ANALYSE DE PHENOMÈNES HYDROLOGIQUES DANS UN BASSIN VERSANT URBANISÉ: CAS DE LA VILLE DE YAMOUSSOUKRO (CENTRE DE LA COTE D’IVOIRE)

Abstract

This study focuses on the analysis of hydrological phenomena causing pollution landscaped lakes of Yamoussoukro city (Center of Ivory Coast). The methodology takes into account the analysis of climate variability (Pettitt test and graphical representation), water balance (Coutagne method, of Thornthwaite method and Tixeront-Berkaloff method) and comparative analysis using from potential evapotranspiration and real evapotranspiration on a monthly time. The results of this study were used to characterize the main manifestations of climate variability (1975-2009) observed for more than three decades in the region of Yamoussoukro. It appears from the study of the conditions of prolonged rainfall deficits have been identified before 1992. The post-1992 is characterized by a resumption of rainfall without reaching the heights of rainfall before 1970. Climate variability is manifested by a monotonic increase of air temperature. The water balance shows that the region receives an average of 1137 mm of rain annually and real evapotranspiration (ETR) is 853 mm, or about 74.98 % of the height of precipitated water. The infiltrated water slide is in the order of 70 mm or 6.15% of the height of precipitated water. The amount of runoff is in the order of 215 mm, or 18.87% of the height of precipitated water. The change observed on the cumulative heights rainfall was accompanied by a change in the duration of the rainy season. A trend towards shorter rainy seasons is demonstrated in the region of Yamoussoukro.