Alligator Rivers

from Wikipedia, the free encyclopedia
East Alligator River
Cahills Crossing on the East Alligator River, before 2008

Cahills Crossing on the East Alligator River, before 2008

Data
location Northern Territory , Australia
River system East Alligator River
Drain over East Alligator River  → Van Diemen Gulf
source at Central Arnhem Plateau Weather Station
13 ° 17 ′ 36 ″  S , 133 ° 13 ′ 13 ″  E
Source height 343  m
muzzle Van Diemen Golf at Point Farewell Coordinates: 12 ° 4 ′ 56 "  S , 132 ° 35 ′ 41"  E 12 ° 4 ′ 56 "  S , 132 ° 35 ′ 41"  E
Mouth height 0  m
Height difference 343 m
Bottom slope 1.5 ‰
length 227 km
Right tributaries Tin Camp Creek, Cooper Creek
Communities Ubirr
South Alligator River
location Northern Territory , Australia
River system South Alligator River
Drain over South Alligator River  → Van Diemen Gulf
source south of Big Sunday (in the southern part of Kakadu National Park )
13 ° 45 ′ 48 ″  S , 132 ° 38 ′ 33 ″  E
Source height 235  m
muzzle Van Diemen Gulf across from Field Island
12 ° 11 ′ 59 ″  S , 132 ° 23 ′ 24 ″  E
Mouth height 0  m
Height difference 235 m
Bottom slope 0.87 ‰
length 269 ​​km
Left tributaries Dinner Creek, Kurrundie Creek, Motor Car Creek, Kambolgie Creek, Gundjulmarrke Creek, Coirwong Creek
Right tributaries Koolpin Creek, Coronation Creek, Fisher Creek, Stag Creek, Waterfall Creek, Barramundie Creek, Nourlangie Creek, Jim Jim Creek, Obiworrbie Brook
Communities Gimbat, El Sherena, Aurora Cockatoo
West Alligator River
Marangarrayu
location Northern Territory , Australia
River system West Alligator River
Drain over West Alligator River  → Van Diemen Gulf
source north of Gumbumbuk
12 ° 59 '26 "  S , 132 ° 8' 47"  O
Source height 46.7  m
muzzle Van Diemen Golf at West Alligator Head
12 ° 13 ′ 20 ″  S , 132 ° 16 ′ 58 ″  E
Mouth height 0  m
Height difference 46.7 m
Bottom slope 0.41 ‰
length 115 km
Left tributaries Orange Creek

The Alligator Rivers are three rivers in the north of the Australian Northern Territory . Specifically, these are the East Alligator River , the South Alligator River and the West Alligator River . Instead of alligators , however, real crocodiles live there .

region

At the same time, the region around these rivers, which is part of the Arnhem Land , also bears this name. It is one of the most biodiverse regions in Australia, which also includes parts of the Kakadu National Park , and at the same time an Important Bird Area (IBA) east of the IBA in the floodplains of the Adelaide River and the Mary River . The region also has significant mineral deposits, particularly uranium ore ; the Ranger uranium mine is there. There is also a rich Aboriginal cultural heritage . There are 1,500 sites in the region.

Rivers

All three rivers have long estuaries on whose banks mangrove swamps have formed. These and the river meadows have developed over the past 20,000 years.

East Alligator River

It rises in the northern part of the Anrhemland plateau and flows north and then northwest through great canyons. Its lower course runs along the northeast border of the Kakadu National Park and it flows into the Van Diemen Gulf at Point Farewell .

Tributaries with mouth heights

  • Tin Camp Creek - 8 m
  • Cooper Creek - 0 m

South Alligator River

The river has its source north of Mount Stow in the southern part of Kakadu National Park. It runs through the center of the park to its northern end, where it also flows into the Van Diemen Gulf. It crosses under the Kakadu Highway , the Old Jim Jim Road and the Arnhem Highway . There are many abandoned uranium mines in its valley, which were opened between 1955 and 1965. There are many spectacular waterfalls on the river and its tributaries, e.g. B. Jim Jim Falls on Jim Jim Creek and the Twin Falls on its tributary Twin Falls Creek .

