Variabilité Pluviométrique Dans La Région De Katiola Au Nord De La Côte D’ivoire (Afrique De l’Ouest)

L’objectif de cette étude est de mettre en évidence, la variabilité dans les séries pluviométriques de la région de Katiola, située au nord de la Côte d’Ivoire. Pour ce faire, des données de pluviométrie couvrant la période de 1949 à 2013 ont été utilisées. La méthodologie adoptée est basée sur le calcul de l’indice pluviométrique de Nicholson, et des tests statistiques de détection des ruptures et tendance (test de Pettitt, test de tendance de Mann–Kendall). Les résultats obtenus indiquent que sur la période déterminée, les hauteurs pluviométriques annuelles oscillent entre 550 et 2000 mm avec une valeur moyenne annuelle d’environ 1107 mm. L’analyse du graphe de variation de l’indice pluviométrique de Nicholson, met en évidence l’existence de deux sous-périodes. D’une part, une sous-période humide de 1949 à 1968 avec un excédent pluviométrique de 13,16% par rapport à la moyenne et d’autre part, une sous-période sèche de 1969 à 2013, marquée par les indices pluviométriques les plus négatifs avec un déficit de 7,13%. La Méthode du test statistique de Pettitt appliquée à la série chronologique révèle une rupture à partir de l’année 1968. Les résultats obtenus confirment donc l’existence de variabilité et de rupture dans les séries pluviométriques de la région de Katiola depuis la fin des années 1960. The aim of this study is to highlight variability and breaks in the rainfall series from Katiola region located in the North part of Côte d'Ivoire. For the purposes of this study, rainfall data during 1946 to 2013 period were used. The methodology is based on the calculation of Nicholson’s rainfall index and statistical tests of breaks detected and for trend (Pettitt’s test and Mann Kendall’s test). The results obtained indicate that annual rainfall height varied between 550 and 2000 mm with a mean value of 1107 mm. Analysis of the variation curve of the pluviometry index shows two sub-periods, a wet sub-period from 1949 to 1968 with a rainfall excess of 13.16% compared to the average, and a dry sub-period from 1969 to 2013 with most negative rainfall index and a deficit 7.13%. Pettitt statistical tests applied to rainfall time series reveals a break from the year 1968 onwards. The results obtained confirm the existence of variability and break in rainfall series from Katiola region, since the end of 1960s year

APPLICATION DU MODELE INVERSE AUX INTERACTIONS EAU-ROCHE DANS LES EAUX SOUTERRAINES DES METAGRANODIORITES, SUD-EST COTE D’IVOIRE

In Ivory Cost, few studies have been performed on the process of water-rock interactions in aquifers of basement. The study aim is to provide, from an inverse model by usgs program “phreeqci”, orders of magnitude of the mass transfer from each mineral during the process of water mineralization in the aquifer of metagranodiorites. We use mineralogy and geochemistry of water and rocks. The mineralogical study indicated paragenesis of plagioclase-feldspar-chlorite-biotite and amphibole. Kaolinite is assumed to be the clay product of silicate minerals hydrolysis in the study area. The simulation provided dissolution rate of 8.3 10-4 mol l-1 for plagioclase, 1.7 10-4 mol l-1 for chlorite, 9.4 10-5 mol l-1 for biotite and 2.3 10- 5 mol l-1 for amphibole during water-rock interaction process occurred 15,000 years ago

ANALYSE DE LA PRODUCTIVITÉ DES AQUIFÈRES DE FISSURES DU SOCLE PALÉOPROTÉROZOÏQUE DE LA RÉGION DE KATIOLA (CENTRE-NORD DE LA CÔTE D’IVOIRE)

In the area of Katiola, the main part of groundwater resources is contained in the discontinuous aquifers of the paleoproterozoïc base.This study relates to the analysis of the productivity of the aquifers fissured of the area starting from an approach which takes into account the comparative analysis carried out on the one hand with the flows and physical parameters, flows and lithology, flows and transmissivity and, on the other hand an ACPN of these parameters.The various results contribute to known the hydrogeological potentialities of the area of Katiola. The depths most productive meets between 30 and 75 m. The section from 20 to 50 m of weathered material offer the best flows.67% of the flows met in the area are weak, that can be charged to the lack of studies before the establishment of the works.The most productive AE are located in the first 35 meters under the base of altérites.The schists are more productive than the granite

APPLICATION DU MODELE INVERSE AUX INTERACTIONS EAU-ROCHE DANS LES EAUX SOUTERRAINES DES METAGRANODIORITES, SUD-EST COTE D’IVOIRE

In Ivory Cost, few studies have been performed on the process of water-rock interactions in aquifers of basement. The study aim is to provide, from an inverse model by usgs program “phreeqci”, orders of magnitude of the mass transfer from each mineral during the process of water mineralization in the aquifer of metagranodiorites. We use mineralogy and geochemistry of water and rocks. The mineralogical study indicated paragenesis of plagioclase-feldspar-chlorite-biotite and amphibole. Kaolinite is assumed to be the clay product of silicate minerals hydrolysis in the study area. The simulation provided dissolution rate of 8.3 10-4 mol l-1 for plagioclase, 1.7 10-4 mol l-1 for chlorite, 9.4 10-5 mol l-1 for biotite and 2.3 10- 5 mol l-1 for amphibole during water-rock interaction process occurred 15,000 years ago