Odra (Kupa)

Odra () is a river in central Croatia. It is long and its basin covers an area of . Its source is in the Žumberak mountain, southwest of Zagreb. It flows eastwards, passes south of Velika Gorica, then turns south-east, more or less parallel to the river Sava. It flows into the river Kupa near Odra Sisačka, just northeast of Sisak, also just before the Kupa joins the river Sava.
The upper flow of Odra has been significantly altered by humans, by the digging of the long canal Sava-Odra(-Sava) south of Zagreb, as a measure against flooding (first put to use in 1979).
There are several etymologies suggested for the name "Odra". One is that it comes from the Croatian word "oderati" (to cut through). The other is that it comes from the Indo-European root *wodr (water).