Water supply and management in Rome.
A work in progress (16th-20th Century)
By Paolo Buonora
1. Introduction
This paper stems from an hypothesis: the visible water, flowing in the Tiber river or
appearing in the beautiful fountains of Rome, finished for hiding by the time a more
complex hydraulic network. This happened not only for physiological reasons (pipes
run usually underground), but also for cultural reasons (functional uses are often
hidden), and for the urban development of the city (streams were covered and diverted).
Literature written in crucial periods of crisis in water supply or in hydraulics
emergencies related to river floods is thought to have influenced also the historical
interpretation of these aspects of the city life. In fact, this literature was often produced
by erudite men and not by technicians, and had always dealt with the Tiber River. Is it
really true that the city could not survive without the mills floating in the river and
without restoring ancient aqueducts? Also, about the system created by the popes
starting with 16th century, is that only the restoration of an ancient system or another
one, different in structure and purposes?
On the contrary, this paper will try to show how the river represented mostly the final
discharge of a more complex system of water circulation within the body of the city,
and that the center of this system can be placed outside the river. The genesis of this
system can be found in the modern age, in the period of more intense demographic
growth of the 16th century. Also if the old structures of the ancient Rome had their
importance, the characters of the hydraulic system of the modern Rome have a different
function, that can be related to a model of water supply common to most part of the
cities of Center Italy. Finally, an outline of a hypothesis will be attempted on the
evolution of the system during a long period, disregarding the chronological limits of
the archive research currently in progress.
2. Ancient aqueducts
It is difficult discuss Roman aqueducts without telling their often-repeated, long
story, concerning both their ancient building and their modern restoring. But as it’s just
upon this element that I will try to single out the differing aspects between the ancient
and the modern system of water supply, it will be necessary to deal thoroughly with the
subject. Another reason for this, is that several new studies have appeared in the last ten
years, and they present many suggestions that exceed the terms of the problem as had
been established by the classical works by Lanciani and Ashby. Anyway, it can be
stated that one of the most important examples of emancipation of humanistic
disciplines from dependencies with literary sources, is indeed the study of ancient
Roman aqueducts. Distinguishing research based upon the mere literary reconstruction
from the scientific topographic relief started with Lanciani’s studies and is one of the
milestones of archeological science1. Also Ashby, understanding the relevance of
1
R. Lanciani, Le acque e gli acquedotti di Roma antica, Roma, 1975: reprint of R. Lanciani, Topografia
di Roma antica: i commentarii di Frontino intorno le acque e gli acquedotti: silloge epigrafica aquaria /
leveling ruins, worked side by side with the engineers of the Scuola d’Ingegneria
dell’Università di Roma: Reina, Corbellini, Ducci2.
A brief summary of the history of aqueducts: the first Roman aqueduct was the
Appio (312 b. C.); it was followed by the first one coming from the Aniene river valley,
the Anio later named Vetus (272-269 b. C.), running underground for defense purposes.
In 144 b. C., Q. Marcius Rex brought in the city and then up to the Capitolium some
springs by the upper Aniene valley, with the Aqua Marcia aqueduct. In 125 b. C. the
less important Aqua Tepula arrived, by the Colli Albani, and in 40 b. C. Agrippa,
curator aquarum, added the Aqua Julia, restoring also the main conducts. In 19 b. C.
Agrippa again joined near springs of Aqua Virgo near Salone in a conduct without
raising parts, that turning beside the city hills entered the town by the Flaminia road
bringing water in Campo Marzio. In the Empire period, the building of new public baths
proceeded along with the building of new aqueducts to bring water to the thermae. After
Agrippa’s death the 240 specialized slaves employed in hydraulic works went under the
management of the emperor and the State, forming a familia publica that under
Claudius the emperor reached 700 units. These workers were anyway employed in the
usual management and supporting, while the new buildings were made under contract3.
Augustus the emperor carried out works of restorations and added new springs, and
in 2 a. C. carried the Aqua Alsetina, a bad quality one, to supply a naumachia on the
right side of the Tiber. In 52 a. C. Claudius had the two aqueducts built that Caligola
had designed in 38 d. C.: the Aqua Claudia, supplied with the same springs of the Aqua
Marcia; the Anio Novus, that drew its waters directly from the river. The subsequent
emperors engaged themselves in important works of distribution of waters inside the
city and of restoration. Only Traianus, in 109 a. C., built a new aqueduct on the right
side of the river “to supply the industrial part of the town”, as Ashby says. Alexander
Severus finally built the Aqua Alexandriana, later restored with the name of Aqua
Felice by Pope Sixtus V.
Procopio’s evidence (14 aqueducts) can be justified either as an exaggeration, or as
to include three secondary branches of the existing aqueducts4. Neglecting ancient
aqueducts came about very gradually: several evidence affirm the continuation of
restoration activity – in particular between the 7th and 9th century for the Aqua Traiana,
supplying St. Peter’s basilica and the mills on the Janiculum5. Only after the 9th century
the failure of water supply would have prompted to abandon the upper parts of the town
for using wells – not only the river – situated in the lower parts near the Tiber.
Hence let’s consider in a more specific way what a Roman aqueduct was and what
were its purposes: This analysis will be performed following the many suggestions that
T. A. Hodge’s book contains6. He remarks that only the raising parts of aqueducts
memoria di Rodolfo Lanciani, in Atti Lincei, Ser. 3., Mem. scienze morali, storiche e filologiche, Vol. 4.,
seduta 18 genn. 1880, Roma 1880.
2
T. Ashby, Gli acquedotti dell'antica Roma, Roma, 1991, note to translation and forewords.
3
A. M. Liberati Silverio, for the X Ripartizione del Comune di Roma, drew a general map of the
Campagna romana 1:100.000, representing the most complete and upgraded outline of the aqueduct layout: Il trionfo dell'acqua. Atti del convegno "Gli antichi acquedotti di Roma. Problemi di conoscenza,
conservazione e tutela", edited by di A. M. Liberati Silverio, G. Pisani Sartorio, Roma 1986, pp. 35-46.
4
Differently from Ashby, A. Betocchi, Le acque e gli acquedotti di Roma antica e moderna, in
Monografia della città di Roma e campagna romana, Roma 1881, try to indicate three others “waters” for
matching with the total number given by Procopio.
5
T. Ashby, Gli acquedotti, cit., p. 32.
6
T. A. Hodge, Roman acqueducts and water supply, London, 1992. Hodge does not mean to offer a
chronological survey of roman aqueducts, as they changes in time, nor a repertory to use in a
2
captured attention, and not the longer parts underground; not enough of this has been
considered in Hodge’s opinion “the water supply system as a whole. In a word, the
aqueducts have generally been studied rather as archeological monuments than as
functioning machines”7. Roman aqueducts in fact were not built for drinking and
washing: these basic needs were just satisfied, and continued to be, with the system of
springs and private cisterns. They were instead a sign of luxury and urban status that
satisfied civic pride, a matter the symbolic interest of which is underlined by a series of
monumental and artistic uses of their water.
In other words, there were “two quite separate water systems operating in parallel
and independently, fulfilling different purposes and observing different rules”, and the
primary role of the aqueduct is still to demonstrate8. What is really important is the
public and civic relevance of the aqueduct as an enterprise, compared to the private
character of the cisterns. Public baths were the sign of civil living, and Romans often
made this aspect in colonial cities perceivable: aqueducts were for their own needs, not
for native inhabitants who continued to employ springs and cisterns9.
Let’s now examine the structural elements of the aqueduct as a system. When
designing an aqueduct the quality of waters was firstly examined; afterwards difficulties
in the road were appraised: it was neither possible to build very high arches nor very
deep galleries, and often the choice was to border the hills. It was possible also to pass
under the valleys by employing siphons, but in the Ashby’s opinion, Romans never
realized the capacities of their own cement pipes: “resistance to compression of their
hydraulic cement exceed the safety standard accepted today” 10. In fact, they did not
need pressure aqueducts as on the contrary the distribution system avoided high
pressure carefully.
Hodge remarks that the aqueduct in Roman age was not a closed pipe: from a
hydraulic point of view it must be considered an open channel, an artificial river. It is
not true that lead pipelines could poison people: the internal surface of pipes was
quickly covered with limestone to isolate them, and water never stayed inside for a long
time11. It is important to underline this problem of aqueducts service: the “tartaro” in the
Italian term, or “sinter” in the German one. Romans never solved this problem that
produced a progressive reduction in supplying capacities. Deposits found in the
archeological works are very impressive: the carefully worked calcareous stone was
geographical order: he follows the course of the water inside the parts of the typical roman aqueduct.
About ancient aqueducts in general see also T. A. Hodge, (edited by), Future currents in aqueduct
studies, Leeds, 1991; R. Tolle-Kastenbein, Archeologia dell’acqua. La cultura idraulica nel mondo
classico, Omegna 1993; Utilitates necessaria: sistemi idraulici nell'Italia romana, a cura di I. Riera,
Milano, 1994. About roman aqueducts in particular, see G. Panimolle, Gli acquedotti di Roma antica,
Roma, 1963; P. Pace, Gli acquedotti di Roma e il "De Acqueductu" di Frontino. Contesto critico,
versione, e commento, Roma, 1983 e quelli più recenti C. Bruun, The water supply of ancient Rome: a
study of Roman imperial administration, Helsinki, 1991; P. J. Aicher, Guide to acqueducts of ancient
Rome, Wauconda, 1995.
7
T. A. Hodge, Roman aqueducts, cit., p. 4
8
Ibid., p. 48.
9
Ibid., p. 50.
10
T. Ashby, Gli acquedotti, cit., p. 52; the case of Alatri, that in fact he mentions, seems to affirm the
contrary.
11
T. A. Hodge, Roman aqueducts, cit., p. 2
3
employed to replace travertine in churches – and in fact its chemical structure is very
similar to the “natural” one in marble12.
