scholarly journals CARACTERIZAÇÃO DO PADRÃO DAS CHUVAS OCORRENTES EM LAVRAS, MG

Irriga ◽  
2005 ◽  
Vol 10 (4) ◽  
pp. 322-333
Author(s):  
Adão Wagner Pêgo Evangelista ◽  
Luiz Gonzaga de Carvalho ◽  
Daniel Teixeira Bernardinho
Keyword(s):  
Return Period ◽  
Rainfall Intensity ◽  
Intensity Variation ◽  
Peak Position ◽  
Maximum Intensity ◽  
Return Periods ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Erosive Rainfall ◽  
Frequency Curves

CARACTERIZAÇÃO DO PADRÃO DAS CHUVAS OCORRENTES EM LAVRAS, MG  Adão Wagner Pêgo Evangelista; Luiz Gonsaga de Carvalho; Daniel Teixeira BernardinoDepartamento de Engenharia, Universidade Federal de Lavras, Lavras, MG, [email protected]  1 RESUMO Em razão da variação da intensidade da precipitação pluvial durante a sua ocorrência, desenvolveu-se este trabalho com o objetivo de estudar os padrões de chuvas erosivas naturais verificadas em Lavras, MG, e estimar o período de retorno das chuvas em três padrões propostos. Para isto utilizou-se uma série histórica de dados pluviográficos para o período de 1987 a 1989 e 1992 a 2003, correspondente à Estação Climatológica Principal 83687 (INMET). As chuvas foram classificadas em padrão avançado, intermediário e atrasado, de acordo com a posição do pico de máxima intensidade e, posteriormente, foram calculadas as intensidades máximas de chuva para várias durações e períodos de retorno. Também foram construídas curvas de intensidade, duração e freqüência para os padrões de chuva supracitados. Com base nos resultados, pode-se concluir que o padrão de chuvas avançado se destacou em todos os parâmetros analisados, seguido em ordem decrescente pelo padrão de chuvas intermediário e atrasado. O padrão avançado correspondeu a 68% do total de chuvas analisadas, o intermediário com 22% e o atrasado com 10%. UNITERMOS: período de retorno, intensidade de chuva, perfil de precipitação.  EVANGELISTA, A.W.P.; CARVALHO, L.G. de; BERNARDINO, D.T. RAINFALL PATTERN CHARACTERIZATION IN LAVRAS, MG  2 ABSTRACT Due to rainfall intensity variation during its occurrence, this experiment was carried out in order to study the natural erosive rainfall patterns, in Lavras, Minas Gerais, Brazil, and estimate the rainfall return period for the three proposed patterns. Climatic historic pluviograph data from 1987 to 1989 and from 1992 to 2003 were used. Rainfall events were classified as advanced, intermediate and delayed, according to their maximum intensity peak position and afterwards, the maximum rainfall intensity was calculated for several durations and return periods. Intensity, duration and frequency curves for the three above mentioned patterns were also calculated. It was concluded that the advanced pattern of rainfall was more significant than all the analyzed parameters, followed by the intermediate one and the delayed pattern. The advanced pattern corresponded to 68% of the total analyzed rainfall, the intermediate one to 22% and the delayed pattern to 10% KEYWORDS: return period, rainfall intensity, precipitation profile.  

scholarly journals Duration-frequency relationships of heavy rainfall in Santa Catarina, Brazil

2012 ◽  
Vol 36 (3) ◽  
pp. 1015-1022 ◽  
Author(s):  
Álvaro José Back ◽  
José Luiz Rocha Oliveira ◽  
Alan Henn
Keyword(s):  
Return Period ◽  
Return Periods ◽  
Santa Catarina ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Rainfall Duration ◽  
Kolmogorov Smirnov ◽  
Weather Stations ◽  
The Relationship ◽  
Smirnov Test

The purpose of this study was to adjust equations that establish relationships between rainfall events with different duration and data from weather stations in the state of Santa Catarina, Brazil. In this study, the relationships between different duration heavy rainfalls from 13 weather stations of Santa Catarina were analyzed. From series of maximum annual rainfalls, and using the Gumbel-Chow distribution, the maximum rainfall for durations between 5 min and 24 h were estimated considering return periods from 2 to 100 years. The data fit to the Gumbel-Chow model was verified by the Kolmogorov-Smirnov test at 5 % significance. The coefficients of Bell's equation were adjusted to estimate the relationship between rainfall duration t (min) and the return period T (y) in relation to the maximum rainfall with a duration of 1 hour and a 10 year return period. Likewise, the coefficients of Bell's equation were adjusted based on the maximum rainfall with a duration of 1 day and a 10 year return period. The results showed that these relationships are viable to estimate short-duration rainfall events at locations where there are no rainfall records.

