The Volarnk Brook, a left tributary of the Soča River, springs below The Krn Mt. in gullies almost 2 000 m above sea level. The gullies are dry most of the year, they merge into three spring branches.
    Each of them is special in itself, but the common feature is a large number of waterfalls in brookbeds and korita with constant water. Its quantity increases by flow, as it is fed by many small springs in brookbeds and along them.
    Brook basin is built by various rocks. The oldest are the layered Dachstein limestone with layers and inlays of dolomite and the plate-like, massive and layered Bača dolomite with chert. They are between 200 and 215 million years old.
    A small patch is formed by Jurassic or Liassic micrite and calcarenite limestone with chert poles and subordinate clayey marl, aged from 175 to 199 million years.
    The bulk of the rocks are represented by various Cretaceous limestones. They are between 70 and 100 million years old.
    The youngest ones are Ice Age moraine and screes. They are still forming.
    The surface is very rugged, steep and somewhere precipitous. There are also small planes. On them the villages of Krn, Vrsno, Selce and Selišče were built, the last one a little above the outlet.
    The Volarnk flows into the Soča only 173 m above sea level.

Let's take a look at each of the spring branches:
    Mrzlca is the left one,
    Branch of the Simon Gregorčič waterfall is the middle one and
    Branch of the waterfall in Brinta is the right one.

Explanation of the names.