Grien Island
| Grien | ||
|---|---|---|
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| Waters | Limmat | |
| Geographical location | 673 078 / 251811 | |
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| length | 1,100 km | |
| width | 0.110 km | |
| surface | 0.08 km² | |
| Highest elevation | 388 m | |
| Residents | uninhabited | |
The Grien Island is an island in the city of Dietikon in the Swiss canton of Zurich . It is between the Limmat in the east and one channel of the power station Dietikon the power stations of the Canton of Zurich in the west. The power plant occupies the entire southern half of the island, while the northern part is mainly forested.
The island is 1100 meters long, but only a maximum of 110 meters wide. The area is around eight hectares. The highest point is 388 m above sea level. M. in the south of the island at the road bridge between Dietikon and Fahrweid , the lowest point is in the extreme north of the island at 380 m above sea level. M.
history
The Grien area used to be a swampy area that was constantly flooded. At that time the Limmat flowed further east in what is now the Au bei Fahrweid area. The Dornau river island was also located here , the outlines of which can still be seen today through the oxbow lakes . In the north there was a peninsula, which today partially forms the northern part of the Grien and on which remains of Roman walls were found. In the southern part of the area there was a ferry since 1832 , which crossed to Weid until 1895 and gave the hamlet the later name Fahrweid.
The area of Grien only became an island later. On October 19, 1856, JH Boiler and Dr. J. Hegnauer in Fehraltorf submitted an application to the government council to be allowed to build a weir , an 880 meter long canal and a hydroelectric power station for the operation of a cotton weaving mill . This application was approved on March 14, 1857, but with the condition, among other things, of building a lock for shipping . This was unusual because the year before the Zurich – Baden railway line was extended with the Baden – Aarau line to Brugg and a railway network was slowly taking shape.
Construction work began in 1857 and after about three years the 350 meter long upper water canal, the 250 meter long lower water canal and a machine house were completed and put into operation. This gave rise to today's island, which at that time was roughly the same as it is today. This also created new conditions for the ferry connection, which now had to cover a shorter distance. From Dietikon, a path with a bridge led to the southernmost part of the island, on the east side of which the ferry was located.
It was found, however, that the simple stone pouring did not lead to enough water into the canal and so a 30 centimeter high threshold wall was built. The first water measurement took place in 1864 and showed a processed quantity of 1.7 m³ / s with a gradient of 2.07 meters, which corresponded to a gross output of about 50 hp. For this a water interest of 145 francs had to be paid. The net power, on the other hand, should have been around 36 hp.
Small adjustments were made time and again in order to meet the increased demands or to remedy deficiencies identified in the company. In addition, sludge was repeatedly deposited in the upper water channel, so that the entire weaving mill with 236 looms had to be shut down to remove it. To counter this, an idle channel was built in 1866, which was 220 meters long. The weir was rebuilt in 1870 and 1877. The regulations were not always followed and the factory owners were even sentenced to a fine for unauthorized changes. An unapproved stone dam also had to be removed.
In 1880, after several floods, the construction work to correct the Limmat between Oetwil an der Limmat and Zurich began . The section between Dietikon station and the Reppisch estuary was started in 1887 and completed in 1888. Changed drainage and gradient conditions then forced the factory owners to make further changes to the weir. For this purpose, a small DC generator was put into operation in 1888, which was the first in the entire Limmat Valley .
In 1897 the canton opened the first Limmat bridge between Dietikon and Fahrweid, after which the ferry lost its purpose. The next bridges over the Limmat were not far away upstream at Unterengstringen , but the next bridge downstream was not until Wettingen in the canton of Aargau . In 1901 the canal bridge was strengthened and in 1929 a further expansion was necessary as a result of increasing road traffic and the construction of the Ueberlandstrasse . On this occasion, the axes of the two bridges were also laid in a straight line.
In 1908 the EKZ, founded in the same year, took over the plant. The infrastructure was expanded for the first time in 1913, and further buildings followed in 1930. The northern part of the island was opened only in 1940 with a path, but already the Grien at the confluence of Reppisch and tailrace was previously in the far north, a pedestrian bridge, now called Reppischbrücke is a listed building. Initially there were only two separate forest areas, until almost the entire northern part was afforested in the early 1970s.
See also
swell
- Geoserver of the Swiss federal administration with the layer time travel - map series
- New Year's Gazette from Dietikon 1961
Individual evidence
- ↑ a b c Geoserver of the Swiss Federal Administration ( information )
- ↑ a b Dorfchronik Geroldswil Page of the municipality of Geroldswil
- ↑ a b Dietikon river power station Electricity works of the Canton of Zurich