Evolution of runoff in the Nyong basin (South Cameroon)

The objective of this work is to investigate the effects of rainfall variability and anthropization on runoff in the Nyong River basin (Olama and Mbalmayo) and some of its sub-basins (So'o and Mefou) over the recent period. For this purpose, the hydropluviometric data of the basins concerned were analyzed using the Pettitt and Mann-Kendall tests. Similarly, the dynamics of the main land use patterns (LUC) of the basins for which certain changes in runoff seem to be linked to anthropization (Nyong to Mbalmayo and Mefou) could be assessed. This was done by means of supervised classifications based on the processing of Landsat satellite images of the basins studied on three dates. On an annual basis, rainfall has decreased statistically in general in the basins studied. In the large basins (Olama and Mbalmayo), this decrease in rainfall is synchronous with that of runoff, while it is concomitant with an increase in the Mefou (small basin).