POPOVO POLJE

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7.1.  GENERAL INTRODUCTION :
Popovo Polje contains the remnants or ruins of a great many ponor mills. This Section of the Popovo Polje Webpages deals with this interesting aspect of karst water utilization and karst hydro-engineering. It should be noted that the Dobromani Ponor Mills and those at Pridvorci are dealt with in greater pictorial detail in their own Sections located elsewhere on this Website.

Many of the karst ponor-mills along the Trebišnjica River in Popovo Polje were constructed prior to the period of the Austro-Hungarian Administration. Mikuleć & Trumić (1976) seem to indicate that they have survived from the earlier period of Turkish Rule. In a personal communication, Milanović seems to agree with this. According to Petrović & Kovacina (1984), their personal investigations, which have included the detailed interrogation of owners of some ponor-mills, have indicated that some mills were purchased directly from Turkish Noblemen, who sold them for gold. The then owner of the Dučića Ponor-mill near the village of Lug said that his ponor-mill was the oldest and had been purchased for gold from Turkish Noblemen by his Slavic family ancestors in the year 1819.
It is well documented that during their occupation of Bosnia and Hercegovina, the Austro-Hungarian Monarchy employed the services of several karst engineers to devise and implement hydromelioration projects on the karst. Although much of this work had military overtones, it should be remembered that much was also achieved to ease the extreme karst-environmental conditions that prevailed upon the indigenous population. Due to their effirsts, agricultural activities in particular became more sustainable. 
However, in respect of similar activities during Turkish Rule, we currently have nothing other than scant information.
Karst Ponor-mills were also built in Livanjsko Polje and in Lipovo Polje in Lica.

From a purely speleological viewpoint, the very presence of a ponor mill indicates not only the self-evident presence of a ponor (or sometimes an estavelle) but also the possibility that the ponor may offer a point of physical access to a ponor cave. This is not always the case. For example, a whole series of ponor mills may have been constructed by various villages along the Trebišnjica River in a ponor zone, where some of the ponors in their natural condition may only ever have been inaccessible fissures feeding water into parts of the same karst conduit which does contain accessible input channels elsewhere within the ponor zone. However, for the efficient performance of the ponor mill, there obviously has to be a minimum water-absorption capacity.
The ponor mills of Popovo Polje are usually located near or adjacent to the principal waterway of the Trebišnjica Karst River, formerly in its natural condition, the largest disappearing karst river (locally = ponornica) in Europe. Bearing in mind that the permanent course of this river in the dry summer months stopped at Dražin Do, most of the Ponor Mills further downstream could only have been utilized for the production of flour during the wet Winter or Spring months.
More than 20 ponor-mills were still operational after World War 2. but their demise has been due to both the construction of modern bulk-processing flour mills but even more so to the total destruction of the whole way of historical life in Popovo Polje, caused by the development of the region-wide project "Hidroelektrane na Trebišnjici" since the mid 1960's.

The Society is now better able to locate the locations of ponor mills due to our acquisition of 1 : 25 000 Scale and 1 : 2 500 Scale Topographic Maps and an increasing coverage of the area with high-resolution Aerial Photogrammetry images.
The 1 : 2 500 Scale Maps may be regarded as historical documents, insofar as they were published in the 1950's during the period of F.S.R. Jugoslavija, (N.R. / S.R. Bosna i Hercegovina), using data from the original Austro-Hungarian Maps.

Theoretically, there are supposed to be more than 50 ponor mills in Popovo Polje...Milanović,.in a personal communication,
states that along Popovo Polje, more than 20 ponor-mills were operational after World War 2.  Petrović.& Kovačina have
counted at least 50. We have so far accounted for 50 mills. 
The demise of the mills was due to the construction of modern bulk-processing flour mills.

