Hydroelectric Plant Reservoir Research Articles

Seasonal assessment of water quality and eutrophication of the Tucuruí Hydroelectric plant reservoir, Pará, Brazil

No represamento de um rio, a hidrologia local sofre mudanças nas condições físico-químicas e biológica do meio aquático, podendo gerar significativos impactos ambientais. Dessa forma, este estudo teve por objetivo avaliar a qualidade da água do reservatório da Usina Hidrelétrica de Tucuruí (UHT) localizada no estado do Pará, a partir da utilização do Índice de Qualidade da Água (IQA) e do Índice de Estado Trófico (IET). A coleta de dados foi realizada no banco de dados da Secretaria de Meio Ambiente e Sustentabilidade do Estado do Pará. Os dados foram coletados para o ano de 2022, em dois períodos distintos, chuvoso e seco. Os dados foram analisados por meio de estatística descritiva e posterior elaboração de gráficos e tabelas, teste não paramétrico de Wilcoxon e interpolação espacial. A análise dos dados permitiu a elaboração de mapas com a identificação do nível de qualidade e trofia dos pontos de monitoramento a montante, a jusante e do reservatório da UHT. Os resultados indicaram que o IQA determinado nos dois períodos analisados (chuvoso e seco) apresentou maiores valores nos pontos amostrais dentro do reservatório e o menor valor no ponto a montante. O ambiente pode ser classificado como oligotrófico, caracterizado pela pobreza em nutrientes e por uma baixa taxa de produção de matéria orgânica.

The impact of a run‐of‐the‐river hydroelectric dam on a non‐volant small‐mammal assemblage in Brazilian Amazonia

AbstractThere are few scientific studies evaluating the impact of the loss of wetlands on the banks of tropical rivers on assemblages of small non‐flying mammals. To understand the possible deleterious effects of hydroelectric construction in tropical forests on this group of mammals, we used data from 2 years of monitoring carried out during the period before the filling of a hydroelectric plant reservoir in the Brazilian Amazon, and related them to vegetation, soil and topography. We captured 659 individuals of 20 small‐mammal species. The species assemblage composition in the flooded areas was a subset of species that occurred in both floodable and non‐floodable areas, and only one species was captured exclusively in the flooded area. Species composition was influenced by the proportion of sand, by soil nutrient concentration and distance from water bodies. We conclude that there is no evidence that the flooding of low‐lying areas along the Madeira River would negatively affect the assemblage of non‐flying small mammals in the short term because the remaining areas have similar assemblages of small mammals as those destined for flooding. Whether the area lost will be important for population dynamics will depend on the conservation of the remaining areas.

A comprehensive review of the environmental impacts of hydropower projects in Sarawak, Malaysia

Sarawak is a state in Malaysia that has many potential sites for hydropower dams as Sarawak houses many hilly areas which are yet to be developed. As a result, many hydropower dams were proposed in Sarawak. This paper reviews the environmental and social impacts of hydropower projects in Sarawak. The murky river waters of Sarawak contributed to a high level of sedimentation in the hydroelectric plant reservoirs which increases the emission of greenhouse gases through mineralization and indirectly affects the lifespan of a hydroelectric plant. The ecosystem is adversely affected by the loss of trees, destruction of habitat for flora and fauna, and the narrowing of rivers due to sedimentation. The construction of hydropower plants forces nearby indigenous communities to relocate, which are given compensation by the Sarawak government. The issues behind the relocation process are explored in this paper with further details. The communities that are affected by the construction of the hydropower dams will have to be displaced from their original lands; thus, the approach by the government to compensate the affected locals in Sarawak is explored in this paper.

Spatio-temporal dynamics of surface water quality of two large reservoirs of Brazilian hydroelectric plants

