Engenharia Ambiental

URI Permanente desta comunidade

http://repositorio.ufes.br/handle/10/17610

Programa de Pós-Graduação em Engenharia Ambiental

Centro: CT
Telefone: (27) 3335 2324 R*9510
URL do programa: http://www.ambiental.ufes.br/pos-graduacao/PPGEA

Navegar

Agora exibindo 1 - 20 de 245

Análise da influência da descarga do rio Santa Maria da Vitória sobre a propagação da onda de maré e da hidrodinâmica tridimensional da Baía de Vitória
(Universidade Federal do Espírito Santo, 2013-12-16) Nascimento, Thiago Freitas do; Aquije Chacaltana, Julio Tomás; Daniel, Rigo; Harari, Joseph
The tidal wave is damped in estuarine regions and progressively distorted by frictional forces in the bottom, by river discharge, by narrowing/abrupt enlargements in the channels and by the presence of vegetation areas. In this paper the study is conducted to understand the induced tidal wave along the Porto de Vitória and check the river discharge influence of the Rio Santa Maria da Vitória in hydrodynamics. The hydrodynamic model used in this work is MOHID in three-dimensional barotropic mode and deployed throughout the estuarine system of the Ilha de Vitória. And the simulation period corresponds to the year 2009. As the tidal boundary condition, the model was forced by a set of harmonics, which were extracted from a long series of tidal data by Pacmaré program. And the data of river discharge of Santa Maria da Vitoria were obtained from the National Water Agency (ANA) website. As a boundary condition in the bottom was used length values equivalent roughness, which were extracted from the maps of study by Paiva (2008). While the mangrove region the value of 3 meters was used, as the work of Maciel (2004) and Nascimento et al. (2011). A rectangular mesh horizontally at regular intervals of approximately 56x56 meters was used, while for the vertical discretization a mesh sigma type was used with 10 layers. The results founded for the tide waves in the Baía de Vitória was observed that the tidal wave to propagate upstream of the estuary, the M2 and S2 components has a different behavior, while the first is amplified the second is reduced. Moreover, the region of Baía de Vitória is where the shallow water harmonic suffers more influence. During periods of high river discharge the tidal wave tends to be blocked, resulting in a number of harmonics and amplitude lower compared with periods of low river discharge, corroborating the results of Goring (1984), Godin (1985); Nicoliti (2007); Nicoliti et al. (2009). It was ascertained that at least 11 harmonic constituents are common to the period of low river discharge, are absent in the period of high river discharge analyzed. For the period low river discharge, we realized the presence of multiple vortices when analyzing residual streams and these vortices no was noted in the period of high river discharge. Thus, it was found that during periods of high river discharge the water quality of the estuarine system of Ilha de Vitória may suffer a substantial improvement. However, when we analyzed the hydrodynamics of the Baía de Vitória, it was found that there is a phase difference between the northern and southern parts, and the highest velocities are found in the southern part of the bay, which is aligned with the work done by Garção (2007) and Rigo (2004). However, during high river discharge events the northern part of the bay runs like a river, flowing in one direction throughout the tidal cycle, and it is in this region where the highest velocities are found. Finally, a reversal of dominance was observed in the region, in the periods of spring tide the estuary is ebb dominant and in the periods of quadrature the estuary is flood dominant, these result also was found by Rigo (2004). Furthermore, it was noted that during low tide the highest velocities are found in the subsurface in central region of Baía da Vitória.
