Impacts of spatial resolution and representation of flow connectivity on large-scale simulation of floods
Global-scale river models (GRMs) are core tools for providing consistent estimates of global flood hazard, especially in data-scarce regions. Due to former limitations in computational power and input datasets, most GRMs have been developed to use simplified representations of flow physics and r...
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doaj-1986a86bcbec457e85942c0e52ecf70b2020-11-24T22:41:38ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382017-10-01215143516310.5194/hess-21-5143-2017Impacts of spatial resolution and representation of flow connectivity on large-scale simulation of floodsC. M. R. Mateo0C. M. R. Mateo1D. Yamazaki2D. Yamazaki3H. Kim4A. Champathong5J. Vaze6T. Oki7T. Oki8CSIRO Land and Water, ACT, 2601, AustraliaInstitute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, JapanInstitute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, JapanDepartment of Integrated Climate Change Projection Research, Japan Agency for Marine-Earth Science and Technology, Yokohama, 236-0001, JapanInstitute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, JapanRoyal Irrigation Department, Bangkok, 10300, ThailandCSIRO Land and Water, ACT, 2601, AustraliaInstitute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, JapanUnited Nations University, 5 Chome-53-70 Jingumae, Shibuya, Tokyo, 150-8925, JapanGlobal-scale river models (GRMs) are core tools for providing consistent estimates of global flood hazard, especially in data-scarce regions. Due to former limitations in computational power and input datasets, most GRMs have been developed to use simplified representations of flow physics and run at coarse spatial resolutions. With increasing computational power and improved datasets, the application of GRMs to finer resolutions is becoming a reality. To support development in this direction, the suitability of GRMs for application to finer resolutions needs to be assessed. This study investigates the impacts of spatial resolution and flow connectivity representation on the predictive capability of a GRM, CaMa-Flood, in simulating the 2011 extreme flood in Thailand. Analyses show that when single downstream connectivity (SDC) is assumed, simulation results deteriorate with finer spatial resolution; Nash–Sutcliffe efficiency coefficients decreased by more than 50 % between simulation results at 10 km resolution and 1 km resolution. When multiple downstream connectivity (MDC) is represented, simulation results slightly improve with finer spatial resolution. The SDC simulations result in excessive backflows on very flat floodplains due to the restrictive flow directions at finer resolutions. MDC channels attenuated these effects by maintaining flow connectivity and flow capacity between floodplains in varying spatial resolutions. While a regional-scale flood was chosen as a test case, these findings should be universal and may have significant impacts on large- to global-scale simulations, especially in regions where mega deltas exist.These results demonstrate that a GRM can be used for higher resolution simulations of large-scale floods, provided that MDC in rivers and floodplains is adequately represented in the model structure.https://www.hydrol-earth-syst-sci.net/21/5143/2017/hess-21-5143-2017.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
C. M. R. Mateo C. M. R. Mateo D. Yamazaki D. Yamazaki H. Kim A. Champathong J. Vaze T. Oki T. Oki |
spellingShingle |
C. M. R. Mateo C. M. R. Mateo D. Yamazaki D. Yamazaki H. Kim A. Champathong J. Vaze T. Oki T. Oki Impacts of spatial resolution and representation of flow connectivity on large-scale simulation of floods Hydrology and Earth System Sciences |
author_facet |
C. M. R. Mateo C. M. R. Mateo D. Yamazaki D. Yamazaki H. Kim A. Champathong J. Vaze T. Oki T. Oki |
author_sort |
C. M. R. Mateo |
title |
Impacts of spatial resolution and representation of flow connectivity on large-scale simulation of floods |
title_short |
Impacts of spatial resolution and representation of flow connectivity on large-scale simulation of floods |
title_full |
Impacts of spatial resolution and representation of flow connectivity on large-scale simulation of floods |
title_fullStr |
Impacts of spatial resolution and representation of flow connectivity on large-scale simulation of floods |
title_full_unstemmed |
Impacts of spatial resolution and representation of flow connectivity on large-scale simulation of floods |
title_sort |
impacts of spatial resolution and representation of flow connectivity on large-scale simulation of floods |
publisher |
Copernicus Publications |
series |
Hydrology and Earth System Sciences |
issn |
1027-5606 1607-7938 |
publishDate |
2017-10-01 |
description |
Global-scale river models (GRMs) are core tools for providing
consistent estimates of global flood hazard, especially in data-scarce
regions. Due to former limitations in computational power and input datasets,
most GRMs have been developed to use simplified representations of flow
physics and run at coarse spatial resolutions. With increasing computational
power and improved datasets, the application of GRMs to finer resolutions is
becoming a reality. To support development in this direction, the suitability
of GRMs for application to finer resolutions needs to be assessed. This study
investigates the impacts of spatial resolution and flow connectivity
representation on the predictive capability of a GRM, CaMa-Flood, in
simulating the 2011 extreme flood in Thailand. Analyses show that when single
downstream connectivity (SDC) is assumed, simulation results deteriorate
with finer spatial resolution; Nash–Sutcliffe efficiency coefficients
decreased by more than 50 % between simulation results at 10 km
resolution and 1 km resolution. When multiple downstream connectivity
(MDC) is represented, simulation results slightly improve with finer
spatial resolution. The SDC simulations result in excessive backflows on
very flat floodplains due to the restrictive flow directions at finer
resolutions. MDC channels attenuated these effects by maintaining flow
connectivity and flow capacity between floodplains in varying spatial
resolutions. While a regional-scale flood was chosen as a test case, these
findings should be universal and may have significant impacts on large- to
global-scale simulations, especially in regions where mega deltas exist.These
results demonstrate that a GRM can be used for higher resolution simulations
of large-scale floods, provided that MDC in rivers and floodplains is
adequately represented in the model structure. |
url |
https://www.hydrol-earth-syst-sci.net/21/5143/2017/hess-21-5143-2017.pdf |
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