Nadiža has a powerful karst spring on the slopes of Ponce, located to the northwest above the mountain hut in Tamar. After emerging from a fault line, the water cascades over a dolomite ledge, forming a small waterfall. It continues its path in a series of cascades down to the valley floor, where it disappears into the underground through gravel. This is also the first source of the Sava Dolinka, which resurfaces the second time in Zelenci.