Characterization and disaggregation of daily rainfall in the Upper Blue Nile Basin in Ethiopia

Engida, Agizew Nigussie; Estèves, Michel

doi:10.1016/j.jhydrol.2011.01.001

Cited by 35 publications

(24 citation statements)

References 27 publications

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“…Further to that, the model incorporates distinct levels of repetitions for the generation of temporal characteristics of sequences and the intensities of pulses, reducing significantly the required computational time. Successful application of Koutsoyiannis and Onof's disaggregation scheme (2001) has been reported from Abdellatif et al (2013), Debele et al (2007), Engida andEsteves (2011), Pui et al (2012) and Segond et al (2007Segond et al ( , 2006. The single-site model was generalized for the multivariate case by Koutsoyiannis et al (2003), while the single-site Hyetos model has been employed into different hybrid schemes for the spatio-temporal disaggregation of daily rainfall (Gyasi-Agyei and Mahbub, 2007;Gyasi-Agyei and Willgoose, 1997;Gyasi-agyei, 2005;Gyasi-Agyei, 1999;Segond et al, 2006) .…”

Section: Introductionmentioning

confidence: 99%

A rainfall disaggregation scheme for sub-hourly time scales: Coupling a Bartlett-Lewis based model with adjusting procedures

Kossieris

Makropoulos

Onof

et al. 2018

Journal of Hydrology

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Many hydrological applications, such as flood studies, require the use of long rainfall data at fine time scales varying from daily down to 1 minute time step. However, in the real world there is limited availability of data at sub-hourly scales. To cope with this issue, stochastic disaggregation techniques are typically employed to produce possible, statistically consistent, rainfall events that aggregate up to the field data collected at coarser scales. A methodology for the stochastic disaggregation of rainfall at fine time scales was recently introduced, combining the Bartlett-Lewis process to generate rainfall events along with adjusting procedures to modify the lower-level variables (i.e., hourly) so as to be consistent with the higher-level one (i.e., daily). In the present paper, we extend the aforementioned scheme, initially designed and tested for the disaggregation of daily rainfall into hourly depths, for any sub-hourly time scale. In addition, we take advantage of the recent developments in Poisson-cluster processes incorporating in the methodology a 2 Bartlett-Lewis model variant that introduces dependence between cell intensity and duration in order to capture the variability of rainfall at sub-hourly time scales. The disaggregation scheme is implemented in an R package, named HyetosMinute, to support disaggregation from daily down to 1-minute time scale. The applicability of the methodology was assessed on a 5-minute rainfall records collected in Bochum, Germany, comparing the performance of the above mentioned model variant against the original Bartlett-Lewis process (non-random with 5 parameters). The analysis shows that the disaggregation process reproduces adequately the most important statistical characteristics of rainfall at wide range of time scales, while the introduction of the model with dependent intensity-duration results in a better performance in terms of skewness, rainfall extremes and dry proportions.

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Section: Introductionmentioning

confidence: 99%

A rainfall disaggregation scheme for sub-hourly time scales: Coupling a Bartlett-Lewis based model with adjusting procedures

Kossieris

Makropoulos

Onof

et al. 2018

Journal of Hydrology

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“…According to Engida and Esteves (2011), Gyasi-Agyei (2005), Paola et al (2014) and Yusop et al (2014), an alternative to circumvent this data limitation is the application of the rainfall disaggregation methodology, which allows the estimation of short-duration heavy rainfall from the annual maximum daily rainfall (hday) monitored by standard rain gauges. In this methodology, the 24-hour intense rainfall (h24h) is initially estimated from hday, as the difference between them relates to the fact that the latter corresponds to the depth observed based on a fixed interval of 24 hours, since the readings are performed daily at the same time (normally 0900 every day), while h24h relates to precipitation monitored during any 24-hour period by means of pluviographs, without fixing the beginning of the initial time (Mello et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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2017

Rev. ambiente água

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The Water Safety Plan (WSP) approach is an iterative method focused on analyzing the risks of water contamination in a drinking water supply system, from catchment to consumer, in order to protect human health. This approach is aimed at identifying and drastically reducing water contamination in the entire drinking water system, through the identification and mitigation or, if possible, elimination of all factors that may cause a chemical, physical, microbiological and radiological risk for water. This study developed a proposal of WSP for the drinking water supply system (DWSS) of Mortara, Italy, in order to understand which are the preliminary evaluation aspects to be considered in the elaboration of a WSP. The DWSS of Mortara (a town of 15,500 inhabitants, located in northern Italy) consists of three drinking water treatment plants (DWTPs), considering the following main contaminants: arsenic, iron, manganese and ammonia. Potential hazardous events and associated hazards were identified in each part of the water supply system. The risk assessment was carried out following the semi-quantitative approach. The WSP proposal for Mortara was very useful not only as a risk mitigation approach, but also as a cost-effective tool for water suppliers. Furthermore, this approach will reduce public health risk, ensure a better compliance of water quality parameters with regulatory requirements, increase confidence of consumers and municipal authorities, and improve resource management due to intervention planning. Further, some new control measures are proposed by the WSP team within this work.Keywords: arsenic, drinking water, risk assessment, risk management, water safety plan. desde a captação ao consumidor, visando à proteçãoda saúde humana. Objetiva-se identificar e reduzir drasticamente a contaminação da água em todo o sistema de água potável pela identificação e mitigação ou, se possível, a eliminação de todos os fatores que podem causar um risco químico, físico, microbiológico e radiológico para a água. Este estudo desenvolveu uma proposta de PSA para o sistema de abastecimento de água potável de Mortara (Itália), a fim de compreender quais são os aspectos de avaliação preliminar a serem considerados na elaboração de um PSA. O sistema de abastecimento de água potável de Mortara (uma cidade de 15.500 habitantes, localizada no norte da Itália) consiste em três estações de tratamento de água, considerando os seguintes contaminantes principais: arsênio, ferro, manganês e amônia. Eventos perigosos potenciais e riscos relacionados foram identificados em cada parte do sistema de abastecimento de água. A avaliação do risco foi realizada seguindo a abordagem semi-quantitativa. A proposta do PSA para o sistema de abastecimento de água potável de Mortara contribuirá para reduzir os riscos à saúde pública, assegurar um melhor cumprimento dos parâmetros de qualidade da água, dos requisitos regulamentares, do aumento da confiança dos consumidores e autoridades municipais, assim como melhorar a gestão de recursos devido ...

