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Posts tagged Kalahari Desert

Orange River Flowing Across South Africa Near Upington

28.4S 21.2E

December 4th, 2009 Category: Rivers

South Africa - November 17th, 2009

South Africa - November 17th, 2009

This image focuses on a stretch of the Orange River in South Africa, near the town of Upington (located approximately in the middle of the visible river segment). This Southern Kalahari Desert town is situated within the fertile Orange River Valley, a bright green ribbon that brings life-giving water from the Lesotho Highlands and snakes across the semi-arid Northern Cape landscape.

The Orange River that flows through Upington is the result of the confluence of the Orange and Vaal rivers at the town of Douglas, approximately 300 km upstream. The geography in this area varies from sandy red dunes, rock faced ‘koppies’ hills, African veld and extremely fertile agricultural areas.

The Namib and Kalahari Deserts – April 18th, 2009

April 18th, 2009 Category: Image of the day

Namibia - April 5th, 2009

Namibia - April 5th, 2009

The arid land of two deserts gives an orange tone to this image, which covers parts of Namibia (left), Botswana (right) and South Africa (below).

The Namib Desert is visible on the far left. Its borders are made fairly evident by the outline of its orange-red sands.

East of the Namib, the Kalahari Desert covers much of the rest of the image. It is a large, arid desert area in southwestern Sub-Saharan Africa extending 900,000 km² (225,000 sq. mi.), covering much of Botswana and parts of Namibia and South Africa. It has huge tracts of excellent grazing after good rains.

The Kalahari has vast areas covered by red sand without any permanent surface water. Drainage is by dry valleys, seasonally inundated pans, and the large salt pans of the Makgadikgadi Pan in Botswana and Etosha Pan in Namibia.

However, the Kalahari is not a true desert. Parts of the Kalahari receive over 250 mm (9.8″) of erratic rainfall annually and are quite well vegetated; it is only truly arid in the southwest with under 175 mm (6.9″) of rain annually, making the Kalahari a fossil desert. Summer temperatures in the Kalahari range from 20 to 45°C (68–113°F).

Okavango River and Delta, Botswana

March 31st, 2009 Category: Rivers

Botswana - March 23rd, 2009

Botswana - March 23rd, 2009

Parts of southern Angola (top left), southern Zambia (top right), Namibia (bottom left) and Botswana (bottom right) can be seen here.

The Okavango River runs across the image just above the middle, before emptying onto the sands of the Kalahari Desert in Botswana and creating the Okavango Delta (or Okavango Swamp).

This is the world’s largest inland delta, and an uncommon end for the Okavango River, considered unusual because it does not have an outlet to the sea.

Although the area around the delta appears quite well irrigated and green with vegetation, the true flood period will not begin for another month.

Okavango Delta, Botswana

January 16th, 2009 Category: Lakes

Okavango Delta in Botswana - November 29th, 2008

Okavango Delta in Botswana - November 29th, 2008

The Okavango Delta is created by the Okavango River, which is unusual in that it has no outlet to the sea.

Instead, it empties onto the sands of the Kalahari Desert in Botswana, irrigating 15,000 km², and thus creating the Okavango Delta (or Okavango Swamp). This is the world’s largest inland delta.

Each year some 11 cubic kilometres of water reach the delta and the nearby Moremi Wildlife Reserve. Some of this water reaches further south to create Lake Ngami.

The waters of the Okavango Delta are subject to seasonal flooding, which begins about mid-summer in the north and six months later in the south (May/June).

The water from the delta is evaporated relatively rapidly by the high temperatures, resulting in a cycle of cresting and dropping water in the south. Islands can disappear completely during the peak flood, then reappear at the end of the season.

The water entering the delta is unusually pure, due to the lack of agriculture and industry along the Okavango River.

It passes through the sand aquifers of the numerous delta islands and evaporates/transpirates by leaving enormous quantities of salt behind. These precipitation processes are so strong that the vegetation disappears in the center of the islands and thick salt crusts are formed.

In the image, we can see the delta during a period in which it appears green with vegetation and not much salt is visible. As there is little agriculture and industry along the river north of the delta, the water is not colored tan by runoff.

source Wikipedia