1911 Encyclopædia Britannica/Rukwa

RUKWA (sometimes also Rikwa and Hikwa), a shallow lake in German East Africa, lying 2650 ft. above the sea in a N.W. continuation of the rift-valley which contains Lake Nyasa. The sides of the valley here run in steep parallel walls 30 to 40 m. apart, from S.E. to N.W., leaving between them a level plain extending from about 7½° to 8½° S. This whole area was probably once covered by the lake, but this has shrunk so that the permanent water occupies only a space of 30 m. by 12 at the S. immediately under the E. escarpment. In the rains its extends some 40 m. farther N., and the north of the plain is likewise then covered with water to a depth of about 4 ft. The rest of the plain is a bare expanse intensely heated by the sun in the dry season, and forming a tract of foul mud near the lake shores. But in 1903–4 the level of the lake rose so that the waters covered the whole depression. The lake has two large feeders, one coming from the W., the other from the S.E. The W. feeder, the Saisi, or Momba, rises in 80° 50′ S., 31° 30′ E., and traverses a winding valley cut out of the high plateau between lakes Nyasa and Tanganyika. It enters the lake on its N.W. side. The other chief feeder, the Songwe, rises in 9° 8′ S., 33° 30′ E. on the same plateau as the Saisi and flows N.W., entering Rukwa at its S. end. The Songwe is joined about 50 m. about its mouth by the Rupa, whose head-waters are in the high-lying land N.E. of Rukwa. The maximum depth of the lake is about 10½ ft. Its water is very brackish and of a milky colour from the mud stirred up by the wind. It contains great quantities of fish. First seen from the north by Joseph Thomson in 1880, it was visited by Dr Kaiser, a German, in 1882, and has since been thoroughly explored by various British and German travellers.

See “Begleitworte zu der Karte der Gebiete am südlichen Tanganjika-und Rukwa-See,” by Paul Sprigade, in Mitteil. v. Forsch. u. Gelehrten a. d. deutschen Schutzgebieten (Berlin, 1904), with map on the scale of 1:500,000.