The spatial distribution of rainfall and land use has important consequences for the hydrological and hydrogeological behaviour of a watershed. This study aims to better understand the impact of this distribution on aquifer recharge in the Bandama watershed. The spatialization of rainfall from isohyets, shows that it varies between 1200 mm and 1700 mm. The basin displays five (5) classes of land use that are: (1) dense forests, (2) open forests and / or savannahs, (3) shrub savannas, (4) bare soils and localities, and (5) water. The water balance shows that the excess which gives the surface flow and seepage is 348 mm upstream (Korhogo), and only 119 (Yamoussoukro) downstream. The total amount of water flowing over the Bandama basin at Yamoussoukro is 164.86 mm; which corresponds to an annual volume of run-off water of 4.338109 m3. The infiltrated water slide is 73.18 mm; which equates to an annual quantity of infiltrated water of 1.874109 m3.
This study aims the description of the geometry of the weathering profile and identification of areas of high aquifer potential of geological formations in the region of Sikensi-Tiassalé (south of Côte d’Ivoire). For this reason, the weathering profile models have been established for this region. These models were carried out from drilling data implanted in the study area. The formations in the basement have a vertical structure and a significant horizontal heterogeneity that is allocated to changes in facies. A succession of several layers is observed. Fractured and altered basement is observed in its upper part. Fractures are scarce with depth. Superficial formations overlying the basement have variable thicknesses: To the surface, there is laterite cuirass and topsoil, thicknesses between 0.5 and 3.5 m. Underneath the laterite, there is the sandy clay alterites of thicknesses between 5 and 40 m, in which one can identify horizons of allotérites and isaltérites. The water potential is important in the fractured base because all arrivals of water is only found in this part of the geological formations.
The current work aims to map the different forms of erosion which are expressed in the district of Attecoube. From georeferenced aerial photographs and based on the concepts of texture and structure, the different forms of erosion were discriminated on the screen. Many field visits, with tablets, GPS and tape measure (for measurements) allowed checking and adjusting the interpretations made on screen. These high-tech devices were also used for capturing images. Then, we superimposed the erosion forms map at the slopes map of the study area. Three main forms of erosion were revealed:
- diffuse erosion covers 14,32% of the study area;
- gully erosion which manifest itself on every slope range, covers 66.39% of the Attecoube district;
- mass wasting localised, cover only 06.82% of the study area.
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