Although known the world over as one of the most romantic places on earth, Venice remains a fully functioning urban space, with all the associated needs of a city. While the picturesque bridges and canals do serve an important purpose in the transportation network, it is the virtually unknown network of public utilities that truly keep Venice alive. Buried within the layer of sand and clay beneath the paving stones of the streets and bridges lies a complex network of pipes and wires which support the transportation of resources vital for modern living.

Like all other modern cities, new utilities have been installed in Venice as they became available in order to replace old and outdated systems. Currently, the mostly widely used utilities within the city are natural gas, water, electricity, and sewage, together allowing for heating, cooking, indoor plumbing, lighting, electronic appliances and many other modern conveniences. Additionally, Venice also has telephone and data lines, as well as a new fire fighting network.

Also similar to all other cities, Venice’s utility network requires constant preventative maintenance and emergency repairs. What makes this process unique is the large percentage of the city protected by federal and local law as historical regions. In these areas, painstaking efforts must be made in order to leave the city looking exactly the way it did before construction began. Any changes that do get made to the appearance of the city must first be approved by one of the two custodians of the city, called the Superintendenzia, by means of a long application process oftentimes ending in disappointment for the applicants. As a result of these laws, new construction only occurs when it is essential to the survival of the city, making it difficult for new utilities, such as an upgraded sewer system, to be implemented.

Streets The belief that the Venetian canals completely surround every building is a common misconception held by those who have not seen the city. In fact, only a small percent of the buildings have one or more sides abutting a canal. The reality is that the city is composed of many large islands, some housing hundreds of buildings. As a result, the city does, in fact, have a complex network of streets and alleyways. These pathways serve as the core of the pedestrian transportation system and many different types can be found though out Venice.

Figure 3: Fondamente, which run parallel to canals, are the type of street most associated with Venice. Many believe that the every building in the city is surrounded by water with only the fondamente allowing for pedestrian transportation.

Figure 4: In actuality, many of the streets of Venice are actually calle, such as the one shown above. These are the streets found on the interior of the islands. Many of the major paths through the city follow calle and other land locked routes.

Figure 5: Among several other minor types of streets, the sotoportegi is one of the most interesting. Since land on islands is so valuable, several buildings were constructed over existing pathways resulting in tunnels called sotoportegi

In addition to the various types of streets, there are also several different types of building materials used to construct those walkways.

stone block cobble stone brick asphalt

Contents 1 Gas 2 Water 3 Electricity 4 Sewer 5 Repair Work 6 Future 7 References

Gas

In the 1840’s Venice installed its first gas network for the purpose of public lighting. This system carried a gas produced from coke to lanterns throughout the city. This altars which were originally installed in areas where the light from the altar’s candles would illuminate important walkways. A century later, the system was converted to the methane that is still used toady and was expanded to allow citizens the option of paying to bring gas directly into their homes. This upgraded system made Venice one of the first cities in the world with publicly available natural gas.

As houses began to convert, gas began to replace wood and oil as a means for cooking and heating; however, not everyone was willing to change. During the flood of 1966, oil tanks throughout the city spilled into the water damaging buildings and canals. This resulted in the Venetian government imposing a mandatory conversion to gas throughout the 1970’s and 1980’s. Today 178 kilometers of piping, controlled by Vesta, Enel, and Eni S.p.A., supply gas to over fifty-five thousand inhabitants of the city.

Water

Note: This section currently contains insufficient amounts of information. Further interviews and better translations of existing materials are required before this section can be considered for publication. Originally, Venice relied on sand-filtered well water. These wells were maintained by several different guilds. One guild was responsible for creating the wells while others specialized in cleaning them while yet another guild would carry water in from the mainland during times of drought. Unfortunately, many of the wells became contaminated with disease and industrial pollutions. Seeing the inevitable failure of the well system, Venice constructed an aquifer to carry fresh mountain spring water into the city.

Electricity

Note: There is currently no information available for this section. Further interviews and better translations of existing materials are required before this section can be written.

Sewer

The Venetian sewer system is like no other in the world. Unlike other medieval cities where chamber pots were emptied out the windows creating an unsightly and unsanitary mess on the streets, Venice’s canals provided an easy method for disposing of household waste and having it wash out to sea with the tides. Even for the landlocked houses, only a short length of pipe was needed for quick disposal. As a result, Venice developed the first sewer system to be implemented in the world. The city’s unique gravity driven system called the fognature consists of three parts and relies heavily on the tides .

Similar to modern in-ground systems found on buildings in rural areas, the first part of the system is the sedimentation tanks. These tanks are built into the foundations of the houses and collect the black and grey water from sinks, toilets, showers, and other devices. The solids then settle to the bottom of the tank while the liquid is decanted off the top. More complex systems can consist of several sedimentation tanks in series to further separate the solids. Also similar to modern in-ground systems, the tanks occasionally fill with solids and must be emptied.

From the sediment tanks, sewage flows through the collettori which underground channels made of brick. The channels are inclined to induce the flow of liquid in the appropriate direction. The collettori from each house usually flows into a major collettori which then transports the waste towards the perimeter of the island.

