Análise do monitoramento do transporte de sedimentos em suspensão no trecho baiano do rio São Francisco.

Abstract

Regular hydrological monitoring is an inherent condition for the management of water resources, and the concentration of suspended sediments in watercourses is one of the monitored variables. In the Bahian section of the Sao Francisco River, four hydrosedimentometric stations are operated, as part of the operation of the National Hydrometeorological Network – RHN, with regular measurements of the concentration of suspended sediments . However, the objective of monitoring is not specific samples, but to obtain more discretized values of the continuous variation of solid discharge. From a regression of the measurement data to a curve representing the behavior of the concentration of suspended sediments as a function of the flow rate, the statistical analysis of the stations' historical series showed that this monitoring requires more strategic planning so these data can be better representative of the variation in sedimentometry throughout the hydrological cycle. The theory states, for example, that most of the solid load is transported during the rainy season, when measurements of suspended sediments should be concentrated. Furthermore, the transport behavior of suspended sediments changes throughout the flood, due to the dilution effect. Therefore, this study proposes a differentiated statistical analysis between the ascending branch and the descending branch of the flood wave. The generated rating curves provided estimated daily data on suspended solid discharge, whose series indicate that the period and frequency of these measurements need to be adjusted for moments of greatest inflection in the transport of suspended sediments