Veľká Kolpašská nádrž

Geological structure beneath the water

Which rock lies beneath the water line (Geological Map of Slovakia 1:50,000), how old it is, how thick the Quaternary cover is and in which tectonic unit the water flows. The bedrock decides the hardness of the water, the bottom, the turbidity after rain and the abundance of springs.

The points follow the water line (for a stream and a basin, fishing district after fishing district). The strip is a cross-section by distance, not a map; the width of a section corresponds to the number of points.

• River alluvium100%SR 72 %

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River alluvium: Gravelly and sandy bottom and floodplains; the water is replenished from groundwater in the alluvium.

Geological age of the rocks

• Quaternary100%

Most common rock units

Quaternary cover

• Typical thickness of the Quaternary cover3.5m

• 2 – 5100%SR 48 %

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Tectonic division

• NEOALPÍNSKE TEKTONICKÉ ŠTRUKTÚRY ZÁPADNÝCH KARPÁT100%SR 84 %

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Neotectonic units

• positive unit (mountain range)100%SR 60 %

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Direction of neotectonic movements

• large uplift100%SR 26 %

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Regional geological division

• neovolcanic rocks100%SR 10 %

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Regional geological division (subunits)

• Central Slovak neovolcanic rocks100%SR 8.8 %

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Susceptibility of the area to slope deformations

• Region of stable areas100%SR 95 %

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The map covers 1 of 1 points on the water line.

Hydrogeology: aquifers and groundwater

Streams and rivers are fed by groundwater. Hydrogeological maps show in which rocks the water is stored, how permeable they are and what the water in them is like. The data come from ŠGÚDŠ maps, not from measurements at a particular water.

Aquifer rocks (hydrogeological map 1:200,000)

• Acid volcanic rocks100%SR 3.2 %

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Aquifer type

• Menšie zvodnence s medzizrnovým alebo puklinovým typom priepustnosti alebo oblasti s takmer žiadnymi množstvami podzemnej vody100%SR 3.2 %

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Surface water chemistry according to the atlas

Modelled composition of the water in the area the fishing district line runs through. The rasters of the Geochemical Atlas of Slovakia (surface waters) are an interpolation of measurements in sampled streams, so they show the typical background of the area, not a measurement in a particular stream.

Ionic composition of the water

Water type by dominant ions: Ca–HCO₃–SO₄

Shares are in equivalents, the usual way of comparing the composition of waters.

Major ions

• PotassiumK7.58 mg/lpercentile 87
• FluoridesF0.169 mg/lpercentile 72
• SodiumNa11.8 mg/lpercentile 61
• ChloridesCl11.5 mg/lpercentile 56
• SulphatesSO443.3 mg/lpercentile 54
• MagnesiumMg8.93 mg/lpercentile 28
• BicarbonatesHCO3133 mg/lpercentile 27
• CalciumCa34.2 mg/lpercentile 23

dot: average along the water line, line: from the lowest to the highest value, scale: position among sample points on streams in Slovakia (0 to 100th percentile)

Nutrients and organic pollution

• PhosphatesPO42.59 mg/lpercentile 96
• AmmoniumNH43.66 mg/lpercentile 95
• NitratesNO37.11 mg/lpercentile 57
• Chemical oxygen demandChSK3.35 mg/lpercentile 54

Metals

• ZincZn70.7 μg/lpercentile 95
• ManganeseMn128 μg/lpercentile 84
• IronFe0.225 mg/lpercentile 78
• AluminiumAl39.8 μg/lpercentile 36

Elements in river sediments

The Geochemical Atlas of Slovakia (river sediments) describes what the river carries in the fine material on its bed. Sediment collects metals from rocks, ore occurrences and past mining and industry. It is not a legal limit or a health risk assessment: it shows how an element on this stream ranks among streams in Slovakia.

