Modeling of Aquatic Ecosystem Dynamics in a Run-of-River Reservoir in the Brazil

The maximum specific pollutant loads of nutrients and carbonaceous organic matter of the effluent-in an initially oligotrophic or mesotrophic state artificial run-of-river reservoir-should be studied in order to serve as a basis for future hydroelectric in tropical regions. Two different hydrological scenarios in the central tropical region of Brazil are analyzed; a historical and a synthetic one. The maximum specific load that the artificial run-of-river reservoir of a hydroelectric power plant supports is evaluated in order to meet the environmental limits defined by national resolution. An analysis of lateral and vertical dispersion between epilimnion and hypolimnion is performed. The maximum permissible loads for the historical hydrological scenario with a long-term average flow of 247.2 m(3) s(-1) are 70.017 kg BOD hm(-3) d(-1), 0.131 kg P-total hm(-3) d(-1), and 2.626 kg N-total hm(-3) d(-1). For the synthetic hydrological scenario with a long-term average flow equaling 140.4 m(3) s(-1), the maximum permissible loads are 55.576 kg BOD hm(-3) d(-1), 0.096 kg P-total hm(-3) d(-1), and 1.925 kg N-total hm(-3) d(-1). The proposal of this study is to provide an aid to the decision-making process of environmental managers and consultants in artificial run-of-river reservoirs in tropical regions with similar hydrological regimes.