Isel
The Isel is a river in the Austrian East Tyrol and a tributary of the Drau . It rises from the Umbalkees at an altitude of 2,400 meters and flows eastward as the Kleine Isel through the Umbaltal and then to Matrei its continuation called Virgental . There it takes up the roughly equally powerful Tauernbach as a left tributary and flows as the Große Isel in what is now called the Iseltal valley in a south-easterly direction to the mouth of the Drau near Lienz, which is 670 meters above sea level . The Isel has a total length of 57.26 kilometers and a gradient of 1730 meters. It drains a catchment area of 1,200.86 km², in which there are a total of 48 named rivers . The Tauernbach is followed by the Schwarzach and the Kalserbach as further major tributaries .
geography
geology
The Isel flows through uniform formations of crystalline slate along its entire length . Only in the lower part of the Virgen Valley from Virgen to Matrei does it flow through very heterogeneous layers of metamorphic limestone and dolomite rocks . To the south of Matrei, however, gravel and sand determine the structure of the valley floor. Between Huben and Lienz , the Isel flows through a flat, relatively wide trough valley , until it is pushed to the right side of the valley by the Oberlienzer alluvial cone before Lienz and has partly rocky banks.
course
The Isel rises at the head of the Umbaltal valley in a glacier gate of the Umbal Lake, which, with a surface area of around 5 km², forms the main glacier of the Umbal valley in the Venediger group of the Hohe Tauern . After the glacier gate , the river forms a small lake and then flows a few kilometers in a south-easterly direction through the Umbaltal, which is sharply cut as a Kerbtal . Leading to the east, the Isel then overcomes several gradients with small-scale leveling, of which the multi-level Umbal Falls ("Isel Cataracts") are a well-known and highly frequented tourist destination in the Hohe Tauern . Then the Isel flows through the Virgental , which runs from west to east into the Matrei basin. Starting from Ströden , the Isel now takes a curved course, which is determined by the deepened brook bed and gravel cone (forced meander). The river overcomes another steep step at the hamlet of Bobojach in the Isel Gorge, as a result of which the Isel is pushed to the right side of the valley by the Virgen alluvial cone. After a short downward gradient, the Isel finally reaches the Matrei Basin, where the Tauernbach flows from the north . Up to this point the river has surmounted over 1400 m.
Now running to the southeast, the Isel reaches the village of Huben after a valley step overcome in cascades . After that, the course of the Isel is again characterized by alluvial cones and barriers. In the so-called lower Iseltal , the river passes the communities of St. Johann im Walde , Ainet and Oberlienz. In the urban area of Lienz , the river flows into the Drava with an average water flow of 38.8 m³ / s, which at this point only carries 14.2 m³ / s water.
history
etymology
According to the most common interpretation, the name Isel goes back to the Celtic word ys (fast, tearing). According to another interpretation, however, ys stands for high and low at the same time and thus designates the vertical. A more recent interpretation refers to a hypothetical Indo-European root es or is and derives a generic term for "(flowing) water" from it. In addition to the Isel, more than 200 water body names all over Europe can be traced back to this word stem, other examples are the Issel / IJssel (Netherlands), the Isar ( Germany ) or the Iser ( Czech Republic ).
Settlement history
The Virgental, through which the Isel flows, and the Iseltal belonged to the most important settlement areas in East Tyrol. In addition to the main settlement area Lienz ( Aguntum ), a settlement focus also developed in today's municipality of Virgen on the upper reaches of the Isel. Ceramic finds prove the permanent presence of people here as early as the Neolithic . After that, the upper Isel valley, with a focus on Virgen, developed into the main supplier of ores in the Bronze Age . A grave field excavated near Welzelach from the later Hallstatt period proves the importance of the Virgen area in later times. While the settlements in today's area of Lienz were still on hills, the ancient city of Aguntum was built at the beginning of Roman times on the valley floor of the Lienz basin, which was flooded by the Isel and Drau . The Romans took advantage of the favorable geographical location at the intersection of the Drautal-Straße and the road through the Iseltal. After the fall of the Roman Empire, the Slavs settled in the Isel valley, but from the 8th century they were increasingly displaced by the Bavarian colonists.
environment
fauna and Flora
The upper course (Umbaltal) of the Isel is largely characterized by dwarf shrub heaths and alpine lawn communities up to a height of about 2,100 meters . This often includes areas used for alpine farming . In the Virgental, below the permanent settlement area, almost exclusively the orographic left bank is used for agriculture. The right bank and the area above the permanent settlement area, however, are dominated by coniferous forests . Since the Matrei Basin below the Virgental is used intensively for agriculture, the original alluvial forests in this area have disappeared. On the lower reaches of the Isel between Huben and Lienz, there are again various stages of floodplain succession , especially on the wide gravel areas of the gravel basin .
