One century of Senegal river annual discharges

The discharges of the Senegal River, the catchment area of which is 218 000 km(2) at the Bakel gauging station located on the Malian-Senegalese border, integrating the climatological conditions of a wide West African region, have been measured since the beginning of the 20th century. Thus, we now have a century-long time series, partially reconstituted as the river discharges have been influenced since 1987 by the Manantali Dam operation. The segmentation procedure-previously applied to a shorter time series-was applied to the 1904-2003 time series. Originating from the study of the pluviometric abrupt change observed in West Africa at the end of the 1960s, the segmentation procedure can be seen as a stationarity test enabling one to determine whether or not a time series is homogeneous (stationary) and, if not, whether it can be cut into stationary segments. This procedure has been applied in an original way, by investigating all sub-series beginning in 1904 and all sub-series finishing in 2003. This analysis, which studies the neighbourhood of the two extremities of the series, shows the pluviometric jumps already observed in the previous studies, but also shows a new positive jump between 1993 and 1994 which appears, at least for the Senegal River catchment, as the end of the drought which began at the end of the 1960s.