Bača springs under Slatnik and Lajnar carving a deep valley Baška grapa (lit. Baća ravine). During the whole length of 21,4 km of pools and runs it's guarded by trees and followed by a road and a railway. It flows into Idrijca at Bača pri Modreju. The first 3 km are a fish reserve for marble trout the rest is all fishing water divided into two parts by a dam in Klavže. Throuhout both parts live grayling and trout with the exception of rainbow trout which is not present in the upper part.