Dolines and Pools
The origin of the dolines, the characteristic depressions in the ground named from the Slovenian word “dol” (down deep), has always been a matter of dispute. They do not all have a regular, circular or conical shape, vary in size from a few metres to hundreds of metres in diameter, and may possess a deep central sink hole intersecting large and inclined rock strata.
Their characteristics are complex and variable as they are for caves.
The Karstic phenomenon resembles an instantaneous snapshot of multiple locations, or perhaps a single frame of a video taken over a geological timescales. Whereas most dolines develop from sinkholes,hardly ever visible, and take on an inverted-funnel shape, other large examples are the result of collapses of ancient cavity systems into deep abysses.
Many of the dolines, chasms and abysses that exist today have a sinkhole at the deepest part where surface water disappears underground. The bottoms of the depressions are filled with red earth that accumulated in past eras as a result of limestone denudation. This indicates that the fill materials are slowly but inexorably descending into the depths below.
Going down towards the bottom of these dolines, the temperature decreases by 1 degree every 10 metres. One example of this phenomenon that can be easily reached is the Doline of the Percedol Pool.
The Karstic environment does not exhibit much flowing surface water. The inhabitants, who herded sheep and goats, needed to collect water.
Consequently they extracted clay from the caves to line the natural depressions of the dolines, as a first step in the collection of rain water.
In this way they created new environments where amphibians such as toads and frogs could breed and fresh water plants could take root. The pools need to be periodically cleared of plant growth in order to avoid being overgrown.
Since the construction of aqueducts these basins have been progressively abandoned and will disappear, along with the plant and animal life they support, if not maintained.
A complex of pools and ice-deposits exists below the village of Draga Sant’Elia, although in a rather neglected condition. Not far away, just beyond the former Pese boundary, there is a path to the village of Nazirje – Nazirec, where more pools can be found, as well as what was the last ice-deposit that retained its own roof.