Considering the economic and environmental damages caused by soil loss, it is clear the necessity of information about the effect that vegetation has on soil loss rate. The present paper uses the Revised Universal Soil Loss Equation with the objective of investigating soil loss under a native vegetation recovery (Atlantic Forest) and present conditions in the Guandu river basin, located in the Southwest portion of Brazil. It was identified that reforesting 8.11% of the basin, it would promote 28.73% reduction in the mean annual soil loss compared to the actual land use. Although the paper uses a particular vegetation recovery situation (areas protected by the Brazilian Forest Code), the intention here was to clarify the role that any native vegetation protection exercises on soil loss.

This paper evaluates the calibration effectiveness for estimating monthly average flow using the SWAT model in a watershed located at Espírito Santo state in Brazil. Six methodologies were tested, which differ from each other by varying calibration parameters, size of historical series and number of sub-basins associated with the process. SWAT-CUP was used for the calibration tests and its effectiveness was analyzed by three objective functions: Percent bias (PBIAS), Nash-Sutcliffe efficiency (NSE), and Ratio of the Root Mean Square Error of measured data (RSR). Tests with long historical flow data (29 years long) did not generate satisfactory outputs. However, the best results were obtained while calibrating all parameters for all sub-basins with a data series of only 3 years long. From the results, we highlight the importance of a better description of the methodologies used in the calibration process, since different results can be obtained by the same input data.

The construction of scenarios using hydrological models can evaluate the hydrological response in watersheds, due to changes in the soil use. In this context, this study analyzed the consequences of deforestation in the hydrological behavior of the Doce River Basin, which has a drainage area of approximately 86.715 km². The basin presents problems regarding water availability, floods, indiscriminate deforestation and inadequate soil management. The Model of Large Basins (MGB-IPH) was selected, using daily data from 1990 to 2014, 11 fluviometric, 81 rainfall and 12 meteorological stations, numerical model of the land, soil maps, and use and land cover. Hydrological modeling was performed in the following steps: calibration of parameters (1990 and 2005), validation (2006 to 2014) and simulation of deforestation scenarios (2000 to 2014). It was observed that the replacement of forests by pasture caused reductions in the average annual flows, indicating a decrease in average flows in deforestation scenarios. As for the behavior of floods, deforestation caused them to increase, while the annual minimum flows reduced with deforestation. The results demonstrate the worsening that the simulated scenarios can cause in the problems already found in the basin, such as floods and water shortages, to supply the uses for which the basin is intended.

Modelos hidrológicos, como o Soil and Water Assessment Tools (SWAT), são poderosas ferramentas para o gerenciamento de recursos hídricos. Entretanto, seu uso depende de muitos dados de entrada, comumente oriundos de bases internacionais e nacionais não realísticas. Dentre os dados de entrada, informações pedológicas em níveis regionais e locais são tidas como as mais críticas de obtenção e manuseio, especialmente em regiões em desenvolvimento como o Brasil, e a carência dessas informações leva a incertezas em simulações. O presente artigo tem como objetivo apresentar os procedimentos necessários para a obtenção dos valores de cada parâmetro pedológico exigido pelo modelo SWAT para estimativa de vazões em bacias hidrográficas. Ao longo trabalho são elencados os procedimentos para obtenção dos parâmetros pedológicos para cada classe de solo e ao seguir tal metodologia, foram identificados os valores para as classes presentes na área de estudo. O estudo se aplica à bacia do rio Jucu, localizada no estado do Espírito Santo, sendo referência e base de dados a futuros estudos hidrológicos da mesma região ou de outras; em vez de usar valores pouco coerentes com a realidade local.

The uncertainties present in hydrological models have made them difficult and often impossible to apply. This work evaluated the sensitivity of input parameters in the SWAT model used for the modeling of average monthly flow-discharge in the Jucu River Basin, located in the southeast portion of the state of Espírito Santo, Brazil. Sensitivity analysis was performed using the SWAT-CUP program, which uses the SUFI-2 algorithm. Four sensitivity analysis tests differing by the length of hydrological series, number of iteration and fluviometric station locations resulted in different sensitivity levels of input parameters used in the model. In this way, the present study emphasizes the need for a greater detailing of methodological processes used in the sensitivity analysis, so that different hierarchies of parameters can be obtained through the same tool.

