A BTOP model to extend TOPMODEL for distributed hydrological simulation of large basins |
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| Authors: | Kuniyoshi Takeuchi Prasantha Hapuarachchi Maichun Zhou Hiroshi Ishidaira Jun Magome |
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| Institution: | 1. International Centre for Water Hazard and Risk Management (ICHARM), Public Works Research Institute (PWRI), Tsukuba 305‐8516, Japan;2. College of Water Conservancy and Civil Engineering, South China Agricultural University, Wushan, Tianhe, Guangzhou 510642, China;3. Graduate School of Integrated Medicine and Engineering, University of Yamanashi, Kofu 400‐8511, Japan;4. 21st Century Center of Excellence for Research and Education on Integrated River Basin Management in Asian Monsoon Region, University of Yamanashi, Kofu 400‐8511, Japan |
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| Abstract: | Topography is a dominant factor in hillslope hydrology. TOPMODEL, which uses a topographical index derived from a simplified steady state assumption of mass balance and empirical equations of motion over a hillslope, has many advantages in this respect. Its use has been demonstrated in many small basins (catchment areas of the order of 2–500 km2) but not in large basins (catchment areas of the order of 10 000–100 000 km2). The objective of this paper is to introduce the Block‐wise TOPMODEL (BTOP) as an extension of the TOPMODEL concept in a grid based framework for distributed hydrological simulation of large river basins. This extension was made by redefining the topographical index by using an effective contributing area af(a) (0?f(a)?1) per unit grid cell area instead of the upstream catchment area per unit contour length and introducing a concept of mean groundwater travel distance. Further the transmissivity parameter T0 was replaced by a groundwater dischargeability D which can provide a link between hill slope hydrology and macro hydrology. The BTOP model uses all the original TOPMODEL equations in their basic form. The BTOP model has been used as the core hydrological module of an integrated distributed hydrological model YHyM with advanced modules of precipitation, evapotranspiration, flow routing etc. Although the model has been successfully applied to many catchments around the world since 1999, there has not been a comprehensive theoretical basis presented in such applications. In this paper, an attempt is made to address this issue highlighted with an example application using the Mekong basin. Copyright © 2007 John Wiley & Sons, Ltd. |
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| Keywords: | BTOP TOPMODEL effective contributing area groundwater dischargeability mean groundwater travel distance YHyM |
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