Hydraulic constructions and facilities on karst in Bulgaria: repercussions influence and problems

The safety and accident free exploitation of hydraulic facilities depends on geological and hydrogeological conditions of terrains where they are built. Such facilities have one of the most serious problems when they are located in a karst environment. In Bulgaria, there have been a number of cases of refusal to build dam walls at the preliminary exploration, as well as complication of the initial projects after clarification of the karst features in the affected areas. In many cases, after the construction of the facilities, changes are identified in the hydrogeological conditions which, besides the karst water regime, also affect the activity of the karst processes. Selected examples of hydraulic facilities on the territory of Bulgaria, the problems encountered, and the implemented engineering solutions are presented. The accomplished studies, construction and exploitation of hydraulic facilities in the karst terrains of Bulgaria are a serious experience that can be used in future similar activities.