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DAM-L LS: Big Projects Targeted for Review (fwd)
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subject: LS: Big Projects Targeted for Review
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Engineering News Record
http://www.enr.com/news/enrpwr37.asp
Big Projects Targeted for Review (9/25/2000 issue)
By John J. Kosowatz in Beijing, with
Debra K. Rubin
International dambuilders were stunned
in 1997 by the
World Bank's brokering of a worldwide $10-million
effort to provide the first "holistic"
review of the
megaprojects. Now, they are bracing for
release of a
report that could rewrite planning and, more
importantly, lending criteria for large
international dam
projects.
Over 300 members of the International
Commission on Large Dams (ICOLD) met last week
in Beijing, China, to formulate a
strategy to smooth
acceptance of large dams, at least 50
meters high. A
succession of speakers referred to the
"critical times"
now facing dambuilders.
IMPACTS. Their focus was on the World Commission on Dams (WCD), whose
report on costs and benefits could redefine methods and practices for
moving large dams into actual construction. The report, to be
released in November, will emphasize socioeconomic and environmental
consequences of large projects-defined not only by governmental
planning agencies, but also by citizen and other activist groups not
traditionally included in planning efforts.
"We will be saying that social and economic impacts are undeniable,"
WCD Commissioner Judy Henderson told ICOLD members. "Indeed, many are
now regarded as unacceptable. But we also say they are not
necessarily inevitable. Given today's knowledge and experience, many
are avoidable."
Topics of particular concern for the industry are resettlement and
compensation for people directly affected by large projects and
environmental impacts upstream and downstream. Many large dams being
built in developing countries have been harshly criticized for
ignoring or paying scant attention to such issues.
"Our concern is that criteria will be so strict so as to prohibit
developing nations from obtaining financing," said ICOLD President
Kaare Høeg, of the Norwegian Geotechnical Institute. That could
severely impact many of the world's planned large dams, particularly
in developing nations. China, Indonesia and Thailand have received
almost 20% of all global aid for hydroelectric projects over the past
20 years, according to London-based WDC India has 18 projects under
construction and another 20 in planning stages.
The issue has forced Høeg to adjust ICOLD's agenda over the past year
to ensure that WCD commissioners and staff are aware of industry best
practices and standards. ICOLD members worry over what they perceive
as an anti-dam bias among WCD staff. Høeg's emphasis in actively
disseminating the organization's papers was meant to counter that
bias. "Ecological balance is a relative term, not an absolute," he
noted.
Henderson says WCD drew heavily on ICOLD research. Its positions on
the environment and socioeconomic impact are progressive and
"frankly, go further than what we can recommend," she says. Henderson
also touched on overruns "associated with downstream impacts that are
often significant...and often unanticipated and thus not compensated
for." And compliance with resettlement policies often is not carried
out.
RALLYING CRY. Resettlement has been a key issue for opponents of
China's $24-billion Three Gorges Dam, the world's largest
construction project. Guo Shuyan, deputy director of the State
Council's Three Gorges Dam Project Construction Committee, said 1.1
million people will be resettled by the time the project is finished
in 2009, at a total cost of $22 billion. That includes funds to build
new housing and infrastructure in relocation areas.
About 125,000 people will be moved out of the area altogether because
of government policy prohibiting development of steep, unfertile
slopes around the Three Gorges reservoir. Chinese designers say Three
Gorges will efficiently pass silt and sediment from the Yangtze River
through a series of outlets at the 90-m elevation of the 181-m-high
dam. But erosion of reservoir slopes could increase the sediment load
enough to cause problems. "Moving 1.1 million people is a most
troublesome task," said Lu You Mei, Three Gorges Development Corp.
president. "It is more difficult to remove people than to build Three
Gorges Dam itself."
DELAYS? Chinese contractors continue to keep to their aggressive
schedule, placing a record-shattering 553,500 cu m of concrete in
one month for the dam's spillway, intakes and powerhouse. But a fatal
accident Sept. 3, the first reported on the project, could affect
some work.
Three Gorges Vice President Wang Jiazhou says an investigation by
Chinese authorities continues into the accident that killed three
workers and injured 30. The accident occurred when workers repairing
a tower-belt crane purchased from Elmhurst, Ill.-based Rotec
Industries dropped some parts from a conveyor. The pieces fell 60 ft,
hitting the workers below.
Rotec Chairman Robert F. Oury terms the accident "devastating," but
declines to elaborate on possible causes while the investigation
continues. He notes, however, that the crane "was under the control"
of Chinese concrete subcontractor Gezhouba. Oury told ENR that the
accident has shut down all six tower-belt cranes at the site, and he
does not know when they would be allowed to restart. He notes they
had been operating incident-free for the last 14 months.
KEEP COOL. Wang reported that two of the project's most perplexing
problems have been solved. A strict quality control program to
consistently produce concrete at a constant 7°C is working.
Aggregate in each of the project's nine batch plants is cooled with
minus 5°C air, and then mixed with ice. A high-speed system of cranes
and conveyors delivers the mix quickly, and cooling pipes installed
in monolithic blocks as large as 1,000 cu m keep heat down during
curing.
At the shiplock, designers and contractors worried over the stability
of the locks' high slopes. Side high wall slopes have a maximum
height of 170 m, excavated from hard rock. The largest locks in the
world, the five-step system has a total length of 1,607 m. A
60-m-wide rock ledge separates the downstream from upstream channel.
Walls are being lined with thin concrete, so engineers were concerned
about stability in excavated bedrock. Wang says the contractor
installed prestressed tendons and high-strength rock bolts to
stabilize the area.
LOOKING AHEAD. The concrete-gravity Three Gorges Dam will eventually
stretch 2,309 m to impound the Yangtze and create a long, thin
reservoir that can store 39.3 billion cu m of water. The project's
size and cost makes it a lightning rod as China pursues an ambitious
plan to build 120 large dams over the next 20 years.
Despite ICOLD's apprehension over the future of large dams, Høeg and
others think they can move forward. He says the commission has
already called for more comprehensive planning and participation by
new constituencies. But neither ICOLD guidelines nor WDC
recommendations are enforceable, and individual governments may
choose to ignore them.
WDC's influence with lending agencies could be a key factor. "You've
got to get the whole package right in terms of social and
environmental factors" said Henderson. "You can take this as a threat
to the way things have been done or as an opportunity to move
forward."
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