LA SÉCHERESSE ACTUELLE EN AFRIQUE TROPICALE QUELQUES DONNÉES HYDROLOGIQUES

ABSTRACT

The drought of the period 1970–1973 in the tropical zone of Africa is analysed by the authors only for 1972 (or 1972–1973), they give attention to the yearly depths of precipitation and the observed discharges of the main rivers. This drought covered a very wide area which stretches from the Sahara Desert to the Equatorial area and crosses all the African Continent from West to East.

Precise data are given for the yearly depths of precipitation for the most representative stations, annual volumes of flow for the main rivers, maximum values of discharge and minimum values after the flood of 1972. Generally, the analysis of precipitation data as with the analysis of discharges leads to the conclusion that the return period of this drought is not far from 50 years. Some areas have been relatively little affected because the drought there has a return period of 10 years or even a return period of 3 years; on the other hand, others have been more severely affected, for instance Senegal and Mauritania with return period of 100 years.

It appears that no influence of man could be responsible for such a drought, at least as far as precipitation and discharge are concerned. It is not the same for the economic consequences.