Response of runoff to extreme land use change in the permafrost region of northeastern china

Abstract

To study the response of runoff to extreme changes in land use, the Soil and Water Assessment Tool (SWAT) model was used to construct historical, extreme, and future scenarios for several major landscape types in a permafrost region of northeastern China. The results show that the SWAT model is applicable in the Tahe River Basin; forestlands, shrublands, wetlands, and grasslands are the main land-use types in this basin, and the transfers among them from 1980–2015 have impacted runoff by less than 5%. Under extreme land use-change scenarios, the simulated runoff decreased from grasslands, to wetlands, shrublands, and finally, forestlands. The conversion of extreme land-use scenarios produces different hydrological effects. When forestland is converted to grassland, runoff increases by 25.32%, when forestland is converted to wetland, runoff increases by 13.34%, and the conversion of shrubland to forestland reduces runoff by 13.25%. In addition, the sensitivity of runoff to different land-use changes was much greater during flood seasons than in dry seasons. Compared to the reference year of 2015, the annual simulated runoff under the two future land-use scenarios (shrublands to forestlands and shrublands to wetland) was less. Also, both future land-use scenarios showed effects to decrease flooding and increased dryness, This study provided important insight into the integrated management of land use and water resources in the Tahe River Basin and the permafrost region of northeastern China.