Barker Inlet

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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.

1 Physical structure
2 Flora and fauna
3 Former uses of the Inlet
4 References
5 External links

[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 are 172 hectares 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 Halosarcia flabelliformis now listed as threatened in the area. The seagrass meadows are dominated by eelgrass, garweed, and tapeweed.^[3]

A 118km² Dolphin sanctuary^[4] was enacted by the 2005 Adelaide Dolphin Sanctuary Act^[5] 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 2055 hectare 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 yellow fin whiting and blue swimmer crabs.^[6] 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 ubiquitous Seagull.

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. ^[7]