Análise do volume de sedimentos assoreados e da taxa de urbanização em bacias hidrográficas urbanas : estudo de caso Reservatório Mãe d’Água

The Mãe d`Água reservoir is the mouth of four streams, corresponding to an area of 352 ha and is located in the Vale Campus of the Federal University of Rio Grande do Sul. The study area is currently predominantly characterized by a residential occupation, with environmental liabilities coming from diffuse sources. The application of the methodology for computational modeling in the Mãe d'Água reservoir, inferring about the useful volume of the project in 1962, useful volume in 2014, and the silting volume was developed with the aid of the following software: AutoCAD 2018, AutoCAD Civil 3D 2018, and Google Earth which specialize in the field of geoprocessing and guidelines for the calculations that use as base the data regarding the survey and processing of field data. Two types of remote sensing products were used to evaluate the evolution of urbanization in the study area: aerial photographs and satellite images which were integrated in a geographic database. Through the results, it was possible to verify that the silting volume occupies approximately 44% of the useful volume of the reservoir, the urbanization rate has growth trends, and, 88.42% of the river basin was urbanized in 2014. Thus, it represents a spatial distribution and establishes correlations between sedimentation studies over the last five decades.A barragem Mãe d`Água é o exutório de quatro arroios, correspondendo a uma área de 352 ha e se situa no Campus do Vale da Universidade Federal do Rio Grande do Sul. No presente momento a área de estudo encontra-se predominantemente caracterizada por uma ocupação residencial, com passivos ambientais advindos de fontes difusas. Aplicação da metodologia para a modelagem computacional no reservatório Mãe D’Água inferindo sobre o volume útil de projeto em 1962, volume útil em 2014 e o volume de assoreamento, foi desenvolvida com o auxílio de softwares: AutoCad 2018, AutoCad Civil 3D 2018 e Google Earth, que são especializados no campo do geoprocessamento e diretrizes para os cálculos que utilizam como base os dados referentes ao levantamento e processamento dos dados de campo. Para a avaliação da evolução da urbanização na área de estudo foram utilizados dois tipos de produtos de sensoriamento remoto: fotografias aéreas e imagens de satélite, que foram integradas em um banco de dados geográficos. Através dos resultados, foi possível constatar que o volume do assoreamento ocupa aproximadamente 44 % do volume útil do reservatório e a taxa de urbanização com tendências de crescimento e para o ano de 2014 com 88,42 % da bacia urbanizada, configurando, portanto, uma distribuição espacial e estabelecendo correlações entre os estudos da sedimentação ao longo das últimas cinco décadas

Concentrations and enrichment of metals in sediment cores : geochemistry and correlations with geoaccumulation index

The Mãe d’Água dam was built in 1962 to supply the Federal University of Rio Grande do Sul’s water demanding. Thus, the paper aims to measure Nickel (Ni) and Zinc (Zn) concentrations in many depths of the dam’s bottom, sampling cores of sediments silted in it. The samplings were carried out in June, 2014, and it was sampled four sediment cores in pre-defined points of the dam. The methodology for extraction of sediment cores was ‘Piston Core’. Sediment particles smaller than 63 μm were separated and used for chemical analysis. EPA 3050 acid digestion methodology is used by the U.S. Environment Protection Agency and it was also used in this study. Analyses were carried out in duplicate and two USGS reference materials were used for quality control: SGR-1b and SCO-1. Zn and Ni concentrations were over than local background values and increasing concentrations of the deepest sendiments to the most recent layers as a result of urbanization activities. Geoaccumulation index was able to characterize decreasing of metal concentrations in depth.A barragem Mãe d'Água, foi construída em 1962, a fim de atender à demanda da Universidade Federal do Rio Grande do Sul. Assim, este trabalho tem como objetivo avaliar as concentrações de Zn e Ni em diferentes profundidades amostradas no núcleo de sedimentos produzidos nesta bacia hidrográfica. As coletas das amostras foram realizadas em junho de 2014, sendo amostrados quatro núcleos de sedimentos distribuídos no lago da barragem. Para a extração dos sedimentos de fundo foi utilizado um amostrador core Piston Core. Os sedimentos da fração menor que 63 μm foram destinados à análise química para verificação da presença e concentração dos elementos traço: Níquel (Ni) e Zinco (Zn). A metodologia de digestão ácida empregada é a EPA 3050, adotada pela U.S. Environment Protection Agency, sendo que as análises foram realizadas em duplicata e, para controle de qualidade, foram utilizados dois materiais de referência da USGS (U.S. Geological Survey): SGR-1b e SCO-1. Os resultados obtidos mostraram que as concentrações de Zn e Ni nas amostras apresentaram-se acima do valor de background local e com padrões de crescimento, conjuntamente, o índice geoacumulação evidencia a existência de enriquecimento dos sedimentos por estes elementos provavelmente devido às atividades urbanização locais

