At that time, Toudaogou, the artificial lake in Shengli Park today, was an underground pipeline, which flowed into Renmin Street from the east wall and continued to flow eastward into Yitong River.

Erdaogou-from today's machine tool plant to Clivia Park in the east, it flows into Yitong River near Beishitiao; Sandaogou-near today's North Ring Road.

Later, Toudaogou and Erdaogou evolved into two well-known title deeds. Sandaogou was there at that time, but it should be gone now.

I don't know if it was a man-made project. These three ditches existed before Puyi came to Changchun.