| Title: | Assessing the model performance of an integrated hydrological and biogeochemical model for discharge and nitrate load predictions |
| Authors: | Pohlert, T., L. Breuer, J. A. Huisman and H.-G. Frede |
| Year: | 2007 |
| Journal: | Hydrology and Earth System Sciences |
| Volume (Issue): | 11(2) |
| Pages: | 997-1011 |
| Article ID: | |
| DOI: | 10.5194/hess-11-997-2007 |
| URL (non-DOI journals): | |
| Model: | SWAT-N |
| Broad Application Category: | hydrologic and pollutant |
| Primary Application Category: | nitrogen cycling/loss and transport |
| Secondary Application Category: | hydrologic assessment |
| Watershed Description: | 692 km^2 Dill River, located in a mountainous area of the State of Hesse (Hessen) in Germany. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | In this study, we evaluate the performance of
the SWAT-N model, a modified version of the widely used
SWAT version, for discharge and nitrate predictions at the
mesoscale Dill catchment (Germany) for a 5-year period.
The underlying question is, whether the model efficiency is
sufficient for scenario analysis of land-use changes on both
water quantity and quality. The Shuffled Complex Evolution
(SCE-UA) algorithm is used to calibrate the model for daily
discharge at the catchments outlet. Model performance is assessed
with a split-sampling as well as a proxy-basin test using
recorded hydrographs of four additional gauges located
within the catchment. The efficiency regarding nitrate load
simulation is assessed without further calibration on a daily,
log-daily, weekly, and monthly basis as compared to observations
derived from an intensive sampling campaign conducted
at the catchments outlet. A new approach is employed
to test the spatial consistency of the model, where simulated
longitudinal profiles of nitrate concentrations were compared
with observed longitudinal profiles. It is concluded that the
model efficiency of SWAT-N is sufficient for the assessment
of scenarios for daily discharge predictions. SWAT-N can be
employed without further calibration for nitrate load simulations
on both a weekly and monthly basis with an acceptable
degree of accuracy. However, the model efficiency for
daily nitrate load is insufficient, which can be attributed to
both data uncertainty (i.e. point-source effluents and actual
farming practise) as well as structural errors. The simulated
longitudinal profiles meet the observations reasonably well,
which suggests that the model is spatially consistent. |
| Language: | English |
| Keywords: | |