Análise da influência da especificação do uso e ocupação do solo e do uso da técnica de assimilação de dados meteorológicos na performance do modelo WRF
(Universidade Federal do Espírito Santo, 2017-04-06) Aylas, Georgynio Yossimar Rosales; Albuquerque, Taciana Toledo de Almeida; Reis Junior, Neyval Costa; Santos, Jane Meri; Moreira, Davidson Martins; Pimentel, Luiz Claudio Gomes
Air quality models require accurate meteorological elds and geographic data to make the correctly modeling of chemical transport. For this purpose, the Metropolitan Region of Greater Victoria (RMGV) uses the numerical mesoscale model WRF. The physical and biological property of the land surface has been progressively a ected as a consequence of the change in land use. This is mainly due to urbanization and farming and forest practices. However, the problem about the use of parameters such as soil coverage provided by the USGS is that they are available with ultimate update date in 1993. In addition, there is the high computational cost about the assimilating of real data (observational meteorological data) to obtain more improve on the forecasts. For this purpose this study has the main goal evaluate the input datas regarding to land use and cover, together whit speci cation the meteorological assimilation data (pontual observations) to evaluate the performance of the WRF model for the Região Metropolitana da Grande Vitória (RMGV). As part of the work of generating accurate spatial data, satellite image analysis was performed. These provide excellent data quality, with enough information to generate the desired geographic data. Therefore, we have worked speci cally for a small 120km x 120km area that covers the RMGV whole and is centered at the Airport Station. On the other hand, to make the data treatment with the objective of implementing the new geographic database for the RMGV, several steps were followed. These was grouped on the preprocessing of images for the land use and cover with the 24 categories of land use suggested by the USGS and the equivalent to the brazilian sistem for the RMGV area. However, for soil granulometry and texture it had no greater problem than accurate the existing information, as well as to Topography. As well as, for the four-dimensional data assimilation (FDDA), the Newtonian relaxation or nudging (continuous data assimilation method that adjusts the model's dynamic variables gradually for observations by adding one or more prognostic equations) were generated les containing the reports of the surface meteorological data of the Aeroporto station. As a consequence, the modeling performance of the direction and speed of the wind and temperature. In consequence, the modeling performance of the speed and direction of the wind and temperature, using to modeling with updated geographical database has a slight improve compared with using USGS data source. Although, not every month they hit the ags for the suggested indicators for all seasons. However, to evaluate the modeling performance of wind direction and speed and temperature for all seasons, making use of the updated geographic data with the in uence of nudging a ecting the domain d01 improvement in every month. Thus, when the in uence of nudging for domain d02 is used, it improves modeling even more than when was used together domains d01 and d02 is in uenced.
Análise da influência da precipitação pluviométrica e do uso do solo sobre a qualidade da água em microbacias hidrográficas no nordeste paraense: Amazônia Oriental
(Universidade Federal do Espírito Santo, 2011-08-08) Veronez, Brunella Pianna; Mendonça, Antônio Sérgio Ferreira; Rigo, Daniel; Oliveira, Francisco de Assis
When forest is removed, giving way to agricultural production systems, pastures and urbanization, not just the landscape is drastically changed but watercourses quality is modified. The multiple uses of water and human activities in a watershed may cause significant changes in water quality. This study aims to acquire better knowledge about the influence of rainfall and soil use on water quality of watersheds located in the Amazon biome. The field survey was developed in Praquiquara watershed, Castanhal city, Pará state, Brazil. GIS was used for the delineation and mapping of land use in Praquiquara watershed and 8 (eight) sub-basins corresponding to the water quality monitoring stations. Water quality monitoring occurred in 4 (four) field surveys, distributed during rainy and dry seasons. It was concluded that the use and occupation of land in the watershed have a great influence on several water quality parameters. Parameters showing the largest changes were: turbidity, total suspended solids, total solids, DO, BOD, Iron and thermotolerant coliforms. The parameters that showed violations of legal standards for water quality were: pH, Dissolved Oxygen, BOD and thermotolerant coliforms. The results of water monitoring also showed great influence of rainfall on water quality parameters. BOD, nitrate, and iron are among the parameters that have presented concentration reduction during the rainy season. Total Suspended Solids, Dissolved Oxygen, Ammonia Nitrogen, Ammonia and nitrite are among the parameters for which concentration increased during the rainy season
Análise da influência do escoamento no interior de uma câmara de fluxo dinâmica na taxa de emissão de sulfeto de hidrogênio
(Universidade Federal do Espírito Santo, 2016-03-30) Andreão, Willian Lemker; Santos, Jane Meri; Reis Junior, Neyval Costa; Vieira, Rodrigo Silveira
The wastewater treatment process lead to formation of odorous compounds, as hydrogen sulphide (H2S), which can cause nuisance and disturbance to health of nearby residents. The dynamic flux chamber (or flux hood) is widely used to estimate the emission of odorous gases from quiescent liquid surfaces, presented in wastewater treatment plants. The geometry of the flux hood must promote a complete mixing of the volatilized gas within the hood to the emission measured be independent of the point sampling. An auxiliary device, as a small fan, it is commonly used for this purpose. This study investigated the influence of the flow inside the chamber on the transport of H2S and its emission rate. Mathematical modeling of these phenomena was performed through the numerical solution of the transport equations considering the turbulent flow using ANSYS-CFX 14.5 code. The results show that a flux hood with eight air inlets promote a concentration distribution more homogeneous, although the friction velocity at interface (0.007 m s-1 ) is not sufficient to promote an appropriate sweeping on interface, where it is found high values of concentration. In standard configuration (US EPA model), with four inlets, clean air jet can reaches the sampling probe, affecting in the concentration values measured. If micro fans are used, turbulence created within the hood and friction velocity are significantly higher. Concentration quickly reaches stationary state within the hood (1 to 2 min) and the final emission rate is on average 25.3% higher with the use of micro fans. If the purpose of using the flux hood is to represent environmental conditions that would be found in the field, it is recommended to use micro fans.
