RESUMO O entendimento do escoamento de sedimentos é fundamental para a adequada gestão e uso dos recursos hídricos. A falta de planejamento de uso e ocupação do solo, marcado por ações antrópicas irracionais, influencia diretamente a dinâmica dos sedimentos nas bacias hidrográficas em todo o território nacional. Nesse sentido, o presente artigo teve como objetivos determinar as descargas de sedimentos, analisar fatores que podem influenciar o carreamento de sedimentos na bacia hidrográfica e construir as curvas-chave que representam a relação entre as descargas sólida e líquida no rio Jordão. O estudo foi realizado na Bacia Hidrográfica do Rio Jordão, estabelecendo-se quatro estações de amostragem, sendo realizadas nove campanhas de medições de vazões e coletas de água para análise de sedimentos suspensos em épocas secas e chuvosas no período de agosto de 2017 a julho de 2018. As concentrações e descargas de sedimentos apresentaram variações entre as estações e os períodos de amostragem. Na época chuvosa, os valores das descargas e concentrações foram superiores ao período de estiagem. A maior concentração média foi de 101,16 mg.L-1 na estação 3, e a maior descarga sólida total ocorreu na estação 4, com valor médio de 113,83 t.d-1. Além da precipitação, fatores como cobertura vegetal, uso do solo e declividade influenciam o carreamento dos sedimentos no rio Jordão. As curvas-chave de sedimentos em suspensão e totais, para cada estação e para os dados unidos de todas as estações, apresentaram boas correlações.

Hydrosedimentological studies are fundamental for the adequate management of water resources. The Jordão River, the research study area, has the potential to generate electricity to serve a region of the TriânguloMineiro and Alto Paranaíba. In this sense, the understanding of sediment transport resources is important, since it represents a fundamental contribution for ensuring adequate management of water resources in the region. This research study has the general objective of examining sediment transport in the Jordão River, with the aim of obtaining a preliminary understanding into the dynamics of solid particles in this water body. To this end, the determination of the key curves of Flow vs Sediment concentration, the characterization of the sediment granulometry and the hydraulic and geometric aspects of the studied stations, as well as the analysis of the factors that influence the dynamics of sediments in the river, will be carried out. For this purpose, four sampling stations were established, fourteen campaigns were carried out for flow measurements and water and sediment collections for the analysis of suspended and bed sediments in dry and rainy seasons from August 2017 to December 2018. A relationship between suspended sediment concentration and liquid discharge is found in the literature as Css = α·Qβ, at the four stations on the Jordan River during the measured period, with a value of 14.593 <α <26.904 and 0.6722 <β <0.9462, along with the graph representing all values Css = 22.944·Q0.6991. Noteworthy from the collections carried out is the relationship between rainy and dry seasons, where there is no increase verified in the filming of sediments with the increase in the flow of the river. Regarding the bed solids obtained through granulometric curves, there is a noted deposit of sediments with less granulometry in the dry season, mainly in seasons 3 and 4.

The understanding of the sediment flow is fundamental for the adequate management of the water resources. The lack of planning for land use and occupation marked by irrational anthropogenic actions directly influences the sediment transport in river basins throughout the national territory. The intensification of the transport of sediments causes several problems that interfere in the normal conditions of balance of the environment, damaging environmental, economic and social aspects. In this context, the research aims to study sediment transport in the Rio Jordão basin, which belongs to the Water Resources Planning and Management Unit-Alto Rio Paranaíba 1 (UPGRH-PN1), in order to understand the the flow of solid particles to contribute to studies related to silting reservoirs, planning and management of the region's water resources. For this purpose, four sampling stations were established, fourteen campaigns were carried out for flow measurements and collection of water and sediments for the analysis of suspended and bed sediments during dry and rainy seasons from August 2017 to December 2018. With this it was possible to estimate the solid discharge by different methods; characterize the sediment granulometry and the hydraulic and geometric aspects of the studied sections; build the key curves of liquid and solid flow; simulate sediment transport from the computational tool (HEC-RAS); and to analyze the factors that influence sediment transport in the river basin of the Jordan River. The results showed that sediment concentrations and discharges showed variations between the seasons and sampling periods. In the rainy season the values of discharges and concentrations were higher than in the dry season. In the rainy season the values of discharges and concentrations were higher than in the dry season. The sediment and total sediment key curves obtained for each season and for the united data of all seasons showed good correlations. The simulations indicated temporal and spatial trends of erosion and sediment deposition along the river.

Os problemas ambientais relacionados com as atividades antrópicas têm aumentado significativamente com o crescimento populacional e o uso irracional dos recursos ambientais. As atividades associadas às alterações no uso e ocupação da terra têm gerado degradação ambiental, comprometendo os recursos naturais. As técnicas de sensoriamento remoto e SIG são ferramentas poderosas para investigar e prever mudanças ambientais de um modo confiável, não invasivo, rápido e econômico com estratégias consideráveis de tomada de decisão. A avaliação temporal da vulnerabilidade ambiental de uma Bacia Hidrográfica é essencial para indicar as limitações e potencialidades do uso e ocupação do solo, contribuindo para o entendimento da dinâmica ambiental e uma possível tomada de decisão relacionada com a gestão dos recursos ambientais. No presente trabalho foi proposta a avaliação temporal da vulnerabilidade ambiental da Bacia do Uberabinha em Uberlândia – MG entre os anos de 2010 e 2017 a partir da análise multicritério com a utilização da AHP. No estudo foi observado a intensificação da vulnerabilidade ambiental ao longo dos anos. Portanto fica evidente a necessidade de ações efetivas na tentativa de interromper o processo de degradação e garantir a preservação do ambiente.

Ensuring quality food, and in sufficient quantities, is a global challenge. The use of fertilizers is of fundamental importance, since it promotes the increase of agricultural yield of poor productive soils. Brazil has enormous agricultural potential, but due to soil conditions, it needs large amounts of fertilizer. Despite the high demand, domestic production is not sufficient to meet consumption and needs to resort to imports. Regarding potassium fertilizers, the country currently imports about 90% of its total demand. Potash evaporitic deposits are the main sources of K, but besides having few deposits, Brazil has only one mine in operation: Taquari Vassouras/SE. Verdete, a silicate rock that has considerable potassium content, is an alternative source for obtaining the element. This work aims to analyze the efficiency of K recovery from Verdete through reaction with calcium hydroxide under hydrothermal conditions. The obtained solid products were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). K extraction was performed in the presence of citric acid and water, with subsequent analysis by flame photometry. The products were filtered, and the filtered and retained fractions were characterized aiming to determine the crystalline structures that compose them. The results showed that the reaction between Verdete and calcium hydroxide begins to occur effectively after 2 h, and that release of K + occurred mainly due to breakdown of K-feldspar lattice. The solid fraction of hydrothermal products is composed mainly of hibschite and tobermorite. In filtered products, the soluble phase consists mainly of calcium carbonate in calcite and aragonite forms. Finally, the results showed that citric acid promoted higher potassium extraction than water. This implies that, after the hydrothermal procedure, even if the element has already been extracted from the crystal lattice of K-feldspar, K + ions still interact with the remaining solid in an unknown way, but treatment with acid solution enables its final extraction into the liquid phase.