Waterwheel
The Waterwheel is a 5x5 source of mechanical power from Better With Mods. Unlike the Windmill and Vertical Windmill, the Waterwheel relies on flowing water to generate its power. While this means that it needs to have its blades submerged in flowing water to function, it is unaffected by the weather, allowing it to operate even during rainstorms.
Obtaining
Crafting a waterwheel takes 8 Wooden Blades, which can be made using 4 Siding and 1 Glue or Silky Sludge; as a result, the player needs to already have access to a Windmill.
Due to the substitution option of Silky Sludge for Glue, it is feasible to skip directly from a Windmill to a Waterwheel without ever getting a stoked cauldron to process glue. This video tutorial demonstrates this shortcut:
Usage
To activate a waterwheel, the player must clear out a 5 block long, 5 block high, and 1 block wide area to place it in. Place an Axle down (preferably connecting to a Gearbox) 3 blocks up from the bottom of the cleared area, and place the Waterwheel on this Axle. Then, route a flowing water stream in one direction across any part of the Waterwheel.