Laboratoire des Sciences et Techniques de l'Eau et de l'Environnement (LSTEE), UFR des Sciences de la Terre et des Ressources Minières, Université de Cocody, B.P. 582 Abidjan 22, Côte d'Ivoire
Daily rainfalls as they reach a certain threshold, induce severe flooding in some township of Abidjan district during the largest rainy season. This paper focuses on defining and identifying of heavy daily rainfall threshold linked in flooding over the Abidjan district.
The heavy rainfall maximum and critical occurrence period ascertainment has been possible thanks to the likelihood occurrence (from 0 to 100%). Identifying heavy rainfall threshold related to flooding-causing started with classification and definition of precipitation recorded from 2012 to 2014 over all stations of Abidjan district with the percentile. Then, using the rainfall total sliding window technic helped finding a threshold amount inducing severe flooding.
The critical period rainfall and flooding occurrence (likelihood occurrence of 75%) start from May 27th to June 22th. Rainfall total sliding and past flooding analysis revealed a threshold amount precipitation around 100 mm. Henceforth, this threshold could helped forecaster offices by issuing advisories and warnings for flooding when precipitation expected, at any location of Abidjan district, is near or exceeds the amount of 100 mm.
The led study presents the current state of the quality of waters of the tablecloth of Bonoua as well as its situation towards polluting elements of anthropological origin (NO3-, Cl-, NH4 +). This tablecloth is more and more requested to cover the water requirements of the city of Abidjan, while its quality is felt (experienced) by the diverse sources of pollution which multiplied further to the urbanization and to the development of the agro-industrial cultures. To estimate the current subterranean quality of waters of this tablecloth a comparison and a follow-up of its physico-chemical parameters from 2001 till 2015 was realized. It was coupled with a multivariated statistical analysis to know the Analysis in Main Component (ACP) to determine the origin of mineralization, The methodology took into account on one hand the hydrochemical parameters which showed that waters are acid with a pH between ((4,2UpH and 6,88UpH, more important concentrations in nitrates (140mg / L) to Ahoutou