For the distribution in town, waters were often filtered in multiple reservoirs; it was
afterwards distributed by the means of principal castella (247 at the time when
Frontinus writes) and still after to the secondary and private ones, the number of which
is unknown. This cascade distribution allowed to control pressure in some critical points
– not the pipes, but taps. The measurement of water, calculated in quinarie (40 m3 in a
day), was practically reliable: the copper intakes, the pipe’s regular size and mostly the
water level in the castellum, regularly kept at the same height, leaving exceeding water
to flow away guaranteed good results.
Exception made for some few private houses with their own pipeline, domestic
supply was assured by public fountains. In Pompei, where it is still possible to precisely
reconstruct their locations, fountains were placed in a number and in places as no house
had a fountain more than 50 meters distant; of course, the arrival of an aqueduct nearby
modified everyday life: no more queues to take water and to irrigate gardens. Pipes,
connections and other pipelines distributed waters: usually every user had his own pipe
from the castellum to his house, as many parallel pipings have been found, and not a
network distribution system13. Also a castella with a tank separated in three parts has
been found, as Vitruvius recommended, in Rome a distribution of the water of the same
aqueduct relating to the profile of users has never been made: different supplies were
performed relating to different parts of the town. The division suggested by Vitruvius
(public fountains, public baths, private users) was not necessary in Rome because there
were many aqueducts and different employments could be performed – as will be
shown further on – in a more sophisticated way, specializing an entire aqueduct to some
users and not to others.
There were taps, but usually the system worked with a continuous flowing of water.
From the hygienic point of view, the great amount of water arriving in Rome (Frontinus
affirms it was almost 1 million m3 in a day) was not useless at all, even if many cities
functioned well without sewers. In other words, the continuous flow could not be
considered a waste of water: “the only guarantee for public health remained the
continuous washing of drains”14. As concerns rain drainage, water was collected in the
impluvium of the roman house, it was kept and used; also human dejection was often
kept, but there were anyway drains along the roads, and sometimes open sewers.
Relating to water supply inside Rome, no reconstruction can be made without
considering the evidence of Vitruvius and Frontinus. Hodge remarks that Vitruvius is
often not the best teacher on this subject; moreover, he does not tell how ancient
Romans built, but how they should build: for instance he was absolutely contrary to lead
pipes, that we nevertheless find very frequently. As for Frontinus, he was not an
engineer but a functionary, not very interested in technical subjects: he saw flowing
water as an administrative object, a service supplied following a general map of the
system; this mental map is not an engineer map, but rather the diagram of a manager.
Frontinus was born at the end of Tiberius kingdom and died in 103-104 a. C.; he was
appointed to the cura aquarum in 97 a. C., and he is considered a sympathizer of the
12
Ibid., cit., p. 231. See the limestones of the Aqua Marcia in Il trionfo dell'acqua. Atti del convegno, cit.,
fig. 3 a p. 38. For some examples of calcareous deposits, see I. Riera, Le testimonianze archeologiche, in
Utilitates necessaria, cit., pp. 234 e 250.
13
T. A. Hodge, Roman aqueducts, cit., p. 320
14
T. Ashby, Gli acquedotti, cit., p. 53.
4
senatorial party. His text does not deal with the course of single aqueducts, but focuses
on problems of measuring waters and the needs for supply.
From his own survey, the water furnished was more than the disposable amount, and
moreover measured at the springs it seemed to be almost double the quantity that the
water really supplied in town. As he used a mere geometrical method of measuring the
final pipes (fistulae), his evaluation of flow was not reliable; a modern evaluation15
assigned to the roman quinaria a value of 0,48 liters per second for an amount of a
million m3 in a day, supplied but the 8 aqueducts functioning at the time of Frontinus16.
This value is surprisingly similar to the modern roman oncia. Probably measuring at the
beginning and at the end of the aqueduct was not comparable, but anyway Frontinus
tried to eliminate many abuses and irregularities in the previous administration of the
cura aquarum. They concerned irregular diversions and the respect of public property
of the terrain where an aqueduct was placed; he carefully assured a different use for
waters relating to their characteristics, separating domestic, industrial, hygienic and
irrigation uses.
In spite of the declared purposes of his Commentari, presenting guidelines for the
administration of roman waters, political purposes of the pro-senatorial Frontinus
appear by the repeated criticism to the previous management, by often comparing
himself with Agrippa and by the preparation of maps: “Frontinus therefore presents in
his treatise an image of himself as a loyal lieutenant of an enlightened princeps
determined to correct the abuses of the past”17. Also if his evidence is the source for all
studies on roman waters, his text is “a document presented to celebrate its author and
the policies of the emperor who appointed him”18.
A study by Evans remarks how few are the things we know about water supply
inside ancient Rome, and tries to answer some questions on the basis of the evidence of
Frontinus himself, as it remains the only statistic we have. There has been a long
discussion about the amount of the waters flowing in the ancient aqueducts, calculated
either in a million m3 in a day, or only in 5 or 600 thousands m3. However his text gives
also some information upon the water supply of suburban region, as he claims that
almost one third of the water was distributed before getting in the city walls.
As stated, water arrived flowing to castella, whence it was distributed. Vitruvius’
theory, the main tank should be divided in three parts to supply separately fountains,
public baths (he considered that they brought in relevant taxes to the state treasure) and
private houses. It must be noted that in his classification there are no mills or industrial
users. As for the public users, Frontinus indicates public buildings (thermae, circus,
etc,), the castra, the munera (that were both monumental fountains and emergency
basins), and the lacus (where exceeding water flowed and could be drawn). Let ‘s
review again every aqueduct, considering the specific uses.
15
C. Di Fenizio, Sulla portata degli antichi acquedotti romani, in «Giornale del Genio civile», 14 (1916),
pp. 227-331. See also P. Branchini, Nota sulla misura adottata in Roma per la dispensa delle acque,
Roma, 1857.
16
As the Aqua Alexandriana e Aqua Traiana did not existed yet, only evaluations for the Aqua Virgo can
be compared: their order of measuring is similar: 2.504 ancient quinaria versus 3.840 modern roman
oncie in the evaluation made by Betocchi for the papal aqueduct. In his calculation, the amount of water
for each Rome ancient inhabitant was still higher than the disposable supply for the Romans in the new
Capital City of Italy.
17
H. B. Evans, Water distribution in ancient Rome: the evidence of Frontinus, 1994, p. 61.
18
Ibid., cit., p. 63.
5
The Aqua Appia was brought in the lower parts of the town that were only supplied
by springs, also for supplying the river harbor (an example was the port of the romanEtruscan site of Cosa) and commercial activities of the Campo Boario. It followed a low
course and brought in a medium amount of water, supplying many lacus. Its
maintenance up to medieval period in fact is not clearly distinct by the Marrana stream,
that arrived under Aventine hill and near St. Maria in Cosmedin, as will be seen further
on. The Anio Vetus flowed higher (it was provided with 35 castella), but not so much to
supply the highest parts of the town; its function seems to be limited to the new
expanding eastern districts, Esquiline hill. The modest quality of its waters convinced
Frontinus to suggest a general use of it, to keep the better drinking water of other
aqueducts19.
The Aqua Marcia, for its quantity and higher level of distribution (51 castella)
succeeded in supplying with several branches almost every district of the city, including
the highest hills. Its excellent quality supported its utilization as drinking water for
private users and public lacus, and kept its fame up to the restoration of Marcia-Pia
aqueduct in 1870. The Aqua Tepula, an adding stream coming from the Castelli Romani
using the rising arches of the Marcia with its own pipeline, was worse in quality and
was distributed to private users mixed with the Julia and with some Marcia for general
purposes. The Aqua Julia, in spite of its similar quality to the Tepula, was mostly
employed for public buildings.
The Aqua Virgo was instead an important aqueduct for distribution; it didn’t worked
for the high parts of the city but just for the lowest ones of the Campo Marzio: a
relevant part of it supplied the suburban districts. In Rome it supplied mostly public
buildings.
Aqua Claudia and Anio Novus flowed parallely in separate pipelines, and integrated
one another in a some complex way furnishing both the emperor’s palace (Domus
Aurea and Palatinus hill) and a spreading private network, arriving in Transtiberim to
increase the modest supply of other aqueducts. Their remarkable branches were the
Arcus Celimontanus and a branch flowing high to supply the Marius Trophy on the
Esquiline20. Claudia’s quality was excellent, and the amount of water of the two
aqueducts together was a special reason of pride for Frontinus.
The Aqua Alsietina of the Martignano Lake was driven to town especially for the
naumachia in Transtiberim, and was forgotten after the arrival of the Aqua Traiana. The
latter finally supplied good drinking water directly to the districts of the right side of the
Tiber; the discovery of channels and mill stones confirm the reconstruction made by
Lanciani in his Forma Urbis21. Its quantity was enough to distribute it on the other side
of the Tiber, in the opposite direction than before. Without Frontinus’ evidence, we
Evans talks about an irrigation and industrial employ: ibid., p. 81, and further at p. 82: “used primarily
for industrial purposes”. But the text of Frontinus, 92, talks only about gardens and of “baser needs of the
city” (in the same translated version by Evans), not about industrial uses. His interpretation seems to be a
misunderstanding: original text say: “in hortorum rigatione, atque in ipsius Urbis sordidiora exiret
ministeria”. In the ‘800 version of B. Orsini it sounds: “all’innaffiamento degli orti, e che finisse ne’ più
lordi servizi della medesima Città”, Sesto Giulio Frontino, "Commentario di S. G. Frontino degli
acquedotti della città di Roma" con note di B. Orsini, Perugia, 1805, pp. 148-149. I will turn back further
about the meaning of these “industrial” interpretations.
20
G. Tedeschi Grisanti, Primo contributo a una livellazione urbana sistematica degli antichi acquedotti
di Roma, in Il trionfo dell'acqua. Atti del convegno, cit., pp. 59-72, affirms that the Trophy of Mario
could not be supplied by the Aqua Julia, and was probably the terminal point of a branch of the Claudia.
21
R. Lanciani, Forma urbis Romae, Roma 1990, pl. 27.
19
6
cannot exactly affirm the aqueduct purposes, although the demographic growth of
Transtiberim created of course needs in water supply.
