Introduction
Rome has a long history of advancing civil engineering by building greater public works than what had been done before such as grand structures and conveyance networks. The Colosseum, Pantheon, and aqueduct arcades all stand as testaments to that. Grading, utilities, and pipe networks are essential tasks of civil engineers in site development. The creation of aqueducts through tunnels, arcades, arches, and siphons, brought water to ancient Rome. This great volume of water carried at the highest elevation possible allowed for innovations in how water finally reached the people. Going beyond cisterns and wells, instead making lead pipe networks and fountains. These were gravity-fed systems that did not require any electricity or pumps. These practices created a lasting culture of bringing water to the people of Rome. It is this history that led to the installation of Nasoni throughout Rome in the 1800s. This came at a time when most people still didn’t have plumbing in their homes. There aren’t as many Nasoni now as there were at their peak due to people having plumbing with drinkable water in their homes but there are still thousands with more added at historic sites with many visiting tourists.
Background
The Nasone is a continuously flowing drinking fountain. They are cast iron columns that stand about a meter tall with a single narrow pipe that comes out about halfway up the cylinder and then bends down with two spouts. Water continuously flows out of the main spout, and down into a drain located at the base of the Nasone. The name Nasone means big nose in Italian, this name was given due to the characteristic shape of the pipe bending out of the cylinder. They typically stand independently, often on the side of a street by a wall or at the end of a plaza or public square. An example of the typical Nasone can be found in Figure 1.
Figure 1: A typical Nasone found in Rome
The constantly running fountains can be used to refill water bottles, buckets and more but there is a secondary spout, a smaller hole along the top of the primary spout tube. By plugging the primary spout, water will instead spring out of the secondary spout to allow for easier drinking. This is demonstrated in Figure 2.
Figure 2: Water flowing out of the secondary spout
This allows for drinking by bending over the arching stream shoot upwards out of the secondary spout when without a container. This allows water to shot up and out over a varying distance dependending on how plugged the main spout is by the user.
Fountains that are not continuously flowing are rare to find in Rome. Most are located outside of the heart of Rome, away from the densely populated regions. Some of these fountains require the twist of a valve or the press of a button to activate. An example of a fountain that requires a button press for water to flow can be seen in figure 3.
Figure 3: A fountain that require a button press outside of Catacombe Di San Callisto
The experience of these fountains is very different from the United States and University of Washington campus. In the U.S. water is often provided freely in many business and restaurants but public drinking fountains are often not found outside. Water fountains in the U.S. are located by public restrooms inside buildings or facilities at parks and restaurants serve pitches of ice water endlessly. The U.W. campus has many fountains in every building but the design is very different. They are typically installed into an inside wall, requiring a button press and have a sensor for bottle refills and an electric counter to track how many bottles have been refilled. In contrast, many buildings in Italy do not have water fountains, and restaurant all charge for water which comes in bottles, either still or sparkling. Ice is not provided. Instead there are the Nasoni, all of them being located outdoors. There is a different culture of water but it was very useful on very hot days doing outdoor tours for Engineering Rome 2024 to have water nearby.
History
In antiquity water wells and cisterns water holding tanks were used for getting water. Wells work by digging a shaft into the ground until reaching an underground spring or groundwater and then using a bucket and pulley to bring water to the surface. Cisterns were large chambers for collecting rain water and holding it in reservoir (Angelikis, 2012). Aqueducts were able to bring water in Rome in vastly greater quantities than any other method before it which led to the creation of fountains. The large quanitities of water coming in under a gravity system at the highest elevation possible could then be used in pressure systems using underground pipes. The greater the depth of water in tank, the greater the pressure it creates due to its weight from gravity. Nasoni began to be installed in 1872. Mayor of Rome, Luigi Pianciani set forthe the initiative during the 1870s to install them (Mauro, 1999). They reached a peak quantity of 5,000. Now they number around 2,500 as homes have access to drinking water (Angelikis, 2012).
