Po Valley

Source: Wikipedia, the free encyclopedia.
Not to be confused with Valle Po.
The Padan Plain in Northern Italy (green) and the Po river basin in the Plain (red circle)
Map showing the river Po and tributaries in the Padan Plain. Note the numerous Italian Lakes on the margin of the Alps.
Trentino-Alto Adige, and 8) Friuli-Venezia Giulia

The Po Valley, Po Plain, Plain of the Po, or Padan Plain (Italian: Pianura Padana [pjaˈnuːra paˈdaːna], or Val Padana) is a major geographical feature of Northern Italy. It extends approximately 650 km (400 mi) in an east-west direction, with an area of 46,000 km2 (18,000 square miles) including its Venetic extension not actually related to the Po river basin; it runs from the Western Alps to the Adriatic Sea. The flatlands of Veneto and Friuli are often considered apart since they do not drain into the Po, but they effectively combine into an unbroken plain, making it the largest in Southern Europe. It has a population of 17 million, or a third of Italy's total population.[1]

The plain is the surface of an in-filled system of ancient canyons (the "Apennine Foredeep") extending from the Apennines in the south to the Alps in the north, including the northern Adriatic. In addition to the Po and its affluents, the contemporary surface may be considered to include the Savio, Lamone and Reno to the south, and the Adige, Brenta, Piave and Tagliamento of the Venetian Plain to the north, among the many streams that empty into the north Adriatic from the west and north.

Geo-political definitions of the valley depend on the defining authority. The Po Basin Water Board (Italian: Autorità di bacino del fiume Po), authorized in 1989 by Law no. 183/89 to oversee "protection of lands, water rehabilitation, the use and management of hydro resources for the national economic and social development, and protection of related environment" within the Po basin, has authority in several administrative regions of north Italy, including the plain north of the Adriatic and the territory south of the lower Po, as shown in the regional depiction included with this article. The law defines the Po basin as "the territory from which rainwater or snow and glacier melt flows on the surface, gathers in streams of water either directly or via tributaries...".[2] The United Nations Environment Program includes the Alps and Apennines as far as the sources of the tributaries of the Po but excludes Veneto and that portion of Emilia-Romagna south of the lower Po; that is, it includes the region drained by the Po but only the Po and its tributaries.[3]

The altitude of the valley through which the Po flows, exclusive of its tributaries, varies from approximately 4 m (15 feet) below sea level in the Polesine subregion (the delta around Ferrara)[4] to about 2,100 m (6,900 feet) at the river's origin in the southern Piedmontese province of Cuneo, also known as the Provincia granda. The valley is crossed by a number of affluents running down from the Alps in the north and from the Apennines in the south. The Po's major affluents include the Tanaro, Scrivia, Trebbia, Panaro and Secchia in the south, Dora Riparia, Dora Baltea, Sesia, Ticino (draining Lake Maggiore), Lambro, Adda (draining Lake Como), Oglio (draining Lake Iseo) and Mincio (draining Lake Garda and called Sarca in its upper reaches) in the north.

Geology

Main article: The river Po
Po near source in the western Alps

The Po Valley and the Adriatic overlay a

Apennines but also from the Alps. The shoreline of the Adriatic depends on a balance between the sedimentation rate and isostatic factors. Until about 1950, the Po delta was prograding into the Adriatic. After that time due to human alteration of geologic factors, such as the sedimentation rate, the delta has been degrading and the coastline subsiding, resulting in ongoing contemporaneous crises in the city of Venice
, where much irreplaceable art and architecture is likely to be lost due to soaring sea level in the next centuries. Where the land surface now dips below sea level the river must run at a relative elevation between dikes.

The Malossa

gas condensate field was discovered in 1973 and produces at depths of 6 km (4 miles) from the Upper Triassic Dolomia Principale dolomite and the Lower Jurassic Zandobbio dolomite, capped by the Lower Cretaceous Marne di Bruntino marl.[5]

Geography

Carmagnola, countryside near the river Po
Rice fields in the province of Vercelli, eastern Piedmont.
Landscape of the Bassa: a farm in the province of Cremona, southern Lombardy.

