CARTOGRAPHIE DES POTENTIALITES EN EAUX SOUTERRAINES PAR L’UTILISATION DE L’ANALYSE MULICRITERE ET LES SIG : CAS DU DISTRICT DU DENGUELE (NORDOUEST DE LA CÔTE D’IVOIRE)

Fresh water availability in rural areas of Côte d’Ivoire is a key factor in economic development, improvement of people’s living conditions and keeping them in rural areas. The Denguélé district which is one of the driest areas of the country, experiences frequently the departure of is young population. These youngs people who constitute the working population leave their areas because they are short of economic equipment. The aim of this study was the mapping of groundwater potential so that population will be supplied with enough water of good quality. The adopted methodology consisted of three steps. The first step consisted on mapping the different criteria related to groundwater study using SRTM and Landsat data, water points and hydro-climate data ,the second one dealed with the weighting of criteria using multicritaria analysis (MCA) and the third step consisted to realize water availability, accessibility and potentiality maps

The Impact of Climate Change on Water Resource Availability in a Trans-Boundary Basin in West Africa: The Case of Sassandra

In the context of climate change in West Africa characterized by a reduction of precipitation, this study was conducted to evaluate the impact of climate change on water resources from now to the end of the 21st century in the transboundary watershed of the Sassandra River shared by Guinea and Côte d’Ivoire. Historical and future climate data of Representative Concentration Pathways (RCPs) 4.5 and 8.5 were projected with the Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model (RegCM4). The hydrological modeling of the river basin was carried out with the conceptual hydrological model, GR2M, a monthly time steps model that allows for the assessment of the discharge of the Sassandra River for each climate scenario according to the time periods 2021–2040 (Horizon 2030), 2041–2060 (Horizon 2050), 2061–2080 (Horizon 2050), and 2061–2080 (Horizon 2090). The results show a reduction in annual discharge when compared to the baseline (1961–1980). For RCP 4.5, the observed values go from −1.2% in 2030 to −2.3% in 2070 and rise to −2.1% in 2090. Concerning RCP 8.5, we saw a variation from −4.2 to −7.9% in Horizons 2030 and 2090, respectively. With the general decrease in rainfall in West Africa, it is appropriate to assess the impact on water resources of the largest rivers (Niger, Gambia, and Senegal) that irrigate the Sahelo–Saharian zone

Spatial assessment of nighttime anthropization in the Comoé National Park in Côte d’Ivoira (West Africa)

Protected areas play a crucial role in preserving biological diversity, providing ecosystem services, and regulating hydroclimatic processes. However, the environmental balance of these areas is increasingly under threat due to rapid population growth, high demand for natural resources, and the effects of global warming. To address this, sustainable management of protected areas is essential. This study aims to develop a methodology for monitoring and assessing levels of nocturnal anthropogenic aggression in the Comoé National Park (CNP) in Côte d’Ivoire. By using geospatial data from the Day/Night Band of the Visible Infrared Imaging Radiometer Suite (VIIRS/DNB), the study characterizes the nocturnal anthropization of CNP through the use of several indices. First, light reflectance density is used to identify nighttime light emission foci. Second, the lighted area density index (LADI) is employed to understand the nature of nocturnal activities taking place within CNP, as indicated by artificial light at night (ALAN). Finally, the light intensity index (LII) is used to evaluate the degree of influence of nocturnal anthropogenic activities on biodiversity. The study also found important activities through LADI and observed a high level of light pollution in CNP. Ultimately, the findings of this study indicate that there is a significant level of nocturnal anthropization within CNP, highlighting the need for effective management and conservation efforts in the area

Urban expansion of Korhogo City (Côte d’Ivoire) using gis and nocturnal remote sensing

Abstract Temporal data series of stable Artificial Lights At Night (ALAN) obtained from sources such as DMSP/OLS and VIIRS/DNB provide valuable insights into the dynamics of urban expansion. This study introduces a novel methodology for characterizing urban boundaries, which combines textural analysis utilizing the Co-occurrence matrix and urban surface delineation employing the Wombling contour detection algorithm. Applying this method to the city of Korhogo in northern Côte d'Ivoire, the findings reveal an irregular and gradual evolution of urban surfaces between 1992 and 2012, with a rate of change of 35 km2. However, starting from 2012, a rapid urbanization process is observed, continuing until 2020, characterized by an evolution rate of approximately 45 km2. Considering the significant urban expansion witnessed in the city of Korhogo, it is imperative to implement appropriate urban management strategies and measures for ecosystem protection

