Programa de Pós-Graduação em Engenharia Civil - PPGEC/ITEC

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2303

O Programa de Pós-Graduação em Engenharia Civil (PPGEC) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA) foi aprovado pela CAPES em 1999 e teve sua primeira turma iniciada em 2001, sendo o primeiro Curso de Mestrado Engenharia Civil na Região Norte do Brasil, realizando atividades integradas de Ensino, Pesquisa e Extensão nas áreas de Engenharia Civil e Engenharia Sanitária e Ambiental.

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Agora exibindo 1 - 19 de 19

Acesso aberto (Open Access)
Aplicação da RUSLE a uma pequena bacia hidrográfica da Amazônia
(Universidade Federal do Pará, 2013-09-26) SANTOS, Diego Benvindo Oliveira; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
The Amazon is experiencing severe changes due to anthropogenic activities, among which the transformation of forested land into areas for agricultural use stand out, intensifying erosion processes. Erosion, especially the drag of particles by runoff, causes a reduction of soil fertility impairing agricultural productivity and impacting the quality and quantity of surface water resources, a fact compounded by strong rainfall and naturally poor soils in the region. In this context, knowledge of erosion processes, such as through the use of mathematical models for predicting soil loss helps in determining management practices for sustainable use of natural resources. This study aimed to evaluate the applicability of the empirical model RUSLE (Revised Universal Soil Loss Equation) in the region, which considers the interaction between the rain energy, soil and topography characteristics, as well as the uses and management practiced. This research applied the RUSLE in the upper basin of the Igarapé da Prata stream, with an approximate area of 37 km², located in the municipality of Capitão Poço, Pará, Brazil, approximately 160 km from the capital Belém, in Pará Northeast region. This research also consisted in the construction of a geo-referenced database made from public sources; such data passed through adaptations for insertion into the environment of the ArcGIS to quantify the parameters of RUSLE, which when combined allowed the generation of a map of soil loss for the study area. The small upper basin of Igarapé da Prata presented soil loss values ranging between 0.004 and 72.48 t/ha year, with an average value of 5.12 and a standard deviation of 6.97, where approximately 12% of its total area presents environmental risks due to erosive processes.
Acesso aberto (Open Access)
Avaliação de modelos de inteligência artificial híbridos na estimativa de precipitações
(Universidade Federal do Pará, 2022-03-18) GOMES, Evanice Pinheiro; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
The hydrological analyzes carried out from rainfall in the Amazon are essential due to its importance in climate regulation, regional and global atmospheric circulation. However, in this region, there are limitations related to data series with short periods and many flaws, especially in the daily scale. Despite significant advances in science and technology, practical and accurate predictions have been a major concern due to their complexity. Therefore, several conceptual models, empirical or hybrid, have been tested to forecast rain with greater precision. Among empirical models, those that incorporate artificial intelligence (AI) methods are potentially useful approaches to simulate the precipitation process. Artificial Neural Networks (ANN), as AI models, are able to establish a relationship between historical inputs (rain, flow, etc.) and the desired outputs, through a non-linear function composed of several factors that are adjusted to the observed data, allowing your prediction. Thus, to improve the precipitation analysis, hybrid models were developed, involving Artificial Neural Network (ANN) of the type with Time Delay (TDNN), ELMAN network, Radial Base network (RBF) and Adaptive Neuro-Fuzzy Inference System (ANFIS), coupled with Maximum Overlap Discrete Wavelet (MODWT). Six rainfall gauge station were adopted, which are located in different biomes of the region, and satellite data (CMORPH). Rainfall data were evaluated by seasonal periods (rainy and dry). The results obtained demonstrated that the MODWT-ANFIS model had the best capacity to simulate the daily precipitation of the evaluated rainfall gauge station, even for dry periods, which are known to be more difficult to be simulated in relation to the rainy periods. In this case, data entries lagged by 4 days and 5 days performed better, with Nash values close to 1.0 and root mean square errors below 0.001.
