Akademik Veri Yönetim Sistemi
2023 SWAT Conference, Arhus, Danimarka, 26 - 30 Haziran 2023, ss.1
Hydrological
models play an important role in the management of water resources. However,
their predictions are inherently prone to multiple sources of uncertainty,
which can significantly impact the accuracy and reliability of model results.
Various methods, such as uncertainty analyses and ensemble modeling are
developed to quantify uncertainty. This paper presents an assessment of
uncertainties in groundwater recharge rates that were simulated using the SWAT
model. This assessment is different from the usual approach taken within the
SWAT-CUP calibration framework and resembles a simplified ensemble modeling
approach. The model is applied to the Fetrek Stream watershed in Izmir (Turkiye),
which is under environmental stress due to excessive groundwater abstraction
and pollution from numerous wastewater discharges. The model includes flow
contributions from 41 point sources and two inflowing tributaries. The watershed
is partitioned into 8 sub-basins and 484 hydrologic response units. Monthly hydrological
fluxes are obtained for a 30-year simulation period. The model is calibrated using
the SUFI-2 algorithm while model performance is evaluated with the Kling-Gupta
Efficiency (KGE), the regression coefficient (R2), and the bias
percentage (PBIAS). Modeled groundwater recharge rates are presented with their
associated prediction uncertainties in the form of uncertainty bands, which
were determined based on an ensemble of model outcomes. Median annual
groundwater recharge rates vary between 160 – 350 mm/yr. The lower and upper
bounds of the estimation uncertainty were on average -13% and +38.7% around the
median rate for the largest sub-basin, respectively. The assessment shows that
the presented approach can be more flexible than the conventional p-factor and
r-factor statistics approach when the number of behavioral solutions is not
sufficient.