Agricultural and social use of Milan’s water
1. A city born from the waters
The city of Milan lies at the centre of a large, flat region included between the foothill lakes and the Po River, the River Adda forms its eastern border and the River Ticino its western one. The city itself is far from the two main rivers but rich in underground waters and resurgences called fontanili. The natural springs are a phenomenon deriving from the geology of the Po River Plain, which features an area up against the Prealps (upper plain or dry plain), formed by rough materials, sand and gravel, permeable to the surface water which, in turn, feeds a rich aquifer.
While flowing underground in a south-west direction, the fault closest to the surface comes in contact with soil that is progressively richer in less permeable fine materials (silt and clays) and tends to resurface. This area, called resurgence layer, longitudinally crosses the whole so-called ‘padano-veneta’ plain and includes the area of Milan.
Since ancient times, the inhabitants of these lands engaged in a major reclamation endeavor, harnessing these resurgent waters, as well as the smaller water courses and used them in agriculture. One important use of these waters was to make them flow onto the nearby meadows (water-meadows) throughout the year. Their practically constant temperature made it possible to grow grass also in the winter months.
“The ‘resurgence’ is a water source found in the water table which does not appear naturally. Man endeavored to bring to the surface, collect and channel this underground water for irrigation purposes” (Tutela e valorizzazione dei fontanili del territorio lombardo, “Quaderni della Ricerca” 144, marzo 2012).
“In the area of Milan, the current common use of finding and channeling the so-called resurgences for irrigation where there were no rivers or drainage canals, is a practice that dates back to the second half of the XII century. Almost everywhere in the territory of Milan, if you dig reasonably deeply into the soil of the plain, you will find these springs or fountains, formed by springs or pools of water naturally flowing underground”, (Giuseppe Bruschetti, Storia dei progetti e delle opere per l’irrigazione del Milanese, Lugano 1834).
Morphology of the Po river plane and resurgence layer.
From G. Zipoli, La Pianura Padana, storia dell’origine e della sua vegetazione, Milano, 1984.
The resurgence is formed by a fountainhead (i.e. an excavation deep enough to intercept the water-bearimg stratum) and a canal which carries the rising water. In the fountainhead there are springs, also called “eyes” (1-5) from which the water spontaneously flows or comes to the surface trought oak tunes or pipes driven into the ground.
FromIndagine sulle zone umide, Provincia di Milano, Milano 1975.
2. Milan’s Gold
The Vettabbia drainage canal has its source in Milan, south of the historical centre, near what today is Via Mulino delle Armi, underneath Via Santa Croce and Via Vettabbia. This is where the waters from the inner canal ring gathered and flowed into the Vettabbia and continued their course south-east, crossing through the city. Today, the whole canal is covered up and the waters surface only south of Viale Tibaldi. It flows near the locations of Nosedo, Chiaravalle and Viboldone and then into the Lambro River, upstream of Melegnano.
The Vettabbia has been acknowledged as one of the fundamental elements of Milan’s hydrography, the flumen mediolanensis of very ancient origin, whose course was changed several times and whose shapes and roles also changed. In the Roman Age, it was the city’s main emissary, collecting the waters of the Seveso and Olona Rivers. It was navigable and connected the city to the Adriatic Sea through the Lambro and Po Rivers. Its name seems to have come from the Latin Vectabilis, the same etymological root as in words such as “vector (or carrier)” and “vehicle (or carriage)”.
During the Middle Ages, it became the main collector canal of the city’s waste waters and was used for irrigation purposes in a large farmed area of water-meadows, where grazing lands drew great benefit from its “fatty waters”. This system was fundamentally perfected by the monks of the Chiaravalle and Viboldone Abbeys, both founded on the banks of the Vettabbia. The monks “distinguished themselves in promoting irrigation and improving the method” (D. Berra, Dei prati del Basso Milanese detti a marcita, Milano 1822).