Análise da influência do Rio Santa Maria da Vitória na Baía de Vitória, através da modelagem computacional: uma contribuição ao processo de enquadramento
(Universidade Federal do Espírito Santo, 2007-04-01) Saldanha, Jeanne Cristine Schmidt; Rigo, Daniel; Azevedo, José Paulo; Mendonça, Antônio Sérgio Ferreira
Coasts and firths are environments in which human impacts have caused a variety of changes. Among the main impact is the increasing use of water resources, which has caused several quality and quantity of water conflicts. In order for the control and monitoring actions to be effectively adopted, aiming at lessening the damage caused by these practices, one should understand the movement pattern of the relevant bodies of water as well as their correlation with the water quality. This is the purpose of this paper. To do so, a computer model of the region comprising the final section of the Santa Maria da Vitória River and Vitória bay was implemented. It was named SisBAHIA. After the model was calibration and verification, the hydrodynamic characteristics of the region were associated with aspects related to water quality, by performing component transport simulations. These simulations allowed the analyses of the influence of river output on the saline intrusion behavior; correlation of river and tide conditions with concentrations in the Vitória bay firth area, considering a conservative component; and evaluation of the amount of water in the region considering a non-conservative component, by using several river and tide output scenarios. It is intended that the obtained results contribute to the process of classification of the Vitória Bay. Results should also provide data to allow access to information, in order to help make decisions and manage the studied region coast. This aims at improving the quality of life of the people using the bay water
Análise das deformações viscosas e da segregação de fases em floculadores tubulares helicoidais e suas relações com a razão de curvatura
(Universidade Federal do Espírito Santo, 2015-12-02) Sartori, Maurício; Teixeira, Edmilson Costa; Pires, Eduardo Cleto; Rauen, William Bonino; Aquije Chacaltana, Julio Tomás; Rigo, Daniel
Helical tubular flocculators (FTHs) when compared with the currently employed hydraulic flocculato s in water and wastewater treatment plants have demonstrated high efficiency in the floc formation with low hydraulic retention time (Tdh) and high power dissipation levels, challenging the current flocculation paradigm (high Tdh and low energy dissipation levels). However, the mechanisms that enable these flocculators operating satisfactorily in these operational conditions have not yet been elucidated. It is known that the fluid viscous deformations present a great influence on the collision opportunity and, consequently, on the flocculation. Another factor that also has relevance in the flocculation is the particles’ concentration which, in the current models, it is assumed uniform throughout the reactor. In this context, aiming at enhance the understanding of the flocculation in those flocculators, this work presents an evaluation of the influence of the FTHs’ curvature ratio (d/D, where d is the tube diameter and D is the coil diameter) on the fluid elements strain rate, which has been assumed to be the main collision mechanism between particles. It is also shown that d/D influences the phase segregation, a characteristic of two-phase flows in curved pipes. For this purpose, we evaluated 5 FTHs configurations with curvature ratio of 0.0091, 0.0182, 0.0364, 0.0729 and 0.1458, with the support of computational fluid dynamic simulations (monophasic and biphasic), with and without considering the gravitational field, by adopting horizontal and vertical coil axes, respectively. The results demonstrate the importance of taking into account the linear strains, neglected in some collision models, besides the direct relationship of the curvature ratio with both angular and linear strains, and, consequently, with the shear strain rate. Regarding the phases segregation, there was an inverse relationship with the curvature ratio. However, this segregation is influenced by the reactor's position relative to the gravitational field. In horizontal coil axis reactors, at each turn, there is a cycle of segregation and mixing. In vertical axis FTHs, there is a significant increase of particles’ concentration in the reactor region close to the inner wall, due to the combined effect of the secondary flow drag and gravitational attraction.
