INSTABILITY OF WATER-RESOURCES AND MANAGEMENT OF A PLANNED WATER-SYSTEM IN NON-SAHELIAN WEST-AFRICA

Having verified the decrease in surface water resources observed over the last twenty years in West Africa, changes planned for the Sassandr a basin, Cote d'Ivoire, are described. The methods used to generate tw o hundred year data series, the basis of previous studies, are present ed. The generated time series allow the development of long term worki ng patterns for cases similar to the climatic conditions pertaining be fore and since the drought of the late 1960s. The results demonstrate a clear drop in the performance of the water system, related to climat ic conditions experienced since the start of the drought. The conclusi ons drawn from the comparisons and analyses indicate that, if the pres ent conditions were to persist in West Africa, surface water resources would no longer meet needs which were identified and planned for on t he basis of data records presenting characteristics different from tho se currently observed. The frequency of failures would then become muc h greater, leading to a serious decline in the output of existing faci lities. Modifications made to the operation of the Buyo reservoir are also analysed.