Flood Frequency Analysis For Sarawak Using Weibull, Gringorten And L-Moments Formula
The objective of this study is to determine the magnitude and frequency of floods for Sarawak using Gumbel distribution. Nineteen stations were selected for the study based on the criteria stated in Hydrological Procedure No. 4 (HP4). The probability plot and flood-frequency curves by Gumbel distr...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
The Institution of Engineers, Malaysia
2007
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| Subjects: | |
| Online Access: | http://ir.unimas.my/id/eprint/10207/1/Onni%20S..pdf http://ir.unimas.my/id/eprint/10207/ |
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| Summary: | The objective of this study is to determine the magnitude and frequency of floods for Sarawak using Gumbel distribution.
Nineteen stations were selected for the study based on the criteria stated in Hydrological Procedure No. 4 (HP4). The
probability plot and flood-frequency curves by Gumbel distribution of each individual station are prepared using three different
plotting position formulas (i.e. Weibull, Gringorten and L-Moments). From the results and analysis of each individual station,
Gumbel distribution based on L-Moments always give the least ratio of peak discharge of T year’s recurrence interval over mean
annual flood (QT/MAF) but at some stations, it gives unreasonable return period (T) and reduced variate (y) range. The
appropriateness of L-moments with Gumbel distribution had some limitation. It is only good for small samples data. If compared
between Gumbel distribution by Weibull formula and Gumbel distribution by Gringorten formula, the latter is better because it
gives the least ratio (which is in agreement with the literature). Therefore, it could be concluded that for some stations, LMoments
method is the best, but since L-Moments method had some limitations, Gringorten formula is still the best plotting
position method to be applied with Gumbel distribution. |
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