Drainage basin

• Endorheisches pool

The catchment area (including drainage area, drainage area, rainfall area of running water and river basin, at currents flow area ) is the area or the area from which a water system obtains its drain.

There is a basic distinction between the aboveground and the underground catchment area. The above-ground catchment area can be determined quickly usually by the topography of the terrain. The determination of which any differing underground basins is very complex and has not yet been carried out for most waters.

Definitions

The catchment area ( engl. drainage basin, drainage area, catchment area, river basin ) is an " area with a common outlet for surface runoff. ", Including groundwaters. The outflow of the drainage area is the receiving water. The framing of a watershed is the watershed so that the catchment area can also be defined as " area, which - with the exception of a point - is completely bounded by watersheds ." The projected onto the plane surface of the catchment area is called catchment area.

The area is mainly determined by the topographical and geological conditions. The water balance of a catchment area includes aboveground and underground drains. However, the latter can also get into another valley and thus the groundwater flow towards a different catchment area.

Catchments are always related to a certain point, usually a level ( no level should be present point, the reference point is, however, called the catchment ). The catchment area of a small watercourse thus usually refers to the point at which the water flows into a body of water of higher order.

The source and catchment areas of streams and small rivers are always part of a larger catchment area - namely that of waters into which they flow. A stream runs directly into the sea, it belongs to its much larger catchment area (see also the order of the waters, or tributary). In higher areas of a high mountain on the other hand represent the cirques and glaciers the beginning of catchment areas dar.

The effective catchment area results from the natural catchment area taking into account affected by supply and discharge areas. It is especially needed to calculate the outflow donations to ensure comparability.

Examples

Resin / Elbe

For the purposes of waters hierarchy has for example in the highlands of the resin each source river Bode a particular catchment area, which is part of the catchment area of the Bode. Their reservoir is in turn a part of the watershed of the Saale, that the Saale belongs to the catchment area of ​​the Elbe. The latter is already 148,000 km ² and is fed by several thousand spring-fed streams. That the Volga, however, nine times larger and contains 13 % of Europe.

Danube / Rhine

The Danube River has a catchment area of ​​817,000 km ², which those of the Rhine ( 185,000 km ²) exceeds by four times. In the Black Forest, however, the trade-off of about 2000 km ² the offing: the steep upper reaches of the Wutach, which was still flowing to the Danube about 50,000 years ago, eroded back to the source of the Danube, and from the north do the headwaters of the River Neckar like.

By Altmühltherme About Head artificial water is transferred from the catchment area of ​​the Danube in the catchment area of the Rhine. Another - albeit hidden - special feature can be found in the so -called Donauversickerung. There, a significant part of the Danube water flows underground to Lake Constance and the Rhine so and thus overcomes the European watershed.

In the Silvretta several tributaries of Rosanna and Trisanna be collected and carried off on European watershed away in the Silvretta reservoir and the Kops and thereby fed the Ill. The effective catchment area of ​​Sanna ( and consequently of the Inn and the Danube ) is thereby reduced by 164 km ², that of the Ill and the Rhine so that the same amount increased.

Watersheds, canals and power plants

The catchment areas of various non-intermeshing opens Direction waters are separated by watersheds which run mostly along the ridgelines of the site. In some places, but these can vary by geological features significantly the course of the terrain surface.

In the lowlands can be overcome for the purpose of shipping the catchment areas with the help of channels, you can not do without locks or boat lifts because of the height differences in the rule. Because of such structures, there are also channel systems that overcome large differences, such as the Rhine -Main -Danube Canal.

While such traffic routes takes place net little water exchange, it is in many projects in the mountains the main concern. Such transitions take place at the storage power plants and for the purposes of water management. The often steep, natural boundaries of river basins can be overcome with pumping stations through tunnel-like tunnels, but also with exposed wires, and sometimes up today with Roman aqueducts. Localized differences in height and valley crossings can be mastered with culverts.