Navegando por Assunto "Sediments"
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Item Acesso aberto (Open Access) Análise da influência do uso e ocupação da terra na concentração de sólidos em suspensão em reservatório hidrelétrico com o uso do sensoriamento remoto(Universidade Federal do Pará, 2022-07-09) SOUZA, Fabíola Esquerdo de; SOARES, Carlos Benedito Santana da Silva; http://lattes.cnpq.br/9153957633685323; ISHIHARA, Júnior Hiroyuki; http://lattes.cnpq.br/3498874642887006; https://orcid.org/0000-0002-0081-7913The use of remote sensing in reservoir sediment monitoring is important for temporal spac knowledge of sediment deposition in dam structures. In this context, this research was developed in the hydrographic basin that covers the Tucuruí HOU reservoir, in which suspended sediment concentration data from the M1 monitoring station located at 2 km upstream of the dam were acquired, and were integrated into the analyses to understand the relationship between the responses of satellite images and field measurements. Sediment analyses were performed with 14-year time series of MODIS images, composed of 8 days. Surface reflectance estimates were calculated using simplinear regression and coefficient of determination (R2). For the use and occupation of the land of the hydrographic basin, a temporal analysis of Landsat-5, Landsat-8 OLI/TIRS images was performed. Next, the land use and occupation were related to water quality analyses of stations upstream 1 (M1), Amount Repartimento (MR) and Montante Pacurui (MP). The results show that the calibration curve generated the linear regression equation with good fit for MI monitoring station, presenting efficiency in the data estimated by reflectance through this model. The analyses of land use and occupation show that over the years there was a reduction in forest formation and at the same time pasture growth occurred. In relation to water quality, the impacts caused by anthropic actions have negative influences. Thus, it is possible to observe the relevance of the use of remote sensing techniques, geoprocessing and geotechnologies, as instruments that help in the planning of land use and occupation, in the analysis of water quality and management of water resources in reservoir regions, since these technologies enable greater spatial scope of the analyses with lower costs.Item Acesso aberto (Open Access) Chemical composition of phytoplankton from the estuaries of Eastern Amazonia(Instituto Nacional de Pesquisas da Amazônia, 2014-12) VILHENA, Maria do Perpétuo Socorro Progene; COSTA, Marcondes Lima da; BERRÊDO, José Francisco; PAIVA, Rosildo Santos; ALMEIDA, Pryscila DenisePhytoplankton is important bioindicator of chemical and biological modifications of natural ecosystems. The objective of this study was to determine the total chemical composition of the phytoplankton of the Pará and Mocajuba estuaries on the eastern coast of the Amazon region in the Brazilian state of Pará. The chemical composition of the surface water, bottom sediments (total sample and bioavailable fraction), and the phytoplankton were determined by inductively coupled plasma optical emission spectrometry. Phytoplankton contained high concentrations of Ca, P, Mn, Fe, Zn, Al, Ba, and Pb. The phytoplankton of the Mocajuba estuary is rich in Fe (2,967-84,750 µg g-1), while those from the Pará is rich in Al (1,216-15,389 µgg-1), probably reflecting divergent anthropogenic inputs. Both samples indicated a high bioconcentration factor derived from both the water and the bioavailable fraction, reflecting the efficiency of these organisms in the concentration of metals.Item Acesso aberto (Open Access) Hidrodinâmica, transporte e proveniência sedimentar no baixo rio xingu e sua importância como “Tidal River” amazônico(Universidade Federal do Pará, 2022-07-14) MEDEIROS FILHO, Lucio Cardoso de; LAFON, Jean Michel; http://lattes.cnpq.br/4507815620234645; ASP NETO, Nils Edvin; http://lattes.cnpq.br/7113886150130994This research is based on the investigation of the processes (geological and hydrodynamic) that govern the recent evolution of a large tributary of the lower Amazon, the Xingu River. The aim was to investigate its aspects of sedimentary evolution and hydrological flows, from already consolidated data on the filling of its ria and how its patterns of transport and sediment trapping, its seasonal and tidal effects have been established, in addition to understanding the role of the Amazon River as a regulator in the dynamics of its tributary. Hydrodynamic measurements of flow, velocity and water level along