Shanghai defenses against broken dyke ( 2003-07-03 06:42) (China Daily)
A dyke by the Huangpu River broke and caused
localized flooding Wednesday in a second day of drama for city authorities.
The broken
dyke[newsphoto.com.cn]
On Tuesday morning, a
building on Zhongshan South Street near the Huangpu River collapsed due to earth
subsidence blamed on work on nearby cross-river rail tunnels.
Loose sand reportedly poured into the tunnels being built 20 metres
underground.
The dyke, about 100 metres from the collapsed building, began slowly sinking
on Tuesday night, according to Su Ping, an official from the drainage facility
department under Shanghai Water Authority.
The wall cracked in the small hours of Wednesday because of the combined
effects of subsidence and the rising night tide, according to Su.
A site visit Wednesday afternoon found that a pool of water had formed,
extending from the cracked wall almost to the collapsed building site. Several
other structures had also begun tilting and cracks had appeared in nearby roads
as a result of the subsidence.
The city government is closely monitoring the accident and has mobilized all
the relevant departments.
More than 400 police were dispatched to the site, piling up sand bags to form
a wall 4 metres high and 30 metres wide by 5 pm Wednesday as a temporary measure
to contain the Huangpu River.
"My estimation is that the ground around the site sank at least three
metres,'' said an official with the city's anti-flood wall construction
administration.
Sand was also dumped around the fractured wall as a secondary safeguard.
But with Thursday afternoon's tide forecast to reach 4.3 metres, the wall of
sand bags had to be built higher still, officials said.
The city's flood season began on July 1.
Structurally unsound buildings around the site of the collapsed building were
also being demolished yesterday to lighten the load on the sinking ground.
But sources on the rail tunnel construction site said the sand drifts were
almost under control.
Officials yesterday could not estimate how much the damage would cost, but
said it would be difficult to repair, especially since a key drainage pumping
facility had been severely affected.
