Application of SWAT in Natural Wetland Catchments. A Case of Rugezi Catchment in Rwanda
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Date
2010
Journal Title
Journal ISSN
Volume Title
Publisher
College of Engineering and Technology, University of Dar es Salaam
Abstract
Hydrologic models are increasingly used to support decisions at various levels and guide water
resources policy formulation, management and regulations. In this study the Soil and Water
Assessment Tool (SWAT) was examined for its applicability in wetland catchment of Rugezi in
Rwanda covering an area of, approximately to, 197 Km2
. The study adopted SWAT model as
recommended by others workers in the region in order to extend its testing. The application of SWAT
model entailed setting up the model using readily available data, sensitivity analysis and calibration. In
this study wetland model physical parameters such as width, depth, length, slope and area were
generated by GIS based SWAT interface. The ground photos available from literature supplemented
and validated the GIS data. An independent simulation was also conducted without implementing the
wetlands in order to study its impacts on the hydrology. Sensitivity analysis indicated that Channel
effective hydraulic conductivity (CH_K2), Surface runoff lag time (Surlag), SCS runoff curve number
under moderate moisture condition (CN2), and Manning’s n value for main channel (Ch_n) are the
most sensitive parameters. Comparable results between simulated and observed streamflows at the
catchment outlet, Rusumo gauging station, were obtained. The Nash and Sutcliffe coefficient values
(CE) and Index of Volumetric Fit (IVF) were 49.15% and 95.6% for calibration and 51.4% and 98.6%
for validation periods, respectively, indicating a satisfactory simulation. It was evident from this study
that the wetland was a major hydrological controlling feature in the basin and should be safeguarded.
These results suggest that SWAT model is potentially useful in studying the hydrology of natural
wetland catchments with limited data. Besides, the authors would like to recommend extensive testing
of the model in other wetland catchments in the region.
Description
Keywords
Hydrology, Modelling, Natural Wetland, Rugezi Catchment, SWAT
Citation
Ndomba, P.M., Magoma, D., Mtalo, F.W. and Nobert, J., 2010. Application of SWAT in Natural Wetland Catchments. A Case of Rugezi Catchment in Rwanda. Nile Basin Water Sci. Eng. J., 3, pp.1-13.