Historical Fluctuations of Lake Victoria and Other Lakes in the Northern Rift Valley of East Africa

Abstract

This paper describes the fluctuations of Lakes Victoria, Stefanie, Turkana and Naivasha over the last two centuries. A chronology of Lake Victoria back to 700 A.D. is also developed. These chronologies are based mainly on oral traditions of the local peoples, as described in various historical sources, and on reports of European visitors, settlers and explorers. In some cases actual historical levels have been reported. The historical fluctuations are meshed with the modern record to provide a picture of the fluctuations in lake levels until the late twentieth century.

The chronologies for Victoria and Stefanie contain much new material, permitting higher temporal resolution and better quantitative assessments, as well as extension of chronologies to the beginning of the 19th century. For Lakes Turkana and Naivasha, chronologies published by other authors are expanded and compared with those for Victoria, Stefanie and other African lakes. A long term chronology for Lake Victoria is developed using the record of the summer Nile flow.

These lakes show remarkably similar trends. The most important of these trends are low levels during the first half of the 19th century, very high stands in the last decades of the 19th century, and around the turn of the century a rapid fall to 20th century levels. The lakes returned to relatively high stands in the 1960s, but these generally ended in the 1970s.