Pelotas, Brazil
Pelotas, Brazil

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do Prado G.,DEA | Faria L.C.,CDTec Engineering | de Oliveira H.F.E.,Ceres | Colombo A.,Federal University of Lavras
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2013

The effect of different trajectory angles of a gun sprinkler associated with different nozzle diameters and working pressures on the radius of throw and water distribution profile were assessed in this study. The technical characterization of the gun sprinkler was carried out at a sprinkler test bench of the Universidade Federal de Lavras, at Lavras, MG, for 24 different working conditions. In function of nozzle diameter (18 and 22 mm), service pressure (294, 392, 490 and 588 kPa) and trajectory angle (16, 22 and 28o), a potential equation was adjusted to estimate the radius of throw. Furthermore, along the radius of throw the percentage distribution of the amount of water applied was analysed. For low working pressures associated with trajectory angle of 16o, higher reductions were observed on the radius of throw; from the 28o trajectory angle, for every 3o drop of the trajectory angle the radius of throw is reduced by approximately 3.4 to 4.0%; for trajectory angles higher than 22o associated with working pressures higher than 392 kPa, the amount of water applied from the gun sprinkler is more between 60 and 80% of radius of throw.

Caldeira T.L.,PPG Recursos Hidricos UFPel | Beskow S.,CDTec Engineering | De Mello C.R.,Federal University of Lavras | Faria L.C.,CDTec Engineering | And 2 more authors.
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2015

Flood management in Brazilian watersheds must be discussed and prioritized, however, the current scenario indicates that there are gaps in hydrological information with respect to its spatial and temporal variability. The probabilistic modelling of extreme rainfall events, having as goal to extrapolate values for a given frequency and duration, can be used as an excellent tool for analysis and decision-making. The main objective of this study was to analyse the adjustment of different probabilistic models for series of annual maximum daily rainfall in Rio Grande do Sul. Series of 342 rain gauges were adjusted to 2-parameter Log-Normal, 3-parameter Log-Normal and Gumbel probability distributions and goodness-of-fit tests were based on the Kolmogorov-Smirnov and Chi-Square procedures. It was found that all the distributions presented adequate results, however, 3-parameter Log-Normal distribution had the best performance in accordance with the Chi-Square test. The parameters of probability distribution presented variability over the state and a pronounced relationship with the location of rain gauges. This suggests that regionalization of high-intensity rainfall can be employed in Rio Grande do Sul as an excellent management tool. © 2015, Departamento de Engenharia Agricola - UFCG/Cnpq. All rights reserved.

Beskow S.,CDTec Engineering | de Mello C.R.,Federal University of Lavras | Faria L.C.,CDTec Engineering | Simoes M.C.,Engineering Hidrica UFPel | And 2 more authors.
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2014

Information on stream flows in dry season is crucial in the context of water resources management, however, the existing stream flows gauging network in Brazil does not satisfy the demand of practitioners. Under these circumstances, regional analysis might be applied to estimate low stream flows at sites with no gauging or sites with little stream flow records. The objective of this study was to verify the potential of three seasonality measures applied to the evaluation of the temporal and spatial regime of low stream flows in Rio Grande do Sul, in such a way that they can be used as technical support for regionalization in hydrologically homogeneous regions. In applying the methods, Seasonality Ratio (SR), Seasonality Index (SI) and Seasonality Histogram (SH), based on historical series of 108 stream flow gauging stations, it was found that there is a pronounced seasonality of low flows in this State. Among the three seasonality measures, SI and SH were more appropriate due to specific hydrological characteristics in the state, therefore, they can be considered as relevant methodologies to delineate hydrologically homogeneous regions for the regionalization of low stream flows.

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