Mathematical modeling is an important tool for water quality studies, and the integration of water quality models with geographic information systems (GIS) is very useful for information extraction and for results interpretation. In this context, this work presents the development of a water quality model coupled with GIS (MapWindow GIS) for representing impacts of point-sourced pollutants released with distinct durations under different flow scenarios, allowing a systemic view of the entire basin, and capable of being used with low data availability. The model is called SIAQUA-IPH and uses a pollutograph convolution scheme to represent multiple discharges and confluences in the basin, based on analytical solutions of the longitudinal advection-dispersion equation. Operational tests presented a full operational performance from all technical solutions adopted, and a representation of plumes considered satisfactory in comparison to observations. Additionally, a simple sensitivity analysis is presented, that gives useful insights about the model application.

This paper presents the development of a water quality model coupled with an open source Geographic Information System (GIS) software representing the impacts of large scale pollutant releases, with a systemic view of the entire basin, and simplified tools to deal with typical data scarcity situations. In the proposed model, called SIAQUA-IPH, a methodology based on the pollutant transport equation analytical solution through a scheme of linear superposition is adopted. The paper also presents tests in which model results were compared to tracer releases experiments in the Para ba do Sul river, where promising results were obtained considering the uncertainties involved.

Este trabalho apresenta o desenvolvimento de um modelo de qualidade da água acoplado com um software livre de Sistema de Informação Geográfica (SIG) para representação de impactos causados por lançamentos de poluentes em grande escala, com uma visão sistêmica de toda a bacia hidrográfica e com ferramentas simplificadas para lidar com as condições típicas de baixa disponibilidade de dados. No modelo proposto, denominado SIAQUA-IPH, é adotada uma metodologia baseada na solução analítica da equação de transporte de poluentes por meio de um esquema de sobreposição linear. São apresentados testes em que os resultados do modelo foram comparados com experimentos de lançamento de traçadores no Rio Paraíba do Sul, com resultados promissores, considerando-se as incertezas envolvidas.

Modelos matematicos sao ferramentas que auxiliam no estudo de problemas de qualidade de agua em rios, lagos e reservatorios. Muitas vezes, o uso destes modelos em problemas de grande escala e limitado pela carencia de dados e pela dificuldade em aplicar estes modelos em sistemas hidricos de grandes proporcoes. Nestes casos, uma possibilidade promissora e a integracao de modelos de qualidade de agua com os sistemas de informacao geografica. A uniao destes dois tipos de ferramentas permite uma descricao detalhada e automatizada da regiao de interesse, facilitando tambem a interpretacao dos resultados gerados, especialmente quando os lancamentos simulados sao transientes, que envolvem muitas incertezas em relacao a extensao temporal e a localizacao dos impactos. Este trabalho apresenta o desenvolvimento de um modelo de qualidade da agua acoplado com um software livre de SIG para representacao de impactos causados por lancamentos de poluentes em grande escala, com uma visao sistemica de toda a bacia hidrografica, e com ferramentas simplificadas para lidar com as tipicas condicoes de baixa disponibilidade de dados. No modelo proposto, denominado SIAQUA-IPH, e adotada uma metodologia baseada na solucao analitica da equacao de transporte de poluentes atraves de um esquema de sobreposicao linear, ou convolucao. O trabalho tambem apresenta resultados de testes em que resultados foram comparados com experimentos de lancamento de tracadores no rio Paraiba do Sul, com resultados satisfatorios, considerando as incertezas envolvidas. Espera-se que o modelo proposto sirva para aplicacoes diversas relacionadas com avaliacao de dispersao de poluentes.

The selection of combat strategy to oil spill when multi-criteria and multi-person are involved in the decision process is not an easy task. In case of oil spill, urgent decisions must be made so that the available options of responses are activated in such a way that the environmental, social and economic impacts are minimized. In this context, the decision agents involved in the decision process are the environmental agency, a non-governmental organization (NGO), and a company that get in conflict during the decision process because each one defends its own interests. So, a consensus to reach the best viable solution is desirable. The advantages and disadvantages of different types of combat strategy should be weighted, taking into account the preferences and the different point of view of the decision agents. In this context, the process to form a consensus and to elaborate the response strategies necessarily involves a process of decision making with multi-objectives and multi-person (decision agents) so that the importance of social, economic and environmental factors is considered. In this work, the fuzzy evaluation method is applied in order to automatically find the best combat response. The method is applied to evaluate combat response to oil spill in the south coast of the Espirito Santo state, Brazil. Simulation results show the viability of the method.

