| Jizera Izera | |
|---|---|
 The Jizera inŽelezný Brod | |
 | |
| Location | |
| Countries | |
| Regions/ Voivodeships | |
| Physical characteristics | |
| Source | |
| • location | Lázně Libverda/Mirsk, Jizera Mountains |
| • elevation | 984/1,035 m (3,228/3,396 ft) |
| Mouth | |
• location | Elbe |
• coordinates | 50°10′21″N14°42′56″E / 50.17250°N 14.71556°E /50.17250; 14.71556 |
• elevation | 169 m (554 ft) |
| Length | 167.0 km (103.8 mi) |
| Basin size | 2,193.4 km2 (846.9 sq mi) |
| Discharge | |
| • average | 24.3 m3/s (860 cu ft/s) |
| Basin features | |
| Progression | Elbe→North Sea |
TheJizera (Polish:Izera,German:Iser) is ariver in theCzech Republic and for a brief stretch inPoland. It is a righttributary of theElbe River and flows through theLiberec andCentral Bohemian regions. It is 167.0 km (103.8 mi) long, making it the10th longest river in the Czech Republic.
The first written mention of Jizera (asGizera) is from the 13th century. The origin of the name is most likely Celtic and is derived from the verbal root-eis, -ois, -is, meaning "to flow briskly". It has the same etymology as theIsar in Germany, the Yser/IJzer in Belgium and France, theIsère in France and probably theAire in England.[1]
The Jizera originates in theJizera Mountains. Two sources of the river are defined. The first spring (so-called "Czech spring of the Jizera") is located on the slopes of Mt.Smrk in the territory ofLázně Libverda on the Czech side of the border at the elevation of 984 m (3,228 ft) and for centuries it was considered the only source of the Jizera. In the 1990s, the so-called "Polish spring of the Jizera" was determined (on the slopes of Mt. Stóg Izerski in the territory ofGmina Mirsk on the Polish side at the elevation of 1,035 m (3,396 ft)), as the source of aheadwater that is longer and more substantial than the Czech one, but historically it was a separate stream with a different name.[2][3]
The Jizera flows toLázně Toušeň, where it enters the Elbe River at the elevation of 169 m (554 ft). Considering the "Czech spring of the Jizera", it is 167.0 km (103.8 mi) long, making it the10th longest river in the Czech Republic. Considering the "Polish spring of the Jizera", it is 167.5 km (104.1 mi) long, of which 1.4 km (0.9 mi) is in Poland. The Czech-Polish border is formed by 17 km (11 mi) of the river. Itsdrainage basin has an area of 2,193.4 km2 (846.9 sq mi), of which 2,145.2 km2 (828.3 sq mi) is in the Czech Republic.[4][5]
The longest tributaries of the Jizera are:[6]
| Tributary | Length (km) | River km | Side |
|---|---|---|---|
| Mohelka | 41.6 | 61.4 | right |
| Kamenice | 36.9 | 101.0 | right |
| Oleška | 36.0 | 106.3 | left |
| Klenice | 29.3 | 36.9 | left |
| Žehrovka | 26.3 | 66.9 | left |
| Zábrdka | 24.5 | 55.2 | right |
| Jizerka | 21.5 | 121.7 | left |
| Libuňka | 21.4 | 78.4 | left |
| Strenický potok | 20.3 | 30.6 | right |
| Bělá | 15.0 | 49.1 | right |
A notable tributary is also theMumlava River, which has an average discharge near estuary at 1.98 m3/s (70 cu ft/s).
The largest settlement on the river is the city ofMladá Boleslav. The river flows pastKořenov,Rokytnice nad Jizerou,Jablonec nad Jizerou,Semily,Železný Brod,Malá Skála,Turnov,Mnichovo Hradiště,Bakov nad Jizerou, Mladá Boleslav,Benátky nad Jizerou,Předměřice nad Labem,Tuřice,Nový Vestec,Káraný andLázně Toušeň.
There are no reservoirs or fishponds built directly on the Jizera. The largest body of water in the basin area is the Josefův Důl Reservoir with an area of 131 ha (320 acres), built on theKamenice. There are 1,350 bodies of water in the basin area.[4]
There are many species of molluscs in the river. Among the most endangered species areCochlodina dubiosa corcontica,Daudebardia brevipes,Planorbis carinatus,Clausilia cruciata,Euconulus praticola,Pseudotrichia rubiginosa,Ruthenica filograna,Semilimax kotulae,Vertigo alpestris,Vertigo antivertigo andVitrea subrimata.[7]
Jizera is one of the cleanest rivers in the country and there is a high density of fish, which is why it is popular for fishing. The upper and middle courses are mainly inhabited bybrown trout andgrayling.[8]
Jizera is a resource ofdrinking water for the city ofPrague and the central part of the Central Bohemian Region. It supplies Prague with drinking water from approximately one third of the total need, the rest of Prague's need is covered by water from theŠvihov Reservoir. FromBenátky nad Jizerou to its on-flow, the Jizera is surrounded by bank infiltration system, and in the municipality ofSojovice the water is being pumped for artificial infiltration.[9]
The Jizera is suitable forriver tourism. Due to its mountainous character, the upper course is popular among experienced paddlers, but within the entire river there are sections of all difficulties.[8]
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