On the perimeter of the islands, sbocchi—sewer outlets—interface the collettori with the canals, depositing the sewage directly into the water. The sbocchi were originally located 1.8 meters below the zero sea level in order to ensure that they would remain below the lowest low tide level. During more recent repairs, the sbocchi were rebuilt higher than the originals at 1.3 meters and, most recently, at 0.8 meters. However, since the zero sea levels are also rising, the outlets are still located below the low tide mark. Once the sewage is discharged into the canals, the system is dependant on the tides to carry the material from the city out to sea. Overall, it is estimated that 12% of the sediment that accumulates in the canals results from sewage disposal.

Repair Work

Like systems in all other cities, the Venetian utilities require constant maintenance which can come in one of two forms: preventative maintenance or emergency repairs.

During the current round of preventative maintenance, the city is performing two tasks. The first is called “rationalizing” the network. Because each utility was added separately as new technology became available, the pipes and wires were installed one on top of the other with no attention to organization. To “rationalize” the system, the pipes are being rerouted to form a more organized network. In the process, old pipes and fittings are also replaced and all the elements of the networks are being catalogued in Global Information System map layers. The second task performed in some areas after rationalizing the network is to raise the pavements that cover the utilities. This process is necessary to prevent flooding in areas where the previous pavement height was below the standard high tide mark. When pavements are reinstalled, extra base material is used beneath them to raise them above this mark when possible. In some locations, the actual height increase is limited by the height of doors along the street.

For emergency repairs, the city uses a call in service named MIMUV. With this service, residents can call to report damaged or malfunctioning pieces of infrastructure within the city. An inspector is then sent to verify the report and can then order repair work to be done. MIMUV keeps track of all progress made on each report through out the repair process.

Future

While the majority of the streets and utilities within Venice are in good condition, the sewer system has become outdated and inadequate. The current sewer system presents both a health hazard and a physical threat to the city.

By directly depositing sewage into the canals, the sewer system contaminates the water with bacteria such as salmonella that are hazardous to humans . While this was more sanitary than the other methods of disposal in its early days, health standards have since increased and Venice has fallen behind the rest of the world. In an attempt to modernize the sewage system, the city has recently required that all hotels, restaurants, and other businesses with facilities install mini treatment facilities which process the sewage before it is deposited into the canal. Additionally over 100 other mini treatment stations have been installed throughout the city. These devices intercept sewage flowing in the collettori and process it before it is discharged into the water. However, despite these efforts, a large percentage of residential systems still connect directly to the canals.

In addition to the health hazards, this system can also be destructive to the city. Despite the sediment tanks, some solids inevitably escape containment and are deposited in the canal. In addition to crumbling masonry, trash, and particles carried in by the tides, the solids collect on the bottom of the canals forming layers of sediment. During periods such as from the 1960’s until the 1990’s when no maintenance was performed on the canals, the level of the sediment increased until it began to block the sbocchi. When this occurred, pressure built up within the collettori until the structural integrity of the mortar holding the bricks together was compromised. The pressurized sewage was then able to escape by finding new pathways through the fractured mortar into the canals. The weakened mortar became incapable of holding the stones together and large holes around the sbocchi began to develop throughout the city. During the ongoing repairs, sediment is removed and damaged sewers and canals walls are repaired, but nothing is been done to fix the core of the problem.

In 1999, a student research team concluded that approximately 12% of the yearly sediment results from the direct disposal of sewage into the canals. Additionally, crumbling masonry contributes 6% of the sediment while the remaining 82% comes from unknown sources which could include debries carried into the city by the tides. These team was also the first to correlate localized canal wall damage to blocked sewer outlets .

In 1998, a team of researchers investigated the potential for installing a HIFLO vacuum sewage system within the city. This special type of vacuum sewage system is specifically designed to handle the high volumes of sewage that are produced in high density areas of cities. The team determined three different methods of installing the system each with different benefits and drawbacks. These proposals are currently among the options being considered by the Venetian government for upgrading the city’s sewer system .

Without continuous, costly maintenance , this system will once again fall into disrepair and begin destroying the city. Even with maintenance, the canals are polluted with biological waste that not only results in an unpleasant odor, but also has the potential of transmitting diseases. Currently, the only known way to remedy the issues related to the fognature is to replace it with a more modern system. Since the city is so close to sea level, leaching fields are impractical so a collection facility is required. Unfortunately, the limited elevation differences between the houses and the collection facility eliminate the possibility of a conventional gravity driven system. Instead a vacuum sewage system, which uses pressure differences to pull the sewage through pipes, would be required. At the time of this writing, Venetian officials are pursuing several different methods of implementing this type of system within the various districts of the city; however, limited funding and reluctance to modify the historic sections of the city have greatly slowed the process. The installation of the gas, water, and electric utility networks within the city have proven that the city is not unwilling to add modern amenities: hopefully, it will just be a matter of time before the problems with the sewer system are remedied.

References

Borrelli, Alexander P., Matthew J. Crawfod, James W. HOrstick, and Izzettin Halil Ozbas. Quantification of Sediment Sources in the City of Venice, Italy. Worcester Polytechnic Institute: Worcester, MA, 1999. Henceforth referred to as Borrelli, Sediment. Clark, CS. “Potential and Actual Biological Related Health Risks of Wastewater Industry Employment.” Water Pollution Control Federation Journal 59.n12 (1987): 999-1008. Felices, Martin, Lauren Goodfellow, Jay Johnston, and Sonali Maheshwary. A Preliminary Feasibility Study of a HIFLO Vacuum Sewage System within the city of Venice, Italy. Worcester Polytechnic Institute: Worcester, MA, 1997. Henceforth referred to as Felices, HIFLO System.