Grosse Aa (Sempachersee)

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Grosse Aa
Fuchsweidbach, Sellenbodenbach, Neubaubach
Data
Water code CH : 767
location Mittelland

Switzerland

River system Rhine
Drain over Suhre  → Aare  → Rhine  → North Sea
source at Huobschür
47 ° 4 '39 "  N , 8 ° 11' 24"  O
Source height 723  m above sea level M.
muzzle Sempachersee coordinates: 47 ° 7 ′ 31 "  N , 8 ° 11 ′ 15"  E ; CH1903:  656 826  /  219 648 47 ° 7 '31 "  N , 8 ° 11' 15"  O
Mouth height 504  m above sea level M.
Height difference 219 m
Bottom slope 23 ‰
length 9.6 km
Catchment area 15.7 km²
Discharge at the Sempach
A Eo gauge : 15.7 km² 		NNQ (1998)
MQ 1985–2017
Mq 1985–2017
 HHQ (2005) 		0 l / s
306 l / s
19.5 l / (s km²)
 32.4 m³ / s
Left tributaries Voramstegbach
Right tributaries Waldbach
Communities Ruswil , Neuenkirch , Sempach

The Grosse Aa , according to the Federal Office of Topography Gross Aa , is the main tributary of Lake Sempach, around 10 kilometers long, in the Swiss canton of Lucerne . In the upper reaches it bears the names Fuchsweidbach, Sellebodebach (Sellenbodenbach) and Neubaubach one after the other.

geography

course

The Grosse Aa rises at 723  m above sea level. M. in a hillside forest on the eastern slope of the Homberg ( 839  m above sea level ) directly at the listed Huobschür . Little south-southeast rises at the spring horizon of Kellenbach , but what about the Light Buhler Rotbach in the Reuss drained.

It initially runs to the east through the forest, followed by a section with dense bank wood near Bodematt , in which the stream turns north. It reaches the Steimattwald and forms a small ravine , where they before in Neuenkirch continues to flow, short marks the municipal boundary. After a curve to the southeast, it reaches Neurütistrasse , where the ravine was filled up for the route. After crossing under the road, it turns to the east and now forms a ravine cut deep into the clay till of the moraine. In the process, the Grosse Aa came across the Upper Sea Molasse, which is mainly composed of sandstones . Here it flows through waterfalls up to 15 meters high, while the slopes are marked by landslides.

It reaches Hof Bremgarten and at the same time takes up the Bodenmattbach from the right, before continuing to flow shortly to the northeast, passing Hof Gspan . At the confluence of the Steinmattbach from the left, it bends to the east and continues to flow in its direction of flow. The brook is now lined with thick wood with occasional tall trees. The Grosse Aa crosses under Neuenkirchstrasse and reaches the mouth of a right tributary, which is shaped by a narrow forest, and continues its direction of flow to the northeast. It passes the Stritholz farm on the right , while the Lonwald runs along the other bank at a short distance . From here, several drumlins and round humps rise along the course of the stream up to the mouth .

A small pond below the Bernhof follows on the right bank , before flowing between the slightly elevated Lohn farm in the west and the Bärnhof forest in the east. After a small wetland area with three ponds on the left bank at Hof Emmenwald , it is bridged by the Weiherhüsli Bridge, built in 1838 , a stone arch bridge over which Hauptstrasse 3 now runs. In the hamlet of Rippertschwand that follows shortly afterwards, the Grosse Aa turns in an arc to the northwest. Here it forms the western village boundary and then flows at the court Kenelmatt over before the right bank of Scheibenstand follows the shooter's house Neuenkirch, being shot over the creek.

After the confluence of the Voramstegbach from the left, it passes the Neuenkirch, located a little to the west on a hill, and flows through the hamlet of Sellenboden . It follows the confluence of the village stream from the left, before it turns again to the northeast at Maiengrüeni , and is still accompanied by a wood border. After crossing under the Olten – Lucerne railway line , it reaches the hamlet of Adelwil , where the forest stream flows into it from the right . At the same time, it bends to the northwest and forms the development boundary of the Sempach Station district, while the Fenerehubel ( 562  m above sea level ) rises on the right bank . From Gottsmänigen , the Kleine Aa flows parallel to it a little further north .

It now marks the municipal boundary to Sempach for around 150 meters before it crosses the border completely and touches the Seesatz on the right bank . Here it is bridged by Hauptstrasse 296 ( Luzernerstrasse ) and Schlichtistrasse . The bridge of the Seelandstrasse follows before it flows through a campsite. Here the stream is spanned by a covered wooden bridge, the only remaining one in the community. Finally, the Grosse Aa flows into the middle of the campsite at 504  m above sea level. M. in the Sempachersee.

Catchment area

The catchment area of ​​the Grosse Aa measures 15.7 km², of which 71.8% is agricultural area, 18% wooded area , 10% settlement area and 0.2% water area.

The highest point of the catchment area is 839  m above sea level. M. at the practice area near Gross Homberg (Ruswil), the average altitude is 589  m above sea level. M. The average annual rainfall is at the upper course at 1266.72 mm, at the underflow from Adelwil he is 1148.41 mm

See also

Individual evidence

  1. ↑ a b c Geoserver of the Swiss Federal Administration ( information )
  2. ↑ a b Topographical catchment areas of Swiss waters: sub-catchment areas 2 km². Retrieved July 20, 2018 .
  3. ↑ Grosse Aa - Sempach. (PDF) In: Environment and Energy Canton Lucerne. Retrieved July 21, 2018 .
  4. ↑ Herischwandwald. (PDF) In: Inventory of the natural history of significant forest objects in the Canton of Lucerne. Retrieved July 21, 2018 .
  5. ↑ Topographical catchment areas of Swiss waters: area outlets. Retrieved July 20, 2018 .
  6. ↑ Base areas (catchment areas) HADES. Retrieved July 20, 2018 .
  7. ↑ Base areas (catchment areas) HADES. Retrieved July 20, 2018 .