Acesso aberto (Open Access)
Cenário das outorgas de lançamento de esgoto concedidas em Belém-Pa
(Universidade Federal do Pará, 2017-11-09) RODRIGUES, Suzana Teixeira; PESSOA, Francisco Carlos Lira; http://lattes.cnpq.br/8031687016215046; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
Conditions of effluent disposal grants authorized by the Department of Environment and Sustainability (SEMAS) of the Municipality of Belém PA, Brazil, between 2013 and 2016, are analyzed. Current study is divided into three parts: (1) collection of data retrieved from the Department; (2) preparation of a map showing effluent disposal grant sites at present; (3) number of non-computerized effluent discharges for each urban water basin in the municipality of Belém. Results showed that there are 24 effluent water disposal grants in the municipality of Belém: 62.5% are effluent disposal grants to residential housing estates; 25% are effluent disposal grants for industries; 12.5% are effluent disposal grants for other sectors, including hospitals and airport. The water resource with the greatest number of disposal sites is the Igarapé/Canal de Val-de-Cans, with five effluent disposal grant sites, followed by Igarapé São Joaquim/São Raimundo, with four effluent disposal grant sites. Very few effluents are treated at tertiary level, with disinfection prior to release in the water body. In fact, most Treatment Stations lie at the secondary level, since only organic matter is removed. However, enterprises with septic tanks and filters are still extant. Results also demonstrate that the urban water basin with the greatest unaccountable effluent discharge is the Bacia do Una, with 44,680.32 m³/day, followed by the Bacia do Outeiro, with 28,567.20 m³/day. Data are the SEMAS´s official numbers and they do not reveal the true conditions of the water bodies. In fact, there are several other effluent discharges which have not been regulated by the department and which contribute towards unbridled pollution caused by sheer lack of a comprehensive sewerage system in the municipality of Belém.
Acesso aberto (Open Access)
Contribuição à classificação de pequenas bacias hidrográficas em função da área de drenagem
(Universidade Federal do Pará, 2018-05-25) SANTANA, Laila Rover; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
The adoption of an area value to define large, medium or small river basins should take into account the various processes involved in the basin behavior. In small basins, rainfall-flow conversion phenomena are described using simpler techniques. In order to classify small river basins according to their drainage areas, the main objective of this study was to identify and classify the small basins of the Amazon using a simple linear model (MLS). The model is applied to the rainfall and flow data from selected test basins in order to verify the linearity between these variables. The MLS used in this study is based on a linear and time invariant system that establishes a cause and effect relationship between rainfall and flow data. The performance of the model was evaluated through the RMS (square root of the mean square error), and from the results, small hydrographic basins were classified as a function of the drainage area. The method of Otto Pfafstetter is applied searching to identify at what level of codification are found only small river basins. The results indicated that in the basins with drainage areas less than or equal to 620 km², the adjustment between the observed and simulated flow duration curves was higher, presenting RMS values below 3 m³ / s. In the basins with dimensions over 620 km ², the RMS results exceeded 4 m³ / s, and the flow duration curves did not present a good fit, demonstrating that the MLS fails when applied to the hydrological data of these basins. Thus, the small hydrographic basins of the Amazon were classified with areas of drainage less or equal to 620 km ². The Ottocoding method was applied until level 9, where 51,319 ottobacias were delimited, all classified as small basins.
Acesso aberto (Open Access)
Contribuição à Regionalização de Vazão Mínima de Referência na Amazônia Legal
(Universidade Federal do Pará, 2016-10-25) BARROS, Calina Grazielli Dias; PESSOA, Francisco Carlos Lira; http://lattes.cnpq.br/8031687016215046; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
Studies aimed at knowledge flows in ungauged sites, are of great importance in hydrology, because almost always the hydrometric network does not cover all areas of interest. Therefore, it is necessary to use techniques that allow the transfer of local information monitored for ungauged sites. In this context, this paper proposes mathematical models to determine the remaining flow in the Amazon, using the regionalization method of flow. The methodology was based on the minimum flow Q95% obtained from the flow duration curve plotted based on the Weibull equation, in addition to morphoclimatic characteristics of river basins, such as the drainage area (A), average annual precipitation (P) and the river length (L). The data used for regionalization belong to six hydrologically homogeneous groups analyzed in the study. With this information, and in order to define which explanatory variables (A, P and L) would be part of the models to be applied, the multi-colinearity test was performed. Thus, taking the result of the previous test, the mathematical models of regionalization of the minimum reference flow Q95% were constructed through multiple regression models (linear, potential, exponential and logarithmic).In the first analysis, the performance values (mean absolute percentage errors, determination coefficients, adjusted coefficient of determination) were unsatisfactory. For this reason, it was chosen to divide the hydrologically homogeneous groups according to the interval with the same order of magnitude of areas and flows. In this way, the results obtained in the adjustment of the models presented a better performance, which can be verified by the average absolute error below 13.78% in all groups. The models that obtained the best performance were selected for the validation, observing in this way, that the linear model was the one that presented the best results for nine of the groups and subgroups tested, standing out also the potential and logarithmic models, that simulated six of the subgroups each.Thus, from the regional equations that presented good results, both in the adjustment and in the validation, we can obtain the flow rate Q95%, in a basin without flow data according to the homogeneous regions or groups determined in the study, having as data of The physical and climatic characteristics of this basin.
