Yangtze maritime officials warned on Tuesday 14 September that the water level at Zhicheng in Yichang, immediately downstream of the Three Gorges Dam, had risen by two metres. This was despite the commencement four days earlier of the reservoir storing cycle, which normally causes the water level immediately downstream of the Three Gorges to fall. Shipping lines have been advised to monitor the water level to avoid possible collision.

Within 24 hours of the start of the storing cycle, the water level in the reservoir behind the dam rose by 2.65 metres from 160.2 metres. It is expected to rise to 175 metres for the first time ever by 30 October.

The unexpected water level rise in the middle reaches downstream of the dam was caused by recent heavy rainstorms and a new method of managing the storing process, according to the Yangtze Maritime Authorities.

In a separate development, a waterway survey conducted after the flood season has shown that the problems of silting and debris accumulation are worse than in previous years because of the rainstorms. The storing cycle, which slows down current speed in the reservoir, is exacerbating the silting problem.

Silting represents the greatest challenge for maintaining the waterway in the middle reaches, according to officials from the Yangtze Waterway Bureau. They have identified 15 trouble spots, six of which are top priority. Four dredgers have been deployed and another six are on stand-by.