ZAMBEZI, the fourth in size of the rivers of Africa, and the largest of those flowing eastwards to the Indian ocean. Its length (taking all curves into consideration) is about 2,200 m. The area of its basin, according to Dr. Bludau, is 513,500 sq.m., or rather less than half that of the Nile. The main channel is clearly marked from beginning to end. The river takes its rise in 11° 21' 3" S., 22' E. The source lies in British territory in a depression of an undulating country 5,000 ft. above the sea, covered with bracken and open forest. The water, like that of all the rivers of the neighbourhood, issues from a black marshy bog. Eastward of the source the water-parting between the Congo and Zambezi basins is a well-marked belt of high ground, failing abruptly north and south, and running nearly east and west between I I° and 12° S.
The Upper River.—The infant Zambezi, after pursuing a south-westerly course for about 15o m., turns more directly south and, receives on either side numerous small tributaries. A few miles above Kakengi (in 12° 24' S.), the Zambezi, narrow, pic turesque and tortuous, suddenly widens from ioo to 35o yd.
Below Kakengi are a number of rapids ending (13° 7' S.) in the Suapuma cataracts. At this point the river flows tumultuously through a rocky fissure.
The first of its large tributaries to enter the Zambezi is the Kabompo, a left-hand affluent. It joins the main stream in 26' S. A little lower down (in 14° 18' S.) the Zambezi receives from the west the waters of a much larger stream than the Kabompo, namely, the Lungwebungu. The land, from 5,000 ft. at the source, falls gradually to 3,60o ft. at Kakengi—a distance of 220 m. From this point until the Victoria Falls are reached 500 m.—the level of the Zambezi basin is very uniform, the fall being in this distance 600 ft. only. Twenty miles below the confluence of the Lungwebungu the country becomes flat, and in the rainy seasons is largely covered by floods. From the east the Zambezi continues to receive numerous small streams, but on the west is without tributaries for 15o m., when the great
river formerly misnamed the Chobe, but known to the natives as Kwando or Linyante, joins it (in 17° 47' S.).
The Middle Zambezi.—The Victoria Falls are reached some 6o m. below the Kwando confluence. The surrounding country is formed of horizontal flows of basic lavas, which are traversed by two well marked sets of joints. Along these the river, fol lowing an extremely angular course, has eroded a great canon, about 400 f t. deep and in many places, with vertical sides. (See Victoria Falls.) Into the canon the river plunges over a vertical wall of rock. The narrow gorge can be traced more or less con tinuously along its course for about 4o miles. The middle course of the river may be said to extend for Boo m. below the Victoria Falls to the Kebrabasa Rapids, where the Zambezi crosses the great East African escarpment, and enters the coastal belt.
The Lower River.—The lower Zambezi-400 m. from Kebra basa Rapids to the sea—presents no obstacles to navigation save the shallowness of the stream in many places in the dry season. This shallowness arises from the different character of the river basin. Instead of, as in the case of the middle Zambezi, flowing mainly through hilly country with well-defined banks, the river traverses a broad valley and spreads out over a large area. Only at one point, the Lupata Gorge, 200 m. from its mouth, is the river confined between high hills. Here it is scarcely 200 yd. wide. Elsewhere it is from 3 to 5 m. wide, flowing gently in many streams. The river-bed is sandy, the banks are low and reed-fringed. At places, however, and especially in the rainy season, the streams unite into one broad swift-flowing river. About i oo m. from the sea the Zambezi receives the drainage of Lake Nyasa through the river Shire. On approaching the ocean, which it reaches in 18° 50' S. the Zambezi 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.