Temporal evolution of suspended solids in the management of medium-sized watersheds in the Metropolitan Region of Paraíba Valley

Abstract

The demand for water to meet the needs of the population has increased with the rapid growth of urban centers. The urban expansion in Taubaté (23.03º S, 45.55º W) negatively impacts the Una River Basin, a significant tributary of the Paraíba do Sul River, resulting in issues of sedimentation, siltation, and flooding. Systematic monitoring of sediment characteristics in human-influenced areas allows for an understanding of water quality variations, watershed diagnosis, and analysis of impacts on aquatic ecosystems, with total suspended solids (TSS) being a widely used parameter in this context. This study investigated the temporal evolution of the TSS concentration in the Una River, highlighting the importance of sound management practices to reduce sedimentation in urban catchments, through the analysis of biochemical parameters obtained from the Cetesb/Infoaguas platform. From 2008 to 2022, lower TSS concentrations were observed in winter (86.2 ± 35.6 mg L^-1), while higher values were obtained in summer (779.7 ± 1024.8 mg L^-1). In general, statistically significant correlations were found at the 95% confidence level between TSS and turbidity (Pearson's r = 0.93), dissolved oxygen (Pearson's r = -0.46), and electrical conductivity (Pearson's r = -0.43), while other evaluated parameters (pH, dissolved solids, and precipitation) did not show significant correlations. Among the key findings, it is crucial to study the temporal evolution of TSS and to implement sustainable management strategies in urban catchments, including erosion control measures and stormwater management, to preserve water quality, aquatic ecosystems, and water supply in the urban communities of RMVale.

Keywords: basin, management strategies, sustainable, total suspended solids.