Waterfall Veliki Kozjak, Kobarid, Slovenia Waterfall Veliki Kozjak near the city of Kobarid. The stream Kozjak forms 6 waterfalls before it joins river Soča. The largest and most visited is Veliki Kozjak, which is 15m high. Here the river cut an underground hall in the stones and you can feel almost like being in the cave. The waterfall falls into a "bowl" of emerald-color water.