It seems probable that, in a period geologically not very remote, the " Albertine " system will consist of one great river, extending from the northern slopes of the Kivu range, where the Ruchuru has its rise, to the existing junction of the Victoria Nile with Albert Nyanza.
The agreement made Kivu entirely a Belgian lake.
North of Tanganyika the valley is suddenly interrupted by a line of ancient eruptive ridges, which dam back the waters of Lake Kivu, but have been recently cut through by the outlet of that lake, the Rusizi, which enters Tanganyika by several mouths at its northern end.
To the north-west end of Lake Kivu, thence across that lake near its western shore, and along the river Rusizi, which issues from it, to the spot where the Rusizi enters the north end of Lake Tanganyika; along the middle line of Tanganyika to near its southern end, when it is deflected eastward to the point where the river Kalambo enters the lake (thus leaving the southern end of Tanganyika to Great Britain).
As already indicated, the southern half of Victoria Nyanza and the eastern shores, in whole or in part, of Lakes Kivu, Tanganyika and Nyasa, are in German territory.
The western frontier coincides with part of the eastern wall of another depression, the Central African or Albertine rift-valley, in which lie Tanganyika, Kivu and other lakes.
On the 14th of May 1910 a protocol was signed defining the new frontier as follows: From the north end of Lake Kivu the Congo-German frontier turns east by north, traversing the volcanic region of Mfumbiro, and crosses the summit of Mt Karissimbi to the summit of Mt Sabyino, where the British, Belgian and German frontiers meet.
Mitumba range extends from the south-eastern frontier of the colony, in a north-easterly direction towards Lake Tanganyika, and northwards along the western shore of that lake past lakes Kivu and Albert Edward to Albert Nyanza, forming the western edge of the western or Albertine rift-valley.
It includes some of the volcanic peaks which, north of Lake Kivu, stretch across the rift-valley and attain heights of 13,000 and 14,000 ft.; Albert Edward Nyanza and part of the Semliki river; part of Ruwenzori, the so-called" Mountains of the Moon,"with snow-clad heights exceeeding 16,50o ft.
The colony also includes the western shores of lakes Tanganyika and Kivu (q.v.).
The Kagera, the largest and most important of the lake affluents, which has its rise in the hill country east of Lake Kivu, and enters the west side of the nyanza just north of 1° S., is described in the article Nile, of which it is the most remote head-stream.
Farther north the western depression, sometimes known as the Central African trough or Albertine rift-valley, is occupied for more than half its length by water, forming the four lakes of Tanganyika, Kivu, Albert Edward and Albert, the first-named over 400 m.
Other volcanic peaks rise from the floor of the valleys, some of the Kirunga (Mfumbiro) group, north of Lake Kivu, being still partially active.