论珠江三角洲河网的人为影响

THE HUMAN IMPACTS ON THE RIVER NETWORKS OF THE PEARL RIVER DELTA

文章论述了珠江三角洲河网的发育、演变过程和整治方案。由于人类活动影响 ,珠江三角洲河网区西、北两江下游放射状河系支汊淤断及消亡 ,使西、北两江正干均成为单一水道 ;在两江汇流区内又受绥江三角洲南展而分离开来 ,只留一条狭窄的小河涌 (思贤 )连接 ;由于北江正干的淤积、西江正干刷深 ,使古代 (唐代以前 )西江合北江同流向东流入番禺 (广州 )的形势大变 ,形成江水反向西流入西江 ,西江水不能过入广州。由此 ,西、北两江合成的珠江三角洲主体网河区成为浅水狭窄的小河区 ,以往主要干流多不复存在 ,生态环境日益变劣。因此 ,需要修复河网。关键是把西江大量优质水源 (沙少、污染少 )引回 ,过入珠江三角洲网河区 ,北江水源也需截流使其不再西流入西江 ;开通北江大堤沿途防西水的闸门 (如芦苞、西南、沙口等闸 ) ,以便通水通航 ;在思贤建立新型分水闸 ,可将西。

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.