Université Félix Houphouët-Boigny d'Abidjan-Cocody, Unité de Formation et de Recherche des Sciences de la Terre et des Ressources Minières (UFR-STRM), Laboratoire des Sciences et Techniques de l'Eau et de l'Environnement (LSTEE), 22 Bp: 582 Abidjan 22, Côte d'Ivoire
The spatio-temporal dynamic of land use in the Bonoumin and Gourou watersheds, over the last three decades (1990 to 2020), were analysed using Landsat images (1990, 2005 and 2020), remote sensing and a geographic information system (GIS). The main objective of this study was to analyse the impact of changes in land use in these two watersheds on stormwater runoff, which is responsible for flooding in the study area. The methodology adopted consisted of first downloading the Landsat images, which were then pre-processed, before undergoing several processes, leading to the classification and analysis of land cover dynamic. Maximum likelihood supervised classification was applied. Thus, the results of this classification showed that over the last three (03) decades, the impermeabilised surfaces in the two watersheds, represented by the medium and highly densified urban areas, have increased significantly, unlike the vegetated surfaces, which have decreased significantly. The increase in impermeable surfaces reduces the capacity for water to infiltrate the soil and increases the amount of runoff. The results also showed that in recent years, the upper reaches of the Bonoumin watershed have come under considerable anthropogenic pressure. This means that in a few years time, there will be a sharp increase in the amount of runoff water in the lowlying areas of this basin, and therefore an increase in the risk of flooding.
Extreme flow events have had a significant impact on populations and their activities in recent decades. To reduce the impacts associated with their advent a analysis between extreme hydrological phenomena and climate variability is necessary. However, qualitative data accessing difficulties and explanatory variable definition of extremes hydrological phenomena limit extreme flows rate studies. This study proposes the analysis the variability of the floods and the low flows at the Bianouan hydrometric station. Thus, five (5) floods characteristics variables (QCX5, QXJA, F90p, F95p and F99p) and three (3) for, the low flows (VCN10, QJNA and F10p) were extracted daily flows from the Bianouan hydrometric station from 1 January1962 to 31 December 2005. The variability of these extremes has been studied by the trend analysis (linear regression) and of the stationarity (Pettitt and Hubert tests). The results show that for flood variables the negative trend is very significant and ruptures are observed in 1980. For low flow variables the negative trend is significant and the ruptures are observed in 1981. From this study, we can deduce that the ruptures observed in the rains and flows average in the end 1960s and early 1970s have affected later the extreme flows around the 1980s.
This theoretical article aims to make a state of the art on prospective studies applied to the dynamics of land use and the use of water resources. As a first step, it presents a general overview of prospective studies by providing a refined and consensual definition of foresight, by presenting a brief history of the evolution of prospective studies worldwide, by presenting the scenario method in prospective and the two big families of scenarios (exploratory or forecasting and normative or backcasting). In a second step, he tackles the question of the prospective study and the dynamics of the occupation of the soil and use of the soil. Thirdly, it presents prospective studies and water resources on a given territory.
The mining industry is a main sector for economic and social development of a country. However, this industry generates many negative impacts on human and biophysical environments. Located south-east of C
The workshop of the interdepartmental committee responsible for managing household waste in Abidjan (Ivory Coast) in 2007 showed that the landfill site should be chosen out of the coastal sedimentary basin to protect the groundwater of the Continental Terminal aquifer against pollution. Indeed, this aquifer provides the potable water to Abidjan populations and also assures uniformity of the price of water by the water company of the Ivory Coast. But, given the groundwater flow and the possibility of transfer of fluid between the discontinuous and continuous aquifers, is it possible that an activity taking place outside the coastal sedimentary basin of C
In Ivory Coast, the phenomenon of decline of water drilling is found in rural and urban areas in the crystalline and crystallophyllian basement. The sub-prefecture of the department Angoda Toumodi does not rest (55%). Although several factors such as the condition of equipment, operating conditions, power conditions, the lithological conditions, problems of monitoring of hydraulic and quality parameters, etc., may partly explain this phenomenon, a fundamental question needs to be asked: drilling decline is it not related to a bad implementation of drilling? Thus, this study aims to analyze the productivity of water wells in operation, implemented by the method geomorphic from geophysical measurements. The study area is sub-prefecture of Angoda which lies between longitudes 5