Engineering Rome

Engineering the Tiber: A History of Symbolism, Degradation, and Resurrection

By Travis Koblasa Scoccolo

Once regarded in Virgil’s Aeneid as a “sacred bed” of “holy deep” water, the Tiber River, or Tevere in Latin, has now descended from a place in value in Roman society to a neglected wasteland of toxicity and dreariness (Virgil, 19 BC). Originally used as a major resource and natural protection by the Romans close to the city center, the river is now a shadow of disdain for locals and tourists to pass by.

However, the Tiber is not an idle blemish on Rome. Throughout history, Romans have had to cope with its major flooding and the destruction it leaves on the city in its aftermath. In this paper, I will examine the accomplishments and issues associated with how the Tiber has been engineered since Rome’s founding to the present day.

Summary of the Ancient Functions of the River

The First Engineering Accomplishment on the Tiber

Destructive and powerful as it is, Romans have always used the Tiber as helpful mechanism to improve their city. After initially being used as a source of water for irrigation and drinking, the Romans found a more suitable method for the river to meet their hygienic needs. Completed in the 6th century BCE, the Cloaca Maxima is regarded by many as the world’s first major storm water and sewer system. Translated as the ‘greatest sewer,’ it originally was used to transport storm water and empty the marshlands in the city’s forum area before having its open drain covered and converted to a sewer system for waste in the 3rd century BCE (Platner, 2005). Due to this heavy onset of pollution running into the river, aqueducts were then constructed to bring fresh sources of water to Rome beginning with the Aqua Appia in 312 BCE (Platner, 2005).  

Figure 1. Encountering the Cloaca Maxima on the Tiber waterfront.
Figure 2. Centered view of the Cloaca Maxima. Vegetation surround the discharge point as homeless use the covered area for their encampment on top of the ancient monument.

A Strategic Location

Rome’s seven hills are not the only advantage that topography plays in the location of the city. Cicero notes in his In the Republic that the “primary drawback of a coastal location is a city’s vulnerability to surprise attacks,” giving credit to Romulus, Rome’s original founder (Cicero, 2017). By building on the Palatine hill adjacent to the Tiber, the Romans guaranteed themselves the advantages of access to the coast without putting themselves at naval risk of invasion.

The ancient historian Livy also writes on another factor about the favorability of Rome’s location in History saying that the city is “uniquely suited by nature for the expansion,” in a military and cultural sense (Livius, 2006). He claims that the convenient ability to navigate upstream to inland crops provide a “healthy environment” while the city sits at the center of Italy.

Transportation of Materials

In order to support their many monuments, palaces, and temples as well as their bustling populace, the Romans used the Tiber as an important trade route.  Being able to bring marble, travertine, and other building materials from Tivoli and other volcanic districts north of Rome, in addition to resources from seagoing vessels from downstream along the Tiber (Figure 3) made transportation much simpler than carrying the materials on land (Lancaster, 2009). Likewise, the positioning of brickyards and quarries close in proximity to the Tiber decreased transportation costs, easily making the Tiber the most convenient route to bring in materials. And once banked on the Tiber beside Rome it was only a short haul to the historic city center (Figure 4), where most of the well-known Roman structures are (Lancaster, 2009).

Figure 3. An aerial view of the modern port city of Ostia, where in ancient times materials could have been taken from seagoing to river-going vessels upriver along the Tiber to Rome (Boe, 2011).
Figure 4. Section of the river between Trastevere and the city center, most likely in the area where ancient Romans would have delivered supplies to.

Issues Historically and Today

Destructive Flooding

A flood can be described as when high streamflow rises over its riverbanks into the surrounding area as its volume is too great to be contained in its existing area (Aldrete, 2006). Typically before a major flood, Rome receives a period of great rainfall where at first the water is infiltrated by the soil, then leading in to a saturated period where the soil cannot absorb anymore. Once reaching this saturation point, additional water coming onto this soil is considered runoff and is not infiltrated. Soils in the Roman Mediterranean climate that have been baked intensely by the sun can also have impeded infiltration rates, making flooding on the Tiber possible even without soils having reach their saturation point (Aldrete, 2006).

Since its founding Rome has dealt with the Tiber’s major flooding, consequently impacting the low-lying areas around Rome (the Forum is the most prominent example). Although described as being located in such a pristine and strategic location by historians, the city was built in the most flood prone area of the Tiber River on top of a marshland (Aldrete, 2006). Roman flood records on the Tiber stretch from the first in 414 BCE to 398 AD but it is well established that the river has been flooding consistently throughout time and even today (Alessandroni, 1999). For centuries the Romans coped with the flooding as a natural, inherent event that came with living in the capital city.

