The Metabolism of a Hydroelectric Reservoir Subject to Anthropic Action: A Case Study in Central Brazil

The analysis of aquatic metabolism allows making inferences from an ecological point of view on the behavior of lakes and reservoirs because of the contribution of organic matter and nutrients to the hydrographic basin. Such anthropic action in the aquatic and terrestrial ecosystem around Brazilian hydroelectric power plants is caused by organic matter and nutrients released into the reservoirs from fertilizers used in agriculture, domestic sewage, and livestock waste. Based on the fundamental concepts of hydro-biogeochemical processes, we propose a qualitative model using the causal loop diagrams tool to study the behavior patterns of a hydroelectric reservoir under constant influence of polluting loads from different sources in its contribution basin. The model was created to identify the systemic patterns that contribute to the impacts observed in the operation of the plant because of the quality of the water in the reservoir. We performed a case study of the reservoir of the Corumba IV hydroelectric plant, located in the Brazilian central region. Potential leverage points of the system for which intervention is recommended were mapped, giving insights into ways to mitigate some of the impacts identified.