Lake Alexandrina (South Australia)

from Wikipedia, the free encyclopedia
Lake Alexandrina
LowerLakes2004.jpg
Lake Alexandrina is the larger of the Lower Lakes
Geographical location South Australia
Tributaries Murray River , Bremer River , Angas River , Finniss River
Drain Murray estuary
Islands Hindmarsh Island, Mundoo Island, Long Island, Ewe Island, Reedy Island, Mud Island, Tauwitchere Island, Pomanda Island
Places on the shore Milang, Goolwa
Data
Coordinates 35 ° 25 ′ 0 ″  S , 139 ° 7 ′ 0 ″  E Coordinates: 35 ° 25 ′ 0 ″  S , 139 ° 7 ′ 0 ″  E
Lake Alexandrina (South Australia) (South Australia)
Lake Alexandrina (South Australia)
Altitude above sea level f10.75 m
surface 649 km²dep1
length 38.4 kmdep1
width 20.6 kmdep1
volume 1.61 km³dep1
Maximum depth 5 m
Middle deep 2.8 m
Catchment area 1,061,469 km²
Template: Infobox Lake / Maintenance / EVIDENCE AREA Template: Infobox Lake / Maintenance / EVIDENCE LAKE WIDTH Template: Infobox Lake / Maintenance / EVIDENCE VOLUME Template: Infobox Lake / Maintenance / EVIDENCE MAX DEPTH Template: Infobox Lake / Maintenance / EVIDENCE -MED-DEEP template: Infobox See / Maintenance / DETECTED Catchment Area

The Lake Alexandrina is a lake in the southern Australian state of South Australia . It is located about 100 km southeast of Adelaide and is connected to the Indian Ocean .

Lake Alexandrina is north of Encounter Bay and east of the Fleurieu Peninsula . The Murray River is the largest river that flows into the lake. There is also the Bremer River , the Angas River and the Finniss River . All of these rivers have their source on the eastern slopes of the southern Mount Lofty Ranges . The lake is shallow and there are many islands at its southwest end.

In the city of Goolwa , Lake Alexandrina is connected to the ocean; this point is known as the Murray Estuary . However, when the water flow in the rivers is low, this connection is closed with a sandbank. The tide and southwest storms used to push seawater into the lake. Today, however, only fresh water remains in Lake Alexandrina because a series of flood weirs, the Goolwa Barrages , were built between the islands at the Murray Estuary. The lake needs an annual influx of at least 1 billion m³ of water to compensate for the evaporation losses.

Although the lake was connected to the sea, fresh and salt water almost did not mix; 95% of the time it contained only fresh water. The influx of salt water from the sea led to little lateral and longitudinal mixing. Hindmarsh Island (east of Goolwa) is considered the largest island in the world with fresh water on one side and salt water on the other. Lake Alexandrina is connected to the smaller Lake Albert on the southeast side by a small canal .

The lake was named after the future Queen Victoria , niece and successor of King Wilhelm IV , who was called Princess Alexandrina in her youth . After the coronation of Victoria, there were some voices suggesting that the lake be renamed Lake Victoria , but this idea failed to take hold.

In Aboriginal myths , the lake is inhabited by a monster named Muldjewangk .

Lake Alexandrina is home to a number of water birds, including some migratory bird species from the northern hemisphere. Pelicans , black swans, and a host of other birds make their living from the insects, plants, and water of the lake. For example, these are wrens , garden fan tails , swallows and ravens . Birds of prey, such as eagles and hawks , can often be seen above the water and the adjacent bank areas. Turtles live in the lake, lizards and snakes can be found on the shore.

Common insect species include dragonflies , a range of moths and butterflies, and large numbers of beetles . There are also freshwater fish, such as carp, in the lake . The soil around the lake is poor in organic carbon, but barley and other grains grow well there. Dry soils are found on the southeastern shores of Lake Albert and in certain areas around Lake Alexandrina.

In 2008 the water levels in Lake Alexandrina and Lake Albert sank so far that large amounts of sulfuric acid earth formed. The soils at the bottom of the lake are usually rich in natural iron sulfide. If they are exposed to the air supply, as can happen during periods of great drought, the sulphides are oxidized and sulfuric acid is formed . Today, the flood weirs prevent the ingress of seawater, which has stopped this process in every drought since the Ice Age. It has been proposed to build a weir at Pomanda Island to protect the upstream drinking water supply in the event that it becomes necessary to open the flood weirs.

The journalist Edward Wilson , who visited the lake in the 1850s, described it as follows:

“Lake Alexandrina is the most beautiful freshwater lake I have ever seen. It really looked so wonderful when a stiff breeze came up, creating waves that could make you seasick, so I could hardly believe it was a freshwater lake. But this is exactly the case. It is forty or fifty miles long, about twelve or fifteen miles wide, and its shores faded into the distance until they became utterly invisible, the way we only know it from the sea. The lake is almost entirely fed by the Murray and so remains the swampy pond I was talking about, and unfortunately that distracts from the otherwise wonderful appearances of this wonderful body of water. "

Individual evidence

  1. ^ A b c d Steve Parish: Australian Touring Atlas . Steve Parish Publishing. Archerfield QLD (2007). ISBN 978-1-74193-232-4
  2. ^ A b c d e The Facts the Lower Murray Lakes and Coorong. Rfcssa.org.au ( Memento from February 18, 2011 in the Internet Archive ) (PDF; 1.4 MB)
  3. Alexandrina, Lake . Place Names in South Australia. State Library of South Australia
  4. ^ Fire, Flood and Acid Mud. Catalyst, May 1, 2008, archived from the original on April 30, 2008 .;
  5. ^ Edward Wilson: Rambles at the Antipodes: A Series of Sketches of Moreton Bay, New Zealand, the Murray River and South Australia and the Overland Route. With 2 maps, and 12 tinted lithographs, illustrative of Australian life . WH Smith (1859). P. 45