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River

Olza

99 km from source to mouth · Poland and Czechia.

PolandCzechiaPoland and CzechiaFlows into Oder

Follow the riverMonth by month

SourceMouth
The river and every tributary in its basin, drawn from RiverATLAS (CC BY 4.0).

In numbers

Length

99km

Average flow

52m³/s

Basin

1,118km²

Drop

195m

from 383 m to 188 m

Countries

2

The journey

From source to mouth

99 km of river and 54 stops on the way: 32 towns and cities on its banks, dams, bridges and the tributaries that feed it.

383 m188 m
Sourceat 383 m0 km
Jaworzynka3,109 people8 km
Lomnátributary21 km
Hluchovátributary30 km
Třinec33,523 people37 km
Cieszyn33,958 people49 km
Darkovské moře0.3 km²62 km
Karviná48,937 people65 km
Petrůvkatributary77 km
Stupeň u Bezdínků, řeka Olše79 km
Kališčák0.4 km²92 km
Oderat 188 m99 km
02040608099 km
  1. 0 kmSourceat 383 m
  2. 0 kmKoniaków3,584 people
  3. 3 kmIstebna4,895 people
  4. 8 kmJaworzynka3,109 people
  5. 12 kmBukovec1,391 people
  6. 15 kmPísek1,884 people
  7. 19 kmPísečná1,073 people
  8. 20 kmJablunkov5,225 people
  9. 21 kmLomnátributary
  10. 21 kmNávsí3,906 people
  11. 23 kmMilíkov1,325 people
  12. 27 kmHrádek1,917 people
  13. 29 kmBystřice5,262 people
  14. 30 kmHluchovátributary
  15. 30 kmKopytnátributary
  16. 35 kmVendryně4,511 people
  17. 37 kmTřinec33,523 people
  18. 43 kmRopice1,752 people
  19. 44 kmPuńców1,508 people
  20. 47 kmSport footbridge in Cieszyn
  21. 48 kmLiberty Bridge
  22. 48 kmČeský Těšín25,750 people
  23. 49 kmFriendship Bridge
  24. 49 kmCieszyn33,958 people
  25. 54 kmChotěbuz1,412 people
  26. 56 kmFootbridge Sousedská lávka
  27. 56 kmPogwizdów3,449 people
  28. 59 kmKaczyce3,056 people
  29. 62 kmDarkovské moře0.3 km²
  30. 63 kmBridge of tř. 17. listopadu over the Olza
  31. 63 kmMost Sokolovských hrdinů (Darkov)
  32. 63 kmDarkov363 people
  33. 65 kmKarviná48,937 people
  34. 66 kmStonávkatributary
  35. 69 kmDoubrava1,125 people
  36. 71 kmBridge of road I/67 over the Olza in Koukolná
  37. 73 kmweir Koukolná
  38. 73 kmRailway Bridge Závada, Petrovice u Karviné
  39. 74 kmDětmarovice4,512 people
  40. 76 kmGołkowice3,582 people
  41. 77 kmStupeň Před Mlýnkou, řeka Olše
  42. 77 kmPetrůvkatributary
  43. 77 kmGodów1,922 people
  44. 79 kmStupeň u Bezdínků, řeka Olše
  45. 81 kmŁaziska1,689 people
  46. 81 kmBalvanitý jez
  47. 83 kmWeir Věřňovice (7,4 km)
  48. 83 kmGorzyczki2,088 people
  49. 83 kmD1 Motorway bridge over the Olše river near Věřnovice
  50. 84 kmSzotkówkatributary
  51. 90 kmBohumín20,315 people
  52. 92 kmStarý Bohumín23,034 people
  53. 92 kmKališčák0.4 km²
  54. 92 kmChałupki1,697 people
  55. 96 kmOlza1,699 people
  56. 99 kmOderat 188 m

Water level along the river (RiverATLAS; the height is exaggerated). Towns: GeoNames and Wikidata; bridges, dams and tributaries: Wikidata.

