Puhua: the river that runs under the hill

Karst is plumbing. Rain falls on a ridge, sinks through cracks in the limestone, travels sideways along the bedding planes until it finds a way out lower down, and the passage it makes is the cave. At Puhua the stream does this in one visible move: it reaches the foot of a hill and disappears. The name belongs to a community of Zhuoshui township, and the country around it is the country of the Apeng gorge, one of the places Qianjiang lists among its scenery, beside the Guandu, Shengui and Wuli gorges. What a walker sees is a dry valley above and a full channel below, and the sound of water coming out of a place where no water is falling.

Inside, the passage is a corridor with a river in the floor. The roof comes down close to the water in places, then opens into a hall where the beam of a lamp finds nothing at all, and the current keeps the boat against the wall. Stalactites hang where water has entered from the roof and lost its lime on the way down, and flowstone coats the lower walls where water has run for longer. The air is warmer than the valley in winter and cooler in summer, which is the cave's one comfort. The boat is not a ride through a decorated hall. It is the only way to follow a river through a hill.

A cave river is a surveyor of the country above it. Whatever the stream picks up on the surface, soil, leaves and the lime it dissolves, travels through the passage and arrives at the resurgence, so that the colour of the water at the exit is a reading of the weather a day or two earlier. That is also why the caves of this district are large: the rock is soluble, the rain is heavy, and the fall from the ridges to the valley floor is great. Qianjiang's lowest point is 320 metres and its highest 1,938.5, and the water has been using that interval for a long time.