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“…, 2008). Alternatively, according to DAMÉ et al (2010), is to use a data series of maximum daily rain per year from where the hydrological study will be conducted, and from this, a disaggregation model (Jennings et al, 2010;HANAISH et al, 2011;ENGIDA & ESTEVES, 2011;SAFEEQ & FARES, 2011;ORSINGHER & POLITO, 2012) to obtain rain ranges at sub-daily time intervals.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the relationship intensity, duration, frequency of disaggregated daily rainfall in southern Rio Grande do Sul, Brazil

Damé¹,

Teixeira-Gandra²,

Villela³

et al. 2014

Eng. Agríc.

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ABSTRACT:The intensity, duration, and frequency relationship (IDF) of rainfall occurrence may be done through continuous records of pluviographs or daily pluviometer values . The objective of this study was to estimate the intensity-duration-frequency relationships of precipitation, using the method of daily rainfall disaggregation, at weather stations located to the southern half of the state of Rio Grande do Sul; comparing them with those obtained by rain gauge records, in places considered homogeneous from the meteorological point of view. The IDF equation parameters were estimated from daily rainfall disaggregation data, using the method of nonlinear optimization. To validate the equations confidence indices and efficiency and the "t" Student test, among maximum intensity values obtained from the disaggregated daily rainfall durations of 10; 30; 60 min and 6; 12 and 24 h and those extracted from existing IDF equations. For all studied stations and return periods, the trust index values were regarded as "optimal", i.e., greater than 0.85. The maximal intensity of rainfall obtained by daily rainfall disaggregation have similarity with those obtained by relations IDF standards. Thus, the method constitutes a feasible alternative in obtaining the IDF relationships.KEYWORDS: hydrology, daily rainfall disaggregation, heavy rain. RELAÇÃO INTENSIDADE-DURAÇÃO-FREQUÊNCIA DA PRECIPITAÇÃO PLUVIALDIÁRIA DESAGREGADA NO SUL DO RIO GRANDE DO SUL RESUMO: A obtenção da relação intensidade-duração-frequência (IDF) de ocorrência de chuvas pode ser feita mediante registros contínuos de pluviógrafos ou de valores diários de pluviômetros. O objetivo do presente trabalho foi estimar as relações intensidade-duração-frequência de chuva, utilizando a metodologia da desagregação da chuva diária, para estações localizadas na metade sul do Estado do Rio Grande do Sul, comparando-as com as obtidas mediante registros pluviográficos, em locais considerados homogêneos do ponto de vista meteorológico. Os parâmetros da equação IDF foram estimados a partir dos dados de desagregação de chuva diária, utilizando o método de otimização não linear. Para validar as equações, foram utilizados índices de confiança e de eficiência, e o teste "t" de Student, entre os valores de intensidades máximas obtidos a partir da chuva diária desagregada, nas durações de 10; 30; 60 min e 6; 12 e 24 h e aqueles extraídos de equações IDF já existentes. Para todas as estações estudadas e períodos de retorno, os valores do índice de confiança foram considerados "ótimos", ou seja, maiores do que 0,85. Os valores de intensidade máxima de precipitação pluvial obtidos por desagregação da chuva diária apresentam similaridade com os obtidos por relações IDF padrões. A metodologia de desagregação de chuva diária constitui-se em alternativa viável na obtenção das relações IDF. PALAVRAS-CHAVE:hidrologia, desagregação da chuva diária, chuva intensa.

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Characterization and disaggregation of daily rainfall in the Upper Blue Nile Basin in Ethiopia

Cited by 35 publications

References 27 publications

A rainfall disaggregation scheme for sub-hourly time scales: Coupling a Bartlett-Lewis based model with adjusting procedures

A rainfall disaggregation scheme for sub-hourly time scales: Coupling a Bartlett-Lewis based model with adjusting procedures

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Analysis of the relationship intensity, duration, frequency of disaggregated daily rainfall in southern Rio Grande do Sul, Brazil

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