In the 12th Century A.D., the rulers of the city of Hama, Syria, built enormous waterwheels -- norias -- to carry water into the city. These were expanded and enhanced for several centuries:
Each of the wheels can be anything up to 20 meters in diameter (close to 70 feet( and the river water is channelled in to a sluice on the wheel. This flow then forces the wheel to turn and wood boxes raise the water upwards. At the top of the wheel there is an artificial channel in to which the water is discharged.
Using gravity, the water then flows through aqueduct channels to either households or farms in the vicinity. Just as math was used in the construction of the waterwheels so it was in working out the times at which people had access to the water. As a precious commodity it was important that it was shared fairly.
Link via The Presurfer | Photo by Flickr user Ai@ce used under Creative Commons license