The Po Valley is often regarded as a syncline, or dip in the crust due to compression at the edges. Regardless of whether this concept accurately describes its geology, the valley is manifestly a sediment-filled trough, or virtual syncline, continuous with the deeps of the Adriatic Sea. The surface terrain is therefore divided into two overall types of landform: the plain, or flat surface of the fill, and the anticline at the edges, taking the form of hilly country in which the outcrops of the original rock are visible along with alluvial fans formed from the outwash of the more severe anticlinal terrain; that is, the Apennines and the Alps.[6]

The valley is broadly divided into an upper, drier part, often not particularly suited for agriculture, and a lower, very fertile, and well-irrigated section, known in

Emilia as la Bassa, "the low (plain)". The upper areas of the Po valley take local names which reflect in their meanings their being modestly suited for farming. So we have the Piedmontese vaude and baragge, the Lombard brughiere and Groane, or, exiting from the Po valley proper, the Friulian
magredi, areas remote from easily reachable water tables and covered with dense woods or dry soils.

This specific meaning for "lower plain" derive from a geologic feature called the fontanili ("spring") line or zone, a band of springs around the Val Po, heaviest on the north, on the lowermost slopes of the anticline. It varies from a few kilometres to as much as 50 km (30 miles) wide. The fontanili line is the outcrop, or intersection, of the anticline's

intermittent streams of the mountains tends to disappear below ground only to spring out again in the spring zone.[7]
The spring zone is often called "the middle valley."

megalopolis stretching from Turin to Trieste.[8]

The bassa Padana was settled and farmed earliest, in Etruscan and Roman times. After the collapse of the Roman Empire (5th century AD), lack of maintenance of the irrigation systems[9] associated with a cooling climate phase (i.e. the so-called Migration Period or The Dark Age Cold Period[10][11]) led to the progressive waterlogging of the Po Valley and the natural depressions on the right side of the Po River turned in vast swamp basins.[12] The waterlogging process of the area continued until the 10th century influencing the human sustenance and settling practices. According to historical-archaeological data, indeed, the wetlands were exploited for fishing as well as for transport by boat while the early medieval sites settled on the fluvial ridges, in topographically higher and strategic position[13] in the surrounding swampy meadows.

The Po Valley has been completely turned to agriculture since the Middle Ages, when efforts from monastic orders, feudal lords and free communes converged. The older and smaller cities deriving from ancient times are still located there.

According to historical maps and documents the land reclamation of the Po Valley reached its peak during the

Modern Age
(17th–18th centuries), with the last marsh areas only being reclaimed in the 20th century: channels and drainage system are still active and allow the Po Valley to be drained and be cultivatable.

Climate and vegetation

Natural vegetation (central-European broadleaved trees) of the Padan Plain

The Po Valley has a generally

relative humidity
throughout the year. The climate of the Po Valley becomes increasingly warmer and more humid farther south and east.

Winters are cool and damp, with January mean temperatures ranging between 0 and 5 °C (32 and 41 °F).

thunderstorms and sudden hailstorms have the potential to produce large hail, dump large quantities of rain, and be highly destructive to crops. The largest hail is produced by intense supercell thunderstorms, with significant agricultural costs.[14] Tornadoes are also not uncommon in the plains of the valley. For these climatological considerations the Friuli-Venezia Giulia is an important extension beyond the Po River plain itself, as these are situated downwind of the mountains and upwind of moisture sources from nearby seas. Spring and autumn are well-marked and pleasant. Both winter and summer are less mild in the lower parts along the Po, while the Adriatic Sea
and the great lakes moderate the local climate in their proximity.

maples, ash, and other central-European trees. The largest remaining fragments of forest are located around the Ticino River and are protected by a Biosphere Reserve.[15]

The Po Valley as seen by the ESA's Sentinel-2.

