Lake Bosumtwi

Infobox lake
lake_name = Lake Bosumtwi
image_lake = Bosumtwi Worldwind SW.jpg
caption_lake =
image_bathymetry =
caption_bathymetry =
location = Ghana
coords = coord|6|30.3|N|1|24.5|W|region:GH-AH_type:waterbody_scale:100000|display=inline,title
type = impact crater lake
inflow = rainfall
outflow = none
catchment = 400 km²
basin_countries = Ghana
length = 8.6 km (5.3 mi)
width = 8.1 km (5.0 mi)
area = 49 km² (19 mi²)
depth = 45 m (150 ft)
max-depth = 81 m (265 ft)
volume =
residence_time =
shore =
elevation = 150 m (490 ft)
islands =
cities =
reference = [http://www.worldlakes.org/lakedetails.asp?lakeid=10252 Bosumtwi] . "LakeNet". Retrieved on 2007-02-18.]

Lake Bosumtwi, situated within an ancient meteorite impact crater, is approximately 8 km across and the only natural lake in Ghana. It is situated about 30 km south-east of Kumasi and is a popular recreational area. There are about 30 villages near the lake, with a combined population of about 70,000 people.

The Ashanti consider Bosumtwi a sacred lake. According to traditional belief, the souls of the dead come here to bid farewell to the god Twi. Because of this, it is considered permissible to fish in the lake only from wooden planks.

Impact crater

The Lake Bosumtwi impact crater is 10.5 km in diameter, slightly larger than the present lake, and is estimated to be 1.07 million years old (Pleistocene period). [http://www.unb.ca/passc/ImpactDatabase/images/bosumtwi.htm Bosumtwi] . "Earth Impact Database". Retrieved on 2007-02-18.] cite journal
author = Koeberl, C.
coauthors = Milkereit, B.; Overpeck, J.T.; Scholz, C.A.; Amoako, P.Y.O.; Boamah, D.; Danuor, S.; Karp, T.; Kueck, J.; Hecky, R.E.; Others,
year = 2007
title = An international and multidisciplinary drilling project into a young complex impact structure: The 2004 ICDP Bosumtwi Crater Drilling Project—An overview
journal = Meteoritics & Planetary Science
volume = 42
pages = 483–511
url = http://www.ingentaconnect.com/content/arizona/maps/2007/00000042/F0020004/art00002
accessdate = 2007-10-07]

The crater has been partly eroded, and is situated in dense rainforest, making it difficult to study and confirm its origin by meteorite impact. Shock features such as shatter cones are largely overgrown by vegetation or covered by the lake. However, drilling of the crater's central uplift beneath the lake floor has recently provided an abundance of shocked materials for scientific study. ] Tektites, believed to be from this impact, are found in the neighbouring country of Ivory Coast, and related microtektites have been found in deep sea sediments west of the African continent. ]

Climate history

Before the crater hit, there was a lush rainforest filled with animals. The crater opened up a hole in the ground which filled with water, so now there is a lake.cite web
url=http://news.bbc.co.uk/2/hi/science/nature/3736040.stm
title=BBC NEWS | Science/Nature | Drilling for Africa's climate history
publisher=news.bbc.co.uk
accessdate=2008-03-16
last=Peace
first=Roland]

Periods of heavy rainfall filled the crater with water, causing the lake level to rise above the lowest points of the rim. Such periods are evidenced from fossils of fish found on hilltops. Water even flowed from the basin through an overflow channel. However, there were also times when the water level was so low that the rainforest entered the basin rendering the lake only a small pond. Such a period, according to legend, lasted until about 300 years ago.

Human history

The legends say that in 1648 an Ashanti hunter named Akora Bompe from the city of Asaman was chasing an injured antelope through the rainforest. Suddenly, the animal disappeared in a small pond. It was as if this body of water wanted to save the animal's life. The hunter never got the antelope, though he settled close to the water and started catching fish. This place he named “Bosomtwe”, meaning “good antelope”. This story suggests that at that time the lake level was very low. The large dead trees standing offshore in the lake also evidence this, for they are over 300 years old.

The following centuries saw several wars about the lake as both the Ashanti and the Akim clashed, each claiming the area. The Ashanti prevailed.

Each village in the lake area has its own shrine or fetish grove. With the arrival of Christianity, some of people gave up former beliefs, though many continue to seek traditional help in bad times or against diseases.

The Abrodwum Stone is held to be the spiritual centre of the lake. Here, when there is such poor fishing it is considered a bad omen, the lake people sacrifice a cow. This act is celebrated in the presence of his majesty, the Ashanti king, the Asantehene himself. In the ceremony, the cow's innards are given to the stone and the rest is thrown into the lake. The crowd rushes into the water with cutlasses and axes to take their share of the meat. This is an event very much worth seeing. However, as such an omen depends on various factors, it is hardly predictable.

There is a traditional taboo against touching the water with iron and modern boats are not considered appropriate. The padua, a wooden plank requiring considerable skill to maneuver, is the legitimate method.

There are current environmental concerns, including overfishing and inadequate farming methods.The growing population increased demand for fish. Excessive fishing led to steadily decreasing catches, forcing increased reliance on agriculture. As more and more of the hills are converted into farmland, exposing the surface to the heavy rainfalls, soil erosion becomes an ever greater problem.In addition there is the changing lake level. Many villages have been submerged several times forcing the people to move up the slopes or outside the basin. That is the origin of such double names as Pipie No.1 and Pipie No.2 (see map on http://people.freenet.de/bosomtwe).

The lake is a popular resort area with local people for swimming, fishing and boat trips.

The village of Amakom has a clinic called Lake Bosumtwi Methodist Clinic, served by boat and vehicle.

References

*cite journal|journal=Geology|year=1998|volume=26|issue=6|pages=543–546|title=Detailed structural analysis of the rim of a large, complex impact crater; Bosumtwi Crater, Ghana|author =Wolf U. Reimold, Dion Brandt, and Christian Koeberl|doi=10.1130/0091-7613(1998)026<0543:DSAOTR>2.3.CO;2

External links

* [http://www.freenet-homepage.de/bosomtwe Lake Bosomtwe Ecotourism Map and Guide (notice: "Bosomtwe" is the correct spelling according to Kumasi University)]
* [http://www.icdp-online.de/sites/bosumtwi/index/index.html Lake Bosomtwe Drilling Project]
* [http://www.geocities.com/lakebosomtwe Friends of Lake Bosomtwe NGO Informational Website]