NATuRE TRAIL

Občina Bovec

the secret trails of the Kanin karst waters www.bovec.si

Virje waterfall at different water levels dificulty 1 VIRJE WATERFALL THE TRAIL >1h 1km AnD The spring of Glijun The »Glijun and Virje – the secret trails of the Kanin karst LEGEND VIRJE WATERFALL waters« thematic nature trail enables visitors a chance to info AnD The spring of Glijun a l o n g the emerald trail discover the complex and mysterious karst dephts world of Kačje brdo i info point T1 thematic point the Kanin Mountain Range. In it, big quantities of water the secret trails flow from waterfall to waterfall, from crack to crack and P parking lot hiking trail from stone to stone. Most of the water sources spring out on relatively few spots at the southern foot of the Kanin R viewpoint road of the Kanin Mountain Range. In the cases of the Boka Waterfall and stream, the spring of Glijun or Nemčlja in the Možnica Kanin karst waters valley, the water sees the light of day in the form of a big Srednje čelo waterfall or almost a river. Apart from that, also smaller i springs or streams can be found in the area. kova jama I č BOVEC Ma Alpe Adria Trail THE PATHS OF WATER DROPS Pl. na Pečeh Č Krničar Heavy rainfall, water-rich rivers and snowy mountains KLUŽE With an average yearly rainfall of 3500mm, the Kanin PREDEL PLUŽNA Mountain Range is considered to be one of the richest Kladenki i P VIRJE i BOVEC in in terms of water. Sometimes, the amount of 450 mKoritnica yearly rainfall even exceeds 4000mm. This is reflected in Spring of Glijun i Virje PLUŽNAWaterfall VRŠIČ P E 430 m BOKA the high water levels of the rivers and Kanin karst springs. info Boka GlijunT1 Soča The waters are the highest in spring and autumn, which all T2 fans of river sports are well aware of. Due to snow melting ČEZSOČA Glijun in the mountains, the high waters and good navigability ŽAGA KAL- are usually retained until mid-summer. Snow is the main GOLF T3 Plužna reason for high water levels in the spring and summer. The ETNOlake BOVEC LETALIŠČE winter snow cover on the Kanin Karst Plateau is usually more than five meters deep, in karst depressions it can reach Srnica a depth of more than ten meters. High water level in the autumn is usually associated with abundant autumn rains. 0 m 100 m 200 m Alpe Adria Trail Cave Srnica The mysterious paths of water drops ŽAGA,BOKA

What happens to a drop of water when it falls on the bare KLUŽE karst surface of the Kanin Mountain Range? It first flows Lead partner and editor: En Hec d.o.o. Pravljica v Bovcu concept, project and manager: PREDEL on a karst rinennkaren and slowly deepens it in doing so. Metka Belingar. Author of trail content and Slovene texts: dr. Jurij Kunaver. Expert BOVEC revision: dr. Blaž Komac. Translations: Evridika Cuder. Photography: Metka Belingar, i Sometimes it starts to make its way further into the moun- VIRJE Koritnica LEGENDA T1 Jurij Kunaver, Dejan Ristić, Matjaž Vidmar. Graphic design and illustrations: Metka PLUŽNA i - informativna točka - učne točke tain by percolating through the limestone gravel. It can also Belingar. Prepress and printing: Copigraf. Quantity: 2500 copies. Bovec, 2014. KAL-KORITNICA / LEGEND info pints tematic points - parkirni prostor - pohodniška pot This document has been produced within the project Pravljica» v Bovcu« with the BOKA P parking place fall on a snow cone and remain preserved in the karst depres- TRENTA walking trail financial assistance of the European Agricultural Fund for Rural Development. The Glijun LETALIŠČE Soča Bovec Boka VRŠIČ R - razgledna točka - cesta sions or kotliches until the snow starts to melt in the summer. Managing Authority Rural Development Programme for the period 2007-2013, the view point road 0 m Ministry100 m of Agriculture200 m and 300the Environment. m 400 Responsiblem 500 for m the content: EN HEC d.o.o. Or it immediately slides to great depths on a karren. The ČEZSOČA

