The Avis Dam is a dam outside of Windhoek, Namibia. It was built in 1933 by the South African colonial authorities. It first flooded in April 1934, but only exceeded 75% again in 2007.
Wikipedia https://en.wikipedia.org/wiki/Avis_Dam
Friend of Avis Dam official website http://avisdam.org/
Address Namibia
Coordinates -22°34'23.948" N 17°7'49.699" E