The Pearl River Delta region is witnessing another major salt
tide due to the combined effects of a tidal pull and a prolonged
drought.
It comes at a time when a diversion project directing water from
Guangdong's northern Beijiang River to the lower reaches of the
Xijiang River is due to be completed soon.
The scheme, which started in mid-January, has already helped
cities along Xijiang River, including Zhuhai and Zhongshan, better
control the worst salt tide that the delta has seen in years.
However, another powerful tidal pull over the course of this
weekend, coupled with the long-term drought in south China's
Guangdong Province, will cause another major salt tide in the area,
sources with the Guangdong Provincial Astronomers Society said.
"The flow of fresh water from the upper reaches of Xijiang River
is continually slowing down, which is another reason for the new
salt tide," Li Jianji, director of the society, told China
Daily on Thursday.
The new salt tide is expected to last until Tuesday, according
to Li.
Water in the Dayongkou in the lower reaches of Xijiang River
will have higher concentrations of salt and chlorine hydronium
because of the tidal phenomenon.
They are expected to reach more than 6,000 milligrams per
liter.
The national standard for chlorine hydronium in drinking water
is only 250 milligrams per liter.
However, the Guangdong water authority said on Thursday that the
new salt tide should not affect water supplies too greatly as it
has been conserving large quantities of fresh water since the start
of the water diversion project.
"Fresh water supplies to Zhuhai, Zhongshan and Macao will be
guaranteed during the upcoming
Spring Festival," said Huang Qingliang, vice-director of the
Guangdong Department of Water Resources.
Sources with the department said that a total of 35
million?cubic meters of fresh water have been diverted to some
small rivers and reservoirs along the lower reaches of Xijiang
River.
Zhuhai, a city that has been severely hit by previous salt
tides, has reserved nearly 16 million?cubic meters of fresh
water.
As a result, the content of chlorine hydronium in drinking water
has reduced from 800 milligrams per liter to 400 milligrams in
Zhuhai.
The salt content of supplies to Macao, which relies mostly on
Zhuhai for its fresh water, has returned to normal levels.
(China Daily January 27, 2006)