Showing papers in "Revista Brasileira de Recursos Hídricos in 2008"

Variabilidade Temporal em Longo Período da Descarga Fluvial e Níveis de Água da Lagoa dos Patos, Rio Grande do Sul, Brasil

Abstract: The influence of river discharge in the marine environment is expressed in several time scales, but in long time scales it tends to control the residual pattern of behavior of these ecosystems. Studies on the dynamics of the Patos Lagoon, located in the extreme south of Brazil, are limited to considering the effect of wind and river discharge on synoptic time scales. In this sense, the objective of the study is to investigate the time variability scale of the dominant processes over the long term in river discharge and water levels in Patos Lagoon. Several time series of river discharge, water levels and Southern Oscillation Index were used to perform the study. A polynomial model based on the least squares method was used to re-construct series of water levels and statistical analysis methods were used to determine the main cycles of variability and their possible cause and effect relationship in the variables analyzed. The time series analysis suggests that on a scale of years, the river discharge accounts for over 80% of the variability in the lagoonal portion of Patos Lagoon. The river discharge in the main tributaries and the water levels in Patos lagoon are influenced on interannual scales (cycles between 3.3 and 5 years) by El Nino Southern Oscillation. The river discharge and the water levels in the region also follow a pattern of temporal variability with a decadal scale (10.8 year cycle)., which may have been associated with El Nino Southern Oscillation events, or with other oceanic and atmospheric processes of climatic kind on global scales

Simulação da qualidade de água em grandes bacias : rio Taquari-Antas, RS

Abstract: Water resources management involves the evaluation of existing and planned scenarios for the occupation of the hydrographic basin, identifying and estimating the impacts of non-point and point sources of pollution, besides the effects of modification of the fluvial regime by hydraulic works. The aforementioned evaluation is part of planning water resources at the hydrographic basin level, from the perspective of a compromise between development and sustainability. A hydrologic and water quality model is presented which allows the simulation of intervention scenarios in large basins. The IPH-MGBq model, using precipitation data, allows the calculation and representation of time variability of discharge and concentration of DO, BOD, Simulação da Qualidade de Água em Grandes Bacias: Rio Taquari-Antas, RS 22 total nitrogen and phosphorous and fecal coliforms along the drainage network. The model was used in the Taquari-Antas river in Rio Grande do Sul, with an approximate area of 26,000 km considering the effects of agriculture, urbanization, point loads of domestic and industrial sewage, besides hydropower dams to be built and currently being built in the basin. The results were adjusted to the hydrological and water quality data available for the current scenario, and the model was used to prognosticate future scenarios of the interventions, with results appropriate to this type of analysis. Key-words: Water quality; IPH-MGBq model. RBRH — Revista Brasileira de Recursos Hídricos Volume 13 n.3 Jul/Set 2008, 23-34 23 Caracterização do Carbono Orgânico para Avaliação Ambiental da Qualidade da Água — Estudo de Caso do Lago do Parque Barigüi Alessandra T. Villa Lopardo, Cristóvão V. Scapulatempo Fernandes Programa de Pós-graduação em Engenharia de Recursos Hídricos e Ambiental UFPR alessandra.villa@gmail.com, cris.dhs@ufpr.br Júlio C. Rodrigues de Azevedo Departamento de Química e Biologia UTFPR jcrazevedo@hotmail.com Recebido: 17/04/06 — recebido: 12/12/07 — aceito: 26/06/08

Simulação na bacia Amazônica com dados limitados : rio Madeira

Abstract: Hydrological simulation of the rain-discharge transformation using a hydrological model is applied to water resources management in a number of activities such as estimate, forecast and evaluation of the hydrological processes. The large basins (> 10,000 km2 ) have many effects such as climate, geology and human activities. The Amazon is a region where there are major human impacts due to the expansion of economic development. The Hydrological Model for Large Basins (MGB-IPH) was applied in the Amazon basin in order to evaluate its potential in this basin. Different hydrological data sources were tested. Daily precipitation data were used from the hydrometeorological network of the National Water Agency (ANA) and from NCEP/NCAR re-analysis corrected by the Center for Ocean Land Atmosphere (COLA). Climatological data from the International Satellite Land Surface Climatology Project (ISLSCP) and from NCEP/NCAR reanalysis were used to calculate evapotranspiration. The model was applied in the Madeira river basin, one of the most important sub-basins of the Amazon River. The results showed that daily COLA precipitation series have values very close to ANA precipitation series for the 1979-1990 period. In the portion of the basin located outside Brazil, COLA precipitation was compared with monthly data bases. At some points in the basin we had to correct the precipitation using these data bases. The model simulations showed good quality despite the limited hydrological information in the Amazon region

