Large dam projects make bad investments, according to a new global study by a team from Oxford University, England. Three-quarters of the projects analyzed by researchers experienced cost overruns, with the average increase reported as 96% higher in real terms than the figure cited by the project owner when the construction decision was made, says Bent Flyvbjerg, professor of major program management at the university's Saïd Business School.
"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," the study concludes. The report analyzed all large dams built between 1934 and 2007, for which comprehensive documentation was available. It covers 245 projects in 65 countries.