Acesso aberto (Open Access)
Desenvolvimento de uma metodologia para implantação de centrais maremotrizes: aplicação na costa atlântica do Pará
(Universidade Federal do Pará, 2014-10-06) OLIVEIRA, Luciana Leal Pimentel; MESQUITA, André Luiz Amarante; http://lattes.cnpq.br/1331279630816662; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
It presents a methodology for deploying tidal plants, which were modeled phenomena and parameters needed for basic studies project. The chosen study area was the Atlantic Coast Pará. Thus, a simplified model is proposed to represent the reservoir. This model was validated with the results obtained from the bathymetry held in the estuary of Bacanga in São Luís, Maranhão, Brazil. In addition to the reservoir modeling, tidal heights were shaped by the Hermitian interpolation process. The diameter of the turbine was determined by correlations available in literature. The flow resulting from the height of variation between the sea and the reservoir caused by tidal variations, was determined by Hazen-Williams formula. The modeling of the reservoir and the tide high, more methods of determining the diameter of the turbine and the flow, allowed the determination of the installed capacity and energy generated at each site studied, which were classified as small, medium and large size. Subsequently, the cost analysis was performed for each location, including investment cost, operation, maintenance and unit energy cost. The investment cost of tidal power in comparison with other energy sources, is high. However, the unit cost of energy is much lower than the unit cost of energy of its main competitor in the region, the diesel generators. The modeling of the three cases mentioned above and your energy costs and generated results show that tidal power has the potential to be exploited in the Atlantic Coast of Pará.
Acesso aberto (Open Access)
Estimativa de sedimentos em suspensão utilizando um perfilador acústico de correntes por efeito doppler
(Universidade Federal do Pará, 2019-03-28) OLIVEIRA, Pablo Abreu de; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
In the management of water resources it is of fundamental importance to know the behavior, quality and quantity of sediments transported in river environments. These sedimentometric data are useful in defining various aspects and problem solving of water resources engineering. ADCP (Acoustic Doppler Current Profilers) is a new technology for flow and velocity measurements in rivers through acoustic waves, which may also be covered in sediment concentrations. In this context, the objective of the present work is to verify the applicability of the use of ADCP as an alternative for suspended sediment measurements. For this, the method of Gartner (2002) was used, calibrating its equation with the concentrations obtained by the point sampling method, collected with a bottle of Van Dorn in the Guamá river. The method used to obtain CSS (Suspended Sediment Concentration) with ADCP data resulted in a good estimate of concentrations, supported by the above calibration. There was a good correlation between the sediment concentration measured and the estimated 0.68 for point CSS and 0.81 for the vertical CSS. Through analyzes of the generated data we may affirm that the ADCP may also be used to measure suspended sediments in an indirect way from the return of the acoustic signal.
