A new salt tide wave that reached Shanghai Tuesday morning is expected to last a week, but local authorities said it is not likely to have much impact on water supply for the city of 17 million people.

 

The tide, the third since the beginning of summer, arrived at the mouth of the Yangtze River near Shanghai at about 2 a.m. Tuesday, said Sheng Daisun, director of the Yangtze River Raw Water Plant.

 

Local water authorities, who are closely observing the development of the salt tide, had already stored sufficient water in the city's reservoirs, he said.

 

The salt tide normally takes place at the mouth of the Yangtze River each winter or early spring. The river flow rate decreases, causing the chloride level to rise and sometimes exceed national limits.

 

An exceptional drought this year led to low water levels in the upper reaches of the Yangtze River. As a result, salt tides have been occurring two months earlier than in previous years.

 

The first salt tide hit Shanghai on Sept. 11 and lasted five days, causing no trouble to the city's water supply.

 

The second wave lasted nine days in Shanghai starting Oct. 9, and affected normal water supply in a few districts.

 

(Xinhua News Agency October 25, 2006)