The Vydra river is the headstream of the Otava river. The wild mountain river with a stony bed runs through a nice valley, which is protected in the reserve called Povydri (Vydra valley).
The river begins at the confluence of the Modravsky Potok (Modrava Stream), Roklansky Potok (Roklan Stream), and Filipohutsky Potok (Filipova Hut Stream) near the village of Modrava. The headstream of the Vydra river is the Modravsky Potok stream, which springs on the north-western hillside of Luzny mountain (Lusen – 1,373m) at an altitude of 1,210m above sea level.
Vydra joins the Kremelna river near the small village of Cenkova Pila. This is the beginning of the Otava river.
The Vydra is 23 km long (from the spring of the Modravsky Potok stream to the confluence with the Kremelna river), and it takes its water from an area of 147 square km.
The red marked path leads along the river between Modrava and Cenkova Pila. The section between the settlements of Antygl and Cenkova Pila is known as the Povydri information path (Vydra valley), and it leads through the Povydri reserve (Vydra valley).