The original Nasone design was more intricate with three pipe outflows, each ninety degrees from the other, being on three faces of the main cylinder. The spouts took the shape of dragons, or other creatures. Some also had bowls at the bases before the water reached the drains for animals to drink from. A remaining example of one these original Nasone can be found in figure 4 located by the Pantheon.
Figure 4: Original Nasone Design
Nasone have been simplified to a standard cylinder and a single pipe outflow. There do remain exceptions to this standard design though. In some places there are drinking fountains affixed within a wall, in an alcove with a sink basin rather than a floor drain. In other places there are decorative fountains that have drinkable waterspouts such as Barcaccia fountain at the base of the Spanish steps or the Lover’s fountain at the Trevi fountain which can be seen in Appendix B. These are rare and atypical designs. Most decorative fountains do not use potable water. Nasoni are found outside of Rome as well across Italy with more variations in their design. A map of the Nasoni around the University of Washington Rome Center can be found in figure 5.
Figure 5: Map of Nasoni around UW Rome Center
Topics Covered
The focus of this paper will be on the function, design, hydrology and maintenance of the Nasoni. Various sites were visited throughout Italy to observe Nasone, collect data and produce calculations from the information gathered. Information such as dimensions to flow rate were either researched, measured or calculated for the purpose of this paper.
Nasoni Analysized
Function
Some of the pipes inside the Nasone can be seen in Figure 6. Unfortunately the information on the inner workings of the Nasone is limited to what can be observed on site.
Figure 6: A view of the inside of a nasone
The Nasone taps the drinking water line pipes, then water flows through the pipes inside of the Nasone and flows out of the spout. Whenever there are leaks, there are holes on the outside of the Nasone to allow the water to release water and pressure from the pipes and body of the fountain. This can be seen in figure 7.
Figure 7: Nasone overflow drain
Design
The Nasone has gone from the three outflows to a single outflow over the years but still function the same. All of the physical design variations examples found inside and outside of Rome during Engineering Rome 2024 can be found in Appendix A. Most of the water in Rome arrives by the Peschiera-Capore aqueduct or aqua Paulo-Traiano, which gets settled and filtered to then be distributed throughout the city by pipes (Stefanie, 2022). Then some of these pipes connect to the Nasoni throughout the city. An external schematic diagram of a Nasone can be seen in figure 8.
Figure 8: Schematic of a Nasone (Wikipedia.org, 2009)
Since the water is always flowing, this reduces the chance of any build up in the pipes from still water such as bacteria, helping to keep the water sanitary. Access to clean and cold drinking water is essential for public health in a densly populated region that expieriences a hot summer climate. Dehyrdation and heat stoke are very dangerous during the hot summer weather but the water from the Nasone is always flowing and a cool temperature. Even homeless populations and animals are able to enjoy these water supplies.
Hydrology
The flow rate out of the main spout of the Nasone is 5.5610-5m3s. This was found by measuring the time it took to fill a 0.5 L bottle which was 9 seconds. In other words it would take 18 seconds to fill 1 L. The diameter of the pipe was measured to be 0.01 meters and the cross sectional area was calculate to be 7.8510-5m2. The velocity of the water coming out of the spout was found to be 0.71ms. This was calculated using the measured flow rate and area of the pipe.
A=d24
=0.012[m]4
=7.8510-5m2
v=QA
=5.5610-5[m3s]7.8510-5[m2]
=0.71ms
The diameter of the smaller hole was measured to be 0.004 meters and the cross sectional area was calculate to be 1.2610-5m2. The flow rate out of the smaller secondary spout of the nasone is 3.1310-5m3s as it took 16 seconds to fill a 0.5 L bottle. The velocity of the secondary spout was found to be ms. This was found using the same equations. and checked by another property of fluid mechanics.
A=D24
=0.0042[m]4
=1.2610-5m2
v=QA
=3.1310-5[m3s]1.2610-5[m2]
=2.48ms
The water in the Nasone is always flowing but how laminar or turbulent the flow can be determined. This is based upon the Reynolds number which can be found from the flow rate, diameter of the pipe, cross sectional area of the pipe, and the kinematic viscosity of the fluid. The kinematic viscosity is assumed to be 1.3110-6m2s (engineering toolbox) as the water is assumed to be 10℃ (Rome and Beyond). From these values the Reynolds number was calculated.
