The brilliant invention of a Spanish emperor to prevent floods in the Roman Empire

The architect of this nightmare was the aforementioned Tiber, a river with a shocking extension – the third longest in the Italian peninsula – which watered the seven hills that saw the birth of the Eternal City. Flowing and regular, in principle at least, it favored commercial activity, nourished crops and gave water to beasts and men. However, he also had a “soul of his own” that made him indomitable. This is what, at least, Professor of Classics and Letters Kyle Harper states in his extensive essay ‘The fatal fate of Rome. Climate change and disease at the end of an empire‘: “Despite the ingenious efforts of the Romans to control it, sometimes the river jumped the bank and flooded the city.”

Life and death

Harper maintains that the Tiber floods are recorded irregularly in classical sources, but he maintains that the majority of authors confirm their danger due to the topographic conditions of the Eternal City. And its location on the banks of the river made it the perfect target for floods. In his book ‘Histories’, the chronicler Paulo Orosius (born in the 4th AD) documented that, during the consulship of Quintus Lutatius Catulus (back in the 3rd century BC), “the river, swollen by unusual rains and overflowed for a longer time and “With more water than could be expected, it destroyed all the Roman buildings that were on the plain.” In his words, “different places coincided in the same misfortune,” with dozens of homes destroyed.

It was not the only thing to see that the water generated chaos. The politician and historian of the 1st century AD Cornelius Tacitus pointed out that the floods of the Tiber destroyed the Sublicius bridge, the oldest in the Eternal City, and that they generated atrocious fear among the population in 60 BC «The sudden overflow of the river , its flow growing disproportionately, flooded everything as it overwhelmed the obstacle that stood in the way of its fury. “Not only the flattest parts of the city, but flooding even the places considered safest.” The current “carried away many people who were in public places” and “surprised many in their workshops, tabucks, and even in their own beds.”

That madness brought about “hunger in the town, the ruin of commerce and a shortage of food.” And added to this was the destruction of countless homes. “The foundations of the buildings were undermined by the action of stagnant waters, and they collapsed when the waters of the river receded,” the same man added. Tacit. The flood, like the rest, was considered a bad omen; a kind of curse forged in the heat, or so they believed at the time, of a terrible political decision that had angered the gods. Cassius Dion himself, for example, attributed one of the floods to Aulus Gabinius’ decision to restore Ptolemy XII to the throne of Egypt.

The imperial era did not escape the floods. In the 1st century AD, the second emperor of Rome, Tiberius, suffered one of the largest floods of the time during his reign. According to Dio Cassiuswhen the river “flooded a large part of the city, making it navigable,” the boss ordered “five senators, chosen by lot, to establish permanent surveillance so that its flow would not be excessive in winter or scarce in summer, but rather “It will always, and to the extent possible, flow with a stable flow.” We do not know whether or not this measure alleviated the problems generated by the liquid element. What we do know is that years later, in 69 and 101 AD, floods occurred again.

Fight against water

The floods were a true nightmare for Rome. To such an extent that the different emperors mobilized their legions of engineers and scholars to avoid them. The clearest example was Trajan. The Hispanic, born in our traditional Itálica, was an advance of naval construction. To begin with, he ordered the construction of a second hexagonal port in the year 100, southeast of that of Claudius. As explained by the professor of Ancient History Santiago Montero in ‘Hydraulic Engineering and Religion in the Roman Empire’, the work was completed with various warehouses, two kilometers of docks and river facilities in the Eternal City intended to store the goods that arrived through the Mediterranean.

The zenith of the project was the excavation of an artificial canal next to this new port with a double purpose: to facilitate navigation to the Tiber and to prevent the river from flooding. «She was the famous Fossa Traianaknown today as the Fiumicino canalwhich connected the Tiber with the sea. The objective of the pit, whose bottom was tiled to allow it to be raked and the mobilization of alluvium, was, among other things, for the new mouth to facilitate the drainage of floodwaters and prevent flooding of Rome,” adds the expert. An inscription from the time found in Ostia corroborates this:

“The emperor Caesar Nerva Trajan Augustus Germanicus Dacicus, son of the divine Nerva, invested with tribunician power (…) built this ditch to prevent the floods of the Tiber that frequently attacked the city, having established a permanent water channel.”

The Fossa Traiana was not only a brilliant idea from an engineering point of view. Furthermore, it represented an evolution of the imperial mentality. Montero believes that, until the arrival of Trajan, the emperors associated the flooding of the Tiber with a bad omen. However, the Hispanic “rejected the entire religious meaning” of the increase in flow and understood that it corresponded to a natural problem that hydraulic engineering could overcome. This maxim is based on the enormous number of canals and similar works that he created throughout the entire country. Empire. Some buildings that, despite their great economic cost, also earned him great popularity.

There is no doubt that the new canal alleviated the flooding of the Tiber. At least, in part. However, in 103 AD the flow overflowed again. “Pliny the Younger described a flood in the kingdom of Trajan that, despite the spillway built by the emperor, swept away the furniture of the aristocracy and the tools of the peasantry through the streets of Rome,” explains Harper, in this case. This is how Pliny wrote: «The Tiber has left its channel and at the points where the banks are lowest it has deeply damaged the land. Despite the drainage of the canal that the most provident emperor has had dug, it covers the valleys, floods the fields and places where the land is flat and is visible instead of the ground. You don’t always win.