Three Gorges Corp, the builder and operator of the Three Gorges Dam and shiplocks, announced at the end of March that it is changing the criterion for a suspension of operation. As of 1 June when the reservoir’s storing cycle starts, shipping will be suspended only when the volume of water entering the reservoir reaches 56,700 cubic metres per second, rather than 45,000 cubic metres as before. The criterion for suspension of operation during the reservoir’s releasing cycle will remain the same at 45,000 cubic metres per second.

This change will add an average of six operational days each year for the shiplocks, giving an increased capacity of 1.5m tons. The initial designed capacity of the shiplocks was 50m tons a year but that level was breached back in 2008. Locks officials believe that engineering measures, improved management and the ongoing vessel standardisation programme should have doubled the capacity to 100m tons by now.

During the first three months of 2011, the total volume of cargo passing the shiplocks reached a record high of 20.62m tons, up nearly 22 per cent over the same period last year.