Suspended sediment measurements on laboratory experiments

• Autor(a) principal: Santos, Sofia Raquel Gonçalves dos
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/17341
• topic: Sedimentos suspensos; Ensaios laboratoriais; Transporte de sedimentos - Monitorização

The sediment transport processes in rivers and coastal zones are characterized by two types of transport: bed-load and suspension. The quantification of this transport is important, in the evaluation of the shoreline and rivers evolution in order to protect areas that could be in danger of erosion when extreme meteorological phenomenon’s happen. How to measure the suspended sediment concentration has been subject of many discussions during the last years. There are several methods to quantify it numerically, although all of them exhibit uncertainties in the results. This work, performed in the Laboratori d’Enginyeria Marítima (LIM) of the Universitat Politècnica de Catalunya (UPC), has as goal to understand why the results obtained from the Optical Backscatter Sensors (OBS) and the Transverse Suction System (TSS) in SINBAD project were distant. To do it, after perform three hundred and twenty nine tests, the experimental and calculation procedures to obtain the best OBS calibration curve were described. Then, the concentrations from OBS and TSS were compared with the real concentrations. In the end, the functionalities of the equipment’s involved in the calibration set-up, OBS applicability and trapping efficiency of TSS, were verified. The results showed that, an accurate fit of OBS data is obtained when the curve is divided in sections depending on the suspended sediment concentration, with different behaviours and fitted differently. This equipment was considered the most accurate, up to concentrations bellow the saturation situation of the sensor.