Rome was a small village on the Tiber River that grew in power as it conquered other cities. It began as a monarchical Kingdom and then became a Republican nation ruled by elected representatives, one of whom was Julius Ceasar. Rome built amazing road and aqueduct systems to rule its empire, facilitate trade, and deliver water to cities. Rome’s focused on military strength, and it slowly conquered the entire continent of Europe and eventually the Middle East and North Africa.
Figure 15‑28. Roman road in Pompeii. Credit: Paul Vlaar. Used here per CC BY-SA 3.0.
Rome developed an extensive infrastructure, constructing aqueducts to bring water to cities as well as a 50,000-mile road system. Many of the roads still exist today (Figure 15‑28). Along with boats on the Mediterranean, the road network (Figure 15‑29) was a key to maintaining the empire. They could quickly send troops or communicate with administrators in distant locations, and they could engage in trade with distant parts of the empire. Roman roads were not free. Many of them required a toll. As with Sumerian agriculture, the Romans had very precise protocols for road construction. In fact, Roman roads were better than any other roads constructed prior to the 19th century. Local towns were responsible for maintaining their own roads. The Romans constructed roads with different specifications for connections between two cities, intracity roads, and country roads.
One of the most amazing water resource projects in world history was the Roman aqueduct system. Roman canals (aqueducts) followed the contours of hills, tunneled through hills (Figure 15‑30), and spanned rivers (Figure 15‑31). The design principle was to maintain a gentle slope and use gravitational potential energy to drive flow. When a gradual slope was impossible, they moved water down one slope and up the other side in high-pressure lead pipes.
Figure 15‑29. Roman road network in 100 AD. Credit: DS28. Used here per CC BY-SA 4.0.
Figure 15‑30. Tunneled aqueduct section. Credit: Diego Delso. Used here per CC BY-SA 3.0.
Rome supplied its aqueducts from springs and streams. Most of Roman aqueducts were underground waterproof concrete channels with access points spaced along the aqueduct. The aqueduct systems had settling basins, storage tanks, and other advanced hydraulic structures that enabled the aqueducts to function efficiently. The longest aqueduct, the Aqua Claudia, was 42.8 miles long. In 97 AD, 255 miles of aqueducts delivered fresh water to Rome from forest streams coming out of the Appenine Mountains.[1]
As with the Sabeans, the Romans constructed gravity dams to store water, such as the Cornalvo Dam in Spain (Figure 15‑32), which still exists and has been in use for almost 2,000 years.
One of the important uses of water was public sanitation. Romans used approximately 300 gallons per person per day, which is four times higher than typical per capita water use in the United States. They had toilets with water running underneath to carry away the waste. They also had public baths. Nevertheless, Rome was known for its horrible stench.
Figure 15‑31. Pont du Gard aqueduct in southern France built by the Romans. Credit: Benh Lieu Song. Used here per CC BY-SA 3.0.
Figure 15‑32. Cornalvo Dam in Spain. Credit: Charly Morlock. Used here per CC BY-SA 2.0.
The Romans revered agriculture and thought farming was the best lifestyle. One reason that the Romans thought agriculture was such a great occupation was that slaves performed all of the actual work. The Roman farms started out as small family farms in the fifth century BC, but they gradually adopted the Greek farming methods over the next three centuries: large estates with advanced agricultural practices. During the latter part of the Roman Empire, the farms were very productive. Cato described the distribution of labor on a Roman farm of 100 lugera (65 acres): “a foreman, a foreman’s wife, ten laborers, one ox driver, one donkey driver, one man in charge of the willow grove, one swineherd, in all sixteen persons; two oxen, two donkeys for wagon work, one donkey for the millwork.” He also advised the following equipment for winemaking: “three presses fully equipped, storage jars in which five vintages amounting to eight hundred cullei can to stored, twenty storage jars for wine press release, twenty for grain, separate coverings for the jars…”
Bread was the mainstay of the Roman Empire. The Mediterranean region has relatively hot and dry summers and moderate winters; thus, dryland grain farmers in the Roman Empire grew crops in winter. Farmers in the Roman Empire used the two-field system. They grew grain on one field during winter and allowed the other field to lie fallow in order to replenish nutrients in the soil. Some parts of the Roman Empire were more suitable for grain production, and these parts of the empire provided grain for the rest of the empire. Irrigated agriculture in Egypt supplied almost 200 million liters of wheat per year, which was enough wheat for over half of the Roman Empire.
The Romans developed an extensive trade network in order to acquire food and other resources from different parts of the empire. They had hundreds of ships that brought grain from Africa and the Middle East. Four wheeled carts pulled by oxen moved the grain from the farms to the ports. Maintaining sufficient grain was considered a key part of keeping the population pacified. Rome maintained a navy in order to make sure that its grain shipments remained uninterrupted. One of the major needs was to mill the grain, which was accomplished with large water driven mills. They maintained roads within their empire but also constructed roads to engage in trade with those outside the empire (blue lines in Figure 15‑33).
Figure 15‑33. Roman trade network. Credit: Adhavoc. Used here per CC BY-SA 3.0.
[1] Alice Outwater, Water, A Natural History (New York: Basic Books, 1994), p. 134.
Tiber River in Rome. Credit: Rabax63. Used here per CC BY-SA 4.0.