Canyon Unca

The Rijeka Unac rises as a mill stream, under the Šator mountain at 876 m above sea level, flowing through the Pojila clisure, four basins and three further clisures. It flows through the Una National Park to Martin Brod, through the southernmost clisures, and up to 350 metres. The total flow is about 66 kilometres, and has an altitude difference of about 450 metres.

The River Unac is the first large tributary of the River Una, which with its exceptional cleanliness and coldness enhances the River Una, but it is also and additionally rashlađuje. The Unac is fed by water from dozens of different tributaries and springs. The river can become too dry in one part, due to the reduced flow of water from the surrounding Sumerian streams, leaving small lakes overflowing with fish. Taj dio puta Unac teče kao ponornica, springing last from the Crnog vrela, oko 3 kilometra prije ušća u Unu (Izvor: National Park Una - http://nationalpark-una.ba/bs/kategorija.php?id=6).

Quaternary sediments cover the lowest relief positions in the canyons of the rivers Una and Unca, and their wider valleys. Prema svim abježjima vrlo su divers diversni. The most widespread are alluvial and colluvial deposits, and marshy sediments and till deposits.

The ecosystems in the canyon of the River Una and its tributaries of the River Unca have a less-more-refugial-relict character, and the largest number of palaeoendemic and tertiary relics is represented by the ecosystems of the carbonate pucotina of the upper part of the River Una and its right tributaries of the River Unca.

In the context of the management of the Šumava and Šumava land, it is necessary to ensure the protection of the delicate soil exposed to erosion, especially the steep drops in the canyon dijelovima of the watercourses of the Una, Unca and Krka rivers, on which the Šumava cultures are situated and which are exposed to a high risk of fire.

The Unca Canyon, from Crnog Vrelo to Berek, represents an exceptional diversity, due to its geomorphological, hydrogeological, hydrological and biodiversity features. Due to the poor monitoring in this area, there are currently no long-term, detailed monitoring plans on how to register, valorise and protect all the features in an appropriate way. Ovo podrazumjeva i neustále praćenie svih proces. The organisation of a single centre (campus) with a teaching, educational and visual function at all levels of education (Rastoke sub-district) would be very useful in this regard.

The Unca Canyon from Martin Brod to Crnog Vrela (which is a natural monument) is not protected as a special nature reserve.

Ovo područje također omogućava čitav niz turističkih i sportsko-rekreativnih djelatnosti od ecoturizma (područje Luka i Rastoke), obilazaka u rekreativne i obrazovne svrr (izvori, vrela, drage, morfološke znamenitosti i sl.(Source: Spatial plan of the sub-region of special abundance of character for the Federation of BiH ''Sliv rijeke Une'' 2007-2027, Federal Ministry of Spatial Planning).