There are no artificial obstacles for migrating fish in the entire course of the Isel. Natural obstacles are the valley entrance into the Virgental, the gorge stretch in front of Prägraten (Isel Gorge) or the Umbal Falls. Although the upper reaches of the Umbaltal no longer have any major obstacles, fish stocks are very unlikely here. In the upper reaches to Matrei, rainbow trout live in the Isel , in the lower reaches there are trout, grayling and huchen .
natural reserve
The upper reaches of the Isel lie partly in the Hohe Tauern National Park , with the Umbal Falls in the rear Virgental and the upper reaches of the Isel from the Daberbach estuary in the outer zone of the National Park. The uppermost part of the Umbal Valley is ultimately in the core zone of the national park. Below Huben, the Isel flows through several water protection zones. Often the Austrian Environment Association , the Alpine Association and the Forest Board of Trustees have called for the Isel to be included in the Natura 2000 protection program, most recently in August 2011. This step is justified in particular with the occurrence of the German tamarisk, which is worth protecting . Since the state of Tyrol had not yet responded to such demands, environmentalists urged the EU to send a warning letter to the state of Tyrol. It has been known since January 2013 that the EU Commission is calling for the Isel and its tributaries to be protected and has initiated an informal preliminary procedure.
From the point of view of nature conservation, the Isel is a very rare type of flowing water area due to its catchment area, which is unique in East Tyrol. The State of Tyrol attested 80% of the Isel course to be of high to very high nature conservation value. Only the sections within larger settlements are classified lower.
On June 30, 2015 the Tyrolean state government decided to nominate the course of the Isel from the Umbal Falls to the city limits of Lienz, the upper reaches of the Schwarzach and the Kalser Bach as Natura 2000 area.
Bank condition and building measures
The course of the Isel is accompanied over long stretches by longitudinal structures (block protection) and transverse structures ( groynes ). This does not apply to the upper reaches with the Umballfalls. From Ströden (Hinterbichl) the banks are blocked by block stone protection. Natural stretches can then be found especially within the Isel Gorge and below the Virgen gravel cone up to the valley entrance at the Matrei basin. Block protection is also decisive for the course of the Isel between Matrei and Huben. Between Matrei and Lienz there are also sections with a generously widened sole. The right bank in particular has remained undeveloped here and is partially lined with alluvial forests. The left bank is largely secured by block stones, and an asphalt dam path (bike path) accompanies the Isel. The course of the Isel in the urban area of Lienz is particularly hard-built to the right by embankment masonry that narrow the Isel like a canal. The left bank is largely secured by blocks and groynes.
Water quality
The Isel has excellent water quality in the upper reaches of Virgen. Only when dirty water is discharged in the Virgen area does the water quality class fall to level II. Between Matrei and Huben, the Isel again achieves the highest water quality. Due to seasonal fluctuations in tourism and the associated partial overloading of the sewage treatment plant, the quality class in the following river area deteriorates to II to III. In the mouth area, the river finally regains biological quality class I. Since a new local canal is currently being built for the Hinterbichl, Prägraten and Virgen area, an improvement in the water quality in the upper reaches is in prospect.
Economic and tourist use
The Isel is currently not used for energy purposes, there is only a power plant at the confluence of the Kalserbach , which only affects the Kalserbach. In the 20th century, however, there were plans to use a number of tributaries of the Isel on a large scale for energy purposes - see: History of Kals am Großglockner . The further use of the river or its tributaries for energy purposes is currently politically controversial. Although the planning of the Matrei-Raneburg pumped storage power plant, which also suggested the use of the Isel, and a power plant on the lower Isel were canceled, there have been plans since 2011 to financially rehabilitate the neighboring communities with a diversion power plant on the upper Isel ( Virgental ) to build. In contrast, a citizens' initiative has formed.
On June 14, 2012, there was a vote in Prägraten and Virgen on the “construction and planning of an environmentally friendly power plant on the Isel”, which was mostly for the power plant, but was controversial from several sides. In Matrei , the municipality is currently considering a diversion power plant from a private investor due to financial needs.
The Isel is a popular starting point for water sports such as canoeing , white water paddling and rafting over long stretches . In addition, the river is used by anglers in many places due to its abundance of fish. The 29 km long Isel cycle path connects Matrei with Lienz. The natural stone factory Lauster organized a stone carving symposium in the 1990s, the works of which were displayed on the Isel.
various
- In Vienna-Floridsdorf , Iselgasse has been named after the river since 1953 .
Web links
Individual evidence
- ↑ Hydrographisches Jahrbuch Österreichs 2008, S. OG322
- ↑ Mean values of the Lienz-Peggetz Drau level 1 km below the mouth of the Isel minus the mean values of the Lienz Isel level
- ↑ Natura 2000: Whole Isel nominated , ORF.at, June 30, 2015.
- ↑ Secret: Prägraten and Virgen are planning the Isel power plant
- ↑ Citizens' initiative against the Virgental power plant
- ↑ Results of the survey on the planning of a power plant on the Isel
- ↑ Statement of the citizens' initiative against the Virgental power plant (PDF file; 218 kB)
- ↑ Kleine Zeitung: The power of the Isel beckons
