The Eau Rouge is a small, 15 km long stream

Stream

A stream is a body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, "crick", gill , kill, lick, rill, river, syke, bayou, rivulet, streamage, wash, run or...

 in the Belgian

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 province

Province

A province is a territorial unit, almost always an administrative division, within a country or state.-Etymology:The English word "province" is attested since about 1330 and derives from the 13th-century Old French "province," which itself comes from the Latin word "provincia," which referred to...

 of Liège

Liège (province)

Liège is the easternmost province of Belgium and belongs to the Walloon Region. It is an area of French and German ethnicity. It borders on the Netherlands, Germany, Luxembourg, and in Belgium the provinces of Luxembourg, Namur, Walloon Brabant , and those of Flemish Brabant and Limburg . Its...

, right tributary of the Amblève

Amblève (river)

The Amblève or Amel is a 93 km long river in eastern Belgium in the province of Liège. It is a right tributary of the river Ourthe. It rises near Büllingen in the High Fens , close to the border with Germany.Tributaries of the Amblève are the rivers Warche, Eau Rouge, Salm and Lienne...

. It starts in the Hautes Fagnes and ends in Challes, near Stavelot

Stavelot

Stavelot is a Walloon municipality located in the Belgian province of Liège. On January 1, 2006, Stavelot had a total population of 6,671. The total area is 85.07 km² which gives a population density of 78 inhabitants per km².-History:...

 in the river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 Amblève.

The river gets it's name from the colloration of the stones and river bed which are rich in iron oxide which are red in color.

The river has lent its name to the Eau Rouge corner, one of the best-known corners in Formula One

Formula One

Formula One, also known as Formula 1 or F1 and referred to officially as the FIA Formula One World Championship, is the highest class of single seater auto racing sanctioned by the Fédération Internationale de l'Automobile . The "formula" designation in the name refers to a set of rules with which...

 racing circuits in the Circuit de Spa-Francorchamps

Circuit de Spa-Francorchamps

The Circuit de Spa-Francorchamps is the venue of the Formula One Belgian Grand Prix and the Spa 24 Hours endurance race. It is also home to the all Volkswagen club event, 25 Hours of Spa, run by the Uniroyal Fun Cup. It is one of the most challenging race tracks in the world, mainly due to its...

 at the point where the track crosses it for the first time.

The river has particularly geomorphological

Geomorphology

Geomorphology is the scientific study of landforms and the processes that shape them...

 interest, as it appears to be the old position of the Warche

Warche

The Warche is a river in eastern Belgium .From its source at Losheimergraben on the Belgian-German border, it flows roughly west about 50 km, across the south of the Hautes Fagnes region....

 river. The river used to be a frontier several times, including an administrative limit under the Roman Empire

Roman Empire

The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

 between Köln

KOLN

KOLN, digital channel 10, is the CBS affiliate in Lincoln, Nebraska. It operates a satellite station, KGIN, on digital channel 11 in Grand Island. KGIN repeats all KOLN programming, but airs separate commercials...

 and Tongeren, and between Belgium

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 and Prussia

Prussia

Prussia was a German kingdom and historic state originating out of the Duchy of Prussia and the Margraviate of Brandenburg. For centuries, the House of Hohenzollern ruled Prussia, successfully expanding its size by way of an unusually well-organized and effective army. Prussia shaped the history...

 from 1830 to 1919.