Análise do volume de sedimentos assoreados e da taxa de urbanização em bacias hidrográficas urbanas; estudo de caso Reservatório Mãe d’Água

The Mãe d`Água reservoir is the mouth of four streams, corresponding to an area of 352 ha and is located in the Vale Campus of the Federal University of Rio Grande do Sul. The study area is currently predominantly characterized by a residential occupation, with environmental liabilities coming from diffuse sources. The application of the methodology for computational modeling in the Mãe d'Água reservoir, inferring about the useful volume of the project in 1962, useful volume in 2014, and the silting volume was developed with the aid of the following software: AutoCAD 2018, AutoCAD Civil 3D 2018, and Google Earth which specialize in the field of geoprocessing and guidelines for the calculations that use as base the data regarding the survey and processing of field data. Two types of remote sensing products were used to evaluate the evolution of urbanization in the study area: aerial photographs and satellite images which were integrated in a geographic database. Through the results, it was possible to verify that the silting volume occupies approximately 44% of the useful volume of the reservoir, the urbanization rate has growth trends, and, 88.42% of the river basin was urbanized in 2014. Thus, it represents a spatial distribution and establishes correlations between sedimentation studies over the last five decades.A barragem Mãe d`Água é o exutório de quatro arroios, correspondendo a uma área de 352 ha e se situa no Campus do Vale da Universidade Federal do Rio Grande do Sul. No presente momento a área de estudo encontra-se predominantemente caracterizada por uma ocupação residencial, com passivos ambientais advindos de fontes difusas. Aplicação da metodologia para a modelagem computacional no reservatório Mãe D’Água inferindo sobre o volume útil de projeto em 1962, volume útil em 2014 e o volume de assoreamento, foi desenvolvida com o auxílio de softwares: AutoCad 2018, AutoCad Civil 3D 2018 e Google Earth, que são especializados no campo do geoprocessamento e diretrizes para os cálculos que utilizam como base os dados referentes ao levantamento e processamento dos dados de campo. Para a avaliação da evolução da urbanização na área de estudo foram utilizados dois tipos de produtos de sensoriamento remoto: fotografias aéreas e imagens de satélite, que foram integradas em um banco de dados geográficos.  Através dos resultados, foi possível constatar que o volume do assoreamento ocupa aproximadamente 44 % do volume útil do reservatório e a taxa de urbanização com tendências de crescimento e para o ano de 2014 com 88,42 % da bacia urbanizada, configurando, portanto, uma distribuição espacial e estabelecendo correlações entre os estudos da sedimentação ao longo das últimas cinco décadas

EVOLUTION OF ENRICHMENT OF SEDIMENTS BY TRACE METALS (Ni AND Zn) IN A DAM OF URBANIZED WATERSHED

Sediments represent and provide a response to the condition of the environmental system in which they are found, acting as a point for deposition of contaminants. Upon developing studies of sediment columns, it is possible to obtain the historic records of substances arising from activities developed in the watershed over recent years. In this context, the present study investigates the enrichment of the sediments produced in an urban residential catchment area by the trace metals zinc and nickel. The sediment fraction smaller than 63 μm was analyzed in three sediment cores from the dam. Chemical analyses verified the concentration of trace metals by the acid digestion method EPA 3050. In carrying out analyses of the evolution of urban settlement in the watershed, the values corresponding to natural and human-impacted areas were determined through the use of different remote sensing products: aerial photographs (from 1972 and 1991) and high resolution satellite images (from 2003 and 2008). Natural areas were reduced in four decades, and population density in already human-impacted areas proved to be an important factor for understanding the urbanization process of the area. All sediment samples analyzed showed Zn and Ni concentrations above the local background value and with a pattern of growt

