The Runoff Changes and Influential Factors Analysis of Wulanmulun River

Abstract

In the past 60 years, climate change and increasingly extensive human activities have greatly altered the runoff in Wulanmulun River basin. Based on the climate and hydrological data in Wangdaohengta station during 1959 - 2015, runoff variation characteristics and the influencing factors were studied. Mann - Kendall trend analysis, statistic analysis, R / S analysis, and double mass curve were used comprehensively in the study. The results indicated that the multi - year change of runoff had a decreased tendency in all, and this trend was the most evident since the end of the twentieth century. The runoff affected by rainfall and human activities appeared three change periods in which the turning years were 1980 and 1995 respectively. The effect of precipitation on runoff decreased, and the influence rate reduced from 18.77% in 1980 - 1995 to 8.48% in 1995 - 2015. The influence of human activities on runoff gradually increased, the influence rate increased from 81.23% in 1980 - 1995 to 91.52% in 1995 - 2015. The Hurst index was 0.3533 for the Wangdaohengta station which indicates that the runoff of Wulanmulun River will have a raise trend in the future.