Optimization of flood inundation simulation using multi-resolution Digital elevation model

Several studies have been made to improve the flood inundation simulation derived from coarser Digital Elevation Model (DEM) such as using modification spatial distribution of DEM and modification of the river cross section. All models focused on the DEM. Up until now, optimization studies of DEM...

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Main Author:	Abdul Kadir, Muhammad Azraie
Format:	Thesis
Language:	English
Published:	2022
Subjects:	T Technology (General)
Online Access:	http://eprints.uthm.edu.my/10789/1/24p%20MUHAMMAD%20AZRAIE%20ABDUL%20KADIR.pdf
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spelling	my-uthm-ep.107892024-05-13T06:53:45Z Optimization of flood inundation simulation using multi-resolution Digital elevation model 2022-05 Abdul Kadir, Muhammad Azraie T Technology (General) Several studies have been made to improve the flood inundation simulation derived from coarser Digital Elevation Model (DEM) such as using modification spatial distribution of DEM and modification of the river cross section. All models focused on the DEM. Up until now, optimization studies of DEM resolution with flood inundation distribution relationship is scarce. This is one of the key components of flood phenomenon which requires high accuracy for further action in the flood risk management. Additionally, inflow value could also be used to optimize flood inundation simulation without disturbing the coarse DEM. In this study, the relationship between DEM resolution and flood inundation prediction was determined in an attempt to propose a new optimization method of flood inundation prediction. This was established by incorporating the inflow value into the relationship between DEM resolution and flood inundation. A hydraulic model of Sungai Bertam, Cameron Highland was developed at a scale of 1:25 to conduct experiments at different inflow value. This result was used to validate the 2D numerical simulation of HEC-RAS model. Then, the high resolution DEM was resampled into several coarser DEM to re-simulate the flood inundation. Both DEM and flood inundation results (Water Surface Elevation (WSE), flood extent, and flood area) were used to determine the effect of inflow parameter on the optimization of flood inundation simulation. Additionally, the optimization was also validated experimentally using the hydraulic model. Hydraulic model experiment indicated that the geometry of the channel (shape and slope) plays an important role in flood inundation and inflow of 64 l/s provided a significant flood inundation at the downstream of the river. A good agreement between hydraulic and HEC-RAS model was found except at low inflow (25 m3/s and 50 m3/s), velocity (maximum Mean Relative Absolute Error (MRAE) = 0.408) and flow travel time (R2 = 0.595). This is due to the limitation of diffusive wave algorithm, 2-dimensional model and effect of grid configuration. Relationship between DEM resolution and WSE gave the best R2 with minimum R2 = 0.9845 at the inflow of 150 m3/s. Increasing DEM resolution also increased the Mean Absolute Error (MAE) and MRAE index. Optimization using the relationship between DEM resolution and WSE together with several inflow values gives significant improvement up to 72 % of MRAE index for flood extent and 131.53 % of MRAE index for flood area. Validation using the hydraulic model experiment at an inflow of 200 m3/s indicated that the optimization improves the MRAE index of WSE by 23%. The study concluded that flood inundation simulation can be improved by modification of the inflow parameter, as well as the correlation between DEM resolution and flood inundation prediction. 2022-05 Thesis http://eprints.uthm.edu.my/10789/ http://eprints.uthm.edu.my/10789/1/24p%20MUHAMMAD%20AZRAIE%20ABDUL%20KADIR.pdf text en public phd doctoral Universiti Sains Malaysia Pusat Pengajian Kejuruteraan Awam
institution	Universiti Tun Hussein Onn Malaysia
collection	UTHM Institutional Repository
language	English
topic	T Technology (General)
spellingShingle	T Technology (General) Abdul Kadir, Muhammad Azraie Optimization of flood inundation simulation using multi-resolution Digital elevation model
description	Several studies have been made to improve the flood inundation simulation derived from coarser Digital Elevation Model (DEM) such as using modification spatial distribution of DEM and modification of the river cross section. All models focused on the DEM. Up until now, optimization studies of DEM resolution with flood inundation distribution relationship is scarce. This is one of the key components of flood phenomenon which requires high accuracy for further action in the flood risk management. Additionally, inflow value could also be used to optimize flood inundation simulation without disturbing the coarse DEM. In this study, the relationship between DEM resolution and flood inundation prediction was determined in an attempt to propose a new optimization method of flood inundation prediction. This was established by incorporating the inflow value into the relationship between DEM resolution and flood inundation. A hydraulic model of Sungai Bertam, Cameron Highland was developed at a scale of 1:25 to conduct experiments at different inflow value. This result was used to validate the 2D numerical simulation of HEC-RAS model. Then, the high resolution DEM was resampled into several coarser DEM to re-simulate the flood inundation. Both DEM and flood inundation results (Water Surface Elevation (WSE), flood extent, and flood area) were used to determine the effect of inflow parameter on the optimization of flood inundation simulation. Additionally, the optimization was also validated experimentally using the hydraulic model. Hydraulic model experiment indicated that the geometry of the channel (shape and slope) plays an important role in flood inundation and inflow of 64 l/s provided a significant flood inundation at the downstream of the river. A good agreement between hydraulic and HEC-RAS model was found except at low inflow (25 m3/s and 50 m3/s), velocity (maximum Mean Relative Absolute Error (MRAE) = 0.408) and flow travel time (R2 = 0.595). This is due to the limitation of diffusive wave algorithm, 2-dimensional model and effect of grid configuration. Relationship between DEM resolution and WSE gave the best R2 with minimum R2 = 0.9845 at the inflow of 150 m3/s. Increasing DEM resolution also increased the Mean Absolute Error (MAE) and MRAE index. Optimization using the relationship between DEM resolution and WSE together with several inflow values gives significant improvement up to 72 % of MRAE index for flood extent and 131.53 % of MRAE index for flood area. Validation using the hydraulic model experiment at an inflow of 200 m3/s indicated that the optimization improves the MRAE index of WSE by 23%. The study concluded that flood inundation simulation can be improved by modification of the inflow parameter, as well as the correlation between DEM resolution and flood inundation prediction.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Abdul Kadir, Muhammad Azraie
author_facet	Abdul Kadir, Muhammad Azraie
author_sort	Abdul Kadir, Muhammad Azraie
title	Optimization of flood inundation simulation using multi-resolution Digital elevation model
title_short	Optimization of flood inundation simulation using multi-resolution Digital elevation model
title_full	Optimization of flood inundation simulation using multi-resolution Digital elevation model
title_fullStr	Optimization of flood inundation simulation using multi-resolution Digital elevation model
title_full_unstemmed	Optimization of flood inundation simulation using multi-resolution Digital elevation model
title_sort	optimization of flood inundation simulation using multi-resolution digital elevation model
granting_institution	Universiti Sains Malaysia
granting_department	Pusat Pengajian Kejuruteraan Awam
publishDate	2022
url	http://eprints.uthm.edu.my/10789/1/24p%20MUHAMMAD%20AZRAIE%20ABDUL%20KADIR.pdf
_version_	1804890114576351232

Optimization of flood inundation simulation using multi-resolution Digital elevation model

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