Aqua Claudia/Anio Novus are the main water suppliers both for private and for
public users: this system appears to be the backbone of water supply of the imperial
city. Exception made for many springs inside the town that continued to play their role,
other aqueducts showed particular specialization. This specialization is organized for
functions and for geographic areas: some waters had a wide spreading (the Marcia as
drinking water, the Tepula and the Julia for more general purposes); others had
concentrated supply for a less number of users, especially public ones (the Virgo, the
Anio Vetus). To private uses prevailing in water supply and irrigation of suburban
districts corresponds inside the city a slight prevailing of public uses (44%) on private
ones (40%), and an important presence of imperial uses (20% in nomine Coesaris). The
older republican aqueducts continued to play their role supplying public basins, the
lacus.
A separate problem concerns special uses. Irrigation first of all, as it is known to
have been relevant in the suburban area: the amount of water necessary for irrigation is
an enormous quantity compared to the basic needs of drinking and washing, also
considering that in ancient times it was used for continuous flowing. Mechanical
irrigation was not practiced, for the high costs and because it was not possible to raise
waters very high. There is evidence about the Aqua Cabra coming down by the
Tusculum hill, which was employed in an irrigation channel: maybe it was utilized with
a rotation system among users, as it had become common practice in the middle age.
But Roman agriculture was in fact dry farming; it seems that the Romans diverted water
employed by Berber farmers to supply thermae in their colonial cities22.
The most interesting subject anyway concerns industry: it will give us the essential
point to appreciate the differences between ancient and medieval-modern situation23. In
Hodge’s opinion – but Evans too seems to be very interested in this matter – water was
employed in mines to wash minerals and in town by fullers, but especially to move the
hydraulic wheels of mills. The role of hydraulic mills was not as secondary as historical
tradition believes, and it is also uncertain if the vertical “roman” wheel is an evolution
of the “greek” horizontal one: a simple mechanism could be more important than power,
in those times. Anyway, a vertical wheel is particularly efficient if moved by an upper
flow, not if moved only by a flowing stream. Hodge is not convinced by arguments to
justify a rare utilization of mills in the roman world (the only discoveries in Rome are at
the Janiculum and at the Thermae of Caracalla): the Romans knew the structure and
function of hydraulic mills very well24. Moreover, aqueducts were an ideal supply for
mills. In other words: “the only reason that we think water-mills were rare is that we
have not found many, and this may reflect simply a failure either of archeological
evidence, or of our interpretation of it”25. However, how many among the hundred of
mills cited in medieval documents have archeologists discovered? As the water used by
the mill could be introduced in the aqueduct, this utilization could be have been
22
T. A. Hodge, Roman aqueducts, cit., p. 252.
Ibid., pp. 254 onward.
24
Exception made for Vitruvius, see the archeological evidences in Il trionfo dell'acqua. Acque e
acquedotti a Roma (IV sec. a. C. - XX sec.). Mostra organizzata in occasione del XVI Congresso ed
Esposizione internazionale degli acquedotti, Roma 31 ottobre 1986 - 15 gennaio 1987, edited by Comune
di Roma e IWSA-ACEA, Roma 1986.At the beginning of the volume, at tab. IX, we see a fresco of 3rd
century, placed in St. Agnese catacombs, representing the vertical wheel of a mill.
25
T. A. Hodge, Roman aqueducts, cit., p. 256
23
7
practiced at the birth of the aqueduct and Frontinus would never have talked about it;
so, there could be a wide hydraulic network for mills, completely unknown to us. In
fact, ruins of a serial mills construction have been found in Barbegal, supplied by their
own aqueduct, different by the parallel one used for the water supply of the city of
Arles. In the archeological reconstruction, it seems to be a system of eight buildings
with two wheels each, a truly industrial system: “how many Barbegals are there
awaiting discovery?” Hodge asks, affirming “this may well be the largest and most
important question raised by this book”26.
His thesis must be discussed carefully, not only for the importance that author
himself place in it: is it only a provocation, or a fantasy? In fact the discovery of
millstones in 1990-1991 under the American Academy on Janiculum confirms the
existence and the importance of those mills27. Anyway, the fact that not a lot of mills
have been found does not prove, and does not exclude, that they really existed; even if
wooden parts can disappear in time, mill stones are a durable part, and it’s easy to
discover it. While it is usual to find marble parts from ancient buildings employed again
in modern ones, no ancient mill stone has yet been found, let’s say, on the ground floor
of a medieval church.
Hodge’s opinion seems to be restricted too much to the technological aspects of the
problem: adopting a technology is not only a technical matter, but also an economical
one. The main argument of economic historians on this subject is that the presence of so
many slaves made the labor saving use of mills not necessary, and that the different
conditions made it an essential element of development in the urban medieval economy.
In fact, the same number of mills would have a quite different relevance in imperial
Rome with one million inhabitants and in the pope’s city, with a modest population.
3. Modern aqueducts
We will now examine the events concerning water supply after the ancient age 28. In
537 a. C. the Gothic army of Vitige besieged the Byzantine troops of Belisarius, and
26
Ibid., p. 261
H. B. Evans, Water distribution, cit., p. 130. References by Evans are the followings: O. Wikander,
Water mills in ancient Rome, Opuscola Romana, 12 (1979), pp. 13-36, 1979; Id., Water mills and
aqueducts, in Future currents, cit., pp. 141-148, 1979; M. Bell, III, Dig we mustn't during the World Cup,
AMACADMY, Newsletter of the Academy of Rome, fall 1990, 8; Id. The mills of the Janiculum,
Classical Society of the Academy of Rome Newsletter, December 1990, 9; L. Richardson, The aqueduct
of the Transtiberim and the American Academy in Roma, Classical Society of the Academy of Rome
Newsletter, December 1990, 6-8. About the ruins on the Janiculum, see also T. Ashby, Gli acquedotti,
cit., p. 363:Ashby believed that the main channel was not the one named by Lanciani, as later a specus
was found under the American Academy, see A. W. Van Buren; G. Ph. Stevens, Memoirs of the America
Academy of Rome, I, 1917, pp. 59-61. Images and information concerning the conduit discovered under
the American Academy are in Il trionfo dell'acqua. Acque e acquedotti, cit., pp. 118-119: it is a derivation
parallel to the Aqua Traiana, with channels and reservoirs; there have been found the mill stones
mentioned above.
28
For a popular history of these facts, see C. D'Onofrio, Acque e fontane di Roma, Roma 1977. Coeval
sources and bibliography on this subject are many, also if sometimes they are not original; see: L. Peto,
De restitutione ductus acquae Virginis, Roma, 1570; R. Fabretti, De acquis et acqueductibus veteris
Romae, Roma 1680; F. Fontana, Relazione sullo stato vecchio e nuovo dell'Acqua Felice, Roma, 1696;
C., Fontana, Utilissimo trattato delle acque correnti, diviso in tre libri, Roma, 1696: Book III was
devoted to the aqueduct from Bracciano Lake; A. Cassio, Corso delle acque antiche portate da lontane
contrade fuori e dentro Roma sopra XIV acquedotti e delle moderne in essa nascenti, Roma, 1756-1757;
N. M. Nicolai, Sulla Presidenza delle strade ed acque e sua giurisdizione economica, Roma, 1829; C.
27
8
interrupted the aqueducts to deprive the city of water. Two years after they entrenched
themselves at the crossing point of the arches of Aqua Claudia and Marcia: the
Byzantine also made some walls inside the pipelines to prevent their attacks inside the
town. But we know that a war was not necessary to stop the water supply of a Roman
aqueduct: the limestone was sufficient to stop it in time, if maintenance was performed
frequently. In fact, after the war, aqueducts were restored and maintained until the 8th
or 9th century. After that time only some Aqua Virgo continued to arrive in town, also
because the majority of the conduct was underground and it was not exposed to damage
of arches. In my opinion, an important factor of its long survival was due to the minor
quantity of limestone, as the quality of its water was different from the one of the main
ancient aqueducts.
As said, the Aqua Virgo went a long way to get in town from the northern part,
passing under Pincio hill and arriving in Due Macelli street behind the modern Trevi
fountain, to the terminal reservoir in Seminario street. At the time there was of course
some maintenance on it, but the drawing of waters was made in a lower point, near
Boccadileone, with a stream of water less than before. It must be considered that in the
humanistic discovery of ancient roman techniques the city of Rome does not have a
special role. Siena for instance was a more important center for the rise of new
hydraulics: Leonardo da Vinci also can be placed in this tradition. But Taccola and
other engineers of Siena in the 14th-15th century studied as an example not a Roman
aqueduct, but mostly the Segovia one, as it was well known for the intense commercial
relations between Italian and Hispanic ports29. Stopping the ancient aqueducts also
influenced the evolution shape of the city: Rome in medieval age was rebuilt in the
northern part, that was better supplied by vatican springs, by the river and by the
medieval Virgin aqueduct.
D’Onofrio, following Lanciani, often talks about the discussion between Bacci and
Modio about the water quality of the Tiber River. In his opinion the river had an
important role in supplying the city: an inadequate policy in restoring aqueducts was
justified with the belief of a healthier quality of the river waters 30. In other words a
necessity would be presented as a choice. In fact not having real drinkable water was
the origin of a lot of diseases and also made children wine consumers. But maybe the
literary evidence of discussion between Bacci and Modio is not enough to demonstrate
that the inhabitants of Rome drank the river water: in town there were many other
springs to satisfy in a better way the needs of drinkable water. The political essence of
these writings is confirmed by the circumstance that Pope Giulius III in that time took a
part of the Virgin water for his own needs i. e. to supply Villa Giulia. In Bacci’s
Fea, Esame storico-legale-idraulico dei sifoni impiegati pei condotti dell'acqua Paola, Roma, 1830; Id.,
Storia delle acque antiche sorgenti in Roma, perdute, e modo di ristabilirle. Dei condotti antico-moderni
delle acque Vergine, Felice e Paola, e loro autori, Roma, 1832; N. Cavalieri San Bertolo, Sulle acque
della moderna Roma e sui metodi usati nella distribuzione di esse pei pubblici e pei privati commodi
della popolazione, Roma, 1859; R. Marchetti, Sulle acque di Roma antiche e moderne, Roma, 1886; F.
