The Zambezi Central Africa's River of Life
Part 1 in a Series by Cecil Keen

The Zambezi is one of the great rivers of Africa and its long course has some very interesting features. Click on the map below to see an enlargement. Notice that if you follow the direction of the river from its headwaters near the point where the boundaries of Angola, the Democratic Republic of Congo (formerly Zaire), and Zambia come together, the Zambezi seems to be heading inland towards the Okavango Swamp in Botswana. However, just at the border of Zambia and Zimbabwe, this river changes direction and heads northeast and then east to its mouth on the coast of Mozambique. What accounts for this?

The answer, according to the theory of plate tectonics, can be found millions of years ago when Africa was the middle of the supercontinent, Pangea. In that time, there were huge inland seas, one of which was in present day Botswana and into which the Zambezi flowed. When the supercontinent broke up, these inland seas drained and the course of the lower reaches of the Zambezi river was created.

(Click map to see enlargement)

The Zambezi River flows westwards and southwards from its headwaters to be joined by the Kabompo River (originating in northern Zambia) and the Lungue-Bungo River (originating in central Angola). Near the confluence of these three rivers, which flow over a vast inland plateau, there is an extensive remnant inland swamp. Out of this soggy region in northern Borotseland, the river forms again and flows south and southeastwards for 200 miles (320 km) and then turns abruptly east to flow for the rest of its path towards the Indian Ocean, 1000 miles (1600 km) away. Shortly into its eastward path (about 100 miles, 160 km) the river drops off the inland plateau. The plateau edge is underpinned by layers of sandstone and massive basaltic lava flows in which there is an intersecting network of vertical fractures that cross each other at sharp angles. These fractures form lines of weakness and the Zambezi's power has cut deeply into them carving a zig-zag pathway of gorges, and giving us one of the natural wonders of the world, the Victoria Falls, as it plunges 350 ft (107 meters) over the plat eau edge.(see Part 2 of this series).

Gorges also occur at several places along the rest of the river's pathway. At two of these, humans have taken advantage of the narrow chasm to build hydro-electric dams. These give rise to two inland lakes, Lake Kariba and the Cabora Bassa Reservoir (see Part 3). The Zambezi's two major tributaries enter it from the north. The Kafue River joins the Zambezi about 50 miles downstream from Lake Kariba, and flows in across the Zambian central plains, again having its origins in a boggy beginning, the Lukunga Swamp. The Kafue is the river of life for most of Zambia and much of that country's food supply comes directly and indirectly from this water. The second river, the Shire (or Chire) joins the Zambezi just 100 miles (160 km) from the coast. It originates from Lake Malawi which is one of the large elongated lakes of Africa forming part of the Great Rift Valley region of the continent. The Shire River is an outflow from this lake and feeds the Zambezi with an abundant supply of water, especially in the wet season.

The Zambezi River is one of Africa's rivers of life. Throughout the 1653 miles (2660 km) of its course, it gives water to humans who drink it and use it for crop growing, who capture its energy for hydro-electric power, who fish for food, and who enjoy its environments for recreation. It also supports an abundant wealth of aquatic and animal life -- some are unique to Africa (see part 4). Join me in the following weeks to learn more about one of the greatest rivers in the continent of Africa.

Part 2: One of the Natural Wonders of the World - the Victoria Falls

Part 3: The Zambezi Reservoirs of Water: Dams on the River

To learn more about the Zambezi River, click here!

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