Análise de componentes principais e a modelagem linear generalizada: uma associação entre o número de atendimentos hospitalares por causas respiratórias e a qualidade do ar, na Região da Grande Vitória, ES
(Universidade Federal do Espírito Santo, 2013-04-30) Souza, Juliana Bottoni de; Santos, Jane Meri; Reisen, Valdério Anselmo; Leon, Antonio Carlos Monteiro Ponce de; Reis Júnior, Neyval Costa
This dissertation uses two statisticals tools, Principal Component Analisys (ACP) and Generalized Additive Model (GAM), jointly, to estimate the effect of the association between atmospheric exposure of PM10, SO2, NO2, O3 and CO and the number of admissions due respiratory diseases in children less than 6 years in the Regi˜ao da Grande Vit´oria, Brazil.Usually the atmospheric pollutants are considered the explanatory covariables in MAG, but since they have an autocorrelation structure, they must be used with caution. The PCA technique provides a new set of orthogonal variables, these variables are linear combinations of environmental variables.Therefore, We use this approach in MAG, hereafter denoted by GAM-PCA. However, the principal components obtained through the matrix of variance / covariance applied to processes indexed by time also exhibit the properties of temporal correlation. A countermeasure to attenuate the temporal correlation of the components is use the filtering method to transform the data in an atmospheric white noise process. The residual matrix is used to obtain these components and applied to the model MAG - method here called VAR-GAM-PCA. The empirical results show that this model removes the autocorrelations of the main components and indicates significant estimates of relative risk (RR) for each pollutant. The results confirm the hypotheses established, the main components have selected correlation and the autocorrelation lags. To adjust the GAM-PCA model, an ARMA(p,q) model was used in the residual matrix since that structure carried autocorrelation from the original data. The VAR model-MAG-ACP, besides producing more significant in RR estimates, generated best fit residuals. Compared to the usual modeling MAG, the two strands proposals presented better results, both in estimating the RR and the quality of the fit.
Análise de componentes principais em séries temporais multivariadas com heteroscedasticidade condicional e outliers : uma aplicação para a poluição do ar, na Região da Grande Vitória, Espírito Santo, Brasil
(Universidade Federal do Espírito Santo, 2016-04-01) Monte, Edson Zambon; Reisen, Valdério Anselmo; Bondon, Pascal; Ispány, Márton; Munaro, Celso José; Albuquerque, Taciana Toledo de Almeida; Reis Junior, Neyval Costa
Issues relating to air quality have become increasingly important, since many health problems come from air pollution. In addition, air pollution contributes to the degradation of the environment, contributing to the greenhouse effect. Thus, several studies adopting technical statistics have been conducted in order to contribute in the making of public and private actors with regard to combating pollution, prevention of high concentrations and formulation of laws for this purpose. The classical principal component analysis (PCA) is a statistical methodologies adopted. The PCA is used for dimensional reduction, cluster analysis, regression analysis, among others. However, among the studies that have adopted the classical PCA, a common feature is to neglect the conditional heteroscedasticity and/or the presence of additive outliers, which may lead to spurious results (misleading), since the estimated autocovariance matrix may be biased (estimated incorrectly). It is possible to note that the time series related to air pollution tend to present conditional heteroscedasticity and additive outliers. Then, the first paper of this thesis proposed to apply a multivariate filter VARFIMA-GARCH to the original data and use the classical PCA on residuals of the VARFIMA-GARCH model. Besides the volatility, this model was used to filter the temporal correlation and the long memory behavior. The application of the PCA on the residuals of the VARFIMA-GARCH model was more consistent with the environmental characteristics of the Greater Victoria Region (GVR), Esp´ırito Santo, Brazil, than the application using the original data The second paper, that is the core of this thesis, the technique of principal volatility components (PVC), proposed by Hu e Tsay (2014), was extended for a robust approach (RPVC), in order to capture the volatility present in the multivariate time processes, but considering the effects of additive outliers on conditional covariance, since these outliers may mask (“hide”) the conditional heteroscedasticity or even produce spurious volatility. The proposed RPVC improved the predictions of PM10 exceedance days in the Laranjeiras station, in the GVR.
Análise de componentes principais robusta em dados de poluição do ar: aplicação à otimização de uma rede de monitoramento
(Universidade Federal do Espírito Santo, 2014-10-30) Cotta, Higor Henrique Aranda; Reisen, Valdério Anselmo; Reis Junior, Neyval Costa; Ispany, Marton
Studies of data from air pollution originating from a network of air monitoring involve a large number of variables and observations. From the standpoint of statistical techniques, it is possible to analyze separately each variable of interest. However, this type of analysis can not contemplate the relationship dynamics between these variables. Because of this, it is necessary to use statistical techniques to handle, measure and analyze these data generated jointly. This branch of statistics known as Multivariate Statistics. One important multivariate technique in the area of air pollution is the Principal Component Analysis (PCA), which builds linear combinations of variables to explain the variance-covariance structure of the original data. Air pollution in the Principal Component Analysis is used for: creating indexes of air quality, identi cation of pollution sources, management of air quality monitoring network, preprocessor variables for generalized additive models, besides other applications. In this work PCA is used to study the management and scaling of the Network for Monitoring Air Quality in the Greater Vitoria Region. This work deals with the use of Principal Component Analysis (PCA) in time series with additive outliers. The PCA is one of the most important multivariate techniques which are linear combinations constructed to explain the variance-covariance structure of the original data. Although PCA assumes that the data are serially independent, this assumption is not found in practice situation in time series, e.g. Air Pollution data. PCs calculated from time series observations maintains their orthogonality property, but the components are found to be auto and cross-correlated, which depends on the correlation structure of the original series. These properties and their impact in the use of PCA are one of main objective of this work. Another contribution is related to the study of PCA time series under the presence of additive outliers by proposing a Robust PCA (RPCA) method. It is well known that additive outliers in time series destroys the correlation structure of the data. Since the PCs are computed by using the covariance matrix, the outliers also a ect the properties of PCs. Therefore the Robust PCA should be used in this context. The Robust PCA method proposed here is justi ed empirical and theoretically, and a real data set based on Air Pollution time serie is used to show the usefulness of the Robust PCA method in a real application.
