Mathematical Modeling for Flood Mitigation: Effect of Bifurcation Angles in River Flowrates

Iskandar Shah Mohd Zawawi,Nur Lina Abdullah,Hazleen Aris,Muhammad Haris Fadzillah Mohd Yunos,Badrul Amin Jaafar,Nur Arif Husaini Norwaza

doi:10.13189/cea.2019.071406

Abstract

This paper investigates the river flowrate at two branches of bifurcated river. The mathematical model from the literature is formulated based on momentum principle and mass continuity to cope with river flowrate at different bifurcation angles. The hydraulic variables, geometric properties of trapezoidal cross-sectional river and other physical characteristics of bifurcated river are provided, which may be assumed to be given beforehand for practical applications. An example of river bifurcation problem is given by UTM Centre for Industrial and Applied Mathematics (UTM-CIAM), Universiti Teknologi Malaysia. Maple software is used to implement the proposed model equation and generate the results. The amount of bifurcated river flowrate with different bifurcation angles is determined, resulting in a reasonable discussion. It is shown that for specific bifurcation angles, the river flowrates after the bifurcated junction are less than the critical flowrate. Finally, the results of applied problem indicate that the right-angled river bifurcation would be preferable to mitigate flood.

Highlights

River bifurcation is the process that determines the distribution of flo w, sediments and contaminants along the downstream river branches
Q1 becomes greater than the critical flowrate when θ=1 θ=2 900
Fro m the results obtained, it can be observed that the right-angled bifurcat ion at one of the branches would be efficient to reduce the amount of flo wrates in channel 1 significantly

Summary

Introduction

River bifurcation is the process that determines the distribution of flo w, sediments and contaminants along the downstream river branches. This process is important in order to mitigate flood due to climate change. There have been several approaches in investigating the river bifurcation or bifurcated open-channel flow. [1] used both analytical and experimental ways to study the bifurcated open-channel flow. The estimat ion of the flowrate ratio in terms of the Froude number and the depth ratio had been obtained using theoretical model in [2]. The authors provided the experimental data for the validity of their proposed model

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Conclusion