EROSIVE IMPACTS ASSOCIATED WITH THE COLÔNIA RIVER DAM: DIAGNOSIS AND SUSTAINABLE MANAGEMENT

Abstract

The construction of dams in tropical watersheds with a history of intensive land use represents a high-impact intervention, altering hydrological regimes and geomorphological processes. Although erosive impacts are recognized, integrated diagnoses are needed to consider the interaction between natural fragility and dam-induced changes to support sustainable management. This study analyzes the erosive processes associated with the Colônia River dam (Bahia, Brazil), integrating pedological and geomorphological information with the multi-temporal dynamics of land use. This descriptive and analytical research utilized secondary data, technical reports, and historical series from MapBiomas (1992-2022) to identify spatial patterns and trends before and after the reservoir's implementation in 2018. The data indicate a 3.8% reduction in pasture areas and a 4.3% increase in forest cover, composed of regenerating secondary vegetation. However, the predominance of erosion-susceptible soils (Ultisols and Cambisols) and the degradation of permanent preservation areas maintain the high erosive vulnerability of the basin. It is concluded that erosive processes result from the interaction between natural fragility and historical land use, intensified by the reservoir's operation, demanding environmental planning and conservationist actions to mitigate siltation.