Olona
Encyclopedia
The Olona is a 71 km long Italian
river, which runs through the provinces of Varese
and Milan
.
The Olona has more than one source; in fact it has six main springs. Three springs are located in the Rasa Valley, just above Varese
, whereas other three springs pour water down from the southern side of pleasant Valganna
- since 1877 these still clean and fresh mountain waters were historically used, and still are, to make beer
in a renowned local brewery
, Poretti, now run by Carlsberg.
The Olona river passes through the deep Olona Valley, cut in the poruous soils of the upper Po Valley
, eventually flowing in the plain after Legnano
. It is in the Olona valley part that the river gets much of the industrial pollution which has made it a byname for venomous waters for decades. Only in recent years attempts to restore the river's ecology have proven at least partially successful. After Legnano, the Olona river flows in the plain until Milan
, usually contained in narrow artificial banks. New expansion basins are being constructed to prevent floodings, which are rare but can be devastating under conditions of sudden intense rain in the upper river flow.
In ancient times, the 131 km long Olona continued its course south of Milan, through the Province of Pavia
, eventually joining the Po
. Due to massive hydraulic works, that started in the Roman Age and were continued until the 20th century, just before Milan the river leaves its natural bed and begins to flow under the street level, like a sewer, feeding and becoming part of the complex groundwater system of the city.
Immediately after passing through a tunnel under the Naviglio Grande
, the Olona flows into the Lambro Meridionale, that carries its waters in the Lambro
. Until the late 1980s, a branch of the Olona fed the Darsena of Porta Ticinese
(the inner harbour of Milan). The water flow in this branch was first reduced, and finally completely cleared, when city authorities realized that the river's pollution began to threaten the Darsena and the Naviglio Pavese, which originates from it.
The Olona river counts 39 tributaries. The principal tributaries are the torrents Vellone, Bevera
Varesino, Lanza (or Gaggiolo), Bozzente, Lura, Merlata and Mussa.
This river originates from the join of many secondary watercourses in the country south of Milan, and receives also a notable amount of water from several natural springs ("fontanili"). Near San Zenone
it flows into the Po.
Altough it is usually indicated simply as Olona on topographic and road maps, it may be called either Olona inferiore (Lower Olona) or Olona meridionale (Southern Olona) for better distinction with the northern Olona.
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
river, which runs through the provinces of Varese
Province of Varese
The Province of Varese is a province in the Lombardy region of Italy. Its capital is the city of Varese but its largest city is Busto Arsizio....
and Milan
Province of Milan
The Province of Milan : /) is a province in the Lombardy region of Italy. Its capital is the city of Milan. The provincial territory is highly urbanized, resulting in the third highest population density among the Italian provinces with more than 2,000 inhabitants/km2, just behind the provinces of...
.
The Olona has more than one source; in fact it has six main springs. Three springs are located in the Rasa Valley, just above Varese
Varese
Varese is a town and comune in north-western Lombardy, northern Italy, 55 km north of Milan.It is the capital of the Province of Varese. The hinterland or urban part of the city is called Varesotto.- Geography :...
, whereas other three springs pour water down from the southern side of pleasant Valganna
Valganna
Valganna is a comune in the Province of Varese in the Italian region Lombardy, located about 60 km northwest of Milan and about 13 km north of Varese. As of 31 December 2004, it had a population of 1,506 and an area of 12.5 km²...
- since 1877 these still clean and fresh mountain waters were historically used, and still are, to make beer
Beer
Beer is the world's most widely consumed andprobably oldest alcoholic beverage; it is the third most popular drink overall, after water and tea. It is produced by the brewing and fermentation of sugars, mainly derived from malted cereal grains, most commonly malted barley and malted wheat...
in a renowned local brewery
Brewery
A brewery is a dedicated building for the making of beer, though beer can be made at home, and has been for much of beer's history. A company which makes beer is called either a brewery or a brewing company....
, Poretti, now run by Carlsberg.
The Olona river passes through the deep Olona Valley, cut in the poruous soils of the upper Po Valley
Po Valley
The Po Valley, Po Plain, Plain of the Po, or Padan Plain is a major geographical feature of Italy. It extends approximately in an east-west direction, with an area of 46,000 km² including its Venetic extension not actually related to the Po River basin; it runs from the Western Alps to the...
