Insufficiently stringent management of bid and construction were blamed for costs being US$64M higher than need be, the audit concluded from a sampling of contracts of the major hydro power and flood control scheme. On some small contracts there were no tenders, it found.

However, the project has delivered on, or beat, its principal targets – early flood control and power generation benefits, and shipping efficiency has been better than anticipated, according the to audit report.

In terms of environmental performance, including geology, soil erosion, discharges and pollution, the audit concluded that the project has not exceeded the scope set out in the preliminary design report.

The audit involved more than 150 auditors examining information from the Three Gorges project over six months. Much focus was also given to project and contract management systems, and materials quality, and it was concluded the overall quality of the project was good.