Acesso aberto (Open Access)
Estimativas de curvas IDF e curvas de permanência na Amazônia sob a influência de mudanças climáticas
(Universidade Federal do Pará, 2021-02-05) COSTA, Carlos Eduardo Aguiar de Souza; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
The impacts on global water resources may be more intense due to climate change, making access to water more difficult and, consequently, maintaining life. In the Amazon, the effect may be even worse, as it is one of the regions most vulnerable to these changes. Representative Concentration Pathways (RCPs) scenarios are essential tools for General Circulation Models (GCMs) and Global Hydrological Models (GHMs) to simulate future climate change. Intensity, Duration and Frequency (IDF) curves and flow duration curves are fundamental for the elaboration of hydraulic projects and risk management. Thus, the objective of this study was to elaborate projections of IDF curves for the Tapajós watershed in RCP 4.5 and 8.5, using data from GCMs HadGEM2-ES, CanESM2 and MIROC5. Another objective was to analyze variations in the permanence curves and available volumes of the Amazon River using data from the GHM WaterGAP2 forced by MIROC5 and HadGEM2-ES (in RCPs 6.0 and 8.5). The projected IDF curves were compared with the existing IDF, elaborated using a stationary method. The base permanence curves were created from the last 20 years of observed flows and compared with the curves of future scenarios (from 2020). They were calculated from decadal volumes. The biggest differences for the projected IDF curves were in MIROC5 (143.15% in RCP 8.5) and the smallest differences were in HadGEM2-ES (4% in RCP 4.5) both for the 100-year return period. The spatial resolutions of each GCM influenced their IDF curves, since CanESM2 did not present satisfactory results and MIROC5 was the one that best represented the possible future differences. WaterGAP2 presented the classification “Very Good” for most stations according to statistical validation indicators. Most of the extreme flows were for 2080 to 2099. For WaterGAP2 (MIROC5), most volumes were below the century's decadal average, increasing from 2060. For WaterGAP2 (HadGEM2-ES) projections the volumes are usually close or below the decadal average, falling from 2060 onwards. MIROC5 is the most suitable for studies of climate projections in the Amazon.
Acesso aberto (Open Access)
Influência da variabilidade climática das chuvas sobre a erosividade
(Universidade Federal do Pará, 2016-08-26) COSTA, Carlos Eduardo Aguiar de Souza; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
One of the main models to evaluate soil loss by erosion is the "Universal Soil Loss Equation" (USLE), where the determination of the erosive potential is the product of various indexes, including erosivity of rain (R). Through the R, it is possible to identify when you have the greatest risk of water erosion. In addition, it is important to study how climate change influence in this factor, noting possible tendencies to erosive events. Thus, this study aimed to analyze the influence of climatic anomalies, ENSO (El Niño Southern Oscillation) and Atlantic Dipole on erosivity of rainfall in Belém, PA. It has been calculated the monthly erosivity 1986 series to 2015, classifying them as to intensity; qualification events ENSO in the same time period, through the index of oscillation of the Niño (ION); It was found that the occurrence of the Atlantic Dipole through TNA indexes (Tropical Northern Atlantic) and TSA (Tropical Southern Atlantic), obtaining the inter-hemispheric gradient (IHG). With these data, Pearson correlation analysis and linear regression analysis between the erosivity and the ION and IHG have been carried out. It was observed that the potential erosive rainfall is affected by the ENSO phenomenon, so that a greater number of months had less erosive potential in El Niño years. In La Niña years, noted increased levels of erosivity due to the increase in precipitation, but not representative. The years of occurrence of Negative Dipole showed strong correlation, this leads to the conclusion that this phenomenon probably has more influence on the erosivity. The Positive Dipole showed little correlation with the erosive potential. It was concluded that the erosivity has undergone changes, showing effects that not only repeated but also showed strong correlations with climatic indexes.
Acesso aberto (Open Access)
Influência das mudanças climáticas no balanço hídrico dos lagos de abastecimento de Belém-PA
(Universidade Federal do Pará, 2022-05-06) SILVA, Fabíola Souza da; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
Climate change, projected for global water resources, drastic changes in patterns of distribution and availability of water. So, the objective of this study was to investigate the impacts that climate change will have on the local hydrological cycle. And analyze if the lakes Bolonha and Água Preta, responsible for supplying part of the city of Belém-PA, will be able to provide water to future demand. Then, the water balance of the lakes was projected until 2100, using the GCMs MIROC5 and HADGEM2-ES aligned to the RCM Eta, from two greenhouse gas emission scenarios RCPs 4.5 and 8.5. It was necessary to carry out the projection of the population of the city of Belém-PA until the year 2100, using the Gompertz model. The results projected a large reduction in the volume of precipitation in the rainy months compared to historical data; and for the summer period, the projections point to drier months than normal. The surface evaporation projection showed an increase in the evaporated surface volume. The consequences of the projections on the future water balance of the lakes were a high reduction in the volume of both, interfering in the recovery of their maximum capacities. The projections of future scenarios for the lakes showed that the actual production of COSANPA will not be able to meet the future demand of society, causing a situation of water scarcity until the end of the century, will lead to the need to increase the pumping of water to the lakes. In this way, understanding how changes in hydrological variables will affect water availability is an important tool in the quest to mitigate impacts and carry out long term planning and management of this resource.
