Schwemmbach
The Schwemmbach , also called Riedlbach , older Ach-Bach or Triftbach and still called Scheiterbach today , rises in the southeastern Kobernaußerwald in Upper Austria and flows into the Mattig .
Hydrological description
Run and landscape
Its source is in the municipality of Lohnsburg am Kobernaußerwald , on the Steiglberg at 700 m above sea level, in the area of the Talungsmulde on the main ridge of the Hausruck and Kobernaußerwald train between Steiglberg and Hamberg to the east.
He is from the turn of the Schwarzmoos valley near the village Hocheck (municipality Pöndorf) as Schwemmbach named and is above this point, still with the locals Riedl Bach ( FLOZ 3). In the water index of the hydrographic service, however, the uppermost section is also referred to as Schwemmbach . From the confluence of the Schwarzmoosbach, the Schwemmbach has FLOZ 4. In this section, two side valleys branch off to the right , Hundstal (to Hamberg) and Rabenbachtal (to Schranne ). In the Schwarzmoostal left the L508 Kobernaußer Straße runs to Steiglberg and the Innviertel .
The Schwemmbach flows in a south-westerly direction via Höcken (municipality of Lengau) and Schneegattern between the southern edge of the Kobernaußerwald and Krenwald . The expansion of the L508 on the Kobernaußerwald side ends at Höcken, the L1282 Pöndorfer Straße leads into the Vöcklatal . At Schnegattern the Weißenbachtal flows , at Ober- and Mittererb Erknertal and Mehrental (from the Stierberg ), each from the north (right),
At Friedburg the Schwemmbach enters the wide Mattig Valley , where it turns northwest and takes up the Hainbach (from Straßwalchen). Via Teichstätt and Munderfing, it follows the foot of the Kobernaußerwald in a straight line with a few small channels. Several small valleys branch off, Rossmarktal near Heiligenstatt , Bräutal near Aug , Parzer Valley near Parz , Achtal near Achtal , Katztal near Katztal and Teufeltal near Munderfing- Bradirn . This further run is followed by the B147 Braunauer Straße and a little further away the Mattigtalbahn .
Then it flows towards Mattighofen towards the middle of the valley , but passes the town through a hook to the east between town and Schalchen . It continues largely in a straight line to the other side of the valley, where the Schalchener Brunnbach joins. Then it flows into the Mattig from the right at Höfen (municipality of Helpfau-Uttendorf) south of Uttendorf.
Up to its confluence at about 420 m above sea level. A. It has a total length of 35.7 km and drains a catchment area of around 220 km².
The Schwemmbach covers an altitude difference of approx. 250 meters in its longitudinal course, the gradient is relatively constant over its entire length and averages 6.6 ‰. Only the top 5 km show a significantly higher gradient of 15 ‰. According to the basic types of running water in Austria, it belongs to the waters of the northern foreland .
Catchment area and tributaries
Through its course, the Schwemmbach drains the entire south and west side of the Kobernaußerwald, the upper Mattig valley as well as the Straßwalchen municipal area between the Wallerseegebiet and Vöcklatal to the municipality of Oberhofen , which is already part of the Mondseeland and the Salzkammergut , and thus also the north side of the Irrsberg , the last foothills of the Alps ( Salzkammergut Mountains ).
More important feeders are:
- Hundstalbach left, with 2.8 30 km² catchment area
- Rabenbach left, with 2.9 30 km² catchment area
- Schwarzmoosbach right, with 2.9 30 km² catchment area
- Weißenbach , which flows into the right at Schneegattern (km 23.9), drains a catchment area of approx. 30 km²
- Hainbach bei Teichstätt, drains a catchment area of 62.4 km² around Straßwalchen
- Schalchener Brunnbach , just above the mouth of the Schwemmbach from the right, with a catchment area of also approx. 30 km².
Drain
At the Schwemmbach, the discharge conditions are documented by three writing levels of the Hydrographic Service. At the lowest level near Furth (river km 2.0) the mean annual low water (MNQ) of the series 1981–1989 is 0.15 m³ / s, the mean discharge (MQ) 0.87 m³ / s and the mean high water ( MHQ) 6.6 m³ / s. In relation to the catchment area, the mean water discharge at the Furth gauge corresponds to a water discharge of only 4.6 l / s.km². This small amount of water is not to be seen as a result of lower amounts of precipitation, but rather as a result of the seepage into the subsoil.
According to the information provided by the Hydrographic Central Office, the flow regime at Schwemmbach shows only slight fluctuations compared to other rivers in Upper Austria: In the winter months from December to April, the flow rates are around or just over 1 m³ / s, in the months of September and October around 0, 5 m³ / s.
History and geology of the alluvial stream
Geologically, the catchment area of the Schwemmbach belongs to the southern part of the Alpine foothills . Geologists refer to this area as the Molasse Zone . In these tertiary sediments, several layers of gravel and sand containing natural gas and crude oil are stored in the catchment area of the alluvial stream.
The Kobernaußer Wald is the remnant of a huge alluvial fan that was deposited ten to two million years ago in the Molasse basin by the rivers coming from the young Alps and later solidified. It can be assumed that the entire Innviertel was originally covered by a coherent blanket of Hausruck and Kobernaußerwald gravel, but that this was eroded to varying degrees over large parts by a later land uplift and the resulting greater erosion and the subsequent development of new drainage systems. In the southern part of the Siedlberg and in parts of the Geinberg, remnants of this gravel are still preserved. In the Schwemmbach valley and the parts of the Innviertel further to the west, this late-Tertiary gravel was removed down to the depths and is now covered by fluvio-glacial Pleistocene sediments. In the Kobernaußerwald the coal-bearing freshwater layers are still the main mass.