Mastrigli, Acque, acquedotti e fontane di Roma, Roma, 1928 (s. d.); P. Pecchiai, Acquedotti e fontane di
Roma nel Cinquecento, Roma 1944; M. Pediconi, L'approvvigionamento idrico di Roma, Roma 1967; A.
Betocchi, Le acque, cited above.
29
Gli ingegneri del Rinascimento da Brunelleschi a Leonardo da Vinci. Catalogo della mostra, Firenze
1996-97, edited by P. Galluzzi, Firenze 1996; this exposition was first edited in Siena with a similar title:
Prima di Leonardo. Cultura delle macchine a Siena nel Rinascimento. Catalogo della mostra, Siena 9
giugno - 30 settembre 1991, edited by P. Galluzzi, Milano 1991.
30
It is the thesis of C. D’Onofrio, Il Tevere, Roma 1980, p. 77: “as in general every water, especially
streams, it had a purifying character and value ”.
9
opinion, who claimed the healthy virtue of the Tiber water, sounds in fact like a
justification for his action.
The works of Lanciani represent an excellent point of view not only for ancient
situation, but also for modern water supply: sometimes old structures were still working
at his time. It must be considered that on the one hand he was trying to distinguish
ancient ruins from the modern structures, and on the other, he could see a long period
situation, not yet destroyed by the changes of the Capital city of Italy. First of all, he can
perceive in a very concrete way the quantity of the “underground” water of Rome: “it is
difficult to conceive an idea of these underground waters. In 1875, during the works for
building the main sewer in Babuino Street, drainage machines took away sixty days’
time six hundred and fifty thousands m3 of spring waters”. In Rome, he wrote, it was
enough to “descend at a 5 meters deep, in the lowest parts of the town, to find the
beneficial stream”31.
There were many more springs in town32 than the ones named by Frontinus, as he
talked only about the medical ones. There was Aqua Mercuri, that originated from
Celius hill and arrived in modern times to supply the St. Giorgio mill by the basin of St.
Anastasia: in the same place there was, by that time, a lavatory, then a paper mill,
finally a fuller. The conduct along the Circus Maximo was in part a modern, in part an
ancient construction, and until 1750 it was an open channel; at Cerchi street it flowed
almost 9 meters higher than the Cloaca Maxima. There was Flumen Almonis, with
several springs joining it, which I will discuss later; there was a fons Juturnae on
Palatinus hill33; springs Lautolae, Lupercale, Pico Spring, a public tank that existed
before the Aqua Appia, the Tullianum spring, the Fontinalis waters, the fontis arae, the
Esquiline spring, the damasian water between Janiculum and Vatican, Vatican springs,
Janiculum springs and some others.
Anyway, as regards Modio’s argumentation34 or the real needs of the city, it was
finally decided to begin the restoration of the Virgin aqueduct. An unsigned project with
a relevant urban meaning35 planned the drawing of Salone springs, the restoration of the
aqueduct and the building of a certain number of fountains to distribute water in the
center part of Rome. Works were begun in 1562 by Pope Pius IV: there are evidences of
these works in civic councils of 1560-1570; the network pipelines, originally planned in
stone, were made in clay36. The network of beautiful renaissance fountains, made
mostly under pope Gregorius XIII, supplied the whole center of the city. The traditional
falling system of distribution forced Giacomo Della Porta to build the Campo de’ Fiori
fountain under the ground level, to attain enough pressure; but in Spagna square it was
31
R. Lanciani, Le acque, cit., pp. 217-218.
Ibid., pp. 220 ss..
33
Probably it is the same water employed in the saltpeter manufactories in the modern age: the
manufactory had basins to wet the saltpeter ground, and in the boiler room there was a big basin supplied
by a continuous spring: P. Scavizzi, La salnitriera al Palatino. Il luogo e la fabbrica fra metà
Cinquecento e inizio Ottocento, «Archivio della società romana di storia patria», 120, pp. 211-258,
especially pp. 218-220.
34
G. B. Modio, Il Tevere, di M. Gio. Battista Modio. Dove si ragiona in generale della natura di tutte le
acque, et in particolare di quella del fiume di Roma, Roma 1556.
35
In the opinion of C. D'Onofrio, Acque e fontane, cit., p. 48, the manuscript was made in 1535-1536 by
the pope’s librarian Agostino Steuco, who in fact wrote De aqua Virgine ad Urbem revocanda, Roma
1547.
36
See the epigraph dated 1726 showing the spreading of water from the main tank, C. D'Onofrio, Acque e
fontane, cit., p. 57, fig. 37.
32
10
necessary to wait until the Paola water arrived, to let Bernini install the Barcaccia
fountain.
There was in fact the problem of other sources of supply. Between restoring the
ancient Aqua Alexandriana and the Traiana one, the first was chosen to support both
the pope’s residence in Quirinale and the Villa of Pope Sixtus V on the Esquiline hill.
The work was planned under Pope Gregorius XIII and performed by Sixtus V (Felice
Pieretti, whence the name of Felice for this water). From the spring point of Pantano dei
Grifi between Montecompatri and Colonna the water was brought to Rome with a lot of
difficulties and money. Since the technician Giovanni Antonio Nigrone performed
wrong leveling, the architect Matteo Bartolani failed in tracing the aqueduct and only
his substitute Giovanni Fontana succeeded in carrying water up to the Esquiline hill in
158737. Starting from the terminal tank and fountain, water spread in the direction of
Monte Cavallo, Madonna dei Monti, Campo Vaccino, Santi Apostoli, Colonna Traiana
and also towards Villa Medici on Pincio hill. In 1588 Campidoglio hill, which since
roman times had been supplied only by cisterns, had a part of the new water, and at the
beginning of 17th century the Felice water appeared also in front of Laterano palace, to
supply the fountain underneath the obelisk.
In 1612 a lot of new water arrived on the Gianicolo hill: it was the Paola water,
named by Pope Paulus V. Why so much water in a part of the city with a few
aristocratic palaces and wealth? The Discorso sopra i profitti da cavarsi dall’acqua di
Bracciano38 of Pompeo Targone answers this question in a very clear way: keeping
water in closed pipelines (“it should never touch the ground”) to avoid pollution, the
water would be employed before to supply mills of a unique system, then it would have
brought in the city pipelines.
Until then, the town on the right side of the river could employ several springs: those
irrigating gardens of Belvedere and the Vatican spring that Pope Damaso (366-384)
discovered and closed in a pipeline. Only in 1601 a little part of Felice water arrived in
Transtiberim, because of the ultimate ruin of the St. Maria Bridge (or Ponte Rotto). So
after some time the problem of supplying Transtiberim was worked out by restoring the
Aqua Traiana. The nature of this new aqueduct was in fact different: “even if Traiana
and Paola waters are usually considered the same thing, there is a big difference
concerning their origin, their nature, their quality. The Aqua Traiana was supplied by
very clear and healthy springs”39, while the Paola water brought mostly the water of
Lake Bracciano.
The water of this lake was bought by duke Orsini with the money of the city
(Camera Catitolina): but in fact it was managed by the State Administration (Camera
Apostolica). In the construction, work was performed by Pompeo Targone, Giovanni
Fontana and Carlo Maderno. Finally the Paola water, as the Traiana in ancient times,
crossed the Tiber to supply fountains in Giulia street arriving up to Montegiordano,
Orsini’s residence, and later passing on the Tiberine Island up to the Marcello theatre
and to Savelli’s houses.
37
L. Quilici, Il sistema di captazione delle sorgenti, in Il trionfo dell'acqua. Atti del convegno, cit., pp.
47-58, affirms that the strange leveling mistake of Matteo Bartolani, in 16 th century, was depending upon
the purpose to use the ancient catchment basin of the Aqua Alexandriana; after he tried to raise the water
level of the spring hoping it would flow into the new aqueduct, Giovanni Fontana worked out the problem
using higher springs, and the first tank was employed for supplying some mills. These mills are the
subject of a study by Scavizzi, about which I will discuss further.
38
For this text, see the appendix; it is referred in C. D'Onofrio, Acque e fontane, cit., pp. 296-7, note 2.
39
R. Lanciani, Le acque, cit., p. 375.
11
The choice of employing the lake waters directly instead of ancient Vicarello
springs, the quantity and power of the flow itself, too much for the weak structure
restored by the popes, all prove that the main purpose was to supply energy. Mills were
finally built between 1678 and 1682 with the clear aim to support the entire mill activity
of the city if the Tiber and the Marrana had failed40.
Aqueduct work were almost 270.000 scudi for Felice water and 397.000 scudi for
Paola water; there is uncertain information about the Virgin water, as it was usually
managed by the Camera Capitolina. Works and management were supported by luoghi
di monte and specific taxes; Felice water in 1590 depended on the sixtine Congregatio
super viis, pontibus et fontibus, but in 1612 the Paola water depended on its own
Congregatio. Also if management was different, the Camerlengo had a central role, for
its being directly subordinate to the pope, in coordinating politics of supplying41. In
1701 a unique management for Virgin and Paola water was decided, mostly for
supporting the Virgin with the higher resources of the Paola; only in 1742 there was a
unique Presidenza for all three waters.
The precise work of Paola Scavizzi42 clearly shows how the hydraulic network
worked to distribute water inside the city and the administrative management. Of course
it is very difficult to describe the whole as a static system: the network expanded in time
both for public and for private enterprise. To promote its development, private
diversions would be free if the owner built a fountain on an external wall of his house.
As mentioned before on the unit of measurement, the oncia, is very similar to the
ancient quinaria employed by Frontinus. The amount of water was measured with the
diameter of the initial pipes (fistole) without considering the speed that was not possible
to calculate yet43. Only in the 19th century a reliable evaluation was made, showing a
bigger flow, with pipes of the same diameter, of the Felice and Paola water compared to
Virgin water44. How could papal technicians assure a correct distribution to every single
user? Differences were in part balanced by a different measure of initial pipes or a
C. Cancellieri, L’acquedotto Paolo (secc. XVII-XX), in Il trionfo dell'acqua. Acque e acquedotti a
Roma, cit., pp. 225-21: see the project of dom. Giuseppe Paglia.
