Soil erosion risk assessments for the Catchment of the Dzebelska River (East Rhodopes)

Soil erosion is recognized as one of the most serious soil threats in Bulgaria.The paper presents assessments of soil erosion factors and risk in the catchment of the Dzhebelska River (Eastern Rhodopes), Bulgaria.The assessments are based on the USLE approach, which was adapted for Bulgarian conditions and integrated with GIS.It is established that about 45% of the territory of the Dzhebelska River catchment are characterized with rains with an average erosivity between 600 and 800 MJ mm/ha h y.Largest percentage share (47%) of the lands in the catchment area is characterized by medium to high susceptibility to erosion (0.03-0.04 t ha h / MJ ha mm).Almost half of the lands in the studied catchment are with a slope above 15.Significant share of land (32.5%) is with high potential risk of erosion (100-200 t/ha y).Due to the largest percentage share of forestland (57%), lands with actual erosion risk below 3 t/ha y cover about 58 % of the catchment area, while these with a risk above 40 t/ha y cover about 15 %.