scholarly journals Modelling and assessment of urban flood hazards based on rainfall intensity-duration-frequency curves reformation

2016 ◽  
Author(s):  
Reza Ghazavi ◽  
Ali Moafi Rabori ◽  
Mohsen Ahadnejad Reveshty
Keyword(s):  
Return Period ◽  
Urban Areas ◽  
Rainfall Intensity ◽  
Flood Hazards ◽  
Return Periods ◽  
Urban Flood ◽  
Design Storm ◽  
Hourly Rainfall ◽  
Idf Curves ◽  
Intensity Duration Frequency

Abstract. Estimate design storm based on rainfall intensity–duration–frequency (IDF) curves is an important parameter for hydrologic planning of urban areas. The main aim of this study was to estimate rainfall intensities of Zanjan city watershed based on overall relationship of rainfall IDF curves and appropriate model of hourly rainfall estimation (Sherman method, Ghahreman and Abkhezr method). Hydrologic and hydraulic impacts of rainfall IDF curves change in flood properties was evaluated via Stormwater Management Model (SWMM). The accuracy of model simulations was confirmed based on the results of calibration. Design hyetographs in different return periods show that estimated rainfall depth via Sherman method are greater than other method except for 2-year return period. According to Ghahreman and Abkhezr method, decrease of runoff peak was 30, 39, 41 and 42 percent for 5-10-20 and 50-year return periods respectively, while runoff peak for 2-year return period was increased by 20 percent.

scholarly journals Development of Intensity Duration Frequency (IDF) Curves for Rainfall Prediction within the Middle Niger River Basin

2020 ◽  
Vol 4 (2) ◽  
pp. 382-397
Author(s):  
J. O. Ehiorobo ◽  
O.C. Izinyon ◽  
R. I. Ilaboya
Keyword(s):  
River Basin ◽  
Rainfall Intensity ◽  
Rainfall Data ◽  
Annual Maximum ◽  
Return Periods ◽  
Maximum Rainfall ◽  
Niger River ◽  
Idf Curves ◽  
Intensity Duration Frequency ◽  
Best Fit

Rainfall Intensity-Duration-Frequency (IDF) relationship remains one of the mostly used tools in hydrology and water resources engineering, especially for planning, design and operations of water resource projects. IDF relationship can provide adequate information about the intensity of rainfall at different duration for various return periods. The focus of this research was to develop IDF curves for the prediction of rainfall intensity within the middle Niger River Basin (Lokoja and Ilorin) using annual maximum daily rainfall data. Forty (40) year’s annual maximum rainfall data ranging from 1974 to 2013 was employed for the study. To ascertain the data quality, selected preliminary analysis technique including; descriptive statistics, test of homogeneity and outlier detection test were employed. To compute the three hours rainfall intensity, the ratio of rainfall amount and duration was used while the popular Gumbel probability distribution model was employed to calculate the rainfall frequency factor. To assess the best fit model that can be employed to predict rainfall intensity for various return periods at ungauged locations, four empirical IDF equations, namely; Talbot, Bernard, Kimijima and Sherman equations were employed. The model with the least calculated sum of minimized root mean square error (RMSE) was adopted as the best fit empirical model. Results obtained revealed that the Talbot model was the best fit model for Ilorin and Lokoja with calculated sum of minimized error of 1.32170E-07 and 8.953636E-08. This model was thereafter employed to predict the rainfall intensity for different durations at 2, 5, 10, 25, 50 and 100yrs return periods respectively.