Acesso aberto (Open Access)
Modelagem estocástica de função cumulativa de probabilidades de precipitação diária na região hidrográfica tocantins-araguaia (RHTA)
(Universidade Federal do Pará, 2019-03-28) PROGÊNIO, Mayke Feitosa; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
Knowing the temporal and spatial behavior of the probability of occurrence of rainfall is indispensable for the planning and management of agricultural and agroindustrial activities. However, in some river basins the available historical precipitation series are generally short and with a large number of faults, which makes statistical analyzes difficult. Thus, the objective of the work was to develop a stochastic model of cumulative function of daily precipitation probabilities in the Tocantins Araguaia hydrographic region (TAHR). The model is of the parametric type, in which precipitation occurrences were determined through the first-order Markov chain (MC) and the precipitation quantities were estimated by 4 cumulative probability functions (CPFs): exponential simple, exponential a two parameters, mixed exponential and gamma. The parameters of the CPFs were estimated by the Maximum Likelihood Method. The simulation process was performed separately for each rainfall station, without considering the spatial correlation between them. The developed model was applied in 196 rainfall stations distributed in 3 homogeneous regions (HR) of precipitation in TAHR. The results showed that the MC of the 1st order was able to reproduce satisfactorily the amount of dry and rainy days. However, in areas heavily influenced by long series of drought, the results were not satisfactory. In relation to the estimated precipitated quantities, the Kolmogorov-Smirnov (KS) test and the probability-probability (P-P) graph showed that the mixed exponential was the one that presented better adherence to the observed data for most months of the year, with the exception of the less rainy months of June, July and August in RH II and RH III, and in the months of September, October and November for RH I, for which the gamma function was more efficient, these results were also confirmed by the low Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) values. Thus, the model developed showed to be efficient in the estimation of average daily rainfall in TAHR, in addition, the use of more than one CPF gave the model greater capacity to estimate rainfall in different locations and seasons.
Acesso aberto (Open Access)
Modelo vazão-velocidade para avaliação de potencial hidrocinético
(Universidade Federal do Pará, 2018-05-25) CRUZ, Josias da Silva; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
The Brazilian hydrological information network provides daily flow data; however, daily velocity information is not available in historical series. The inventory of river velocities is important for many applications, and one of them is the study of hydrokinetic potential, including downstream of hydroelectric plants. Therefore, the work proposes a model called Flow-Velocity that determines the average daily velocity, the geometric form and the distribution of the logarithmic velocity profile of the cross section of rivers from daily flow data. The model was initially applied in a small river basin with flow data and the validation was performed using the mean square error (RMSE), the relative mean square error (RRMSE), the standard deviation of observation (RSR) and the percentage of bias PBIAS. Subsequently, the model was applied to the river basins of the Amazonas, São Francisco and Paraná rivers (Brazil's largest basins), using the highest and lowest flows in the historical series. The highest and lowest average speed found in the Amazon River was 2.27 ms-1 and 0.735 ms-1 in the Óbidos cross-section for a flow of 266 897 m³s-1 and 72 480 m³-1, respectively. The main contributors to the Amazon River, with the exception of the Trombetas, Madeira and Xingu rivers, present average daily speeds below 2 ms-1 for the flood period, but in the dry season the average daily speeds of all are below 0.5 ms-1. The São Francisco river, in the transversal sections studied along its length, presents velocities between 3.09 ms-1 to 1.68 ms-1 for the period of flood and in the period of drought the speeds are between 0,44 ms-1 to 0,12 ms-1. In the Paraná River, velocities are between 2.17 ms-1 to 1.50 ms-1 and 0,59 ms-1 to 0,12 ms-1 for the greater and smaller flow, in due order. It was verified that the Amazon river has hydrokinetic potential that can be explored all year round. In the São Francisco basin, it is only in the period of higher flows that there is potential for the installation of hydrokinetic turbines, similar to the Paraná river basin. Of course, at points in rivers where there are hydroelectric plants, this assessment should change due to the dispatch of power plants.
