Geomorfologia da planície de inundação e hidrodinâmica da confluência Paraguai-Cuiabá: Pantanal mato-grossense, Brasil

• Autor(a) principal: Luz, Leandro Domingos
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/5352
• topic: Geomorfologia - Planície de inundação - Paraguai, Rio; Geomorfologia - Planície de inundação - Mato Grosso (MT) - Cuiabá, Rio; Sistemas fluviais tropicais; Hidrossedimentogia; Ciências Humanas; Geografia

The Pantanal is one of the largest wetlands on the planet and it presents complex geomorphological and paleoenvironmental evolution. In recent decades, it has been considerable progress in research on the physical characteristics of the Pantanal basin. However, the distal areas of the megafans and the plains formed along the Paraguay River still require further studies. This research aimed to characterize the geomorphology and hydrology of the confluence zone between the Paraguay and Cuiabá rivers in the northern portion of the Pantanal. The study area is located in one of the three hydraulic bottlenecks that characterize the hydrology of the upper Paraguay River and influence the dynamics of floods. Remote sensing, sedimentological and geochronological data were used to describe the geomorphological evolution of the lowland, and hydrosedimentary data to describe the transport and deposition of sediments in the actual lobe of the Cuiabá megafan, as well as 2D and 3D measurements of the flow at the confluence Paraguay; it was enough to understand the hydrodynamics during the hydrological regime. The geomorphological mapping allowed us to describe five units in the study area: i) Paraguay-Porto Conceição plain (PPPC); ii) ParaguayAmolar plain (PPA); iii) actual lobe of the Cuiabá megafan (LAMC); iv) actual meander belt of the Cuiabá River (CMAC), and v) actual meander belt of the Paraguay River (CMAP). The evolutionary model, based on geochronological data, established for the study area, proposes that the morphologies found in the flood plain were originated under humid Middle Holocene climate and that after ~ 3,000 AP. the Cuiabá river no longer presented a multichannel pattern and starts to build its meandering channel. The hydrological, hydraulic and hydrosedimentary study of the present depositional lobe of the mega-river of the Cuiabá river corroborates the importance of the distal zones of the megaleques for the sedimentation and water supply of the floods. In general, the values tended to decrease in the distal sections of megaleque, possibly reflecting the influence of the Amolar bottleneck. Finally, the study contributes to the understanding of hydrodynamics, morphological dynamics and sediment transport at the confluence of the Paraguay-Cuiabá rivers during the hydrological year. The dominance of the tributary (Cuiabá river) in the structure of flow, velocities and sediment transport, as well as the backwater effects produced in the main river (Paraguay river) was evidenced. Thus, the Paraguay-Cuiabá confluence has hydrodynamic behavior that has not yet been described in the literature