Huotong Irrigation Project is located in Huotong Town, Jiaocheng District. It consists of Longyao Canal, Pipa Cave, etc, and was built in the first year of Emperor Huangtai of the Sui Dynasty (618), presided over the digging project by Imperial Minister of Justice Huang Ju. Longyao Canal, aka Duquan Cave, is situated in Shiqiao Village in Huotong Town. It used to be a combination of 20 meters culvert and hundreds of meters of open canal, but now it became 1,765 meters open canal.