Determination of Drainage Coefficient and Bund Height of Rice Fields at Gaya and Bhagalpur Districts in Bihar

2018 ◽  
Vol 5 (01) ◽  
Author(s):  
ASHUTOSH UPADHYAYA ◽  
S. K. Singh
Keyword(s):  
Return Period ◽  
Agricultural Production ◽  
Water Storage ◽  
Daily Rainfall ◽  
Crop Damage ◽  
Distribution Model ◽  
Return Periods ◽  
Maximum Rainfall ◽  
Two Parameter

Rainfall plays an important role in agricultural production, particularly in rainfed areas. Less occurrence of rainfall causes drought like situation and crops suffer due to deficit of water, whereas heavy rainfall occurring for longer duration lead to flood like situation resulting in more runoff, soil erosion and crop damage. Rice can sustain water for little longer period compared to other crops, but this crop also needs drainage. 30 years daily rainfall data was collected at Gaya and Bhagalpur districts and analyzed. Two parameter Gamma distribution model was found fitting well in 1 to 7 consecutive days maximum rainfall corresponding to return periods varying from 2 to 20 years. In order to determine drainage coefficient at Gaya and Bhagalpur districts, depthduration- return period curves were developed. Tangents were drawn on the curves from 100 mm, 150 mm and 200 mm points and slope of these tangents gave the drainage coefficients corresponding to these rain water storage levels. Since 10 years return period is generally considered in design of agricultural structures, so the poin ton Y axis, where tangent drawn on the curves of 10 years return period crosses, gives the bund height. For both Gaya and Bhagalpur bund heights were found as 24 cm and corresponding drainage coefficients as 12.5 and 25 mm/day.

DYNAMICS OF RAINFALL INTENSITY AND MESOSTRUCTURAL CHARACTERISTICS OF THEIR FIELDS IN THE WARM PERIOD OF THE YEAR IN THE PLAIN PART OF UKRAINE

2019 ◽  
pp. 95-111
Author(s):  
L. Palamarchuk ◽  
K. Sokur ◽  
T. Zabolotska
Keyword(s):  
Spatial Distribution ◽  
Rainfall Intensity ◽  
Warm Season ◽  
Maximum Intensity ◽  
Warm Period ◽  
Constant Intensity ◽  
Maximum Rainfall ◽  
Observation Network ◽  
Climatic Period ◽  
Spatial Parameters

The research deals with the structure of temporal changes in rainfall intensity and the spatial distribution of magnitude within separate processes of fallout of dangerous and heavy rainfalls in the warm season. The analysis based on the data from the Ukrainian hydrometeorological observation network (2005-2017) and the data obtained during a special scientific experiment (Kyiv, Bagrynova Mt., warm period 1969). It has been determined 97 cases of such rainfalls, the characteristics of their spatial distribution, seasonal and daily variations. For individual processes, on the basis of pluviometric measurements there were determined the maximum rainfall intensities, the time of their occurrence, the presence and the number of waves (periods) of rainfall amplification and their temporal and spatial parameters. The mass of rainwater per unit area and the volumetric intensity were calculated for moments of maximum intensity or amplification waves. The analysis of spatial and temporal fluctuations of intensity values within a separate process allowed to distinguish three types of rainfall during the warm period of the year: heavy precipitations (maximum intensities greater than 1 mm/min., such intensities more often observed at the beginning of the process; it notes the presence of one/two waves of amplification of rainfall with different amplitudes), slight precipitations (maximum intensities are approximately equal to 0.1 mm/min, several (3-5) waves of amplification of rainfall with small but equal amplitudes), and a “mix” of heavy and slight precipitations during the development of frontal stratus with so-called “flooded” convection (maximum intensities less than 1 mm / min; there are several waves of amplification of different amplitude). Conditions for the formation of heavy precipitations of the last type are the combination of mechanisms of thermal and dynamic convection, which is manifested in the enhancement of vertical lifting of air masses due to the blocking processes. It was made a comparison of the intensity and nature of precipitation in the current climatic period and in previous periods. It was found that the values of the maximum intensity for the same type of precipitation during the different observation periods practically coincide. Obviously, there is a zone of “upper limit” of the intensity of the processes of precipitation and moisture storage of clouds, which ensures the constant intensity of rainfall over time. There is some increase in number and length of waves of rainfall amplification, as well as an increase in the frequency of rainfalls with “flooded” convection. The research shows the recurrence of rainfall intensity for certain types within certain gradations of their values. On this basis an integral providing curve is created, which makes it possible to estimate the probability or recurrence of given precipitation intensity values at different levels of providing.

scholarly journals Rainfall Intensity-Duration-Frequency Relationship. Case Study: Depth-Duration Ratio in a Semi-Arid Zone in Mexico

Hydrology ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 78
Author(s):  
Ena Gámez-Balmaceda ◽  
Alvaro López-Ramos ◽  
Luisa Martínez-Acosta ◽  
Juan Pablo Medrano-Barboza ◽  
John Freddy Remolina López ◽  
...  
Keyword(s):  
Return Period ◽  
Baja California ◽  
Rainfall Intensity ◽  
Arid Zones ◽  
Return Periods ◽  
R Ratio ◽  
Idf Curves ◽  
Intensity Duration Frequency ◽  
The City ◽  
Semi Arid