Potentially toxic and trace elements

• CobaltCo22.3 mg/kgpercentile 96
• VanadiumV128 mg/kgpercentile 95
• LeadPb54.0 mg/kgpercentile 95
• CadmiumCd0.838 mg/kgpercentile 92
• ZincZn196 mg/kgpercentile 89
• BismuthBi0.390 mg/kgpercentile 84
• TinSn4.06 mg/kgpercentile 82
• CopperCu35.1 mg/kgpercentile 79
• MolybdenumMo0.482 mg/kgpercentile 67
• MercuryHg0.152 mg/kgpercentile 66
• AntimonySb0.696 mg/kgpercentile 55
• ChromiumCr44.0 mg/kgpercentile 10
• SeleniumSe0.0915 mg/kgpercentile 8
• NickelNi9.45 mg/kgpercentile 4
• ArsenicAs1.65 mg/kgpercentile 1

dot: average along the water line, line: from the lowest to the highest value, scale: position among sample points on streams in Slovakia (0 to 100th percentile)

Natural radioactivity and radon

Airborne gamma-ray spectrometry by ŠGÚDŠ measures radiation from potassium, uranium and thorium in rocks and soil. Granites and some acidic volcanic rocks have the highest values, limestones and floodplains the lowest. Caesium-137 is a remnant of fallout from the Chernobyl accident and nuclear weapons tests.

• Equivalent uranium (eU)eU3.80 ppm95th percentile
• Equivalent thorium (eTh)eTh10.4 ppm95th percentile
• Potassium (K)K1.73 %percentile 92

dot: average along the water line, line: from the lowest to the highest value, scale: position among sample points on streams in Slovakia (0 to 100th percentile)

• Areal activity of 137CsCS1373,475 Bq/m²percentile 91

Radon risk by isopleths

• medium100%SR 64 %

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Geophysical fields: magnetics and gravity

Maps of the magnetic field and gravity (ŠGÚDŠ) reveal what lies beneath the sediments and the surface: volcanic bodies, faults and crustal thickness. For an angler they are interesting indirectly: they show where the bedrock changes, and with it the water.

Geothermal potential

The Atlas of Geothermal Energy of Slovakia records rock temperature and heat flow from the Earth's interior. It is the potential of the area, not the actual warmth of the water in the stream. Specific geothermal boreholes and springs near this water are in the geothermal energy section below.

Relief, climate and soils

A basin is not just water: slope and elevation determine the speed of runoff, climate the temperature and amount of water, and soils what is washed into the stream. The data come from the geomorphological division, climatic-geographical types and soil maps of ŠGÚDŠ.

• Elevation of geomorphological units (from–to)255–877m a.s.l.
• Average elevation of the units556m a.s.l.
• Average slope12.9°
• Average January temperature-5.0°C
• Average July temperature16.5°C
• Annual precipitation850mm

Geomorphological units

• Štiavnica Mountains100%SR 2.2 %

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Geomorphological regions

• Slovak Central Mountains100%SR 9.1 %

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Climatic-geographical types

• mountain climate100%SR 33 %

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Susceptibility of soils to acidification

• soils moderately susceptible to acidification100%SR 25 %

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Soil contamination (map 1:500,000)

• uncontaminated soil, the geogenically determined content of some risk elements reaches limit values A100%SR 45 %

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Lithogeochemical types

• Neogene volcanics100%SR 11 %

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Map of the corridor

Where the nearest mine workings, deposits, burdens, geothermal boreholes and gold finds are. Groups can be switched off.

Gold and ore minerals in river sediments

Regional panning prospecting: the heavy fraction was washed out of river gravel and the mineral grains in it were counted. The map of finds is positive: a sample without gold is not listed in the atlas, so the absence of a find is not proof that there is no gold.

