Groundwater and stone are intensively exploited in Wallonia (southern region of Belgium). The water table located in the mined geological formation might be reached when the quarry is deepened. Dewatering is therefore performed to depress the water table below the pit bottom in order to continue the activity in dry conditions. This affects the regional hydrogeology and the productivity of the nearby water catchments for the public distribution. In order to recommend an adequate feasibility study and minimize the impact on the environment, an interaction index, based on the equation used in the assessment of natural disasters, was developed.