Variability and trends in observed average monthly, seasonal and annual flows in the Faleme basin, Senegal

Climate change, linked to global warming, acts directly on our natural environment, transforming it, and is accompanied by changes in the hydrological cycle. As a consequence, there is drastic reduction in available water resources due to the marked decrease in rainfall. In this study, we use the Mann-Kendall test to characterize the variability and trends of runoff in the Faleme basin over the period 1954-2014. The results of the analysis reveal a statistically significant downward trend in practically every month and in periods of high and of low flows. A trend was observed also in the years with low flow during which the periods of high and low flow were less noticeable. The Mann-Kendall test thus proved effective in identifying the negative trends of the flow in the Faleme basin.