Precipitation and runoff in the Kouilou Niari watershed

With a surface area of around 55,000 km2, the Kouilou-Niari watershed is located in southern Congo (Brazzaville). Two types of modification have been detected in the interannual change in runoff. In the pre-1970 period, wet and dry periods were observed to follow each other, but not in synchrony with rainfall. And, in the post-1970 period, there has been a decrease in runoff synchronous with precipitation. In view of the analysis carried out on the flow classes corresponding to the degree of humidity, which shows the presence of dry and moderately dry years (1954, 1958, 1967, 1968, 1975, 1980 and 1982), the Kouilou-Niari watershed as a whole suggests the beginnings of climatic changes in runoff.