Simulação Hidráulica de Trincheiras de Infiltração de Águas Pluviais

Abstract: A two-dimensional infiltration model is presented to estimate infiltrated volumes and the humid area around rainwater infiltration trenches. The model, based on Richards’ equation, was originally developed by Tabuada et al (1995) to study humid areas around the irrigation furrows. The formula uses retention and non-saturated hydraulic conductivity curves. The purpose is to provide a tool to help size the trenches to control surface runoff at the source. The model was calibrated for two soils, one with higher clay and sit content, and the other with higher sand content. A validation was performed, considering the same initial condition of saturated soil. The results showed a reduction in surface runoff because of the use of trenches, but they supplied infiltrated volumes lower than those observed. This may have occurred due to uncertainties in the retention curves, as regards non-homogeneous distribution of the pore diameters. The infiltration capacity of the trenches for volumes applied equivalent to a given design rainfall was satisfactory in the sense that it reduced the surface runoff generated on the lot, even under initial conditions of saturated soil

Previsões de Curto Prazo de Vazão Afluente ao Reservatório de Furnas Utilizando Redes Neurais Artificiais

Abstract: This study presents the evaluation of the performance of a streamflow forecast model based on a feedforward multilayer artificial neural network. Available rainfall forecasts were considered as additional inputs to the model. The Furnas dam, in the Rio Grande basin, was selected as the case study, primarily because of the availability of short-term rainfall forecast data produced in a previous study using an ETA model. Streamflow forecasts have a twelve day horizon at daily intervals (lead times from 1 to 12 days). A new methodology for training and validating the Artificial Neural Network is proposed based on perfect rainfall forecasts (considering observed rainfall as a forecast). Results show that benefits could be achieved in inflow forecasts to Furnas dam by incorporating rainfall forecasts. Improvement in inflow forecasts using the proposed model depends on quality of rainfall forecasts. However, forecast performance was better than the current streamflow forecasts produced by the Brazilian national electric system operator. The performance of the streamflow forecast model using ETA rainfall forecast and perfect forecast were similar up to the fifth lead time. Meanwhile, quality of streamflow forecasts improves when using perfect rainfall forecast from lead time six to twelve, compared to that using ETA forecast

Metodologia para o Dimensionamento de Trincheiras de Infiltração para o Controle do Escoamento Superficial na Origem

Abstract: A methodology is proposed to size infiltration trenches for surface runoff control on the lot where it is generated. The method is based on the water budget in which the inflow volume is estimated based on the idf curve and the outflow volume on the soil infiltration rate. Two methodologies are presented to estimate the infiltration rate: one based on Philip’s horizontal infiltration model and the other based on a two-dimensional model to simulate infiltration using the Richards’ equation. The models proposed were calibrated by experimental trials performed on two types of soil, one sandy and the other clayey.

Avaliação dos Benefícios de Previsões de Vazão na Operação de Reservatórios

Abstract: This study assesses incremental benefits that might be obtained from the use of short-term and long-term streamflow forecasts in the operation of a multipurpose reservoir focusing on two water uses: flood control and power generation. The Três Marias dam, in the São Francisco river basin, was selected for study, primarily because of the availability of short-term streamflow forecast data from previous work. This streamflow forecast was estimated with a distributed hydrological model that uses a combination of observed precipitation and quantitative precipitation forecast generated by an ETA regional model as input data, and it will here be referred to as real short-term forecast. In order to quantify the benefits of forecasts, two simulation models of reservoir operation were used. The first model defines reservoir operation without using forecasts. Meanwhile, the second model considers available forecasts in the reservoir operation. The time step used in simulation was one day. Operation rules, in the form of linear rulecurves were used in reservoir operation with and without forecast. The rule-curves were optimized through a parameterization, simulation and optimization approach with an evolutionary algorithm. Results with “perfect” forecasts (considering observed flows as a forecast) show that an 8% improvement in hydropower generation can occur if longterm forecasts are considered with a two-month horizon, and if the operation is set very early in advance. The operation based on short-term forecasts has less benefits, but they are still significant. For instance, a short-term forecast with a 12-day lead time performed weekly has an incremental hydropower generation of 4.45%. Those benefits were achieved without loss of flood control performance. The benefits achieved with real short-term forecasts were lower than those with perfect short-term forecasts, as expected. However, benefits were still achieved with the real shortterm forecasts, that could be 50% higher than those expected with the perfect flow forecasts and, consequently, the reduction of increased benefit is relatively small in the period analyzed. Results are promising and show clear advantages in using quantitative precipitation forecasts to perform streamflow forecasts in multipurpose reservoir

