The Mirim and Patos Lagoons form the largest lagoon complex in South America. Wind is one of the dominant climatic elements of circulation and water levels in the basin. Therefore, we aimed to better understand the effects of wind on the Mirim–São Gonçalo watershed by applying the MGB hydrological model and to assess whether it would produce satisfactory results for modeling. Various tests were performed to determine the best representation of the processes involved and the observed levels. The best results were obtained with the inclusion of sub-daily wind data in the simulation and also the downstream boundary condition by using the observed water level data at the sluice dam of the São Gonçalo channel. The results showed that the model could successfully simulate the levels and demonstrated the importance of including the wind when modeling the hydrodynamic processes of large lake environments.

The great flood of 1941 remains the most impactful and traumatic flood event in the history of Porto Alegre. This event was caused by a combination of heavy rainfall in the basin in the days prior to the peak of the flood, and the wind that occurred during the flood. However, the influence of wind on the maximum flood level, although frequently mentioned, is not well known. This is largely because there are no systematic data for wind speed measuring and direction in 1941. Therefore, the present work aims to estimate the discharge and the maximum flood level in the city of Porto Alegre and in other relevant points of the basin. using hydrological-hydrodynamic modeling and, from there, analyze the possible role of the wind during the flood, through the simulation of hypothetical wind scenarios. The results showed that the discharges and levels were represented reasonably well with the MGB model at several locations in the basin. In relation to the 1941 event and the scenarios created, the contribution of the wind to the peak of the flood was of the order of a few to tens of centimeters, showing its potential role despite the limitations of the model.

Knowing water behavior in a watershed is extremely important to manage its multiple uses adequately. One of the models that has been highlighted by several studies and strategies to diagnose and understand hydrological processes and, consequently, define multiple water uses, is the Large Basin Model (MGB). The Mirim-São Gonçalo watershed (MSGW), which is a cross-border basin that stretches over the extreme south of Brazil and northeastern Uruguay, has significant environmental, economic, political and social importance to the population that lives there. This study aims at applying the distributed MGB to the MSGW to describe hydrodynamic processes and fluctuation resulting from water levels by considering input and output in the system, natural and anthropic ones, based on the Water Exploitation Index (WEI) and the Water Commitment Index (WCI). Results show that the adapted MGB enabled to simulate hydrological-hydrodynamic characteristics in the MSGW when information on winds were inserted. Results of the Brazilian part of the basin were better due to the distribution of input data. Regarding multiple uses, both the WCI and the WEI clearly show that the Uruguayan part of the basin is in a comfortable situation, in contrast with the Brazilian part, which needs special and criterial care since its situation is more critical.

O processamento do couro gera grandes quantidades de efluentes que possuem elevadas concentrações de matéria orgânica, nutrientes e produtos químicos tóxicos. Diante da possibilidade de utilizar águas residuárias como um meio de cultivo de baixo custo de cianobactérias para a obtenção de bioprodutos em biorrefinarias, o objetivo deste estudo foi avaliar o potencial de cultivo da cianobactéria Aphanothece microscopica Nägeli em efluentes de curtume para produção de biomassa, bem como sua aplicabilidade no tratamento destes efluentes. Para isso, cultivos da cianobactéria foram conduzidos nos efluentes de um curtume, em um biorreator heterotrófico sob as condições de concentração celular inicial de 200 mg L-1, pH inicial 7,6, temperatura de 25 ºC, aeração contínua e ausência de luminosidade. Durante os estudos, foram realizadas análises da cinética de crescimento da cianobactéria no efluente e dos percentuais de remoção de demanda química de oxigênio, fósforo total e nitrogênio total Kjeldahl do efluente, após o cultivo. Os resultados obtidos indicaram a viabilidade do emprego da cianobactéria, em biorreator heterotrófico, para o tratamento de efluentes de curtume aliado à produção de biomassa, sendo registradas produtividade de 42,67 mg L-1 h-1 de biomassa e eficiências de remoção de 72,3% de demanda química de oxigênio, 94,7% de fósforo total e 51,9% de nitrogênio total Kjeldahl, após 36 h de cultivo.