In Dio’s History, he recounts a major flood in 15 AD that covered most of the city, requiring people “to go around in boats.” Naturally, a flood of this scale interrupts shipping businesses, fishing, material transportation, and generally destroys things located on the ground surface. An early attempt to control the Tiber came from Emperor Tiberius who appointed five senators to maintain a steady flow on the Tiber rather than having “flooding in the winter and drying up in the summer” (Dio, 2018). Their plans ultimately ended with little results to show, however, the idea of controlling the Tiber was something contemplated for millenia.

But Tiberius was not the only figure to try and combat the Tiber. The first known proposal to divert the Tiber came from revolutionary leader Julius Caesar. He planned to divert the river at a point north of Rome and having it flow into the port at Ostia Antica. Previous attempts by ancient Romans suggested creating “better drainage, dikes along the riverbanks, and an actual diversion of the river” (Heiken, 2007). Like Caesar and his plans, most proposals to try to hinder the Tiber’s destruction came into no fruition and the problem remained.

Nearly 1600 years passed before philosopher Andrea Bacci suggested that floodwaters be directed east of Rome along the valley of the Aneine River. But plans like these were only curiosities and dreams for the people in Rome as regimes throughout time failed to enact any significant project to stop the Tiber (Heiken, 2007). We know this because beginning in the 12th century plaques were placed around the city denoting the water level of the Tiber during flood times (Figure 5), which can still be seen scattered in the streets today. Having seen some of these plaques firsthand that remain from centuries ago, I can hardly imagine the destruction they caused to residents and the Roman economy as a whole.

Figure 5. An example of a flood plaque in Rome. This plaque describes the water level of a flood from 1530 under the rule of Pope Clement VII.

Engineering and Controlling the Tiber

After centuries of failing to come up with a better solution to controlling the Tiber’s flooding, the Roman state and its people were finally pushed to the edge. In 1870 the city experienced its most recent great flood, causing catastrophic damage to many parts of the low lying city areas and killing dozens of people. This came around the same time that Italian troops had liberated Rome from Papal rule allied with Napoleon and annexed the city (Calenda, 2013). Using the flood as an attempt to unify the people under the new government, the Ministry of Public Works created a Commission to finally “solve” the Tiber’s flooding problem (Frosini, 1977). The first step was to take survey of the city to measure maximum flood levels on the river and in the affected flooded area. Debates about which permanent solution for controlling the Tiber went on for 6 years until Roman hydraulic engineer Raffaele Canevari proposed that embankment wall heights on either side of the banks would not only be inexpensive compared to shoring and dredging the river, but also the most efficient method (Rankin, 2015). His plan was accepted by the Ministry of Public Works and the control plan thousands of years in the making was finally put into place (Figures 6 & 7).

Construction on the wall began in 1876, being near completed in 1900 when another disastrous flood hit on December 2nd. Despite measuring an astonishing 16.17 meters or 53.05 feet, the walls mostly held and prohibited extensive damage (Frosini, 1977).  For the first time in Roman’s rocky relationship with the Tiber, it seemed like controlling the Tiber was possible. But unfortunately an engineering project of this magnitude does not come without a price. Rankin reveals in the first chapter of Rome Works how the embankment walls caused river ports Porta di Ripetta and Porta di Rapa Grande, as well as the historic Jewish ‘Ghetto’ all to collapse and decay (Rankin, 2015).

Figure 6. Photo of the embankments in 1876 at the time of construction (Ferri, 2012)
Figure 7. A portion of a construction site for the embankment walls, sometime in the late 19th century (Istituto Luce, 2016).

As you can imagine, the project drastically changed the properties on the waterfront, sewers in the lower areas of town, and adjacent streets parallel to the river on either side (Figure 8). As part of his plan, Canevari also included details for a two-way traffic street, called the Luongo Tevere, above each side of the embankment walls. For the sewer overflow in certain areas of town at low elevation, he implemented two sewer headers that would instead collect discharge and aim it downstream away where the river level is significantly lower (Frosini, 1977). And although Canevari’s plan accounted for the new issues that arose from his walls, his direct approach to containing the river radically changed its topography and separated “the city from its river,” leaving the riverbed a forgotten wasteland over four stories below its populace (Rankin, 2015).

Figure 8. The embankment walls as seen from the riverfront walkway.