Efeito da Liberação de Nutrientes por Plantas Aquáticas sobre a Dinâmica de Estados Alternativos da Comunidade Fitoplanctônica em um Lago Raso Subtropical

Abstract: Water fluctuations may affect several ecological functions within submerged macrophyte and phytoplankton communities in shallow lakes. This may cause changes in internal nutrient cycling inducing a shift from clear water state (oligotrophic) to turbid eutrophic state dominated by cyanobacteria. Such shifts in water quality have been investigated according to the theory of alternative states in shallow lakes. The study evaluates the possibility of alternative states in Lake Mangueira (RS), a shallow subtropical system which suffers due to intensive water intake for irrigation. A drastic depletion in the water level of the system may cause the mortality of submerged vegetation and leaching of large amounts of dissolved nutrients from decaying biomass. To understand these effects in the system, experimental analysis of nutrient leaching and biomass data obtained from field survey was performed in a complex ecological model to predict possible shifts in the water state. Simulations of orto-phosphate leaching (0.02-0.06 mg L) indicated possible shifts either to a cyanobacteria dominated state or to a cover dominated by floating plants, both representing eutrophicated conditions. Analysis of phytoplankton community structure within an increasing orto-P concentration suggested a critical resilience threshold of 0.05 mg L for a cyanobacteria dominated state in subtropical lakes. Key-words: nutrient cycling, ecological modeling, water quality states.

Modelos de Previsão de Vazões para a Bacia Incremental à UHE Itaipu

Abstract: This article presents the synthesis of studies performed to apply and analyze the performance of natural streamflow forecasting models of inflows into the Itaipu Hydroelectric Power Plant. For this purpose, two distinct lines of mathematical modeling were used: hydrological modeling and linear stochastic modeling. The composition approach is also evaluated, in which the final result of the forecasting model is obtained from a linear combination of the individual results supplied by the abovementioned methodologies. The streamflow forecasting models consider the availability of hydrometeorological information in the watershed analyzed, particularly of precipitation forecasts supplied by the ETA regional meteorological model, operated by the Centro de Previsao de Tempo e Estudos Climaticos do Instituto Nacional de Pesquisas Espaciais (CPTEC/INPE-Center of Weather Forecasts and Climatic Studies of the National Institute of Spatial Research). The good results obtained by using these models show their applicability to forecasting natural flows in the incremental basin of Itaipu

Estimativa da Evapotranspiração Regional por meio de Técnicas de Sensoriamento Remoto Integradas a Modelo de Balanço de Energia

Abstract: In this work regional evapotranspiration estimates are used to analyze spatial behavior. SEBAL (Surface Energy Balance Algorism for Land), whose basic formulation is the use of the energy balance equation and the relationship between visible and thermal infrared spectral radiances of areas with sufficiently large hydrological contrast, was used. From 44 AVHRR (Advanced Very High Resolution Radiometer) images obtained from NOAA-14 satellite, and also from ground station climatic data, actual ET cover series for Rio Grande do Sul State were generated, in 1998. Some representative areas of the State’s main cover classes were chosen. They presented, in decreasing order, the following annual mean losses (mm year-1): wetland (827), lake (732), forest (686), agricultural areas (458), grassland (453) and urban area (276). The classes with the least anthropic influence had the highest ET. An axis of ET decrease in the first half year from northwest to southeast, and, afterwards, an ET increase in the second half year, in the opposite direction was observed. The verifications were done by a simplified annual water balance over some hydrologic basins. Despite the uncertainties, the methodology is valid and has a great potential, since physical formulation allows access to ET spatial distribution

Uso de Geotecnologias para Análise Espacial da Qualidade da Água no Reservatório de Barra Bonita - SP

