The Devon Karst Research Society.
Part 5.3.  Eastern Herzegovina.
Gacko Polje, BiH-RS Trebinje Region - Gacko Municipality.

Updated 20 May 2007.

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Gatačko (Malo) Polje -  Гатачко (Мало) Поље
Section 6.0.1.    PONORS  -  ПОНОРИ  -  PONORI
kod selo Srđevići  -  код село Срђевићи :


Image G(V-M)P1-SrđPM.
The course of the Rijeka Mušnica
and the upstream entrance to Gatačko (Malo) Polje near Srđevići.
Map extract taken from the restricted-access Yugoslav 1 : 25 000 Series,
Sheet 575-4-2. Nevesinje (Nadinići), 1974.
[showing 1km. grid squares]
[Image file size = 610 x 900 pixels / 921 kB.]

The observable Ponor located in the vicinity of selo Srđevići is :-

Ponor "Srđevići", (alternative name = Ponor "Jama"),
..........(status = intermittent, only inactive at absolute minimum river flow);

Specific details about this ponor and its associated Ponor Mill are given below.
This ponor is in the Catchment of the Rijeka Trebišnjica.

This interesting ponor area is now mostly abandoned and growing wild.
There are no operating ponor mills in or near selo Srđevići.

A return visit is planned to record further underground details.

Gatačko Polje -  Гатачко Поље

GPS Co-ordinates :..43° 10' 02"N. : 018° 28' 24"E. [5 Sats].
This is situated at an elevation of 924.92m. asl. and is located in the Malo Polje on the right bank of the Rijeka Mušnica, several hundred metres downstream of the village of Srđevići. The position of the ponor is at the north-eastern foot of Osoje and is clearly indicated on the Map above.
At medium to high water levels, this is the first of a whole string of ponors draining the Gatačko (Malo) Polje. At absolute low water level, it is left high and dry. Reputedly, it can absorb water approximately at the rate of 65m3 sec-1., although we have our doubts about this.

The main accessible entrance area of this ponor cave contains the remnants of water-control features associated with a ponor mill actually located well inside at the rear of the entrance chamber. We have no name for this ponor mill.

Photo (above-left)..General view of the main accessible entrance to Ponor "Jama" (Srđevići).
(Photo :  B. Lewarne, 02 September, 2006.)
Photo (above-right)..The view inside the entrance chamber, looking out.
To the left of the feet of the standing figure is the inner end of a water channel directing the incoming water towards the ponor mill turbines behind the photographer.
(Photo :  B. Lewarne, 23 August, 2006.)

Photo (above-right)..A view of the ponor mill at the rear of the entrance chamber.
(Photo :  B. Lewarne, 19 August, 2006.)
Photo (above-right)..A closer view of the ponor mill at the rear of the entrance chamber.
(Photo :  B. Lewarne, 23 September, 2006.)

Beyond the entrance chamber behind the ponor mill, the inside of the ponor cave is quite constricted. We were still looking for reason why one of the alternative names for this ponor was "Jama". So far, it was mostly horizontal. After crawling through the rock-floored first constriction (see Photo below), the passage opened out very slightly and various vertical phreatic tube passages were observed leading off to somewhere below. The first one on the left was steeply inclined and was soon followed by another two in the floor of the passage straight ahead. Here were no cave sediments, just bedrock limestone. 


Photo (above-left)..General view of the small passage leading off above and behind the ponor mill structure at the back of the entrance chamber.
(Photo :  Igor Trklja, 23 August, 2006.)
Photo (above-right)..A view of the termination of the short horizontal passage located at the back of and above the terminal shaft.
(Photo :  B. Lewarne, 02 September, 2006.)

Photo (left)..A view of the terminal shaft.
(Photo :  B. Lewarne, 02 September, 2006.)

Beyond the third (terminal) shaft in the floor, the short horizontal section ended abruptly, (see Photo above).
The final shaft in the floor was oval shaped, vertical for its first 4 metres and orientated along the same fracture as the whole of the short length of horizontal passage. (see Photo on the left).
Two metres down from the top of this shaft and below a phreatic "eye hole" in the shaft wall on the left side, was a metal bar, purposely placed in position, perhaps as a belay point.

Clearly, there were no other visitors in this ponor, so a few rocks were thrown down into each of these vertical shafts with the result that we could not hear anything having reached the bottom of any of them.

Photo (above-left)..A view of a small subsidiary ponor at river level, just below and a few metres north of the main ponor cave entrance.
This suddenly became active on 02 September, 2006., after the river level rose slightly.
Photo (above-right)..A closer view of the subsidiary ponor which is absorbing Mušnica River water,
highly contaminated with waste mineral content originating upstream in the mining pit in Gatačko (Veliki) Polje and from mineral-processing plants.
(Photos above :  B. Lewarne, 02 September, 2006.)

The subsidiary ponor, pictured in the two images above, was unapproachable due to the slippery white sediment slime and sludge in and around the small depression. Indeed, the River Mušnica at this point had broken through the thick, deep sediment-sludge banks and was pouring this filth directly into the underground. Note the sediment staining on the plant growth around the depression.

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