HYDROLOGICAL EFFECT OF URBANIZATION IN YITONG RIVER BASIN

Urbanization is a process of land use change dominated by human beings. The rapid urbanization process has changed the underlying surface conditions and affected the hydrological cycle process of the underlying surface of the basin. Based on the analysis of a long series of hydrological data over the past 35 years, combined with the underlying surface data of satellite images in this area, the hydrological effect caused by rapid urbanization in Yitong River Basin is analyzed. The results show that during the period of 1980-2015, the proportion of unused land represented by wetlands and bare sands decreased from 3.84% to 0.48%, cultivated land decreased from 71.34% to 67.9%, and forest land decreased by 14.9% to 11.7%. Urban land increased from 6.75% to 15.25%, and grassland increased from 0.5% to 1.03. Through the SWAT t model we explore influence of change in the underlying surface on the runoff. The results show that the runoff changes are significant from 1980 to 2000, while the runoff changes from 2000 to 2015 are not obvious. The change of the underlying surface reflects the urbanization of the basin in different periods.and the impact on runoff.