Radolfzeller Aach
Encyclopedia
The Radolfzeller Aach is a right or north tributary
of the Rhine in the south of Baden-Württemberg
(Germany
).
It is approximately 32 km long.
is the Aachtopf
in Aach, the largest spring
in Germany
, at a height of 475 m above sea level
. The water emerges from a karst
cave. About two thirds of the water originates in the headwaters of the Danube
. Between Immendingen
and Möhringen an der Donau and in Fridingen
, water from the Danube disappears underground (this is known as the Danube Sinkhole
); this water reappears in the Aachtopf.
The river first flows through a number of nature reserves in the Hegau
area. This segment of the river is known as Hegauer Aach. It then flows South to Singen
, where it is known as Radolfzeller Aach. The last six kilometers of the lower course flow through a nature reserve called Radolfzeller Aach Ried. It flows into the northwestern part of Lake Untersee
(the Zellersee) between Radolfzell
and Moos
. At the mouth, the average discharge is 10 m³/s, making it the fourth largest controbutor to Lake Constance.
of 261 km². If one includes the catchment area of the Danube upstream of the Donauversinkung, then the Radolfzell Aach drains an area of 1.560 km² on days when all of the Danube's water disappears into the Danube Sinkhole.
s. Today, it drives several hydropower
stations. In some areas, nature restoration projects are being carried out, for example in Beuren an der Aach, where the borough of Singen
has set up a sediment
catching facility, catiching sediments and gravel carried by the river. Plans to release the sediments upstream of Volkertshausen were abandoned.
, Sandpiper and Green Sandpiper
. In the estuary, beavers establised themselves in 1998, after having been absent for 200 years. Hydromorphologically, the Radolfzeller Aach is a the lower end of trout and mullet territory. The dominant fish species in the Aach is the brown trout, as grayling are less shy and consequently more exposed to the feeding pressure of the large Cormorant
colony in the Radolfzeller Aach Ried. There are also noticeable stocks of some other endangered fish species, such as lamprey
and European bullhead
, who enjoy their protection close to the bottom of the river. In the lower reaches, we also find other species from Lake Constance.
, Beuren an der Aach, Friedingen, Hausen an der Aach, Singen
, Rielasingen-Worblingen
, Bohlingen and the Rickelshausen district of Radolfzell
.
Tributary
A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...
of the Rhine in the south of Baden-Württemberg
Baden-Württemberg
Baden-Württemberg is one of the 16 states of Germany. Baden-Württemberg is in the southwestern part of the country to the east of the Upper Rhine, and is the third largest in both area and population of Germany's sixteen states, with an area of and 10.7 million inhabitants...
(Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
).
It is approximately 32 km long.
Course
The source of the riverRiver
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
is the Aachtopf
Aachtopf
The Aachtopf is Germany's biggest natural spring, producing an average of 8,500 litres per second. Production varies seasonally and in response to the weather, but the spring never runs dry...
in Aach, the largest spring
Spring (hydrosphere)
A spring—also known as a rising or resurgence—is a component of the hydrosphere. Specifically, it is any natural situation where water flows to the surface of the earth from underground...
in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, at a height of 475 m above sea level
Sea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...
. The water emerges from a karst
KARST
Kilometer-square Area Radio Synthesis Telescope is a Chinese telescope project to which FAST is a forerunner. KARST is a set of large spherical reflectors on karst landforms, which are bowlshaped limestone sinkholes named after the Kras region in Slovenia and Northern Italy. It will consist of...
cave. About two thirds of the water originates in the headwaters of the Danube
Danube
The Danube is a river in the Central Europe and the Europe's second longest river after the Volga. It is classified as an international waterway....
. Between Immendingen
Immendingen
Immendingen is a town in the district of Tuttlingen in Baden-Württemberg in Germany....
and Möhringen an der Donau and in Fridingen
Fridingen
Fridingen is a town in the district of Tuttlingen, in Baden-Württemberg, Germany. It is situated on the Danube, 10 km east of Tuttlingen, and 23 km west of Sigmaringen....
, water from the Danube disappears underground (this is known as the Danube Sinkhole
Danube Sinkhole
thumb | Sinkhole in the Danube near Immendingenthumb | Schematic of the sinkhole locations and the route to Aachtopfthumb | Completely dry Danube riverbedthumb | right | Sink hole on the southern bank of the Danube, at the main sinkhole site below Immendingen...
); this water reappears in the Aachtopf.
The river first flows through a number of nature reserves in the Hegau
Hegau
The Hegau is a formerly volcanic landscape in southern Germany extending around the industrial city of Singen , between Lake Constance in the east, the Rhine River in the south, the Danube River in the north and the Randen—as the southwestern mountains of the Swabian Alb are called—in the west.The...
area. This segment of the river is known as Hegauer Aach. It then flows South to Singen
Singen
Singen is an industrial city in the very south of Baden-Württemberg in southern Germany and just north of the German-Swiss border.-Location:...