Abstract: This work aims to present results of the performed in the Barra Bonita reservoir, in the State of Sao Paulo in 2006. This study involved spatial analysis of reservoir water quality variables (temperature, electric conductivity, dissolved oxygen, hydrogenionic concentration and turbidity) based on the drought periods (April to September) and the rainy period (October to March) using a water quality monitoring probe.. The results showed that some physicalchemical variables, such as electric conductivity and turbidity, increase significantly from the dry period to the rainy one, since they are directly related to the contribution of organic material. The dissolved oxygen increases a lot from the rainy period to the dry one, but in both the periods the biggest concentrations are found at the end of the arm of river Piracicaba - SP. The hydrogenionic potential (pH) suffers a very small variation from the dry period to the rainy one, but their values vary spatially, and higher values were found in the dam compartment for the dry period and at the end of the arm of river Piracicaba for the rainy period. The Geostatistics software (Surfer) calculated and generated trend maps indicating in which reservoir compartments the biggest concentrations of the variables analyzed were obtained

Hormônios Estrogênicos no Ambiente e Eficiência das Tecnologias de Tratamento para Remoção em Água e Esgoto

Abstract: Estrogenic hormones are steroids produced naturally by humans and animals or synthesized for application as drugs. When excreted and discharged into the environment, they show biological activity in concentrations above 1 ng L-1. Nevertheless, processes such as biodegradation, photolysis and absorption contribute to partial removal of the hormones leaching into the water sources. There is evidence that human exposure to estrogenic hormones contributes to reduction in male fertility and an increased incidence of breast cancer. For the ecological biota, the consequences are the feminization of male fish and a reduction in plant growth. While the efficiency of conventional water treatments has not been clarified, advanced treatments demonstrate removal efficiencies of over 90%. Sewage treatment shows different efficiencies for the removal of these substances

Balanço hídrico do bota-fora BF4 da mina de Urânio Osamu Utsumi, como subsídio para projetos de remediação de drenagem ácida.

Abstract: ...........................................................................................................................VI ÍNDICE...................................................................................................................................VII LISTA DE FIGURAS ............................................................................................................... IX LISTA DE TABELAS ..............................................................................................................XI LISTA DE SIGLAS E SÍMBOLOS..........................................................................................XII CAPÍTULO 1............................................................................................................................ 1 CONSIDERAÇÕES INICIAIS ................................................................................................... 1 CAPÍTULO 2............................................................................................................................ 7 DRENAGEM ÁCIDA ................................................................................................................ 7 2.1 – INTRODUÇÃO ................................................................................................................................. 7 2.2 – TÉCNICAS DE DISPOSIÇÃO DOS RESÍDUOS DE MINERAÇÃO......................................... 9 2.3 – MINERAIS ENVOLVIDOS NA GERAÇÃO DE DRENAGEM ÁCIDA.................................. 11 2.4 – REAÇÕES DE GERAÇÃO DE DAM POR OXIDAÇÃO DA PIRITA..................................... 12 2.5 – REAÇÕES DE NEUTRALIZAÇÃO............................................................................................. 14 2.6 – A ATUAÇÃO MICROBIOLÓGICA ............................................................................................ 15 2.7 – LIXIVIAÇÃO DE METAIS PESADOS ....................................................................................... 17 2.8 – FATORES INTERVENIENTES ................................................................................................... 19 2.9 – PREVISÃO DE DAM ..................................................................................................................... 21 2.10 – TÉCNICAS DE PREVENÇÃO E TRATAMENTO.................................................................. 22 CAPÍTULO 3.......................................................................................................................... 28 A MINA OSAMU UTSUMI E O BOTA-FORA BF4.................................................................. 28 3.1 – LOCALIZAÇÃO............................................................................................................................. 28 3.2 – FINALIDADE ................................................................................................................................. 28 3.3 – CONTEXTO GEOLÓGICO.......................................................................................................... 30 3.4 – ASPECTOS FÍSICOS, CLIMÁTICOS E HIDROLÓGICOS .................................................... 33 3.5 – HISTÓRICO DA MINA OSAMU UTSUMI ................................................................................ 34 3.6 – GERENCIAMENTO DO PROCESSO MINERÁRIO................................................................ 36 3.7 – PRODUÇÃO DE MINÉRIOS E RESÍDUOS............................................................................... 37 3.8 – O BOTA-FORA BF4....................................................................................................................... 40 3.9 – DRENAGEM ÁCIDA E CUSTOS ENVOLVIDOS..................................................................... 43 CAPÍTULO 4.......................................................................................................................... 47 BALANÇO HÍDRICO E SEUS COMPONENTES.................................................................... 47 4.1 – INTRODUÇÃO ............................................................................................................................... 47 4.2 – CICLO HIDROLÓGICO............................................................................................................... 47 4.3 – EQUAÇÃO DO BALANÇO HÍDRICO........................................................................................ 49

Avaliação de Metodologia de Estimativa de Produção de Sedimentos em uma Pequena Bacia Rural de Encosta

