Chengdu to Dujiangyan Irrigation Project and back

If time suits, you can get off at Lidui Park (Li Dui Gongyuan) Railway Station. Upon arrival, just walk to the scenic site: exit from railway station- turn left to enter the ancient city- keep walking to the end of the road and you'll be there.

If getting off at Dujiangyan, you can then take city bus 31 or 101a to the attraction site. The bus departs very frequently, no worrry. But the duration is about 50 minutes.