The most serious salt tide to strike the Pearl River estuary, south China, since last winter is losing intensity as a result of increased rainfall along the river's valley in late February.

The Guangdong Provincial Astronomers Society monitored no salt tide in Xiaoying Watergate near the Hengmen Waterway in the estuary of the Pearl River, which empties into the South China Sea, from February 28 through to Sunday, a record for the length of time without salt tide since last autumn.

The maximum salinity monitored at the Dayongkou Watergate near the Modaomen Waterway, also in the estuary, last Friday was 290 grams per liter, a record low since last autumn. The chlorine content monitored at the same site stayed above 5,080 grams per liter from February 17-28.

The Pearl River estuary fell victim to repeated rounds of salt tide as a result of reduced rainfall in autumn, winter and spring, caused by abnormal weather in south China, especially Guangdong Province, in recent years.

The salt tide 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.

However, two rounds of massive rainfall in the drainage area of the Pearl River on February 18 and February 27 led to rapid increases in the water level of Xijiang, Beijiang and Dongjiang, all tributaries of the Pearl River.

The increased rainfall played an important role in washing away salinity in the water of the Pearl River, said a specialist with the Guangdong Provincial Astronomers Society, who predicted that the salt tide would be on the decline in March, though it might re-appear later on. 

(Xinhua News Agency March 6, 2006)