| Title: | Effect of single and multisite calibration techniques on the parameter estimation, performance, and output of a SWAT model of a spatially heterogeneous catchment |
| Authors: | Leta, O.T., A. van Griensven and W. Bauwens |
| Year: | 2017 |
| Journal: | Journal of Hydrologic Engineering |
| Volume (Issue): | 22(3) |
| Pages: | |
| Article ID: | 05016036 |
| DOI: | 10.1061/(ASCE)HE.1943-5584.0001471 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic only |
| Primary Application Category: | calibration, sensitivity, and/or uncertainty analysis |
| Secondary Application Category: | hydrologic assessment |
| Watershed Description: | 1,162 km^2 Zenne River, a tributary of the Scheldt River located in Central Belgium. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | Although the soil and water assessment tool (SWAT) is a physically based hydrologic simulator, it has many parameters
that cannot be measured directly in the field, but must be obtained through a model calibration process. Model calibration is thus an essential
task to obtain the optimal parameter values, which match simulations with observations as closely as possible. This study used the Zenne
River Basin (Belgium) as a case study, which experiences high spatial heterogeneity in terms of geological formation, groundwater recharge,
and rainfall-runoff responses. Therefore, the objectives of this paper were to calibrate the SWAT model on the basis of different calibration
techniques and identify which technique is suitable for such a heterogeneous basin so that the calibrated SWAT can be used as a tool for
integrated management of the Zenne River Basin. Prior to calibration, the sensitive parameters were identified on the basis of a detailed
sensitivity analysis (SA) of the Latin hypercube one-factor-at-a-time (LH-OAT) technique and increased sampling intervals. Then, SWAT
was calibrated by using single-site calibration (SSC) at the watershed outlet; sequential calibration (SC), calibration from upstream to
downstream; and simultaneous multisite calibration (SMSC), where data of two flow gauging stations were simultaneously used in a single
calibration. It was found that at least 200 sampling intervals should be considered for the LH-OAT SA method to obtain converged rankings
of SWAT parameters. In addition, to well capture the spatial variability of heterogeneous catchment and achieve stable sensitivity ranking,
simultaneous multisite SA technique is important. Streamflow findings suggested that the SC and the SMSC techniques provided very good
results and significantly improved model performance, but the SSC results were merely satisfactory. Though the results of SC and SMSC
techniques were similar, the SMSC was selected over SC because it simultaneously handles the entire catchment spatial variability
by assigning different parameter values and allows data information communication among stations in a single calibration. It was thus
concluded that simultaneous multisite calibration should be considered for catchments with a high spatial variability like the Zenne River
Basin. |
| Language: | English |
| Keywords: | Calibration; Multisite; Streamflow; Soil and water assessment tool (SWAT); Zenne River Basin; Belgium |