On The Ecological Change Of The Beijing Section Of The Yongding River Basin:From The Republican Period To Present

The YongDing River is the most important river in the Haihe River Basin, providing the material basis for the development of Beijing. Since the Yuan Dynasty, the YongDing River frequently flooded, which had brought huge influence to people’s life and property. During the period of the Republic of China, the YongDing River flooded more frequently than any other historical period. There are several reasons to explain this complicated phenomenon, both natural and human factors, such as precipitation anomalies, war and less repairment. From the 1950s to the 1980s, the disaster of Yongding river were diversification, and human activity had become the main reason for it. Since the establishment of the PRC, conservation project were vigorously constructed in the YongDing River. These projects had played an important role in flood-control, but at the same time they brought a certain effect on the ecological environment of the YongDing River. Many water conservations intercepted a large amount of surface water, so the flow of the river became more and more small, until it finally disappeared, that made its ecological system more fragile. Since the 1990s, goverment changed the concept of the YongDing River, repairing the bank of the river, making greening project of Taihang Mountain, and closing a large number of sand factories. After more than thirty years of governance, the YongDing River put on a green dress and ecosystem gradually restored. From the Republican Period to Present, the ecological system of the YongDing River has experienced a changed from poor to good, this change is very typical.This paper tries to analyze causes and effects of historical changes, this paper aims at providing viable suggestions.