RESUMO A utilização de recursos hídricos na geração de energia, em geral, envolve a concepção de barragens e reservatórios artificiais, que podem estar associados a impactos socioambientais. O emprego de técnicas estatísticas e índices para a avaliação dos dados da qualidade de águas superficiais tem se mostrado eficiente na compreensão da dinâmica desses ambientes. O objetivo do trabalho foi avaliar a qualidade das águas de dois grandes reservatórios e seus principais tributários, as usinas hidrelétricas Emborcação e Nova Ponte, em Minas Gerais. Dados secundários foram avaliados por meio da técnica estatística multivariada análise de cluster (AC), seguida de testes não paramétricos, além do cálculo dos índices de conformidade ao enquadramento (ICE) e de estado trófico (IET). Para subsidiar a discussão dos resultados, os usos e coberturas da terra da área também foram analisados. Os resultados da AC indicaram a separação das estações de cada reservatório em grupos, conforme localizações e tipo de ambiente nos quais estão inseridas. Os resultados dos testes estatísticos sugeriram melhor qualidade da água nos grupos de estações localizadas no reservatório e próximas a ele, o que foi corroborado pelo ICE. Os resultados do ICE indicaram adequação da qualidade dessas águas em relação aos usos propostos para a classe 2 de enquadramento. Quanto ao IET, verificou-se presença de produtividade primária intermediária em níveis aceitáveis. A predominância do uso do solo para agropecuária pode justificar, em parte, as condições de degradação da qualidade da água dos cursos d’água, principalmente no que se refere aos parâmetros associados a sólidos e nutrientes.

CO2 and CH4 emission meter in hydroelectric plants on aquatic surface

The recent intensification of human activities has led to a significant increase in the emission of certain gases, called greenhouse gases (GHG), such as carbon dioxide (CO2) and methane (CH4). The Earth’s climate changes together through United Nations Organizations (ONU) to create strategies to reduce the impacts of gases in the Earth’s atmosphere. Of all the GHG generation activities, the energy sector is the one that most contributes to global warming, the reservoirs of hydroelectric plants are potential emitters of greenhouse gases. Considering the importance of developing new policies to slow global warming, the proposer work will help to compare the studies carried out on automated gas emission measurement tool, which allows the identification of an estimated amount of pollution in reservoirs that a hydroelectric plant is capable of to produce and emit to the atmosphere. Currently, this measurement is performed using stationary sensors manually positioned whit the aid of boats. The robotic model allows data collection through gas sensors and moves around the water surface by means of engines and guided by GPS. The prototype was applying to a reservoir at the Mourão Hydroelectric Plant in the city of Campo Mourão, Paraná, Brazil, for accurate and reliable data, it was necessary to consider parameter that influence gas measurements, such as humidity, temperature, and climate. The data collected may contribute to future studies for the development of methods for recovering water conditions, through preservation actions.

Technical feasibility study and optimisation analysis on solar biomass-based pumped storage hydropower plant

The potential of hydroelectric plants in north-eastern region is very much promising for supplying electricity. But the reservoirs of hydroelectric plants are facing water shortage during the lean season, which results in a very low power generation. Gumti Hydroelectric Plant generates power to diminish the power crisis of Tripura but it remains inoperative during the lean season due to the shortage of water. Therefore, this study proposes an advancement to Gumti Hydroelectric Plant in Tripura by designing a hybrid energy system using renewable energy sources to supply a dependable, continuous and economical power supply. This study includes optimisation analysis by utilising real-time data of renewable energy sources, which help us to understand the extent of power generation and its cost of energy. The results of this study indicate that a hybrid system is a viable option as compared to a single hydroelectric plant in maintaining the continuity of power supply.

Technical feasibility study and optimisation analysis on solar-biomass based pumped storage hydropower plant

The potential of hydroelectric plants in north-eastern region is very much promising for supplying electricity. But the reservoirs of hydroelectric plants are facing water shortage during the lean season, which results in a very low power generation. Gumti Hydroelectric Plant generates power to diminish the power crisis of Tripura but it remains inoperative during the lean season due to the shortage of water. Therefore, this study proposes an advancement to Gumti Hydroelectric Plant in Tripura by designing a hybrid energy system using renewable energy sources to supply a dependable, continuous and economical power supply. This study includes optimisation analysis by utilising real-time data of renewable energy sources, which help us to understand the extent of power generation and its cost of energy. The results of this study indicate that a hybrid system is a viable option as compared to a single hydroelectric plant in maintaining the continuity of power supply.

