Xiaonanhai Dam total of 338 freshwater fish species have been identified on the Yangtze. 189 live in the area — currently a preservation — and many of those are found in no other river basin in China. An official study by the Yangtze River Commission in 2003 concluded that the Xiaonanhai dam could not be recommended due to its "unremarkable economic returns". According to "Chongqing Daily", project cost per-kilowatt is triple that compared with other projects along the Yangtze: with total investment estimated at ¥32 billion, the project will cost ¥16,000 per-kilowatt of capacity, whereas the Three Gorges dam, Xiluodu Dam and
Three Gorges Dam St Lawrence Seaway, but half as deep. Before the dam was constructed, the maximum freight capacity at the Three Gorges site was 18.0 million tonnes per year. From 2004 to 2007, a total of 198 million tonnes of freight passed through the locks. The freight capacity of the river increased six times and the cost of shipping was reduced by 25%. The total capacity of the ship locks is expected to reach 100 million tonnes per year. These locks are staircase locks, whereby inner lock gate pairs serve as both the upper gate and lower gate. The gates are the