PRESIHAJOCA JEZERA NA PIVSKEM 8 – MALO DRSKOVSKO JEZERO
INTERMITTENT LAKES IN THE PIVKA BASIN 8 – MALO DRSKOVSKO JEZERO
V pivski kotlini se nahaja 18 obicajno pojavljajocih se jezer. Proti severozahodu si sledijo Sembijsko jezero, Kalsko jezero, Laneno jezero, Backo jezero, Kljunov ribnik, Veliki dol (za Kalcem), Veliko in Malo Zagorsko jezero, Veliko in Malo Drskovsko jezero, Parsko jezero, Radohovsko jezero, Klenski dol, Palsko jezero, Petelinjsko jezero, Krajnikov dol in Jeredovce.
There are as many as 18 regular lakes in the Pivka basin. Towards the northwest the following lakes occur: Sembijsko jezero, Kalsko jezero, Laneno jezero, Backo jezero, Kljunov ribnik, Veliki dol (za Kalcem), Malo Zagorsko jezero, Veliko Zagorsko jezero, Veliko Drskovsko jezero, Malo Drskovsko jezero, Parsko jezero, Radohovsko jezero, Klenski dol, Palsko jezero, Petelinjsko jezero, Krajnikov dol and Jeredovce.
Malo Drskovsko jezero je srednje od treh jezer, ki so med seboj najverjetneje povezana s podzemnim vodnim tokom (Habic 1975). Iz Velikega Drskovskega jezera voda podzemno ne odteka v strugo Pivke, temvec proti Malemu Drskovskemu jezeru. Ojezerjeni kotanji med seboj locuje 150 m širok in 20 m visok hrbet. Kotanja Malega Drskovskega jezera je nenavadna, saj zelo spominja na manjse izvirno-ponorno krasko polje. Okrogla globel jezera se namrec proti jugovzhodu potegne v ozko zatrepno dolino, ki se zakljucuje z visoko prepadno steno. Pod njo je nekaj metrov globoka vodoravna jama, ki jo domacini imenujejo Podmou (spodmol). To je izvirna jama Malega Drskovskega jezera. Takrat voda izvira iz vec manjsih jamskih rovov ter grusca, ki se nahaja v podnozju zatrepne stene. Voda odteka po krajsi strugi do ovalne globeli, kjer se razlije v jezero. Ko kolicina iztekajoce vode upade, voda ne doseze vec sirokega dela globeli, temvec ponika skozi poziralnike v spodnjem delu struge, priblizno 200 m pred ponorom. Vecji del Malega Drskovskega jezera se prazni skozi razpoke v dnu, ob visjih vodostajih pa zlasti skozi ponorno jamo na severnem robu globeli. Domacini tudi to jamo poimenujejo Podmou. Medtem ko je izvirna jama zasuta predvsem s kamenjem, je ponorni Podmou dodobra napolnjen z drobnozrnatimi sedimenti, stene v njem pa so tudi deloma zasigane. Tako kot v Velikem Drskovskem jezeru je tudi v Malem novembra 2000 maksimalni vodostaj za stiri metre presegel srednje vrednosti, pri tem pa se je povrsina jezera podvojila.
Malo Drskovsko jezero is the second in the line of three lakes, which are most probably interconnected by an underground flow (Habic 1975). The sinking water of Veliko Drskovsko jezero does not flow towards the Pivka riverbed, but reappears in Malo Drskovsko jezero. The depressions of the two lakes are separated by a 150 m wide and 20 high ridge. The shape of the karst depression of Malo Drskovsko jezero is unusual and is very reminiscent of a classical overflow karst polje. This roundshaped depression narrows into a small pocket valley with a high precipitous rock wall on its southeastern side. At the bottom of the wall is a several metre long horizontal cave called Podmou, which is the spring cave of Malo Drskovsko jezero. During high waters, water comes out of several small holes and rubble which is accumulated at the bottom of the wall. The water outflows through a short channel to an oval-shaped depression where the lake occurs. When the discharge of the spring reduces, the water does not reach the abovementioned depression, but sinks into ponors located in the lower part of the channel, about 200 m before the main ponor. The major part of Malo Drskovsko jezero empties into fissures in the bottom and, at higher water levels, mainly into a ponor cave on the northern side of the depression. This cave is also called Podmou. In contrast with the spring cave, which is covered mainly with rubble, the ponor cave is to a great extent filled with fine-grained sediments and its walls are partly sintered. In November 2000, the mean water level of Malo Drskovsko jezero was exceeded by 4 m (as was also the case with Veliko Drskovsko jezero) and its surface area doubled.
Vir / source: Gregor Kovacic & Spela Habic, Kraska presihajoca jezera Pivke (JZ Slovenija) ob visokih vodah novembra 2000 Intermittent karst lakes of Pivka basin (SW Slovenia) during high waters in november 2000, Acta carsologica, 34/3, 5, 619-649, Ljubljana, 2005