Hydrological responses of a semiarid catchment to land use change in North China: case study the Laohahe River Basin

The Laohahe river with a catchment area of 18, 599 km² located in a semiarid region was selected as a case study to investigate the impacts of land use change on water resources. Land cover maps of 1979, 1989 and 1999 respectively interpreted from remotely sensed images were used to analyze land use change during the last decades. Observed precipitation and discharge data were collected for a period of 1960-1998. Annual runoff and baseflow were selected as important hydrological parameters to indicate the hydrological responses to land use change. The impacts of precipitation on hydrological processes were removed by trend analysis and statistic regression. As a result, the hydrological responses to land use change were analyzed quantitatively by investigating the relationship between land cover change and the hydrological parameters. The results revealed that the change of cropland area including paddyfield area and dry-crop land area mostly affected runoff while the change of paddyfield area mostly influenced baseflow. On the basis of the findings simple linear regression equations between land cover and hydrological components were proposed.