Gabriela IOANA-TOROIMAC, Institute of Anthropology ‘Francisc I. Rainer’ of the Romanian Academy, Romania
Stelu SERBAN, Institute of Anthropology ‘Francisc I. Rainer’ of the Romanian Academy, Romania
One of the largest exploitations of gypsum in Europe is found in the vicinity of Kosava village, in north-western Bulgaria, on the right bank of the Lower Danube River. Gypsum galleries collapsed at the end of 1970s with dramatic effects in Kosava village. As a consequence, sand was extracted from the Danube riverbed and used to fill empty gypsum galleries and prevent another disaster in the region. In this context of in-stream sand mining, the aim of our study was to understand the evolution of the Danube River right bank and Kosava Island.
We analyzed satellite imagery to reconstitute the river bank, island contour, and land use. Satellite scenes were selected during the low-water phase of the hydrological regime to better detect fluvial processes. We were able to identify several phases of evolution of the Danube River bank. First, the bank was eroded downstream the island; overall the bank lost approximately 80 m of the maximum width. Then, the small channel between the island and the bank was anastomosed. On field, the bank appeared to be high, which suggested the river channel incision. Then, the vegetation recruited the bank. As a consequence, the water flow changed its pattern. On field, fine sediment was found, which indicated the low water velocity. This appears to be a typical evolution for riverbed incision on sand: the degradation was attenuated by slumped material (Castro and Thorne, 2019).
Ethnographic interviews and archive research helped to reconstitute the history of the gypsum factory and link the in-stream sand mining to the bank and land use transformations. Downstream, the village of Slanotran lost the beach and the low-cost leisure activity.
The case study of Kosava and Slanotran villages is demonstrative for unsustainable environmental practice: solving a geomorphological risk triggered hydromorphological negative effects downstream the river. This is also a confirmation of various human impacts on the Lower Danube River channel (WRI, 2019).
Mots clés : river|human impact|local community|diachronic approach
A103737GI