Factors, forms, assessment and human impact on excess erosion and deposition in the upper Bregalnica watershed (Republic of Macedonia)
published: Jan 1, 2011
ArtNo. ESP023105501008, Price: 29.00 €
One of the major environmental problems in the Republic of Macedonia is accelerated soil erosion. According to the national soil erosion map, the average production of eroded deposits is 685 m3/km2/y, whereas in some regions this value is significantly higher (Djordjevic et al. 1993). One of the regions heavily affected by erosion is the Bregalnica river watershed, especially the upper part (1 124.7 km2) in the eastern part of the country. Steep slopes of terrain combined with soft rocks (schists on the mountains; sands and sandstones in depressions), erodible soils, semi-arid continental climate and sparse vegetation cover, give high potential for soil erosion. This potential was converted to powerful erosional destruction in numerous forms under direct and indirect human impact during the last millennium. Natural vegetation was significantly devastated by extensive forest cutting for ore melting in mediaeval times and excessive utilisation of wood for different purposes at a later point, as well as by overgrazing of pastures. As a result, the landscape in the upper Bregalnica watershed is largely transformed, representing a veritable system of rills, gullies, earth pyramids, landslides and huge badlands with characteristic amphitheatric forms, locally called “mel”. Implemented erosion models show a truly high average soil loss of about 1mm/y, with significant local differences between areas subjected to a greater or lesser degree of human impact. Because of enormous sediment loads, the Kalimanci reservoir, which was built in 1969, was filled up very fast and lost more than 13% from its storage volume of 127 million m3. As a consequence of such violent erosion, attempts to investigate and control these processes were made from the 1960s onwards, but only with partial success.