Hydrology and Earth System Sciences
www.hydrol-earth-syst-sci.net
1027-5606
1607-7938
10
6
2006
10.5194/hess-10-829-2006
http://www.hydrol-earth-syst-sci.net/10/829/2006/
http://www.hydrol-earth-syst-sci.net/10/829/2006/hess-10-829-2006.html
http://www.hydrol-earth-syst-sci.net/10/829/2006/hess-10-829-2006.pdf
829
847
2006-11-10
Physically-based modelling of hydrological processes in a tropical headwater catchment (West Africa) – process representation and multi-criteria validation
S. Giertz
sgiertz@uni-bonn.de
B. Diekkrüger
G. Steup
Institute of Geography, University of Bonn, Bonn, Germany
The aim of the study was to test the applicability of a physically-based
model to simulate the hydrological processes in a headwater catchment in
Benin. Field investigations in the catchment have shown that lateral
processes such as surface runoff and interflow are most important.
Therefore, the 1-D SVAT-model SIMULAT was modified to a semi-distributed
hillslope version (SIMULAT-H). Based on a good database, the model was
evaluated in a multi-criteria validation using discharge, discharge
components and soil moisture data. For the validation of discharge, good
results were achieved for dry and wet years. The main differences were
observable in the beginning of the rainy season. A comparison of the
discharge components determined by hydro-chemical measurements with the
simulation revealed that the model simulated the ratio of groundwater fluxes
and fast runoff components correctly. For the validation of the discharge
components of single events, larger differences were observable, which was
partly caused by uncertainties in the precipitation data. The representation
of the soil moisture dynamics by the model was good for the top soil layer.
For deeper soil horizons, which are characterized by higher gravel content,
the differences between simulated and measured soil moisture were larger.
<br><br>
A good agreement of simulation results and field investigations was achieved
for the runoff generation processes. Interflow is the predominant process on
the upper and the middle slopes, while at the bottom of the hillslope
groundwater recharge and – during the rainy season – saturated overland flow
are important processes.
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