The Tiber has been consistently polluted ever since the Cloaca Maxima was converted into the city’s main sewer pipeline for waste from public baths and latrines as mentioned before. But in present day, the image of the Tiber is at an all time low. Rome feels disconnected from its ancient river to say the least. Far below the bridges connecting the city are walkways littered with broken bottles, heaps of non-biodegradable trash, and the occasional homeless encampment (Figures 9a & b). On my walk along the Tiber, I found large portions of it overgrown with weeds and vegetation growing out of walls dominated by graffiti and staining from regular flooding. In a city known for its beauty and legacy of its powerful empire, I was surprised to find such a rundown and neglected area so close to the city center.

Figure 9a. A large amount of trash left on the side of the walkway, possibly heaved from above.
Figure 9b. A homeless encampment directly adjacent to the walking path, where shortly afterwards I witnessed a homeless man entering the makeshift brick house in the back.

But the condition of the present Tiber is not due to locals not caring for the riverbank’s aescetics, but falls on the Italian state and its bureaucracy. Elisabetta Povoledo writing for the New York Times describes the “widespread neglect and degeneration” (Figure 10) of the waterfront as a part of “inadequate city administrations.”  Because graffiti taggers and litterers are “almost never fined,” the walkways and riverbanks stay in perpetual disarray as the government cites lack of funds and means to push cleaning efforts back (Povoledo, 2016).

Figure 10. An example of non-biodegradable trash (center bottom) on the Tiber’s riverfront, a common thing seen.

Water Quality

One of my first thoughts when I saw the Tiber is how polluted it must be considering its color. But I was surprised to learn that the Tiber has held this hazy shade of yellowish green for millennia. Originating in the Apennine Mountains, the river spews clear, clean water until reaching an alluvial valley along its path south to Rome. Here, the water encounters yellow silty clay sediment with frequent fine sand layers giving it this unique shade (Marra, 2018).

However, the river is still intensely polluted with trash, heavy metals, and partially untreated sewage, all of which have nothing to do with its color. Many major cities around the globe struggle with pollution and water quality, but for Rome’s relatively smaller size and economic development its problems stick out especially. In 2005, biologists and sanitation specialists contracted by the Roman government conducted a study of the Tiber river quality to determine its effect on overall river quality and organisms in the stretch passing by the Roma Sud sewage treatment plant (Mattei, 2006). They conducted their tests by collecting samples from three different locations: upstream from the sewage treatment plant, at the outfall of the plant, and downstream 600m from the plant.

Using Daphnia magna, a freshwater inhabiting planktonic crustacean, they were able to test the ability of each water sample to support microorganisms, which are essential to every aquatic ecosystem. They measured for “acute toxicity” (which I will call AT for short), being defined as the death rate of Daphnia for a period of 24 hours and 72 hours each. For the first upstream test, the AT rate was 44% immobilization just after 24 hours and 57% for 72 hours. In the sewage outfall sample an astounding 100% AT rate was found just after 24 hours (Figure 11). The downstream sample measured around 0% for its AT rate after 24 hours but jumped to around 30% after 72 hours (Mattei, 2006).

Figure 11. Graph for the acute toxicity results for Daphnia in each of the three test samples (Mattei, 2006).

Besides measuring for the acute toxicity data, the scientists also conducted tests on the Daphnia using the common disinfectant chemicals used to treat sewage discharging into the Tiber. These included sodium hypochlorite, paracetic acid, sodium chlorite, and hydrochloric acid. Putting small quantities of each of these disinfectants respectively into controlled Daphnia habitats all resulted in 100% AT rates (Mattei, 2006).

Their results were eventually published back in 2006, showing us in 2019 that this issue can only have gotten worse. The native Daphnia perishing at such alarming rates inside Tiber test samples is astonishing. It proves to us that the sewage treatment plant is obviously part of the problem but not all of it. The state of the river north of the treatment plant proves that this biological wasteland is in great turmoil. Although not giving insight to predictions for the future, it is safe to assume this issue will not solve itself without human intervention. In urban architect Tom Rankin’s Rome Works, he reveals that treatment of Roman sewage eliminates only about half of its toxic bacteria such as various dioxins and E. Coli (Rankin, 2015). Essentially, the Roman government is constantly dumping disinfectant chemicals into the water along with the toxins it fails to kill.

These works show us that even in our modern age we still fail to prevent human activity from severely impacting our aquatic ecosystems. Cities built around the world on major rivers struggle with this same problem. Keeping this idea in mind we can now look at two similar examples of human impact on rivers with the Danube and the Ganges.

Flood Modeling

Both of the waterways discussed below suffer from industry and human impact, but unlike the Tiber have people who value their river’s conservation and usability. It is my hope that the importance of environmental sustainability moves to Rome, similar to how the concept has with India and East Europe. Although not perfectly executed, projects on the Ganges and Danube should serve as inspirations to Rome that their city’s river can be restored to the great symbol that it was once viewed as.

