Wiki wasn’t helpful: didn’t even tell me if any of the old Roman aqueducts were still in use to bring water to Rome.
So, what aqueduct still in use today is the oldest? Are any Roman aqueducts from the Republic or Empire still in use to bring water to Rome? What is this water used for?
I don’t think any of the aqueducts going into Rome itself have been functional in many, many centuries. The things relied on gravity to flow the water, so they had a gradual downward slope. This required them to be long elevated “bridges” extending over many miles. It’s a lot to expect such complex structures to hold for for 2,000 years or so. There are numerous breaks in the ones I’ve sen outside Rome.
Actually, the arched “bridges” of ancient aqueducts constituted a small percentage of an aqueduct’s overall length. The prohibitive cost of constructing such long “bridges” limited their use. Instead, an aqueduct’s line would be mapped out to utilize the terrain and would descent slowly from its source underground to its destination. Most of Rome’s aqueducts only appeared above ground within a few kilometers or less from the city itself. Rome’s first aqueduct, the Aqua Appia was built nearly entirely underground. (An obvious reason to built them underground was to minimize the ability of invaders from locating and destroying your water source. The mighty Aqua Marcia - which was Rome’s first aqueduct to travel extensively on an elevated arched arcade - was only built after Rome had subdued its nearby belligerents, the Samnites.)
To the OP, several of the aqueducts ran well into modern times. Yes, they periodically fell into disrepair, but they’d be eventually overhauled by leading Roman citizens, Pope’s, or even early the Byzantium Administration. For much of its history Rome has relied upon its aqueduct’s for its water supply. Wikipedia states that the Aqua Marcia still provides water to Rome. I believe some other of the aqueducts, or at least their legacy (eg. their source), provide water for modern Rome.
For an excellent introduction to aqueducts consult Trevor Hodge. He is easy to read and makes ancient aqueducts interesting. Also, for a historical overview of the aqueducts in post-Roman times see: Roberts Coates-Stephens’ “The Walls and Aqueducts of Rome in the Early Middle Ages” in the Journal of Roman Studies. Or go right to the source and read Frontinus.
Indeed - but some have held on reasonably well. The Pont du Gard is in remarkable shape for its age - it looks as if it could be made serviceable with about a month’s work.