, eventually flowing in the plain after Legnano
Legnano
Legnano is an Italian town and comune with 59.147 inhabitants in the province of Milan, about from Milan.It's crossed by the river Olona, and it's the 13th town for inhabitants in Lombardy....
. It is in the Olona valley part that the river gets much of the industrial pollution which has made it a byname for venomous waters for decades. Only in recent years attempts to restore the river's ecology have proven at least partially successful. After Legnano, the Olona river flows in the plain until Milan
Milan
Milan is the second-largest city in Italy and the capital city of the region of Lombardy and of the province of Milan. The city proper has a population of about 1.3 million, while its urban area, roughly coinciding with its administrative province and the bordering Province of Monza and Brianza ,...
, usually contained in narrow artificial banks. New expansion basins are being constructed to prevent floodings, which are rare but can be devastating under conditions of sudden intense rain in the upper river flow.
In ancient times, the 131 km long Olona continued its course south of Milan, through the Province of Pavia
Province of Pavia
The Province of Pavia is a province in the region of Lombardy in northern Italy. Pavia is the capital.It has an area of 2,965 km², and a total population of 493,753...
, eventually joining the Po
Po River
The Po |Ligurian]]: Bodincus or Bodencus) is a river that flows either or – considering the length of the Maira, a right bank tributary – eastward across northern Italy, from a spring seeping from a stony hillside at Pian del Re, a flat place at the head of the Val Po under the northwest face...
. Due to massive hydraulic works, that started in the Roman Age and were continued until the 20th century, just before Milan the river leaves its natural bed and begins to flow under the street level, like a sewer, feeding and becoming part of the complex groundwater system of the city.
Immediately after passing through a tunnel under the Naviglio Grande
Naviglio Grande
The Naviglio Grande is a canal in Lombardy, northern Italy, joining the Ticino river near Tornavento to the Porta Ticinese dock, also known as the Darsena, in Milan. It drops 34 m over 49.9 km. It varies in width from 22 m to 50 m from Tornavento to Abbiategrasso, dropping to 15 m between there...
, the Olona flows into the Lambro Meridionale, that carries its waters in the Lambro
Lambro
For the river in Cilento, see Lambro . For the genus, see Lambro .The Lambro is a river of Lombardy, northern Italy, a left tributary of the Po....
. Until the late 1980s, a branch of the Olona fed the Darsena of Porta Ticinese
Porta Ticinese
Porta Ticinese is a former city gate of Milan, Italy. The gate, facing south-west, was first created with the Spanish walls of the city, in the 16th century, but the original structure was later demolished and replaced in the early 19th century...
(the inner harbour of Milan). The water flow in this branch was first reduced, and finally completely cleared, when city authorities realized that the river's pollution began to threaten the Darsena and the Naviglio Pavese, which originates from it.
The Olona river counts 39 tributaries. The principal tributaries are the torrents Vellone, Bevera
Bévéra
The Bévéra or Bevera is a river of southeastern France and northwestern Italy. Its source is in the Maritime Alps, near Moulinet in the French Alpes-Maritimes department. It flows generally southeast, through Sospel, crosses the Italian border and discharges into the river Roya, near Ventimiglia...
Varesino, Lanza (or Gaggiolo), Bozzente, Lura, Merlata and Mussa.
"Southern" or "Lower" Olona
Also a 41 km long water stream that entirely flows in the province of Pavia is called "Olona". Some historical researches, supported by geographic and geological data, suggest that the bed of this river is nothing but the southernmost part of the ancient Olona, that the Romans diverted to Milan. This fact easily explains why the two rivers carry the same name.This river originates from the join of many secondary watercourses in the country south of Milan, and receives also a notable amount of water from several natural springs ("fontanili"). Near San Zenone
San Zenone al Po
San Zenone al Po is a comune in the province of Pavia, Lombardy, Italy....
it flows into the Po.
Altough it is usually indicated simply as Olona on topographic and road maps, it may be called either Olona inferiore (Lower Olona) or Olona meridionale (Southern Olona) for better distinction with the northern Olona.