Systems models to evaluate eutrophication in the Broa Reservoir, Sمo Carlos, Brazil

The study of water quality in natural or artificial reservoirs has utmost importance to control eutrophication and for the development of projects with multiple uses. Through the study of energy diagrams of the reservoir and the hierarchy of factors that act on reservoir energy dynamics, management systems were proposed with the objective of maintaining water quality. The symbolic language of energy flows provides ways to compare diverse ecosystems, and enables an evaluation of the relative behavior of each component of the ecosystem. For these reasons, this study utilizes the energy systems language (ESL) developed by H.T. Odum to represent a reservoir as a dynamic system. Two models have been evaluated and simulated to evaluate eutrophication in the Broa Reservoir. The models were aggregated, macroscopic mini-models of the reservoir that retained the most important components and relationships. The first mini-model simulates the reservoirʹs daily metabolism and the second considers long-term phosphorus inflow. The models were tested with data from the Broa Reservoir. Results show that the use of ESL makes possible the construction of models that adequately represent structures and important functions of the Reservoir. Through the examination of these models, an understanding of the real ecosystem was facilitated.