Drought risk analysis applied to porous Swiss aquifers

The impact of hydrogeological drought on groundwater has been studied in the context of natural flow systems. The aim of this article is to find the relative resistance of 18 unconfined aquifer systems in porous media to a prolonged shortfall in recharge. A synthetic relative drought resistance indicator has been calculated for each of the aquifer systems based on 4 variables which are the half-recession time, the specific regulatory capacity, the drainage density and the aquifer system area. <br> The analysis shows that 33% of the chosen aquifer systems are weakly resistant. By contrast, 22% have a high drought resistance. The other aquifer systems are of moderate resistance (22%) or of good resistance (22%).