engleski

Karst Transboundary Aquifers: Challenges for Management

The karst has very different characteristics than all other environments. Water circulation in karst is more heterogeneous than in non-karst areas. Karst terrains show strongly different hydrological and ecological characteristics than non-karst terrains. One of the main characteristics of karst water circulation is strong interaction between surface water and groundwater and high and fast oscillations of groundwater levels in karst (often hundred or more meters during few hours). Conditions for water circulations and storage in karstified medium are strongly dependent on space and time scales. Precise catchment area is the essential information which serve as a bases for hydrological and water resources management purposes. In karst landscape the definition of catchment area and boundaries is a difficult and complex task, which very often remains unsolved. The catchment areas in karst may vary with variation in groundwater levels, i. e. change with time. Heavy rainfall causes fast and high rising of groundwater. Very often fossil and inactive channels and springs are activated, causing the interbasin overflow and/or large and instantaneous redistribution of the catchment areas. Human intervention, especially construction of dams and reservoirs as well as interbasin transfers through long tunnels and pipelines can introduce instantaneous and distinct changes in catchment areas and boundaries and by this way in hydrological, hydrogeological and ecological regimes. Due to the above mentioned reasons the most precise models and/or approaches in karst are only temporally valid. For karst surface water and groundwater management, water crises are increasingly serious all over the world. In karst terrains man’s interventions very often are uncontrolled, and result in hazardous consequences. In cases of transboundary shared karst surface water and groundwater catchments they can be a trigger for serious international conflicts. Due this reason water resources management in them is very complex and hardly predictable. The case of the Trebišnjica River catchment, which is internationally shared between Croatia and Bosnia-Herzegovina, will be described in detail. There are some large projects (tunnels, hydroelectric power plants etc.) planned to be constructed by both countries. Consequences of Croatian and Bosnian and Herzegovinian projects will change hydrological, hydrogeological and ecological regime in a very complex and not enough known transboundary karst aquifer system of the Trebišnjica River. These changes could open serious problems in water management between two neighbouring countries which shared the Trebišnjica River catchment. Karst catchments and aquifers display the extreme heterogeneity, variability and vulnerability of their hydrologic, hydrogeologic, hydraulic, ecological and other characteristics in time and space. Such complex systems need careful interdisciplinary co-operation among numerous experts in the broad field of karstology.

karst aquifer; karst catchment; interbasin overflow; karstology

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