, where it is known as Radolfzeller Aach. The last six kilometers of the lower course flow through a nature reserve called Radolfzeller Aach Ried. It flows into the northwestern part of Lake Untersee
Untersee (Lake Constance)
The Untersee is the smaller of the two lakes that together form Lake Constance and forms part of the boundary between Switzerland and Germany.- Geography :...
(the Zellersee) between Radolfzell
Radolfzell
Radolfzell am Bodensee is a town in Germany at the western end of Lake Constance approximately 18 km northwest of Konstanz. It is the third largest town, after Constance and Singen, in the district of Konstanz, in Baden-Württemberg....
and Moos
Moos, Baden-Württemberg
Moos is a town in the district of Konstanz in Baden-Württemberg in Germany....
. At the mouth, the average discharge is 10 m³/s, making it the fourth largest controbutor to Lake Constance.
Catchment area
The Radolfzeller Aach drains a watershedDrainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
of 261 km². If one includes the catchment area of the Danube upstream of the Donauversinkung, then the Radolfzell Aach drains an area of 1.560 km² on days when all of the Danube's water disappears into the Danube Sinkhole.
Hydrology
In the past, the fast flowing water of the Radolfzeller Aach drove many watermillWatermill
A watermill is a structure that uses a water wheel or turbine to drive a mechanical process such as flour, lumber or textile production, or metal shaping .- History :...
s. Today, it drives several hydropower
Hydropower
Hydropower, hydraulic power, hydrokinetic power or water power is power that is derived from the force or energy of falling water, which may be harnessed for useful purposes. Since ancient times, hydropower has been used for irrigation and the operation of various mechanical devices, such as...
stations. In some areas, nature restoration projects are being carried out, for example in Beuren an der Aach, where the borough of Singen
Singen
Singen is an industrial city in the very south of Baden-Württemberg in southern Germany and just north of the German-Swiss border.-Location:...
has set up a sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
catching facility, catiching sediments and gravel carried by the river. Plans to release the sediments upstream of Volkertshausen were abandoned.
Fauna
Several endangered species of waterfowl can be found at the Radolfzeller Aach, including SnipeSnipe
A snipe is any of about 25 wading bird species in three genera in the family Scolopacidae. They are characterized by a very long, slender bill and crypsis plumage. The Gallinago snipes have a nearly worldwide distribution, the Lymnocryptes Jack Snipe is restricted to Asia and Europe and the...
, Sandpiper and Green Sandpiper
Green Sandpiper
The Green Sandpiper is a small wader of the Old World. It represents an ancient lineage of the genus Tringa; its only close living relative is the Solitary Sandpiper . They both have brown wings with little light dots and a delicate but contrasting neck and chest pattern...
. In the estuary, beavers establised themselves in 1998, after having been absent for 200 years. Hydromorphologically, the Radolfzeller Aach is a the lower end of trout and mullet territory. The dominant fish species in the Aach is the brown trout, as grayling are less shy and consequently more exposed to the feeding pressure of the large Cormorant
Cormorant
The bird family Phalacrocoracidae is represented by some 40 species of cormorants and shags. Several different classifications of the family have been proposed recently, and the number of genera is disputed.- Names :...
colony in the Radolfzeller Aach Ried. There are also noticeable stocks of some other endangered fish species, such as lamprey
Lamprey
Lampreys are a family of jawless fish, whose adults are characterized by a toothed, funnel-like sucking mouth. Translated from an admixture of Latin and Greek, lamprey means stone lickers...
and European bullhead
European bullhead
The bullhead is a freshwater fish that is widely distributed in Europe, mainly in rivers. It is a member of the Cottidae family, a type of sculpin...
, who enjoy their protection close to the bottom of the river. In the lower reaches, we also find other species from Lake Constance.
Communities
Villages on the Radolfzeller Aach include Aach, VolkertshausenVolkertshausen
Volkertshausen is a town in the district of Konstanz in Baden-Württemberg in Germany....
, Beuren an der Aach, Friedingen, Hausen an der Aach, Singen
Singen
Singen is an industrial city in the very south of Baden-Württemberg in southern Germany and just north of the German-Swiss border.-Location:...
, Rielasingen-Worblingen
Rielasingen-Worblingen
Rielasingen-Worblingen is a municipality in the district of Konstanz, in Baden-Württemberg, Germany. It is situated on the border with Switzerland, 4 km south of Singen, and 20 km east of Schaffhausen...
, Bohlingen and the Rickelshausen district of Radolfzell
Radolfzell
Radolfzell am Bodensee is a town in Germany at the western end of Lake Constance approximately 18 km northwest of Konstanz. It is the third largest town, after Constance and Singen, in the district of Konstanz, in Baden-Württemberg....
.