Vodenica doline ranks among the sinkholes. The sinkholes are the surface indicators of a strong and aggressive sub-terrestrial stream that dissolves and repels a larger rock material deeper into the underground. There’s a permanent water source at their bottom, a sign of subterrestrial streaming.
Vodenica doline is the largest and deepest doline on the Karst Educational Trail from Lebice cave to the Krupa river. It lies in the middle of the forest at Brstovec village. It is 46m deep. A small walled spring is at its bottom that people once used to drink and water livestock. Vodenica doline is watery during droughts, too. In 2011, the Municipality of Semič restored the Vodenica spring.
According to oral sources, there used to be many dormice on the slope of the Vodenica doline, which had shelters in old oak, hornbeam and beech trunks. The locals here hunted them regularly for food and the fur.