Largest Lakes in Ethiopia

Geology

Lake Turkana is an East African Rift feature. A rift is a weak place in the Earth's crust due to the separation of two tectonic plates, often accompanied by a graben, or trough, in which lake water can collect. The rift began when East Africa, impelled by currents in the mantle, began separating from the rest of Africa, moving to the northeast. Currently, the graben is 320 km wide in the north of the lake, 170 km in the south. This rift is one of two, and is called the Great or Eastern Rift. There is another to the west, the Western Rift.

Lake Turkana is a unique feature of the East African landscape. Besides being a permanent desert lake, it is the only lake that retains water originating from two separate catchment areas of the Nile.

Overview

Lake Tana was formed by volcanic activity, which blocked the flow of inflowing rivers in the early Pleistocene, about 5 million years ago.

The lake was originally much larger than it is today. Seven large permanent rivers feed the lake as well as 40 small seasonal rivers. The main tributaries to the lake are Gilgel Abbay (Little Nile River), and the Megech, Gumara, and Rib rivers.

Lake Tana has a number of islands, whose number varies with the lake's level. It has fallen about 6 feet (1.8 m) in the last 400 years. According to Manuel de Almeida, a Portuguese missionary in the early 17th century, there were 21 islands, seven or eight of which had monasteries on them "formerly large, but now much diminished."

Geography

When the Lake Chew Bahir is filled, it stretches into northern Kenya. Lying at the center of the Stephanie Wildlife Sanctuary, the lake measures some 40 by 15 miles (64 by 24 km).

This lake is the southernmost and lowest (1,880 ft; 570 m) of a series of lakes which lie in the north-easterly continuation of the Great Rift Valley; its watershed is separated from the watershed of Lake Turkana by the Humu Range and the hills south of it. The Kumbi Range rises on its eastern side. Chew Bahir is fed from the north by the Weito River, and its tributary the Galana Sagan. The Galana Sagan receives the overflow of Lake Chamo in some years, but no permanent connection exists.

History

Count Sámuel Teleki was the first European to visit the lake in 1888, and named it for Princess Stéphanie of Belgium, the wife of Crown Prince Rudolf of Austria. Following Teleki's visit, Lake Chew Bahir and the neighboring lakes were explored by Arthur Donaldson Smith, Vittorio Bottego, M. S. Welby, Oscar Neumann and others. J. J. Harrison in 1899 found the lake quite dried up, and two years later Count Wickenburg found water only in the northern part. In 1960 the lake covered about 2,000 km2, but shrank to a swamp over the rest of the 20th century.

Overview

Lake Abbe is the ultimate destination of the waters of the Awash River. It lies at the Afar triple junction, the central meeting place for the three pieces of the Earth's crust, a defining feature of the Afar Depression. Here three pieces of Earth's crust are each pulling away from that central point, though not all at the same speed.

On the northwest shore rises Mount Dama Ali (1068 m or 3,504 ft), a dormant volcano, while along the southwestern and southern shores extend vast salt flats, 10 km in width. Besides the Awash, seasonal affluents of Lake Abbe include two wadis, the Oleldere and Abuna Merekes, which enter the lake from the west and south, crossing the salt flats.

Climate

The Lake Abbe's climate offers year-round sunny skies and dry air. It has less than 172 millimetres (7 in) mean annual rainfall and a summer average temperature between 30 and 40 °C (86 and 104 °F). Temperatures in the coldest months range between 21 and 30 °C (70 and 86 °F) on average.

Overview

Lake Chamo's northern end lies in the Nechisar National Park. According to figures published by the Central Statistical Agency, it is 32 kilometers long and 13 wide, with a surface area of 317 square kilometers and a maximum depth of 14 meters with a catchment of about 18757 square kilometers in size. Other sources locate it on an elevation of 1,235 meters with a length of 26 km a widths of 22 km an area of 551 square kilometers a catchment of 2220 square kilometers and a maximum depth of 10 meters.

The lake is fringed with beds of Typha, as well as wetlands. It is fed by the Kulfo River and several small streams, as well as overflow from Lake Abaya brought to it by the Ualo River.

Geography

Located in the Misraq Shewa Zone of the Oromia Region, close to the capital and largest city of Ethiopia, Addis Ababa, the Koka Reservoir is popular with tourists and city-dwellers. There is a variety of wildlife and birds around the lake. The reservoir supports a fishing industry; according to the Ethiopian Department of Fisheries and Aquaculture, 625 tonnes (615 long tons; 689 short tons) of fish are landed each year, which the department estimates is either 52% or 89% of its sustainable amount. Both the reservoir and the dam are threatened by increasing sedimentation caused by environmental degradation as well as the invasive water hyacinth.