Pre 1900s Rome suffered damaging flooding on a scale unimaginable to us, a couple of times every 100 years. The Jewish ghetto area seemed to take a large share of the brunt. Much of Rome was a marshy wetland between the seven hills.
The last time the Tiber was in flood was December 2008, the last time Rome flooded was 1937, and the most recent seriously damaging flood was 1870.
There are 122 plaques hung up around Rome showing the water levels for various flood dates. The earliest plaque is from the year 1277 (however floods are documented back to the BCs). The plaques can be seen in lots of public places such as Castel Sant Angelo, Santa Maria Sopra Minerva and San Spirito in Sasso near St Peters.
Santa Maria Sopra Minerva is very near the Pantheon which is one of the low points in Rome. In fact the water would seep up through the ancient sewage system once it was inundated with flood water.
Santa Maria Sopra Minerva with Bernini’s sculpture out in front.
Back of the Pantheon showing the lower level of the ground from historical times and how much more prone to flooding it was.
In the late middle ages the flooding was most frequent and most damaging. It seems to have been exascerbated by man made activity such as property being extended out from the original banks thus narrowing the river span, and also from arched bridge designs impeding the flow. Once in flood, boats lost from their moorings and detritus from river side buildings such as mills getting wedged in the bridge arches further worsened the situation.
In some cases the phenomenon was natural, such as where sharp bends and rapids cause the flow of the water to accelerate. In one of these spots, just to the south of Tiberina Island is a fragment of the poorly positioned Ponte Rotto.
Ponte Rotto (or Broken Bridge), is the fragment of only one arch, that sits between Tiberina island and Ponte Palatino and isn’t accessible. It is the oldest Roman stone bridge in Italy. There was a wooden bridge here until the permanant stone structure was built. It earliest incarnation was built in 179 BC and further improvements followed with the arches built in 142BC. It was called Pons Aemilius (or Ponte Emilio), after the leader of the Roman Senate that had it built. There were originally 7 arches, this remaining arch was the centre. It was constructed by driving tree trunks down into the river bed and then volcanic tufa blocks interlocked to build the foundations. Travertine blocks were added later.
This bridge had repairs and rebuilds along the way. It is documented that flooding caused damage to the bridge in 1230 and it was rebuilt, again in 1557, this time with two of it’s arches being brought down and again it was rebuilt. Todays remnant bears Pope Gregory XIII s latin inscriptions detailing the renovation carried out at this time as well as his dragon heraldic symbol and his coat of arms.
In 1598 following a catastrophic flood of 4 metres, the arches closest to the Aventine collapsed and the bridge was finally abandoned. In 1887 Ponte Palatino was built and required more of the remaining section of Ponte Rotto to be demolished leaving only the current single arch.
It was poorly positioned being sited just below rapids and just before a sharp bend with accelerated water flow. It took a hammering.
Early measures to protect Rome were well under way by the 1st century AD when channels were built out near where the Tiber meets the ocean, (near what is now Fiumicino and Ostia), at a site called Portus. The channels were designed to improve the flow of water out to sea.
Note the narrow channel to the right of the photo; two were dug .
More recent steps have included such things as the widening of the river bed, the construction of 9 metre high walls along the banks of the river and in the 20th century the upriver construction of hydro electric power stations which can control the flow to a large extent. At one stage a suggestion was to divert the river completely away from the city and only leave a canal which was supported by Garibaldi himself.
This website linked below has fascinating pages on ‘Broken Bridge‘ and ‘The Floods of the River Tiber‘ and lots more. It is very interesting. http://roma.andreapollett.com/S1/roma-c4.htm
Down the steep staircases to access the riverside today, it is an unnatural environment. There are high concrete and stone walls, little nature, the homeless and some lost in a world of drug use, and a few joggers and walkers. Only the river itself continues on as it always has, raw and wild. It was one of my favourite spots in Rome. Along the walls are some murals and poetry.Ezra Pound’s Rome played in my mind all the way home to New Zealand.
O thou newcomer who seek’st Rome in Rome
And find’st in Rome no thing thou canst call Roman;
Arches worn old and palaces made common
Rome’s name alone within these walls keeps home.
Behold how pride and ruin can befall
One who hath set the whole world ’neath her laws,
All-conquering, now conquered, because
She is Time’s prey, and Time conquereth all.
Rome that art Rome’s one sole last monument,
Rome that alone hast conquered Rome the town,
Tiber alone, transient and seaward bent,
Remains of Rome. O world, thou unconstant mime!
That which stands firm in thee Time batters down,
And that which fleeteth doth outrun swift Time.