Simulation of the Dynamics of Land Cover and Land Use in the Lobo River Watershed Upstream of Nibéhibé(Center-West of Côte d’Ivoire)

From medium-resolution satellite images (Landsat TM, ETM+ and OLI), the spatial dynamics of land cover and land use are highlighted. The objective of this study is to quantify the evolution of land use in the watershed of the Lobo River upstream of Nibéhibé between 1986 and 2019 in order to analyze the impacts of human activities on the landscape. The study method was based, on the one hand, on the processing of satellite images, for the analysis of the dynamics of land use and, on the other hand, on the CA-Markov model, for the prediction of land use by 2050. It emerged from this study that the land use maps produced made it possible to highlight the spatio-temporal dynamics of land use on the basin. For the period from 1986 to 2019, there is a decrease in the area of forests in favor of built-bare ground and crops and fallows. A land use scenario for the years 2019 and 2050 was simulated with an accuracy of 87.11%. The regressive trend in forests seems to continue in the future with current land use practices.

Exploitation of Satellite Data for the Mapping of Areas at Risk of Flooding in Grand-Bassam (Côte d’Ivoire)

In order to better identify spatially the areas at risk of flooding for the riparian populations of Grand-Bassam during strong floods, a study aimed at developing hazard and vulnerability maps from RADAR Sentinel-1 and optical images Sentinel-2 has been put in place. The flood hazard study highlighted the flooded areas in Grand-Bassam. These areas represent 747.7 ha, or 1.02% of the total surface. The vulnerability map produced using the maximum likelihood method identified eight (8) land use classes. These are the classes Water, Dense forest, Secondary forest, Swamp forest, Industrial crops, Food crops, Habitats and bare soils. It made it possible to highlight the socio-economic interests of Grand-Bassam. The flood risk map developed from the intersection of the themes of the vulnerability map and that of the hazard has enabled the recognition of risk areas which are located near the source of the risk (Comoé River) and at low altitudes. These are Moossou, Petit Paris, Quartier Phare and Quartier France.

Land Use Dynamics in the Department of Séguéla, Northwestern Côte D’Ivoire

Land use monitoring occupies a very important place in the analysis of the dynamics of the earth system. It helps to understand the organization and helps to provide relevant elements for the establishment of diagnoses and the development of environmental forecasts. The objective of this study is to follow the evolution of the agricultural landscape in the department of Séguéla from 1988 to 2020 and to make a prediction for 2050, in order to manage the spaces reasonably. The methodology adopted is based on the one hand on the processing of satellite images for the analysis of land cover and on the other hand on predictive modeling (LCM model) by 2050. The results obtained show that the land use maps produced after processing the satellite images made it possible to highlight the dynamics of the agricultural landscape in this part of the Worodougou region. During the period 1988 to 2020, we witness an increase in the area of cultivated territory as well as a slight reduction in wooded savannas which are largely made up of perennial crops (cashew trees, cocoa trees, coffee trees, etc.). These two aforementioned classes have respective annual rates of change of 2.42% and −0.44%. A scenario modeling land cover changes in 2050 with an overall accuracy of 80.35% revealed a continued growth of crops and fallows to the detriment of natural forests and wooded savannas.

Mapping of Potential Recharge Areas of Fractured Aquifers in the Departments of Yamoussoukro and Toumodi (Central Côte d’Ivoire)

Groundwater is an important natural resource for all human activity. Today, due to climate change and population growth, the demand has increased considerably, thus requiring their evaluation to ensure sustainability. However, one of the important but difficult to estimate parameters due to its variability is the recharge. This work aims to map the potential recharge of aquifers in the departments of Yamoussoukro and Toumodi. Saaty’s AHP (Analytical Hierarchy Process) multi-criteria analysis technique was used by integrating different thematic layers. First, a reclassification then weighting of these parameters was made according to their influence in the recharge process. Finally, they were integrated into a GIS to produce the map of potential groundwater recharge zones. The results indicate that the potential high recharge areas represent approximately 43.11% of the area of the study area. These areas appear scattered in the sub-prefecture of Yamoussoukro, Kokoumbo Attiegouakro, Toumodi et Kpouèbo.

Mapping of Groundwater Potential by Multicriteria Analysis: Case of the Departments of Yamoussoukro and Toumodi (Central Cote d’Ivoire)

This study focuses on the problem of access to drinking water in the fractured areas of the departments of Yamoussoukro and Toumodi. The problem has become more acute since most of the boreholes drilled have failed. The main objective of this study is to map the areas that are favorable for the installation of large boreholes in the departments of Yamoussoukro and Toumodi in order to increase the population’s drinking water needs. Hydroclimatic and cartographic data, technical surveys of boreholes and satellite images were used to conduct this study. The AHP multi-criteria analysis method was adopted. It consists in aggregating the criteria by weighting and allowed to combine these different data to generate maps of groundwater availability, accessibility and exploitability indicators. These different indicators were then considered as criteria and combined using the full aggregation technique to produce the water potential map. These results show that the study area has significant groundwater reserves with nearly 63% of these areas being favorable for the establishment of large flow boreholes. This study provides some answers to the question of groundwater resources and could be used as a decision support tool in the execution of groundwater collection works in the departments of Yamoussoukro and Toumodi in order to avoid the high percentage of drilling failures encountered in past projects.

Assessment of Vulnerability to Groundwater Pollution in the Lobo Watershed at Nibéhibé(Central-West, Côte d’Ivoire)

Drinking water supply to people in rural areas is increasingly oriented towards the search for groundwater. However, these resources, which were once of good quality, are currently threatened by various sources of pollution points and diffuse. The objective of this study is to map the intrinsic vulnerability to groundwater pollution of the Lobo watershed in Nibéhibé. The intrinsic vulnerability mapping method, PaPRIKa adapted or PaPRI which acronym is the protection of aquifers (Pa) based on three criteria: P for protection, R for rock type, I represents infiltration was used. The results show three (3) vulnerability classes, which are moderate, high and very high. This map shows that the high vulnerability class (89%) dominates the study area. This predominance shows that the groundwater of the Lobo watershed is at high risk of pollution.

Impact of Meteorological Drought on Streamflows in the Lobo River Catchment at Nibéhibé, Côte d’Ivoire

The management of water resources in watersheds has become increasingly difficult in recent years due to the frequency and intensity of drought sequences. The Lobo River catchment, like most tropical regions, has experienced alternating wet and dry periods. These drought periods have a significant impact on the availability of water resources in the basin. The objective of this study is to analyse the impact of meteorological drought on flows in the Lobo River catchment. Therefore, using the Normalized Precipitation and Evapotranspiration Index (SPEI) and the Drought Flow Index (SDI), the characteristics of droughts were studied. The results of this study show that meteorological droughts were more frequent than hydrological droughts in the Lobo River watershed. However, the hydrological drought was longer and more intense than the meteorological drought. The greater relationship between meteorological and hydrological drought was observed at the Daloa and Vavoua station (0.43 < r < 0.50) compared to the Zuenoula station (r < 0.5). In addition, there was a resumption of precipitation and runoff between 2007 and 2013 in the basin. The study of these climatic trends would be very useful in the choice of management and adaptation policies for water resources management.