Acesso aberto (Open Access)
Modelo WEPP para estimativa da produção de sedimentos em uma pequena bacia hidrográfica da Amazônia
(Universidade Federal do Pará, 2017-12-06) SAMPAIO, Liliane da Cruz; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
Erosive processes produce several economic and environmental damages. The development of mathematical models has made it possible to quantify these processes, allowing estimating the magnitude of the problem, in order to minimize it. In this sense, this work uses the WEPP (Water Erosion Prediction Project) model to simulate the sediment yield in an Amazon small catchment, igarapé da Prata catchment, located in the Municipality of Capitão Poço-PA. The calibrated main parameters of the WEPP model were: initial soil saturation (Si), erosion by runoff (Ki), erosion by channel or groove flow (Kr) and saturated hydraulic conductivity (Ke). After the calibration, it was verified that most of the sediment yield is in the plans. And as is to be expected, this production is higher in areas with predominance of agriculture and livestock. The results of the estimated sediment yield calculated by the model were compared to the observed data for the year 2012. The model presented a value of 131.99 t / km², close to the observed value, which was 121.64 t / km2. This result leads to the conclusion that the values calculated by the model are consistent with the reality of the sediment yield of the small catchment in question.
Acesso aberto (Open Access)
Modelos empíricos para estimativa de produção de sedimentos
(Universidade Federal do Pará, 2015-03-20) SILVA, Danielle Sebastiana dos Santos; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
The erosive processes that occur in a watershed have been objects of concerns associated with the planning and management of land use and water resources. In this case, the empirical models of hydrosedimentological simulation are important tools, and with low cost, in the assessment of soil erosion due to the use and management of land. Thus, the study aimed to analyze the sediments yield via three empirical models applied to a small catchment of the Amazon, the catchment of Igarapé da Prata located in the municipality of Capitão Poço-PA. The analyzed and used models were the USLE (Universal Soil Loss Equation); the Poesen model; and the Langbein-Schumm model. The results showed that the USLE model had an average sediment yield equal to 146.20 (t / km²); the Langbein-Schumm model an average production equal to 114.25 (t / km²); and the Poesen model an average yield equal to 7.57 (t / km²). The results obtained by the two first-mentioned models are of the same order of magnitude, indicating that the Langbein-Schumm model, for the case analyzed, is comparable to the classical model USLE. These results were compared with observed data of suspended sediments and the Langbein-Schumm model was the one closest to the observations.
Acesso aberto (Open Access)
Probabilidade de ocorrência de chuvas e sua variação espacial e temporal na bacia hidrográfica do Rio Tapajós
(Universidade Federal do Pará, 2017-06-30) SANTOS, Vanessa Conceição dos; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
Studies of the probability of rainfall and its spatial and temporal variation are important in the planning of agricultural activities and water resources engineering. However, statistical analyzes related to rainfall find limitations regarding the size of the available historical series, which are mostly insufficient or have a large number of faults. A good alternative to overcome these limitations is the generation of pluviometric series through the use of stochastic models. In this sense, the objective was to elaborate a methodology to determine the probability of occurrence of dry and rainy days and to estimate daily average rainfall. Thus, the determination of the occurrences was done using first order Markov Chains and two states and, for the quantities, the cumulative probability distributions Gamma and Weibull were used, whose parameters were estimated by both the Maximum Likelihood Method and By the Method of Moments. The developed model was applied to 80 rainfall stations distributed in the Tapajos River Basin (TRB). The results of the probabilities of occurrence of dry and rainy periods defined for the TRB the dry season from May to September and the rainy season from October to April. The elements of the probability transition matrix and the alpha and beta parameters showed variability in relation to time and, in addition, the influence of the geographic position of the rainfall station on the determination of dry and rainy periods in specific localities. The validation of the model was performed using the Kolgomorov-Smirnov adhesion test, which demonstrated that the average daily rainfall can be estimated with good performance through the first order Markov Chain and two states with the Gamma and Weibull distribution to two Parameters. However, the Gama distribution stood out in the estimation of average daily rainfall for most of the months of the year, except for the months of March, July and December, for which the Weibull distribution proved to be efficient.
