Évolution Des Extrêmes Pluviométriques Dans La Région Du Gôh (Centre-Ouest De La Côte d’Ivoire)

The Gôh region located in western-central Ivory Coast is a region whose economy depends mainly on agriculture, which itself is dependent on the climate. Thus, variation and climate change has a significant impact on crop yields. The objective of this work is to study the evolution of extreme rainfall on rainfall station in the region (Gagnoa station). The calculation of rainfall indices was performed with the software RclimDex. It appears from this study has the Gagnoa station, five (5) of the seven indices calculated namely, the maximum rainfall of one day height (Rx1day), the maximum total rainfall of 5 days (Rx5daiy), the days very rainy (R95) extremely rainy days (R99p) and consecutive dry days (CDD) experienced an increase. While the total annual rainfall (PRCPTOT) and consecutive wet days (CWD) declined. In general, the GOH region is experiencing a decline in rainfall and therefore an increase in dry spells during the rainy seasons

Évaluation De La Vulnerabilite A La Pollution D'une Eau De Surface Destinee A L'adduction D'eau Potable D'une Metropole. Cas De La Lagune Aghein A Abidjan, (Sud De La Cote D'ivoire)

The lagoon that is the subject of this study, was chosen as drinking water alternative source of supply for the city of Abidjan. However, this language is shown in a very favorable area of forest to agriculture. We observe large rubber plantations, food and oil palm crops spread throughout the lagoon basin. Also, fertilizers injected into these plantations, as well as releases from industries and homes they are potential sources of pollution of the lagoon. According Humbert (2012), this pollution is reflected in particular by widespread concentration of nitrates and pesticides. Given these observed problems related to the quality of this resource, this study was initiated. Its objective is to develop a methodology based on the functionality of a Geographic Information System (GIS) to assess the degree of threat to what the Aghein lagoon faces through the completion of a vulnerability map at pollution. The method used here is a spatial analysis model incorporating several parameters including the slope, land cover, soil type, runoff and drainage density. These parameters have been previously defined, prioritized and weighted, and then integrated into a GIS. The resulting map shows five classes of vulnerability indices to pollution of the lagoon Aghein. They are: very small classes, low, medium, high and very high. These indices highlight the areas from which the lagoon is threatened

Evaluation de la Vulnérabilite à l’Inondation des Communes à Proximité des Grandes Villes Ouest Africaines : Cas de la Commune de Bingerville (Est d’Abidjan – Côte d’Ivoire)

Cette étude vise à mettre en évidence des zones potentiellement inondables ou à risque d’inondation dans la commune de Bingerville (à l'Est du district d’Abidjan) dans un contexte d’urbanisation rapide et non maitrisée, en vue d’une gestion intégrée et durable de son espace. La démarche méthodologique utilisée a consisté à combiner les techniques de l’analyse multicritère, et les systèmes d’informations géographiques. Cinq paramètres que sont: la pente, l’occupation du sol, la densité de drainage, la densité de population et les facteurs environnementaux enthropiques ont été utilisés dans cette étude. Ensuite, des poids ont été assignés à ces paramètres par l’application de la méthode d’analyse multicritère de Saaty (AHP). La carte de vulnérabilité, a été obtenue par la combinaison des cinq paramètres à travers un SIG, et elle révèle cinq classes (très faible, faible, moyenne, fort et très forte). Les résultats montrent que la commune de Bingerville est moyennement vulnérable à l’inondation. Cependant, certains quartiers situés principalement au centre de la commune et en zones périphériques et certains villages situés en bordure de lagune tels que Anan et Akandjè présentent de fortes vulnérabilités à l’inondation. Cette information scientifique oriente des prises de décisions par les autorités en charge de la gestion de la commune dans la prévention et la prise en charge des crises d’inondation.   This study aims to highlight potentially floodable areas or areas at risk of flooding in the town of Bingerville (East of the district of Abidjan) in a context of rapid and uncontrolled urbanization, for an integrated and sustainable management of its space. The methodological approach used consisted in combining the techniques of multicriteria analysis, and geographic information systems. Five parameters including slope, land use, drainage density, population density and anthropogenic factors were used in this study. Then, weights were attributed to these parameters through Saaty’s multi-criteria method (AHP). The vulnerability to flood was categorized into five classes (very low, low, medium, high and very high) by using GIS. The results show that the commune of Bingerville is moderately vulnerable to flooding. However, some neighborhoods located mainly in the center of the commune and in peripheral areas and some villages located on the edge of the lagoon such as Anan and Akandjé are highly vulnerable to flooding. This scientific information is used to guide decision-making by the authorities in charge of managing the commune in the prevention and management of flood crises. &nbsp