Water diversion from northern Guangdong's Beijiang River to its
western Xijiang River is expected to start in mid-January to
control the severe salt tide, an official with the local water
authority said yesterday.
Fresh water supplies in the southern Chinese province is
currently seriously affected by the tidal phenomenon, caused by
drought, which experts said will last until April.
It has seriously affected the Xijiang River, which is the main
water source for Zhuhai and Macao.
The water authority in Zhuhai is introducing fresh water from
the upper reaches of Xijiang to dilute the salt content before the
Beijiang diversion scheme begins. It follows the end of a powerful
tidal pull, caused by the particular formation of planets.
The tidal pull has increased the salt content in Xijiang, but
with its ebbing, fresh water from the upper reaches of the river
will also flow into the city.
"It is a good time for us to store fresh water to curb the salt
tide," said Chen Zhuhuang, an official with the Zhuhai Water Supply
Company.
Now the fresh water from the river's upper reaches is coming
into the city at about 1,400-1,800 cubic meters per second, higher
than usual.
It is expected that the city will store a total of 20 million
cubic meters of fresh water in the days to come.
At present, the content of chlorine hygronium, the main salt
element, in some water gates in Zhuhai exceeds 4,000 milligrams per
liter, which will be reduced dramatically after the introduction of
fresh water.
The standard content in drinking water is only 250 milligrams
per liter.
Thousands of residents in the city have had to fetch fountain
water and buy bottled water for daily use as the content of
chlorine hygronium in water from taps still remains high at 800
milligrams per liter.
Zhongshan, another city affected by the salt tide, has also
diverted fresh water into Zhuhai.
Residents in Zhuhai and Macao, which draw most of its water from
the Xijiang River, are expected to use drinking water with salt
content to be leveled beneath 800 milligrams per liter within the
upcoming days thanks to the diversions, according to Chen.
"However, the fresh water to be stored can be only used for 20
days, and the city may encounter another more powerful tide pull in
mid-January," Chen said.
"As a result, the water diversion project from Beijiang to
Xijiang is currently urgent."
The city is also waiting for another powerful tidal pull, which
is expected to occur in about 10 days, to introduce more fresh
water from the upper stream of the Xijiang River.
"As the upcoming tidal pull will cause another serious salt
tide, which will increase the salt content in the river, the water
diversion from Beijiang will start as soon as possible," Chen
said.
The Beijiang River, which was heavily polluted by cadmium, a
toxic chemical early in December last year, has returned to a safe
situation.
"The water diversion from Beijiang is only part of short-term
measures, as it will also cause fresh water shortage there," Chen
said.
Another long-term water diversion project from Guizhou Province
and Guangxi Zhuang Autonomous Region neighboring Guangdong in the
west will be completed in 2007.
(China Daily January 5, 2006)