Statistics.:...Currently entered in this on-line register are :-
1....Number of ponor mills accounted for herein  = 50.
....(of which 31 have known names and 19 have no known names.)
...... and of which .....
2a. Number of ponor mills identified as being situated on the left bank of the Trebišnjica River = 27.
2b. Number of ponor mills identified as being situated on the right bank of the Trebišnjica River = 11.
2c. Number of ponor mills whose exact location is presently unknown = 12.
3....Number of ponor mills about which we have no specific Data = 10.
4a. Number of ponor mills known to have been designed with 1 x Turbine / Millstone set = 11.
4b. Number of ponor mills known to have been designed with 2 x Turbine / Millstone sets = 2
5....Number of ponor mills with known accessible caves or shafts = 6.
6....Number which are reversible-flow dual-use Estavelle Mills = 2+. 

It should be noted that reversible-flow Estavelle Mills had dual functionality. These units when in a "ponor" mode were used as
flour mills. However, when in their "vrelo" or "spring" mode, they were utilized as sources of fish - for the gaovica salmonoid
fish. It seems that there were many more of these units than have been commonly reported on. Further details will be posted
here in due course.

1. Generalni../.General, (locational / descriptive).
.
DESNA OBALA = Right riverbank;
DOBRO OČUVAN = Well preserved;
LIJEVA OBALA = Left riverbank;
OBIM = Extent; Circumference; Size;
OŠTEĆEN = Damaged;
SAČUVAN = Preserved;
SEOSKI MLIN = Village Mill;
STANJE = Condition;
U LOŠEM STANJU = In Bad Condition;
UNIŠTEN = Ruined;
ZAPUŠTEN = Neglected.

Note :
Where descriptions about the condition of the structure have been taken from other texts and has not been verified as being the present condition, an asterisk * will suffix the adjective.

2. Tehnički../.Technical.
.
BENT; BENAT ili BEDEM  = Cofferdam;
Usually constructed to be waterproof to protect the mill from being flooded by the nearby river.
DONjI MLIN = Lower Mill;
FOŠTANAC =
GORNjI MLIN = Upper Mill;
KOBILA = Base Anchor Frame (=Keel);
KOLO = Turbine Wheel;
LOPATICA = Scoop;
MLAZNICA = Spout of Water-input Channel;
MLIN; MLINICA  = Mill (singular).
MLINOVI; MLINICE  = Mills (plural);
MLINSKI KAMEN = Mill-stone
MLINSKO KOLO = Mill-wheel
MLINSKI NASIP = Mill Dam;
OSIGURAVAJUĆI OBRUČI = Securing Hoop;
PAPRICA =
PERAJE (LOPATICE) = Blade (Scoop);
PLOČA = Disc / Plate;
POSTAVAK = Bearing;
PREĆNIKA =..Ø..= Diameter;
RASKLAD =
RGA =
SENJ = Drive-Spindle / Drive Shaft;
TULAC = Cylinder;
TRUPINA = Hull;
TURBINA =  Turbine;
VRATILO = Drive-Beam;

The construction of ponor-mills in the entrance channels of ponors was certainly an innovative use of the potential energy arising from water naturally discharging into the endokarst. This ingenious use of hydro-energy was employed to drive the flour mills which processed the grain cultivated in Popovo Polje. In the case of Popovo Polje, the harvest would have been mainly of the special "100-day" crop which, as its name suggests, would have been planted, grown and harvested with the 100-day cultivation period in the central and lower parts of the polje. For the remaining period of the year, the polje-floor was inundated.
Many ponor-mills were constructed with associated infrastructure such as river dams and ancilliary out-buildings.
Below is an illustration of the three principal dispositions of ponor mouths in respect of their adjacency to the riverbed and riverbank of the Trebišnjica River in Popovo Polje.