Ice Age consequences
Called the Ice Age period , it began about two million years ago and shaped the western part of the Schwemmbach valley. Of the four ice ages, only traces of the two younger ones , the Riss and Würme ice ages, can be found in the Schwemmbachtal . The Salzachtal Glacier, coming from the Alps and creating the Salzburg Lake District , pushed forward to the terminal moraines at Palting and Kerschham , the Mattig Valley was probably a typical glacial foreland, swampy and perhaps with a glacier end lake . Towards the end of the respective ice age, the glacier ice melted, huge amounts of water could now transport the material transported by the glacier far north and deeply excavate a wide valley between the Kobernaußerwald and the plateau of the Südinnviertel lake area . When the meltwater became less, sedimentation set in instead of erosion and large, flat terrace areas were accumulated. The younger meltwater streams eroded and accumulated again in the existing, older terrace corridors. The older and higher high terrace comes from the Riss period , the younger, deeper low terrace from the Würm Ice Age . A narrow, somewhat deeper alluvial plain, the floodplain of the Schwemmbach, has sunk into this since the end of the Ice Age.
Economic use, regulation and flood protection
From the Salbuch of the Friedburg rule from 1363 it emerges that the fishing rights on the Schwemmbach belonged to this rule. Later the right passed to private owners through purchase. In terms of fishing , the Schwemmbach was and is still considered good trout water , as a report from around 1930 in the Luxembourg hunting newspaper Chasse et Peche shows.
The Schwemmbach was rebuilt as early as 1765 for the purpose of the Holztrift , which at that time gave the brook an acceptable straightening and relocation. The construction of the Trift facility was started by the Chur Bavarian government. It consisted of the four Triftklausen (= water reservoir) located north and northeast of Schneegattern, namely the Riedlbach- , the Rabenbach- , the Achbach- and the Weißenbachklause . After the Innviertel came to Austria in 1779, the expansion work was continued and completed. In 1882 the Schwarzmoosklause was added. The drift channel was made wide throughout in order to achieve a constant water depth during the drift. For this reason, between the northern exit of Munderfing and the mouth at Höfen, the Schwemmbach was laid along the Reichsstraße, with the artificial channel in the Mattighofen area being directed to the eastern border of the town. The original Schwemmbach is the Mitterbach , which flowed through Schalchen.
The management of the drift system, the supervision of the Klausen and rakes, the preparation and supply of the firewood as well as the management of the clearing were the responsibility of the Triftamt in Weißenbach near Schneegattern, established in 1812 . Only later, under Austrian rule, was the management of the company to the k. u. k. Transferred to the Forestry Office in Friedburg. The Trift stretch to Hagenau was a total of 52 kilometers, with the Schwemmbach 28.7 kilometers and the Riedlbach and Weißenbach each 6 km, the rest allotted to the Mattig. From 1820 to 1861 an average of 7,601 fathoms (240 logs each) (a total of around 52,000 m³ annually) were drifted in soft and hard wood. The highest amount of drift was found in 1835 with 10,795.5 fathoms of wood.
In the municipality of Munderfing alone, the Schwemmbach drives three sawmills and three small power plants with its hydropower. The weir systems required for this prevent the passage to this day, as no fish migration aids have been installed. Likewise, no fish pass has been created for the publicly built retention basin in Teichstätt.
At the turn of the century, the first flood protection measures were taken in the local area of Munderfing , but these were only carried out on a small scale.
The Hainbach is a small, but very flood-prone stream. Formerly it had no estuary and seeped away in the Lengau village of Bach at the latest , but led more and more water through sealing and drainage and in 1964 it penetrated for the first time via Valentinhaft to Munderfing. In 1968 it was moved to a new creek bed, called the Mittelwasserüberführung , and later discharged into the Schwemmbach below the current retention basin.
In the years 1969 to 1971, the regulations in the Achenlohe area and the regulations south of Munderfing in the years 1972 to 1976. With the last two regulations outside the local area, in the hardly built-up area, a straightening with bank and bed protection (hard version with blocks).
Two flood retention basins were later built in the municipality of Lengau . These two basins hold so much water that they can cope with 50-year floods at the current level of expansion. Since these flood retention basins limit the outflow into the Schwemmbach to 6 m³, the flood risk on the Schwemmbach has now been largely eliminated.
literature
- Room unit Mattigtal . In: Office of Upper Austria. Provincial government, nature conservation department (ed.): Nature and landscape - models for Upper Austria . tape September 26 , 2007 ( PDF [accessed October 5, 2011]).
- Office of the Upper Austrian Provincial Government: Mattig and Schwemmbach, investigations into water quality. Status 1992–1994, series subdivision water protection (ed.): Water protection report 10/1995, Linz 1995.
- Norbert Berner: Fish ecological studies on the Schwemmbach near Munderfing. Project work, 2007.
- Munderfing community (ed.): Munderfing am Kobernaußerwald, Das neue Heimatbuch , Ried im Innkreis 2005, various Ss.
Individual evidence
- ↑ Detailed water bodies : Riedlbach to the confluence with Hundstalbach (DWK: 302670000, km 32), Riedlbach / Schwemmbach to km 27 (near Höcken, DWK: 305720004), Schwemmbach to the mouth (DWK: 305720005)
- ↑ a b c d e f DORIS, Layer Water & Geology
- ↑ Federal Ministry for Agriculture, Forestry, Environment and Water Management (ed.): Hydrographisches Jahrbuch von Österreich 2009. 117th volume. Vienna 2011, p. OG 146, PDF (12.1 MB) on bmlrt.gv.at (yearbook 2009)
- ↑ an old room measure for firewood, 1 fathom corresponds to 6.8224 m³ in Austria