Landslide influence on turbidity and total solids in Cubatão do Norte River, Santa Catarina, Brazil

• Published in: Natural hazards (Dordrecht) 2011-11, Vol.59 (2), p.1077-1086
• Main Authors: Kobiyama, Masato, de Almeida Mota, Aline, Grison, Fernando, Nery Giglio, Joana
• Format: Article
• Language: English
• Subjects: Brazil; Civil Engineering; Cuba; Discharge; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Management; Exact sciences and technology; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Hydrogeology; Landslides; Natural Hazards; Natural hazards: prediction, damages, etc; Original Paper; Rivers; Sediments; Turbidity; Watersheds
• ISSN: 0921-030X; 1573-0840
• DOI: 10.1007/s11069-011-9818-4

The rainfall events that occurred in the Cubatão do Norte River watershed, Santa Catarina State, Brazil, in 2008, were characterized by both high intensities and amounts and triggered landslides in this watershed. The objective of the present study was to analyze the influence of landslides on the turbidity and the total solid concentration (TS) in this river using turbidity, TS, and river discharge data obtained from March 23, 2008, to June 11, 2010. The comparison between turbidity and discharge patterns implies that the landslide process was not continuous and increased the turbidity intermittently and irregularly. The sediment yield during the landslide occurrence was approximately five times higher than without the landslide, even though the discharges were similar. The turbidity/discharge relationship during the landslide occurrence was markedly different from that before and after the occurrence. The correlation coefficients between turbidity and TS showed that the landslide significantly changed the sediment yield in this watershed. The result indicates that sediment yield estimations at the watershed level should be treated more carefully when landslides occur.