General

Цcosystem flow (river)


Information about the river watercourse:


To the FlieЯgewдssern count open (in the sense of non-underground) waters, which, in contrast to the standing waters (for example lake) are in constant, flowing motion. Natural river waters are in ascending order: trickle, creek, River and electricity.
The delineation of the individual rivers is very uneven in the literature. Depending on the author, the criterion is the length, width, speed or catchment area.

Upper, middle and lower reaches

Flow waters or rivers are divided between the beginning (source) and end (mouth) into upper, middle and lower reaches:
1. sourceAt the source the river springs. Often, various smaller sources converge and form with increasing length an ever larger stream.
2. headwaters: The upper reaches describe the environment from the beginning of the spring. The steep terrain leads to enormously high flow velocities, which favor the formation of a V-shaped valley.
3. middle course: The flux course is characterized by extensive flux loops, so-called meanders. Centrifugal force permanently to B
4. underflow: There is hardly any current to register in the lower reaches, as there are no more havoc. For this reason, the river in the lower reaches also widest. The banks are mostly overgrown with plants.
5. Mьndung: Transition from the river into the sea (river delta). The typical delta with numerous estuaries results from the deposits transported by the river. Over time, mud, sand and gravel are deposited at the mouth. At some point, the river can no longer 'overflow' these deposits and therefore flows past them left and right. This process is repeated many times and provides long term for a river delta.

Subdivision based on the Leitarten in FluЯ

Another way of dividing the river into individual areas is to divide them by the types of codes. A guiding principle is understood to be the species that predominantly occurs in a habitat. An important condition here is that the Leitart also does not occur under any other similar environmental conditions, since otherwise it would not be possible to conclude clearly from species to habitat. The environmental conditions in the different areas of the river are relatively stable, which means that the various species of animals only inhabit the areas favorable to them. Essentially, five sections or fish regions are important:
1. Trout RegionBetween the source and the upper reaches the water is clear and low in nutrients. High scavenging causes a high flow rate, whereby the oxygen saturation of the water is close to 100%. The soil is rocky according to the mountainous environment. Guineafish species: trout
2. Дschen region: The water in the upper reaches is still cool, clear and low in nutrients. The soil consists of rock and coarse gravel. Guineafish species: Дsche
3. Barbel regionThe barbel region in the middle reaches of the river is characterized by a moderate current. The water is a bit warmer and enriched with nutrients, i.a. from washed out rocks and fallen leaves. As the flow length increases, the gravel soil becomes increasingly sandy. many plants, fish type: barbel
4. Bream Region: The now slow flow rate leads to muddy deposits in the lower reaches. The water is dull and rich in nutrients, with only a little oxygen. The multiplicity of microorganisms in this flow area consume a large part of the oxygen. Guineafowl: bream
5. Ruffe region: In the Kaulbarschregion the river ends in the sea, which is why it comes to a mixing of fresh water and salt water (= brackish water). The current is very weak. Sand and mud are deposited on the bottom of the river bottom. Nutrient-rich water promotes extensive plant growth at the slow flow rate on the banks. At the mouth, a river delta often develops. Guineafowl: ruff

Self-cleaning of watercourses

Naturally introduced impurities such as e.g. Leaves, dead animals or excretions can reduce a river without any problems. In the normal case, the substances introduced are consumed under oxygen consumption by the microorganisms in the river. If there is a lack of sufficient oxygen (anaerobic conditions), decomposition of organic matter produces ammonia and hydrogen sulfide, which are highly toxic to animals in the water. Large amounts of unnatural (in the sense of the enormous amount of organic compounds), introduced wastewater, lead in the course of decomposition to enormous oxygen consumption and thus ultimately to the development of ammonia and hydrogen sulfide.
Not only the load of organically introduced material can be a serious problem in the river flow. If, for example, heavy metals (lead, cadmium, mercury) get into the river, they can irreversibly poison the river. Because with deposits of heavy metals, the water flow has practically no possibility for self-cleaning. Accordingly, too much stress leads to the death of almost all organisms in the river.