Análise de desempenho do satélite TRMM na estimativa de precipitação sobre a região hidrográfica do rio Itapemirim
(Universidade Federal do Espírito Santo, 2017-12-20) Almeida, Karinnie Nascimento de; Reis, José Antônio Tosta dos; Mendonça, Antônio Sérgio Ferreira; Facco, Alexandro Gomes
There are several obstacles in conducting high quality hydrological studies. There is a low density of pluviometric stations, faults in historical series, difficulties without access to the site, there are no conditions to install the monitoring of availability and unavailability of the operator. These factors hamper analysis of precipitation regimes, hampering their study and maintenance of hydrological modeling in several places around the world. In this context, the use of remote sensing precipitation estimates represents an alternative for the appropriation of precipitation, especially in river basins that have low densities of rain gauges or pluviographs equiment. The present work evaluates the precipitation to annual totals, monthly totals and long term averages in the Itapemirim river basin, as well as to evaluate the occurrence of rainfall in satellite pixels and rainfall stations closest to the pixel, from The satellite was developed by a partnership between the National Aeronautics and Space Administration (NASA) and the Japanese Aerospace Exploration Agency (JAXA). Historical series corresponding to 14 rain gauges stations arranged throughout the area of the studied basin were studied. In addition, data from the TRMM satellite were analyzed for a spatial mesh of 25 km for the same study area, considering the period between the years 1998 and 2015. Two statistical analyzes were carried out, following the recommendations of the International Precipitation Working Group (IPWG), statistics of quantitative analysis and analysis of occurrence. he quantitative analysis represents the amount of rain precipitated over the area of extension, which indicated that the use of the data from the TRMM satellite presented as an efficient alternative for the appropriation of precipitated annual and monthly totals, in addition to the long term averages precipitation for the study area. On the other hand, the analysis of occurrence, pixel to pixel analysis, that studies the occurrence of a rainy event in the station and in the pixel, indicated that the satellite presented significant values, being that the TRMM satellite has capacity in about 50% of the cases to indicate correctly a rainy day, or drought day and total efficiency of over 70%.
Análise de estratégias de resposta a derramamento de óleo pesado no litoral do Espírito Santo utilizando modelagem computacional
(Universidade Federal do Espírito Santo, 2006-10-31) Ferreira, José Paulo; Martins, Renato Parkinson; Rigo, Daniel; Aquije Chacaltana, Júlio Tomás; Lima, José Antônio Moreira
The response to heavy oil spill in Brazil needs to be deeply discussed; in order to consider certain particularities not considered by the legislation. The sizing of the structure to be used does not take into account the oil characteristics, like density or viscosity, as well as, it treats the same way any volume of discharge bigger than 200m3, considering it simply as ‘great discharge’. The main objective of this study is to discuss the use of containment recovery and artificial dispersion, as response strategies to offshore heavy oil spills, besides the expected contribution of each response scenario as a function of the required mobilization effort. An oil spill computational model (OILMAP) is used to simulate a critical accidental heavy oil spill scenario in the south coast of Espirito Santo, the no-response scenario, which results in a big volume of oil reaching the, under a severe environmental conditions and in the case of a free slick. After that, the structure and the response times foreseen in the legislation for the containment and recovery of oil are tested, as the reference scenario. Besides a set of ten alternative response scenarios, with different response times and response structure, a series of containment and recovery strategies together with combined dispersion (mechanical and chemical) and also a response scenario exclusively composed by combined dispersion of the oil hypothetically spilled are simulated. The results obtained point toward a limitation of the response strategies in the case of a large spill under critical environmental conditions, once this work reveals that in optimum response scenario, a significant amount (~25%) of the volume initially spilled (15.000m3 ) continues reaching a large shoreline extent (~50km), in a relatively short period of time (~05days)
Análise de localização de emissários de efluentes com uso de modelagem de qualidade de água e otimização: estudo de caso
(Universidade Federal do Espírito Santo, 2018-09-24) Santos, Alinie Rossi dos; Mendonça, Antônio Sérgio Ferreira; Reis, José Antônio Tosta dos; Andrade, Larice Nogueira
