Groundwater vulnerability map for the Ogosta River Basin, northwestern Bulgaria

The present paper deals with evaluation and mapping of the intrinsic vulnerability for the Ogosta River Basin in northwestern Bulgaria. The protective cover and infiltration conditions (PI) method is used developed within the scope of COST 620 Project. According to this method, PI factors are evaluated and groundwater vulnerability map is prepared. Groundwater in the karst basins is the most vulnerable to pollution. The alluvial deposits are classified as moderately vulnerable. The loess cover provides effective protection of groundwater against pollution and thus the respective areas are low vulnerable to pollution. The Neogene limestones, sands and sandstones are moderately vulnerable. Possible removing of the soil cover would result in high vulnerability of the respective aquifer. The prepared vulnerability map may be used for groundwater resource protection and land use planning in the Ogosta River Basin.