Schwarza (Black Forest)

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Schwarza
Highlighted course of the Schwarza

Highlighted course of the Schwarza

Data
Water code DE : 219882
location Upper Black Forest

Baden-Württemberg

River system Rhine
Drain over Schlucht  → Wutach  → Rhine  → North Sea
source Pump storage reservoir Schluchsee
47 ° 48 ′ 1 ″  N , 8 ° 11 ′ 0 ″  E
Source height approx.  890  m above sea level NHN 
foot of the Schluchsee dam
muzzle to wit Auer saw, Ühlingen-Birkesdorf , from the right and the Nordnordwestenin Schlücht coordinates: 47 ° 40 '44 "  N , 8 ° 15' 20"  O 47 ° 40 '44 "  N , 8 ° 15' 20"  O
Mouth height approx.  427  m above sea level NHN
Height difference approx. 463 m
Bottom slope approx. 25 ‰
length approx. 18.5 km 
from Schluchsee
approx. 29.1 km
from Q. Ahabach
Catchment area 114.78 km²
Discharge  (natural) at the mouth of the
A Eo : 114.8 km² 		MNQ
MQ
Mq
 MHQ
HHQ 		712 l / s
2.83 m³ / s
24.7 l / (s km²)
 34.59 m³ / s
175 m³ / s
Reservoirs flowed through Schwarzabruck , Witznau
reservoir , upstream: Windgälleweiher , Schluchsee
Small towns Ühlingen-Birkendorf
Communities Schluchsee , houses , Höchenschwand , Weilheim
Average bed slope: 25 ‰ from the Schluchsee dam
The Schwarza between the Witznau reservoir and Leinegg

The Schwarza between the Witznau reservoir and Leinegg

The Schwarza is the most important watercourse in the Schlucht river system , which drains parts of the southern Black Forest towards the Wutach and the Upper Rhine . After leaving the Schluchsee, it flows through a narrow and lonely forest valley in a south-easterly direction.

Geography and topography

course

Schwarza is the name of the river below the Schluchsee dam in the Breisgau-Hochschwarzwald district at about 890  m above sea level. NHN . Its natural upper course is the Ahabach, with which the Schwarza, including the lake crossing, is 29.1 kilometers long. This rises at about 1260  m above sea level. NHN in the southeast of the Bärhalde ( 1318  m above sea level ). Before the natural Schluchsee was dammed up to its present size and height (approx. 930  m above sea level ), the Ahabach flowed through the great Feldmoos in many windings before confluence with the lake , which is why the total length of the Schwarza was even greater at that time. Today , around 1.5 m³ / s of the runoff are branched off from the upper reaches of the Wutach, Seebach and Haslach rivers and fed into a long, concealed slope channel to the Windgälleweiher and then openly to the Schluchsee. Other tributaries of the Schluchsee are the Fischbach and the Krummenbach.

The Schwarza flows below the dam wall through a narrow valley cut up to 400 meters deep, largely free of settlement, through the basement of the Black Forest made of older granites . The upper part is a moderately wide trough valley because of its formation by ice age glaciers , below the largest right side stream, the Fohrenbach, it turns into a notch valley . The steepest section of the valley with rocky upper slopes is known as the Schwarzhalden . Despite the formation by ice age glaciers, the valley has a regular gradient. In the district of Waldshut, near Witznau (municipality of Ühlingen-Birkendorf ), the Schwarza flows into the Schlücht from the right .

Tributaries

The Schwarza has numerous small tributaries. By far the largest is the Fohrenbach , which tapers from the west a little less than five kilometers from the mouth of the river in the Schlucht, a little north of the Weilheim village Nöggenschwiel , which is 7.3 km long and forms part of the 115.9 km² catchment area of ​​the Schwarza 21.6 km² large sub-catchment area contributes.

Water flow

When leaving the Schluchsee, the Schwarza already has a water flow of around 1.5 m³ / s. At the confluence with the Schlucht, the Schwarza is longer (29.1 km compared to 21.3 km), drains a larger catchment area (114.8 km² compared to 86.4 km²) and is also significantly larger (2.8 m³ / s compared to that 1.8 m³ / s), so that hydrologically it is the main flow of the Schlucht system.

However, all the discharge values ​​mentioned refer to the natural discharge, i.e. without outlets and feeders. The Schluchsee-Werk, the operator of the hydropower plants, uses its water rights on the entire section of the Schwarza between the Schluchsee and the mouth near Witznau, where the water of the river flows largely through hydropower plants and the natural water flow is nowhere visible. Depending on the diversion for the Witznau power plant, there is often only a modest stream with an average of 0.03 m³ / s on the final section from the power plant to the mouth in the natural bed, compared to the ravine with 0.16 m³ / s dominates.

Lakes in the river

Schwarza with reservoirs as part of the Schluchsee pumped storage network

In addition to the Schluchsee, there are two other reservoirs in the Schwarzatal. These two equalization pools have short-term changing water levels and are therefore not suitable for recreational use.

Schwarzabruck reservoir

The Schwarzabruck reservoir is around 6.2 km, measured from the Schluchsee dam, downstream at around 725  m above sea level. NHN and is dammed by a 40 m high dam. The approx. 0.1 km² reservoir is around 500 m long and 275 m wide.

