Research On The Effects Of Land Use Change To Runoff In The Basin Of Luo River.

Land Use/Land Cover Change (LUCC) is the hotspot of the global change. As one of the environment effect, the effect on water is the key territory of present research.Luo River district is a mostly semiarid area in middle China. The characteristic of this region is the precipitous, the complicatd surface type, heavy the coefficient of runoff and rainstorms in summer. By accurately estimating regional runoff, it has an important realistic meaning for studying water balance at watershed scale and forecasting rainstorm and flood.In this paper, based on Geographic Information System(GIS), the new ideas and methods of extraction of land use change was explored, according to the RS images of 1980,1990 and 2000 in Luo River district. Moreover, the SCS(soil conservation service) method is used to model the relationship of land use and runoff. The core of the study and conclusions are as follows:1 Characteristics gather depict the land use types from different angles. For the complicated research area, construct the decision-tree to classify by making use of spectrum,shifting and landform characteristics. Finally, the accuracy of classification is able to meet the requirement of practical application. Research shows that the technique can be used to automatic classify of large area with easy handle and objective rules.2 With the land use classification ,the soil texture and the soil antecedent moisture condition, according to the SCS model, calculate the CN value of every pixel. This is a very good amendment to the CN value that getted from traditional method , in a position to better describe the underlying surface. By the SCS model, gain runoff from rainfall based on Kriging interpolation principles. The results indicate that the simulating results are close to the observed data. This method is proved to be feasible and reasonable.3 Runoff is not the reslut of a single surface type, but a wide range combinations of surface types. Because of the different quantity between evaporization and catchdrain , the runoff varies in different land use.