Researchers at Oxford University have found that planners and policymakers systematically underestimate the costs and time required to implement large dam projects.
The actual costs of large dams were 96% higher than the estimate, on average, and implementation took 44% longer than scheduled. The new report thus explicitly states that large dams are not economical: "We find that even before accounting for negative impacts on human society and environment, the actual construction costs of large dams are too high to yield a positive return."
via www.enn.com
This covers 245 large dams over 70 years.
Oops.
