The Kaplan turbine is a propeller-type water turbine which has adjustable blades. It was developed in 1913 by the Austrian professor Viktor Kaplan, who combined automatically-adjusted propeller blades with automatically-adjusted wicket gates to achieve efficiency over a wide range of flow and water level.
The Kaplan turbine was an evolution of the Francis turbine. Its invention allowed efficient power production in low-headapplications that was not possible with Francis turbines.
Kaplan turbines are now widely used throughout the world in high-flow, low-head power production.