Water management of the Gabcikovo Scheme for balancing the interest of hydropower and environment

The Gabcikovo hydropower scheme on the Danube is located in the area comprising one of Europe's most unique riverine wetland ecosystems and one of Central Europe's largest ground water resources which receives the main part of its recharge from infiltration through the river bed. When Gabcikovo was put into operation by Slovakia in 1992, and the main part of the water was diverted away from the Danube and the associated river branch system over a stretch of approximately 30 km and a reservoir was created on the Danube, it obviously was a matter of serious concern requiring comprehensive environmental assessment studies. This paper describes a comprehensive modelling system integrating modules for describing the reservoir (2D flow, eutrophication, sediment transport), the river and river branches (1D flow including effects of hydraulic control structures, water quality, sediment transport), the ground water (3D flow, solute transport, advanced geochemistry), agricultural aspects (crop yield, irrigation, nitrogen leaching) and flood plain conditions (dynamics of inundation pattern, ground water and soil moisture conditions, and water quality). A few selected results from the model applications are shown.