An interesting hydrological element of natural heritage is the spring Zaganjalka under the Cerkno hill, in the gully Volkova grapa near the Zakrog homestead. Zaganjalka is reached by descent from the chapel at Lajse.
It represents an interesting Karst phenomenon, characterised by the changing water flow. At normal flow, it takes seven minutes for the spring to almost dry up and the water to come gushing again from the depths.
Zaganjalka has become a Slovene technical term for all springs of this type, named after Zaganjalka in the Cerkno region.