Emperor Qianlong monument for the Emperor Qianlong visit Longchi, was attracted by the beauty here, the imperial pen written "mirror Yang Yun root" five words, meaning the dragon pool 

of water is very clean, the water will be reflected in the blue sky and white clouds, like a side Bright mirror. Longchi water is the mountains down the mountain spring water, so far can see, 

Baiyun and Castle Peak phase, as if the spring is from the roots of the white clouds, so the dragon water, also known as cloud root spring.