The structure and the irrigation function of the Vettabbia canal substantially remained intact until the end of the XIX century, when Milan’s sewage system was built.
Water-meadows are fields used for the production of grass through continuous irrigation obtained by means of a flowing system, especially in the winter months. In general, resurgence water is used because its temperature ranges from 9°C in the winter and 14°C in the summer. This practice provides fresh grass throughout the year (up to 7 harvests with resurgence water and 9 harvests with the Vettabbia’s sewage waters).
The water-meadows originate from the resurgence waters, strictly speaking, there is evidence of their existence as early as in the XII and XIII centuries, although it is believed that they date back to before 1000. Its most evolved structure is the two-wing form, characterized by two folds of slightly sloping soil, at the top of which there is a small canal with an overflow of a veil of water, collected in the lower area by intercapting channels, which, in turn, convey the water to the subsequent field.
The use of the Vettabbia’s waste waters made it possible to deposit their rich fertilizing matter on the soil (nitrogen, phosphorus, potassium): “the best water comes from the nearby resurgences, or from the water from the city’s pipelines, rich in nitrogen matter” (C. Cantù, Storia di Milano e sua Provincia, Milano 1857).
3. Capitalising on used waters
At the end of the XIX century, driven by the Industrial Revolution, Milan’ s population grew very rapidly. From 262,000 inhabitants in 1871, it went up to 481,000 in 1901. In order to control the development of the city and protect the health of its inhabitants, the first City Development Plan was drawn up by engineer Cesare Beruto (1888) and the first Design for the city’s general sewage system was started under the supervision of head engineer of the municipal technical office, Felice Poggi (1890).
The Project envisaged the building of a system of canals, which were not to interfere with the pre-existing network of waterways. The system adopte an unitary criterion designed to collect the waste waters as well as rainwater (tout-à-l’égout) and it was to work by gravity by exploiting the natural slope of the soil. The considerable amount of waste waters produced by the growing expansion of the urban area, was to be disposed of in the water-meadows located south of the city, irrigated by the Vettabbia Canal, which had collected Milan’s waste waters since the Middle Ages.
That this was the right choice was proved by a number of physical, chemical and bacteriological studies carried out by several municipal Commissions. They were to monitor the effectiveness in treating the waters and the level of health and hygiene safety in the course of the next decades.
In order to make the system compatible with the progressive population growth, the agricultural area designated for the disposal of the waste waters was expanded. The hydraulic system of the Vettabbia Canal was duly adapted through the involvement of the farmers, members of the Consortium of the Users of the Vettabbia Canal, with whom a series of agreements were drawn up (1889, 1905).
This approach to treating the waters for agricultural purposes was used until the first decades of the second post-war period, when urban development and the ensuing shrinkage of the disposal areas, besides industrial wastes, made its ancient processing potential ineffective.
4. The rediscovery of the agricultural use of used waters
Since the Sixties of the last century the water-meadow system appeared as completely overcome by pollution, population growth and the urban sprawl. All the conditions made it necessary for Milan to find a new solution. In 2004, urged by the European Community, the city installed a general overall system for the processing of waste waters, which allowed to re-use about 90% of its waste waters in agriculture after they had been treated and made suitable for this purpose by two plants using the same processing system located in Milano San Rocco and Milano Nosedo. The remainder of the city’s waste waters was treated by the plant at Peschiera Borromeo, which conveys them to the northern section of the Lambro River.
Of the three treatment plants, all of which are south of the city, San Rocco collects the waters from the western area of Milan (about 112 sq. km, including Settimo Milanese, green), while Nosedo collects the waters from the central-western area (69 sq. km, pink) and the waters from the eastern area (22,3 sq. km. yellow) are conveyed to the second line of the treatment plant at Peschiera Borromeo.