Macrophytes banks as potential fish nursery areas in small hydropower reservoirs

Abstract: Aim This study verified if the macrophyte banks found in two reservoirs of small hydroelectric plants (SHPs) have a functional ecological role for the initial development of ichthyofauna. Additionally, we compared the differences in the structure of the fish assemblages along each reservoir compartment and between reservoirs. Methods Sampling was performed in March 2018, in lotic, intermediate, and lentic compartments of Palmeiras and Retiro reservoirs, Sapucaí-Mirim River (SP). Three distinct macrophyte banks in each stretch (triplicates), considering the most representative in terms of composition (recurrency/dominance), were sampled, resulting in 18 samples (nine per reservoir). For fish collection we used a sieve of 1 m2 of area, mesh size of 1 mm, which was manually hauled, from the boat, in the marginal aquatic vegetation (three hauls per sample). Simultaneously, we measured basic limnological parameters with a Horiba U-52 water probe, adjacent to the banks. Results The presence of juveniles of all fish orders found in the river, Characiformes, Siluriformes, Synbranchiformes, Gymnotiformes and Cichliformes, demonstrates that, at least in certain moment of their development cycle, the macrophyte banks are used by species with different ecological requirements. It was observed significant statistical differences in the structure of the ichthyofauna along the longitudinal axes of the reservoirs, but not between reservoirs. The same was seen for the limnological data (PCA). Conclusions The macrophyte banks found in the SHPs reservoirs have a potential role as nurseries for the local ichthyofauna, mainly, but not exclusively, for sedentary species and with parental care. This association is ecologically relevant, given the absence of typical lateral habitats for the initial development of the fish fauna. Additionally, despite the reservoirs small size, spatial organization was also important for the assemblage’s structure, with differences in terms of composition, size and development stages along the distinct sampling stretches.

Monitoramento de empreendimentos hidrelétricos na bacia do rio Tocantins, Brasil: o que aprendemos com os estudos das macrófitas aquáticas

O presente trabalho teve como objetivo analisar os estudos ambientais e monitoramentos de plantas aquáticas em reservatórios de usinas hidrelétricas para discutir a respeito de uma política de manejo dessas comunidades para reservatórios existentes e futuros. Foram realizadas a revisão bibliográfica e a pesquisa documental, buscando as informações nos Estudo de Impacto Ambiental (EIA), monitoramentos de cada empreendimento hidrelétrico, livros, revistas, publicações avulsas, sites especializados e imprensa escrita, disponibilizadas na Internet ou em bibliotecas. Os documentos obtidos foram sistematizados e as informações organizadas cronologicamente por empreendimento considerando a área de abrangência dos estudos; metodologias de coleta, tempo e número de amostragem. Constatou-se que ainda existem dificuldades para o acesso a documentos em guarda de órgãos ambientais. Observou-se que os monitoramentos, principalmente no âmbito da Licença Ambiental de Operação, não estão sendo executados sistematicamente, deixando lacunas importantes em relação à composição e abundância de espécies, o que dificulta a comparação do comportamento destas ao longo do tempo. Os monitoramentos analisados empregaram diferentes métodos, o que influenciou nos resultados quando se busca a análise integrada desses estudos. É necessário criar procedimentos e definir metodologias no processo de licenciamento ambiental para sistematização dos estudos e monitoramentos, visando melhorar a acessibilidade e permitir a análise integrada dos dados.

Work and heat exchange network synthesis considering multiple electricity-related scenarios

Work and heat integration has emerged in the last decade as a promising area with a wide scope for research. Under that relatively new field, the synthesis of work and heat exchange networks (WHEN) is certainly an encouraging subject. This work presents a method for WHEN synthesis considering some aspects that were not approached in previous literature. Multiple electricity cost scenarios are considered and analyzed in the synthesis task. These are proposed according to different electricity production regimes, which are used by suppliers due to eventual changes in electricity production conditions (e.g., low level in hydroelectric power plants reservoirs). Evidently, monthly electricity prices are affected under such regimes. In the model, multiple utilities use is possible. Utilities can be modelled as regular process streams (instead of the typical approach of fixed inlet/outlet temperatures in heaters/coolers). The model also comprises the use of piecewise linear approximations for enthalpy/temperature calculations. The solution approach is an enhanced meta-heuristic method. It could be observed that considering an intermediate electricity cost scenario (between optimistic and pessimistic predictions) for the WHEN synthesis stage may lead to smaller monetary losses in case of occurrence of other scenarios.

