Mitterwasser

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Mitterwasser
Data
Water code AT : HZB: 2-126
location South of Linz , Upper Austria
Drain over Ipfbach  → Danube  → Black Sea
River basin district Danube below Jochenstein (DUJ)
origin Outflow of the Weikerlsee near Posch
48 ° 15 ′ 52 ″  N , 14 ° 22 ′ 27 ″  E
Source height 245  m above sea level A.
muzzle at Kronau coordinates: 48 ° 14 '10 "  N , 14 ° 25' 51"  E 48 ° 14 '10 "  N , 14 ° 25' 51"  E
Mouth height 243  m above sea level A.
Height difference 2 m

length approx. 6 km 
Right tributaries Aumühlbach , Aubach (indirect), Ipfbach
Communities Linz , Asten , Luftenberg on the Danube , Enns .
Oxbow river of the Danube (also confluence directly with it); NSG and Natura 2000 Traun-Donau-Auen

The Mitter water is an oxbow lake of the Danube in Linz in Upper Austria .

Course and Hydrography

The Mitterwasser is a former right branch of the Danube in the Linzer Feld near Ebelsberg and Enns , which was previously navigable. It was cut off from the watercourse by the Traun and Danube regulations and is partially silted up.

Today the Mitterwasser rises as an overflow from the Großer Weikerlsee , a quarry pond from the 1940s directly at the mouth of the Traun near SolarCity , in the Posch cadastral area . It then absorbs the overwater of the Weikersee retention basin, which lies between the large and small Weikerlsee , and the Aumühlbach from Ebelsberg. Then it runs along the edge of the Donauauen to the Ausee , which it does however. The old Ipfbach flows here, which leads from Asten via Raffelstetten . Then the middle water divides into a southern and a northern branch; to the latter there is another side channel. The southern branch flows together with the (new) Ipfbach, shortly afterwards the northern branches flow in again. The Mitterwasser (or the Ipfbach) flows into the Danube already north of Lorch , near Kronau .

The Mitterwasser is about 6 kilometers long to the Ipfbach, and another 2 km to the confluence with the Danube. The width of the oxbow lake is now in the range of 10 to a maximum of 70 m, the depth is a little over 1 m, the gradient over an 8 km run is only 5 meters in altitude.

Due to the regulation and embankment of the Danube, all of the Traun-Danube floodplains belong to the catchment area of ​​the Mitterwasser. From the Weikerlseen to the Raffelstetten level, the Mitterwasser is on the right bank (south) accompanied by a flood protection dam.

history

In the past, the Mitterwasser was not the southernmost tributary of the Danube; in the 18th century there was an older tributary that ran directly in front of Raffelstetten , Ipfdorf and near Fisching, which is now deserted Astener Ort (sewage treatment plant). This arm was probably even earlier as part of the port estuary of the River Traun via the middle Aumühlbach and Altau directly from Ebelsberg. In the early Middle Ages the important land was in Raffelstetten , where the barges, which came down the Traun with the Salzkammergut salt , were reloaded for onward transport on the Danube or for transfer to the northern bank of the Danube (see Raffelstetten Customs Regulations , around 900).

Because of the border of the Mühlviertel which used to run in the middle of the river, the areas on the left bank belong partly to the Perg district (municipality of Luftenberg ).

ecology

The Mitterwasser is an ecologically valuable eye water. Its banks are heavily reeded in places, otherwise bordered by alluvial forest , sometimes fields extend right up to the bank. The river bed is gravelly to muddy, depending on the local current.

The eye water is the habitat of numerous native water bird species ( coots , swans , mallards , gray herons , tufted ducks, great crested and little grebes , kingfisher ) and dragonflies (quadruped, mosaic and azure damsel, king-bellied, flat-bellied, pitch and darter). Sometimes there are extensive blankets of the yellow pond rose . Special features are also a water hose and water spring . The elongated shallow water pool that accompanies the flood dam on the outside is an important amphibian biotope, with tree frogs, jumping frogs, water frogs, pond and sea frogs, common toads and yellow-bellied toads.

The Mitterwasser forms the core area in the eastern part of the Nature Conservation and European Protection Area (FFH) Traun-Donau-Auen , which only extends as far as the Linz city limits. The remaining parts of the middle water are not under special protection, apart from the basic water protection (50 m zone).

The Linz-Asten sewage treatment plant is located where Fisching used to be, and its outlet then goes to the Mitterwasser.

Individual evidence

  1. ↑ a b c d e f According to the water book , only the upper course is listed as Mitterwasser: GGN 429621 Mitterwasser (only outside the Linz city limits); 951 Mitterwasser from the confluence of the theoretical water path of the Aubach at Ausee and for the southern part of the Mitterwasser (together with the Aubach), 429648 Mitterwasser feeder and 429649 Mitterwasser feeder for the two northern sections, and 953 Ipfbach from the Ipfbach mouth: no continuous stationing; the HZB (area directory) , on the other hand, gives Mitterwasser for the entire course, so that the Mitterwasser flows into the Danube (code 2-126 in this regard), and the Ipfbach and the Aubach are tributaries (information according to DORIS: Layer waters , stationing 1000 km and detailed catchment areas , Status 2018).
  2. ↑ a b c d The Josephinische Landesaufnahme (around 1780) shows the bank of the Danube mainstream in the area from the Weikerlsee, in the area of ​​the Ausee floodplain, which extends to the local border of Raffelstetten (today's mouth of the Tagerbach ), and today The water ends at Kronau ; the Raffelstettener arm is still fully developed in the Franziszäische Landesaufnahme (around 1830) the course of the Mitterwasser is already visible to the north parallel to the Raffelstettener arm; In the Franzisco-Josephinische Landesaufnahme (around 1870), after the first constructions, the current course is recorded as an active branch (all regional recordings online at Arcanum / Austrian State Archives: mapire.eu ).
  3. ↑ a b c d e f Friedrich Schwarz: Alluvial forest on the outskirts - a hike through the Schwaigau. 9th part of: Natural history hiking guide through the city of Linz. In: City of Linz, Naturkundliche Station (Ed.): ÖKO · L - Journal for Ecology, Nature and Environmental Protection 26/2 (2004), keyword Mitterwasser , p. 3, column 2 ff, photos Fig. 2, 3 and 6, p. 4 f, whole article p. 3–10, PDF on ZOBODAT there p. 1 ff.
  4. ↑ a b c d Erich Kainz, Reinold Janisch; Federal Agency for Fisheries Management in Scharfling / Mondsee (Ed.): On the fish population in the waters in the south and south-east of Linz. In: Naturk. Jb. D. City of Linz 33, 1987, 2.4. Mitterwasser , p. 244 and results 4.4., P. 260, whole article p. 233–270, PDF on ZOBODAT there p. 12 resp. 28.