Flooding and flood water storage in karst systems of the Mediterranean region

Flooding is a recurring natural phenomenon that can have both life-giving and destructive aspects. In natural environments, floods are often an important element of the seasonal hydrologic cycle that provides water and nutrients to soil, supporting unique, rich and diverse ecosystems. However, flood events can also represent a destructive force that can endanger lives and cause significant damage in urban areas. Karst areas, in particular, are unique because of their special hydraulic characteristics in terms of flood occurrence, the dependence of ecosystems on such events, and attempts to actively store and manage floods. In this article, the hydraulic response of karst aquifers to heavy precipitation events, flood generation, and engineering interventions for flood control are discussed using several examples from karst areas in the Mediterranean region. Flooding mechanisms and regulatory structures in karst poljes are considered using several typical examples from the Dinaric mountain range. In addition, different variants of groundwater abstraction for increasing storage capacity and flood control are presented using examples from France and Montenegro. Managed aquifer recharge in karst areas and adjacent aquifers is demonstrated with examples from Jordan and Algeria. Finally, failed attempts at flood storage in karst reservoirs are presented with examples from Spain and Montenegro. These examples of flood retention in karst areas show the wide range of planning and technical measures and remind us of possible risks and failures in implementation as well as some positive and negative impacts on the environment and especially on ecosystems.