RECENT EVOLUTION OF WATER RESOURCES IN THE SASSANDRA CATCHMENT AREA (COTE DIVOIRE) IN A CONTEXT OF CLIMATE VARIABILITY AND CHANGE

The objective of this study is to assess the impacts of climate change on the surface water resources of the Sassandra catchment area. This study conducted at the scale of the Sassandra sub-catchment areas took into account six (6) sub-catchment areas: Bafing in Badala, Boa in Vialadougou, Davo in Dakpadou, Lobo in Nibehibe, Nzo in Kahin and Sassandra in Semien. The methodological approach is based on the evaluation of the drying up coefficients, the duration of drying up and the volumes of water mobilized by the aquifers. All these parameters were estimated using Maillets law. The analysis of the different dynamics was carried out using the cumulative sums test. The results showed that the breaks in rainfall and the drying up coefficient were between 1982 and 2000, 1985 and 2003 respectively. After these breaks, the drying up coefficients increased (Bafing in Badala, Boa in Vialadougou and Davo in Dakpadou) from 17 to 25.9% and decreased (Lobo in Nibehibe and Nzo in Kahin) from 1.4 to 6.3%. A shortening of 3 to 5 days was observed on the Bafing in Badala, the Boa in Vialadougou and the Davo in Dakpadou. The volumes of water mobilized by the aquifers decreased on the Bafing in Badala, the Davo in Dakpadou and the Sassandra in Semien.While they increased on the Boa in Vialadougou, the Lobo in Nibehibe and the Nzo in Kahin.