Radau (river)

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Racket
Radau waterfall near Bad Harzburg

Radau waterfall near Bad Harzburg

Data
Water code DE : 48218
location Harz , District of Goslar , Lower Saxony ( Germany )
River system Weser
Drain over Oker  → Aller  → Weser  → North Sea
River basin district Weser
source in the Harz near Torfhaus
51 ° 47 ′ 55 ″  N , 10 ° 32 ′ 23 ″  E
Source height approx.  800  m above sea level NHN
muzzle near Vienenburg in the Oker coordinates: 51 ° 57 ′ 28 "  N , 10 ° 34 ′ 21"  E 51 ° 57 ′ 28 "  N , 10 ° 34 ′ 21"  E
Mouth height approx.  130  m above sea level NHN
Height difference approx. 670 m
Bottom slope approx. 32 ‰
length 21.1 km
Catchment area 59.27 km²
Discharge at the Harzburg
A Eo gauge : 18.3 km²
Location: 14 km above the mouth 		NNQ (06.09.2003)
MNQ 1926/2014
MQ 1926/2014
Mq 1926/2014
 MHQ 1926/2014
HHQ (04.06.1981) 		36 l / s
86 l / s
415 l / s
22.7 l / (s km²)
 7.49 m³ / s
30.3 m³ / s
Drain MQ
 790 l / s
Left tributaries Baste, Tiefenbach, scoring Bach , bleach , wealth Kuhle Bach, Gläsecke , Mühlebach, Teufelsbach
Right tributaries Abbentränke, Koblebornsgrund, Lohnbach, brook from Kaltes Tal, Stübchenbach
Medium-sized cities Bad Harzburg
Small towns Goslar-Vienenburg
Radau waterfall
Radau near Vienenburg with the bridge of the former Vienenburg – Langelsheim railway line
Artificially created slope ditch to the Radau waterfall

The Radau [ ˈʀaːdaʊ ] is a 21.1 km long, southern and orographically right tributary of the Oker in the Lower Saxony district of Goslar . It rises in the Harz Mountains , flows through the Radau valley, Bad Harzburg and Vienenburg that it created and shortly afterwards flows into the Aller tributary Oker.

etymology

The name Radau is of Germanic origin and goes back to ancient Germanic * hradaz "fast, hurried, later: straight" and the ending -au for Aue, so Radau basically means "faster, straight river". The river was mentioned in 1308 or 1325 as Radowe , 1570 as Radow , 1578 as Radaw and also in 1578 as Radau .

course

The Radau rises in the Upper Harz in the local area of ​​the Altenau district of Torfhaus . Its source is in the Torfhausmoor (also called Radaubornmoor ) near the Lerchenköpfe ( 821  m above sea  level ) at an altitude of around 800  m .

A few meters below its source, the Radau flows into the Harz National Park . In the headwaters and in the further course in the Radaubbruch numerous raised bog ditches flow towards it. After the confluence of the bastion coming from the left , where it changes from the National Park to the Harz Nature Park , the typical low mountain range river enters its deeply cut Radau valley. After the confluence of the Lohnbach , which flows from the right , from where it runs along the border of the national park a few meters to the east in the east and the nature park in the west, and the Tiefenbach coming from the left, the water is transferred from the river to the artificially created Radau waterfall . At its foot, the Radau has already covered 400 meters in altitude. At the subsequent gabbro quarry, it crosses under federal highway 4 for the first time .

At the forester's house Radauberg, the Radau flows into populated areas and a little later into the spa area of ​​Bad Harzburg; in the process she leaves the Harz National Park and Nature Park for good. In the Harzburg urban area, where the river passes the Großer Burgberg ( 485  m ) to the east, its bank is largely paved with ashlar. To the north of the state road L 501 (Herzog-Julius-Straße), the recently heavily canalised Stübchenbach flows into the Radau, which is the northernmost orographically right larger feeder. In the district Bündheim opens in Bleichenstraße the bleach the inflowing also left in the street to the pastures of abundance Kuhle stream and at the Bahnhofstrasse in Schlewecke Gläsecke (Mühlenbach) a.

In the Mathildenhütte district, the Radau passes the Radauanger settlement on the left, including the municipal sewage treatment plant. Below Gut Radau and the Radaumühle, where the river leaves the Bad Harzburg urban area, it only has to cover about 50 meters in altitude to the mouth through an extensive gravel quarrying area. Below the mining area, the Teufelsbach coming from Harlingerode from the left and, further down, two brooks from the Radauer Holz flow into it.

The Radau then flows through the Goslar district of Vienenburg and to the northeast of it and shortly before the district of Wiedelah at the east end of the Harly Forest at 130  m above sea level, it reaches the Aller tributary Oker, which comes from the west .

