Cartographie des accidents regionaux et identification de leur role dans l'hydrodynamique souterraine en zone de socle. Cas de la region de Dimbokro-Bongouanou (Cote d'Ivoire).

This study aims to investigate a methodology to map regional discontinuities, based on a combined analysis of radar and optical images, to assess if they play a noticeable role as groundwater flow paths. This method is implemented in the region of Dimbokro-Bongouanou (Ivory Coast). In a first step, the methodological approach consists of spatial analysis of the regional lineaments likely to be related to the fracturing of the basement by means of combined analysis of radar (Radarsat) and optical (Landsat) images, and then validating these lineaments with the mean geological data. In the second step, analysis is proposed that enables the role of these lineaments in groundwater circulation to be identified. This consists of determining the correlation between the major lineament traces and the location of boreholes. The yield of boreholes is analysed as a function of their distance from the nearest lineament, which shows that borehole yield decreases proportionally with the distance between the lineament and high-yield boreholes (discharge greater than 5 m3/h). No correlation between distance to the lineament and low-yield boreholes (discharge less than 5 m3/h) is noticed. The negative correlation between the productivity of high-yield boreholes and the distance to the closest lineament confirms that these lineaments are surface traces of regional discontinuities and act as main groundwater flow paths. Citation Koita, M., Jourde, H., Ruelland, D., Koffi, K., Pistre, S. & Savane, I. (2010) Cartographie des accidents régionaux et identification de leur rôle dans l'hydrodynamique souterraine en zone de socle. Cas de la région de Dimbokro-Bongouanou (Côte d'Ivoire). Hydrol. Sci. J.55(5), 805–820. [ABSTRACT FROM AUTHOR]