How Did Roman Aqueducts Work?: The Most Impressive Achievement of Ancient Rome’s Infrastructure, Explained

At its peak, ancient Rome enjoyed a vari­ety of com­forts that, once lost, would take cen­turies to recov­er. This process, of course, con­sti­tutes much of the sto­ry of West­ern civ­i­liza­tion. Though some knowl­edge did­n’t sur­vive in any use­ful form, some of it remained last­ing­ly embod­ied. The mighty ruins of Roman aque­ducts, for exam­ple, con­tin­ued to stand all across the for­mer Empire. Togeth­er they once con­sti­tut­ed a vast water-deliv­ery sys­tem, one of whose con­struc­tion and oper­a­tion it took human­i­ty quite some time to regain a func­tion­al under­stand­ing. Today, you can learn about both in the video from ancient-his­to­ry Youtu­ber Gar­rett Ryan just above.

“Greek engi­neers began build­ing aque­ducts as ear­ly as the sixth cen­tu­ry BC,” says Ryan. “A stone-line chan­nel car­ried spring water to archa­ic Athens, and Samos was served by an aque­duct that plunged through a tun­nel more than one kilo­me­ter long.”

These sys­tems devel­oped through­out the Hel­lenis­tic era, and their Roman suc­ces­sors made use of “arch­es and hydraulic con­crete, but above all it was the sheer num­ber and scale that set them apart.” Most Roman cities had “net­works of wells and cis­terns” to sup­ply drink­ing water; aque­ducts, in large part, came as “lux­u­ries, designed to sup­ply baths, ornate foun­tains, and the hous­es of the élite.” Man’s taste for lux­u­ry has inspired no few of his great works.

The task of build­ing Rome’s aque­ducts was, in essence, the task of build­ing “an arti­fi­cial riv­er flow­ing down­hill from source to city” — over great dis­tances using no pow­er but grav­i­ty, and thus on a descend­ing slope of about five to ten feet per mile. This pre­ci­sion engi­neer­ing was made pos­si­ble by the use of tools like the diop­tra and choro­bates, as well as an enor­mous amount of man­pow­er. Roman aque­ducts ran most­ly under­ground, but more impres­sive­ly in the ele­vat­ed chan­nels that have become land­marks today. “The most spec­tac­u­lar exam­ple is undoubt­ed­ly the Pont du Gard, locat­ed just out­side Nîmes,” says Ryan, and TV trav­el­er Rick Steves vis­its it in the clip above. What once served as infra­struc­ture for the well-watered man­sions of the wealthy and con­nect­ed now makes for a fine pic­nick­ing spot.

Relat­ed con­tent:

Roman Archi­tec­ture: A Free Online Course from Yale Uni­ver­si­ty

A Vir­tu­al Tour of Ancient Rome, Cir­ca 320 CE: Explore Stun­ning Recre­ations of The Forum, Colos­se­um and Oth­er Mon­u­ments

A Huge Scale Mod­el Show­ing Ancient Rome at Its Archi­tec­tur­al Peak (Built Between 1933 and 1937)

The Roads of Ancient Rome Visu­al­ized in the Style of Mod­ern Sub­way Maps

How Did the Romans Make Con­crete That Lasts Longer Than Mod­ern Con­crete? The Mys­tery Final­ly Solved

Every­thing You Want­ed to Know About the L.A. Aque­duct That Made Roman Polanski’s Chi­na­town Famous: A New UCLA Archive

Based in Seoul, Col­in Mar­shall writes and broad­casts on cities, lan­guage, and cul­ture. His projects include the Sub­stack newslet­ter Books on Cities, the book The State­less City: a Walk through 21st-Cen­tu­ry Los Ange­les and the video series The City in Cin­e­ma. Fol­low him on Twit­ter at @colinmarshall or on Face­book.