Spatial and temporal variability of climatic parameters and its effect on drying up in Débo and Bô catchments (Department of Soubré, south-western of Ivory Coast)

The present study deals with the spatial and temporal variability of the climatic parameters and their consequence on the drying up of streams Bô and Débo and on the refill of the ground-water sheet in Soubré area. Methodology used is articulated around the study of the hydrological assessment according to Thornthwaite in the two catchments, the study of the seasonal and interannual variability of the climatic variables and the study of drying up by the determination of the coefficients of drying up and the mobilized volumes as well as their evolution. The hydrological assessment reveals that evapotranspiration is very active in the area of Soubré and has particularly contributed to reduce water resources of the area. Indeed, on the totality of rainfall, only 5.24% joined the underground network to refill the groundwater. The evolution of the curves of drying up reveals that, in Débo and Bô catchments, drying up lasts in general between 30 and 160 days. The coefficients of drying up in the both watersheds knew a rise of 1983 to 1991. Since 1991 there has been a relative decline in these coefficients. Thus, the coefficients of drying up continued to increase in recent years inversely with volumes participating in the reduction of water resources in the area and affecting in a pejorative way the groundwater refill.