The Ministry of Transport has approved a plan to start major repair work at the southern shiplocks of the Three Gorges Dam and No.1 shiplock of the Gezhouba Dam at the same time on 7 March, according to Xinhua. The repair work is scheduled to be completed by 26 March at the Three Gorges and 30 April at Gezhouba.

While the work is being done, the northern shiplocks of the Three Gorges Dam, which usually allow vessels to pass upstream, will swap direction at regular intervals so as to allow traffic to pass downstream. At Gezhouba, the No.2 and No.3 shiplocks will continue operation as normal. Priority will be given to vessels carrying livestock, emergency relief materials, containers on shuttle services, ro-ro cargo and long-haul passengers.

This is routine repair activity, but the article did not specify how often such major work is carried out.