ways in which it can reach the source are numerous! ŽAGA PO MOČ ROŽ Plužna The pools below the waterfall carved in the rock have a depth of KOBARID The water in the karst underground PANORAMA approximately 3.5m. The average water temperature is 8 °C. ETNO BOVEC In the karst underground water gradually forms larger water- courses. Its paths run much like tree branches. Only cavers other thematic nature trails around Bovec can discover them, but even for them this undertaking is usually hard, since running water in the form of subterra- TIC Bovec Tel: +386 (0)5 384 19 19 nean lakes and siphons often blocks their way. Water conta- Trg golobarskih žrtev 8 Gsm: +386 (0)31 388 700 ining free CO2 has the capacity to dissolve limestone. A liter 5230 Bovec, Slovenia E-mail: [email protected] of water of the nearby spring of Glijun contains 95mg of CaCO3. Rain- and meltwater also contain dissolved carbon dioxide. Vast quantities of water have so far dissolved so much rock on their way from the surface to the spring that project by: En hec d.o.o. the surface has lowered by several ten meters every billion Evropski kmetijski sklad za razvoj years. This has caused the creation of large karst caves and podeželja: Evropa investira v podeželje. Projekt sofinancira EU. www.bovec.si typical eroded surfaces, or karst. Glijun at different THE SPRING OF GLIJUN water levels The Plužna altitude: 430m Below: the Plužna dam accumulation lake lowest discharge: 0,1 – 0,15m3/s average discharge: 0,25 – 0,5m3/s average water temperature: 6°C water hardness - total: ~5°GH