The present study addresses the choice of more suitable sites for effluent discharge in river basin watercourses. This study aims to analyze the influence of effluent emissaries location on the water resources quality, considering violations of standards, and efficiencies required for treatment systems within a river basin. Pardo river basin, in Espirito Santo, was chosen as the study area, parameters considered were Dissolved Oxygen and Biochemical Oxygen Demand. Among the study tools, it was used a water quality model, implemented in Matlab, which reproduces mathematical formulations and conceptual and computational structures of QUALUFMG model, and the Genetic Algorithm, as optimization technique. In optimization method application, two objective functions were considered, minimizing the sum of efficiencies and minimizing inequity among treatment systems. For the location analysis, a new effluent emissary, with two possible discharge flows, had its location changed along the main river. Effluent location influence analysis was carried out by verifying the variability: sums and the number of stretches presenting violations to environmental standards, efficiencies required to treat the new effluent and the set of effluents existing in the basin, considering different positions to the new effluent discharge point. Results confirm the great importance of effluent discharge sites' adequate location for compliance with water quality standards for receiving watercourses and required treatment efficiencies. Simulations and optimizations such as those performed in the present study may help in choosing points at which effluents discharge have lower impacts on the quality of receiving water bodies and require smaller treatment efficiencies in river basins.
Análise de metodologias de estimativas de vazão de diluição para subsídio a processos de análise de outorgas de lançamento de efluentes
(Universidade Federal do Espírito Santo, 2011-08-19) Zandonadi, Lorenza Uliana; Mendonça, Antônio Sérgio Ferreira; Kishi, Regina Tiemy; Pinto, José Antonio da Rocha
Grants for sewage discharge is an important tool to control water pollution. However, in Brazil, there is no legal provision that define criteria to analyze this type of grant. Methods for estimating sewage dilution are proposed in the literature, and these support the grant process. The aim of this study is compare some of these proposed methods, considering different aspects of the watercourses. Simulations seven scenarios were performed, including the presence of other releases and abstractions of water, upstream and downstream the river, and change of framework classes. Furthermore, sensitivity analysis was performed, considering different conditions of flow incremental, natural concentrations of BOD of the river, values of the deoxygenation coefficients (K1) and sedimentation coefficients (K3). The applied methodologies were proposed by Cardoso da Silva & Monteiro (2004), Hora (2001), Nahon (2006), Roques (2006), Kelman (1997) and the Mass Balance Equation method, modified by MMA (2000). Results showed that depending of the different variables considered in equations and the values adopted the proposed methodologies can result in very different values. These results emphasize the great importance of the use of long-term monitoring techniques to more realistic analysis of grants.
Análise de metodologias para o cálculo da descarga de fundo, aplicada ao Rio Doce, ES
(Universidade Federal do Espírito Santo, 2012-08-17) Almeida, Livia Meneghel de; Rigo, Daniel; Teixeira, Edmilson Costa; Mauad, Frederico Fábio
Knowledge of bedload transport is of primary importance in a number of aspects in watershed management, including fluvial geomorphology and ecology, stability of engineered structures and navigation condition. Despite the fundamental importance of bedload measurement, the amount of variables involved in the bedload transport mechanics, as well the complexity of the interactions among the physical processes, makes it difficult to establish a fully satisfactory criteria to determine the solid transport, thus there is not an accepted universal method. With recent advances, new methods have been proposed for measuring the bedload transport. Therewith, the aim of this study was to evaluate the suitability of methodologies for bedload measurement on a reach of the Doce River, ES. For this were used traditional direct sampling method, with Helley Smith’s sampler; formulas proposed by Einstein & Brown (1950), Engelund & Hansen (1967), Ackers & White (1973), Yang (1973) e Van Rijn (1984); bedform movement methods, considering velocity of bedform displacement and the difference between bed surfaces; and bedload velocity using an ADCP. Results indicated an unstable flow, with a bed composed primarily of fine and medium-sized sand, and bedforms in transition. Bedload values obtained by different methods showed variation of different orders of magnitude, and the highest estimates were provided by the equation of Yang (1973). The application of the bedform movement methods has been complicated by the bed condition at the site. However, the bedload measured from the velocity of bedform displacement has been quite consistent with the hydraulic conditions. The equations of Engelund & Hansen (1967) and Van Rijn (1984), and the bedload velocity method showed excellent performance, and the latter being a very promising alternative for the measurement of the bedload. To confirm the suitability of these methods in the Doce river (ES) is suggested to be carried out more measurements, in a uniform stretch, primarily using the bedload velocity and the bedform displacement methods.
