Title: | Analysis of parameter uncertainty in hydrological and sediment modeling using GLUE method: a case study of SWAT model applied to Three Gorges Reservoir Region, China |
Authors: | Shen, Z.Y., L. Chen and T. Chen |
Year: | 2012 |
Journal: | Hydrology and Earth System Sciences |
Volume (Issue): | 16 |
Pages: | 121-132 |
Article ID: | |
DOI: | 10.5194/hess-16-121-2012 |
URL (non-DOI journals): | |
Model: | SWAT |
Broad Application Category: | hydrologic and pollutant |
Primary Application Category: | calibration, sensitivity, and/or uncertainty analysis |
Secondary Application Category: | sediment loss and transport |
Watershed Description: | 4426 km^2 Daning River in central China (in central part of Three Gorges Reservoir Region) |
Calibration Summary: | |
Validation Summary: | |
General Comments: | |
Abstract: | The calibration of hydrologic models is a worldwide
challenge due to the uncertainty involved in the large
number of parameters. The difficulty even increases in a
region with high seasonal variation of precipitation, where
the results exhibit high heteroscedasticity and autocorrelation.
In this study, the Generalized Likelihood Uncertainty
Estimation (GLUE) method was combined with the Soil and
Water Assessment Tool (SWAT) to quantify the parameter
uncertainty of the stream flow and sediment simulation in
the Daning River Watershed of the Three Gorges Reservoir
Region (TGRA), China. Based on this study, only a
few parameters affected the final simulation output significantly.
The results showed that sediment simulation presented
greater uncertainty than stream flow, and uncertainty
was even greater in high precipitation conditions (from May
to September) than during the dry season. The main uncertainty
sources of stream flow came from the catchment process
while a channel process impacts the sediment simulation
greatly. It should be noted that identifiable parameters such
as CANMX, ALPHA BNK, SOL K could be obtained with
an optimal parameter range using calibration method. However,
equifinality was also observed in hydrologic modeling
in TGRA. This study demonstrated that care must be taken
when calibrating the SWAT model with non-identifiable parameters
because these may lead to equifinality of the parameter
values. It was anticipated this study would provide
useful information for hydrology modeling related to policy
development in the Three Gorges Reservoir Region (TGRA)
and other similar areas. |
Language: | English |
Keywords: | |