Turbidimeter calibration and reliability analysis of the estimation for suspended sediment at a semiarid watershed

Abstract

One of the biggest challenges of the sedimentological studies is to understand the temporal variability pattern of suspended sediment concentration. Therefore, this study aimed to calibrate a turbidimeter by the re-suspension of sediments, to analyse the reliability of the estimation of suspended sediments concentration and to evaluate the sedimentological dynamics in a section of the Umbuzeiro River, Ceará, Brazil. The results showed that the calibration method by re-suspension of the sediments generated a representative equation for the estimation of the suspended sediments in the studied section. The reliability analysis showed that the concentration of suspended sediments estimated by the turbidimeter is reliable up to the turbidity of 409 NTU and a low reliability for measurements of turbidity above 689 NTU; the sediment yield in the river estimated by rating curve was twice the estimated by turbidity method.