International Conference on Urban Hydrology for the 21st Century 14-16 October, Kuala Lumpur Comparison of three flood runoff models in the Shonai River basin, Japan

Abstract Distributed parameter runoff models are recently developed and expected to be used in practice. They can take into account spatial distribution of rainfall, land surface conditions and their changes, which affect the runoff from river basins. This paper introduces a grid-cell based distributed rainfall-runoff model that was developed by the authors in 1997. The model uses hydraulics-based overland flow theory and geographic information such as digital elevation models (DEM), land cover/use based on either the National Land Information developed by Geological Survey Institute (GSI) or remote sensing imageries. The objective of this paper is to compare this distributed runoff model with two models conventionally used in Japan: the storage function model and the slope-channel system kinematic wave model. The models are assessed in terms of runoff prediction accuracy in the Shonai River (Shonai-gawa) basin at Shidami (532 km2). This paper discusses some problems to improve the precision of the distributed runoff model and to put it to practical use, by comparing the three models on the basis of the indices for the model parameter sensitivity, such as the difference in peak time, peak discharge and hydrograph shape between observed and simulated hydrographs. The slope-channel system kinematic wave model can reproduce th