The water discharging into the base of the mill structure would drive a turbine, originally of wooden construction but latterly of metal, and this in turn would be directly connected via a drive-shaft to a set of mill-stones on a higher level above. The quantity of flow being delivered to the wooden turbine was regulated by the opening or closing of a sluice-gate or "water gate" on the outside of the cylindrical outer wall. The control for this gate was situated at the top of the cylindrical outer wall directly above the gate. This water-control device is known as a penstock.
The cylindrical or neo-cylindrical outer stone wall is of waterproof construction, enveloping the mill infrastructure. When the mill is in operation, this wall may be partly submerged, acting as a coffer-dam.

Further below is an illustration indicating how a ponor mill was positioned into the ponor-mouth.

.
.
Slika PPPM3..Elementi glavnog objekta mlinice :-
1...Bedem građevina;
2...Zahvatna građevina;
3...Najniža etaža sa obrtnim kolom;
4...Gornja etaža sa mlinskim kamenovima;
5...Pristupno stepenište;
6...Krov mlinske etaže.

Illustration PPPM3..Main Elements of the Mill Building :-
1...Cofferdam structure.
2...Input-water structure.
3...Lowest level with Turbine wheel;
4...Upper level with Mill-stones;
5...Entrance steps.
6...Roof level of mill. 
.
.
.
The construction drawing below indicates the specific geometric relationship between the input-water channel and the Turbine Wheel, in order to maximize the power-potential of the incoming water. The Turbine Wheels were originally mostly constructed of wood, with the scoop-shaped Turbine Blades actually having been carved out of solid wood.
The Illustration gives geometric details from both the Plan View aspect (a.) and the Vertical Cross-sectional aspect (b.).

It was the usual tradition to give each water-wheel (Turbine) in each mill its own name.

Illustration PPPM6...Plan-view of the Construction Details of the Turbine Wheel Components

Photo PPPM7.. Illustrating some of the components shown in the above illustrations
as seen in the Sedlarska mlinica - lower level Double Turbine Chamber. 

The Bračkovića mlinica, at Pridvorci continues to adopt the traditional system of allowing villagers to have their grain milled in return for a payment "in kind" of 10% by weight of the flour produced.
The image below indicates the flour issuing from the millstones into an adjacent flour-pit.

Of the two millstones above the Turbine Chamber, it is only the top one which is connected to the drive shaft rising up from the Turbine. We have not completed our survey to determine the dimensions of millstones.
The millstone is usually metal-strapped around the whole of the outside-edge circumference, to prevent it from breaking apart and destroying the whole mechanism if it should break during use.
 
 

Additional simple but separate mechanisms permit a manually operated brake to be applied by the miller, whilst another permits the fine adjustment of the space between the millstones to be undertaken at will. In the latter case, this permits the production of different grades of fineness of the flour being produced, a practical choice which may be necessary to reflect the end-use of the flour.

[Text and Images to follow]

-.Perišića mlinica, (type-3 water input)
Lokacija / Location :  GPS Co-ordinates :..42º 47' 29" N. : 018º 09' 08" E. @ 257m.asl. /..desna obala R. Trebišnjica;
Situated only 33.5m. from the nearby Trebinje-Ljubinje Road. Exactly 36.5m. upstream (eastwards) from the Ponor-mill is a road junction where a small bridge takes a minor cross-polje road across the Trebišnjica River and the polje floor to Jasenica Lug.
Vlasništvo / Ownership :..Formerly in the ownership of the late Mr Luka Perišić and now his sister Mila Bilbija in Sarajevo and his son.
Date of Construction :..[not yet known].
Opis / Description :..1 x Cofferdam; 1 x Turbine; 0 x Millstone set; associated separate buildings, now being re-used as private houses.
Stanje / Condition :..zapušten / neglected; this mill is in excellent structural condition and could be made to work again. It is very overgrown with thick vegetation.

