| Title: | Comparison of performance of tile drainage routines in SWAT 2009 and 2012 in an extensively tile-drained watershed in the Midwest |
| Authors: | Guo, T., M. Gitau, V. Merwade, J. Arnold, R. Srinivasan, M. Hirschi and B. Engel |
| Year: | 2018 |
| Journal: | Hydrology and Earth System Sciences |
| Volume (Issue): | 22 |
| Pages: | 89-110 |
| Article ID: | |
| DOI: | 10.5194/hess-22-89-2018 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic and pollutant |
| Primary Application Category: | tile drainage effects and/or processes |
| Secondary Application Category: | model and/or data comparison |
| Watershed Description: | 0.03, 0.076, 0.03, 0.023 and 69 km^2 drainage areas, located within the 518 km^2 Little Vermilion River watershed in east central Illinois. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | Subsurface tile drainage systems are widely used
in agricultural watersheds in the Midwestern US and enable
the Midwest area to become highly productive agricultural
lands, but can also create environmental problems, for example
nitrate-N contamination associated with drainage waters.
The Soil and Water Assessment Tool (SWAT) has been
used to model watersheds with tile drainage. SWAT2012
revisions 615 and 645 provide new tile drainage routines.
However, few studies have used these revisions to study tile
drainage impacts at both field and watershed scales. Moreover,
SWAT2012 revision 645 improved the soil moisture
based curve number calculation method, which has not been
fully tested. This study used long-term (1991–2003) field
site and river station data from the Little Vermilion River
(LVR) watershed to evaluate performance of tile drainage
routines in SWAT2009 revision 528 (the old routine) and
SWAT2012 revisions 615 and 645 (the new routine). Both
the old and new routines provided reasonable but unsatisfactory
(NSE <0.5) uncalibrated flow and nitrate loss results
for a mildly sloped watershed with low runoff. The calibrated
monthly tile flow, surface flow, nitrate-N in tile and surface
flow, sediment and annual corn and soybean yield results
from SWAT with the old and new tile drainage routines were
compared with observed values. Generally, the new routine
provided acceptable simulated tile flow (NSE = 0.48–0.65)
and nitrate in tile flow (NSE = 0.48–0.68) for field sites with
random pattern tile and constant tile spacing, while the old
routine simulated tile flow and nitrate in tile flow results for
the field site with constant tile spacing were unacceptable
(NSE = 0.00–0.32 and -0.29–0.06, respectively). The new
modified curve number calculation method in revision 645
(NSE = 0.50–0.81) better simulated surface runoff than revision
615 (NSE = 0.11–0.49). The calibration provided reasonable
parameter sets for the old and new routines in the
LVR watershed, and the validation results showed that the
new routine has the potential to accurately simulate hydrologic
processes in mildly sloped watersheds. |
| Language: | English |
| Keywords: | |