Discussion of methods and tools used to identify the incoming loads in reservoirs and their impacts in water quality

Código

II-FLUHIDROS0093

Autores

Lais Ferrer Amorim de Oliveira, José Rodolfo Scarati Martins

Tema

12 - Limnologia e modelagem da qualidade da água.

Resumo

Land use management plays a crucial role in the water quality plan and security. However, due to the unique characteristics of each place, a common management guideline is challenging, making accurate diagnostics a necessity. This study aimed to study methods and tools to perform an accurate diagnosis of incoming loads in reservoirs. The research used in situ monitoring and mathematical modeling in a mixed land-use watershed to point out the main sources of pollution and their variability, as well as their impact on the local reservoir's water quality. Autumn and spring have been pointed as critical periods for water quality, with a high load of pollutants entering the reservoir, mild water temperature, slower flow, and more transparent water, allowing light to penetrate deeper, thereby creating an ideal environment for microorganisms to thrive. As a result, organic matter degradation and algal growth increase, compromising the water quality. Elevated concentrations of phosphorus were found in both watershed and reservoir, which changed depending on the sanitation infrastructure implemented. Phosphorus behavior in the reservoir's water column was analyzed using a 3D mathematical model. During rainfall, phosphorus concentration showed peaks and valleys, indicating that rain as the driving force of its dynamic. This emphasizes the consequence of the sanitary conditions of the watershed, the contribution of nutrient washoff, the dependence on Phosphorus for algal growth and its impact on the reservoir's water quality. These conclusions demonstrate the need for an accurate diagnosis for assertive management of the watershed load.