Intensity–Duration–Frequency (IDF) curves describe the relationship between rainfall intensity, rainfall duration, and return period. They are commonly used in the design, planning and operation of hydrologic, hydraulic, and water resource systems. Considering the intense rainfall presence with flooding occurrences, limited data used to develop IDF curves, and importance to improve the IDF design for the Ensenada City in Baja California, this research study aims to investigate the use and combinations of pluviograph and daily records, to assess rain behavior around the city, and select a suitable method that provides the best results of IDF relationship, consequently updating the IDF relationship for the city for return periods of 10, 25, 50, and 100 years. The IDF relationship is determined through frequency analysis of rainfall observations. Also, annual maximum rainfall intensity for several duration and return periods has been analyzed according to the statistical distribution of Gumbel Extreme Value (GEV). Thus, Chen’s method was evaluated based on the depth-duration ratio (R) from the zone, and the development of the IDF relationship for the rain gauges stations was focused on estimating the most suitable (R) ratio; chosen from testing several methods and analyzing the rain in the region from California and Baja California. The determined values of the rain for one hour and return period of 2 years (P12) obtained were compared to the values of some cities in California and Baja California, with a range between 10 and 16.61 mm, and the values of the (R) ratio are in a range between 0.35 and 0.44; this range is close to the (R) ratio of 0.44 for one station in Tijuana, a city 100 km far from Ensenada. The values found here correspond to the rainfall characteristics of the zone; therefore, the method used in this study can be replicated to other semi-arid zones with the same rain characteristics. Finally, it is suggested that these results of the IDF relationship should be incorporated on the Norm of the State of Baja California as the recurrence update requires it upon recommendation. This study is the starting point to other studies that imply the calculation of a peak flow and evaluation of hydraulic structures as an input to help improve flood resilience in the city of Ensenada.

Bias introduced in rainfall risk assessment by a rain gauges network

1998 ◽  
Vol 37 (11) ◽  
pp. 97-104
Author(s):  
L. Neppel ◽  
M. Desbordes ◽  
J. M. Masson
Keyword(s):  
Risk Assessment ◽  
Frequency Analysis ◽  
Return Period ◽  
Return Periods ◽  
Rainfall Events ◽  
Rain Gauges ◽  
Spatial Approach ◽  
Rainfall Depth ◽  
Rain Gauges Network

When large periods of observation are considered, the densest information are often a collection of the daily rain gauges network. As this information is scattered in space, the stochastic results and specially the rainfall risk assessment, are biased because of the rainfall events that are not ‘observed’ by the network. Rainfall risk can be assessed using a punctual approach with the estimation of regional return period of a punctual rainfall depth exceeding a given value, or using a spatial approach with the frequency analysis of the areas of isohyets defined at a given rain threshold τ. This last approach consists, for a given τ, in estimating the return period of isohyet areas. Using simulation, a method of unbiased rainfall risk assessment is proposed for the Languedoc-Roussillon region (France). It has been shown that the bias influence is negligible for the regional return periods of isohyet areas, for 24-hour and 48-hour duration, when compared to their confident limits. On the contrary the return periods of punctual rainfall depths above a given value are more sensitive: for values above 170 mm/24h and 270 mm/48h, the biased return periods could be up to 3 times overestimated.

scholarly journals Effect of Multicollinearity on the Bivariate Frequency Analysis of Annual Maximum Rainfall Events

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 905 ◽  
Author(s):  
Yoo ◽  
Cho
Keyword(s):  
Frequency Analysis ◽  
Rainfall Intensity ◽  
Rainfall Event ◽  
Total Rainfall ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Rainfall Duration ◽  
Rainfall Depth ◽  
The Mean ◽  
Annual Maximum Rainfall

