Karst of the Dinaridian chain is one of the most striking karst complexes in the world. In comparison with other karst regions, Herak (1977) states that this is a "karst prototype where all its phenomena are withheld, from geomorphological to hydrogeological".
Through millions of years, chemical and mechanical powers of water formed one of the most impressible karst relieves. 
Melting of the carbonate rocks caused by water enrichened with carbon dioxide formed karst in a long karst-forming process.
Due to the geological structure, before all carbonate rocks which are sometimes several thousand meters thick, as well as their tectonic disturbancy, the karst-forming process was very intensive in the past, thus developing all the terrestrial and underground karst forms.
On the rocks' surfaces various karst forms like carrens, sinkholes, fields, valleys etc. were developed, while in the underground there are pits, caverns and caves.
Rock melting is greatly helped by the atmospheric carbon dioxide contained in downfalls. By filtration through various soil layers, water enrichness with the carbon dioxide produced as a result of plants' roots activities, bacteria and many other organisms who inhabit the soil, thus becomes quite corrosive and melts carbon rocks excessively.
Inside some underground hollows water melts even their ceilings which collapse and form sinkholes. 
After passing through many carbon rocks, water becomes saturated with calcium carbonate. After reaching an underground cave filled with air, it filtrates through its ceiling. When this water enters the underground, lesser amount of carbon dioxide is released into the cave's atmosphere. In this very moment, a small amount of calcium carbonate also falls from the ceiling. Its amount grows in time with every drop of water that filtrates through the ceiling, thus forming a stalactite. The remaininig part of the water drop falls to the ground and releases what's remained of the carbon dioxide, while calcium carbonate falls on the bottom of the cave, under the stalactite. That excess of calcium carbonate accumulates through thousands of years and forms another speleological ornament - a stalagmite. 
When stalactite and stalagmite join together, a pillar is formed.
From ancient times, underground waters drew people's attention. Men often descended into the underground to fill the supplies of water which were always scarce. The uneven distribution of downfalls and variable permeability of the karst underground caused the battle of evermore between men and water - people fought either for water, either against it.
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Due to the complex geological structure and high precipitation (2600 mm), the Štirovača valley has all the specific hydrogeological karst phenomena.
The intensive tectonics of this area brought into collision rocks of different hydrogeological features.
The valley's flanks were built out of badly permeable dolomite rocks and their impermeable clastic sediments. On the joints of these two types of rocks numerous springs emanate.
At the time of intensive rainfalls or snow melting, the springs swell intensively. Huge water masses flow downstream, forming deep ditches in impermeable soil layers. When they come into the central part of the valley, which is built out of well-permeable carbon karst rocks, water sinks into the underground and feeds waters that flow deep below.
Underground water courses are ususally very complex and not yet entirely explained in details, predefined with tectonic disturbance and the structure of the terrain, mutual layout and relation of permeable, badly permeable and impermeable sections and barriers. Due to this situation, shifts between locally connected underground waters and completely isolated and privileged underground courses are to be expected.
When waters of Gacka river were painted (1974) and tracked, their unquestionable connection with springs under the sea's surface and underground courses which end in the Adriatic sea was stated.
In the zone of karst, there is almost no part which would not be exposed to pollution without it being spotted downstream. Adding the fact that underground waters, due to their relatively short residing in the secondary porosive karst underground (cracks and hollows formed by tectonic activity and the chemical influence of water) will not autopurify like in other areas, we come to the conclusion that only those springs which are not fed with underground waters are free from pollution. 
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