The non-organized growth of cities on the coastal zones of Brazil has lead to land reclamation and occupation of mangrove areas. Besides, the Brazilian legislation considers the mangroves as a preservation area. The land reclamation produces a decrease of the water volume transported to these regions (due to the decrease in the tidal prism) and consequent modification of the hydrodynamics of adjacent water bodies. The surroundings of Vitória Island, on the State of Espírito Santo (Brazil), represent a typical case of the changes induced in the mangrove areas by land reclamation. These changes are well reported by (1989) and the main occupation is related with the construction of houses. Computational modelling is a very important tool for understanding the hydrodynamics of complex systems such as estuaries with mangrove swamps. (1980) proposed a depth average model, 2DSWAMP, to study the flow in mangrove areas. They show that currents induced by tide vary considerably in direction and intensity with the tide both on the mangrove swamps and on the mangrove creek. They also show that tide asymmetry occurred due to the flooding of the mangrove swamps and friction induced by vegetation. (1995) modeled the shallow water equations to study the tide asymmetry on the mangrove creeks. The model was applied to an ideal channel, narrow and surrounded by mangrove vegetation. Their study shows the importance of drag coefficient on tide asymmetry. (1997) verified the dynamics of currents on a mangrove densely vegetated. The currents were modeled by the 2DSWAMP model, and also by a discrete vortex model, in order to study the flow pattern around the mangrove trees. It was verified that when the tidal currents interact with the vegetation, complex flow patterns, like jets, vortices and stagnation zones, are created,. (2001) investigated the drag effects caused by mangrove trees and blockage of the flow by the vegetation. They adapted the DIVAST (Depth Integrated Velocity And Solute Transport) model to include these effects. It was observed that the drag caused by the trees reduce considerably the flow on the longitudinal direction, suggesting that the densely vegetated mangroves function are water storage areas. The results indicate that trees affect the maximum velocity both for flooding and ebb tides. (2002), using elevation and velocity data measured at Vitória Bay, shows the dominance of the ebb tide currents during the spring tides and the reduction or inversion of this dominance during the neap tides. On this work the flow patterns on the surroundings of Vitória Island are investigated, considering two scenarios. The first scenario considers the flooding of the mangrove swamps and the second, for effects comparison, do not consider the flooding effect. The main purpose of this study is to characterize the flow patterns on the surroundings of Vitória Island and evaluate the influence of the mangrove swamps on the flow pattern of this region. FERREIRA

This work uses computational modelling and tracer technique in order to study the spreading of oil patches caused by accidental oil spills. The region chosen for case study is the port area of Vitoria city in the Espirito Santo State Brazil, where field experiments using tracers were carried out and computational simulations of the spreading of oil patches originated from hypothetical accidents were made. Hydrodynamics and spreading of tracers were studied using a computational system called SisBAHIA. A 3D hydro dynamical model was used together with a Lagrangean particle-tracking model. The region covered by the study was discretised by means of the creation of a quadrangular finite-element non-structured mesh. Three field experiments using tracers were carried out in the Vitoria Port channel for the tracking of plumes generated. The influence of meteorological and oceanographic conditions such as winds and tides on the development of plume spreading was evaluated. The results from the plume tracking shows that winds greatly influenced plumes shape and direction. It was observed that winds are the main forcing in the determination of tracer plumes shape and path. Aerial photographs were taken in order to evaluate tracer plumes development, and then their areas were compared with results from oil slicks spreading experiments found in the literature. Results from this study provide means for the preparation of prevention planning and response activities for oil spills occurring in the Vitoria Bay channel. The use of computational modelling may help the simulation of scenarios that can possibly be used in the enhancement of operational safety of activities that involves loading and unloading of oil in ports in the region.

This work analyses the influence of the mangrove swamps on the hydrodynamics of Vitoria Bay Brazil. The computational model DIVAST was implemented and calibrated to the region and used to determine the flow patterns for two scenarios: i) considering the mangrove swamps and ii) without considering the mangrove swamps. Water level and velocity measurements were carried out to calibrate the model. The numerical results for spring tide show that the mangrove swamps causes an increase of as much as 50% for the values of current, when compared with those obtained for the case presenting no flood. The dominance of currents pattern obtained from the experimental data is not verified for the simulation condition without the mangrove swamps.