A new concept for hard rock aquifers survey and management: individual blocks approach

The survey area is located south-west of Côte d'Ivoire in Precambrian metamorphic and plutonic zone. To highlight the network of kilometer-scale fractures in the base, remote sensing techniques were used. The map of lineaments obtained after processing of satellite images discretized the study area into blocks aquifers. This is a new approach in the study of the circulation of groundwater in hard-rock which allows going from a regional view to a local scale. The blocks were delimited by opened or clogged fractures that can have a conducting or watertight function, even a capacitor role. Statistical and fractal analyses of the geometric block parameters showed that those ones revealed the connectivity degree and the importance of the small fractures (fissured layer) in groundwater flow in hard-rock. This report is confirmed by high yields observed in the small blocks.