Proposição de ações sustentáveis e estratégicas para controle da proliferação de macrófitas aquáticas no reservatório carioca, Minas Gerais, Brasil

Abstract

The reservoirs are used for different purposes, mainly to generate electricity. Since its installation, there is a significant change in the balance of the environment, affecting ecosystems associated with river basins and anthropogenic activities. Eutrophication is a natural or artificial process of nutrient supply to bodies of water, causing an elevation of organic matter higher than the capacity of the depuration system. The main impacts of eutrophication are: reduction of water quality; mortality of aquatic biota and deposition of the bottom of the reservoir; and excessive growth of aquatic weeds. These aquatic plants have different functions such as: encouraging the recycling of nutrients; contributing to the chemical alteration of the water; a source of biomass of microalgae and a food base of herbivorous creatures. However, the excessive proliferation of aquatic weeds in a reservoir contributes to: damage to multiple uses; increasing trophic levels and silting; oxygen deficiency, changes in patterns of thermal stratification and solar energy absorption; and a decrease of pH of the water, in addition to also being a suitable substrate for the proliferation of various unwanted organisms and loss of other important factors for this ecosystem. There are several methods for partial removal and control of the proliferation of aquatic weeds. Thus, the aim of this study was to collect data that supports the implementation of more sustainable management strategies to control the proliferation of aquatic weeds in the Carioca PCH reservoir - MG, with a look at its drainage area and different human activities existing upstream from the reservoir. It was found that the largest deterioration factor of water bodies studied in the drainage area is associated with urban effluents. After data collecting, it was found that if there is no investment in the revitalization of the St. João River, integration of the users and its governance, some attitude in the control of aquatic weeds will be palliative and will have little significance over the years.