| Title: | Improvement of the SWAT model for event-based flood simulation on a sub-daily timescale |
| Authors: | Yu, D., P. Xie, X. Dong, X. Hu, J. Liu, Y. Li, T. Peng, H. Ma, K. Wang and S. Xu |
| Year: | 2018 |
| Journal: | Hydrology and Earth System Sciences |
| Volume (Issue): | 22(9) |
| Pages: | 5001-5019 |
| Article ID: | |
| DOI: | 10.5194/hess-22-5001-2018 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic only |
| Primary Application Category: | flood impacts or conveyances |
| Secondary Application Category: | sub-daily hydrologic and/or pollutant processes |
| Watershed Description: | 30,630 km^2 Wangjiaba river, a tributary of the Huaihe River located in east central China. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | Flooding represents one of the most severe natural
disasters threatening the development of human society.
A model that is capable of predicting the hydrological
responses in watershed with management practices during
flood period would be a crucial tool for pre-assessment of
flood reduction measures. The Soil and Water Assessment
Tool (SWAT) is a semi-distributed hydrological model that
is well capable of runoff and water quality modeling under
changed scenarios. The original SWAT model is a long-term
yield model. However, a daily simulation time step and a
continuous time marching limit the application of the SWAT
model for detailed, event-based flood simulation. In addition,
SWAT uses a basin level parameter that is fixed for the
whole catchment to parameterize the unit hydrograph (UH),
thereby ignoring the spatial heterogeneity among the subbasins
when adjusting the shape of the UHs. This paper developed
a method to perform event-based flood simulation
on a sub-daily timescale based on SWAT2005 and simultaneously
improved the UH method used in the original SWAT
model. First, model programs for surface runoff and water
routing were modified to a sub-daily timescale. Subsequently,
the entire loop structure was broken into discrete
flood events in order to obtain a SWAT-EVENT model in
which antecedent soil moisture and antecedent reach storage
could be obtained from daily simulations of the original
SWAT model. Finally, the original lumped UH parameter
was refined into a set of distributed ones to reflect the spatial
variability of the studied area. The modified SWAT-EVENT
model was used in the Wangjiaba catchment located in the
upper reaches of the Huaihe River in China. Daily calibration
and validation procedures were first performed for the
SWAT model with long-term flow data from 1990 to 2010,
after which sub-daily (1t D 2h) calibration and validation
in the SWAT-EVENT model were conducted with 24 flood
events originating primarily during the flood seasons within
the same time span. Daily simulation results demonstrated
that the SWAT model could yield very good performances in
reproducing streamflow for both whole year and flood period.
Event-based flood simulation results simulated by the subdaily
SWAT-EVENT model indicated reliable performances,
with ENS values varying from 0.67 to 0.95. The SWATEVENT
model, compared to the SWAT model, particularly
improved the simulation accuracies of the flood peaks. Furthermore,
the SWAT-EVENT model results of the two UH
parameterization methods indicated that the use of the distributed
parameters resulted in a more reasonable UH characterization
and better model fit compared to the lumped UH
parameter. |
| Language: | English |
| Keywords: | |