41
M. Morena Donnici, Evoluzione storico-legislativa delle magistrature preposte al rifornimento idrico
di Roma (secc. XVI-XIX), in Il trionfo dell'acqua. Atti del convegno, cited; see E. Marconcini, La
“magistratura delle acque” e la sua evoluzione dal XVI secolo al 1860, in Il trionfo dell'acqua. Acque e
acquedotti a Roma, cit., pp.259-265, referring the work of Morena in M. G. Pastura Ruggiero, La
Reverenda camera apostolica e i suoi archivi (secc. XV-XVIII), Roma 1984.
42
P. Scavizzi, La rete idrica urbana in età moderna, in «Storia della città», IX, n° 29, pp. 77-96. See also
M. Casciato, S. Mornati, C. P. Scavizzi, Il modo di costruire. Atti del 1° seminario internazionale (Roma,
6-8 giugno1988), Roma 1990.
43
About the measure of current waters and the birth of modern hydraulic, see C. S. Maffioli, Out of
Galileo. The science of waters (1628-1718). Foreword by Richard S. Westfall, Rotterdam 1994 e P.
Buonora, Gli ingegneri e il Tevere: il percorso della teoria idraulica, in I rischi del Tevere: modelli di
comportamento del fiume di Roma nella storia, Atti del seminario di studi (Roma 23 aprile 1998), in
course of publication.
44
P. Scavizzi, La rete idrica, cit., note 17, p. 91: by information of the enterprise ACEA, slope is m. 4 on
km 18, 500 for Virgin aqueduct (0, 2 per km); m. 11 on km 27 for Felice aqueduct (0, 4 per km); m. 88 on
km 32 (2, 75 per km) for Paolo aqueduct, that however has several different slopes. Evaluations about
flood, complicated by the difference between the “double” oncia of Virgin and the “simple” oncia of
Felice and Paola (usually accepted as modern roman oncia), are different between authors: oncia flood is
evaluate about 0,46 liters per second, but evaluations about the entire flood are different. For Betocchi
Virgin aqueduct brought once 3.840 in 24 hours, Felice 535, Paola 2.000. For Corsetti Virgin aqueduct
brought 40 m3 in 24 hours, Paola aqueduct 20 m3. Prony e Scaccia give similar evaluations, but Rondelet
affirms that the amount was much bigger: m3 180.500 in total in 24 hours: 94.181 for Paola, 65.782 for
Vergine, 20.537 for Felice.
40
12
different price for oncia: in practice the price of an oncia of Virgin water was half an
oncia of Felice or Paola water. The main uncertainty in distribution was in fact the
diversion point: pipes section could be round or square, they could be placed or oriented
in a different way and more than this they could work as a siphon45. The siphon system
of distribution was abandoned after the arrival of the Felice water, as its flow was faster
than the Virgin one. This difference prompted a more precise measure to be made by
introducing measure boxes for single users after the main tanks46, or also on the main
conducts. In a tax division of 1756 for works on the pipelines of Felice water, the 194
pipes counted are joined to conducts, to main tanks, to secondary ones, to the waters
just employed by public fountains: the amount of water was 1.127 once.
We have a description for the Paola water, concerning 204 users, by a similar tax
calculation. Here we can notice the presence of industrial users: a branch of the
aqueduct goes to the fuller of the Ospizio Apostolico of St. Michele, to the state tobacco
manufacture, to colors mills and to the grain mill of Sixtus bridge discharging these
waters in the river. Another part of the water went to a tank under the mills of the
Gianicolo – it must be noticed - after supplying them: as they were state mills, they
were free of charges. On the amount of 1.802 once, only mills employ 370, but also the
remaining water supplied mills, first of all. For the Virgin water a tax calculation of
1789 marks 494 users for an amount of 1.143 once; even the Ripetta mill is considered.
Manufacturers employment grew in time: a report in 1789, assured that the Paola
water moved at that time 6 grain mills with 12 millstones, 2 bran mills, 2 valonia oak
mills, 1 color mill, 1 paper mill, 1 draw iron manufacture and 2 fullers 47. Finally there
were irrigation uses for gardens, cultivation and villas. A visit to Paola water in 1658,
made to evaluate the diversion to Vatican affirms en passant that a lot of water did not
arrive to the fountain of St. Pietro in Montorio but was employed in villas and gardens.
Pipelines were made with clay, lead and sometimes with stone. Scavizzi informs us
precisely about the building techniques, the cost of plastering, welding and binding
operation that were employed for maintenance: but the administrative costs (officers,
taxes, notary) seem to be anyway higher than the cost of installing or modifying a
diversion48.
Although the management throughout the two centuries was precise, at the end of
the 18th century the situation appeared chaotic for the spreading of irregular diversions:
“it is clear enough that a big part of the distribution in spreading the network, failed any
control”49. The water agency was in hard financial difficulties: debts did not allow, of
course, a good technical management. In fact almost 74.000 scudi of the enterprise had
been spent not only for the Trevi fountain (44.833 scudi) and for other artistic works,
but also for building the Gianicolo mills (18.850 scudi) made on commission for Pope
45
See the drawing in P. Scavizzi, La rete idrica, cit., p. 84.
This method was suggested by the “chierico di Camera” mons. Biscia; see the map of the tank of
Montecavallo in P. Scavizzi, La rete idrica, cit., p. 81. It would be important to understand if this
important moment of planning in the management of the hydraulic network was an original innovation or
just a new employ of an ancient roman method, that planned secondary castella both for ruling supply,
both for controlling pressure.
47
Relazione sul condotto dell’acqua Paola ordinata da Monsig. Ill.mo e Rev.mo Giuseppe Vai Presidente
dell’acqua, Roma 1789, f. XII; see C. Cancellieri, L’acquedotto Paolo, mentioned above, who use a
report of the architect Vici of 1789.
48
P. Scavizzi, La rete idrica, cit., tab. p. 88.
49
Ibid., p. 89.
46
13
Innocenzo XI in 1678, and their revenues were taken by the Camera Apostolica. In 1818
the debt was paid and water management in Rome began to work better50.
Finally, when Rome was the Capital City of Italy, the ancient Aqua Marcia was
restored, with the name of Pia water. Also in this case, the structure and function of the
aqueduct were completely different compared to the ancient times: the new aqueduct of
the ending 19th century first employed for Rome a pressure pipeline in cast iron to
overcome differences of level instead of restoring ancient arches51.
4. Secondary streams
Some years ago, working to reconstruct the mill network in the Umbrian Valley
during modern age, I saw some interesting documents; these compared the “Marrana”
stream in Rome to a small regular river, the Clitunno, supplying most of the urban mills
in this valley. The roman technician sent by the Congregazione delle acque to make
peace between the two little towns disputing about the Clitunno water, G. B. Contini,
declared sincerely that “it cannot be found, and I cannot adopt any rule, for justifying
my opinion, and for comparing exactly waters in a plain and regular stream and waters
in a fast flowing one”. For this reason he could only take as an example the experience
in the Marrana stream, as it looked very similar in section, course and outlet52.
It was said before that the Tiber River, supplying energy to floating mills, after
building (or rebuilding) the Gianicolo mills was no longer the only energy resource for
milling in the city. In fact there was another resource, more ancient and maybe more
important, but it was less evident and more widespread: the mill network on secondary
streams, sometimes far from the center of the town, but anyway connected to urban
functions. It must be considered that the land extension of Rome is very wide.
When the Tiber is dry, said the officers of the Congregazione delle acque for shutting
up the Bevagna inhabitants, “Rome itself has to be go for milling its needs in Tivoli”53.
But without arriving in Tivoli, there were other resources nearer to town. Very near: we
saw the Marrana arriving in ancient times to Circo Massimo, under the Aventine hill. In
fact the first channel, not precisely an aqueduct, to be restored in medieval-modern age
was not the Virgin, but the “Mariana” channel, brought in Rome by Pope Callisto II in
1122. It gathered the ancient waters of Tepula and Julia in an open channel starting
from the Valle della Molara near Squarciarelli down to Morena, were the water flew in
subterranean conduit that had been a part of the Aqua Claudia. At Porta Furba it turned
toward Porta St. Giovanni and entered in town at Porta Metronia, arriving at the Circo
50
Ibid.: information is in a report by C. Fea of 1784, published by Scavizzi in app. III. See also: A.
Cambedda, L’Acquedotto Vergine (secc. XVIII-XX), in Il trionfo dell'acqua. Acque e acquedotti a Roma,
cit., pp. 208-213, who mentions documents in Archivio Capitolino, Fondo servizio idraulico, especially b.
132; R. Motta, L’acquedotto Felice, ivi, pp. 220-225, mentioning maps in the Archivio di Stato di Roma
and a map by G. Rainaldi of 1609; D. Cattalini, Acquedotti antichi: vicende e restauri nei documenti
d’archivio, in Il trionfo dell'acqua. Atti del convegno, cit., pp. 73-82, about sources relating maintenance
activities after Rome was the Capital City of Italy, in the Archivio Centrale dello Stato.
51
A. Mastrobuono, Gli acquedotti contemporanei, in Il trionfo dell'acqua. Acque e acquedotti a Roma,
cit., pp. 277 ss.; see the civic proud expressions employed by A. Betocchi, Le acque, cit., pp. 572-573,
both concerning the quality of the water and concerning pressure pipeline techniques using cast iron.
52
Archivio di Stato di Roma, Congregazione delle acque, b. 106, report by G. B. Contini, 18 June 1712.
53
Ivi, b. 234, disposition 8 August 1756.
14
Massimo. Lanciani had very clear in mind that it was an artificial channel of medieval
origins, not an ancient one, and it had nothing to do with the Aqua Cabra54.
The owners of rights upon the Marrana stream were the Laterano basilica, that was at
the time the pope’s residence. In 1723 and in 1856 new springs were flowed in the
channel and in emergency events ( dry periods or the holy year in 1824) water from the
Felice aqueduct was directly diverted in it55. This system was often protected by papal
dispositions until the 19th century56: for instance in 1820 cardinal Camerlengo
Bartolomeo Pacca proclaimed57 that works, derivations and bridges were forbidden if
not previously authorized. Drinking and passing was forbidden for animals, and flaw
cultivation too (in modern age it was particularly polluting); in general, tree cultivation
was forbidden also.
