A salt tide has hit Shanghai, but has not disrupted the water
supply for the city's 17 million people, according to the local
hydrology monitoring authority.
The salt tide arrived at the mouth of the Yangtze River around
8:00 PM Monday when chloride in the water reached 270 miligrams per
liter, 20 mg higher than the normal level, said Chen Guoguang,
director of Shanghai Monitoring Station under the National Water
Quality Monitoring Network.
The salt tide, the seventh since September last year, is likely
to last another two or three days, said Chen.
The tide would have little impact on the water supply as
sufficient water has been stored in the city's reservoirs, said
Sheng Daisun, director of the Yangtze River Raw Water Plant.
The plant had also increased the number of pumps to ensure a
safe water supply during a major salt tide, added Sheng.
An exceptional drought last year led to low water level in the
upper reaches of the Yangtze River, causing salt tides to occur two
months earlier than in previous years.
The worst salt tide in Shanghai started on Oct. 9 last year when
chloride was almost five times higher than normal. The tide lasted
nine days and affected water supplies in a few districts.
The salt tide usually occurs at the mouth of the Yangtze River
from November to April, when water reserves decrease and seawater
flows in.
(Xinhua News Agency January 10, 2007)