When watching films that are set in a time before there was electricity, I would sometimes see public fountains and would idly wonder how they worked. I knew that they had to be driven by gravity, with the water coming from a source like a tower that was higher than the. fountain, the way that many of us still get water nowadays, from city water towers. But how did they fill the water towers in those days?
This article explains.
Ancient Rome received all of its water (according to Encarta, about 38 million gallons a day) through a system of aqueducts. All water flowed to the city by gravity, but because it was arriving from surrounding hills, it could be stored in large cisterns very similar in concept to today’s water towers (the main difference is that cisterns are filled from the top).
Water flowed from the cisterns either through pipes to individual houses or to public distribution points. Fountains served both decorative and functional purposes, since people could bring their buckets to the fountain to collect water. The cisterns provided the height needed to generate water pressure for the fountains to spray. As discussed in How Water Towers Work, a foot of height generates 0.43 pounds per square inch (psi) of water pressure, so a cistern does not have to be that tall to develop enough pressure to give a fountain a reasonable display.
The question that the article does not address is what happens to the water after it comes out of the fountain. It cannot be pumped back up without electricity or having people and animals haul it back up to a height. Did they just let it soak into the ground?
While those old fountains must have been nice to look at, they do seem to be a wasteful use of precious water that had come a long way using aqueducts, themselves a magnificent engineering feat.