This stream was so regular and important that Dutch engineer Meyer, who arrived in
Rome at the end of 17th century to solve many hydraulic problems in the Papal State,
suggested to make it navigable from the Torre di Mezza Via under the village of Marino
to Porta St. Giovanni. He remarks that bringing a river, or better a channel to outlet in
an harbor is the best way to keep it free from the mud: his proposal was in fact useful
also for maintaining the river harbor in Ripa58.
Route and mills of Marrana are marked, for the part outside the town, in two maps of
the Catasto Alessandrino where we can see its flow and two mills near St. Giovanni
with a “monte del grano” (a deposit of grains) 59. In the 16th century some Spanish
craftsmen controlled the most part of the fullers: an urban market of wool clothes
developed, rich enough to attract capitals60. In some tax reports, made in 1740, 1798,
1821 and 1895 a precise situation is outlined: mills are in different moments 11 or 13,
and their utilization is sometimes changed from grain mills to fullers or specialized
manufactures or back to grain mills. In general, inside the city a grain mill use prevailed
and outside a fuller employment was more frequent61.
Ancient rights of the Laterano basilica were by the time inherited by private owners
gathered in a society. The important role of the Marrana ended when the new banks of
Lungotevere were built, as they stopped the river outlet to the stream: in 1897 Marrana
waters were declared public property and the appeal of ancient owners did not prevent
water use from changing from an energetic to an irrigation use. In 1910 the dispute was
over accepting state property of waters by the owners and granting them waters only for
irrigation uses.
54
G. Bodon, I manufatti idraulici di età romana nella storia e nella cultura antiquaria, in Utilitates
necessaria, cit., p. 21: evidences in 14th century refer of some pipelines near the Coliseum called “forme”
and water basin of Capocce. This "forma Claudiana" or "Lateranensis" is clearly represented in
Dittamondo written and designed in 1447 by Fazio degli Uberti, in the Bibliothéque Nationale in Paris;
see also a Dupérac drawing, ibid. p. 38.
55
M. L. San Martini Barrovecchio, La Marrana o Acqua Mariana, le sue mole e i suoi opifici. Notizie
dell'archivio del Consorzio conservato presso l'Archivio di Stato di Roma, in Gli archivi per la storia
della scienza, Roma, 1995, p. 1282.
56
R. Motta, La decadenza degli antichi acquedotti e la conduzione dell’Acqua Mariana, in Il trionfo
dell'acqua. Acque e acquedotti a Roma, cit., pp. 203-205.
57
Referred in the appendix of M. L. San Martini Barrovecchio, La Marrana, cit. p. 1289.
58
C. Meyer, L'Arte di restituire a Roma la tralasciata navigatione del suo Tevere, Roma 1685, fig. 34.
59
Archivio di Stato di Roma, Catasto Alessandrino, 429/23 e 24.
60
M. Vaquero Piñeiro, Artigiani e botteghe spagnole a Roma nel primo '500, «Rivista storica del Lazio»,
a. III, n° 3 (1995), pp. 99-115, especially pp. 108-111.
61
M. L. San Martini Barrovecchio, La Marrana, cit.; see also R. Lanciani, Le acque, cit., pp. 325-327.
15
Moreover, there were other secondary “Marrane”62. There is a detail in the map that
Gio. Paolo Ferreri drew in 1599 planning a derivation of Tiber River63: the “Amarana”
stream follows the course previously described: the “Acquataccio” stream is the ancient
Almone, that supplies a small lake-basin just before the Appia bridge near Quo Vadis,
where a fuller was placed. In fact there were three fullers: upper, middle (near the
Redicolo temple) and lower (on the Appia street). The Almone stream turned then
toward a St. Paolo fuller64. A fuller of Caffarella valley is mentioned in a document in
1470 and marked in a map of Eufrosino della Volpaia in 154765. During the plague in
1656 these fullers worked as laundries to satisfy hygienic needs of the town in that
moment66. These mills are well evident in the maps of the Catasto Alessandrino some
time later: we can see the Acquataccio course with two fullers67 and more precisely the
fuller of the Tenuta of Caffarella68. As Lanciani remarks, the water of the Nynphaeum
of Egeria was kept in a separate channel to supply alone the medium mill. Lower down
the same stream it supplies energy to a fuller and a “little fuller” on the Ostiense street
near St. Paolo69: they were named after a property (“Tenuta della valchetta”) 70.
In spite of the long use as fullers, these mills were at the beginning grain mills and
then, in the 19th century, were used again as grain mills: they followed, as in the case of
the Marrana of St. Giovanni, the development of the city, sometimes in a commercial
direction, sometimes a demographic growth71.
Finally there was a remarkable spread of mills around the roman land. Some of them
have been studied, as the Pantano72 mills mentioned above: we can see them in the
Catasto Alessandrino on two different but similar maps73. In one of them it is very clear
that they were placed in the falling point where the ancient aqueduct of the Aqua
Alexandriana, now broken, begins. This case could be typical, and similar ones could be
found near the ruins of ancient aqueducts coming from Aniene valley.
These mills of Pantano in particular employed the water of the same spring used
before by the Aqua Alexandriana and after by the Felice aqueduct to supply Rome,
collected in a “rifolta”, a reservoir: the same built by Matteo Bartolani, maybe using a
further structure, to try to raise springs up to the pipeline he built. These mills were
62
Moreover the mentioned streams, also a stream on the left side of the Aniene river is marked as
“Marrana”; it supply a mill in a tower at the Casale del Cervaro, Archivio di Stato di Roma, Catasto
Alessandrino, 430/30.
63
See La valle della Caffarella. Catalogo della mostra (Roma, 14 marzo - 5 aprile 1981), Roma, 1981, p.
85.
64
See the study by S. Ranellucci, made long before these manufactories began to be exploited creating
the Appia Antica Park, in La valle della Caffarella, cit., pp. 121 e 128. He used maps of 18th century in
Archivio di Stato di Roma, Collezione prima disegni e piante, 91/688, 689, 700 e 92/ 717 e 718, e
Catasto Gregoriano, Agro 39; in appendix there are some reports from the Archivio Pallavicini.
65
A. P. Frutaz, Le piante di Roma, Roma 1962, tav. 159.
66
La valle della Caffarella, cit., pp. 139 ss.: there are detailed information in an engraving about the
plague in 1656.
67
Archivio di Stato di Roma, Catasto Alessandrino, 433a/5.
68
Ivi, 433/38.
69
Ivi, 432/I.
70
Ivi, 423/74.
71
La valle della Caffarella, cit., pp. 25-26: at the beginning there is the entire report about the property of
Caffarella in Archivio Centrale delle Stato, Archivio Torlonia. Here there are no maps, but a precise
description of every building including mills, that were then used for milling grains.
72
P. Scavizzi, Nota su tre mulini idraulici da grano: i mulini di Pantano e Valle Marchetta (secc. XVIXIX), «Rivista storica del Lazio», 2 (1994), pp. 205-244.
73
Archivio di Stato di Roma, Catasto Alessandrino, 430/2 e 430/24.
16
owned firstly by the Colonna family, then by the Borghese, who had the rights of
milling (the “privativa”) in the neighboring land: they were a good revenue for the
owners, who had granted also rights to use waters for irrigation.
In 1585 the Camera Apostolica decided that spring water was a public property;
owners had granted the use of only one of the existing mills, to be supplied with the
water raising “inside” the reservoir. From that moment a long dispute began, in which
the pope’s technicians Cornelio Meyer, Luigi Vanvitelli and his substitute Ermenegildo
Sintes were hired. One problem was the installation of another reservoir (“botte”) by the
Camera Apostolica to supply the aqueduct: as this reservoir was connected with the
other, both mills and aqueduct tried to collect the same water. Of course everybody
would like to use the same water to move several wheels of mills and after draw it into
the pipeline; but the pipeline had a certain level, and it could not be lowered without
loosing the slope necessary to bring water in Rome. In fact it was not the quantity of
water to be disputed, but the energy that the initial difference of level supplied.
At the middle of the 18th century the Camera Apostolica reached an agreement with
the Borghese family: a new mill would have been built to replace the old ones, after
which the activity of the old one would be halted if the new one would show that it
worked well. Also milling rights concerning Montecompatri and Monteporzio villages
would go to the new mill. Work was authorized in 1767 and consisted of collecting
water from upper springs, bringing them in Valle Marchetta to a new mill with a big
vertical wheel with boxes, that would produce the same amount of flour than the older
ones (10 rubbia in 24 hours). The new building appeared to the technicians more similar
to an “aristocratic cottage” than to a country mill. But even if it was very expensive its
production revealed to be insufficient to reach the original aim, and the dispute was
finally worked out only when the Camera Apostolica bought it to use it for different
employment. This experience demonstrated that there were limits in the technology of
those times which were not possible to overcome (the diameter of wheels, the structure
of machines). On the other hand, it showed that water which stayed for a long time in a
mill reservoir and passed then in its wheels maybe is not the best water that could be
drawn in an aqueduct.
Finally, a fuller often marked in the maps of the Catasto Alessandrino is St. Pietro’s
fuller, placed on Flaminia Street near Grottarossa on a small stream coming from the
right side into Tiber74. We can then arrive to the sea near Via Ostiense, where we find at
the house and property of St. Lorenza two mills supplied by a secondary stream flowing
into the sea, and near them a “grain deposit on the beach”75; it was not difficult from
this place, with small boats pulled from the beach, to go upstream along the river up to
the city.
5. The right branch of the river at the Tiberine Island
After the walls of Tiber River were built, the existing situation of the Tiberine Island
seems to be a natural scenario. In reality it is not: engineer Canevari, first suggested to
eliminate the island itself closing the right branch and sizing the left one to the rest of
the river bed. Only later did he accept to keep the island by creating an equal section to
both branches, widening in a considerable way the right branch.
