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Zambezi

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                                 Zambezi
   The Zambezi and its river basin

                       The Zambezi and its river basin

   Origin           Near Mwinilunga, Zambia
   Mouth            Indian Ocean
   Basin countries  Zambia, Congo, Angola, Namibia, Botswana, Zimbabwe,
                    Mozambique
   Length           2,574 km (1,599 mi)
   Source elevation 1,500 m (4,922 ft)
   Avg. discharge   7,000 m³/s (247,240 ft³/s)
   Basin area       1,570,000 km² (606,177 mi²)

   The Zambezi (also spelled Zambesi) is the fourth-longest river in
   Africa, and the largest flowing into the Indian Ocean. The area of its
   basin is 1,570,000  km² (606,000  miles²), slightly less than half that
   of the Nile. The 2,574 km (1,600 mile) long river has its source in
   Zambia and flows through Angola, along the border of Namibia, Botswana,
   Zambia and Zimbabwe, to Mozambique, where it empties into the Indian
   Ocean.

   The Zambezi's most spectacular feature is Victoria Falls, the world's
   largest waterfalls. Other notable falls include the Chavuma Falls at
   the border between Zambia and Angola, and Ngonye Falls, near Sioma in
   Western Zambia. Over its entire course, the Zambezi is spanned by only
   five bridges: at Chinyingi, Katima Mulilo, Victoria Falls, Chirundu and
   Tete.

   There are two main sources of hydroelectric power on the river. These
   are the Kariba Dam, which provides power to Zambia and Zimbabwe and the
   Cabora-Bassa Dam in Mozambique which provides power to South Africa.
   There is also a smaller power station at Victoria Falls.

Course

The upper river

   After flowing to the south-west for about 240 km (150 miles), the river
   turns south, and is joined by many tributaries. A few miles above
   Kakengi, the river widens from 100 to 350 metres (330 to 1,150 ft), and
   below Kakengi are a number of rapids ending in the Chavuma Falls, where
   the river flows through a rocky fissure. The first of its large
   tributaries to enter the Zambezi is the Kabompo River in the
   north-western province of Zambia. A little further south is the
   confluence with the much larger Lungwebungu River. The savanna through
   which the river has flowed gives way to a more open bush valley,
   studded with Borassus palm trees. Dense vegetation is confined to
   narrow strips of matted forest which skirt the first few hundred metres
   of the sources of the Zambezi and its tributaries during the first
   160 km (100 miles) or so.
   Zambezi River in North Western Zambia
   Enlarge
   Zambezi River in North Western Zambia

   From 1500 metres (4,900 ft) at the source, the river drops to about
   1100 metres (3,600 ft) at Kakengi, 350 km (220 miles) downstream. From
   this point until the Victoria Falls, the level of the basin is very
   uniform, dropping only by another 180 metres (590 ft). Thirty
   kilometers (19 miles) below the confluence of the Lungwebungu the
   country becomes flat, and in the rainy season is largely covered by
   floods. Eighty kilometers (50 miles) further down, the Luanginga, which
   with its tributaries drains a large area to the west, joins the
   Zambezi. A few kilometres higher up on the east the main stream is
   joined by the Luena.

   A short distance downstream of the confluence with the Luanginga is
   Lealui, one of the capitals of the Lozi people who populate the semi-
   autonomous Zambian region of Barotseland. The chief of the Lozi has two
   compounds, the other being at Limulunga. Limulunga is on high ground
   and serves as the capital during the rainy season. The annual move from
   Lealui to Limulunga is a major event, celebrated as one of Zambia's
   best known festivals, the Kuomboka.

   After Lealui, the river turns to the south-east. From the east it
   continues to receive numerous small streams, but on the west is without
   tributaries for 240 km (150 miles), when the Cuando River joins it.
   Before this, the Ngonye Falls and subsequent rapids interrupt
   navigation. South of Ngonye Falls, the river briefly borders Namibia's
   Caprivi Strip. The strip projects from the main body of Namibia, and
   results from the colonial era: it was added to German South-West Africa
   expressly to give Germany access to the Zambezi.

   Below the junction of the Cuando and the Zambezi the river bends almost
   due east. Here, the river is very broad and shallow, and flows fairly
   slowly, but as it flows eastward towards the border of the great
   central plateau of Africa it reaches a chasm into which the Victoria
   Falls plunge.

