A framework of integrated hydrological and hydrodynamic models using synthetic rainfall for flash flood hazard mapping of ungauged catchments in tropical zones
Flash flood hazard maps provide a scientific support to mitigate flash flood risk. The present study develops a practical framework with the help of integrated hydrological and hydrodynamic modelling in order to estimate the potential flash floods. We selected a small pilot catchment which has al...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-05-01
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| Series: | Proceedings of the International Association of Hydrological Sciences |
| Online Access: | https://www.proc-iahs.net/373/183/2016/piahs-373-183-2016.pdf |
| Summary: | Flash flood hazard maps provide a scientific support to mitigate flash flood
risk. The present study develops a practical framework with the help of
integrated hydrological and hydrodynamic modelling in order to estimate the
potential flash floods. We selected a small pilot catchment which has already
suffered from flash floods in the past. This catchment is located in the Nan
River basin, northern Thailand. Reliable meteorological and hydrometric data
are missing in the catchment. Consequently, the entire upper basin of the
main river was modelled with the help of the hydrological modelling system
PANTA RHEI. In this basin, three monitoring stations are located along the
main river. PANTA RHEI was calibrated and validated with the extreme flood
events in June 2011 and July 2008, respectively. The results show a good
agreement with the observed discharge data. In order to create potential
flash flood scenarios, synthetic rainfall series were derived from temporal
rainfall patterns based on the radar-rainfall observation and different
rainfall depths from regional rainfall frequency analysis. The temporal
rainfall patterns were characterized by catchment-averaged rainfall series
selected from 13 rainstorms in 2008 and 2011 within the region. For regional
rainfall frequency analysis, the well-known L-moments approach and related
criteria were used to examine extremely climatic homogeneity of the region.
According to the L-moments approach, Generalized Pareto distribution was
recognized as the regional frequency distribution. The synthetic rainfall
series were fed into the PANTA RHEI model. The simulated results from PANTA
RHEI were provided to a 2-D hydrodynamic model (MEADFLOW), and various
simulations were performed. Results from the integrated modelling framework
are used in the ongoing study to regionalize and map the spatial distribution
of flash flood hazards with four levels of flood severities. As an overall
outcome, the presented framework can be applied in areas with inadequate
runoff records. |
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| ISSN: | 2199-8981 2199-899X |