Lake Bosumtwi
From Wikipedia, the free encyclopedia
| Lake Bosumtwi | |
|---|---|
 |
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| Location | Ghana |
| Coordinates | |
| Lake type | impact crater lake |
| Primary sources | rainfall [1] |
| Primary outflows | none [1] |
| Catchment area | 400 km² [1] |
| Max length | 8.6 km (5.3 mi) |
| Max width | 8.1 km (5.0 mi) |
| Surface area | 49 km² (19 mi²) [1] |
| Average depth | 45 m (150 ft) [1] |
| Max depth | 81 m (265 ft) [1] |
| Surface elevation | 150 m (490 ft) |
Lake Bosumtwi, situated about 30 km south-east of Kumasi and approximately 8 km across, is the only natural lake in Ghana[1]. This large crater lake is situated within an ancient impact crater. The lake is popular as a recreational area, as it is supposedly safe to swim in it.
Bosumtwi is a sacred lake to the Ashanti. According to traditional beliefs, the souls of the dead come here to bid farewell to their god Twi. Because of this, they only considered it permissible to fish in the lake from wooden planks (rather than the usual traditional canoes). There are about 30 villages in the lake area, with a combined population of about 70,000 people.
The Lake Bosumtwi impact crater is 10.5 km in diameter and is estimated to be 1.07 million years old, placing it in the Pleistocene period.[2] The crater was easy to find, however, there was a problem in distinguishing whether it was or was not caused by a meteor impact. This was because it is in the middle of a rainforest and filled with water to form the lake. The problem with this was that shatter cones and other rocks and minerals would be deep under vegetation and many of the features of an impact crater were eroded. However, scientists managed to confirm it was an impact crater after a dome in the centre, which is common in impact craters, was discovered buried beneath the lake's floor. The impact is believed to have been a very powerful one too because tektites presumably from the impact have been discovered as far away as the Côte d'Ivoire.
After the impact the landscape in the area went through several different stages caused by climate changes. Sometimes periods of heavy rainfall filled the whole crater with water so the lake level was up to the lowest points of the rim. These periods became obvious when fossils of fish were found on the top of the hills. The water was even flowing out of the basin through an overflow channel. But there were also times when the water level was so low that rain forest could come up inside the basin and the lake itself was only a small pond. This period lasted until about 300 years before present.
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, as if the little water wanted to save the animals life. The hunter never got the antelope but he settled close to the water and started catching the fish. And he called the place “Bosomtwe”, meaning “good antelope”. This story also gives a hint that by then the lake level was very low, and the dead tree giants standing offshore in the lake are evidence for it as they are over 300 years old.
The following centuries saw several wars about the lake as both the Ashanti and the Akim people claimed the area to be theirs. Finally, the Ashanti were victorious and secured Lake Bosumtwi for their kingdom. Each village in the lake area has its own shrine or fetish grove. With the arrival of christianity, some of the people lost their belief in those, but still many are worshipping them for help in bad times or against diseases. The spiritual centre of the lake is the Abrodwum Stone (see map). Here, all the lake people will sacrifice a cow when an omen of bad fish harvest occurs.This act is celebrated in the presence of his majesty, the Ashanti king, the Asantehene himself. In the ceremony, the guts of the cow will be given to the stone and the rest is thrown into the lake, so the crowd will rush into the water with cutlasses and axes to take their share of the meat. This happening is surely worth seeing it, but as the omen mentioned above depends on various different factors,it is hardly predictable.
In former times, it was a taboo to touch the water with iron things, so the people never used conventional boats. Traditionally they move on the lake using the padua, a wooden plank that needs a lot of skill to be handled in the right way.
Today the area belongs to Ashanti region.
The people are facing substantial problems caused by overfishing and inadequate farming methods. With the growing population the need for fish increases and with more people fishing the catches steadily decrease. That’s why the locals now focus more on farming. As more and more of the hills are converted into farmland, exposing the surface to the heavy rainfalls, erosion is degrading the soils.
Another problem is the lake level. It has always been an is still changing and many of the villages were submerged several times forcing the people to move up the slopes or outside the basin. That is why there are now double names like 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.
[edit] References
- ^ a b c d e f g Bosumtwi. LakeNet. Retrieved on 2007-02-18.
- ^ Bosumtwi. Earth Impact Database. Retrieved on 2007-02-18.
