The dam had been on a U.S. no-strike list but was struck by three bombs anyway. The bombing caused critical equipment to fail and the dam to stop functioning. One of the bombs, a bunker buster, failed to detonate. An emergency ceasefire between the Islamic State, US forces, and the Syrian government, otherwise sworn enemies, enabled engineers to make emergency repairs to the dam to prevent it from failing while the Turkish authorities coordinated to close the gates of dams upstream in order to prevent overtopping. A US drone strike killed three of the civilian emergency dam workers shortly thereafter.

en.wikipedia.org