Re-use in agriculture of the waters treated in the Nosedo and San Rocco plants, today provides a technologically advanced way recreate the urban water cycle once carried out by the water-meadows.
|San Rocco||Nosedo||Peschiera Borromeo|
|Ordinary capacity [cu.m/s]||4,00||5,00||1,10|
|Maximum capacity [cu.m/s]||12,00||15,00||3,30|
* By “inhabitant equivalent” we mean the organic biodegradable load produced in one day by a person, equal to the requirement of 60 grams of oxygen per day (European Directive 91/27/EEC).
5. Waters and society
The photos collected in this section, testify to the strong link that a big city like Milan has always had with its waters and, through them, with its territory, until very recent times. These images clearly show an urban fabric deeply impacted on by the multiple use of its surface and underground waters.
Milan’s historical canals (the so-called Navigli), developed in the Middle Ages, were not only waterways for carrying heavy goods and irrigating fields, vegetable gardens and rice paddies; on their banks there were dozens of washing stations and, on holidays, they were the backdrop for many happy reunions, fishing competitions and boating or cycling trips on the high banks used for hauling the barges. The canals in the city itself, offered popular swimming areas in the summer, such as the Argelati Baths at Porta Genova or, more refined locations like Diana Baths near the Porta Venezia city walls.
This balance of functions was to disappear as the growth of urbanization and industrial development took over. Although, at the 19th–century harbor at Porta Ticinese (Darsena), some barges could still be seen unloading sand and building materials in the 1960’s, the lack of a new industrial port south of the city and modern waterway connections prevented navigation on the “Navigli” to face the competition of railway transport first and road transport later.
As early as 1928, the oldest ‘naviglio’, the internal canal ring that ran for almost five kilometers around the city centre, the very heart of the continuity of navigation between the Ticino and the Adda rivers, was declassed, covered up and turned into a ring road for motor traffic. This was the symbol of forgetfulness destined to last until the beginning of the new Millennium. Recently, the citizens of Milan showed their renewed interest in recovering the city’s waterways. Proofs of this are the popularity of the banks of the canals as a strolling area, both in the city and in the outskirts, the resauration of the Darsena in the occasion of Expo Milan 2015 and the results of a city referendum in 2011 for the and re-opening of the internal canal ring.
6. From the ‘Navigli’ to Milan’s Sea
At the end of the Twenties, driven by the fervor of urban change that led to the covering up of the internal canal ring in Milan, a grand new public hydraulic project developed in the fields East of Milan: the ‘Idroscalo’. It consisted of a large artificial lake, fed by the groundwater table and designed to be a polyfunctional infrastructure: a port for hydroplanes and a place for nautical sports, fishing, swimming and leisure.
Located a little more than seven kilometers from Piazza del Duomo and close to the factories of the aeronautical company Giovanni Caproni inside the Aerodromo di Taliedo, Milan’s Idroscalo was the only project of this kind to be developed in the country, pursuant to a 1927 Act which made it mandatory for Provincial Administrations to arrange for emergency landing areas for hydroplanes.
In that years nonetheless, these aircraft were drastically reduced and replaced by terrestrial airplanes, which led such locations to be used mainly for sports and swimming. Idroscalo was opened officially by the competitions of the Littorali del Remo in 1934. Four years later, it hosted the European Rowing Championships and on its shores a very popular bathing resort developed and became the holiday resort for those who couldn’t afford holidays on the Adriatic coast in such places as Rimini. It became “Milan’s Sea”.
“Mare di Milano, Riviera o Parco Azzurro, l’Idroscalo di Milano dimostra attraverso l’abbondanza dei suoi soprannomi che cosa significa per la capitale lombarda. È una facile aspirazione, un piccolo sogno a portata di mano, pronto a farsi realtà per una popolazione che ama disperatamente l’acqua e non può accontentarsi di quella ancora visibile – e non troppo invitante – dei Navigli” (Luciano Visintin, in Il Parco Idroscalo, a cura di Alessandro Credali, Giuseppe Garra, Provincia di Milano, Milano 1999, p. 54).