Tributaries with mouth heights

West Alligator River

The shortest of the three rivers has its source in the western part of Kakadu National Park and, like the South Alligator River, runs its entire length in the park. Its course leads north, where it flows a little west of the South Alligator River, at West Alligator Head , into the Van Diemen Gulf. He also passes under the Arnhem Highway.

Tributaries with mouth heights

  • Orange Creek - 8 m

climate

Waterfall in Kakadu National Park after a downpour

Like most of northern Australia, the Alligator Rivers region has a monsoon climate . The dry season lasts from May to September and the rainy season from November to March. April and October are months of transition between the two seasons. The annual rainfall in Jabiru is around 1,540 mm, of which almost all of the rain falls in the rainy season. In the rainy season the prevailing wind direction is west to northwest, in the dry season east to southeast.

The three rivers carry water all year round, even in the dry season. The same goes for the Wildman River , which runs just west of the West Alligator River. All tributaries of these rivers, however, dry up in parts during this time. The land dries up and the game gathers around the permanent water sources such as rivers, springs and water holes. The length of the drought depends on the amount of rain that fell in the previous rainy season. In normal years, the tributaries carry water again continuously from around mid-December and dry up again at the end of June. If the rains were very heavy, the times shift to November or August.

In the rainy season, the savannah turns green, the wild animals swarm out, the birds return and the watercourses spread out to the areas near the shore and turn them into swamps. The floodplains are covered with silt when they slowly dry out in the dry season.

In the rainy season the water temperature is higher and the watercourses are less turbulent. Turbulence increases in the dry season, especially in shallow watercourses.

The Alligator Rivers region has frequent cyclones from October to May , as is the case in other regions of northern Australia and Southeast Asia.

Wildlife

Saltwater crocodile in Kakadu National Park

The region was named after the crocodiles in the lower reaches of the rivers. But it offers habitats for a wide range of plant and animal life. More than 1,500 plant species have been counted in a range of tropical habitats, from mangrove swamps to monsoon forests to tropical savannah and woodland. There are 46 species of fish in the river systems, representing about a quarter of all known species in Australia.

The area also has a large population of rats ( Rattus colletti ) and their predators, the water pythons . New vertebrate species are still being discovered there, such as: B. the cockatoo-narrow-foot pouch mouse and the Australian cockatoo pebble mouse ( Pseudomys calabyi ). The potential of discovering previously unknown invertebrate species such as B. ants, is even bigger.

There is a connection between the ecosystems and the introduced flora and fauna. Introduced plant species such as the giant mimosa and the mission grass damage the habitats. Introduced species such as the released water buffalo and cane toad also cause problems.

Birds

The floodplains of the Alligator Rivers are of worldwide importance for the moth geese population

There are many bird species in the region, making up a third of all bird species in Australia. Especially on the rivers of the region there are waterfowl, such as the cracked goose , ducks , herons , ibises and spoonbills . The floodplain forests of the Alligator Rivers form an important bird area of ​​383,000 hectares, on which about 5 million water birds live. a. over 1% of the world population of 22 species, a substantial number of three almost endangered species and 11 species that occur only in small numbers or in the savannah in small numbers.

Aboriginal heritage

The Aborigines lived in the Alligator Rivers region for 50,000 years. Therefore, the area has a rich cultural heritage of cave paintings and rock carvings in over 1,500 locations. Many Aboriginal artifacts were found in old campsites in the region.

In the southern part of Kakadu National Park there are a number of sites with artifacts depicting the god Bula . These places are considered both sacred and dangerous by the Aborigines because of this association. There are also connections to Macassar traders and Europeans there.

At Ubirr Rock at Cahill's Crossing on the East Alligator River, there are paintings from 20,000 years ago of figures throwing spears and wearing headgear to the first contact with European settlements.

The Gagudju live in the area between the East Alligator River and the South Alligator River. They share responsibility for the part of Kakadu National Park on their land with the Australian authorities. Gunbalany (formerly: Oenpelli ), a settlement in the area, is administered by Aboriginal people and is an important center for their arts and crafts. The Gagadju language is no longer widely spoken today, even if this was the case until the beginning of the 20th century.

