Introduction to Huayuan Ditch: Huayuan Ditch runs northeast and southwest. It starts from the west side of Taipingding in the northeast, flows through Mapenggou and Hongwan and flows into Huangshiya Reservoir. It is 9 kilometers long and is the longest river in Culai Mountain. The ditch drops from an altitude of 1,000 meters to more than 100 meters. The drop is huge, the bends are many, and the distance is the longest, making it the longest in Cuulai Mountain. There are towering stone walls on both sides of the ditch, dense trees, and mountain flowers everywhere, so it is named Huayuan ditch.