Influence of Sediment Transport on Flow Conditions in the Vidoca River Watershed, São José Dos Campos-Sao Paulo-Brazil (PAP014439)

Código

PAP014439

Autores

Iria Fernades Vendrame, Alessandra Machado da Cunha

Tema

Urban Floods

Resumo

The aim of this study is to analyze how the transport of sediments interferes with flow conditions in the Vidoca River basin, which has an area of 60.08 km2 and is located in São José dos Campos,State of São Paulo, Brazil. The urban growth process in the city, an industrialized area, has contributed to an increase in flood frequency. The Vidoca River, an important tributary of the Paraiba do Sul River has been subject to erosion along its sides, with losses of culverts and bridges over the three last decades. Flow and sediment transport data for the watershed did not exist, so it was necessary to acquire them. The hydraulic data were measured during 12 field campaigns, from 2010 to 2013 in two sections. The velocities of flow were measured using either a MLN-07 current meter, or a smaller current meter, the FP101-FP201, and the water levels were measured with staff gauges. Samples of suspended sediments were collected using USDH-48 and USDH-49 samplers. The particle size analysis of solid samples of the background material and the analysis of concentration of total solids were performed in Institute of Aeronautical Technology (ITA) laboratories. The data were obtained through monitoring of liquid flow (Qlíq), suspended sediment concentration (Css), precipitation (P), water level (h), topography, and particle size, which were used to obtain the discharge and the relationships for rating curve and sediment yield curve. The results showed that Senhorinha Creek, a tributary located in the upper watershed, presents supercritical flow for Froude numbers ranging from 2.05 to 0.8 in the upper stretches, provoking bank and bottom erosion, thus leading to an increase in the sediment transport. Discharge and water level data were analyzed to establish the rating curve; the discharge varied from 0.50 to 64.52 m3/s. The sediment yield curve showing liquid discharge flow and solid discharge flow presented a coefficient of determination equal to 0.94.