Modelling overbank flows in rivers – data, concepts, models and calibration

Floods are the most common natural disasters in Malaysia and have damaged structures, infrastructures, crops and even causes fatalities. It may also lead to erosion and sedimentation in rivers and this will result to complex river behaviour. A hydraulic laboratory experimental study was carried out. Also, flood flow and sediment transport in straight compound channels involving flow resistance, distribution of depth-averaged velocity, stream-wise vorticity patterns, channel bed morphology and bed load transport rate in non-vegetated compound straight mobile bed channels were investigated. The finding showed that the Darcy Weisbach friction factor f increased by 40% and 54% for floodplain and main channel, respectively when relative flood flow depth increase from 0.30 to 0.50. The small bed load transport rates of 0.09 g/s and 0.03 g/s for shallow and deep overbank flows, respectively were measured due to effect of very gentle or mild channel bed slope which was fixed at a gradient of 0.1%.

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Improving bridge afflux prediction for overbank flows

Proceedings of the Institution of Civil Engineers - Water Management ◽

10.1680/wama.2008.161.5.253 ◽

2008 ◽

Vol 161 (5) ◽

pp. 253-260 ◽

Cited By ~ 3

Author(s):

G. Seckin ◽

D. W. Knight ◽

S. Atabay ◽

N. Seckin

Keyword(s):

Overbank Flows

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Coupling of a one-dimensional river routing model and a three-dimensional ocean model to predict overbank flows in a complex river–ocean system

Applied Mathematical Modelling ◽

10.1016/j.apm.2013.01.003 ◽

2013 ◽

Vol 37 (9) ◽

pp. 6163-6176 ◽

Cited By ~ 9

Author(s):

Wei-Bo Chen ◽

Wen-Cheng Liu ◽

Chung-Yi Wu

Keyword(s):

Three Dimensional ◽

Ocean Model ◽

One Dimensional ◽

Overbank Flows ◽

River Routing

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Experimental and computational aspects of overbank floodplain flow

Transactions of the Royal Society of Edinburgh Earth Sciences ◽

10.1017/s0263593300011251 ◽

1987 ◽

Vol 78 (4) ◽

pp. 315-325 ◽

Cited By ~ 34

Author(s):

D. A. Ervine ◽

J. Ellis

Keyword(s):

Energy Dissipation ◽

Numerical Modelling ◽

River System ◽

General Description ◽

Meandering Channels ◽

Complex Process ◽

Overbank Flow ◽

Flow Situation ◽

Computational Aspects ◽

Overbank Flows

ABSTRACTThe propagation of a flood wave through a river system is influenced by a complex process of energy dissipation. This is especially the case when overbank flows are a feature of the flood movement, producing more defined lateral movement of flow and high rates of fluid shear at the main channel/floodplain interface. The present paper concentrates on the physical and numerical modelling of river flows during overbank flow. A general description of the flow behaviour is outlined, including an investigation into the nature of the shear interaction between channel and floodplain. The paper advances a method for determining energy losses for the case of meandering channels with overbank flow and a method of sub-dividing the floodway for stage-discharge prediction. A state-of-the-art study of numerical modelling of flood propagation is outlined, including selected case histories on how the overbank flow situation has been handled to date, as well as comment on the current means of representing energy dissipation relying on calibration of the numerical model against observed field data.

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