Is there any kind of inexpensive light tubes for the generation of electricity?

A question from Luis Ferrira-

I am retired and living on my own in a little farm limited by a rivulet that in ancient times was used to fuel a mill. In Winter an almost constant amount of water, that can fill a tube of 6 inches, drops vertically from a height of 2.6 meters.

I was told that in some parts of the world, namely where rice fields are placed on different levels, people use some kind of inexpensive light tubes with a turbine at the end for the generation of electricity. My question is: if this is true, where can I find the gear?

Thank you for your service!