Aqueducts Move Water in the Past and Today

Science Center Objects

An aqueduct has been and continues to be an imporant way to get water from one place to another. Be it 2,000 years ago in ancient Rome, Italy or today in California, aqueducts were and are essential to get water from a place where it exists in ample supply to where it is scarce. Find out how these "ancient marvels" work.

•  Water Science School HOME  •  Surface Water topics  •  Water Use topics  •

Aqueducts move water

If you live in an area where ample rain falls all year, you won't see many aqueducts like the ones pictured here. But there are many areas of the world, such as the western United States, where much less rainfall occurs and it may only occur during certain times of the year. Large cities and communities in the dry areas need lots of water, and nature doesn't always supply it to them.

The California Aqueduct

The California Aqueduct, San Juaquin Valley, California

Some parts of the western U.S. do have ample water supplies, though. So, some states have developed ways of moving water from the place of ample supply to the thirsty areas. Engineers have built aqueducts, or canals, to move water, sometimes many hundreds of miles. Actually, aqueducts aren't a high-tech modern invention—the ancient Romans had aqueducts to bring water from the mountains above Rome, Italy to the city.

Can you see something about the aqueduct picture above that causes some water to be lost in transit? In all environments, but especially In places where the climate is hot and dry, a certain portion of the water flowing in the aqueduct is bound to evaporate. It would be more efficient to cover the aqueduct to stop loss by evaporation, but the cost of covering it must be weighed against the value of the evaporated water.


Aqueducts were popular in ancient Rome

Below is a picture of the Roman aqueduct at Pont du Gard, crossing the Gard River in southern France. The aqueduct was used to supply water to the town on Nimes, which is about 30 miles from the Mediterranean Sea. Although the water ended up in the baths and homes in Nîmes, it originated about 12 miles away in higher elevations to the north. The total length of the aqueduct was about 31 miles, though, considering its winding journey.

There is even a Roman aqueduct that is still functioning and bringing water to some of Rome's fountains. The Acqua Vergine, built in 19 B.C., has been restored several time, but lives on as a functioning aqueduct.

Roman aqueduct at Pont du Gard, France

Roman aqueduct at Pont du Gard, crossing the Gard River in southern France. (Credit: Carole Raddato, Creative Commons)

Aqueducts were not the Roman's choice for water-delivery systems, as they would use buried pipes when possible (much easier to bury a pipe than build an above-ground system). Although aqueducts use gravity to move water, the engineering feats of the Romans are shown in that the vertical drop from the highlands source to Nîmes is only 56 feet. Yet, that was enough to move water over 30 miles. And, if you think you can see the aqueduct in this picture "leaning" to one side, it is a illusion, as the vertical drop is only 1 inch for the 1,500 foot length. It is estimated that the aqueduct supplied the city with around 200,000,000 liters (44,000,000 imperial gallons) of water a day, and water took nearly 27 hours to flow from the source to the city. (Source: Wikipedia)