In the Old World
In the Old World, the dam was meant to hold back the lake above, to which it was initially staffed with six people to oversee operations and maintenance. Shelly Guerrera-McKenzie and Laura Vogel were the last human employees there, and they formed their own garage band in their spare time. While their positions were eventually automated, they still left their mark on the place with several datapoints.
In the New World
The dam continued to operate for centuries, keeping the area below from flooding. Once mankind repopulated the world, the land surrounding the dam and overflow basin became occupied by the Banuk tribe, who named the basin "Deep Din".
During the Red Raids, Deep Din was used by the Banuk as a musical instrument to rally their forces in battle. The location was besieged by the Carja for several weeks, eventually resulting in the death of the Banuk's resident drummer. He was succeeded by his daughter, Laulai, who spent her life playing the pipes of Deep Din even after the end of the Red Raids.
When Aloy visited the Cut, she found Deep Din had been flooded, due to the delver Gildun accidentally diverting the flow of water further upriver at the Greycatch. Working together, the two reversed his mistake and drained Deep Din, allowing it to serve as an instrument for the Banuk once again.