• Barite (BaSO₄)4 samples, at most 55 grains
• Ilmenit (FeTiO₃)4 samples, at most 1815 grains
• Magnetite (Fe₃O₄)4 samples, at most 4115 grains
• Pyrite (FeS₂)4 samples, at most 55 grains
• Anatas (TiO₂)2 samples, at most 55 grains
• Rutil (TiO₂)2 samples, at most 315 grains
• Sphalerite (ZnS)2 samples, at most 5 grains
• Galena (PbS)1 sample, at most 50 grains
• Hematite (Fe₂O₃)1 sample, at most 55 grains
• Limonite (FeO(OH)·nH₂O)1 sample, at most 5 grains

Rock-forming and accessory minerals

• Amfiboly (Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂)4 samples, at most 1815 grains
• Pyroxény ((Mg,Fe,Ca)₂Si₂O₆)4 samples, at most 1815 grains
• Zirconium (ZrSiO₄)4 samples, at most 315 grains
• Apatit (Ca₅(PO₄)₃(F,Cl,OH))3 samples, at most 55 grains
• Granáty ((Fe,Mg,Ca,Mn)₃Al₂Si₃O₁₂)3 samples, at most 1815 grains
• Korund (Al₂O₃)3 samples, at most 15 grains
• Sillimanit (Al₂SiO₅)2 samples, at most 55 grains
• Andaluzit (Al₂SiO₅)1 sample, at most 5 grains
• Epidot (Ca₂(Al,Fe)₃Si₃O₁₂(OH))1 sample, at most 315 grains
• Kyanit (Al₂SiO₅)1 sample, at most 55 grains
• Staurolit (Fe₂Al₉Si₄O₂₃(OH))1 sample, at most 315 grains

Groundwater: chemistry, water types and radioactivity

Hydrogeochemical objects (analyses of springs and boreholes), the geochemical atlas of groundwater (1996) and radiohydrochemical sampling. Groundwater feeds streams, so its composition also affects the water in the stream.

Metals in groundwater

• ChromiumCrhigh (top 5 %)
  highest 4.90 μg/lmedian 0.250 μg/l11 samples82 % below the limit of quantification
  1. up to 50 %
  2. 50–75
  3. 75–90
  4. 90–99
  5. above 99

  Highest value: prameň, 960 m from the water. Comparison: percentile 96 of all samples in Slovakia.

• ArsenicAshigh (top 5 %)
  highest 5.80 μg/lmedian 1.00 μg/l11 samples18 % below the limit of quantification
  1. up to 50 %
  2. 50–75
  3. 75–90
  4. 90–99
  5. above 99

  Highest value: prameň1991, 3.0 km from the water. Comparison: percentile 96 of all samples in Slovakia.

• CopperCuelevated (top 10 %)
  highest 3.90 μg/lmedian 0.700 μg/l11 samples
  1. up to 50 %
  2. 50–75
  3. 75–90
  4. 90–99
  5. above 99

  Highest value: prameň1991, 2.3 km from the water. Comparison: percentile 90 of all samples in Slovakia.

• AluminiumAlslightly elevated
  highest 0.0300 mg/lmedian 0.0100 mg/l11 samples18 % below the limit of quantification
  1. up to 50 %
  2. 50–75
  3. 75–90
  4. 90–99
  5. above 99

  Highest value: prameň1991, 1.3 km from the water. Comparison: percentile 85 of all samples in Slovakia.

• LithiumLislightly elevated
  highest 16.0 μg/lmedian 2.00 μg/l11 samples27 % below the limit of quantification
  1. up to 50 %
  2. 50–75
  3. 75–90
  4. 90–99
  5. above 99

  Highest value: prameň1991, 3.0 km from the water. Comparison: percentile 75 of all samples in Slovakia.

• LeadPbslightly elevated
  highest 1.00 μg/lmedian 0.500 μg/l11 samples91 % below the limit of quantification
  1. up to 50 %
  2. 50–75
  3. 75–90
  4. 90–99
  5. above 99

  Highest value: prameň, 960 m from the water. Comparison: percentile 75 of all samples in Slovakia.