Urban Street Pollutants

The sediments carried by runoff water are an important part of this process because their presence in the bodies of water not only cause sedimentation problems but, mainly, they contaminate the water due to the presence of the pollutants found associated with sediments. The urban subwatershed under study is located in the metropolitan region of Porto Alegre city, Brazil. This paper aims to present the relation between pollutants on the street sediments and in suspended sediment sampled in the river. The collections of suspended sediment samples begun in the end of 2003 and finished in the end of 2006. Collections of urban dust samples (47 samples per km²) were taken in the main diffuse sources of the urban environment, represented by paved and non-paved streets, beyond the area with remaining vegetation, in some points of the bed river and in its margins. During these analyses, it was studied 29 samples of fluvial suspended sediments. The elements selected for this study are some of the most frequently found in high concentrations in urban areas (Zn, Pb and Cu). The results suggest it is occurring a high enrichment of the local sediment with these metals. The concentrations of these elements vary temporally during storms due the input of road runoff containing elevated concentrations of elements associated with vehicular traffic and other anthropogenic activities. In general, they have their most concentrations on the streets but they are carried to the channel during the storms.The sediments carried by runoff water are an important part of this process because their presence in the bodies of water not only cause sedimentation problems but, mainly, they contaminate the water due to the presence of the pollutants found associated with sediments. The urban subwatershed under study is located in the metropolitan region of Porto Alegre city, Brazil. This paper aims to present the relation between pollutants on the street sediments and in suspended sediment sampled in the river. The collections of suspended sediment samples begun in the end of 2003 and finished in the end of 2006. Collections of urban dust samples (47 samples per km²) were taken in the main diffuse sources of the urban environment, represented by paved and non-paved streets, beyond the area with remaining vegetation, in some points of the bed river and in its margins. During these analyses, it was studied 29 samples of fluvial suspended sediments. The elements selected for this study are some of the most frequently found in high concentrations in urban areas (Zn, Pb and Cu). The results suggest it is occurring a high enrichment of the local sediment with these metals. The concentrations of these elements vary temporally during storms due the input of road runoff containing elevated concentrations of elements associated with vehicular traffic and other anthropogenic activities. In general, they have their most concentrations on the streets but they are carried to the channel during the storms

Aumento da desertificação na Patagônia Argentina : interferências antrópicas

The United Nations [UN] declared 2015 as the International Year of Soils and hopes that this initiative will serve to mobilize society for the importance of soil as a key part of the environment and the dangers surrounding their degradation in the world. The work will address the desertification process in Argentinian Patagonia, in order to intensify this process over time by human occupation. For this analysis, we used historical and current references, addressing an evolutionary outlook, illustrated with maps and quantitative data. The methodology focused on analysis of the first records of the phenomenon, identification and perception of it as a problem that has natural characteristics, but this is powered by anthropic processes with a soil occupation which is different from what the environment would bear with exploration of possibilities that did not consider the native vegetation and the natural system. The results identified point to a sheep and cattle herd growth in parallel with the evolution of desertification. It is possible to mention the characters responsible for such changes, which result in an environmental, social and economic imbalance, and alternatives for the process to be attenuated or mitigated are suggested.A Organização das Nações Unidas [ONU] decretou 2015 como o Ano Internacional dos Solos e espera que a iniciativa sirva para mobilizar a sociedade para a importância dos solos como parte fundamental do meio ambiente e os perigos que envolvem a degradação deles em todo o mundo. O trabalho abordará o processo de desertificação na Patagônia Argentina, observando-se a intensificação desse processo ao longo do tempo pela ocupação humana. Para esta análise, foram utilizadas referências bibliográficas históricas e atuais, que abordam um panorama evolutivo, ilustrado com mapas e dados quantitativos. A metodologia concentrou-se na análise dos primeiros registros do fenômeno, na identificação e na percepção do mesmo como um problema que apresenta características naturais, porém está sendo potencializado por meio de processos antrópicos com uma ocupação do solo divergente da que o meio ambiente suportaria, com possibilidades de exploração que não consideraram a vegetação nativa e o sistema natural. Os resultados identificados apontam para um crescimento do rebanho de ovinos e bovinos em paralelo com a evolução do processo de desertificação. Podem-se apontar os personagens responsáveis pelas modificações, que resultam em um desequilíbrio ambiental, social e econômico, e sugerem-se alternativas para que o processo seja atenuado ou mitigado