Contributions of climate change and human activities to runoff variations in the Poyang Lake Basin of China

Climate change and human activities have impacted the Poyang Lake Basin (PLB) greatly over the past decades, and have significantly changed the local ecological environment and hydrological cycle. Based on the daily records from 16 meteorological stations and 7 gauging stations in the Poyang Lake Basin from 1960 to 2015, the contributions of climate change and human activities to runoff variations under different timescales (annual, flood season, and non-flood season) were explored using the Mann-Kendall, Moving-T test, and a linear regression model. The results showed that on annual timescale, climate change accounted for 91.88% of the increased runoff depth. However, intensive human activities in the subbasins would have reduced the runoff depth in the Poyang Lake Basin. The impact of climate change on the variation of runoff depth increased during the flood season. Climate change and human activities contributed ~57% and ~42%, respectively. Both climate change and human activities could increase the runoff depth during the non-flood season.