The waterline is usually measured according to the horizon of Huangpu River, Shanghai. For instance, the present 138-meter water line of the dam of the Three Gorges is not the depth of river, but the height above sea level. At the dam it has risen 66 meters, approximately 60 at the second half of the Xiling Gorge, 40 at the Wu Gorge and 20 at the Wu Gorge. The water line during the dry season is quite different from rainy season because of the influence of climate and rainfall. The water line of the Three Gorges may rise or fall by a few meters, and this will not affect the view of the Eastern Xiling, Wu and Qutang Gorges, in the next couple of years. In the western gorge area the height of the river is about that of the 1998 flood season before the dam. You can see deeper into the ravines, mountain ranges and valleys. The speed of navigating may be slightly affected sometimes, though. Summer time is the slowest going up stream and fastest down stream.

In winter and early spring, the colors of the waters of the “Long River-Great” have the greatest variety. Downriver from the Gezhouba Dam it is emerald. From the Three Gorges Dam, downriver, it is ocean green and upriver from it the Yangtze turns from a murky green to swirls of green and mud to its soil rich color.