The Wüeribach (also called the Dorfbach and Fischbach in its upper reaches) is a tributary of the Reppisch , around 8 kilometres long, in the Canton of Zürich in Switzerland . It rises in the municipality of Bonstetten , flows through the narrow Wüerital valley and reaches the Reppisch valley near Birmensdorf , wo it empties, parallel to the rather smaller Lunnerenbach , into the lower Reppisch. The Wüeribach is the longest and biggest tributary of the Reppisch and has an average flow rate of 310 L/s.
8-466: The Wüeribach rises as the Dorfbach at 643 m above the sea in the forest area of Birch above Bonstetten. From here it flows initially mainly in a northwestern direction through the village of Bonstetten, much of it being canalized as it passes through. It leaves the village and runs, having been straightened out, through fields across a wide plain in a northern direction. Shortly afterwards
16-686: A meltwater gully of the Wettswiler and the Aescher Zunge of the Reuss Glacier . The Wüeribach now reaches Birmensdorf, collects the Aescherbach from the left and finally discharges into the Reppisch at an elevation of 461 m above the sea . The catchment area is 14.6 km and extends over the districts of Affoltern and Dietikon . 51.6% of the catchment area is used for agriculture, 24.6%
24-583: A new orthometric height vertical reference point, fixed to the geoid . The height of the new reference point, Zimmerwald Observatory , was chosen so that the Pierres du Niton reference point maintained its then current level. The heights of LHN95 differ from the LN02 heights by up to 50 cm (20 in). Due to the danger of confusion caused by the change in the height systems, new heights for official measurement have nevertheless not been introduced. Establishment of
32-597: Is built up and 23.9% is near-natural vegetation and forest. The highest point of the catchment area is 680 m above the sea in Islisberg , its average elevation is 572 m above the sea In the south is the catchment of the Hofibach, which drains into the Jonen ; in the west is the catchment of the Aescherbach and to the east and north lies the valley of the Reppisch. First- and higher-order tributaries of
40-676: The Siegfried Map and the Dufour Map , both of them widely used) is 3.26 m higher than today's official values. At the border between Switzerland and Austria , the Swiss heights are 6 to 75 mm higher than the Austrian heights above the Adriatic . As gravitational potential cannot be neglected for applications with high accuracy requirements, the Swiss national height network 1995 (LHN95) created
48-660: The Wüeribach with their length: Meter %C3%BCber Meer Metres above the Sea ( German : Meter über Meer (m ü. M.) ) is the vertical datum used in Switzerland . Both the system and the term are also used in the Principality of Liechtenstein . In Switzerland, levelled heights from the Swiss national levelling network 1902 (LN 02) are used as official heights without compensation for gravity . The reference point for
56-719: The Swiss national height network is the Pierres du Niton ( French : Neptune's Stones ), a pair of unusual rocks in the harbour of Lake Geneva . That height is defined from the average height of the Marégraphe in Marseille, the reference point for height data in France, and rounded to 373.6 m. The height was only measured accurately in 1902. As the height of the Pierres du Niton had been inaccurately measured in 1845 as being 376.86 meters, height information relating to this old horizon (for example in
64-453: The stream reaches the municipal boundary with Wettswil am Albis , where it is called the Fischbach . It passes to the west of the village and collects the waters of the roughly four-kilometre-long Fridgraben . It reaches the northern municipal boundary with Birmensdorf, where the stream snakes through the narrow Wüerital into the Reppisch valley. This valley was formed in the last ice age as
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