Impact of Spatial Resolution of DEM on TOPMODEL

With the development of hydrology and water resources, hydrologic model has changed from conceptual hydrologic model into distributed one. Because it is difficult to meet the need for information of distributed model, semi-distributed model has developed quickly in its transition phrase, in which TOPMODEL is a good example. So studies on TOPMODEL's utilities are of great significance with analysis about the dependence of TOPMODEL based on concept of topographic index on DEM spatial resolution. Selecting five sub-basins Xingfeng , Yuecheng , Shengqian , Dongkeng and Lantang in Dongjiang basin, the influence of spatial resolution and basin area on topographic index of TOPMODEL and hydrologic simulation results. It is showed that runoff is dependent on DEM spatial resolution and simulated coefficient of Nash and Sutcliffe gradually reduces as resolution reduces, however, the difference of flow simulation can be compensated by changing hydraulic conductivity. Based on the results of TOPMODEL scale research, analyzing its applications, there are not only theoretical values but also practical values to further apply the model in large-scale basin.