The characteristics of seismic activity in the ladder zone of Da river hydro-electric plants

In this paper, the authors describe a study examining the characteristics of seismic activity in the ladder zone of Da river hydro-electric plants. The study results show that:- The occurrence of natural earthquakes in the ladder zone of Da river hydro-electric plants is the strongest in Vietnamese territory. An earthquake magnitude of M=6.7 has been observed in the Tuan Giao and Lai Chau areas, with a b coefficient value (Gutenberg-Richter law) of 0.935.- Natural earthquakes with magnitudes in the range of 6.0-6.9 seem to occur in 13 seismic sources, these being: Muong Te, Nam Nhe, Muong Nhe, Lai Chau - Dien Bien, Son La, Tuan Giao, Phong Tho, Muong La - Bac Yen, Song Da (Da River), Nam Tong, Mu Cang Chai, Lao Cai - Ninh Binh (Phan Sipan), and Mai Chau. Of these, an apparent risk of strong earthquakes, with a magnitude of M=6.9, appears in Muong Te, Lai Chau - Dien Bien, Tuan Giao, Yen Chau, and Mai Chau areas.- Triggered earthquakes with a magnitude M>4.0 have occurred in the region of the Hoa Binh and Son La hydro-electric plant reservoirs, which have a maximum depth of over 100 meters, and a geological structure comprising mainly limestone. - No likelihood of triggered earthquakes in the region of the Hoa Binh hydro-electric plant reservoir; however, in the Son La hydro-electric reservoir region, a triggered earthquake is expected in the future with a strong magnitude of M=4.3, or possibly even M=5.0.

The influence of a large reservoir on the reproductive activity of the white piranha, Serrasalmus brandtii (Lütken, 1875) in Southeast Brazil

Abstract: In order to assess the influence of the Três Marias dam on the reproduction of the white piranha, Serrasalmus brandtii, 1569 specimens captured from June 2011 to May 2012 in three sections of the São Francisco River basin were analyzed: section 1 = Três Marias reservoir (TMR); section 2 = São Francisco River (SFR) segment immediately downstream of TMR; and section 3 = SFR segment at the confluence with the Abaeté River. Total length (TL), body weight (BW), gonadosomatic index (GSI), and gonadal maturation stages were determined for each specimen, while vitellogenic follicle diameter, and absolute (AF) and relative (RF) fecundities were also determined for females. Reproductive activity, including spawned females and spermed males, was recorded throughout the year in the three river segments. Higher frequencies of females and males at the maturing/mature stage were found in the November/December and January/February, which coincided with the period of higher temperature, rainfall, and dissolved oxygen concentration. Mean GSI and vitellogenic follicle diameter were higher in sections 1 and 3 than in section 2 (P <0.05), while AF and RF were higher in section 1 (P <0.05) than in sections 2 and 3. The results of the present study showed that S. brandtii had lower reproductive performance in section 2, probably due to thermal disturbances caused by the dam, thus confirming the influence of dams on the reproduction of fish downstream from hydroelectric plant reservoirs.

Population structure of Macrobrachium amazonicum (Heller, 1862) (Decapoda: Palaemonidae) in Miranda Hydroelectric Plant Reservoir, Araguari river, Minas Gerais, Brazil

Abstract Aim The present study aimed to analyze a M. amazonicum population structure in a reservoir of the “Triângulo Mineiro”, Brazil. Methods Monthly surveys were carried out from April/2012 to May/2013 at the Miranda Hydroelectric Plant Reservoir located in Araguari river, state of Minas Gerais. A sampling section of 100 m long, 5 m wide and depth not exceeding 1 m was defined on the banks of the reservoir. Sampling consisted on two persons quickly passing a 2 mm sieves in partially submerged marginal vegetation, for one hour. The sampled specimens were identified, sexed and measured. Results A total of 2,584 specimens were analyzed, of which 64.62% were females (3.93% ovigerous, 5.94% non-ovigerous and 54.75% juveniles), 29.16% males (21.41% adults and 7.76% juveniles) and 6.22% juveniles of undetermined sex. The sex ratio (1:2.21) indicated a clear deviation for females, for the whole sampling period, monthly and for each size class. Males had an average carapace length (CL = 4.50 ± 0.71 mm) significantly lower than females (CL = 4.64 ± 1.47 mm) and the size frequency distribution revealed a unimodal pattern, with peaks occurring in 4.0 - 4.9 mm size class for males and in 3.0 - 3.9 mm size class for females. The relation between total and carapace length was significant, indicating a negative allometric growth. No males’ morphotypes were found. The population presented a continuous reproduction with a gradual increase between April and June/2012. Female sexual maturity was determined for 6.3 mm of CL, while for males was estimated for 4.0 mm. Conclusion The Miranda reservoir population had a body size variation similar to the continental populations of Pantanal. The sexual dimorphism observed may be related to the absence of male morphotypes and to the “pure search” reproduction strategy. The deviated sex ratio for females may increase the chance of fertilization and the reproductive success. The presence of juveniles and ovigerous females throughout the year indicates a continuous reproduction pattern of the population.

