Heyooooo this is right up my alley.

Milanese hydrography is one of my absolute favorite topics, precisely because of the cyclopic scale of the public works that, over numerous centuries, made the Milanese landscape a man-made marvel of engineering. We might not a "marvel" at Milanese waterworks as we marvel at Egyptian pyramids or the Roman colosseum, but they nonetheless represent a fascinating example of how human beings can shape the environment around them.

Although the entirely of Northern Italy's hydrography could be examined, much of of it was ruled by the Milanese state at one point or other, and the landscape is fairly consistently characterized by waterways flowing straight down from the Alps to the basin of the River Po. Thus I will mostly focus on Milan as a representative example; although it's also worth pointing out that the details around Venetian hydrography are somewhat different and equally interesting, especially after the Republic came to govern the whole of Northeastern Italy and founded a government office, the Magistratura delle Acque, to manage inland navigation.

When the Romans first arrived in Milan between the third and second centuries B.C.E. they found a hamlet populated by a Celtic tribe called Insubres nestled on a rise between the rivers Olona and Nirone, tributaries in the system of waterways flowing from the Alps down to the great river Po. The hamlet, postulated to have been contained in the small square between the modern opera house and city hall, quickly earned the name “Mediolanum,” probably derived from the Latin expression “Medio Planum” meaning “Middle of the Plain.” The Romans set up a colony a half-mile away from the Insubres across the river Nirone; today marked by the somewhat underwhelming San Sepolcro Square behind the Ambrosian Library. You can see what that might have looked like here. As the Roman Republic gave way to the Roman Empire, Mediolanum consecrated itself as important depot from which Rome’s military supply lines to Gaul and Germania originated, and the city grew rapidly: the two communities quickly merged, so the river Nirone was diverted away from the city center such that it now hugged the western half of the city’s new walls before merging with the Olona. The growing city's new eastern limit was delineated by the next river over, called the Seveso. Like the Nirone, the Seveso was also diverted into the Olona, forming a wide pool south of the city which would become one of northern Italy’s busiest inland ports. You can get an idea of what the city might have looked like here.

The end of the Roman Empire is a difficult and contentious topic. Certainly, the old gibbonian narrative of a catastrophic fall has been discredited in modern historiography; recent histories prefer to examine how the empire’s borders ossified, with legions along the frontier increasingly reliant on local recruitment chipping away central authority. The end of Rome’s Empire certainly rendered Southern Italy’s cities unsustainable, dependent as they were upon pan-mediterranean grain trade. Italy’s center of population moved northwards to the broad plain of the River Po, where the fertile hinterland could more easily support urban populations.

Skipping over several centuries, by the time the German Empire experienced its eleventh-century apex under the Ottonian dynasty and could attempt to reaffirm the ancient political union of the Italian and German crowns, Milan was the most prominent city in Italy and an economic powerhouse more than capable of affirming its independence against encroachment by the Empire. Milan commanded an integrated hinterland of close to 100,000 inhabitants, and while not surpassing Rome in religious or symbolic importance, certainly eclipsed the old capital in economic terms. Milan’s hinterland was characterized by regular and intense transit of people and goods up and down the Olona from the Po into the city; while Milan’s aristocrats pushed for an aggressive policy to impose the city’s authority over its smaller neighbors.

The authorities in the growing medieval metropolis constructed a second ring of larger defensive walls encasing the old roman city limits; this growth meant that the waterways which had once circumnavigated the city now passed through it. You can get an idea of what the city might have looked like here. The river Olona quickly became unsuitable for the quantity of river traffic to and from the river Po, so by the thirteenth century it was flanked by an artificial canal called the “Naviglio Grande;” one of the largest public works undertaken in Medieval Europe. Two centuries later, a second artificial “Naviglio” canal connecting Milan to the river Ticino in Pavia was also constructed, while the city’s internal waterways were redeveloped under the oversight of Leonardo Da Vinci. Mirroring these developments was the ongoing construction and redirection of canals and waterways all over Lombardy. You can get an idea of Milan's suburban hydrography from this map; which you'll note also includes the date of individual canal's completion (the city's modern street grid is in yellow).

These canals would continue to be important routes for people and goods until the unification of Italy and the introduction of steam power. In the fascist ventennium specific policies were put in place to favor more modern forms of transportation; save for the port facilities in the city's southwestern quadrant, Milan's canals were diverted underground to make room for a modern ring road and broad avenues bisecting the city. You can see the underground path of the city's waterways here, although many of them, especially those in dead center of the city (Corso Vittorio Emanuele, Piazza Duomo, and Via Torino) are redirections into the city's sewage system.

Today, Milan and Lombardy has a contentious relationship with its canals and waterways. While many picturesque canals still cross the countryside as in the map linked above, the presence of railroads and highways has rendered them largely useless. However, in the last thirty years empty warehouses and manufactories along the “Navigli” canals in Milan have been in converted into nightlife venues and loft apartments, while the city's old inland port has been turned into a walkable promenade; interest in these vestiges of pre-industrial travel is again growing. The character and uniqueness of the canals has led to a contentious proposal to uncover some of the city's old waterways in an effort to reclaim some of the city's history.

If you'd like to browse some more images see if you can recover any of the following documents (they might be available online):

Facchinetti, Grazia, and Cristina Miedico. Proceedings tied to Expo Milano 2015: Di Città in Città: Insediamenti, Strade, e Vie D'Acqua Da Milano Alla Svizzera (“From City to City: Settlements, Roads, and Waterways between Milan and Switzerland”) Lombardy Archeological Authority, Angera (VA) 2014.

Bellosta, Roberto. “La Vita Economica a Milano e in Lombardia Nei Secoli XI-XV” (“Economic Life in Milan and Lombardy between the XI and XV Centuries”) Volume Celebrativo Dell’80° Anniversario Del Rotary Club Di Milano", a Cura Di G. Rumi, G. Sena Chiesa, G. Soldi Rondinini, L. Antonielli, Editrice Abitare Segesta (Milano) 2003.