A. FADIL ET AL.
288
Table 3. Ye ar ly Average simula ted water balance.
Water balance component Calibration
Period (89-97) Validation
Period (98-05)
Precipitation (mm) 392 293
Potential E v apotr anspira-
tion (mm ) 418 427
Actual Evapotrans pirati on
(mm) 273 238
Surface Runoff (mm) 71 41
Soil Water (mm) 71 76
Lateral Flow (mm) 10 7
Base Flow (mm) 45 9
interface were usefully used to calibrate the model.
Hence, the optimal values of the model parameters for
handling water quantities were explicitly specified and
mentioned. The evaluation of the model performance
was carried out successfully with the recommended
statistical coefficients. In this context, the comparison
of observed and simulated flowstream revealed a
Nas h-Sutcliffe coefficient and R² superior to 0.8 for both
calibration and validation periods. These performances
can be enhanced furt hermore using more accura te input
data especially for the soil and temperature features
that were estimated in this study with global data. The
integration of some other climatic data such as solar
radiation, humidity and wind can also improve the ac-
curacy of the evapotranspiration estimation and there-
fore the other water bala nce co mponents.
This study had demonstrated the utility of the remote
sensing and GIS to create combine and generate the
necessary data to set up and run the hydrological mod-
els especially for those distributed and continuous. It
had also showed the ability of SWAT model to be used
to si mulate t he water quantit y in se mi-arid r e gio ns.
Thereafter, the calibrated model can be well used in
Bouregreg watershed to assess and handle other wa-
tershed components such as the analysis of the impacts
of land and climate changes on the water resources as
well as the water quality and the sediment yield.
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