Acesso aberto (Open Access)
Proposta de otimização de modelo de regionalização de curvas de permanência de vazões
(Universidade Federal do Pará, 2014-05-16) SILVA, Raimunda da Silva e; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
Due to lack of data flow in the State of Pará, the regionalization of streamflow duration curves, presents itself as an important technique, allowing the estimation of flow in sites with insufficient or no data. Hus, this paper aims to propose the optimization of a model of regionalization of streamflow retention curves for the Para region. The model was based on data at 43 gauged stations distributed in the state of Pará. The flow duration curves were calibrated using 5 regression models: power, exponential, logarithmic, quadratic and cubic. Regionalization model was established using the multiple regression technique. The spatial variation of each parameter was explained in terms of the drainage area, mean annual precipitation, length and slope of the main river. The model was validated using the Jack -knife procedure. The best fit of the cubic model was mathematically represented by the quadratic mean relative errors (ϵ%), coefficients of Nash-Sutcliffe (Nash) and the graphics settings the simulated and observed streamflow. The optimization model was achieved by insertion of synthetic stations and cluster stations by drainage area. The number of synthetic stations included in the model were evaluated by Root Mean Square Error (RMSE), the coefficient of Nash and the ϵ%. For groups I and II the optimal number of synthetic stations, who joined those already considered in the groups, it was 6 and 3, respectively. In group III only the clustering method in relation to drainage areas was sufficient for good performance of the regionalization model. The good performance of the calibrated, validated and optimized model demonstrated the potential of this in the estimation of retention curves of the rivers that cross the Para. The geographic coordinates of synthetic stations, which optimized the model can serve as a suggestion to the government where to install new stations. The number of new stations would be limited to the results of optimization, streamlining resources and building up the model developed to determine retention curves flow for the entire state of Para. In this case, the new installed stations, would also help in the future to improve the model performance.
Acesso aberto (Open Access)
Redes neurais recorrentes para modelagem chuva-vazão de pequenas bacias hidrográficas amazônicas
(Universidade Federal do Pará, 2022-04-29) MENDONÇA, Leonardo Melo de; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
Rainfall-runoff models can help the management of water resources, especially in the Amazon, a region marked by the low density of hydrological monitoring, and thus benefit the multiple uses of water and the adequate use of water resources. This work seeks to simulate daily streamflows of five small catchments in the Amazon, through the Autoregressive Recurrent Nonlinear Neural Network with Exogenous Variable (RNN-NARX). Daily rainfall and streamflow data were used for simulation. The cross-correlation and partial auto-correlation functions helped to determine lagged data, relevant inputs, with a significance level of 5%. In addition, the Levenberg-Marquardt error backpropagation algorithm was used for supervised training of RNN-NARX. Five statistical indices and Garson's relative contribution of each input variable were also used to evaluate the simulations. Thus, the simulated flows were classified between unsatisfactory and very good, in addition to showing a general tendency to underestimate floods. The autoregressive characteristic of each catchment is fundamental for better results, quality attributed to the water storage capacity. A plausible explanation for the main sources of uncertainty is due to the spatial variability of precipitation between monitoring stations and the precipitations occurring in the catchment, meteorological anomalies and discretization aspects. The sensitivity analysis of the models against different training intervals showed that the implementation of 2 years, for the supervised training of the RNN-NARX, is sufficient to obtain efficient simulations in four of the five small Amazon catchment analyzed.
Acesso aberto (Open Access)
Regionalização de precipitações via fuzzy C-means
(Universidade Federal do Pará, 2017-04-05) GOMES, Evanice Pinheiro; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
The knowledge of the precipitation behavior is indispensable, since any change in its quantity and spatial and temporal distributions have an important impact on nature and consequently on the various human activities. However, in precipitation studies, the lack of rainfall monitoring, generating the lack of information over time and spatially in the river basins is a problem for the understanding of this variable. In order to overcome this problem, the rainfall regionalization method was proposed. The main idea was to divide the Tocantins Araguaia - RHTA hydrographic region into homogeneous regions, defined by the Fuzzy C-means method. The Euclidean distance was adopted as a measure of similarity and the fuzzification parameter, ranging from 1.2 to 2.0, and the explanatory variables of rainfall (altitude, latitude and longitude) were used as input data. Three homogeneous regions were obtained, which were validated by the PBM index and the heterogeneity test. The frequencies of observed rainfall events were generated for the 83 rain gauge stations, distributed in their respective regions, and calibrated by the Normal, Log-Normal, Gama, Gumbel, Exponential, Logarithmic and Weibull probability functions. With the application of the chi-square test, we defined the best probability function in the occurrence of rainfall in each homogeneous region. The validation of the probabilities functions was performed in 9 target stations, using the chi-square test. In this stage, it was observed that for annual average precipitation, data adherence occurred to all the rain gauge stations, since they presented results of the chi-square test of less than 5.99 (for Log-normal distribution functions). It was also observed that for monthly average precipitation, data were adhered to all the rainfall stations with the Gama and Weibull functions. For the simulation of rain depth, Linear, Potential, Exponential and Logarithm models were tested through the multiple regression method, using as independent variables, altitude, latitude and longitude. As performance criterion of the models, the R², R²_a, E%, ε%, NASH and RMSE were used. In the simulation of annual averages, the Linear model presented the best performance indices. In the estimation ofviii monthly averages, all multiple regression models did not perform well, with errors above 50%, which motivated the estimation of monthly rainfall for rainy and dry periods. In this new approach the regression models presented excellent performance criteria with errors below 10%. The performance indexes allowed us to conclude that the regional models developed for the homogeneous regions of rainfall, defined by the Fuzzy C-Means method, are a good option in the estimation of annual and monthly average rainfall and are important for a better understanding of the rainfall regime in RHTA, and can serve as a tool for better planning of water resources in the region.
