Multiple views on the sediment and water quality in the Barra Bonita Reservoir (São Paulo State): the weight of evidence

Abstract

Assessing the water quality of lakes and reservoirs is a fundamental step in active environmental management programs. In addition to the classic in-situ water sampling procedures proposed in this project, it is also interesting to apply other complementary approaches to on-site studies. This work aims to study the Barra Bonita reservoir (São Paulo), evaluating the quality of its waters and sediment, using multiple perspectives. Barra Bonita is an important reservoir located in the Tietê river basin, formed by its dam, and has the Piracicaba river as another important forming branch. For decades, the reservoir has compromised the quality of its waters and sediment. In addition to water quality studies with satellite images and thematic maps obtained with robust validated algorithms, using Sentinel 2 images, this research also includes complementary studies with surface and profile sediment collections, carried out at numerous stations collections distributed between the main arms and the central body. In the sediment, toxicity tests and analyzes of total and dissolved metals and benthic organisms will be carried out. In the water column, numerous quality parameters will be analyzed, such as pH, dissolved oxygen, nutrients, etc., and phytoplankton, zooplankton, phycocyanin and cyanotoxins. It is expected to observe a pattern, with the dam zone more lentic and less eutrophic, when compared to the upper part, the main rivers branches, and with the in-situ samplings to obtain a diagnosis of the ecological quality of Barra Bonita. It is also expected to confirm that the Tietê river branch is more compromised than the Piracicaba river branch. The multiple applied looks provide countless lines of evidence, which, when integrated, will offer a current and future scenario of the quality of the reservoir's water and sediment, in addition to proposing a discussion on how to reverse the observed situation, with an innovative approach in Brazil. (AU)