Vipava (river)

The Vipava (in Slovene), Vipacco (in Italian) or Vipau (in Friulian) is a river that flows through western Slovenia and northeastern Italy.
The Battle of the Frigidus was fought in 394 near the river, which was named "Frigidus" ('cold') by the Romans.
Geography.
The Vipava river has a length of , in Slovenia and in Italy. Its drainage basin has an area of about ( in Slovenia).
The river flows through the southern part of the Vipava valley; this valley goes from the village of Podnamos, Slovenia, to Savogna d'Isonzo, in Italy.
Course.
The source of the Vipava is close to the city of Vipava, in the municipality of Vipava, western Slovenia, at an altitude of .
From its source, the Vipava flows to the northwest and follows this direction through the Vipava valley. It passes through the Slovenian municipalities of Vipava, Ajdovščina, Nova Gorica, Renče–Vogrsko and Miren–Kostanjevica. Then, at an altitude of , the river crosses the border and gets into the Italian "comune" of Savogna d'Isonzo (Friuli-Venezia Giulia region) and finally joins the Soča river.
There are not important tributaries, only very small streams.