Acesso aberto (Open Access)
Viabilidade econômica de sistemas de captação de água da chuva para fins não potáveis em dois prédios da Universidade Federal do Pará
(Universidade Federal do Pará, 2018-03-08) CARDOSO, Raisa Nicole Campos; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
With increasing global demand, it is important for government entities to seek water supply alternatives for sustainable use in order to minimize the consumption of potable water for uses that do not have to be potable in public buildings, and thus comply with environmental sustainability criteria required by Normative Instruction No. 01/2010 of the Ministry of Planning, Budget and Management (MPOG). Therefore, the main objective of this work is to study the economical feasibility of incorporating a system of rainwater harvesting in two higher education buildings of the Federal University of Pará (UFPA), one supplied by the Water Treatment Station (WTS) of the university and another by the local municipal water utility. For the sizing of the reservoir, the computational method Neptune 4.0 was used to obtain an ideal volume that meets the demand efficiently and is economically viable. This method is based on behavioral models, and the input data needed for the algorithm are: historical daily precipitation; the initial discharge volume of first rains; catchment area; the number of inhabitants in the building; the daily demand for water per capita; the percentage of drinking water to be replaced by rainwater; the coefficient of surface efflux; necessary information for the dimensioning of the volume of the upper and lower reservoirs. The simulation determines a relationship between drinking water saving potential and reservoir volume, according to the volume range inserted in the input data of the simulation, the percentage of service demand, rainwater consumption, and the extravasated volume. In addition to modeling the sizing, the Neptune Algorithm enables an economic analysis considering the indicators: Net Present Value (NPV), Internal Rate of Return (IRR) and Discounted Payback. To determine the demand, information was obtained on the consumption habits of the occupants of the LAESA and EMUFPA buildings, types of sanitary appliances, among other information. The result for LAESA indicated that 76% of the water consumption is destined for non-potable purposes, such as washing of the building, sanitary discharge and urinals, with 73% destined only for sanitary devices. In the EMUFPA, non-potable consumption represents 69%, with 52% destined to toilet uses and urinals. The Neptune software presented an optimum tank volume of 10.000 L for LAESA and 8.000 L for EMUFPA, with a mean drinking water saving potential of 100% and 87,34%, respectively. At EMUFPA, the system was viable, with a 10-year return on invested capital, with an internal rate of return of 1.08% per month. In LAESA, considering the supply of ETA, there was no financial return within the horizon analyzed. In the hypothetical simulation, assuming that LAESA was supplied by COSANPA, the return on invested capital would be 6 years and 4. The internal rate of return would be 1.80% per month. From the qualitative analysis, it is concluded that using rainwater in public buildings that do not subsidize water from utilities, there is a financial return, since the water supplied to the public sector is expensive. This demonstrates the importance of public buildings to comply with sustainability criteria in order to save on public expenditures, since the wasting of water in public buildings is very high, mainly due to users not paying directly for the use of Water. In addition, it is important that public and private entities incorporate within their management the concept of water security, which establishes seeking for guarantees for water availability for various uses and to take advantage of rainwater as a sustainable way to reduce the pressure for water us away from water sources, such as aquifers.