The Jawoyn live in the area around the South Alligator River and the southern Mary River , as well as in the area around Katherine . In 1993 they negotiated a contract to use the Coronation Hill Uranium Mine . This uranium mine may continue to be exploited. In return, Jawoyn are employed and trained and are also accepted as business partners.

The Gunwinggu live in the area between the Liverpool River and the East Alligator River. Their traditional beliefs remain important to them; the ngalyod , the rainbow serpent, plays an important role in their art and tradition. The Gunwinggu have received royalties from the Nabarlek uranium mine in recent years. They live in Gunbalany and Maningrida .

History of European Settlement

discovery

The explorer Phillip Parker King was the first English skipper to enter the Gulf of Carpentaria . Between 1818 and 1822 he undertook several research trips in the area and named the rivers after the crocodiles, which he mistakenly believed to be alligators .

"On our course up and down the river, we encountered several very large alligators and some were noticed sleeping on the mud. This was the first time we had seen these animals, excepting that at Goulburn Island, and, as they appeared to be very numerous and large, it was not thought safe to stop all night up the River. " “On our journey upriver and downriver we encountered some very large alligators and we noticed some asleep in the mud. This was the first time, with the exception of Goulburn Island, that we had seen these animals and, since they seemed very numerous and very large to us, we thought it unsafe to stop up by the river all night. "

Ludwig Leichhardt was the first European explorer to visit the area in 1845 on his way to Port Essington . Leichhardt followed a stream down from the rocky steps of Arnhem Land and crossed the East Alligator River and the South Alligator River. John McDouall Stuart visited the area in 1862.

Branches

The Europeans settled in this area very late and only sporadically because it was very remote and diseases were also a problem. Commercial exploitation of the fur and horns of the water buffalo began in the 1880s. Paddy Cahill , who came to the area to set up a cattle breeding station, was the first buffalo hunter there. Buffalo economic exploitation lasted about 70 years until synthetic replacements were developed in the late 1950s. Crocodile hunting was also widespread until the hunt for freshwater crocodiles was banned in 1964. The hunting ban for saltwater crocodiles followed in 1971.

Paddy Cahill built a cattle breeding station at Oenpelli in 1906 and in 1913 it was self-sufficient. And indeed, Cahill's success in Oenpelli was seen as a reason for others to do the same. Further stations were set up, but were often not equally successful. Goodparla , a cattle and buffalo station, operated with mixed success until the Australian government bought the land to create Kakadu National Park.

Missionaries provided Aboriginal education for most of the 20th century. The Kapalga Native Industrial Mission was founded near the South Alligator River in 1899, but only existed for four years. In 1925 the Church Mission Society built a mission station in Oenpelli that operated for 45 years. In 1975 an Aboriginal city council took over the administration of the Oenpelli settlement.

Gold digging began on a small scale in Imarlkba on Barramundi Creek in the 1920s and in Moline in the 1930s . It was not until the discovery of uranium ore in the mouth of the South Alligator River in 1953 that a mining industry was established. In 1957 there were already 13 uranium mines employing 150 workers, including those on Coronation Hill . After the discovery of large uranium ore deposits in Jabiluka , Ranger and Koongarra , the federal government set up the Ranger Uranium Environmental Inquiry (also known as Fox Inquiry ), which took care of the development of the mine in Ranger and the other two locations and established Jabiru as a supply center. The Aborigines received royalties to compensate for the loss of their land.

Web links

Commons : Alligator Rivers  - Collection of images, videos and audio files

swell

  • Alex Barlow & Marji Hill (editors): Encyclopedia of Australia's Aboriginal People . Macmillan Education Australia (2000)

Individual evidence

  1. ^ A b c d Map of East Alligator River, NT . Bonzle.com
  2. ^ A b c d Map of South Alligator River, NT . Bonzle.com
  3. ^ A b c d Map of Marangarrayu (West Alligator River), NT . Bonzle.com
  4. ↑ IBA: Alligator Rivers Floodplains . In: Birdata . Birds Australia. Retrieved May 19, 2011.
  5. ^ Lieutenant Phillip Parker King: Narrative of a Survey of the intertropical and western coasts of Australia . Entry created in 1826 for May 6, 1818. Quoted in: Webster World (October 23, 2005)