Language: French with trilingual abstract in English, French, and Dutch
Despite their economic and scientific relevance, the hydrological balance of the East African Rift lakes has been poorly investigated. This study is based on a database assembling, on a monthly and annual scale, information on pluviometry, water level variations, drainage and output associated with the four lakes and their catchment. This database results from an important effort of compiling dispersed information which is stored by different hydrological stations and from scientific publications. The first part considers the mean monthly and annual balance of the four lakes and evaluates in a quantitative and qualitative way the role of four main components. The second part analyzes and interprets the inter-annual variations of the balance in order to define their main causes. The third part is based on the previous results and uses the sensitivity of the lake level for variations in the precipitation in order to compare historical variations of the lake level with corresponding climatic changes. Finally, proposals for refining and prolongating the study are made.