74
75
Ivi, 433/IV, 433/7, 14 e 39.
Ivi, 432/20 e 28.
17
In ancient times, and up to modern age, the branch was much narrower than we can
see today. The floating mills beside the island placed in Procopio’s evidence by the
Byzantine general Belisario, were usually on the right branch: this fact confirms its
characteristic of a narrow channel, while the left one was functioning better for
exceeding flow. The left branch would be so prevailing in medieval times to be
navigable, and to allow “galere” built in the shipyard of St. Spirito to leave the
shipyard itself and to get down the river passing left beside the island76.
Other mills that were until 1473 near the ruins of Ponte Sisto were probably placed at
St. Spirito and at the Fiorentini Church when the bridge was restored. The aqueduct
water supplied some mills from above; these mills employed the Tiber only to release
waters (the Ripetta mill, with Virgin water; the Ponte Sisto, with Paola water) 77. In
1563 and in 1575 there were about 20 mills on the urban part of the river78. As clearly
noticed in the comments made in 1744-1745 by Chiesa and Gambarini, the pope’s
engineers79, the riverbed between Ripa and Ripetta harbors was simply an artificial
system of small lakes and streams, functioning as mills and basins. This milling system
worked anyway in a river that looked like a channel: from the Piazza del Popolo down
to Ponte Sisto the houses on the river were built along the ancient Aurelian walls, and
they looked as a unique wall facing the river80. From this point of view the “big banks”
of the Tiber have always existed: they were the compact front of houses or better their
back, because the front was on the main street, opposite the river. Not only the basic
needs of houses were facing the river, but also factories: only when the “big banks”
were built and these activities stopped, the city finally entered a new administrative
and bureaucratic context81.
It must be noticed that the so blamed floating mills were not taken away from the
river up to the banks building. Now, if evidence confirm the existence and importance
of hydraulic mills in the hydraulic network upstream the river, why was the river never
abandoned for milling? I think that non-technical aspects were not considered enough:
the Gianicolo mills were state property; a private willing to gain “industrial” revenue
could anyway be allowed to install a floating mill. Of course a river flood could damage
mills but flour and bread were always sold, differently from other goods: a river mill
revenue touched 10% and was superior to house to let revenues82. Mills’s owners were
city aristocracy, and later religious orders, but already in the 15th century there were
some “capitalistic” efforts83.
76
I. Ait, Un aspetto del salariato a Roma nel XV secolo: la fabrica galearum sulle rive del Tevere (145758), in Cultura e società nell'Italia medievale. Studi per Paolo Brezzi, Studi Storici, fasc. 184-187, Roma
1988.
77
There are many useful images in C. D'Onofrio, Il Tevere, cit.: see the engravings by a Holland
anonymous, beginning of 18th century, of the floating mills at Ponte Rotto (p. 220), and some details by
the Falda plan (pp. 232-233).
78
I. Ait, I mulini e l’Isola Tiberina, Atti del Convegno “Roma e il Tevere. L’Isola Tiberina e il suo
ambiente”, «L’acqua», 3/1999, pp. 61-66; see also U. Mariotti Bianchi, Roma sparita :'I Molini del
Tevere', Roma 1976, expecially for the relationship between river mills and and other mills in Rome, p.
38.
79
A. Chiesa, B. Gambarini, Delle cagioni e dei rimedi delle inondazioni del Tevere, Roma 1746.
80
See the 1879 photograph in C. D'Onofrio, Il Tevere e Roma, Roma 1968, p. 190.
81
R. Sorbello, Il Tevere prima dei muraglioni, in L’Ingegno del Tevere attraverso vicende storiche, valori
ambientali, progetti e risorse inespresse, edited by S. Polci, Roma, Mediocredito, 1996, p. 81.
82
I. Ait, I mulini, cit., p. 63.
83
See the example of Leni family, ibid., p. 66.
18
Now, how did the geographic context changed around the Tiberine Island in the
course of ages? Drilling made recently by the Tiber Watersheds Agency confirm that
the island is a moving sandbank formed by successive layers; its shape has changed in
the time and transformed by the flowing water84. If this is the nature of the island, I
think it is justified made the following hypothesis.
1. The Ponte Rotto was built on the edge where at that time the sand bank ended;
the two branches of the river had then no communication upstream the bridge.
2. The right branch seems to be the partially artificial consolidation of a natural
diversion opened by the river itself during floods. In fact the shape of the island
was artificially protected from the river current transforming it in a stone ship:
the end of this ship was very close to the left bank of the river and forced the
water to go in the right branch85.
3. The existence of the bridge would produce a greater growth of the deposits and
of the dimension of the island itself. By the time the river current eroded the
natural edge, both toward and beside the bridge, separating it from the island and
eliminating the narrow diaphragm between the two branches. The bridge,
abandoned to his fate, would be ruined after the river current, more whirling than
before the elimination of the diaphragm, had undermined its foundations; later its
ruins began a physiologic part of the milling system.
The interaction between the two branches has always been the key to understand and
control the river around the island: it must be considered that actually the strategy to
defend from erosion of the riverbed is centered on artificial thresholds. The latter would
be moving, to allow by adjusting its height to distribute in an equal way the river current
in the two branches, in the same way in which the old dikes of floating mills did to
address more water from the left branch to the right one86.
In other words: we should consider the right branch as a diverted channel or anyway
an artificial maintained channel, more than a natural branch of the river: a way to see
that approach in the case of Rome to the model of urban hydraulic network
6. Future researches and contemporary events
Even if bibliography discussed and documents mentioned seem to confirm the
interpretation suggested, a complete reconstruction of the hydraulic network of Rome
and its territory is still to be done. The many elements cited at the beginning arrived in
time to hide the shape of this network and the evolution of urban function obliterates its
memory.
A necessary instrument of this research is cartography, especially land office maps.
Although urban context appears as an anonymous series of walls and roofs, these maps
can shape the underground circulation of water and the spreading of manufactories
deriving from it87. When a real map of the hydraulic network is not found, it is always
G. Margaritora, S. Magnaldi, L’Isola Tiberina. Introduzione alla idrografia dell'isola, in Atti del
Convegno “Roma e il Tevere”, cit., pp. 11-16.
85
Ibid., fig.2, p. 12 and Falda plan, fig. 3, p. 13; ruins of the “ship” would after obstruct the left branch
maintaining thus the right branch.
86
G. Santariga, Il piano urbanistico di recupero dell'isola Tiberina, in Atti del Convegno “Roma e il
Tevere”, cit. pp. 25-26.
87
Carlo Poni and others practiced a similar approach in the case of Bologna: Paesaggio e strutture
produttive. La città di Bologna e il suo contado in età moderna, in Paesaggio: immagine e realtà,
Catalogo della mostra, Milano 1981.
84
19
possible to use the land office registers (“brogliardi”) to locate the constructions which
use water and the hydraulic branches along which a network is established.
Anyway land office maps in the Papal State at the beginning of the 19th century, the
Catasto Gregoriano, are a precious source for the study of waters in urban context,
because they are always carefully interested in springs, drains, channels, reservoirs.
Surely this is the consequence of a special and long interest of cartography for
hydrographic aspects; maps often remark details which are not marked on the land
register. Maybe the register remarks a “public spring”, or mentions a basin useful for a
garden, but only on the map is it possible to see all visible elements (springs,
aqueducts, drains) of the urban hydraulic system. Special attention must be placed in
these elements: gardens, oil and grain mills, fullers and “cellars”: some researches
suggest that with this name a laboratory is often suggested rather than a stotage for wine
and other goods88. The utilization of waters in the cities of ancien régime is
characterized by many manufactories employing decomposition processes: “technique
requires a lot of water and turn a town in a little Venice, or in the Renaissance in a true
archipelago”89. The consequent sickly situation lasted until the end of the 18th century:
only in the new century soaking is removed and placed outside the town. Then a non
organic chemistry is employed; channels and drains are turned along the city walls and
more and more distant, following the progressive expansion of the city.
The case of Rome is in part more complex for a researcher as the system spread in a
wider territory than other cities in Italy: in these cities the system is entirely enclosed
within the urban walls, or maybe extended to some mill at the nearest stream in the
plain. In Rome instead it is necessary to consider the whole territory (the “Agro”) until
the border of the nearest municipal communities of the Comarca. At this moment only
a complete investigation on the Catasto Alessandrino maps has been done: these maps,
drowned for paying taxes on main roads to Rome, gives proof about the land outside the
city walls. In the next few months, an investigation will be done on maps and registers
of the land office dating from the beginning of the 19th century (Catasto Gregoriano) for
the city inside the walls. Later maps (“Cessato Catasto Rustico”) will provide a
complete and more recent survey on suburban area and the territory of the Agro.
I hope that from the elements exposed there, seems to be a way to see Rome and its
waters separately from the tradition that described the city much more dependent, in
good or bad fortune, to the river as a “natural” element. On the contrary the scenario is
similar to a model of an urban hydraulic system with original characters facing the
ancient one and rather common to many other cities in modern age. The element of this
model are: the character of a system integrating in a whole origin, circulation, functions,
88
See Regolamento sulla misura dei terreni e formazione delle mappe del catasto generale dello Stato
ecclesiastico dall'art 91 del moto proprio de' 6 luglio 1816, Roma, Poggioli 1817. Chapter IV, Del
brogliardo, sez. III, descrizione delle case (pp. 52-53), explains how to conform property denominations:
“La casa abitata dallo stesso proprietario, si dirà, casa di propria abitazione. Se affittata o solita ad
affittarsi, casa d'affitto. Se alla casa vi sono unite botteghe, magazzini etc., casa con botteghe colle
rispettive enumerazioni, specificando se di proprio uso, o affittate [...]. Gli edifici di qualunque genere
con macchine, siano animate a forza di uomini, o animali, siano a forza d'acqua, o di vento, o di
qualunque altra specie, si segnaleranno sotto il nome particolare esprimente il proprio uso”: this
description allow to get out from an anonymous classification every building.
