, there are two boardwalks (at Garden Island and St Kilda), and ships graveyards in Broad Creek, Angas Inlet and the North Arm.

The inlet has been adversely impacted since the settlement of South Australia with stormwater and raw sewage discharge, fishing, landfill rubbish dumping, power generation and other activities adversely affecting its flora and fauna. Much of this has changed with the landfill dump on adjacent Garden Island closed in 2000 and remediation work begun.[1] Some stormwater is now being filtered through wetlands before discharge and the inlet has been declared a reserve for the preservation of dolphins, fish, crabs and aquatic plants. The mangroves and waterways are still affected by the adjacent salt crystallization pans, hot wastewater discharge from Torrens Island power station, heavy metal contamination from stormwater and treated sewage, and disturbances from boat traffic.

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[edit] Physical structure

The Inlet is a shallow tidal inlet with a narrow central channel used for boating. Spring tides are over 2½ metres and at low tide much of the inlet is mudflats that are above water level. Most of the creeks through the mangroves drain surrounding land and are not navigable except at high tide by very small boats. There is an artificial channel, running along the side of a breakwater, from a boat ramp at St Kilda near the inlet's north end. The coast side of the mangroves are bounded by extensive salt evaporation ponds leased for industrial usage by the South Australian Government.

Most of the creeks on the eastern side are tidal although Swan Alley creek is the outlet for Dry Creek and the North Arm Creek for the Barker Inlet Wetlands. The wetlands were created in 1994 as part of a stormwater treatment system with both tidal and freshwater sections. There is 1.72 km² of constructed wetlands holding 1.2 Gigalitres of stormwater before discharging via the creek.[2]

[edit] Flora and fauna

The grey mangroves are uniformly of the type Avicennia marina var. resinifera and cover most of the pre-settlement area, but the surrounding samphire salt flats have been greatly reduced in size by changes in the landform with Tecticornia‎ flabelliformis now listed as threatened in the area.[3] The inlet's deeper sections are dominated by Strap or Tape Weed (Posidonia spp.). Eelgrass (Zostera muelleri) and Garweed (Heterozostera tasmanica) dominate the shallows, often being exposed on mudflats at low tide.[4]

A 118 km² Dolphin sanctuary[5] was enacted by the 2005 Adelaide Dolphin Sanctuary Act[6] and covers all of the Barker Inlet and Port River. Bottlenose dolphins are often seen in the inlet, examine and follow small boats and have become a well known tourist attraction. The 20.55 km² St Kilda aquatic reserve covers the entire inlet up to St Kilda and prohibits the taking of crabs shellfish and plants, although line fishing is allowed. The reserve was established for the preservation of the mangroves, seagrass beds and nursery areas for aquatic species notably western king prawns, King George and Yellowfin whiting and blue swimmer crabs.[7] There are many bird species native to the inlet including several species of cormorants, terns, ducks, swans, pelicans, egrets and herons as well as the Seagulls and White-bellied Sea Eagles (Haliaeetus leucogaster). Including migratory birds, over 250 species have been recorded in the inlet, surrounding wetlands and lagoons. Over 70 species of fish have been recorded, along with over 110 of crustaceans and almost 50 of molluscs.[4]

Pelicans on mudflats, Barker Inlet
Pelicans on mudflats, Barker Inlet


[edit] Former uses of the Inlet

From 1906 until 1972 , the inlet's Broad Creek was used as a landing point for explosives that were then transported by a 1½ mile tramway to a magazine at Dry Creek. There are abandoned ships in Broad Creek, Angas Inlet and the north arm of the Port River. The remains of over 30 iron and wooden ships abandoned up until 1945 are now bird roosts and a canoeing attraction. [8]

[edit] References

  1. ^ Thomas, Brett; Fitzpatrick R, Merry R. (July 2001). Literature Review of Acid Sulfate Soils and the environment in the Barker Inlet/ Gillman area. CSIRO Land and Water. Retrieved on 2006-12-26.
  2. ^ A CLEANER FUTURE FOR THE DOLPHINS OF BARKER INLET (media release). Department of the Environment and Heritage (September 21, 2001). Retrieved on 2006-12-26.
  3. ^ Edyvane, K (2000). Ecology. Barker Inlet Port Estuary Committee. Retrieved on 2006-12-26.
  4. ^ a b (2001) The Port River. City of Port Adelaide Enfield, p.4,44. ISBN 0-646-40920-4. 
  5. ^ Adelaide Dolphin Sanctuary, Location and Maps. South Australian Department of Environment and Heritage (2006). Retrieved on 2006-12-26.
  6. ^ ADELAIDE DOLPHIN SANCTUARY ACT 2005. Retrieved on 2006-12-26.
  7. ^ Barker Inlet – St Kilda Aquatic Reserve. South Australian dept of Primary Industries. Retrieved on 2006-12-26.
  8. ^ Port Adelaide Ships' Graveyards. South Australian Department of Environment and Heritage. Retrieved on 2006-12-26.

[edit] External links