Idrijca

The Idrijca is a river in western Slovenia that flows through the Idrija Hills and Cerkno Hills. It is a tributary of the Soča river.
The area of the upper Idrijca, from its source to the town of Idrijca (a distance of about 30 km), is part of the "Krajinski Park Zgornja Idrijca" ("Upper Idrijca Natural Park"). Here there are many karst features and an important diversity of plant species.
Geography.
The Idrijca river has a length of and a drainage basin with an area of .
This river is one of the few places where the Marble trout ("Salmo marmoratus") is found.
Course.
The source of the Idrijca is in "Mrzla Rupa", part of the small town of Vojsko in the municipality of Idrija, western Slovenia, at an altitude of .
From its source, the Idrijca flows to the southeast and then, after its confluence with the Beca river, turns to the northeast. Then, after passing through the town of Idrija, the river turns to the northwest and joins the Soča in Most na Soči, to the south of Tolmin.
The Idrijca passes through the municipalities of Idrija, Cerkno and Tolmin.
Main tributaries.
Most of the tributaries of the Idrijca river are small stream. The most important is the Bača with a length of ; it joins the Idrijca in the village of Bača pri Modreju, in the municipality of Tolmin.
One of the tributaries is the "Jezernica" river, that is only long and which originates from the Wild Lake ().