Analysis of the hydrological cycle and its impacts on the sustainability of the electric matrix in the state of Rio de Janeiro/Brazil

Between 20132015 and, the state of Rio de Janeiro, which is the second most economically important state in Brazil experienced a double crisis that incurred several consequences, including a shortage of drinking water in many cities and a reduction in hydroelectric generation. Therefore, the aim of this research was to analyze the impacts of this crisis on the state's electrical matrix from socioeconomic and socio-environmental viewpoints. The work included documental research of the data and correlations among them for the generation of electricity, the volumes of the reservoirs of hydroelectric plants, and thermoelectric and thermonuclear generation during this water crisis. Thermoelectric plants (TEP) provided 61.3% of the total installed capacity in Rio de Janeiro, thermonuclear plants (NPT) provided 23.46%, and only 14.86% originated from hydroelectric plants. During the studied period, the average power generated by the TEPs was five times higher than that recorded for hydroelectric generation. This scenario has negatively impacted the sustainability of the electric matrix, as it has resulted in high energy costs and increased greenhouse gas (GHG) emissions. However, the state could diversify its matrix in a sustainable a manner of exploiting existing wind and solar potential, thus allowing the electric matrix to follow global and national initiatives to reduce GHG emissions.

Estimation of Chlorophyll-a Concentration from Optimizing a Semi-Analytical Algorithm in Productive Inland Waters

The high nutrient concentrations coming from non-point and point pollution have been linked to algae blooms, especially in hydroelectric plant reservoirs, due to higher residence time compared to rivers. The monitoring of algae is important to prevent risk of contamination by toxins in reservoirs used for drinking water supply. In this context, a physical model-based approach was adopted to retrieve chlorophyll-a (chl a) concentration, a photosynthetic pigment found in all phytoplankton species. We assumed that a semi-analytical algorithm parameterized to a eutrophic reservoir could also be applied to other eutrophic reservoirs, at least the specific inherent optical properties (SIOPs) are not similar. The parameterization was carried out based on Ocean and Land Color Instrument (OLCI) bands aboard Sentinel-3 spacecraft. In our study, the semi-analytical approach showed good performance in retrieving chl a content, with a normalized root mean square error (NRMSE) of 18.7%. The findings encourage the use of a unique semi-analytical algorithm in a reservoir cascade, where the impoundments present similar bio-optical status. The good performance of the algorithm indicates that this approach is rather useful in predicting trophic status in reservoirs.

Quality of sediments in relation to the presence of heavy metals in the hydroelectric plant reservoir in Caçu-Goiás

Este artigo tem como objetivo analisar qualitativamente a presença de metais pesados nos sedimentos do reservatório da usina hidrelétrica Caçu (UHE Caçu). Os metais avaliados foram: Cádmio, Chumbo, Mercúrio, Cobre, Níquel e Zinco. O método utilizado foi a US EPA 3051, e as análises qualitativas foram realizadas de acordo a resolução CONAMA 454/2012. Conforme as análises realizadas, não foi detectada a presença de Mercúrio e a concentração de Chumbo encontra-se dentro dos padrões da classe I estabelecidos pela resolução vigente. 70% das amostras de Cobre, Níquel e Zinco apresentam concentrações que podem ser classificadas como de nível I e 30 % como de nível II, conforme a referida Resolução. O Cádmio apresenta altas concentrações, sendo classificado como de nível II, a partir do qual existe grande possibilidade de efeitos adversos à biota. A B S T R A C T This article aims to qualitatively analyze the presence of heavy metals in the sediments of the reservoir of the hydroelectric plant (UHE) in Caçu. The evaluated metals were: Cadmium, Lead, Mercury, Copper, Nickel and Zinc. The method used was US-EPA 3051, and qualitative analyses were performed according to CONAMA Resolution 454/2012. According to those analyses carried out, it was not detected the presence of Mercury, the concentration of Lead is within the standards of class I established by the current resolution. 70% of the samples of Copper, Nickel and Zinc presented concentrations that can be classified as level I and 30% as level II, conform the above mentioned resolution. It was found high concentrations of Cadmium, being classified as level II, from which there is great possibility of adverse effects to the biota. Keywords: toxic metals, hydrographic basin, Claro river.

