The Impact of Land Use Change on Hydrological Cycle at a Semiarid Headwater Catchment in North China

To obtain accurately and timely the land-surface changing information is very important for describing the nature and extent of land resources. And the impact of land use changes on the hydrological system behavior of watershed is of major interest to water resources management. Particularly in semi-arid areas, where water resource is strongly shortened, the impact of land use changes on the hydrological cycle is more obvious and more serious. To investigate such effect quantitatively, Land sat TM (1987), ETM data (2001) are used for mapping the land use and land cover changing within the semi-arid Shalamulun River catchment located at the southeast parts of Inner Mongolia of China in this paper. The decision tree method is used to detect the land use classes. And the classification results are compared with the land use classification map of 1996. Based on the observed precipitation and discharge data from 1987 to 2007, the hydrological responses to land use change are analyzed quantitatively by investigating the relationship between land use changes and the runoff. The research results show that the changes of grass land, forest, barren land and crop land area are the most important factors to affect the runoff in this study area.