Lake Ruataniwha is an artificial lake in the Mackenzie Basin in the South Island of New Zealand. It was formed in 1977–1981 as part of the Waitaki hydroelectric project. It lies on the traditional boundary of the Canterbury and Otago provinces, with the town of Twizel two kilometres to the north.

The Maadi Cup is the prize for the New Zealand Secondary Schools Boys' Under 18 Rowing Eights. More colloquially, it is the name given to the New Zealand Secondary Schools Rowing Regatta, at which the Maadi Cup is raced. The regatta is the largest school sports event in the Southern Hemisphere, with over 2,087 rowers from 113 secondary schools participating in 2023 The regatta is held annually in late March, alternating between the country's two main rowing venues: Lake Karapiro near Cambridge, and Lake Ruataniwha near Twizel.