Abstract: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 (1961)(1962)(1963)(1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974)(1975)(1976)(1977)(1978)(1979)(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.

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The objective of the research is to analyze the relationship between drainage and assisted navigation on the road. More specifically, to show how the drainage contributes to assisted road navigation. First, we extract the drainage of SRTM picture. In a second step, we integrated drainage and roads in a geographic information system (GIS). Finally, we processed in GIS, drainage and road network in order to highlight the characteristics of risk areas, construction sites of bridges, dams and computer aided navigation. The study shows that the drainage network and the road network integrated into a GIS leads to the production of an application that allows users and road managers to learn about the state of the road and help decision. The resulting application is an effective information on the state of the tool to help drive on-road driving and road network management.

An 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 R2, 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.

The valorization of crop residues could constitute an energy source (biogas) allowing to reduce the energy needs of populations in agricultural regions, improve their living conditions and slow down deforestation as well as greenhouse gas emissions. This work aims to determine the typology of agricultural waste in the departments of Soubré, Sassandra, Daloa and Issia, to determine the number of residues generated in these departments, and to assess the biogas potential of these departments said residues. Field observations were made to identify the different types of waste, then, based on agricultural statistical data from the Ministry of Agriculture and biogas productivity indexes, the quantities of agricultural residues and biogas were estimated. Agricultural residues consist of pods (50%), stalks (19%), cobs (3%), Straws (8%), stalks (2%), shells (9%), fibers (7%), husks (1%), and bunches (1%). In addition, these localities have 465266.3 t of pods, 173583.2 t of stalks, 84280.0 t of shells, 75,857 t of straws, 12,000 t of husks, 10,987 t of bunches and 6793.0 t of fibers. The departments of Soubré, Sassandra, Daloa and Issia contain a total potential energy of 235.87 × 10 6 m 3 of biogas. However, this is unevenly distributed among the localities. The volume of biogas recorded is higher in the department of Soubré (74.91 × 10 6 m 3 ) which is followed respectively by the departments of Daloa (62.27 × 10 6 m 3 ), Issia (52.77 × 10 6 m 3 and Sassandra (45.93 × 10 6 m 3 ). The departments of Soubré, Sassandra, Daloa and Issia have a very large potential for the production of agricultural residues that

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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.

This 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.