Soil erosion risk assessment on the territory of Botevgrad Valley area (West Bulgaria)

The mountainous and semi-mountainous nature of the relief on the territory of Botevgrad Valley (West Bulgaria) is a prerequisite for erosion processes with different intensity. The erosion is mostly hidden, in surface washing and removal of the fertile soil horizons. The degree of erosion in the area is low to moderate. The water erosion is represented as the annual average value of the amount of eroded soil through the Universal Soil Loss Equation (USLE) model integrated into the Geographical Information Systems (GIS). The estimated potential risk of water erosion on a main part (65.92%) of the land is very high. It was evaluated that potential risk can have values about 200 t/ha y eroded soil. The assessment of the estimated actual soil losses from water erosion in the Botevgrad Valley has a low actual risk (class 2). The estimated loss of eroded soil is about 3 t/ha y, which is typical for that region.