Spatio-Temporal Analysis and Water Quality Indices (WQI): Case of the Ébrié Lagoon, Abidjan, Côte d’Ivoire

For decades, the Ébrié Lagoon in Côte d’Ivoire has been the receptacle of wastewater effluent and household waste transported by runoff water. This work assesses the spatio-temporal variability of the Ébrié lagoon water quality at the city of Abidjan. The methodological approach used in this study is summarized in three stages: the choice and standardization of the parameters for assessing water quality for uses such as aquaculture, irrigation, livestock watering, and sports and recreation; the weighting of these parameters using the Hierarchical Analysis Process (AHP) of Saaty; and finally, the aggregation of the weighted parameters or factors. Physicochemical and microbiological analysis data on the waters of the Ébrié lagoon for June and December of 2014 and 2015 were provided by the Ivorian Center for Anti-Pollution (Centre Ivoirien Anti-Pollution, CIAPOL), and the concentrations of trace elements in sediments (As, Cd, Cr, Pb, Zn) were used. The aggregation of standardized and weighted parameters allowed the calculation of the Water Quality Indices (WQI) by usage for each bays of the lagoon. The results show that in both 2014 and 2015, the waters of the Ébrié lagoon were generally of poor quality for the different uses examined in this study (aquaculture, irrigation, livestock watering, and sport and recreation) with an accentuation in 2015. However, some bays of the lagoon have waters of dubious to satisfactory quality. This study contributes an improved evaluation of the Ébrié lagoon waters

Assessing the Hydropower Potential Using Hydrological Models and Geospatial Tools in the White Bandama Watershed (Côte d'Ivoire, West Africa)

International audienceAn assessment of hydropower potential at the watershed scale was conducted at the White Bandama Watershed (WBW) in Côte d'Ivoire (West Africa). The method used involves the application of a hydrological model [Soil and Water Assessment Tool (SWAT)] coupled with a Quantum Geographic Information System (QGIS), denoted as QSWAT, to assess the water resource availability and hydropower potential of streams and determine potential hydropower sites for future hydropower development in the watershed. Geospatial data about the topography, soil types, land use/land cover, weather, and discharge were considered in hydrological and hydro-geomorphological characterization of the watershed. Streamflow and climate data-enabled model operation and simulation of the hydrology of the watershed. The model performance and robustness were confirmed with the p-factor, r-factor , coefficient of determination R 2 , and Nash–Sutcliffe (NS) efficiency coefficient. The hydropower potential of streams was evaluated by considering the simulated streamflow and water head. A total of 22 future hydropower sites was identified, geolocated, and classified with an estimated total production capacity of 538.56 MW

Observed Changes in Rainfall and Characteristics of Extreme Events in Côte d’Ivoire (West Africa)

International audienceThis study evaluates how the characteristics of daily rainfall and extreme events in Côte d’Ivoire changed during 1961–2015 using the rain gauge observation network of the National Meteorological Service (SODEXAM). The results indicate that the northern and southern parts of Cote d’Ivoire experienced a change from a wet to a dry period, with cut-offs in 1982 and 1983, respectively. In the northern part, this dry period was marked by a decrease in rainfall intensity, the length of wet spells, and the contribution of heavy and extreme rainfall, as well as an increase in the number of rainy days and a decrease in the length of dry spells. Over the southern part, this dry period was marked by an increase in the maximum length of dry spells associated with an increase in the maximum 1-day and 5-day precipitation events. The western part of Côte d’Ivoire experienced a late cut-off from the wet to dry period in 2000; the dry period was associated with a decrease in the number of rainy days, rainfall intensities, and maximum length of wet spells. Changes in the central part of Cote d’Ivoire presented high variability, and trends were less marked, even though a cut-off from a wet to dry period was detected in 1991. This study shows that Côte d’Ivoire, which is located in a subhumid and humid region and has an economy dependent on agriculture (especially cash crops, which comprise 60% of the GDP), is experiencing dry spells that are increasing in frequency and length. Combined with deforestation to increase production, this situation could lead to desertification and compromise the sustainable development goals of the country. The contribution of heavy rainfall was found to increase during the last 15 years, increasing the overall risk of floods, especially in urban areas where city authorities and populations are not prepared, thereby threatening infrastructure and human security