Medics and firefighters rushed to help the girl, 15, around 7.50pm on Wednesday in Broadbottom, Greater Manchester.
She was pulled from the water but, despite paramedics’ best efforts, she tragically died.
It is understood the tragedy unfolded hours after village’s annual “duck race” event, BBQ and party concluded.
Publicity for the event states online: “The annual duck race and BBQ will be on Wednesday 14 June.
“Race starts at Warhurst Fold Bridge at 6pm and finishes at Weir Cottage, Hodge Lane (No parking available).
“Join us at the finish for the prize giving and BBQ… don’t forget to bring cash for burgers and sausages (with veggie options).”
Greater Manchester Police Detective Superintendent Rebecca Boyce said: “Yesterday evening’s events are nothing short of devastating and my deepest sympathies are with the loved ones of the girl who lost her life in such awful circumstances.
“Officers will continue to support the family during this incredibly difficult time.”