The most serious salt tide will hit the Pearl River estuary in south China on Tuesday because of astronomical factors.
Information from the Guangdong Provincial Astronomers Society said that the salt tide would occur when the moon moves to the nearest position to the earth around 4 AM on Tuesday, and reach a peak when the sun, the moon and the earth are in one straight line about four hours later.
The grip of the salt tide on the Pearl River estuary will start to wane when the sun, the moon and the earth move away from the above-mentioned positions after late Tuesday, said the information.
This round of salt tide in the Pearl River estuary began in mid-February.
The Guangdong Provincial Astronomers Society said that chlorine content monitored at Dayongkou Watergate near Modaomen Waterway in the estuary stayed above 5,130 grams per liter from Feb.17-25, while the salinity observed at Xiaoying Watergate near Hengmen Waterway, also in the estuary, reached 5,500 grams per liter, a record high.
The Pearl River estuary has been a victim of repeated rounds of salt tide as a result of sustained less rainfall in autumn, winter and spring, caused by abnormal weather in south China, especially Guangdong Province, in recent years.
The salt tide has gravely affected supplies of drinking water in the densely populated Pearl River Delta where major cities such as Zhuhai, Zhongshan, Panyu, Dongguan and Shunde are located.
(Xinhua News Agency February 27, 2006)