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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/2335

Title: Regional Flood Frequency analysis for upper Omo-Gibe sub-basin
Authors: Tamiru, Gedefa
Advisors: Dr. Yilma Seleshi
Keywords: Hydrolics Engineering
Copyright: Jun-2009
Date Added: 3-May-2012
Publisher: AAU
Abstract: Accurate and reliable estimates of the magnitude and frequency of floods are critical for such activities as bridge design, flood-plain delineation and management, water-supply management, and management of water-control structures, among others.This can be done using statistical method called frequency analysis. The overall objective of the study was to find an appropriate procedure and to select suitable distribution for analysis of flood frequency at-site and regional and also to develop a relationship between scaled quantiles ( QT/Qmean) and return period T, called a growth curve for use in the upper Omo-Gibe sub-basin. In this study, at-site and regional flood frequency analysis are applied to the selected annual maximum stream flood observed at 19 gauged stations with an average of 27 record lengths of years in upper Omo-Gibe sub-basin using index flood estimation procedure. Screening of time series data (especially discharge data) were done for independence, homogeneity, and randomness using Serial-Correlation Coefficient, double mass curve and Runs test respectively. Four stations are failed to pass the above tests, namely Rabu Nr. Wolkite, Nono at Darghe, Aweitu at Jimma and Gibe Nr. Limu-Genet stations. Stations, which failed to pass these test were discarded from further analysis. Even though, there are many ways of identifying of homogeneous regions, in this study statistical homogeneity tests (convectional and L-moment based tests) have been used along with geographical similarity. Accordingly, upper Omo-Gibe sub-basin has been divided in to two homogeneous regions. The first region identified includes the Wabe, Warabessa, Kuliti, Derghe, Megecha, Gogheb, Gibe-Bako, and Walga stations and the second region compresses Gojeb- Shebe ,Gilgel Gibe-Asandabo, Gilgel Gibe-Seka , Great Gibe-Abelti , Kitto-Jimma and Bulbula- Serbo stations.
URI: http://hdl.handle.net/123456789/2335
Appears in:Thesis - Hydraulics Engineering

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