Abstract: M.S. Dissertation Post Graduation Program on Civil Engeneering Universidade Federal de Santa Maria, RS, Brazil EVALUATION OF METHODOLOGY TO ESTIMATE OF SEDIMENTS PRODUCTION IN A SMALL AGRICULTURAL BASIN OF SLOPE Author: Raquel Maldaner Paranhos Advisor: João Batista Dias de Paiva Place and Date of Defense: Santa Maria, 22 of may of 2003. The erosion, by runoff, consequently the production of sediments, has been object of increasing concern in all the relative situations the management of the use of the soil and the water. The main objective of this work is to analyze the routing methodology of Williams (1975) associate to the model rainfall-runoff IPH II applied to the basin Menino Deus II, in Santa Maria RS Brazil. The purpose of this methodology is the determination of the sediment routing coefficient B, for the basin in study. For in such a way, the flow and sediment stage-discharge relation of the basin in study were determined. Secondary objective was to analyze the possibility of the use of the turbidity for the determination of the concentration of sediments. From observed data the stage-discharge relation of sediments were plotted, getting relations, considered satisfactory for these curves, of 99.8% for the average data of the sediment sampler ANA; 98,9% for the average data of sediment sampler AND; and 97% for sediment sampler AMS1 in ascent and 85,7% descending, so now it'is possible the estimate of the discharge solid of sediments. The conclusion about the turbidity data, was that is possible to determine the concentration of sediments only from turbidity data lower tham 500 NTU. The routing methodology of Williams (1975) adapted well to the basin in study. It was obtained a relation between the product of runoff and peak flow and the coefficient of propagation B, that gives for an event any, the respective coefficient. The aplication of this equation to another events results in good values, with a coefficient of correlation between the measured production and the calculated of 92%. This indicates that the equation supplies resulted satisfactory in the estimate of the coefficient of propagation B the catchment Menino Deus II.

Os Efeitos no Ambiente Marinho da Elevação do Nível do Mar em Regiões da Baixada Santista, Brasil

Abstract: The greenhouse effect and resulting increase in the earth’s temperature may accelerate the mean sea level rise. Knowledge regarding the relative sea-level rise and its effects on coastal areas is reviewed here. Hydraulic processes, such as tidal forcing, prism, currents and storm surges, salinity intrusion and littoral processes, will be modified. The natural response of bays and estuaries to this rise, such as this case study on Santos (SP), will include change in shoreline position, land flooding and impacts on wetlands

Variabilidade Espacial da Umidade do Solo em Neossolo Flúvico

Abstract: Aiming to evaluate the spatial variability of soil moisture, an experiment was performed in the town of Pesqueira, Pernambuco State, on a carrot (Daucus carota L.) totalizing 96 days. Two irrigation sectors (1 e 2) were formed, each one with 900 m2 (30 x 30 m), adopting microsprinkler irrigation, using water of an “Amazonas well”. Twenty-three days after sowling (DAS) dead cover was added in sector 2. Water supply was based on the crop needs adding a leaching fraction of 20%. Access tubes for a neutron probe were installed to measure the soil moisture at the depths of 20 and 40 cm, at 49 points in sector 1 and 52 points in sector 2, in 5 x 5 m grid. The reading were performed an hour after the end of irrigation, twice a week, totalizing 20 days of monitoring during the crop. The data were evaluated for statistics and geostatistical methods. Sector 2 presented significantly higher moisture for two depths in almost all cycles. Spatial dependence was observed on all monitoring dates, sectors and dephts except sector 1(20 cm) from 23 to 40 DAS

Tipologia Fluvial da Bacia Hidrográfica do Rio Salgado - Sul da Bahia

Abstract: The Salgado river watershed is remarkable for the high content of dissolved salts in its water, with remarkable heterogeneity of the salinity values in the river water. The definition and spatial distribution of the hydrochemical types were based on the physical-chemical analysis, the dissolved salts content in the water samples collected in the area studied and on the multivariate statistical analysis performed. Based on the experimental results obtained, four hydrochemical types were defined: hydrochemical type I presented average salinity levels (610 μS/cm); hydrochemical type II presented low salinity levels (142 μS/cm), both types being characterized as fresh water and finally hydrochemical types III and IV presented high salinity levels (1.590 and 2.964 μS/cm respectively). The water of the Salgado river watershed had a basic-neutral pH and could be classified as mixed chloride. Key-words: hydrochemistry; multivariate analysis; Salgado river watershed; salinity.