|
|
![]() Helping San Diego, California and beyond since 1997.
|
|
Click here and add this page to your favorites!

|
Encyclopedia Britannica - Main :: CAU-CHA |
|
|
CHAD , a lake of northern Central Africa lying between 12 5o' and 14 lo' N. and 13 and 150 E. The lake is situated about 85o ft. above the sea in the borderland between the fertile and wooded regions of the Sudan on the south and the arid steppes which merge into the Sahara on the north. The area of the lake is shrinking owing to the progressive desiccation of the country, Saharan climate and conditions replacing those of the Sudan. The drying-up process has been comparatively rapid since the middle of the 19th century, a town which in 185o was on the southern margin of the lake being in 1905 over 20 M. from it. On the west the shore is perfectly flat, so that a slight rise in the water causes the inundation of a considerable areaa fact not without its influence on the estimates made at varying periods as to the size of the lake. Around the north-west and north shores is a continuous chain of gently sloping sand-hills covered with bush
are plentiful. In the east
east
the central sections. The open water varies in depth from 3 ft. in the north-west to over 20 in the south, where desiccation is less apparent. Fed by the Shari (q.v.) and other rivers, the lake has no outlet and its area varies according to the season. The flood water brought down by the Shari in December and January causes the lake to rise to a maximum of 24 ft., the water spreading over low-lying ground, left dry again in May or June. But after several seasons of heavy rainfall the waters have remained for years beyond their low-water level. Nevertheless the secular shrinking goes on, the loss by evaporation and percolation exceeding the amount of water received; whilst, on the average, the rainfall is diminishing. In 187o the lake rose to an exceptional height, but since then, save in 1897, there has been only the normal seasonal rise. The prevalent north-east wind causes at times a heavy swell on the lake. Fish abound in its waters, which are sweet, save at low-level, when they become brackish. The lagoons are believed to act as purifying pans in which the greater part of the salt in the water is precipitated. In the south-west end of the lake the water is yellow, caused by banks of clay; elsewhere it is clear. The southern basin of Chad is described under the Shari, which empties its waters into the lake about the middle of the southern shore, forming a delta of considerable extent. Beyond the south-east corner of the lake is a depression known as the Bahr-el-Ghazal (not to be confounded with the Nile affluent of CHADERTON
the same name). This depression is the termination of what is in all probability the bed of one of the dried-up Saharan rivers. Coming from the Tibesti highlands the Bahr-el-Ghazal has a south-westerly trend to Lake Chad. Near the lake the valley was formerly swampy, and at high-water the lake overflowed into it. There was also at one time communication between the Shari and the Bahr-el-Ghazal, so that the water of the first-named stream reached Chad by way of the Bahr-el-Ghazal. There is now neither inlet nor outlet to the lake in this direction, the mouth of the Ghazal having become a fertile millet field. There is still, however, a distinct current from the Shari delta to the east end of the lakeknown to the natives, like the depression beyond, as the Bahr-el-Ghazalindicative of the former overflow outlet. Besides the Shari, the only important stream entering Lake Chad is the Waube or Yo (otherwise the Komadugu Yobe), which rises near Kano, and flowing eastward enters the lake on its western side 40 M. north of Kuka. In the rains the Waube carries down a considerable body
Lake Chad is supposed to have been known by report to Ptolemy
Tripoli
Dixon
Denham . By them the lake was named Waterloo. In 185o James Richardson, accompanied by Heinrich Barth and Adolf Overweg, reached the lake, also via Tripoli
Lenfant
See the works of Denham , Clapperton, Barth and Nachtigal cited in the biographical notices; Geog. Journal, vol. xxiv. (1904); Capt. Tilho in La Geographie (March 1906) ; Boyd Alexander, From the Niger to the Nile, vol. i. (London, 19o7); A. Chevalier, Mission Chari-Lac Tchad 1902-1904 (Paris., 1908) ; E. Lenfant
End of Article: CHAD If you wish, you can link directly to this article.
<a href="http://jcsm.org/StudyCenter/Encyclopedia/CAU_CHA/CHAD.html"> CHAD </a> |
|
|
(Previous) CHACONNE (Span. chacona) |
(Next) CHAD [CEADDA], SAINT (d. 672) |
|
Sponsored Advertisements