89
A. Guillerme, Les temps de l'eau. La cité, l'eau et les techniques, Champ Vallon, 1983, p. 8.
20
drain of waters; the complete separation of clear waters and dirty waters; the alternate
utilization of waters in domestic and irrigation supply, and for moving mills90.
The ancient water supply system was somewhat different: a roman aqueduct could
supply much more good water than a modern one, but it was a machine working only
with a massive maintenance assured with hundreds of slaves. The restoration of
aqueducts that the popes performed gave up carrying water from the karst mountain,
and so avoided limestone problems. Popes were satisfied with the springs along Via
Collatina (Virgin water), with those from the secondary mountain of the Castelli
Romani (Paola water), and water from the natural volcanic basin of Lake Bracciano
(Paola water). Another difference concerns the importance of energy supply for mills:
although some ancient mills existed in the same place where the popes rebuilt them,
Gianicolo hill, only in the medieval and modern city a system of hydraulic
manufacturers appears. Only in the pope’s city, mills play a key role in the origins and
the development of the hydraulic network.
The case of Rome appears to be in fact a late conforming to the general model of
hydraulic system common in Center Italy. This delay can be explained with several
factors: a scarce population, the nature of urban center devoted to financial and
manufacturers functions, the complex geographic context, the balance with
manufacturers placed outside the city, but whose functions were integrated to the city
economy. Of course, Rome would perform this model in its own way, for the existence
of several different aqueducts, and not one only. In Rome the double and separate
circulation of clear and dirty waters has always been carried out specializing single
aqueducts.
Contemporary events give other evidence about these aspects. The functions of the
Virgin aqueduct remained the same until late 19th century, when extending distribution
obliged to install a raising pump. The expanding city anyway posed new problems, that
the complete rebuilding of this aqueduct in 1936 did not work out. In 1961 its waters,
beside the drinkable waters of the New Virgin aqueduct, were classified not drinkable91.
The same declassing process happened for the Felice water, because of many irregular
derivations: also its waters were classified not drinkable in 1963-68 and were
substituted by the waters of a new Appio-Alessandrino aqueduct. Both these aqueducts
are thus devoted to a mere archeological conservation. Low classification of waters for
the Paolo aqueduct dates much earlier, at its birth, for the decision in 1672 to draw in
Bracciano Lake water. Anyway later events are remarkable. The Paola water remained
not drinkable until some emergencies in water supply (in 1968 and 1979) obliged to
perform treatment installation to make this water drinkable; but then the non drinking
users had to be content by drawing water from the Tiber River in Grottarossa. For these
emergencies a new aqueduct from Bracciano Lake had been prepared92.
90
This model came out from my work about several cities in Umbria: P. Buonora, La Valle Umbra.
Genesi e trasformazione di un sistema idraulico (secoli XVI-XIX). Quaderni monografici of «Proposte e
ricerche», n ° 17/1994; e Id., Il sistema idraulico delle città umbre nel catasto gregoriano, in In primis
una petia terrae. La documentazione catastale nei territori dello Stato Pontificio, Atti del convegno
(Perugia 30 settembre - 2 ottobre 1993), in «Archivi per la storia», a. VIII, n° 1-2 (1995).
91
See also C. Terzano and M. P. Martinico, Acquedotto Vergine: tutela delle sorgenti, in Il trionfo
dell'acqua. Atti del convegno, cit. pp. 249-258. Time and erosion took away the tuff layer protecting the
springs from the surface pollution, obliging to adopt measures in the NPRG (the city planning) and by the
ACEA agency to control damage produced by irregular development of the area.
92
G. De Caterini, L’attuale gestione degli acquedotti Vergine, Paolo e Felice: prospettive future, in Il
trionfo dell'acqua. Atti del convegno, cit., pp. 225-228.
21
Contemporary events confirm also the close connection between domestic supply,
irrigation and energy supply. The civic agency ACEA accepted at its birth in 1937-38
the double traditional employment of aqueduct, for supplying water and energy (now
hydroelectric energy) 93. It must be noticed that the first raising pumps of the New
Virgin aqueduct, in 1901, worked with electric energy produced by the Paola aqueduct;
only in 1930 a new installation was performed to raise waters near the sources of
Salone94. To the big demographic expansion of Rome and to the origins of the civic
agency is connected also the origin of the Peschiera aqueduct, that today supplies 60%
of present needs with waters from the watersheds of Velino Mount. A part of this
system is the hydroelectric installation of Salisano (built in 1937-1940), where since
1980 it joins waters of the Capore aqueduct, after employ in water supply. From this
point two separate pipelines, on the right and on the left side of the Tiber River, arrive
to the several basins in the city95.
The evolution of the water supplying system of Rome in the 20th century poses a
problem: is it the complete realization of the model discussed before or its failure? We
cannot deny that technology suggests very different solutions than the falling
distribution by slope common both in the ancient city and in the modern one. Events
show also that growth, sometimes sudden and dramatic, of demographic context, force
to employ less clear resources than spring waters brought in a pipeline from a long
distance to Rome: lakes, the Tiber River itself. But even if demographic events play
their role, I think in Rome to employ the lake or river water can be considered
historically a secondary resource compared to springs, or an emergency resource due to
demographic crisis, to be overcome. Didn’t the ancient Anio Vetus aqueduct also draw
its waters in the Aniene River?
More generally, we could ask if the case of Rome corresponds to the model outlined
in an interesting book by Dora Crouch about water supply in ancient cities of the
Mediterranean area, strongly dependent on the presence of the karst mountain96. The
Simbruini Mountains whence in time most of the water came to Rome, are a typical
karst mountain. Another model regarding this is the supplying system of the biggest
European cities in rapid demographic growth during modern age, that were far from the
mountain and dependent mostly on a large river97. This different context attracted
attention in the modern world and excited fantasy to find out, in the 16th and 17th
century, inventions to raise water from the river to houses, palaces and gardens of the
city. But everywhere in Europe there have been roman aqueducts: also in these
situations we can ask ourselves how much supplying water and treating water of a river
for drinking is to be considered an emergency, or a physiologic event.
93
About the Azienda Comunale Elettricità ed Acque (ACEA), see S. Battilossi, ACEA di Roma, 19091996: energia e acqua per la capitale, Milano 1997.
94
A. Mastrobuono, Gli acquedotti contemporanei, cited.
95
A. Paglia, Sistema acquedottistico Peschiera-Capore, in Il trionfo dell'acqua. Acque e acquedotti a
Roma, cit., pp. 296-304.
96
D. P. Crouch, Water management in ancient Greek cities, New York - Oxford 1993.
97
For Paris, were since 16th century were employed both pumps for drawing water from the river and
aqueducts for a better supply, see L. Beaumont-Maillet, L'eau a Paris, Paris 1991; for London, C. F.
Antonelli, Acque sporche. Londra e il 'Metropolitan Board of Works', 1855-1865, «Storia Urbana», 61
(1992): in London also the two traditional supply resources were raising water from the Thames and
bringing spring water in aqueducts; about metropolitan cases of late 19th century see finally L. Anderson,,
Fire and disease: the development of Water Supply System in New England, 1870-1900, in Technology
and the rise of networked city in Europe and America, edited by J. A. Tarr and G. Dupuy, Philadelphia
1988.
22
23
Appendix
Pompeo Targone, Discorso sopra i profitti da cavarsi dall’acqua di Bracciano, da C.
D'Onofrio, Acque e fontane, cit., pp. 296-7, note 2.
“… né meno s’averà l’intento, volendo d’una parte di essa far mulini l’uno sotto
l’altro, e l’acqua che s’impiegasse a questo servizio, dovendo venir per terra, e
scoperta per tanto transito, sarebbe soggetta à molte immonditie, et per la caduta
persa inutile all’uso delle fontane. Io ho pensato di proporre alla S.tà di Nostro
Signore un’inventione, con la quale si potrà non solo cavar’il possibile da questa
acqua, vendendola per fontane, ma si potrà con pochissima spesa far un’entrata
perpetua di parecchie migliaia di scudi. Il modo che io propongo è che, condotta
l’acqua alla Porta di San Pancrazio, ivi stando sempre coperta, e non toccando mai
terreno, coll’inventione, che si vede nel mio disegno facci macinare tutta quella
quantità di grano ch’ha bisogno la città di Roma. Doppo che l’acqua haverà
servito questo effetto, restando nella sua stessa purità, senza aver ricevuto
immonditia alcuna, e con caduta più alta di tutte le case di Roma, e ridotta tutta
insieme in una sola botte si venderà a’ particolari per le fontane. E non trovandosi
a vender tutta, d’una parte d’essa si potranno far artifitij per carta, ò da follar i
panni, o macinar mortella etc. che saranno di grandissimo guadagno et à Roma di
moltissima comodità. Oltre questi benefitij suddetti se ne caveranno ancora degli
altri di grandissima importanza. Il primo sarà che dal Tevere si leveranno tutte le
mole, scale e parete ch’impediscono il corso del fiume, e sono in parte causa
dell’inondazione, che ben spesso arreca a questa Città. L’altro sarà che dove hora
per le crescenti del Tevere questa Città patisce del macinare, fatti che saranno
questi molini, in un istesso modo, et in ogni tempo sarà sempre ben servita;
oltreché questi molini non saranno esposti ad esser portati via dal Tevere, né
haveranno bisogno ogni giorno d’esser risarciti, come accade à questo, ch’hora vi
sono, ma con la mia intenzione duraranno molti e molti anni senza bisogno di
cosa alcuna.. Di più essendo tutti questi molini in un corpo, non potranno li
molinari falsificar i grani, e dove adesso vi sono molti Ministri dell’Abondanza
sopra questo effetto, e non possono ben rimediarvi, essendo ciaschun molino
diviso, e lontano dagli altri, all’hora un Ministro solo, ch’assiste in detta fabrica,
senza andar correndo per le strade rimediarà à tutti questi inconvenienti. Quella
parte d’acqua che servirà alle fontane di Belvedere doppo ch’haverà fatto l’effetto,
gli restarà una buona caduta e potrà far macinare un poco de molini ò più, ò meno
la quantità che sarà, e doppo potrà ancor servire alle fontane della Piazza San
Pietro, e di Borgo”.
24