History

Prehistory and antiquity

The Po Valley has had traces of inhabitation since at least 780,000 years ago, when the first big glaciation of pleistocene took place. Sites like Monte Poggiolo may have served as refuges of human populations fleeing the terribly cold conditions of northern Europe during the subsequent glaciations along pleistocene.[16] The valley was covered by sea level in warm times, but glaciations could cause a lower sea level that allowed big mammals and humans to migrate from Africa and the Middle East to central and western Europe through an empty and open Po valley, avoiding the barrier of the Alps, reaching the Loire Valley, and Iberian Peninsula, and then, when glaciation retreated, the rest of continental Europe.

Urban development began in the Po Valley much later than in southern Italy or Greece. The first known ancient inhabitants of the thick forests and swamps were the

Etruscans, who left names such as Parma, Ravenna and Felsina, the ancient name of Bologna. The Etruscan domination left significant marks and introduced urban civilisation, but was short-lived. [citation needed
] Its inhabitants, the
Etruscans and Greeks
.

Diachronic distribution of Celtic peoples:
  core Hallstatt territory, by the 6th century BCE
  maximal Celtic expansion, by 275 BCE
  Lusitanian area of Iberia where Celtic presence is uncertain
  the "six Celtic nations" which retained significant numbers of Celtic speakers into the Early Modern period
  areas where Celtic languages remain widely spoken today

By 196 BC, Rome was master of the woody plains and soon displaced the Etruscans, dotting the region with bustling colonies, clearing the land, fighting the last rebel tribes and gradually imposing its own civilisation. [citation needed]

Middle Ages

The defence of the Carroccio during the battle of Legnano (1176) by Amos Cassioli (1832–1891)

The

Catholicism
.

The

Papal benediction that defeated emperor Frederick Barbarossa at the Battle of Legnano
in 1176.

Between the 10th and 13th centuries, concurrent with the Medieval Warm Period climate phase, the European population grew substantially, almost tripling (in Northern and Central Italy, the urban population doubled), and increasing the demand for cultivated lands. Cereals became a more significant constituent in the average diet and in the agrarian regime compared to the centuries before, leading populations to reconfigure the medieval natural landscape for agricultural purposes. In creating new land for cultivation and settlement, the European communities triggered a massive landscape transformation through woodland clearance, arable intensification, the development of irrigation systems and the drainage of wetlands. Land reclamations works profoundly modified many European regions. In Central Po Plain the earliest evidence of attempts to clear the forests and drain the wetlands is mentioned in historical documents from the late 8th century, but only from the 10th to 13th centuries were land and water management activities actually carried out widely.[19][20][21]

Further civil wars escalated in the Guelph-Ghibelline reciprocate bloodbath of the 13th and 14th centuries. The Signorie came from spent out Communal institutions. With Venice's expansion on the eastern mainland in the first half of the 15th century and Milan's supremacy in the center and west the region (not significantly diminished by the Black Death of 1348) reached unprecedented peaks of prosperity. Vast areas were irrigated and cultivated with the most modern techniques available. The population averaged some 50 people per square kilometer, a very high standard for those times.

Early modern

1585 map depicting the eastern Po Valley and river delta, Vatican Museums.

In 1494, the ruinous

Canton Ticino, not technically a part of the Padan region), and the Venetian domain was invaded, forcing Venice into neutrality as an independent power. In the end, Spain prevailed with Charles V's victory over Francis I of France at the Battle of Pavia
in 1525.

The

industry recovered, especially the textile
branch, its pillar. When the
War of Spanish Succession traded Milan to Austria
, government and administration improved significantly. Though the peasantry began a century-long plunge into misery, cities prospered and grew.

When

Savoy dynasty
would emerge to serve as a springboard for Italian unification.

Late modern and contemporary

The

Risorgimento, after an unsuccessful start in 1848 and 1849, triumphed ten years later in Lombardy, which was conquered by a Franco-Piedmontese army. In 1866 Veneto joined young Italy, thanks to Prussia's defeat of Austria. Poverty in the countryside increased emigration to the Americas, a phenomenon which subsided in the central region towards the end of the 19th century, but persisted in Veneto
well into the 20th century. Industry grew rapidly, thanks to an abundance of water and literate manpower.

The

Third Reich
was using for war production, preventing their destruction: on 25 April 1945 a general insurrection in the wake of the German defeat was a huge success. Most cities and towns, notably Milan and Turin, were freed by the partisans days before the Allies arrived.

