The first cause lies in the natural disasters such as landslides, debris flow etc., which can create some barrier lakes.

The second cause lies in the combined effects of both ancient glacial erosion and moraine accumulation, which can also create barrier lakes (Called as Tsang Haizi in Jiuzhaigou).

The third cause is the calcified mounds that separate water into several small lakes.

All these Haizis share the same characteristic, that is to accept current calcium sediment.