Medida de concentração de sedimentos e turbidez na Bacia Hidrográfica do Lajeado Grande, São Martinho da Serra (RS)

Abstract

With the large current debate around climate change, water scarcity worldwide and the controversy created by the conflicts arising from multiple uses of water especially during dry periods, and taking into account the problems caused by flooding, mudslides, landslides originated the lack of criteria for the occupation and use of slopes and their causes and social and economic consequences, it is emphasized how important the acquisition of historical hydrological data to feed, support, validate or invalidate studies and methodologies that contribute positively progressive in the management of resources. This work has the following objectives, through the instrumentality of an existing monitoring station to assess the validity of using measures of turbidity, as a tool to monitor the production of sediments in the basin of the stream Lajeado Grande in São Martinho da Serra to from readings and samples fixed and specific, seeking to establish a relationship between the turbidity readings with the results of the concentration of suspended sediments. For that, we installed a programmable sampler pumping level sensor, a turbidimeter snapshot data logger and a torpedo tube type integrator, all set in a metallic structure at a fixed point in the bed of the stream. These instruments have been regularly scheduled for collection and reading of data in the occurrence of rain events. As results were obtained several correlations between turbidity and suspended sediment concentration including: Css = 1,0649T 5,2001 with R2= 0,53 and Css = 0.972 T - 5.5754 with R2 = 0.84. Were also obtained various relationships between flow and turbidity, and then concluded as valid the use of measures points and fixed turbidity with the methodology used to monitor the production of sediments in the basin under study, and recommending the continuation of work and diversification of new methodologies for collecting and analyzing samples aimed at reducing the deviations of the result.