The project is co-funded by the European Union,

Instrument for Pre-Accession Assistance

Test area of Kobariški stol, Mija and Matajur aquifers, Slovenia

(This report is prepared by FB5 DRINKADRIA project team at the Faculty of National Sciences and Engineering as a contribution to DRINKADRIA project implementation activities for WP4)

assist. dr. Petra Žvab Rožič assist. prof. dr. Barbara Čenčur Curk prof. dr. Boštjan Rožič prof. dr. Timotej Verbovšek prof. dr. Amdrej Šmuc

Ljubljana, February 2015

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Table of contents

1. BASIC DATA ABOUT TEST AREA ................................................................................................................. 3

1.1. Geographical position ...................................................................................................................... 3

1.2. Morphological description ............................................................................................................... 3

1.3. Climate characteristics ..................................................................................................................... 3

1.4. Geological description ...................................................................................................................... 4

1.5. Pedology ........................................................................................................................................... 5

1.6. Hydrogeology ................................................................................................................................... 5

1.7. Drinking water protection areas ...................................................................................................... 5

2. WATER SUPPLY OF THE TEST AREA ........................................................................................................... 8

3. MAIN IDETIFIED PROBLEMS .......................................................................................................................... 8

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1. BASIC DATA ABOUT TEST AREA

The test area of FB5 project partner covered the Kobariški stol, Mija and Matajur aquifers which present cross-border aquifers on Slovenia-Italy border. These three aquifers have been selected as test area for WP4 contribution as potential sources of drinking water for the future. While detail borders of aquifers have not been yet determined, the data and descriptions are presented together for the whole area covering all three aquifers.

1.1. Geographical position

Investigated aquifers are located in Northern Primorska region on the north-western part of Slovenia border with Italy (Figure 1). They cover the mountain ranges called Kobariški stol, Mija and Matajur that are extending from the city of Kobarid and village Livek towards the west into Italy to the village of Pradielis and Musi.

Figure 1: Geographical position of the Slovenian test area

1.2. Morphological description

The majority of the test area has the character of the mountainous morphology, only in the northernmost and southernmost part the aquifer the slope is gradually decreasing into alluvial plane of the Učja and Nadiža rivers. The main springs are located at the base of the mountain range, near the transition into alluvial plane. Only in rare cases (only in the north-facing slopes of Mt Kobariški stol springs are in the middle of the slope.

1.3. Climate characteristics

The data describing the climate characteristics of test area are based on national monitoring data (http://meteo.arso.gov.si/). For evaluating regional climate and climate changes, two mean meteorological stations (Bilje and Portorož) were used due to sufficiently long series of

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temperature and precipitation data. To characterise more local climate of test area we chose closer station with shorter data series. For precipitation data three meteorological stations (Kobarid, Livek, Žaga) were selected that cover most of the test area with its positions. The closest temperature meteorological station is Vogel which was selected for the most locally representative station.

The Vogel meteorological station (46° 15’ 50’’ °N, 13° 50’ 44’’ °E) is positioned 1535 m above the see level within Vogel ski centre on the Bohinj ridge, a mountain ridge between Primorska and Gorenjska region in north-western Slovenia. Temperature measurements on this station starts in 1982, while due to complete data series the results represent the annual average temperature for the period 1987-2014. The mean annual temperature at this station varies between 3.60 and 6.12°C, on average 4.89 °C. The coldest months are February with average temperature -2.62 °C and the warmest August with 13.77 °C.

Meteorological stations for precipitation data are positioned at different elevations within the test area: Kobarid (46.3 °N, 13.6 °E, 263 m), Livek (46.2 °N, 13.6 °E, 695 m) and Žaga (46.3 °N, 13.5 °E, 353 m). Locations Kobarid and Žaga are located in the Soča vally and station Livek higher on the Matajur slope. Observation period of precipitation data is from 1961 to 2013. The mean annual precipitation at Kobarid location is 2681.1 mm (1596.0 – 4354.2 mm), Livek 2543.8 mm (1496.8 – 3679.8 mm) and Žaga 2964.6 mm (1828.0 – 4041.5 mm). Data from all locations show the highest average precipitation in November and the lowest in February.

1.4. Geological description

The investigated area structurally belongs to the contact area between External Dinarides and Southern Alps, more exactly to the Trnovo Nappe and Tolmin Nappe respectively (Placer, 1999, 2008). The Kobariški stol belongs to the Tolmin Nappe, whereas the Mija-Matajur successions belong to the Dinarides and form large-scale anticline (Buser, 1986, 1987). Paleo-geographically, In the Upper Triassic and Lower Jurassic it belonged to the transitional area; i.e. shallow water bridge between the Dinaric Carbonate Platform to the south and Julian Carbonate Platform to the north. Eastward of this area, the Slovenian Basin was opening (Buser, 1989). In the Middle Jurassic the Julian Carbonate Platform drowned and became pelagic plateau known as the Julian High (Buser, 1989; Šmuc, 2005; Šmuc and Rožič, 2010). Drowning affected also the investigated area and solely on the Mija-Matajur succession the shallow-water environments re-established in the latest Jurassic (Buser, 1989; Turnšek, 1997). In the Upper Creataceous the entire region exhibits deep-water sedimentation (Buser, 1986).

