As the fourth major salt tide invades Shanghai's water regions,
adding more pain to the city's ills from the most severe snowstorm
in years, Shanghai authorities insist that they can handle the
problem without cutting off water supplies.
The mouth of the Yangtze River tends to be hit by salt tides in
winter or early spring, causing chloride levels to rise. The
Shanghai water authority said yesterday the salt tide that hit last
Friday would last two more days, according to China
Daily.
To ensure a steady supply of drinking water, 200,000 tons of
fresh water will be transferred from the Baosteel reservoir near
the Yangtze estuary, said Ouyang Tiaojun, a spokesman for the water
bureau.
A 24-hour monitoring system has also been set up for the upper
reaches of the Yangtze. No water use restrictions are in place at
the moment as the situation is manageable, Ouyang said.
However, The 21st Century Business Herald reported
yesterday that several districts in Shanghai had been widely cut
off from water supplies for several days already, since January
25.
The newspaper said that those residents living on upper levels
of high rises would have special trouble getting adequate
water.
"The water level is as low as it usually is in winter. After the
salt tide hit here on January 25, the reservoir at the mouth of the
Yangtze River couldn’t get adequate water resources. Now the
reservoir is using stored water. But the fact is: the less the
amount of water, the lower the hydraulic pressure. So some
residents living in the upper levels of high rises building may not
be able to get water," The Herald reported, citing an
operator employed by the north Shanghai water supply hotline.
This report was totally refuted today by the water bureau; "The
water supply has never been stopped. Everything is going well. No
such malfunction has occurred due to the salt tide." The bureau
added that to ensure adequate water supplies, they had in place an
effective emergency plan, which was launched when the first tide
arrived.
Shanghai is a frequent victim of salt tide due to the city's
position. Back in 1978, the tide not only invaded the mouth of the
Yangtze River, but also entered the Huangpu River, trapping
Shanghai's Chongming Island for nearly 100 days. When the salt tide
came on October 24, 2006, the Pudong New Area had to cut off one
fourth of its water supply.
Salt tide is a disastrous phenomenon in which the lower course
of a river, with its lower altitude with respect to sea level,
becomes salty when the discharge of the river is low during dry
season.
In recent years, the salt tide threat for Shanghai has become
bigger and bigger. "Because other reservoirs along the Yangtze
River are absorbing river waters, the water volume here has hugely
declined. Moreover, the time gap between salt tides has also
shortened," an anonymous official told?The Herald
yesterday, adding that the snowstorm also has been responsible for
part of the disaster because it caused pipes to freeze, and some
transmission pipes burst, but the situation currently remains under
control.
As for the blizzard, Shanghai's water authorities have already
issued an urgent notice twice on January 28 and January 29,
stressing the significance of keeping the water supply safe and
sound.
Any security incident, if it happens, must be reported to the
authorities as soon as possible – in no more than ninety minutes,
said the notice. The repair teams for all drinking water companies
in Shanghai are standing by on 24 hour alert, and every emergency
will be effectively tackled according to pre-plans, the Shanghai TV
reported.
When current disasters are out of the way, a new initiative will
start. Shanghai's third reservoir will be built on Chongming Island
– the third largest island in China and the largest alluvial island
in the world. The project is?expected?to be completed by
2010. It is expected to somehow ease the salt tide threat for
Shanghai in the future.
(China.org.cn by Zhang Rui, February 1, 2008)
