“…In sub-Saharan Africa, many authors have demonstrated, in the hydrometeorological series, a dry phase which began towards the 1970s. In this region, a decrease in several water budget elements has been noted: annual rainfall (Hubert & Carbonnel, 1987;Moron, 1994;Mahé & Olivry, 1995;Paturel et al, 1995Paturel et al, , 1997Servat et al, 1997Servat et al, , 1999Hubert et al, 1998;Tarhule & Woo, 1998); number of rainy days Servat et al, 1997Servat et al, , 1999Houndénou & Hernandez, 1998;Tarhule & Woo, 1998); heavy rainfall intensities (Houndénou & Hernandez, 1998;Tarhule & Woo, 1998); river flows (Sircoulon, 1987;Mahé & Olivry, 1995;Hubert et al, 1998;Opoku-Ankomah & Amisigo, 1998); lake levels (Sircoulon, 1987); and duration of rainfall season (Bello, 1998;Servat et al, 1999).…”