-.Drapića mlinica, (type-3 water input)
Lokacija / Location :  GPS Co-ordinates :..42º 47' 31" N. : 018º 08' 53" E. @ 262m.asl. /..lijeva obala R. Trebišnjica;
383m. downstream (westward) from the small bridge that takes a minor cross-polje road across the Trebišnjica River and the polje floor to Jasenica Lug.
Vlasništvo / Ownership :..Mr Đoko Drapić [bh], whose family still lives in Gornje Dobromani, although Đoko Drapić now resides in Makarska, Croatia.
Date of Construction :..1902.
Opis / Description :..1 x Bedem (excellent structural condition); 1 x Turbine; 0 x Millstone set; internal Mill-House roof is totally ruined but restorable; 2 x associated external ancilliary buildings, one of which provided living and sleeping quarters. The Mill Dam across the Trebišnjica was destroyed by the HET Co. when the riverbed was shotcreted.
Stanje / Condition :..zapušten / neglected; this mill is in good structural condition and could be made to work again.

Please follow this Link to the sub-Project webpages about the Dobromani Ponor Mills.

-.Gomiljani mlin, (type-3 water input)
Lokacija / Location :  GPS Co-ordinates :..[not yet known] - lijeva obala R. Trebišnjica;
Vlasništvo / Ownership :..
Opis / Description :..1 x bedem in good condition; 
Stanje / Condition :..uništen; Ponor remains active.
Date of Construction :..[not yet known].

-.Gornji mlin,
Lokacija / Location :  GPS Co-ordinates :..[not yet known]  - lijeva obala R. Trebišnjica;
Vlasništvo / Ownership :.
Opis / Description :..
Stanje / Condition :...
Date of Construction :..[not yet known].

-.Kusalovića mlinica,
Lokacija / Location :  GPS Co-ordinates :..[not yet known]  - lijeva obala R. Trebišnjica;
Vlasništvo / Ownership :.
Opis / Description :..Originally with a downstream river dam; 1 x Cofferdam; 1 x Turbine Wheel.
Stanje / Condition :..zapušten;
Date of Construction :..[not yet known].

-.Ljepavni mlinovi, ("mlinovi" implies the presence of at least 2 mills),
Lokacija / Location :  GPS Co-ordinates :..[not yet known]  - lijeva obala R. Trebišnjica;
Vlasništvo / Ownership :.
Opis / Description :..
Stanje / Condition :...
Date of Construction :..[not yet known].

 -.Praskan mlinica,
Lokacija / Location :  GPS Co-ordinates :..[not yet known]  - lijeva obala R. Trebišnjica;
Vlasništvo / Ownership :.
Opis / Description :
Stanje / Condition :..
Date of Construction :..[not yet known].

-.Slućemnik mlinica,
Lokacija / Location :  GPS Co-ordinates :..[not yet known]  - lijeva obala R. Trebišnjica;
Vlasništvo / Ownership :.
Opis / Description :
Stanje / Condition :..
Date of Construction :..[not yet known].

 -.Srednja mlinica (lokalni = "Bunar mlinica"),
Lokacija / Location :  GPS Co-ordinates :..[not yet known]  - lijeva obala R. Trebišnjica;
Vlasništvo / Ownership :.
Opis / Description :
Stanje / Condition :..
Date of Construction :..[not yet known].

-.Vrbanj mlinica,
Lokacija / Location :  GPS Co-ordinates :..[not yet known]  - lijeva obala R. Trebišnjica;
Vlasništvo / Ownership :.
Opis / Description :
Stanje / Condition :..
Date of Construction :..[not yet known].

[awaiting further images]

Please follow this Link to the webpages about the Pridvorci Ponor Mills.

-.Sedlarska mlinica (zapad),
Lokacija / Location :  GPS Co-ordinates :..42º 41' 49" N. : 018º 19' 58" E. @ 263m.asl. - lijeva obala R. Trebišnjica, 40.6m. downstream of the bridge.
Vlasništvo / Ownership :..[not yet known]
Opis / Description :..1 x Cofferdam in bad condition;
Stanje / Condition :..zapušten;
Date of Construction :..[not yet known].

[awaiting further images]