Drive Factors Of Surface Runoff Changes Between 1980-2010 In The Mountainous Areas Of Haihe Basin

Climate change and human activities cause the change of surface hydrological processes,and the temporal and spatial distribution of surface runoff,therefore have impacts on the regional ecosystems and socio-economic development.Quantitative identifying the characteristics and impact factors of the surface runoff changes are important for the watershed management.This research takes the mountainous areas of Haihe Basin?including Luan River Basin,Beisan River Basin,Yongding River Basin,Daqing River Basin,Zhangwei River Basin and Ziya River Basin?as example,where have frequent human activities and scarce water resources.GIS,RS,hydrological collection,multivariate statistical analysis and other methods are used to analyze the change trend of surface runoff and the impact of climate change and human activities on runoff in the Haihe Basin during 1980-2010.The results are as follows:?1?The surface runoff of Luan River Basin,Beisan River Basin,Yongding River Basin,Daqing River Basin and Zhangwei River Basin show a significant downtrend?p<0.05?from 1980 to 2010 except for Ziya River Basin.At the same time,an abrupt change?p<0.05?point of runoff existed in Luan River Basin,Beisan River Basin,Yongding River Basin and Daqing River Basin around 1998.?2?The rising trend of temperature is significant?p<0.01?in research area from1980 to 2010 and the change rate is 0.03?·a^-1.And the precipitation has no significant change trend.Meanwhile,from 1980 to 2010,the proportion of forest area has increased by 14.56%,the proportion of grassland and farmland has decreased by 10.16%and 5.19%respectively,the vegetation coverage has increased significantly?p<0.05?and the change rate is 0.11%·a^-1.The implementation of ecological restoration projects such as the Three-North Shelter Forest Program and Sandstorm Source Control Project in Beijing and Tianjin convert grassland and farmland to forest and increase the vegetation coverage rate.?3?The population growth is significant?p<0.01?of the research area from 1980 to2010,with an annual increase of 1.167 million;the consumption of domestic and agricultural water has increased significantly?p<0.01?,with an annual increase of 54million m³ and 19 million m³ respectively,which indicate that the demand for water resources in the research area continues to increase.?4?The contribution rate of precipitation changes to surface runoff is 46.70%,the contribution rate of the implement of vegetation restoration project to surface runoff is20.15%.Climate change is the main cause for the decrease of surface runoff in the mountains areas of Haihe Basin.Meanwhile,the impact of extensive vegetation restoration on the surface runoff reduction cannot be ignored.The results reveal the characteristics and main cause of surface runoff changes quantitatively in the mountainous areas of Haihe Basin,which can provide a scientific basis for understanding the cause of the changes in the water resources of the Haihe Basin,balancing the relationship between sand prevention service and water provision service,and strengthening water resources management in the basin.