The middle Zambezi

   Victoria Falls, the end of the upper Zambezi and beginning of the
   middle Zambezi
   Enlarge
   Victoria Falls, the end of the upper Zambezi and beginning of the
   middle Zambezi

   The Victoria Falls are considered the boundary between the upper and
   middle Zambezi. Below them the river continues to flow due east for
   about 200 km (120 miles), cutting through perpendicular walls of basalt
   20 to 60 metres (65 to 200 ft) apart in hills 200 to 250 metres (650 to
   820 ft) high. The river flows swiftly through the gorge, the current
   being continually interrupted by reefs. Beyond the gorge are a
   succession of rapids which end 240 km (150 miles) below Victoria Falls.
   Over this distance, the river drops 250 metres (820 ft).

   At this point, the river enters Lake Kariba, created in 1959 following
   the completion of the Kariba Dam. The lake is one of the largest
   man-made lakes in the world, and the hydroelectric power-generating
   facilities at the dam provide electricity to much of Zambia and
   Zimbabwe.

   The Luangwa and the Kafue are the two largest left-hand tributaries of
   the Zambezi. The Kafue joins the main river in a quiet deep stream
   about 180 metres (590 ft) wide. From this point the northward bend of
   the Zambezi is checked and the stream continues due east. At the
   confluence of the Luangwa (15°37′ S) it enters Mozambique.

   The middle Zambezi ends when the river enters Lake Cahora Bassa (also
   spelled Cabora Bassa). Formerly the site of dangerous rapids known as
   Kebrabassa, the lake was created in 1974 by the construction of the
   Cahora Bassa Dam.

The lower river

   The lower Zambezi's 650 km (400 miles) from Cahora Bassa to the Indian
   Ocean is navigable, although the river is shallow in many places during
   the dry season. This shallowness arises as the river enters a broad
   valley and spreads out over a large area. Only at one point, the Lupata
   Gorge, 320 km (200 miles) from its mouth, is the river confined between
   high hills. Here it is scarcely 200 metres wide. Elsewhere it is from 5
   to 8 km (3 to 5 miles) wide, flowing gently in many streams. The river
   bed is sandy, and the banks are low and reed-fringed. At places,
   however, and especially in the rainy season, the streams unite into one
   broad fast-flowing river.
   The Zambezi's delta
   Enlarge
   The Zambezi's delta

   About 160 km (100 miles) from the sea the Zambezi receives the drainage
   of Lake Malawi through the Shire River. On approaching the Indian
   Ocean, the river splits up into a number of branches and forms a wide
   delta. Each of the four principal mouths, Milambe, Kongone, Luabo and
   Timbwe, is obstructed by a sand bar. A more northerly branch, called
   the Chinde mouth, has a minimum depth at low water of 2 metres at the
   entrance and 4 metres further in, and is the branch used for
   navigation. 100 km (60 miles) further north is a river called the
   Quelimane, after the town at its mouth. This stream, which is silting
   up, receives the overflow of the Zambezi in the rainy season. The delta
   of the Zambezi is today about half as broad as it was before the
   construction of the Kariba and Cahora Bassa dams controlled the
   seasonal variations in the flow rate of the river.

   The region drained by the Zambezi is a vast broken-edged plateau
   900–1200 metres high, composed in the remote interior of metamorphic
   beds and fringed with the igneous rocks of the Victoria Falls. At
   Shupanga, on the lower Zambezi, thin strata of grey and yellow
   sandstones, with an occasional band of limestone, crop out on the bed
   of the river in the dry season, and these persist beyond Tete, where
   they are associated with extensive seams of coal. Coal is also found in
   the district just below the Victoria Falls. Gold-bearing rocks occur in
   several places.

Tributaries

   The Zambezi has numerous tributaries. Some of the more important ones
   are described here, in order from source to sea.

   The Kabompo rises in the high land which forms the eastern watershed
   between the Zambezi and Congo systems. It is formed itself by the
   confluence of the upper Kabompo and the somewhat larger Lunga River,
   and flows into the Zambezi north of the town of Lukulu. The
   Lungwebungu, which enters the Zambezi from the west just south of the
   confluence with the Kabompo River, is 200 metres wide in its upper
   course, flowing in a valley bordered by white sand covered in thin
   forest, its floor forming at times an inundated plain 2 to 3 miles
   wide.