Re = QD/vA
=5.5610-5[m3s]0.02[m]1.3110-6[m2s]3.1410-4[m2]
=2,703
Since any number above 2000 is turbulent flow this shows that the flow immediately out of the pipe is not smooth flow but turbulent. The water coming out though is not very turbulent which still allows for a pleasant user experience as the water is not shooting out at too high of a velocity.
Gravity-based fountains use principles of physics to create spouts of water that can shoot straight up to great heights. In ancient Rome, the water from the aqueducts would flow into castellums which were ancient settling tanks. This would slow the velocity of the water, allowing impurities to settle in the bottom of the tanks (Dembskey, 2009). The ancient pipes then flowed out of these castellums across the city. The depth of the water in the castellum created the hydrostatic pressure. This pressure is a result of the density of the fluid, the force of gravity and the depth of the fluid.
P=gh
The pipes can be considered a closed system, meaning pressure and velocity are conserved throughout the pipes. Bernoulli’s equation can be used to find how high the water can shoot up against gravity at the outflow.
constant=gz+v22+P
The key concept is change in elevation, as long as the water at the fountain is coming out at a point lower than where the water entered the pipes there would be energy for the water to come up again (Hunter, 2023). Work can be done on the system to bring water from underground pipes back up to surface following the hydraulic gradient line (HowStuffWorks.com, 2024). Another key concept is the continuity of flow as this relates pipe diameter and velocity. When water flowing in a pipe changes to a narrower pipe the velocity of the flow increases whereas if the diameter of the pipe increases the velocity of the flow decreases. Knowing the principle of continuity in fluid mechanics, flow remains constant in a closed system. The velocity out of the smaller spout must be greater due to the smaller opening since the flow remains constant and the change in area is inversely proportional to the change in velocity.
Q=v1A1=v2A2
This means that when the spout at the end of the fountain is narrow than the pipe before, the water will shoot out with greater energy or in other words, at a greater velocity. This is part of how water can shoot straight up out of a decorative fountain for an impressive display but is also a key factor in controlling the flow out of a drinking fountain to make it usable for people. Thus, when the main spout of the Nasone is plugged, the water will shoot up and out of the smaller spout, following the principles of projectile motion. This allows a person to not have to bend down very far to drink directly from a Nasone. The water shoots out in a graceful arc of a parabolic path.
The principles of projectile motion can be used to determine the maximum height and distance the water will reach when coming out of the secondary spout. Gravity is assumed to be -10 ms2 and the angle of the water to be approximately 45° out of the smaller spout for the purpose of these calculations. The water reaches a peak of 0.77 meters above the ground and shoots out 1 meter. It was observed that horizontal distance the water reached caught many people off guard as many didn’t anitcipate how far the water would shoot when fully plugging the main spout.
vix=vcos
=2.48[ms]cos(45)
=1.75ms
viy=vsin
=2.48[ms]sin(45)
=1.75ms
vf=vi+gt
0=1.75[ms]-10[ms2]t
t=0.175s
yf=yi+viyt+gt22
=0.62[m]+1.75[ms]0.175[s]+-10 [ms2]0.1752[s]2
=0.77m
0=0.62[m]+1.75[ms]t+-10 [ms2]t22
t=0.57s
xf=xi+vixt
=0+1.75[ms]0.57[s]
=1m
Some assumptions must be made based upon the information available. The design of the internal mechanics of the Nasoni are proprietary information not readily available to the public. Simplifications were made for the purpose of the calculations of flow, velocity and distances of the water. These include the temperature of the water, the pipes being perfectly smooth, the gravity constant was rounded up, and most numbers were rounded to three significant digits or less for simplicity. Due to time constraints, data collected for calculations were done from a single Nasone so if there are variations from one Nasone to another it is unaccounted for. It is a fair assumption though that the design intention would be to give as consistent of an experience as possible across all Nasoni. Data was collected by the Trastevere region in September of 2024. The Nasone can be found on the map in figure 9.
