| Title: | Multi-step calibration approach for SWAT model using soil moisture and crop yields in a small agricultural catchment |
| Authors: | Musyoka, F.C., P. Strauss, G. Zhao, R. Srinivasan and A. Klik |
| Year: | 2021 |
| Journal: | Water |
| Volume (Issue): | 13(16) |
| Pages: | |
| Article ID: | 2238 |
| DOI: | 10.3390/w13162238 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic only |
| Primary Application Category: | calibration, sensitivity, and/or uncertainty analysis |
| Secondary Application Category: | crop, forest and/or vegetation growth/yield and/or parameters |
| Watershed Description: | 66 ha Hydrological Open Air Laboratory (HOAL) drainage area, located in Petzenkirchen in eastern Austria. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | The quantitative prediction of hydrological components through hydrological models could
serve as a basis for developing better land and water management policies. This study provides a
comprehensive step by step modelling approach for a small agricultural watershed using the SWAT
model. The watershed is situated in Petzenkirchen in the western part of Lower Austria and has
total area of 66 hectares. At present, 87% of the catchment area is arable land, 5% is used as pasture,
6% is forested and 2% is paved. The calibration approach involves a sequential calibration of the
model starting from surface runoff, and groundwater flow, followed by crop yields and then soil
moisture, and finally total streamflow and sediment yields. Calibration and validation are carried
out using the r-package SWATplusR. The impact of each calibration step on sediment yields and total
streamflow is evaluated. The results of this approach are compared with those of the conventional
model calibration approach, where all the parameters governing various hydrological processes are
calibrated simultaneously. Results showed that the model was capable of successfully predicting
surface runoff, groundwater flow, soil profile water content, total streamflow and sediment yields
with Nash-Sutcliffe efficiency (NSE) of greater than 0.75. Crop yields were also well simulated with a
percent bias (PBIAS) ranging from 17% to 14%. Surface runoff calibration had the highest impact on
streamflow output, improving NSE from 0.39 to 0.77. The step-wise calibration approach performed
better for streamflow prediction than the simultaneous calibration approach. The results of this study
show that the step-wise calibration approach is more accurate, and provides a better representation
of different hydrological components and processes than the simultaneous calibration approach. |
| Language: | English |
| Keywords: | SWAT; SWATplusR; soil erosion model; step-wise calibration; HOAL; soil moisture; crop yields; sediment yield; streamflow; sequential calibration |