The basic geological characteristics are presented on gelogical map in Figure 2. The oldest rocks of the investigated area belong to the Norian-Rhaetian Dachstein limestone, which exhibits typical lofer cycle. These deposits are overlain by a Lower Jurassic platform limestone with Lithiotis-type bivalves and ooidal/crinoidal limestone (Buser, 1986). The overlying Middle/Upper Jurassic deposits are represented by even bedded and later nodular fine-grained limestone with intercalated calciturbidites (Miklavič and Rožič, 2008; Šmuc, 2012). On Mija, this formation passes upwards into late Upper Jurassic shallow-water reef limestone, which becomes younger towards west (Buser, 1986; Turnšek, 1997). Simultaneous sedimentation on Kobariški stol is characterized by the red nodular limestone of Rosso Ammonitico type that is overlain by micritic limestone of the Biancone type (Šmuc, 2012). Upper Cretaceous of the entire area is characterized firstly by Volče limestone, which is thin bedded pelagic and calciturbiditic limestone with chert nodules (Buser, 1986, 1987). The entire succession ends with the latest Cretaceous Upper Flyschoid Formation, which begins with basal limestone breccia overlain by marls alternating with siliciclastic and carbonate turbidites (Buser, 1986).

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Figure 2: Geological map of the Kobariški stol, Mija and Matajur aquifers (Buser, 1986)

1.5. Pedology

Characteristics of the soil of test area are highly related to the carbonate karst terrain, which represents a large part of the investigated area. The soil on karst terrain is mostly very poorly developed and, consequently the area is less cultivated. Within test area agricultural land is mainly related to riverine plains, where different types of soils on river sediments are developed. The following types of soil are in the study area: leptisols (redzic, mollic, lithic), cambisols (dystric, eutric), calcaric regosols, calcaric fluvisol, eutric gleysol.

1.6. Hydrogeology

Geology and hydrogeology of the investigated aquifers are generally uniform. There are karst aquifers composed predominantly of very thick succession of bedded platform carbonates, mostly limestone of Late Triassic and Lower Jurassic age. The lithological differences occur only in the topmost, relatively thin, Upper Jurassic to Late Cretaceous part, composed of laterally diminishing and reappearing thin-bedded limestone with chert, nodular limestone and limestone breccia. As these are limestone varieties, their hydrogeological characteristic remain karstic and form a minor portion of the large aquifers. Aquifer barriers are formed by end Cretaceous and Paleogene flysch deposits, whereas contacts are tectonic as well as stratigraphic. Within the flysch, limestone breccia megabeds form small-scale isolated aquifers.

1.7. Drinking water protection areas

There are several water sources within the test area that are captured for drinking water. Some of them were classified as water protection areas (WPA) as presented on Figure 3. In this area water sources are protected on municipal level with the Decree on determination of drinking water protection areas and measures for protection of drinking water source Repec at Breginj and Decree on determination of drinking water protection areas and measured for protection of drinking

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water source Livek (Slovenian Official Gazette 26/2000). These water sources are used for drinking water supply, which is implemented as a public service. However, in the test area there are several other drinking water sources, which are not protected, although they are used for water supply for own purposes or public service.

Figure 3: The map of drinking water protection areas on municipal level

1.6 Land use description

Description of land use was done based on the available CLC data from 2012 (Figure 4). In this report the proportions of land uses are presented at 1st level division of CLC land use categories. Most of the test area is covered by forest and semi natural areas (85.27 %) in greatest extent broad-leaved forest. Agricultural areas (14.56 %) include the areas along the streams (heterogeneous agricultural areas along Nadiža, Soča) and pastures in mountains, where the pastoralism is developed. Artificial areas (0.28 %) are over the settlements, among which the largest is Kobarid.

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Figure 4: The map of land use on the test area (CLC, 2012)

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2. WATER SUPPLY OF THE TEST AREA

Within the test area drinking water is supplying by the public water utility Tolmin. There are laso private water supplies and individual water supplies. Public water utility Tolmin covers with water supply three municipalities, including the municipality of Kobarid, in which a predominant part of the investigating area is located. Within the municipality of Kobarid 91% of population are supplied by the drinking water from public water supply, while the rest is supplies by its own water supply.

