Page:EB1911 - Volume 19.djvu/721

 Albertine Rift valley, in which lie the Albert Edward and Albert Nyanzas. For a considerable distance the water-parting between the Congo and the Nile is close to the Albert Nyanza and to the Nile as it flows from that lake, but not far north of Wadelai (2° 46′ N.) the hills recede and the Nile basin expands westward, over the wide area drained by the Bahr-el-Ghazal and its tributaries. In this region there is no well-marked watershed between the Congo and Nile systems, which interlace. Farther north the limit of the valley is marked by the hills of Darfur. Below that point the valley of the Nile extends but a mile or two into the desert.

The south-eastern limits of the Nile basin extend nearly to the western escarpment of the eastern Rift valley—the dividing plateau being a narrow one. North of the equator a bend is made westward to Mt. Elgon, which on the north-east sends its water towards Lake Rudolf. From Mt. Elgon the Nile watershed is some distance to the west of that lake, while to its north a turn is made again, the watershed including a great part of the Abyssinian highlands. Beyond 15° N. it follows a line generally parallel to the west shore of the Red Sea, except where diverted to the west by the basin of the Khor Baraka.

Source of the Nile.—The question of the sources of the Nile opens up a time-honoured controversy (see under Story of Discovery below). (q.v.) is the great reservoir whence issues the Nile on its long journey to the Mediterranean. But if the source of the river be considered to be the most remote headstream (measured by the windings of the stream), the distinction belongs to one of the upper branches of the Kagera. Among the feeders of Victoria Nyanza the Kagera is by far the most important, both for length of course and volume of water carried, draining the region of greatest rainfall round Lake Victoria. Three chief branches unite to form the Kagera, and of these the most important for the volume of water carried is said to be the Nyavarongo. The Nyavarongo is formed by the union of various mountain streams, the Rukarara and the Mhogo being the chief. The Rukarara rises in about 2° 20′ S., 29° 20′ E., at an elevation of some 7000 ft., in a picturesque and bracing region immediately east of the Albertine Rift valley. The Nyavarongo first flows north to about 1° 40 S., then turning in a sharp bend east and south, and on again reaching 2° 20′ S., unites with the Akanyaru just west of 30° E. The Akanyaru, which comes from the south-west, has been sometimes considered the larger stream, but according to Dr Richard Kandt it carries decidedly less water, while its course is shorter than that of the Nyavarongo. The combined stream takes an easterly and southerly direction, flowing in a swamp valley and joining a little west of 31° E. The third branch of the Kagera, the Ruvuvu, coming from the south. The source of the Ruvuvu is in about 2° 55′ S., 29° E., but its most southern tributary, and the most distant stream sending its waters towards the Nile, is the Lavironza. The Lavironza rises in about 3° 45′ S., 29° 50′ E., and flows north-east, joining the Ruvuvu, which has hitherto had an easterly direction, in about 30° 25′ E., 3° 10′ S. From this point the Ruvuvu flows east and north to its junction with the Nyavarongo. From this confluence the combined stream of the Kagera flows north and north-west in a level valley strewn with small lakes until almost 1° S., when it turns east, and finally empties itself into Victoria Nyanza just north of 1° S., the mouth forming a small projecting delta. Its lower course is navigable by shallow draught steamers. The total length of the Kagera, reckoning from the source of the Nyavarongo, is some 430 m. Its volume is stated to vary between 21,000 and 54,000 cub. ft. per second. All the other feeders of Victoria Nyanza are small and often intermittent rivers, the largest being probably the Nzoia, which enters on the north-east from the plateaus south of Mount Elgon. (The rivers which enter Albert Edward and Albert Nyanzas and, with those lakes, form the western sources of the Nile, are dealt with under and .)

