Impact of Human Activities on Runoff and Sediment Change of Yanhe River Based on the Similar Precipitation Condition

The impact of human activities on runoff and sediment change is one of the key topics worldwide.Runoff and sediment change is interactively affected by climate change and human activities.The impact of human activities on runoff and sediment change is analyzed based on the similar precipitation condition (SPC) because precipitation is the source of runoff and the power of soil erosion and sediment delivery in the Yanhe River.In the paired-periods with SPC,the depth and process of precipitation are similar.A 50-year data series(1952—2001) of annual precipitation in the basin and runoff and sediment at Ganguyi Hydrology Station of the Yanhe River are analyzed.Results show that there are clear stages of runoff and sediment change influenced by human activities in the SPC.Compared with the period from 1954 to 1963,runoff in annual and flood seasons from 1969 to 1977 is reduced by 18.03% and 32.52%,and sediment,by 47.08% and 47.52%,respectively;from 1981 to 1984,runoff is reduced by 29.77% and 46.29%,respectively,and sediment in both cases,by 73.46%;and from 1988 to 1996,runoff in annual and flood seasons is reduced by 71.72% and 97.79% and sediment,by 162.07% and 161.88%,respectively.