Vulnerabilidade ripária socioecologica à jusante de barragens de rejeito em Minas Gerais

Abstract

The construction of dams is a vital part of the history of civilizations and currently plays a strategic role in human development. These structures contribute to water supply, recreation, animal watering, power generation, flood control, water quality control and sediment control. But the adverse effects of dam construction can also impact large proportions of ecosystems, where humans are an integral part. Acid mine drainage is one of the impacts related to tailings dams, but the rate of breakage of tailings dams much larger than the rate of breaking of conventional dams amplifies ecological and social impacts. The state of Minas Gerais is one of the federation units with the largest number of tailings dams, as well as the state that keeps records of most cases of disruption of these structures. The break of the Fundão’s tailings dam, for example, is considered the greatest socioecological disaster in Brazil's recent history. In addition to degrading hundreds of kilometers of aquatic ecosystems, this disaster also affects seriously the biodiversity and human populations in riparian habitats, which account for 19 deaths. The objective of the present study was to characterize the Socioecological Riparian Vulnerability downstream of tailings dams, based on analyzes in the databases of the Economic Ecological Zoning of Minas Gerais (ZEE­MG) and the Brazilian Institute of Geography and Statistics (IBGE), generating information useful to decision makers in meeting the precautionary principle. Ecological and social information has been aggregated into a Socioecological Riparian Vulnerability Index (IVRSE). The center of the rivers presented higher values in the IVRSE, compared to the analyses performed in riparian zones. The IVRSE provides a general description of the vulnerability conditions in rivers and riparian zones downstream of tailings dams. Notwithstanding the representation of the IVRSE in the same spatial scale of the official hydrography net of Minas Gerais facilitates its immediate application in risk management by the decision makers to compliance with the precautionary principle.