Análise de ondaletas aplicadas a sinais de turbulência na camada limite superficial
(Universidade Federal do Espírito Santo, 2008-08-21) Depizzol, Daniela Bertolini; Santos, Jane Meri; Reisen, Valdério Anselmo; Reis Jínior, Neyval Costa; Aquije Chacaltana, Julio Tomás; Bolzan, Maurício José Alves
abstract
Análise de sensibilidade de parâmetros do modelo hidrológico SWAT em função de diferentes características de bacias hidrográficas
(Universidade Federal do Espírito Santo, 2017-10-09) Teixeira, Laíza Fernanda Curti; Mendonça, Antonio Sérgio Ferreira; Rigo, Daniel; Cecílio, Roberto Avelino
Evaluation of mathematical models components behavior can be performed through sensitivity analysis, uncertainties and calibration techniques. In the study, it was sought to use these resources specifically for the hydrological Soil and Water Assessment Tool (SWAT) model, with the purpose of evaluating the application conditions to simulate flow in a watershed in Espírito Santo State, in Brazil and, later, simulate alternative land use and occupation scenarios in the basin. In the global sensitivity analysis, the most sensitive parameters were those related to surface and base flow. The SWAT showed, after parameters calibration, to be effective in the representation of the flow variable. The Nash and Sutcliffe (NSE) coefficient calculated for the monthly simulation was 0,72 and the bias percentage (PBIAS) 9,40, both considered satisfactory, according to the literature. However, for daily flow modeling the NSE index was very low, 0,21. It was observed that the highest values present in the daily data series strongly affected the NSE coefficient values. After calibration, three distinct scenarios were considered for the sub-basin: native forest, eucalyptus and pasture. The manual sensitivity analysis for the scenarios showed that there were no significant differences for most parameters. However, for the number curve (CN2) value eucalyptus and pasture scenarios were influenced in greater magnitude than native forest. A correlation between parameters of different movements processes was observed. In the evaluation of modeled output variables, for different scenarios, large differences were not observed for monthly averages. For the daily simulations, the particularities between the scenarios were better observed, mainly for greater precipitations events. The native forest showed higher flow rates for drought times, due to the higher base flows, while the pasture scenario returned superficial flow superior to the corresponding to other situations.
Análise de sensibilidade de parâmetros e de desempenho do modelo Soil and Water Assessment Tools (SWAT) na estimativa de vazões médias em bacias hidrográficas
(Universidade Federal do Espírito Santo, 2017-04-19) Moreira, Luana Lavagnoli; Rigo, Daniel; Mendonça, Antonio Sergio Ferreira; Cecílio, Roberto Avelino
Flows modelling is presents by uncertainties related to climatological input data and watershed physiographic characteristics. In order to get representative flows simulated from the study area it is necessary adjust these flows to observed data. A satisfactory calibration depends on some factors that interfere in this process. Thus, the efficacy of the calibration of the flows estimated by the Soil and Water Assessment Tool (SWAT) model in rural watershed in the southeast of Espírito Santo state was evaluated, by changing calibration parameters, fluviometric stations, historical series and number of sub-basins involved in the process. In additionally there were verified the process of sensitivity analysis of calibration parameters and the influence of input data in the estimation of the flow rates. The results of the sensitivity analysis identified that most sensitive parameters for the study area are the same found in other studies carried out in Brazil and in its Southeast region. There were differences in the most sensitive parameters found for each type of analysis performed. The mean flows obtained by the SWAT were overestimated when compared to the observed data. Hence, it was necessary to calibrate and analyze the influence of the input data on the results. The calibration tests were performed by the SWAT-CUP program and the efficacy of each test was statistically evaluated by Nash-Sutcliffe Efficiency Coefficient (COE), Trend Percentage (PBIAS) and Mean Square Error (EQM). Calibration tests for observed series flow (29 years) from two fluviometric stations did not generate satisfactory results. The best result was obtained by changing all the calibration parameters for all sub-basins in the study area. This test was applied to short flows series (3 years) and it was possible to obtain a satisfactory calibration with COE values equal to 0.53 and 0.50, PBIAS equal to 6.60 and 20.70 and EQM equal to 0.72 and 0.69 for each fluviometric station, respectively. It is verified that the calibration process is a fine adjustment, therefore, the high overestimation simulated data makes calibration difficult, this can be associated with the quality of the input data of soil, climate, pedology and spatialization of the climatic stations in the basin.
