Heilongtan Reservoir Introduction: Heilongtan Reservoir was built in 1972 and is an artificial lake. The reservoir is a large reservoir that mainly diverts and stores water from Dujiangyan. It is mainly used for irrigation and also has functions such as flood control, power generation, aquaculture, tourism, and urban water supply. There are 7 gorges, 7 dams and 15 islands in the lake, forming four scenic sections in the north, west, east and middle.