The Victoria or Somerset Nile.—The ridge of high land which forms the northern shore of Victoria Nyanza is broken at its narrowest part, where the pent-up waters of the lake—through which a drift from the Kagera inlet to the Nile outlet is just perceptible—have forced a passage at the northern end of a beautiful bay named Napoleon Gulf. At this spot, 30 m. north of the equator, at an altitude of 3704 ft., the Nile issues from the lake between cliffs 200 and more ft. high with a breadth of some 500 yds. The scene is one of much grandeur. The escaping water precipitates itself over a rocky ledge with a clear fall of 16 ft. The falls, some 300 yds. across, and divided into three channels by two small wooded islands, are named the Ripon Falls, after Earl de Grey and Ripon (afterwards 1st marquess of Ripon), president of the Royal Geographical Society in 1859. The Victoria or Somerset Nile, as this section is called, has at first the character of a mountain stream, racing swiftly through a rocky channel often walled in by cliffs (at times 180 ft. high) and broken by picturesque islands and countless rapids. It receives the waters of several streams, which, rising within a few miles of the Victoria Nyanza, flow north. For 133 m. its course is N.N.W., when, on being joined by the river Kafu (on which Fort Mruli stands), about 1° 39′ N., 32° 20′ E., it takes the north-east direction of that channel, and it is not till 2° N. that the river again turns westward towards the Albert Nyanza. Seventy miles below the Ripon Falls the Nile enters a marshy lake of irregular outline, running mainly east and west, and known as Kioga (or Choga). The current of the Nile is clearly discernible along the western shore of this lake, which is 3514 ft. above the sea. Eastwards the lake breaks into several long arms, which receive the waters of other lakes lying on the plain west of Mount Elgon. One of these, named Lake Salisbury, lies in 1° 40′ N. and 34° E.; east of this lake and connected with it is Lake Gedge. Lake Kioga also receives the Mpologoma, a river which rises in the foothills of Elgon and flows east and north, attaining a width of 1 m.; and from the south (west of the Nile) a broad lacustrine river, the Seziwa. The Kioga lake system, lying north of the ridge which separates it from Victoria Nyanza, owes its formation in part to the waters pouring down from the Nyanza, and is in the nature of a huge Nile backwater. The lake itself is rarely more than 20 ft. deep; its greatest length is 85 m.; its greatest width 10 m. Below Mruli, the fall in the bed levels of the Nile, which up to this point has been comparatively gradual, increases considerably. At Karuma, where the western bend to the Albert Nyanza is made, the river falls over a wall-like ledge of rock, 5 ft. high, which extends across its bed. But the great feature of the Victoria Nile are the Murchison Falls (named by Sir Samuel Baker, their discoverer, after Sir Roderick Murchison, the geologist), situated in 2° 18′ N. and 31° 50′ E. At this point the river rages furiously through a rockbound pass, and, plunging through a cleft less than 18 ft. wide, leaps about 130 ft. into a spray-covered abyss. Downstream from these falls the river flows for some 14 m. between steep forest-covered hills, a wide and noble stream with a current so slow and steady that, at certain seasons, it is only from the scarcely perceptible drifting of the green water-plants called Pistia Stratiotes that it can be observed. About 24 m. below the Murchison Falls and 254 m. from the Victoria Nyanza the river enters, through a wide delta, and across a formidable bar, the N.E. end of Albert Nyanza. In its passages from the one lake to the other the Nile falls altogether about 1400 ft. Taking its name from a fort which once existed there, the delta district is known as Magungo.

From Albert Nyanza to the Plains.—Issuing from the north-west corner of Albert Nyanza some 5 m. from the spot where it entered that lake, the Nile, which is now known as the Bahr-el-Jebel, or Mountain river, flows in a generally northerly direction. As far as Dufile, 130 m. below Magungo, it has a gentle slope, a deep channel and a current generally slight. It forms a series of lake-like reaches often studded with reedy islands. Immediately below Dufile the Kuku mountains on the west and the Arju range on the east close in upon the river, which, from an average width of 700 yds., narrows to 230 yds. Here the hills cause the stream to make a sharp bend from the north-east to the north-west. Four or five miles lower down the river widens to 400 yds., and a large island divides the stream, the eastern channel carrying the main volume of water. This island marks the beginning of the Fola Rapids. At its southern end the water falls some 20 ft., and then, like a gigantic mill-race, rushes through a gorge 330 ft. long and nowhere more than 52 ft. wide, to leap into a deep cavity not more than 40 ft. across. Escaping from this “cauldron” the waters thunder on in a succession of rapids, which extend beyond the northern end of the island. In all the Fola Rapids are nearly 2 m. long. For the next 80 m. the Nile, save for the great volume of water, resembles a mountain torrent, its course interrupted by continual rapids. The last of these occurs at Bedden, where the river breaks through a line of low hills running athwart its channel. One of these hills forms an island in midstream. Below Bedden various stations are established upon the river. Fort Berkeley, in 4° 40′ N. (on the right bank), is the nearest to the rapids. Then follow Rejaf (left bank), Gondokoro (right bank) and Lado (left bank), all within 30 m. of one another. A striking feature of the scenery at Rejaf is a cone-shaped hill, about 370 ft. high, crowned by rocks which have the appearance of the ruins of an ancient castle. At Gondokoro the Nile is clear of the hill country, and enters a vast swamp-like expanse through which it flows with a very low slope and a very tortuous channel.

Between Albert Nyanza and the swamp region the Bahr-el-Jebel is joined by many streams. The most important of these affluents is the Asua (nearly 200 m. long), which enters the main stream from the east in 3° 50′ N. (19 m. N. of Dufile), but has little water in the dry season. The Asua and its subsidiary streams rise on the western versant of the Karamojo plateau and among the mountain ranges which run off from that plateau to the north-west, the most remote head-stream running originally due south.

The Region of Swamps.—The wide valley which the Nile enters at Gondokoro slopes so gradually towards the north that the river falls only some 182 ft. in a stretch of 475 m. Through this valley the river winds in an extremely tortuous course. Its channel has no banks, and the overflow has caused extensive swamps which are covered by a mass of papyrus and tall reeds, and are traversed by numerous shallow lagoons or “mayyas.” The shape of these lagoons is constantly altering, as also is that of the channels connecting them with the river. About 8 m. below Bor, many of the eastern “spills” unite and form a stream of considerable breadth, with a strong