Análise ecotoxicológica de sedimento do estuário da Baía de Vitória (ES) com diferentes granulometrias
(Universidade Federal do Espírito Santo, 2011-07-13) Santos, Andreia Carvalho dos; Rigo, Daniel; Cassini, Sérvio Túlio Alves; Paiva, Teresa Cristina Brazil de
The Bay of Vitória (ES, Brazil) comprises an important estuarine system and one of the most significant port complexes in Brazil. Port activities along with intense urbanization are responsible for environmental damages in the area, including constant dredging and landfills. The main source of contamination in the area is sewage dumping from continental drainage. This study characterizes sediments from some points of the bay according to location, granulometry, and toxicity in order to contribute to analyzing the laws regulating sediment monitoring during dredging events. During remobilization, sediment is resuspended with contaminants to the water column, which can cause impacts on both dredged and disposal areas. Sediment toxicity with different grain sizes was assessed through acute ecotoxicological testing with bacterium Vibrio fischeri, and chronic ecotoxicological testing with microalgae Skeletonema costatum. The physical-chemical analyses and tests with Skeletonema costatum were performed through elutriation, and the tests with Vibrio fischeri used interstitial water. Nine (9) different sediment collection points, with varied sand and mud contents, were selected. The results obtained from ecotoxicological testing showed correspondence between sediment toxicity and proximity to contamination sources. However, this was not found for the relation between mud content and contamination. Some collection points presented toxicity despite the fact that mud content was low (≤ 10%). This contributes to the discussion about the guidelines and proceedings in the CONAMA (Brazilian Council for the Environment) Resolution 344/04. We verified that sediments of an estuary or bay cannot be deprived from monitoring based only on grading regardless of the amount being dredged without taking the contamination and proximity to contamination sources into account
Análise fatorial em series temporais com long-memory, outliers e sazonalidade : aplicação em poluição do ar na região da Grande Vitória-ES
(Universidade Federal do Espírito Santo, 2015-07-20) Sgrancio, Adriano Marcio; Reisen, Valdério Anselmo; Zielgmann, Flávio Augusto; Reis Junior, Neyval Costa; Albuquerque, Taciana Toledo de Almeida; Bovas, Abraham; Thavanesswaran, Aerambamoorthy
Studies about air pollution typically involve measurements and analysis of pollutants, such as PM10 (particulate matter), SO2 (sulfur dioxide) and others. These data typically have important features like serial correlation, long dependency, seasonality and occurence of atypical observations, and many others, which may be analyzed by means of multivariate time series. In this context, a robust estimator of fractional robust autocovariance matrix of long dependence and seasonal frequency for SARFIMA model is proposed. The model is compared to SARMA model and is applied to SO2 concentrations. In addition of the mentioned features the data present high dimensionality in relation to sample size and number of variables. This fact complicates the analisys of the data using vector time series models. In the literature, the approach to mitigate this problem for high dimensional time series is to reduce the dimensionality using the factor analysis and principal component analysis. However, the long dependence characteristics and atypical observations, very common in air pollution series, is not considered by the standard factor analysis method. In this context, the standard factor model is extended to consider time series data presenting long dependence and outliers. The proposed method is applied to PM10 series of air quality monitoring network of the Greater Vitoria Region - ES.
Análise regional de curvas de permanência e de curvas de probabilidade de vazões mínimas: avaliação do desempenho de diferentes métodos de regionalização
(Universidade Federal do Espírito Santo, 2017-09-25) Piol, Marcos Vinícius Alpoin; Reis, José Antônio Tosta dos; Mendonça, Antonio Sergio Ferreira; Silva, Fernando das Graças Braga da
Due to Brazilian hydrological monitoring network deficiency, several hydrographic basins do not present enough data for correct and efficient National Water Resources Policy instruments implementation. Thus, methods for estimating reference flows for streams sections lacking reliable records are necessary. The present study aims to compare permanence curves and minimum flows probability curves regionalization methodologies. The considered methodologies were Characteristic Values Method and Exponential Curve Method for permanence curves regionalization and Characteristic Values Method and Parameters Method for minimum flows probability regionalization in the portions of Itapemirim and Itabapoana basins located in the southern part of Espírito Santo State and covering small portions of the territories of the states of Minas Gerais and Rio de Janeiro. In addition, regional flow indicators were used to compare the reference flow values obtained through the analyzed regionalization methods. The method that presented best results, for both permanence curve and minimum flows probability curves regionalization, was the Characteristic Values. The regional flows indicators method showed to be a simple and consistent alternative for estimating reference flows in the study area.

Navegar

Navegando Engenharia Ambiental por Assunto "628"

Resultados por página

Opções de Ordenação