Research On Hydrological Effect Of The YiluoHe Catchment's Land Cover Change

The change of land use and cover is one of the most important influences which the terrestrial ecosystem and global environmental change act on the global climatologic change and mans activity. During the decades and even a century, mans activity causing the environmental change is more and more visible than the natural factors, and becomes the main factor gradually. The change of land use and cover alters the surface evaporation, the status of the soil humidity and the retention quality of land cover, so that it changes the volume and the process of the catchment's flood. It plays an important role in the course of catchment's flood and water balance. So the influence of the change of the land use and cover impacting on the hydrological dynamic change has already become the hot point all around the global hydrological researching.The article is summarizing the development of drainage area of distributed physical model, summing-up the development of the Green-Ampt Model, the ways of studying the hydrological effect on the change of the land use and cover and its studying result.According to the natural environment in YiluoHe Catchment, by using the remote sensing image, we extract the land using status of Lushi and Luanchuan sub-catchments in 1980, 1990 and 2000, analyzing the changing of the land use and cover. Through the long sequence statistics method, we construe how the hydrological factors, which is including the annual evaporation capacity, precipitation, runoff and sediment yield and the characteristics of the flood, respond the forest cover change. And we also compare and analyze the change of land use and cover between the Lushi and Luanchuan sub-catchments. Then we speculate and estimate the notable offending point which the change of land use and cover acts on the catchment's hydrological sequence.We get the catchment's characteristic information in the area of Lushi and Luanchuan by using the ways called complex information extracting, which is combining information of DEM and the main river-way of the real river. We construct the distributed physical Model, which is considered the land cover. The model is simulated the eighteen typical floods in the Luanchuan Catchment since 80's and we obtain good results. It proves that this kind model could recurrence the flood in Luanchuan.I only take Luanchuan Catchment as my studying object and analyze the dependency relation between the influence factor and the runoff. I constitute three land cover scenarios by using the historical inverse technique. According to the simulative method of catchmen's hydrology, I simulate the floods by using the distributed physical Model, and study the hydrological effect which is caused by the change of land cover. What the most important thing I study in this area is the influence regulation that the change of land cover acts on the flood peak and the flood volume, meanwhile, comparing and analyzing the regulation that the different kinds and different volume of floods act on the change of forest cover.