River in Central Europe, tributary of the Oder

At the mouth it carries 52 m³/s on average: an Olympic pool every 48 seconds. It drops from 383 m to 188 m, 2.0 m per kilometre on average. Its basin covers 1,118 km², about the size of MQ. 1.5 million people live in it. Highest water: May; lowest: from December to February. Dams and reservoirs hold back a large share of its water (21% of a year's flow).

Read more on Wikipedia

Where to start

  • KarvináLargest city on its banks · 48,937 people
  • Leoš Janáček Airport Ostrava (OSR)Nearest airport with scheduled flights, 36 km from the cityCar hire at OSR airport (Mošnov)Discover Cars · Affiliate link
  • On the water4 ferry piers, marinas, boat rentals and boat ramps along the river (OpenStreetMap)
  • Kayak and canoe1 put-ins and rapids mapped (OpenStreetMap)
  • From May to SeptemberThe best months to visit

Olza, month by month

Highest water: May

Lowest water: from December to February. Best months to visit: from May to September.

43
-3°30 mmJan
32
-1°30 mmFeb
87
4°35 mmMar
90
9°50 mmApr
100
13°82 mmMay
84
17°98 mmJun
90
18°94 mmJul
89
18°86 mmAug
79
14°59 mmSep
70
10°43 mmOct
67
4°46 mmNov
53
0°38 mmDec
Water (estimated flow)Air (average) Rain (mm)Best months

From about 32 m³/s in the lowest month to 100 m³/s in the highest. An estimate: the monthly flow is modelled from the lowest and highest months of WaterGAP (RiverATLAS, 1971–2000) and the rain and snow along the river (WorldClim). Dams change the real rhythm. The chip is the average air temperature; below it, the month's rain.

Plan the trip

Plan the trip: boat trips, a bed by the river, a car

Car hire at OSR airport (Mošnov)Discover CarsSee 

Some links above are affiliate links: if you book through them we may earn a commission, at no extra cost to you. It never changes what the data on this page says.

The basin

Olza: the basin in numbers

5,823 km² of land send their water to this river. This is what lives on it.

Heavily regulatedReservoirs can hold 21% of a year's flow: dams shape its seasons.
  • 1.5millionpeople live in the basin
  • 252/km²people per km²
  • 450maverage altitude of the basin
  • 754mmof rain a year (basin average)
  • 7.2°Caverage air temperature
  • 17%protected areas
  • 0.5%covered by lakes
  • 0.3km³held in reservoirs

What covers the basin

  • 44% Forest
  • 38% Cropland
  • 12% Pasture
  • 17% Towns and cities

RiverATLAS (HydroATLAS v1.0, CC BY 4.0): land cover, people, protected areas, glaciers and dams over the whole basin upstream of the mouth.

Along the river

Olza: what you find on the way

  • 2Dams
  • 88WeirsKaskady, III jaz and 86 more
  • 1LocksŽidovský hřbitov v Jablunkově
  • 1Waterfalls
  • 1Rapids
  • 4MarinasPomost betonowy - Zabełków - 718,2 LB and 3 more
  • 1River beaches

From OpenStreetMap, within 1.7 km of the river. Not mapped is not the same as not there.

Cross-checked with our atlases

Olza in our other atlases

What our sister atlases know about the waterfalls on this river, the lakes it flows through, the beaches at its mouth, the mountains where it rises and the islands off its mouth.

  • 2lakes on its wayLakeyas
  • 54mountains at the sourcePeakyas

Lakes and reservoirs (2)

Lakes it flows through, by Lakeyas

  1. Darkovské mořekm 520.3km²
  2. Kališčákkm 770.4km²

Lakeyas is coming soonOpen Lakeyas ↗

Mountains at the source (54)

Within 15 km of the source, by Peakyas

  1. Barania Góra13 km away · prominence 170 m1,220m
  2. Czantoria Wielka13 km away · prominence 310 m995m
  3. Stożek Wielki5.1 km away978m
  4. Magurka Wiślańska14 km away1,140m
  5. Zielony Kopiec14 km away1,154m
  6. Kikula14 km away1,087m
  7. Kozubová12 km away · prominence 173 m982m
  8. Velký Polom14 km away · prominence 258 m1,067m

46 more on PeakyasOpen Peakyas ↗

From space

The source and the mouth, seen from orbit

Olza: satellite view of the source
The source14 km across
Olza: satellite view of the mouth
The mouth10 km across

Sentinel-2 cloudless 2016 by EOX IT Services GmbH (contains modified Copernicus Sentinel data 2016), CC BY 4.0. The glowing line is the river as drawn by RiverATLAS.

