Although traditional waterwheels of various types have been used for centuries, they aren't usually suitable for generating electricity. They are heavy, large and turn at low speeds. They require complex gearing to reach speeds to run an electric generator. They also have icing problems in cold climates. Water turbines rotate at higher speeds, are lighter and more compact.
Turbines are more appropriate for electricity generation and are usually more efficient.
Impulse machines use a nozzle at the end of the pipeline that converts the water under pressure into a fast-moving jet. Some lawn sprinklers are reaction turbines. They spin themselves around as a reaction to the action of the water squirting from the nozzles in the arms of the rotor. Examples of reaction turbines are propeller and Francis turbines. In the family of impulse machines, the pelton is used for the lowest flows and highest heads.