Author(s): Nmns Bandara Nawarathna; Tianqi Ao; So Kazama; Masaki Sawamoto; Kuniyoshi Takeuchi
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Keywords: Block type topmodel; Muskingum-cunge method; Hydrologic model; Mekong river basin; Land use; Human activities
Abstract: BTOPMC (Block wise use of TOPMODEL with Muskingum-Cunge flow routing method) is a physically based semi-distributed hydrological model that uses Geographical Information System in terrain modelling. The digital stream network is built after removing pits in the original Digital Elevation Model (DEM). Muskingum-Cunge method routes the simulated block wise TOPMODEL runoff to the downstream. The Mekong River basin, one of the largest river basins in Asia has been selected for this research work. The BTOPMC is used to simulate Hydrographs at five stations in the Mekong river basin with the unit time interval being 24hours. Simulations were carried out for four years. Basin physical characteristics such as topography, soil and vegetational activities control the hydrological processes within the watershed. Physically based distributed models have the capability of accounting these properties. Even though the human activities within a watershed play an important role in long-term runoff simulations, distributed runoff models including BTOPMC are still not capable of incorporating human activities such as farming and reservoir operations into the model structure. An attempt has been taken to discuss limitations in model calibration and the applicability of BTOPMC in large-scale watersheds. Differences in observed and simulated runoff provide the useful information of water use within the basin itself. If the human activities within the basin are well defined, BTOPMC is a good tool to model hydrological process in large-scale watersheds.
Year: 2001