“Washing the beach deeply and constructing weirs low” is a famous saying in Dujiangyan water control. Flooding refers to a section of the Feishayan and a section of the Neijiang River that need to be washed deeply. The standard for deep washing is that the ancients prepared deep water at the bottom of the river. The buried "lying iron". The beach should be dug up to the lying iron every year to be just right and to ensure water use in the irrigation area. A low weir means that the Feisha Weir has a certain height, and a high...