3. MAIN IDETIFIED PROBLEMS

Settlements within the test area are sparsely and highly dispersed, resulting in a diversified abstraction of drinking water. Part of the inhabitatants are connected to the public water supply, part of the inhabitants have own water supply. The consequence of this is poor control of the amount of water abstracted, as well as control of drinking water quality (monitoring) in own water sources. Despite the fact that the state of drinking water is good due to the natural characteristics of the catchment area and scattered population, locally contamination can occur due to economic use (agriculture, grazing). Regarding available data of Environmantal Atlas of Slovenia only for two drinking water sources in the test area are water protection areas (WPA) are determined (Figure 3). The recharge areas of other water sources (used for own or public supply) are not protected.

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4. TEST AREA SUMMARY TABLE

The main characteristics of the test area are shortly presented in Table 1. Table 1: Summary table of test areas in Slovenia

Name of test

area Kobariški stol, Mija and Matajur aquifers (Figure 1)

WR 1 aquifer system, 3 aquifers

Related City* Kobarid (46.248 °N, 13.579 °E)

Geographical

coordinates 46.319 °N – 46.167 °N, 13.375 °E – 13.740 °E

Altitudinal

range 152 – 1648.4 m (687.2 m)

Size 163 km2

Morphology Mostly mountains, alluvial plane of Učja and Nadiža river

Aquifer type Karstic

Surface water

interaction Unknown

Geology Triassic to Upper Cretaceous Limestone, Upper Flyschoid Formation

(Figure 2)

Mean annual

precipitation

Meteorological station Kobarid 2681.1 mm (1596.0 – 4354.2 mm), Livek

2543.8mm (1496.8 – 3679.8 mm) and Žaga 2964.6 mm (1828.0 – 4041.5

mm)

Mean annual

temperature Meteorological station Vogel: 4.89 °C (3.60 - 6.12°C)

Soil types Predominant soils on carbonate rocks; leptisols (redzic, mollic, lithic),

cambisols (dystric, eutric), calcaric regosols, calcaric fluvisol, eutric gleysol

Land uses Artificial areas (0.28 %), Agricultural areas (14.56 %), Forest and semi

natural areas (85.27 %) (Figure 4)

Protection

areas Water protection zones: WPA I, WPA II, WPA III (Figure 3)

Water

abstraction No data

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*Cities and rural settlements receive their drinking water supply from the test area.

5. REFERENCES

Buser, S., 1986: Tolmač k Osnovni geološki karti SFRJ 1: 100 000 lista Tolmin in Videm (Udine).

Zvezni geološki zavod, Beograd,pp.103

Buser, S., 1987: Osnovna geološka karta SFRJ 1: 100 000, list Tolmin. Zvezni geološki zavod,

Beograd

Buser, S., 1989: Development of the Dinaric and Julian carbonate platforms and the intermediate Slovenian basin (NW-Yugoslavia). in: Carulli, G.B., Cucchi, F. & Radrizzani, C.P. (ed.): Evolution of the Karstic carbonate platform: relation with other periadriatic carbonate platforms. Mem. Soc. Geol. Ital., 40 (1987), Roma, 313–320

Miklavič, B., Rožič, B., 2008: The onset of Maastrichtian basinal sedimentation on Mt. Matajur, NW

Slovenia. RMZ - Materials and geoenvironment, 52, 199–214

Odlok o določitvi varstvenih pasov in ukrepov za zavarovanje vodnega zajetja Repec pri Breginju (Decree on determining protection zones and measures for protection of water catchment Repec pri Breginju). Official gazette of republic of Slovenia No. 26/2000.

Odlok o določitvi varstvenih pasov in ukrepov za zavarovanje vodnih zajetij vodovoda Livek (Decree on determining protection zones and measures for protection of water catchments of waterworks Livek). Official gazette of republic of Slovenia No. 26/2000.

Placer, L., 1999: Contribution to the macrotectonic subdivision of the border region between

Southern Alps and External Dinarides. Geologija, 41, 223-255

Placer, L., 2008: Principles of the tectonic subdivision of Slovenia. Geologija, 51, 205–217

Šmuc, A, 2005: Jurassic and cretaceous stratigraphy and sedimentary evolution of the Julian Alps,

NW Slovenia. Založba ZRC, ZRC SAZU, Ljubljana, pp.98

Šmuc, A., 2012: Middle to Upper Jurassic succession at Mt Kobariški Stol (NW Slovenia). RMZ -

Materials and geoenvironment, 59, 267-284

Šmuc, A., Rožič, B., 2010: The Jurassic Prehodavci Formation of the Julian Alps: easternmost

outcrops of Rosso Ammonitico in the Southern Alps (NW Slovenia). Swiss journal of geosciences,

103, 241-255

Turnšek, D., 1997: Mezosoic Corals of Slovenia.- Založba ZRC, Ljubljana, pp.512

Internet data sources:

http://meteo.arso.gov.si/

http://gis.arso.gov.si/geoportal/catalog/main/home.page

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The project is co-funded by the European Union,

Instrument for Pre-Accession Assistance