Évaluation des Séquences des Types de Sècheresse par Indicateurs et par Echelles Spatiales et Temporelles dans le Bassin de l’Oueme à Beterou au Benin

The watershed from Ouémé to Bétérou has alternated wet and dry periods. And in this climatic context increasingly disturbed by human activities, it is essential to analyze dry episodes at various time scales, spatial and by various indices.To achieve this objective, climatological data (daily and monthly rainfall, temperature, FTE) over the period from 1965 to 2012 were collected. The hydrological data, consisting of daily flows from the Ouémé River to the outlet of Bétou, over the period 1965-2012, are extracted from the DG-Eau database.The results of the analysis of the drought indices indicate that the basin recorded different degrees of drought over the period from 1965 to 2012. The basin experienced during the period from 1965 to 1990 three very dry years (1981, 1982 and 1987) and a year close to extreme drought (1983). Thus, the period 1980 to 2000 was the period of manifestation of important phenomena of drought with the year 1983 as the driest one in all the history.Areas at risk of drought are divided into three levels and vary from low to high level in the basin. The low risk sectors cover 25.55% of the study area and correspond to the immediate surroundings of rivers and also high rainfall areas such as Copargo, Kouandé. Medium risk areas cover 21.45% of the territory and extend mainly in the central part. High risk environments occupy 53% of the territory and concern almost all sectors of the basin