   The Cuando River, largest of the river's western tributaries, has the
   ruined capital of the Makololo people on its lower reaches. It rises in
   Angola, and forms the border between Zambia and Angola for part of its
   course, before curving to the south, then flowing east into the
   Zambezi. In this eastward stretch the Cuando flows through a vast reedy
   swamp studded with alluvial islands for 110 km (70 miles), and at its
   most southern bend is joined by the Magwekwana, which in time of flood
   receives some of the surplus water of the Okavango. This surplus water,
   received after most of the flood water of the Cuando has passed, raises
   the level of the lake and holds up the waters of the Cuando for some
   miles above it.

   The largest tributary of the middle Zambezi, the Kafue, rises in
   Zambia's Copperbelt Province near the border with Democratic Republic
   of Congo at an elevation of 1350 metres in thick forest country. The
   main headstream is later joined by the Lunga River or Luanga. The
   Itezhi-Tezhi Dam is an important source of hydroelectric power from the
   Kafue River, and the river also supports a great deal of wildlife,
   which is protected by Zambia's largest national park, Kafue National
   Park. The lower Kafue has a series of waterfalls and cataracts,
   dropping several hundred feet in 25 km (15 miles).

   The next large tributary to the east is the Luangwa, which rises near
   the north-west corner of Lake Malawi and in its upper course runs
   parallel to its western shores. The Luangwa flows in a generally level
   valley, bounded by steep plateau escarpments, and is generally shallow
   and rapid, though fairly wide. Its tributaries the Lunsemfwa River and
   Lukasashi River drain a large area of the western plateau of Zambia.
   The Luangwa joins the Zambezi a little above the town of Zumbo. The
   Luangwa Valley is an important wildlife conservation area, and contains
   North Luangwa National Park and South Luangwa National Park. The
   Luangwa defines the border between Zambia and Mozambique for about
   75 km before it joins the Zambezi.

   From the south the middle Zambezi receives various rivers which water
   northern Zimbabwe—the Shangani, Sanyati, and Hanyani, besides minor
   streams. The Mazoe, which rises in Mashonaland, joins the Zambezi below
   the Cahora Bassa Dam.

Exploration of the river

   Satellite image showing Victoria Falls and subsequent series of
   zigzagging gorges
   Enlarge
   Satellite image showing Victoria Falls and subsequent series of
   zigzagging gorges

   The Zambezi region was known to medieval geographers as the Empire of
   Monomotapa, and the course of the river, as well as the position of
   Lakes Ngami and Nyasa, were given broadly accurately in early maps.
   These were probably constructed from Arab information.

   The first European to visit the upper Zambezi was David Livingstone in
   his exploration from Bechuanaland between 1851 and 1853. Two or three
   years later he descended the Zambezi to its mouth and in the course of
   this journey discovered the Victoria Falls. During 1858–60, accompanied
   by John Kirk, Livingstone ascended the river by the Kongone mouth as
   far as the Falls, and also traced the course of its tributary the Shire
   and reached Lake Malawi.

   For the next 35 years very little exploration of the river took place,
   but in 1889 the Chinde channel north of the main mouths of the river
   was discovered. Two expeditions led by Major A. St Hill Gibbons in 1895
   to 1896 and 1898 to 1900 continued the work of exploration begun by
   Livingstone in the upper basin and central course of the river.
   Portuguese explorer Serpa Pinto examined some of the western
   tributaries of the river and made measurements of the Victoria Falls in
   1878.

Wildlife

   The river supports large populations of many animals. Hippopotamuses
   are abundant along most of the calm stretches of the river, and many
   crocodiles are also present. Monitor lizards are found in many places.
   Bird life is abundant, with species including heron, pelican, egret and
   African Fish Eagle present in large numbers. Riverine woodland also
   supports many large animals, such as buffalo, zebras, giraffes and
   elephants. However, below Kariba and Cahora Bassa dams, the cessation
   of annual flooding has seen the area of this habitat greatly reduced
   and a corresponding reduction in the populations of the large mammals.