• ZincZntypical value
  highest 25.0 μg/lmedian 2.00 μg/l11 samples36 % below the limit of quantification
  1. up to 50 %
  2. 50–75
  3. 75–90
  4. 90–99
  5. above 99

  Highest value: prameň1991, 2.8 km from the water. Comparison: percentile 51 of all samples in Slovakia.

• IronFetypical value
  highest 0.00500 mg/lmedian 0.00500 mg/l8 samples100 % below the limit of quantification
  1. up to 50 %
  2. 50–75
  3. 75–90
  4. 90–99
  5. above 99

  Highest value: prameň1991, 2.7 km from the water. Comparison: percentile 50 of all samples in Slovakia.

• CadmiumCdbelow half of Slovakia
  highest 0.250 μg/lmedian 0.250 μg/l11 samples100 % below the limit of quantification
  1. up to 50 %
  2. 50–75
  3. 75–90
  4. 90–99
  5. above 99

  Highest value: prameň1991, 2.7 km from the water. Comparison: percentile 47 of all samples in Slovakia.

• MercuryHgbelow half of Slovakia
  highest 0.100 μg/lmedian 0.100 μg/l11 samples100 % below the limit of quantification
  1. up to 50 %
  2. 50–75
  3. 75–90
  4. 90–99
  5. above 99

  Highest value: prameň1991, 2.7 km from the water. Comparison: percentile 46 of all samples in Slovakia.

• AntimonySbbelow half of Slovakia
  highest 0.100 μg/lmedian 0.100 μg/l11 samples100 % below the limit of quantification
  1. up to 50 %
  2. 50–75
  3. 75–90
  4. 90–99
  5. above 99

  Highest value: prameň1991, 2.7 km from the water. Comparison: percentile 40 of all samples in Slovakia.

• SeleniumSebelow half of Slovakia
  highest 0.500 μg/lmedian 0.500 μg/l11 samples100 % below the limit of quantification
  1. up to 50 %
  2. 50–75
  3. 75–90
  4. 90–99
  5. above 99

  Highest value: prameň1991, 2.7 km from the water. Comparison: percentile 39 of all samples in Slovakia.

Radon in waters

Mine workings, deposits and ore occurrences

Old mine workings outside mining areas (Geofond register), deposits and mining areas, and the metallogenetic map. Gold, silver and other metals near streams can get into sediments and water.

What was mined here (according to the register of old mine workings)

• Au1×
• Ag1×

Types of mining objects

• spoil heap1×
• other type of object1×
• adit1×

Nearest old mine workings

Deposits and mining areas

Ore occurrences in the metallogenic map

Boreholes and Geofond archive reports

Register of hydrogeological boreholes, other boreholes and geothermal boreholes. Each borehole has a report in the Geofond archive (geological profiles, pumping tests, chemical analyses of the water); the report number is in the table.

27 boreholes in the 3 km zone, of which 19 hydrogeological and 8 other; with an archive report number 27.

Borehole depths

• up to 10 m10×
• 10–30 m6×
• 30–100 m1×
• 100–300 m9×
• over 300 m1×

Nearest boreholes

Geothermal energy and mineral waters

Geothermal boreholes (wellhead water temperature, yield, chemical type) and sources of geothermal and mineral waters within 10 km. Data on the use and existence of a borehole come from the Geofond register.

Sources of geothermal and mineral waters

Environmental burdens, landfills and anthropogenic sediments

Recorded environmental burdens (industrial sites, landfills, mining), the register of waste landfills and monitoring of anthropogenic sediments (industrial sludge). It is a list of places, not a measurement of water pollution.

Waste landfills

Landslides and slope deformations

Register of documented slope deformations (Geofond). Landslides by a stream can bring fine material into the water, change the bed and dam the channel.

Types of deformations

• Landslides9×

Degree of activity

• Potenciálny5×
• Stabilizovaný4×

Current state

• SD taken from archival materials, ktorá bola konfrontova7×
• SD zaregistrovaná v rámci terénneho výskumu na úlohe Atlas S1×