Una is a 212 kilometers long river with the source in Croatia near Srb, close to the boarder with Bosnia and Herzegovina, at the altitude of 448 meters above sea level. It ends near Jasenovac, also in Croatia, where it meets bigger river Sava. Most of the Una river flows through Bosnia and Herzegovina and people in Bosanska Krajina are very proud of Una river. Spring of Una river is located in karst area that is famous for it's strong springs where a lot of water comes through the ground on the surface.
Maximum depth of the spring 205 meters
First organized exploration of the spring occurred in 1999 by the French expedition. French explorers dived to the depth of 51 meters and could not continue further. Croatian explorers continue the exploration in 2007 with much more luck and details. They say that the spring walls goes to the depth of 30 meters almost vertically and after that it become more narrow forming a crack 10 meters wide that goes to the northwest. It becomes deeper and narrower until it reaches depth of 83 meters and become wide just 5 meters.
Then the crack suddenly turns to the south and goes to the depth of 123 meters. After that it goes to the northwest again with the crack that is in some places only 2-3 meters wide. Maximum depth that is reached by Croatian divers was 205 meters.
Water temperature on the spring is 7-8 degrees Celsius. The place itself is very beautiful so we recommend everybody to visit it and enjoy the nature that surrounds the spring.
We thank Mrs. Tihana Goričnik that allow us the use of her pictures in this article.