THE KARST SPRING OF GLIJUN EXPLOITATION OF GLIJUN WATER The source of the stream of Glijun arises at an altitude of FOR THE HEPP PLUŽNA approximately 430m in a small valley head at the foot of HEPP Plužna was built between 1927 and 1931 during the walls of Peči. The spring is filled up with glacial mate- the Italian state administration of the Upper Soča Valley, rial and slope gravel, so the water must find its way out to when additional electricty was needed for the planned the surface among many stones. Bedrock basis is not far construction of a railway between the towns of Most below the surface, as it can be seen in the side stream bed na Soči and Tarvisio. Since the construction never took of the occasional stream of Srnica, where the water has place, the HEPP Plužna later served the electrifica- carved out a narrow gorge and erosion hollows. tion needs of the Upper Soča Valley. The plant utilizes the energy of a strong and permanent karst spring of Where do the waters of Glijun and Boka come from? o Glijun. Soon after the water comes out from the source, Raccol Lag Jerebica ana el ca Glijun is one of the largest karst springs in the area and/R ekl o d 2126 i it flows into a 170m long channel to a water reservoir anica Ri tn ri one of the few if not the only one that never runs dry. o alsoBriceljk known as the Plužna lake. From the lake, the water 12 K 2346 It very quickly responds to rainfall. Its drainage basin ABISSO GOR TANI flows along a one kilometer canal until it reaches a steel 11 covers a large part of the central Kanin Mountain Range, Hudi Vršič pressure pipe and finally falls 66m into the so called I T A L Y 2344 particularly the Kanin Karst Plateau and the slopes below ^RNELSK O BREZNO Francis turbine. The water reservoir is filled or emptied them. The western part of the mountain and the highest Prestreljenik according to the demands for electricity or in relation to Racc 2499 ago Rombon Bav{ki Grintavec olan ČEHI 2el L Jerebica a parts of the Kanin Karst Plateau feed the Boka waterfall. a/R d 2208 ic the water2347 supply. This can significantly lower its water Visoki Kanin eklan SKALARJEVO io 2126 n ica R it Due to the high position of the drainage basin the Boka2587 r level. The installed power of the HEPP Plužna is 1.720 BREZNO ns VANDIMA o Briceljk 12 ai K 2346 arises around fourteen days later than GlijunR in the spring ABISSO GORntTANI MW with an annual production of 5,300 MWh. es ou 11 time. The average discharge of Glijun iisa about 0.5m3/s, M Hudi Vršič /R T he IKTaAniLnY 1 ez 2344 the lowest is about five times smaller. The ijaverage annual ^RNELSK O BREZNO Underwater canal of the Plužna accumulation lake a Velika Baba Prestreljenik 4 5 3 2 temperature of the spring water is about 6°C. 2137 2499 Rombon Soča Bav{ki Grintavec MALA BOKA ČEHI 2Bovec 2208 2347 Vrh Planje Visoki Kanin 8 SKALARJEVO 2587 BREZNO6 s in Characteristics of the spring water 1663 Slap Boka 7 ain VANDIMAas R 9 10 nt B es u ec Even in the coldest and most dry winter, moreia than Mo T he B ov / T h anin Javoršček1 Učja Re e K hundred liters of water flow flows into the Glijun zspringij Učja 1557 a Velika Baba 4 5 3 2 every second. Its average temperature is the highest at this 2137 Žaga MALA BOKA Bovec Soča time of year (+7°C), whereas the spring and summer waterVrh Planje 8 n 1663 Slap Boka S 7 L6 O V E N Is i A is about 2°C lower. The reason for this paradox lies in the 9 10 B a T h B ovec fact that a thick layer of snow on the Kanin Karst Plateau e KrasjiJavoršček vrh Učja 1773 Učja 1557 begins to melt and the snowmelt causing the water of Kobariški Stol the spring to cool down. The snow can remain well into 1673 Žaga the summer, especially in karst depressions, kotliches and S L O V ESoča N I A Breginj chasms. Boka runs dry completely in the winter, since its Srpenica Krasji vrh Krn cold drainage basin in the high karst terrain is filled up 1773 Precipitation map of Slovenia in the Kobariški Stol with snow and does not let even a drop of water flow into 1673 period from 1961 to 1990 (ARSO, 2014) diža Soča the depths. Na Kobarid Breginj Water canalKrn of the HE Plužna When the water gates open Strong precipitation is a common phenomenon in the Map of the Kanin mountain range with the positions of some Kanin adiža Kobarid Bovec region. Autumnal rainfallZbor41.qxd can be as high 25.3.2002 as 300mm 11:05 PageN 12 chasms and karst springs at the southern foot of the range (according per 24 hours. When this occurs, many new water sources to B. Komac, 2001). The map shows a significant difference in the arise, jointly creating various sounds like a small water number of karst springs on the southern and northern side of the orchestra. Before the bridge above the gorge of Glijun Izviri: KarstKanin springs: mountain range. and right before the Plužna accumulation lake, water The limestone pavement on Skripi below Tomažek Tomažek rushing from all sides strengthens the flow of the Glijun Bla` Komac,1 The karst springs of the Kanin massif 1 the D station of the Kanin cableway and creates thundering sounds. 2 GeIzviri:reš 2KarstGe springs:reš (2100m) is covered with rinnenkarrren. Racc UbivnicaToamagožek UbToimavnicažek olan 3 1 el L Jerebica a 31 a/R d ic The orchestra of sources ekla io 2126 n nica R Gereš t Gereš 4 Glijun2 ri 42 Glijun Water also springs out from the cave of Srnica lying in o Briceljk 12 3 Ubivnica K 3 Ubi2346vnica the valley head at the end of the valley of Glijun. Srnica ABISSO GORTANI5 Kladenki 5 Kladenki 4 Glijun 11 4 Glijun is one of the strongest occasional sources in the area. Its Hudi 6Vr{i~Vodica 6 Vodica I T A L ITALYY 2344 Karst springs: approximately 750m long tunnels on several floors are 5 Kladenki^RNELSKO BREZNO 5 Kladenki completely dry most of the year. With heavy rainfall, its Prestreljenik 7 Žvika 7 Žvika 2499 6 Vodica Rombon 61Bav{kiVoToma`ekdica Grintavec Boka^EHI 2 Boka tunnels are quickly flooded by water flowing to the lowerVisoki Kanin 8 2208 8 2347 SKALARJEVO 7 Žvika 72 ŽvGere{ika and upper entrance. From the upper entrance a 35m high 2587 BREZNO Bočič s VANDIMA Bočič 9 8 iBokan 98 Boka and very narrow waterfall occurs. This usuallyR happens ta 3 Ubivnica es un ia Mo10 Izvir9 priBočič Bočiču 109 SpBočičring at Bočič after several days of rain, only once a year and /lastsR only The Kanin 1 4 Glijun ez for a few hours. In the year of 1999 the water occurredija 11 M1o0žnica5 Izvir pri Bočiču3 2 1110 MSpožnicaring at Bočič Velika Baba 4 5 Kladenkio~a several times. After such exceptional years, a year or two 2137 Možnica Možnica S MALA12 BOKAGo11riuda 1211 Goriuda without this phenomenon can follow. With each periodVrh Planje Bovec 6 Vodica 8 612 Goriuda in 12 Goriuda 1663 Slap Boka 7 Jama as Shaft, cave of heavy rain, water starts to flow down the slope of the 9 10 c B 7 @vika waterfall and the nearby karstic torrent Krničar. The JamaThe Bove Shaft, cave U~ja Javor{~ek 8 Boka permanent source of Krničar appears in the lowest part U~ja 0 1 2 3 4 km 1557 0 1 2 3 4 km 0 1 2 3 4 km 0 9 1 Bo~i~2 3 4 km of its bed, not far away from its confluence with Glijun. @aga Kartograja: Jerneja Fridl Cartography: Jerneja Fridl © GeogrKaafskirtog inštituraja: JterAMneja Z FRridlC SAZU © CaGeor10toggrrafskiapSpringhy :inštituJerne jatat F AMBo~i~ridl ZRC SAZU S© Geo LgrafskiO inštituVt AM ZERC SAZU N I A © Geografski inštitut AM ZRC SAZU Srpenica Krasji vrh 11 Mo`nica 1773 Goriuda Kobari{ki Stol 12 1673 S Shaft, cave o ~ Breginj a Krn 0 1 2 3 4 km

