Stream

A stream is a small flowing natural waters. Larger rivers are called rivers. A precise definition is difficult and depends on the context. Thus, e.g. navigability, the outflow (less than 20 m³ / s) or the width ( less than 5 m) can be used as a criterion. The lower average water depth and the smaller waters cross section and the consequent frequent direct interactions between water bodies, river bed, banks and riparian vegetation delineate the character of the stream of the a river.

Understanding

Streams are in hydrological jargon small river or channel. There are so -called perennial flume that constantly run water, and periodic or episodic flume, which only temporarily, cyclically or irregularly occur, such as the stone trenches of the limestone areas in Thuringia or other aboveground Karstgerinne.

Characteristic of the stream, the flow rate of the water, the temperature conditions, the oxygen content, the light conditions, which occur in the stream organisms and the environmental impact of chemicals. Furthermore, it is characteristic of a stream, that its water level rises or falls, substrates contained in the stream are shifting and the course of the stream may change over time.

The flow rate is influenced by present in the creek stones, dead wood and small islands, strictures, local depressions or shallower.

In the horticultural technology artificial streams are created under design aspects.

Terms and onomastics

Limnology distinguishes three basic types of regional streams, the mountain, the low mountain and lowland stream. An almost never -ending, arising from sources in forests stream is referred to as forest stream.

Bach formed from OHG pah Pl pechi, MHG bach beche Pl. Place names on - stream are the earliest of the high medieval Conquest, probably between the 11th and 13th centuries, to you, but much later developments are common.

The old concept of flow ( flow, flow ) is still in use in Brandenburg and Berlin, for example, for the Tegeler Fliess, the pepper and flow in the Spreewald. In flaring regions known today leveling but also as trenches are to derive the rainwater from fields ( drainage ). These waters dry in low rainfall months of often. For the Low German equivalent see Fleet.

System

The hydrology in connection with the orography examine the variety of forms in riverine, and try to agree on certain basic types: If one looks at the total distance of a stream, so can be a upper reaches, a middle reaches and lower reaches differ. In a typical model brook course these sections correspond to the three basic forms mountainous, upland and lowland stream. Streams show but naturally with a diverse history in small forms of the source route to be almost standing sections with backwater areas and waterfalls or marsh sections, constrictions with Klamm character or fords as shallow water far beyond the normal width, to infiltration, where the waters under the earth plunges, and there continues to flow, or is lost in the groundwater.

Mountain stream

In mountain streams prevails because of the larger gap a stronger flow, which ensures favorable oxygen conditions, but also for a strong erosion. The river bottom is very rocky. Mountain streams carry much sediment with it. The occurring in mountain animals are very sensitive to oxygen deficiency. Water plants are not as good as before.

Low mountain

In central mountain streams, the slope and thus the flow decreases. In addition to erosion, it also sedimentation occurs. Smaller islands and gravel banks emerge again and again in different places. The emerging here varied retail spaces offer the most diverse aquatic life a livelihood. Pointer type is the brown trout.

Lowland stream

In lowland streams the gradient is at its lowest. The water flows gently into meanders through there. Sedimentation and nutrient richness are quite large, so that the river bed is penetrated relatively sandy and organic material. At low flow numerous aquatic plants in the stream occur.

Typical low mountain ( Malham Beck, Malham in North Yorkshire, England): free flow, sills

Lowland stream (cross creek at Altenberg ( Obersasbach ), in the nature reserve Hainberg ): sand quarry, Driftwood

Bach in the Norwegian Fjell on the plateau of Hardangervidda

Bach Ambro in the Monti Sibillini National Park

Human intervention

Streams, as well as other waters, are ordered by their use or Hazardous for the people going out of them as "peaceful" or referred to as a mountain stream, where the latter measures are appropriate for flood protection in urban terrain.

The natural bed of the streams in Central Europe has generally been greatly changed by human intervention. Bach regulation, and the discharge of pollutants in urban areas have led to considerable disruption of the natural history and to an impairment of self-purification industry-related watercourses. Also, the over-fertilization of fields in brook near by intensive agriculture in many places customary for increased levels of pollutants in the creek. The phosphate and nitrate supply leads to increased algae growth, the discharge of effluent to a proliferation of bacteria.

Artificial streams

The word stream shall mean a course of a natural creek and artificial watercourses in horticulture. Streams are often sometimes made ​​in the garden design in conjunction with garden ponds without discharge into a standing body of water. The water supply is generated by a pond pump. The substrate of the stream is sealed by pond liner, unless it is made industrially manufactured creek shells.