Figure 9: Map location of the Nasone used for data collection
Maintenance
To ensure water quality, tests are done all over Rome frequently to ensure that the water is safe for the public. Bringing clean water to Rome is essential but getting it to people is a whole other journey. The distribution of water in the city is done through the pipe networks. Nasoni are still made and maintained by ACEA. They recently installed several more by the Colosseum and Roman Forum. They also introduced new water stations that have dispensers for regular still water, and sparkling water and chargers for electronic devices (Acea, 2024). One of these stations can be seen in figure 10.
Figure 10: Acea water and power station
A group from Acea called Waidy, created an app in 2019 called AceaWaidyWOW to map out the locations of all of the Nasoni. It takes user inputs such as proposed names and photos submitted by user to better identify the Nasoni on the map and when selecting a specific Nasone. Users can also submit reports in the apps if there are any issues at a Nasone to help Acea stay on top of maintenance and know where issues arise. Users can also see reports on the quality of water coming from the Nasone (Waidy, 2024). Various Nasoni had QR codes installed above the spout so people can scan them with their smart phones when getting water. This code links to the AceaWaidyWow app so people can locate other Nasoni. A Nasone with a QR code can be seen in figure 11.
Figure 11: Nasone with QR code for Nasoni map app download
Conclusion
Nasoni serve as a prime example of civil engineering in Rome, delivering drinking water to the people. This evolution of water delivery continues to be innovated upon, following a rich history starting with the aqueducts to the latest water and recharge stations by the Colosseum.
Thanks to the aqueducts in use to this day, water continuously flows out of the Nasoni across Rome. The Nasoni have been around for over 100 years. Water flows out of the main spout at velocity of 0.71ms and a flow rate of 0.06Ls from the 1cm diameter opening. Water can shoot up to 0.77 meters in the air and 1 meter out from the secondary spout when the primary is fully closed. Whether Nasoni use a gravity system is not known but if so they would follow the system of ancient Rome that use elevated water tanks to create water pressure in the pipes to push water out of the fountains at lower elevations, otherwise a pump could be used. The Nasoni can be found using an app and are maintained by Acea. The fountains are continuously monitored for water quality and the continuous flow helps prevent the build of contanimants in the water.
Further studies could be done at other sites and during different seasons to see how consistent these results are. It is undetermined how much the seasons impact the flow rate of the Nasoni or if there is much variation across different locations. As it stands, the Nasoni are very functional water fountains that serve their community well that highlights the impact of civil engineering in Rome.
Bibliography
Acea Group. (2022, August 17). Nasoni, the typical water fountains of Rome – acea group.
Nasoni, the typical water fountains of Rome – Acea Group.
Angelakis, A. N., Mays, L. W., Koutsoyiannis, D., & Mamassis, N. (2012). 17.3.3 Water
Services in Present-Day Rome. In Evolution of Water Supply Through the Millennia (pp.
459–461). essay, IWA Publishing.
Contributors, HowStuffWorks. com. (2024, March 12). How did public fountains, like those in
Rome, work without any type of motor to pump the water?. HowStuffWorks Science.
Dembskey, E. J. (2009, February). The Aqueducts of Ancient Rome.
Hunter, E. (2023, March 14). How did fountains work in Ancient Rome? – ancient rome. Explore
the Past, Enrich the Future.
Ray, C. C. (2015, January 19). Electricity-free fountains. The New York Times.
Stefanie. (2022, February 9). Nasoni: All about water fountains in rome – rome and beyond.
Rome and Beyond.
Appendix
- Gallery of Nasoni
Rome Nasone
Rome Nasone
Parco Savello – Giardino degli Aranci, Nasone
- Non Nasoni drinking fountains
Biacenna Fountian, Spanish Steps, Rome
- Nasoni outside of Rome
Nasone, Venice, Italy
Nasone, Milan, Italy
Nasone, Tivoli, Italy
Nasone, Varenna, Italy
Tristan Songer
Cameron Stuart
Josie Noone
Cecilia Bailey
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