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.
PROBLEMS
Three Gorges Dam reported its first fatality, but other
large dams face new scrutiny of costs, impacts.(Photo
by Andy Ryan)
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 projectsdefined not only by governmental planning
agencies, but also by citizen and other activist groups not
traditionally included in planning efforts.
WANG
JIAZHOU
(Photo by Andy Ryan)
"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.
LU
YOU MEI
(Photo by Andy Ryan)
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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