ABSTRACT
ABSTRACT: This study is focused on the geostatistical assessment of the transmissivity of crystalline fissured aquifers in the Bondoukou region of north-eastern Cote d’Ivoire. In this region, few transmissivity data are available due to the lack of boreholes. Therefore, geostatistical methods were used to perform an estimation of this important hydraulic parameter over the whole region (2400 km2). The variographic analysis of this parameter shows that ‘raw’ transmissivity does not display any spatial structure. The logarithmic transform of the transmissivity (logT) is however a spatially structured variable. The use of the kriging method led to the estimation of logT over the whole study area. The geostatistics indicated a large nugget effect which indicates that the spatial correlation between individual boreholes is weak, even at short distances. This emphasises the importance of fractures in supplying these boreholes. Despite the lack of strong spatial correlation, the geostatistical procedure developed in this paper proved useful to understand variations in transmissivity. By including a large nugget effect, kriging has reliably reproduced the measured data and provided a tentative estimate of the transmissivity of the Bondoukou fractured aquifers.