Impact of the equatorial Pacific and South Atlantic SST anomalies on extremes in austral summer precipitation over Grande river basin in Southeast Brazil

ABSTRACTGrande river basin (GRB) is located in Southeast Brazil, and is socio‐economic important for water supply and electricity generation from its hydroelectric plant reservoirs affected by the inter‐annual variability of precipitation. Dry and rainy summers are selected using rainfall data from the National Water Agency (Agência Nacional de Águas–ANA) in Brazil to assess the influence of the equatorial Pacific and South Atlantic sea surface temperature (SST) anomalies, and to depict the intensity and positioning of large‐scale circulation patterns that might affect the precipitation extremes in summer over GRB. The European Centre for Medium‐Range Weather Forecasts global reanalysis provides the meteorological variables to construct the composites of the years of extremes (dry and rainy) in summer precipitation, as well as the preceding springs. The results show that extreme dry summers in GRB are characterized by neutral to negative SST anomalies in the equatorial Pacific and positive anomalies in the subtropical South Atlantic near Brazilian coastline. Rainy extremes are associated with El Niño conditions in Niño 1 + 2, Niño 3 and 3.4 regions during summer and preceding spring. Extreme rainy summers display negative anomalies of SST in the subtropical South Atlantic, coinciding with the northerly South Atlantic Convergence Zone positioning. In GRB, anomalous rainy springs are mostly followed by anomalous dry summers. Large‐scale atmospheric circulation anomalies in the preceding springs to summer precipitation extremes in GRB show characteristic features that might be proven useful in seasonal predictions of hydro‐meteorological extremes.

Richness and structure of ant assemblies (Hymenoptera: Formicidae) in Atlantic forest in southern Brazil.

Ant diversity is influenced by the structural complexity of the environment. Ants are thus an ecologically important group due to their potential to serve as indicators of environmental quality. The objective of this study was to evaluate ant diversity in areas with different land use histories and thus, within different stages of regeneration in the Permanent Preservation Area of the Foz do Chapecó Hydroelectric Plant reservoir. Ant assemblies among sample sites were compared using rarefaction analysis, and estimated richness, frequency of occurrence, and relative abundance were calculated. Associations between species and sample sites were evaluated using Principal Component Analysis (PCA). We identified 55 species in total from 24 genera, distributed among seven subfamilies. Eight species had positive associations with sample sites. Estimates indicated that ant richness may be up to 21.4% greater than that observed. This study presents an inventory of species capable of colonizing environments undergoing natural regeneration processes, and aids our understanding of ecological recovery dynamics in protected areas near hydroelectric plant reservoirs southern Brazil.

DNA barcoding as a useful tool for identifying non-native species of freshwater ichthyoplankton in the neotropics

The objective of our study was to evaluate the efficacy of DNA barcoding as a tool to identify non-native fish in their early stages of life. Specimens were collected from 14 sites in the lower and middle regions of the Paranapanema River—the main tributary of the Upper Parana River basin in southern Brazil. Over three reproductive periods from 2012 and 2015, 75 eggs and 170 larvae from 13 non-native fish species were identified. The most abundant species were Plagioscion squamosissimus (75 specimens) and Serrasalmus marginatus (68 specimens). The highest abundance was found near the Rosana hydroelectric plant reservoir. The removal of the natural physical barrier is the main reason that fish are introduced into the Paranapanema River basin with higher occurrence in the Rosana reservoir. P. squamosissimus was found in all reservoirs. DNA barcoding is a useful tool for identifying non-native fish during their reproductive phase. Furthermore, recording the presence of potentially invasive species in their early development stages may provide information useful for the rapid and effective control.

Evaluation of upper Uruguay river basin (Brazil) operational flood forecasts

ABSTRACT System for hydrological forecasting and alert running in an operational way are important tools for floods impacts reduction. The present study describes the development and results evaluation of an operational discharge forecasting system of the upper Uruguay River basin, sited in Southern Brazil. Developed system was operated every day to provide experimental forecasts with special interest for Barra Grande and Campos Novos hydroelectric power plants reservoirs inflow, with 10 days in advance. We present results of inflow forecasted for floods occurred between July 2013 to July 2016, the period which the system was operated. Forecasts results by visual and performance metrics analysis showed a good fit with observations in most cases, with possibility of floods occurrence being well predicted with antecedence of 2 to 3 days. Comparing the locations, it was noted that the sub-basin of Campos Novos, being slower in rainfall-runoff transformation, is easier forecasted. The difference in predictability between the two basins can be observed by the coefficient of persistence, which is positive from 12h in Barra Grande and from 24h to Campos Novos. These coefficient values also show the value of the rainfall-runoff modeling for forecast horizons of more than one day in the basins.