   The Zambezi also supports several hundred species of fish, some of
   which are endemic to the river. Important species include cichlids
   which are fished heavily for food, as well as catfish, tigerfish,
   yellowfish and other large species. The bull shark is sometimes known
   as the Zambezi Shark after the river but is found around the world. It
   normally inhabits coastal waters but has been found far inland in many
   large rivers including the Zambezi. It is an aggressive shark which has
   been responsible for several attacks on humans.

Economy

   The river and its floodplain near Mongu in Zambia
   Enlarge
   The river and its floodplain near Mongu in Zambia

   The population of the Zambezi river valley is estimated to be about 32
   million. About 80% of the population of the valley is dependent on
   agriculture, and the upper river's flood plains provide good
   agricultural land.

   Communities by the river fish extensively from it, and many people
   travel from far afield to fish. Some Zambian towns on roads leading to
   the river levy unofficial 'fish taxes' on people taking Zambezi fish to
   other parts of the country. As well as fishing for food, game fishing
   is a significant activity on some parts of the river. Between Mongu and
   Livingstone, several safari lodges cater for tourists who want to fish
   for exotic species, and many also catch fish to sell to aquaria.

   The river valley is rich in mineral deposits and fossil fuels, and coal
   mining is important in places. The dams along its length also provide
   employment for many people near them, in maintaining the hydroelectric
   power stations and the dams themselves. Several parts of the river are
   also very popular tourist destinations. Victoria Falls receives over
   1.5 million visitors annually, while Mana Pools and Lake Kariba also
   draw substantial tourist numbers.

Transportation

   Victoria Falls Bridge. 1975 photo.
   Enlarge
   Victoria Falls Bridge. 1975 photo.

   The river is frequently interrupted by rapids and so has never been an
   important long-distance transport route. However, along short
   stretches, it is often more convenient to travel by canoe along the
   river rather than on the unimproved roads which are often in very poor
   condition due to being regularly submerged in flood waters, and many
   small villages along the banks of the river are only accessible by
   boat.

   There are only five bridges across the river along its entire course,
   of which one is a footbridge only. However, at many locations pontoons
   ferry people and vehicles across the river. Victoria Falls Bridge was
   the first to be built, and was completed in April 1905. It was
   initially intended as a link in Cecil Rhodes' scheme to build a railway
   from Cape Town to Cairo. The bridge is 250 m (820 ft) across, with a
   main arch spanning 150 m (490 ft), and the top of the bridge is 125 m
   (410 ft) above the low-water level of the river.

   Later bridges were constructed at Chirundu in Zambia (1939, replaced in
   2003), Tete in Mozambique (1960s) and Chinyingi in northern Zambia in
   the 1970s (footbridge only). 2004 saw the completion of a bridge
   crossing the river from Sesheke in Zambia with Katima Mulilo in
   Namibia, completing the TransCaprivi Highway and connecting Lusaka in
   Zambia with Walvis Bay on the Namibian coast.

Ecology

   Lake Cahora Bassa in Mozambique, one of the river's major sources of
   hydroelectric energy
   Enlarge
   Lake Cahora Bassa in Mozambique, one of the river's major sources of
   hydroelectric energy

   Sewage effluent is a major cause of water pollution around urban areas,
   as inadequate water treatment facilities in all the major cities of the
   region force them to release untreated sewage into the river. This has
   resulted in eutrophication of the river water and has facilitated the
   spread of diseases of poor hygiene such as cholera, typhus and
   dysentery.

   The construction of two major dams regulating the flow of the river has
   had a major effect on wildlife and human populations in the lower
   Zambezi region. When the Cahora Bassa Dam was constructed in 1973, its
   managers allowed it to fill in a single flood season, going against
   recommendations to fill over at least two years. The drastic reduction
   in the flow of the river led to a 40% reduction in the coverage of
   mangroves, greatly increased erosion of the coastal region and a 60%
   reduction in the catch of prawns off the mouth due to the reduction in
   emplacement of silt and associate nutrients. Wetland ecosystems
   downstream of the dam shrank considerably.

Major towns

   Along much of the river's length, the population is sparse, but
   important towns and cities along its course include the following:
     * Katima Mulilo (Namibia)
     * Mongu, Lukulu, Livingstone, & Sesheke (Zambia)
     * Victoria Falls & Kariba (Zimbabwe)
     * Songo & Tete (Mozambique)

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