Research And Application Of TOPMODEL Considering The Effect Of Water And Soil Conservation Strategies

The effect of vegetation on hydrological processes is seldom considered explicitly in most watershed models, which limits their applicability to evaluate the impacts of water and soil conservation on runoff processes. In this study, a physically-based water and soil conservation strategies-hydrology mechanism was applied to the TOPMODEL Self-distributed Hydrological Models, namely the TOPMODEL water and soil conservation strategies-hydrology model. The water and soil conservation strategies-based model was used to explore the hydrological responses with water and soil conservation strategies in the Xiuhe River basin of Jiangxi Province, red soil area in the south of China.In this research, based on DEM, the methods of extracting basin information are studied and summarized, such as drainage network, river system, flow length. By Arcgis, the individual elevation and soil vegetation type of every grid can be attained through matching the elevation and soil vegetation data with the coordinates.The hydrological responses under variable environment are explicitly taken into account by adding the effect of vegetation on hydrological processes to the flow model of TOPMODEL. Through changing the assumptions of average water conduction of soil in the whole basin as average water conduction of soil in some land cover, inquiring into the flow equation, defining the concept of vegetation-topographic index, the model is developed to reflect the change of land cover with the variation of vegetation-topographic index, and then the runoff-yield is calculated. The Sub-basin Based Isochrone Method is adopted to calculate the runoff-concentration of each sub-basin, then the flow processes of the outlet of each sub-basin is obtained. In the end, with the extraced basin information based on DEM, as well as the "calculate-concentrate-calculate" of the flow processes of the outlet of each sub-basin, the flow processes of the outlet of the whole basin can be attained. In order to verify the feasibility of the TOPMODEL water and soil conservation strategies-hydrology model, this model is applied to the Qingjiang Basin of Xiuhe River. The initial TOPMODEL, Xinanjiang model are used to compare with it. Further, the impacts of several water and soil conservation strategies on runoff processes are calculated as well.Results show that the three models are all applicable to this basin and the TOPMODEL water and soil conservation strategies-hydrology model performs better than the others in simulation accuracy. The water and soil conservation reduce the flood peak and quantity , and contribute a lot to the fiood control and disaster decrease.