a Cartography: Jerneja Fridl di` Na Kobarid © Geografski in{titut AM ZRC SAZU

Figure 2: The location of karst springs, caves, and shafts in the Kanin massif. Slika 2: Polo`aj kra{kih izvirov, jam in brezen na Kaninskem pogorju.

sitional as it forms a part of the alpine »hydrogeographical roof« and contributes waters to three rivers and two seas. It is bordered by the Mo`nica and Koritnica valleys in the northeast and east and by the So~a Valley in the south. On the west it is bordered by the Uccea (U~ja) Valley, the Idrija fault zone, and the valley of the Resia (Rezija) River that flows into the Tagliamento (Tilment) River. The Raccolana (Reklanica) and Rio del Lago (Jezernica) valleys that form the northern boundary of the Kanin massif run along the Raccolana fault zone.

Due to their copiousness and constancy, the waters of the Kanin massif have been always important for the residents of the Bovec Basin for survival (drinking water), practical (protection from pollution and floods), economic (hydroelectric power), and symbolic reasons.

Since the quantity of water is limited and a great part of it is not accessible, great caution is necessary in planning the exploitation of water resources. For this reason, researchers have intensively studied the catch- ment areas of Kanin’s karst springs for decades to determine the minimum discharges that will provide a sufficient water supply and the extent and permeability of the karst bedrock.

2. Geological structure

The first geological research of the Kanin massif was undertaken in the middle of the 19th century. Initially, a broad geological survey of this contact area between the Southern Alps, the Inner Dinarides, and the Outer Dinarides was done primarily for strategic reasons, and later research was done to locate mineral resources and sources of drinking water and electric energy.

12