THE HUMAN IMPACTS ON THE RIVER NETWORKS OF THE PEARL RIVER DELTA
论珠江三角洲河网的人为影响

The radial lower reach of either the West River or the North River turned into a single channel because of siltation and reclamation. The southerly extending of the Suijiang river delta had broken the confluence of the West River and North River, and there was only a small stream, Sixianjiao, left to connect the two rivers. Before Tang Dynasty both of the West River and the North River flowed easterly into Guangzhou. However, this situation is being changed by silting of the North River course and scouring of the West River course. The water of the North River is now running westerly to the West River and, therefore, the water from the West River cannot flow into Guangzhou through the small stream, Sixianjiao. The Pearl River Delta, which is composed of that of the West River and the North River, is being changed into an area with small and shallow water networks. Many former river channels in this area have disappeared and the ecological environment is getting worse. Something has to be done for this situation. The key ways to improve this situation and resume the ancient ecological environment are the followings: (1) Drawing water, which is with little sand and pollution, from the West River into the river networks of the Pearl River Delta; (2) Intercepting the North River water to prevent it from running through the West River into Modaomen, one of the 8 estuaries of the Pearl River Delta; (3) Opening all the water gates along the banks of the North River, which were formerly built to avoid the West River water running into the North River, in order to scour the North River course and benefit navigations; (4) Building up new water gates at Sixianjiao to draw water from both of the West River and the North Rivers running easterly.