A rainfall event, simplified by a rectangular pulse, is defined by three components: the rainfall duration, the total rainfall depth, and mean rainfall intensity. However, as the mean rainfall intensity can be calculated by the total rainfall depth divided by the rainfall duration, any two components can fully define the rainfall event (i.e., one component must be redundant). The frequency analysis of a rainfall event also considers just two components selected rather arbitrarily out of these three components. However, this study argues that the two components should be selected properly or the result of frequency analysis can be significantly biased. This study fully discusses this selection problem with the annual maximum rainfall events from Seoul, Korea. In fact, this issue is closely related with the multicollinearity in the multivariate regression analysis, which indicates that as interdependency among variables grows the variance of the regression coefficient also increases to result in the low quality of resulting estimate. The findings of this study are summarized as follows: (1) The results of frequency analysis are totally different according to the selected two variables out of three. (2) Among three results, the result considering the total rainfall depth and the mean rainfall intensity is found to be the most reasonable. (3) This result is fully supported by the multicollinearity issue among the correlated variables. The rainfall duration should be excluded in the frequency analysis of a rainfall event as its variance inflation factor is very high.

Run-Off and Soil Movement on Mid-Slopes in North-East Queensland [Australia] Grazed Woodlands.

1996 ◽  
Vol 18 (1) ◽  
pp. 33 ◽  
Author(s):  
JC Scanlan ◽  
AJ Pressland ◽  
DJ Myles
Keyword(s):  
Soil Moisture ◽  
Rainfall Intensity ◽  
Sediment Concentration ◽  
Concentration Data ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Soil Movement ◽  
Heteropogon Contortus ◽  
Run Off ◽  
Soil Moisture Status

Run-off, bedload and sediment concentration data were collected over a five-year period from unbounded catchments in grazed and exclosed pastures in woodlands. Cover varied from 4% during drought conditions to almost 100% in exclosed areas after above-average rainfall. High bedload soil loss, sediment concentration and run-off percentages were associated with low cover (<30%). Run-off as a percentage of rainfall increased linearly with rainfall intensity; decreased linearly with cover; decreased slightly as soil moisture status declined; and reached a maximum at intermediate rainfall events. Interactions between these factors were observed. Run-off was up to 30% of rainfall in moderate rainfall events (30-40 mm) where maximum rainfall intensity over any 15 minute period (I15) exceeded 70 mm/h. When soil moisture status was high, mean run-off exceeded 30% for 40-80 mm rainfall events. For all rainfall event sizes, run-off exceeded 20% where I15 exceeded 60 mm/h. Cover had very little effect on run-off when rainfall intensity was low (I15<20 mm/h), soil water deficit was low (<10 mm) or when rainfall events were >75 mm or <10 mm. Bedload plus suspended sediment loads ranged from negligible to 1000 kg/ha/a, depending principally on cover. Soil movement from areas with >40-50% cover was very low. Pastures dominated by Bothriochloa pertusa (a stoloniferous, naturalised grass) had lower run-off and lower rates of soil movement than pastures dominated by Heteropogon contortus (a native tussocky perennial grass) when compared at the same level of cover. Differences between grazed and exclosed areas could be attributed solely to differences in cover.

scholarly journals Multiscale Evaluation of Extreme Rainfall Event Predictions Using Severity Diagrams

2012 ◽  
Vol 27 (1) ◽  
pp. 174-188 ◽  
Author(s):  
Davide Ceresetti ◽  
Sandrine Anquetin ◽  
Gilles Molinié ◽  
Etienne Leblois ◽  
Jean-Dominique Creutin
Keyword(s):  
Time Scales ◽  
Rainfall Intensity ◽  
Mesoscale Model ◽  
Extreme Rainfall ◽  
Space Time ◽  
Extreme Rainfall Event ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Rainfall Depth ◽  
Heavy Rainfall Events

Abstract Observations and simulations of rainfall events are usually compared by analyzing (i) the total rainfall depth produced by the event and (ii) the location of the rainfall maximum. A different approach is proposed here that compares the mesoscale simulated rainfall fields with the ground rainfall observations within the multiscale framework of maximum intensity diagrams and severity diagrams. While the first simply displays the maximum rainfall intensity of an event at a number of scales, the second gives the frequency of occurrence of the maximum rainfall intensities as a function of the spatial and temporal aggregation scales, highlighting the space–time scales of the event severity. For use in a region featuring complex relief, severity diagrams have been generalized to incorporate the regional behavior of heavy rainfall events. To assess simulation outputs from a meteorological mesoscale model, three major storms that have occurred in the last decade over a mountainous Mediterranean region of southern France are analyzed. The severity diagrams detect the critical space–time scales of the rainfall events for comparison with those predicted by the simulation. This validation approach is adapted to evaluate the ability of the mesoscale model to predict various types of storms with different regional climatologies.

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