Introduction to Qing'an Dike: Qing'an Dike is located at the intersection of Longgou River and Longchuan River. It was built in the late Ming Dynasty and completed during the Daoguang period of the Qing Dynasty. The South Embankment is 362.5 meters long, 10 meters high, and 6-7.4 meters wide. The North Embankment is 98.4 meters long, 5 meters high, and 4 meters wide. It is a dam built of red sandstone and the first dam in history mainly used to prevent mudslides. protection projects. Some experts believe that the Heijing Qing'an Embankment is an ancient water conservancy project second only to Dujiangyan.