Before modern computers and technology, Romans gathered hydrologic data on the Tiber using standard measuring tools and daily tracking of the water level. This organized approach started in 1782 when director of the meteorological observatory at the Collegio Romano started extensive record keeping (Aldrete, 2006). The practice became more standardized with the installment of the hydrometer at Ripetta in 1821, which allowed daily measurements of the Tiber during flood times (Aldrete, 2006). This simplistic measuring device can still be seen today and measures several meters tall (Figure 12). Starting in 1921, detailed hydrological data was collected and published from a number of stations around the river basin, helping 20th century researchers understand more about the river’s behavior.

Figure 12. The hydrometer at Via di Repetta.

However, with modern technology engineers can do more than just gather data on water levels and can even simulate its most damaging floods through modeling programs. A 2003 report on a simulation of the great flood of 1870 by Italian researchers is one such example.

The researchers used conservation equations and the hydrograph from the 1870 flood to produce water surface elevation profiles at different points around the city. Then, inserting this data into their modeling software they could determine an estimated peak discharge for the flow of water. By creating a model of the 1870 flood (Figure 13), they were able to better to understand the stage-discharge relationship of the Ripetta gauge in the 19th century and how the flood and travertine embankments built afterward influenced the present layout of the riverbed (Calenda, 2003).

Figure 13. A mesh of the 1870 model hovering over the city center areas (Calenda, 2003).

Modern Conservation of the Tiber

Presently, there are two main categories of groups dedicated to the conservation and cleanliness of the Tiber River basin. This falls between state funded agencies and grassroots non-for-profit organizations that rely on people volunteering.

The two main state funded agencies that oversee the Tiber are the Tiber River Basin Authority (ABT) and the Region of Lazio Authority, who began managing the river basin back in 1989 (Cesari, 2016). They both aim to support the Water Framework Directive, a series of mandates aimed at better flood protection measures dictated by the Italian government in order to understand water flow and supply, as well as waste water treatment and quality.  However, in a report by state authority RCA Giorgio Cesari back in 2016, the organizations have proved to be inefficient in working and coordinating with each other. He notes that there is “still a need for an improved collaboration between different sectors” in order to complete their work in a “harmonized way” (Cesari, 2016). One of the biggest problems he describes is the wastewater spills and overtopping occurring during heavy rainfall in the joint wastewater/storm water sewer systems. Despite regular funding, the organizations have not been able to fix leakages and interruptions in the “very old” water service system. The writer of this report represents the water authority but even he admits that the issue has no easy solution “neither from a technical nor from a financial point of view” (Cesari, 2016). From reading the report, it was clear how widespread problems are in the government authority on the Tiber. Their coordination and planning is lackluster, while their water management and sewage treatment activities need improvement.

This report talks about the Tiber River basin as a whole, while managing the Tiber in Rome city limits is a much different scene. The same agencies mentioned above are involved with managing the Tiber River in Rome along with a multitude of other institutions such as the Autorita di Bancino del Fiume Tevere and La Polizia Fluviale with are responsible for drafting environmental policy changes and managing the embankments and water levels, respectively (Rankin, 2015). But in order for any major policy change to be enacted on the Tiber, many of these organizations must approve or have a say in implementation. Having to engage in this bureaucratic system inevitably stalls public action and can lead to stalemates because so many organizations are involved (Rankin, 2015).

For the Tiber, public civilian groups tend to be more effective in getting immediate tangible results. One such group called Retake Rome, was founded in 2009 and aims to get rid of “Rome’s streets of mounds of litter, layers of advertising stickers and graffiti scrawled on thousands of palazzos,” including working on the Tiber riverfront (Povoledo, 2016). By going around the bureaucracy and offering their services for free, city hall has “been supportive” of their work. As long as the government is mostly uninterested in effectively cleaning up its river, groups like this one are essential to maintain some form of passion going for the Tiber’s conservation (Povoledo, 2016). 

Another local non-profit organization called Tevereterno Onlus founded by Tom Rankin also seeks to regenerate Rome’s river but in a very different way. In 2016 they unveiled their largest work yet, a series of expansive murals (Figure 14) by artist William Kendridge on the travertine embankment walls covering scenes of Rome’s ancient history, its deities, and other events (Rankin, 2016). Their work has not only beautified the riverfront by power washing it, but also gave it some personality with the artwork. They also provided a small festival of live performances to go along with the artwork, bringing in musicians and actors to entertain guests inside what they inaugurated as the ‘Piazza Tevere’ (Rankin, 2016).