with bottom sediment and MPS samples were collected at 3 annual seasons (February, June and November). The results provided support for the investigation of the Xingu-Amazonas interaction and the evolution of the bottom morphology of the lower Xingu. The results suggest a filling of the ria both by the Xingu River, forming a prominent headwater delta, and the Amazon River, where tidal variations transport sediments upstream in the Xingu River. On the other hand, large areas in the central part of the ria indicate muddy sedimentation. Elementar geochemistry allowed us to trace part of the history of sediments and source rocks, together with the analysis of immobile elements (Al, Ti, Zr, Hf, Th) and rare earth elements (REE) because they are poorly fractionated during weathering processes. and they are concentrated in the bottom sediments to the detriment of the dissolved fraction of the rivers. The deposits preserved in the lower Xingu River, despite draining cratonic regions in higher areas, confirm that the bottom material is derived from heterogeneous sources with predominantly intermediate igneous compositions and that they underwent important recycling during fluvial transport. The hydrodynamic modeling allowed to indicate the fluvial discharge as the most relevant forcing for the muddy deposition dynamics in the Xingu estuary. From a numerical model, it was possible to extrapolate the flow and transport dynamics beyond the open boundaries, that is, the central portion of the ria, elucidating the interaction mechanism between river and tidal discharge and the associated sedimentary dynamics. The determination of the amplitudes and phases of the tidal components, whether of purely astronomical origin or resulting from shallow waters, as well as the average level and the hourly discharge proved to be fundamental for the understanding of the governing processes.Item Acesso aberto (Open Access) Impacto do volume de sólidos sedimentáveis no escoamento hidráulico e no custo de manutenção de canal de drenagem(Universidade Federal do Pará, 2021-12-13) REBÊLO, Marcos Vinicius da Silva; PEREIRA, José Almir Rodrigues; http://lattes.cnpq.br/9918600634569244The Impact of sedimentable solids volume on hydraulic flow and drainage channel maintenance Cost. The study area was the Tamandaré drainage basin, located in the central region of the city of Belém/PA. The research was developed in three stages. Initially, the situation of the Tamandaré Channel was analyzed, investigating the main information related to the management of rainwater in the studied basin, obtaining topographic, hydrological and drainage system data. Then, the main factors and contributors to sediment accumulation in the channel were surveyed. Finally, in the Storm Water Management Model 5.0 software, a simulation was performed with the ideal operation of the drainage channel without the occurrence of solids and precipitation to serve as a parameter for further simulation with the occurrence of solids. The subsequent step simulated scenarios with sedimentation of solids in the macrodrainage structure, considering: a) rainfall, lasting 1.5 h, 3 h, 6 h and 12 h and b) 10%, 20% and 30% of the Channel obstructed by sediments, resulting in 15 hydrodynamic simulations. The last stage of the research presented the Hydrodynamic impacts, demonstrating that the capacity of the Tamandaré channel is sufficient to drain the precipitated volumes with 10% of its volume committed to solids. However, with 20% of the solids occupying the channel bed, flooding occurs in the scenarios of 1.5 h, 3 h, and 6 h of rainfall, only in the 12 h simulation there was no flooding because, with this storm scenario, the precipitation was more distributed, favoring channel flow. The scenario of 30% of the channel occupied with solids resulted in flooding in all precipitation scenarios, the highest flood magnitude occurred during rainfall of 1.5 h reaching 3.44 m, generating a water level of up to 1.07 m above ground on the roads close to the Tamandaré channel. The cost analysis showed that with the current spending scenario it would be possible to keep the Channel free of solids, as long as this cleaning took place on a daily basis in the indicated volumes equivalent to 2 tipper buckets 2 times a day, however, no cleaning in some days such as Sundays and holidays made the accumulation of waste a reality in the canal. Thus, it is necessary to complement the cleaning of the channel for the total removal of the sediments in this drainage channel in the densely occupied urban area of the municipality of Belém.