Radau waterfall

On the western slope of the Winterberg ( 585.3  m ) is the artificial Radau waterfall, also called Radaufall ( ⊙ ). To feed the around 23 meter high waterfall, a 1000 m long branch channel of the Radau, the "slope ditch" , was created from a point around 300 creek meters northwest below the confluence of the Lohnbach ( ⊙ ). Below the waterfall, the water flows back into the noise.

The bike crash including the slope ditch was set up in 1859 at the instigation of Philipp August von Amsberg (founder of the Ducal Braunschweigische Staatseisenbahn ) and the state bathing commissioner Hermann Dommes to stimulate tourism and is today an attraction due to its location close to Bundesstraße 4. Located on site the Waldgaststätte Radauwasserfall , a mushroom kiosk and the EMMA children's railway integrated into the landscape .

rafting

The Radau has been used to float tree trunks and peat on wooden pallets since the Middle Ages . The water was dammed up with the help of six raft sluices. The material to be rafted, which had previously been deposited in the river, drifted downstream with the additional surge of water after the sluices were opened.

After the construction of the railway line, the wood was transported by rail and rafting was abandoned.

Water management

Since 1981, the Harzwasserwerke have been operating a drainage structure downstream of the waterfall, which can cut off partial runoff of the Radau through the Radau tunnel to the Romkerhalle hydroelectric power station and from there through the Oker-Grane tunnel to the Granetalsperre . The Radau provides 9% of the drinking water treated there. In addition, this structure serves to relieve Bad Harzburg from flooding.

When it was built, the drainage structure was equipped with a fish ladder , which, however, was not very well received by brown trout. As part of the extension of the operating license, the NLWKN demanded an improvement in the situation, which led to the redesign of the fish pass.

Water quality

The river is largely natural in the upper reaches, but is paved in the bank area below the waterfall. This is partly due to the earlier use of the Radau for rafting and in parts to the urban area around Harzburg. As part of the structural improvement, measures such as the dissolution of barrages by bottom sliding have already been carried out.

The biological quality is rated as quality class I , especially in the upper reaches of the Radau . Mayflies and stone flies have been observed there. In the further course the quality class is indeed worse due to the various discharges, but "since 1986 19 species from the Lower Saxony Red Lists have been observed".

In the NLWKN's water body data sheet, the chemical and biological status is assessed as “good” and the ecological status as “moderate”. The structural quality is more in the middle range. Overall, the Radau water body is one of the few bodies of water that has been assigned to the very high priority category "Preservation, protection, high or very high settlement potential without any recognizable threat".

Traffic and walking

Along the Radau runs above Bad Harzburg the federal highway 4 with an approximately 3 km long section and between Bad Harzburg and Vienenburg the railway line Braunschweig-Harzburg . In Bad Harzburg, the river is crossed by the European long-distance hiking trail E11 .

gallery

See also

Web links

Commons : Radau  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b Map services of the Federal Agency for Nature Conservation ( information )
  2. ↑ a b Land survey of Lower Saxony: topographic map 1: 50: 000 , status 2000, software package Top50
  3. ↑ a b c d Braunschweig district government / NLWKN : Inventory of the implementation of the EU Water Framework Directive, surface waters, Oker processing area , draft of November 22, 2004, table 2. Source, accessed on October 2, 2012
  4. ^ Deutsches Gewässerkundliches Jahrbuch Weser-Ems 2014. Lower Saxony State Agency for Water Management, Coastal and Nature Conservation, p. 179, accessed on October 4, 2017 (PDF, German, 8805 kB).
  5. ↑ Word root * hradaz in the English-language Wiktionary , accessed on February 14, 2018.
  6. ^ Albrecht Greule , Sabine Hackl-Rößler: German book of waters names . Etymology of the water body names and the associated area, settlement and field names. De Gruyter, Berlin 2014, ISBN 978-3-11-019039-7 , pp.  422 ( limited preview in Google Book search).
  7. ↑ LGLN: Digital Topographic Map 1: 25,000 , navigator.geolife.de, May 2013
  8. ↑ NLWKN : Bad Harzburg: Authorization for the Radau transition renewed , press release of November 22, 2006, accessed on the NLWKN website on May 20, 2013
  9. ^ Goslarsche Zeitung: Free path for the Radau salmon ( memento from June 30, 2013 in the web archive archive.today ), from August 13, 2009, accessed on May 24, 2013, from goslarsche.de
  10. ↑ NLWKN : Water quality report Oker 2002 , Braunschweig, October 2002.
  11. ↑ NLWKN : Water body data sheet 15006 Radau (as of December 2016), with recommendations for action, from Umweltkarten-niedersachsen.de (PDF; 9.5 MB), accessed on April 25, 2017.
  12. ↑ NLWKN : Prioritaeten_WK_Gewaesserstrecken_Nds_pdf.pdf , Annex to the guideline for planning measures for surface waters, March 31, 2008, accessed on May 24, 2013