Figure 14. Kendrige’s murals soon after they were unveiled lining the embankment walls (Rankin, 2016).
Figure 15. A current photo of the embankment walls and river from our trip. Time and pollution has faded the murals, which can still be seen faintly on the left side.

In recent years, the most productive interactions that Romans have had with its river have come from the Roman citizens themselves. Rankin hopes that the success of the project will “reactive[ate] the Tiber in the heart of Rome,” in the chance that a new culture of public use and restoration for the riverfront will emerge as in ancient times (Rankin, 2016).


Activity on the Tiber has never remained stagnant. It has been engineered and abused since the ancient Romans first began using it as a transportation hub and sewer discharge point. Even now in its present dilapidated state, far beneath the populace which passes over it each day, the Tiber remains a dynamic part of Rome, occasionally flooding to remind us that it is still there. And although its riverfront below encourages a culture of separation from the city, this does not have to remain the case. Retake Rome and Tevereterno Onlus serve as examples to the rest of Rome that anybody can make a difference, regardless of the government’s inaction. After visiting Italy’s most historic and dynamic city, I have faith that Rome’s river will be uplifted from its state of decay and transformed back into that holy symbol it was deemed as.

Works Cited

Aldrete, Gregory S. Floods of the Tiber in Ancient Rome. Baltimore, Johns Hopkins University Press, 2007. Accessed 17 Sept. 2019.

Alessandroni, M. G., & Remedia, G. (1999). The most severe floods of the Tiber River in Rome. Retrieved from

Boe, Ra. (2011, December 19). Fiumicino 2011, photograph.

Calenda, G., Calvani, L., & Mancini, C. P. (2003, January). Simulation of the Great Flood of December 1870 in Rome. Retrieved from

Cesari, G. (2016, June 30). Peer Review Report: Tiber River Basin Authority, Italy. Retrieved from


Dio, C. (2018, October 6). Dio’s Rome, Volume 6 An Historical Narrative Originally Composed in Greek During The Reigns of Septimius Severus, Geta and Caracalla, Macrinus, Elagabalus And Alexander Severus. Retrieved from

EU Commission. (2012, June 26). Project of the Week: Integrated River Engineering Project on the Danube East of Vienna to improve navigability and protect environment. Retrieved from

Ferri, P. (2013) The Construction of the Tiber Embankment Walls. Edazioni Kappa, photograph, Rome.

Frosini, P. “Il Tevere – Le inondazioni di Roma e i provvedimenti presi dal Governo Italiano per evitarle” – Roma – Accademia Nazionele dei Lincei  – 1977

Heiken, G., Funiciello, R., & Rita, D. D. (2007). The seven hills of Rome: a geological tour of the eternal city. Princeton, NJ: Princeton University Press.

Istituto Luce. (2016) Muraglioni del Tevere. Unknown photographer, photograph, Rome.

Lancaster, L. C. (2009). Concrete vaulted construction in Imperial Rome: innovations in context. Cambridge: Cambridge University Press.

Livius, T. (2006, November 6). Project Gutenberg’s The History of Rome, Books 01 to 08, by Titus Livius. Retrieved from

Loiwal, M. (2019, August 19). Kolkata all set for first underwater metro services. Retrieved from

Marra F, Motta L, Brock AL, Macrì P, Florindo F, Sadori L, et al. (2018) Rome in its setting. Post-glacial aggradation history of the Tiber River alluvial deposits and tectonic origin of the Tiber Island. PLoS ONE 13(3): e0194838.

Mattei, D., Cataudella, S., Mancini, L., Tancioni, L., & Migliore, L. (2006, July 13). Tiber River Quality in the Stretch of a Sewage Treatment Plant: Effects of River Water or Disinfectants to Daphnia and Structure of Benthic Macroinvertebrates Community. Retrieved from

McGrath, S. (2016, November 13). Dirty Danube: looming pollution threats to the world’s most international river. Retrieved from

Niladri, G. (2014, March 14). Kolkata Beautification, photograph. Retrieved from

Platner, S. B., & Ashby, T. (2005, March 5).  p126  Cloaca Maxima. Retrieved from*/Cloaca_Maxima.html

Povoledo, Elisabetta. “A Roman Legion of Volunteers Retakes the Tiber.” The New York Times, The New York Times, 26 Apr. 2016,

Rankin, Tom. Rome Works. Peruzzi Press, 2015.

Rankin, T. (2019, April 8). William Kentridge’s Triumphs and Laments. Retrieved from

Virgil, P. (2008, March 10). THE AENEID. Retrieved from

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