Built in 1909, the earthen dam sat on a site believed by geologists to be a dry lake bed some 300 years old.

The lake went completely dry, and Colorado Parks and Wildlife, in concert with Denver Water resurrected it in 2007.

[citation needed] In 2011, engineers began lowering the water level by two feet due to excess seepage.

[7] In the event, Denver Water began to empty the reservoir in June 2015 for "significant repairs to Antero Dam".

This is because the reservoir is surrounded by even higher terrain on all sides, leading to sinking air when the wind is calm.