Witznau reservoir

The dam of the Witznau reservoir is about 1.25 km above the mouth of the Schwarza and the Schlucht. The reservoir reaches a width of up to 120 m and covers the former course of the river for a length of around 1.1 km. The surface of the lake reaches almost 0.1 km² and is approx. 470  m above sea level. NHN .

Use and development

The valley is mainly used for forestry. Due to the height and steep incline of the valley slopes, however, use is severely restricted in larger sections. On the valley slopes between Brenden and Berau, areas totaling over 300 hectares have been designated as protected forest since 1971 . The charming valley is little used for tourism, which allows an undisturbed experience of nature. The western route of the Black Forest Mittelweg hiking trail leads through the Schwarzatal.

Hydropower

The greatest importance of the valley lies in the use of water power. Together with its reservoirs, it forms the main axis of the Schluchsee-Werke AG pumped storage network , which extends from Schluchsee via the Schwarzabruck and Witznau pumping and power stations to the Rhine and Waldshut .

traffic

The Schwarza valley is only partially accessible for public transport by motor vehicle. A district road (K 6561) ends from the south after approx. 4.5 km. A narrow, very evenly rising road that follows the rest of the valley is only open to forestry, cyclists and hikers in addition to factory traffic.

Minerals

In the Schwarzatal, especially on the ridge between Schwarza and Mettma , there are deposits of fluorspar , which is used to produce fluorine and fluorine compounds, as well as deposits of galena , associated with silver , both of which were mined in the past ( see below ).

history

Schluchsee before the damming

The natural Schluchsee according to a map from 1847 superimposed with the extent at full dam after the construction of the dam wall in the 1930s.

Before the Schluchsee dam was completed, there was a natural “primeval lake”. The outflow of the Schwarza was about 500 m further north at what was then Seebrugg . This elongated lake (name in the sense of hose lake ) had a length of approx. 3 km (today approx. 7 km), an area of ​​1.03 km² (today 5.13 km²) and was about 900  m ü. NHN (today 930  m above sea level ).

Mining

Lead and silver mining

In the Schwarzatal, the ore veins that emerged on the slopes were mined in the Middle Ages , but probably much earlier. It was mined for silver , but this could only be obtained by mining the silver-containing galena. The name Silberberg below the town of Buggenried (Grafenhausen municipality) goes back to this mining. In a small side valley that branches off at the former hamlet of Leinegg below Leinegg Castle, old tunnels have been preserved above the Fohrenbachmühle , but they are not accessible.

In the Middle Ages, mining was carried out by the St. Blasien Monastery or a tax was levied on it, with the government of Upper Austria also involved. The extracted lead gloss was then smelted in the Wurkehof in Todtnau and the raw silver extracted was brought to a higher fineness in a hut in Freiburg im Breisgau . The use of silver as a coin metal in the Freiburg Mint is documented . In the Middle Ages, lead was used in the construction of windows, stone connections and sheet metal, among other things.

The mining of minerals came more and more to a standstill with imports of cheaper silver at the end of the Middle Ages. In the 20th century (especially around 1900, between 1922 and 1926 and around 1939) trial prospecting was carried out mainly in the eastern neighboring Mettmatal, but also in the Schwarzatal. However, they did not lead to renewed degradation.

Fluorspar mining

In the 20th century the demand for fluorspar was so high that the deposits in the Schwarzatal were mined between 1968 and 1970.

literature

  • District Waldshut (editor): Yearbook of the district Waldshut 2002 , vol. XXVII, DRW-Verlag, Karlsruhe 2002.
  • Rudolf Metz : Geological regional studies of the Hotzenwald . Moritz Schauenburg Verlag, Lahr. 1980.

cards

  • Topographic maps of the State Surveying Office Baden-Württemberg No. 8115 u. 8215, scale 1: 25,000.
  • Topographic map of the GRAND DUCHY OF BADEN based on the general survey of the Grand Ducal Military Topographical Bureau, Sect. XI.3 from 1847, scale 1: 50,000.

Individual evidence

LUBW

Official online waterway map with a suitable section and the layers used here: Course and catchment area of ​​the Schwarza
General introduction without default settings and layers: State Institute for the Environment Baden-Württemberg (LUBW) ( notes )

  1. ↑ Height according to the contour line image on the topographic map background layer .
  2. ↑ a b Height according to the blue lettering on the background layer of the topographic map .
  3. ↑ Length from Schluchsee after the stationing of the first tributary Kesselbach according to the layer water network (AWGN) , the additional small starting section from the Schlichsee exit up to there was measured on the background layer topographic map
  4. ↑ a b Length according to the waterway network layer ( AWGN ) .
  5. ↑ a b Catchment area summed up from the sub-catchment areas according to the basic catchment area layer (AWGN) .
  6. ↑ Catchment area according to the basic catchment area layer (AWGN) .

Other evidence

  1. ↑ Günther Reichelt : Geographical land survey: The natural spatial units on sheet 185 Freiburg i. Br. Federal Institute for Regional Studies, Bad Godesberg 1964. →  Online map (PDF; 3.7 MB)
  2. ↑ Geoportal Baden-Württemberg ( information )

literature

  • Topographic map 1: 25,000 Baden-Württemberg, as a single sheet No. 8114 Feldberg (Black Forest), No. 8115 Lenzkirch, No. 8214 St. Blasien, No. 8215 Ühlingen-Birkendorf and No. 8315 Waldshut Tiengen

Web links