Determinação do assoreamento do reservatório da PCH Cachoeirão

• Ano de defesa: 2013
• Autor(a) principal: Brito, Geanne Moreira
• Orientador(a): Azevedo, Roberto Francisco de
• Banca de defesa: Laquini, João Paulo
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Engenharia Civil
• Departamento: Geotecnia; Saneamento ambiental
• País: BR
• Palavras-chave em Português: Assoreamento; PCH; Batimetria
• Palavras-chave em Inglês: Siltation; PCH; Bathymetry
• Área do conhecimento CNPq: CNPQ::ENGENHARIAS::ENGENHARIA CIVIL::GEOTECNICA
• Link de acesso: http://locus.ufv.br/handle/123456789/3813

All reservoirs formed by dams are subject to the process of sedimentation. Sediment accumulation reduces reservoir s useful volume and causes modifications in its elevation x area x volume (EAV) curves, which must be periodically updated. In this context, this study aims to evaluate the siltation process in SHP (Small Hydropower Plant) Cachoeirão reservoir and to update its operational data. The methodology consisted of comparing the results obtained before and after the reservoir filling, using Digital Elevation Model (DEM) and the fuction TIN (Triangulated irregular network), allowing to generate the EAV curves and to identify the total volumes of sediment deposited in the reservoir and the sediment level in the water intake. From this comparison, it was determined that, during 13 years of operation, the volume of sediment deposited on Cachoeirão s lake was equal to 0.866 hm3. This value represents a reduction of 15.9% in the original storage capacity of the reservoir. The softwares Sediment and Dposit were also used to assess the siltation process in SHP Cachoeirão and their results indicated an underestimation of the deposited sediments volume, in comparison to field results. The sediments accumulated at the bottom of the reservoir presented a variable grain size distribution, ranging from sand size observed in particles deposited closer to the start of backwater, until clay size, observed in particles deposited near to the dam axis. The study also concluded that the expected useful lifetime of the reservoir should not be achieved, unless preventive measures are taken to reduce the amount of sediment that enters the reservoir.