Flood-Flow Characteristics Of Equatorial Natural Rivers In Sarawak, Malaysia
A study on two natural rivers during flood events located in the outskirt of Kuching city, Sarawak is carried out. This paper presents the results obtained from the field measurements, including velocity distributions, stage discharge relationships, roughness behaviours and discharge estimation. T...
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Main Authors: | , , , , , |
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Format: | E-Article |
Language: | English |
Published: |
The Institution of Engineers, Malaysia
2008
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Subjects: | |
Online Access: | http://ir.unimas.my/id/eprint/11093/1/Flood-flow%20characteristics%20of%20equatorial%20natural%20rivers%20in%20Sarawak%2C%20Malaysia%20%28abstract%29.pdf http://ir.unimas.my/id/eprint/11093/ |
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Summary: | A study on two natural rivers during flood events located in the outskirt of Kuching city, Sarawak is carried out. This paper
presents the results obtained from the field measurements, including velocity distributions, stage discharge relationships,
roughness behaviours and discharge estimation. These have illustrated a large difference in velocity between the main channel
and floodplain under flood conditions, and the effects of momentum transfer between deep and shallow flow, which include
reduction in main channel velocity and discharge capacity, leading to a reduction in compound section capacity at depth above
bankfull. Another significant characteristic for flow in natural rivers is that the floodplain regions are found to behave as a storage
reservoir instead of conveying excess water. Flow resistance relationships have been presented in terms of Manning’s coefficient
and Darcy-Weisbach friction factor, showing the complex nature of flow resistance in flooded natural rivers and further explaining
the danger inherent in the conventional practices of extrapolating inbank data for the analysis of overbank flows. Results for
discharge estimation have been shown for comparison with actual data, the errors incurred by applying empirical methods to
compound channel flows have been quantified and found to depend on the particular method used. |
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