Photos

Olza in pictures

Olše ze Sousedské lávky
Aqalexor · CC BY-SA 4.0
The source of Olza
Pborys · CC BY-SA 4.0
Řeka Olše (Olza) poblíž Vendryňského topolu, Vendryně, okres Frýdek-Místek
Fry72 · CC BY-SA 4.0

Tributaries

Where it flows, and what flows into it

It flows into

OderPolandPoland854 km480 m³/s

Tributaries (12)

Also: Lomná, Petrůvka, Stonávka, Tyrka, Hluchová, Ropičanka, Szotkówka, Kopytná, Jasení, Bobrówka, Puńcówka, Jatný potok

In the same basin

WartaPolandPoland808 km200 m³/sLusatian NysaGermanyGermany254 km30 m³/sNotećPolandPoland388 km210 m³/sBóbrPolandPoland272 km44 m³/sNysa KłodzkaPolandPoland195 km45 m³/sObraPolandPoland253 km10 m³/sProsnaPolandPoland216 km18 m³/sDrawaPolandPoland186 km22 m³/sOstraviceCzechiaCzechia55 km160 m³/sNerPolandPoland134 km10 m³/s

Nearby

Rivers nearby

OstraviceCzechiaCzechia55 km160 m³/s11 km awayOpavaCzechiaCzechia111 km16 m³/s16 km awaySołaPolandPoland89 km19 m³/s71 km awayNysa KłodzkaPolandPoland195 km45 m³/s106 km awayBečvaCzechiaCzechia62 km18 m³/s94 km awayOravaSlovakiaSlovakia60 km340 m³/s109 km awayMoravaAustriaAustria388 km110 m³/s180 km awayDunajecPolandPoland274 km84 m³/s177 km away

Where these numbers come from

Name, length, placesWikidata (Q1331973) · CC0
Course, profile, basinRiverATLAS v1.0 (HydroATLAS, Linke et al. 2019) · CC BY 4.0 — followed from the source to the mouth given by Wikidata
FlowWaterGAP (RiverATLAS), 1971–2000 · CC BY 4.0
Climate along the riverWorldClim (RiverATLAS), 1970–2000 · CC BY 4.0
Towns, bridges, damsWikidata · CC0; GeoNames · CC BY 4.0
Along the river© OpenStreetMap contributors · ODbL
ImagesEOX Sentinel-2 cloudless 2016 · CC BY 4.0; Wikimedia Commons
Our other atlasesLakeyas, Peakyas — Wikidata · CC0; © OpenStreetMap contributors · ODbL; GeoNames · CC BY 4.0; HydroLAKES · CC BY 4.0; NOAA OISST

Every source and licence is on the data sources page.

The family

Do you prefer beaches, lakes, mountains, waterfalls, islands, rivers or canyons?

Same idea, other landscapes: field atlases built on open data, month by month, in seven languages.

beachesCoastyaFind your beach: sea temperature, sun and swimming month by month.Visit
lakesLakeyasEvery lake on Earth: water temperature, ice, depth and the shore.Coming soonVisit
mountainsPeakyasEvery summit in 3D: summit weather, the 0 °C line, huts and trails.Visit
waterfallsCascadyasEvery waterfall: height, flow month by month and when it roars.Coming soonVisit
islandsIslandyasEvery island from the sea up: size, sea temperature, ferries and 3D.Coming soonVisit
riversRiveryasEvery river from source to sea: the journey, the flow and the basin in numbers.You are here
canyonsCanyonyasEvery canyon cut to scale: depth to the floor, rim and floor temperatures, trails and viewpoints.Coming soonVisit