The Trinity Inlet is an oceanic

inlet An inlet is a (usually long and narrow) indentation of a shoreline, such as a small arm, bay, sound, fjord, lagoon or marsh, that leads to an enclosed larger body of water such as a lake, estuary, gulf or marginal sea. Overview In marine geogra ...

which serves as the

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Ham ...

for the city of

Cairns Cairns (, ) is a city in Queensland, Australia, on the tropical north east coast of Far North Queensland. The population in June 2019 was 153,952, having grown on average 1.02% annually over the preceding five years. The city is the 5th-most-p ...

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. The city centre is on the western bank where the inlet meets the

Coral Sea The Coral Sea () is a marginal sea of the South Pacific off the northeast coast of Australia, and classified as an interim Australian bioregion. The Coral Sea extends down the Australian northeast coast. Most of it is protected by the Fre ...

Location and features

The Trinity Inlet is located in the original delta of the

Mulgrave River The Mulgrave River, incorporating the East Mulgrave River and the West Mulgrave River, is a river system located in Far North Queensland, Australia. The -long river flows towards the Coral Sea and is located approximately south of . Location ...

, which since the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

flows to a mouth further south. This is because

Volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

activity which resulted in the rise of Green Hill near the Mulgrave Valley, did not block the river, as sediments from more local streams continued to build up over the volcanic rocks. The Mulgrave River enters the sea at Russell Heads, approximately 30 km south of Trinity Inlet. It is unlikely that a river would shift its course and add a further 30km to its length before entering the sea. This is because the river would then adopt a shallower gradient and lose efficiency in transporting sediment. Rivers in this region do occasionally shift course (such as the Barron River in the 1930s) but this is usually to adopt a shorter course to the sea and gain a steeper gradient otherwise known as a gradient advantage. Trinity Inlet is lined with

mangrove A mangrove is a shrub or tree that grows in coastal saline water, saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evoluti ...

s and mudflats. Within the inlet a large mud island has been formed and was given the name Admiralty Island. Concerns have been raised about the amount of debris and derelict shipping that exist in the upper regions of the inlet. Commercially the inlet provides a limited deep-water berthing for the port of Cairns, allowing the export of

cane sugar Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula . For human consumption, sucrose is extracted and refined ...

. The region's only tanker berth and the Royal Australian Navy base HMAS ''Cairns'' are located on the inlet. Several shipbuilders and tour operators that visit the

Great Barrier Reef The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, ...

operate from the Reef Terminal on the entrance to the inlet. Remnants of a

levee A levee (), dike (American English), dyke (English in the Commonwealth of Nations, Commonwealth English), embankment, floodbank, or stop bank is a structure that is usually soil, earthen and that often runs parallel (geometry), parallel to ...

can be found on the eastern bank opposite Cairns. This was an effort by CSR in the 1970s to cultivate sugar cane on mostly intertidal land previously occupied by mangroves and saltmarsh. This was not successful due to the disturbance of a large area of acid sulfate soil. Discharge of sulfuric acid into Trinity inlet from this land resulted in a number of fish kills. In recent years, the Queensland Government has undertaken a major remediation project to prevent the acid discharge and rehabilitate the land behind the levee. The inlet offers shelter to small vessels when

tropical cyclones A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depend ...

threaten. A commercial

saltwater crocodile The saltwater crocodile (''Crocodylus porosus'') is a crocodilian native to saltwater habitats and brackish wetlands from India's east coast across Southeast Asia and the Sundaic region to northern Australia and Micronesia. It has been listed ...

farm is in operation on the upper reaches, though wild examples are still very rare in the area after hunting in the early 20th century. This area is sacred to the Indigenous Yidinji peoples of gimuy for its rich cultural stories including (but not limited to) Kuyala the Sea Eagle.

References

{{reflist Bays of Queensland Cairns, Queensland Inlets of Australia

Location and features

See also

References