After the war, the Padan area took the lead in the

autonomy for the Padan area which they call Padania
.

Economy

The Po Valley is one of the most important industrial and agricultural areas in Europe. Hydroelectricity is produced by the flow of the Po. The river is extensively used for irrigation for the region's agriculture.[22]

Pollution

Po valley is considered the worst area in Europe for air quality.

nitrogen oxides, which are mainly produced by cars' diesel and petrol engines. To shed light on the danger for humans living polluted environments, Chicago Energy Policy Institute[25] has developed the Air Quality Life Index (AQLI), a system capable of analyzing air pollution worldwide. According to AQLI findings, Po valley air pollution affects inhabitants so hard that it cuts off about half a year of their life expectancy. The main reasons for the high amount of air pollution over the Po valley are strictly connected to livestock and factories. The so-called "NPK fertilizers", made of nitrogen, phosphorus and potassium, along with manure emissions from intensive breeding and high levels of nitrogen dioxide released by diesel and petrol engines are all accountable for this disastrous air condition in Northern Italy. The region of Lombardy produces also vast amounts of animal waste, a big contributor to pollution. It delivers more than 40 percent of Italy's milk production, for example, while over half of the Italian pig production is located in the Po Valley.[26]

According to research published in

Padova, Como and Venice
rank eleventh, fourteenth, fifteenth, seventeenth and twenty-third respectively.

The data show that many cities in the Po Valley suffer the most serious impact at European level due to poor air quality, first of all the metropolitan area of Milan, thirteenth in the ranking in terms of fine particulate impact, where any year 3967 premature deaths occur – approximately 9% of the total.

References

  1. ^ "FACT SHEET: Po River Basin" (PDF).
  2. ^ "The Po Basin Water Board, Italy". CABRI-Volga. Retrieved 4 June 2009.
  3. ^ "Po". United Nations Environment Programme, Division of Early Warning and Assessment (DEWA), Global Resource Information Database (GRID) - Europe. Archived from the original on 1 August 2009. Retrieved 4 June 2009.
  4. ^ "the Water Board". Consorzio di Bonifica II Circondario - Polesine di San Giorgio. Retrieved 6 June 2009.[permanent dead link]
  5. ISBN 0891813063
    , pp. 525-538
  6. ISBN 978-0-521-28965-8
    .
  7. ISBN 978-88-88192-04-8. Archived from the original
    (PDF) on 15 December 2019. Retrieved 6 June 2009.
  8. ISBN 978-0-7425-1628-1
    .
  9. OCLC 49550805
    .
  10. S2CID 27661057
    .
  11. ISSN 1814-9332
    .
  12. ISSN 0169-555X
    .
  13. ISSN 2352-409X
    .
  14. doi:10.1175/1520-0450(1973)012<0338:AGDOTH>2.0.CO;2
    .
  15. ^ "Valle del Ticino | United Nations Educational, Scientific and Cultural Organization".
  16. ^ Human migration into Europe during the late Early Pleistocene climate transition Article in Palaeogeography, Palaeoclimatology, Palaeoecology · October 2010
  17. ^ "Ethnic identity and government". britannica.com. Encyclopædia Britannica. Retrieved 2 October 2022.
  18. ISBN 978-2-503-54058-0
    .
  19. hdl:2434/598152
    .
  20. ISBN 978-1-4073-5855-0
    .
  21. ISSN 1461-4103
    .
  22. ^ "Po". Infoplease. Sandbox Networks, Inc., publishing as Infoplease. Retrieved 3 December 2015.
  23. ^ "Nitrogen dioxide and fine particles are threatening Po valley air quality". Retrieved 27 January 2021.
  24. ^ "Nitrogen dioxide over northern Italy". Retrieved 28 January 2021.
  25. ^ "Air pollution hotspots in Europe". Retrieved 29 January 2021.
  26. ^ "Italy's polluted Po Valley gasps for fresh air". 28 February 2019. Retrieved 27 January 2021.
  27. S2CID 231687871
    .

External links

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