Extreme water related phenomena behaviour in Karst regions in past and recent time

The Karst covers approximately 20% of the global ice-free continental land. There is still a lack of an understanding of the scientific connotation of the karst critical zone as well as a lack of reliable explanations of dangerous water related phenomena in it. A wide range of closed surface depressions, a well-developed underground drainage system, and a strong interaction between the circulation of surface water and groundwater typify karst areas. It represents terrain with distinctive hydrogeology, hydrology and landforms arising from a combination of high solubility and well-developed secondary porosity. Any karst system shows the extreme heterogeneity and variability of geologic, morphologic, hydrogeologic, hydrologic, hydraulic, ecological and other parameters in space and time. In different karst regions extreme water related phenomena will manifest in different ways. Human intervention, especially construction of dams and reservoirs, as well as interbasin water transfer through long tunnels and pipelines can introduce instantaneous, definite and hazardous change. Karst represents an extremely vulnerable natural environment. During the last few decades flash floods have constituted one of the deadliest and costliest natural disasters which can occur almost everywhere in the world. Main topic of the paper should cover the following aspects: 1) A historical review of extreme water phenomena (drought, floods, wildfires, low groundwater levels, water pollution, landslides, sinkhole collapse, sea water intrusion etc.) in different karst regions; 2) Recent extreme phenomena with special reference to record breaking floods and droughts; 3) Are there differences between extreme water behaviour in karst regions in past and recent time?; 4) Natural versus man made influence on extreme water behaviour in karst areas; 5) Extreme water behaviour in urban areas developed in karst areas; 6) Karst flash floods as especially dangerous and very frequent extremely dangerous phenomenon in recent decades; 7) Case studies of anthropogenic actions on increasing risk of catastrophic repercussions in karst terrains; 8) Climate changes influence on appearance of extreme water related catastrophic events; 9) Earthquakes in karst area; 10) Karst surface collapse, debris flows, landslides, water inrush etc.; 10) Risk analyses particularities in karst terrain; 11) Sea water intrusion in coastal karst areas; 12) Environmental and social risk in karst areas caused by extreme water related phenomena.

Keywords: Karst Hydrology and Hydrogeology; Karst Flash Flood; Drought in Karst Areas; Karst Collapse