Title: | The use of river flow discharge and sediment load for multi-objective calibration of SWAT based on the Bayesion inference |
Authors: | Cheng, Q.-B., X. Chen, J. Wang, Z.-C. Zhang, R.-R. Zhang, Y.-Y. Xie, C. Reinhardt-Imjela and A. Schulte |
Year: | 2018 |
Journal: | Water |
Volume (Issue): | 10(11) |
Pages: | |
Article ID: | 1662 |
DOI: | 10.3390/w10111662 |
URL (non-DOI journals): | |
Model: | SWAT-WB-VSA |
Broad Application Category: | hydrologic only |
Primary Application Category: | calibration, sensitivity, and/or uncertainty analysis |
Secondary Application Category: | hydrologic assessment |
Watershed Description: | 86.7 km^2 Baocun river, located in the eastern part of the Jiaodong Peninsula near the coast in northeast China. |
Calibration Summary: | |
Validation Summary: | |
General Comments: | |
Abstract: | The soil and water assessment tool (SWAT) is widely used to quantify the spatial
and temporal patterns of sediment loads for watershed-scale management of sediment and
nonpoint-source pollutants. However few studies considered the trade-off between flow and sediment
objectives during model calibration processes. This study proposes a new multi-objective calibration
method that incorporates both flow and sediment observed information into a likelihood function
based on the Bayesian inference. For comparison, two likelihood functions, i.e., the Nash–Sutcliffe
efficiency coefficient (NSE) approach that assumes model residuals follow the Gaussian distribution,
and the BC-GED approach that assumes model residuals after Box–Cox transformation (BC) follow
the generalized error distribution (GED), are applied for calibrating the flow and sediment parameters
of SWAT with the water balance model and the variable source area concept (SWAT-WB-VSA) in the
Baocun watershed, Eastern China. Compared with the single-objective method, the multi-objective
approach improves the performance of sediment simulations without significantly impairing the
performance of flow simulations, and reduces the uncertainty of flow parameters, especially flow
concentration parameters. With the NSE approach, SWAT-WB-VSA captures extreme flood events
well, but fails to mimic low values of river discharge and sediment load, possibly because the NSE
approach is an informal likelihood function, and puts greater emphasis on high values. By contrast,
the BC-GED approach approximates a formal likelihood function, and balances consideration of the
high- and low- values. As a result, inferred results of the BC-GED method are more reasonable and
consistent with the field survey results and previous related-studies. This method even discriminates
the nonerodible characteristic of main channels. |
Language: | English |
Keywords: | multi-objective; likelihood function; Nash–Sutcliffe efficiency; BC-GED; SWAT; sediment;
Bayesian inference |