Alluvium
As precoating in is Geosciences the deposition of fine sediment by directional or flow change of rivers designated. It mainly takes place on the so-called slip slope , the bank inside the curve in the shadow of the river. The material, which usually also contains some earth or humus , is transported by the water when the current is fast and when it subsides, it can settle on shallow banks through sedimentation .
The deposition of sludge , which consists of even finer particles and requires almost stagnant water, is not included in the term, while the formation of sand and gravel banks is also promoted by turbulence (or intentionally) by groynes . During floods , the accumulation of rubble , uprooted trees and dead wood is also referred to as alluvial deposits . It can block bottlenecks in streams and rivers or endanger the construction of bridge piers . The removal of wedged wood from Klausen used to be a great danger for the woodworkers when the wood was washed away . Soil erosion can also act as an alternation between runoff and alluvium , especially of deeply plowed soils with intensified agriculture . Long-lasting precipitation, wind or heavy rain then deposit the humus soil components down the valley in often thick layers, which later develop into Kolluvisol soils.
Chemicals or oils washed up, for example after an oil tanker accident, can also pollute the coast and pose a health risk for people passing by.
literature
- Gustav Braun : Development history studies on European lowland coasts and their dunes . Salzwasser-Verlag 2014, p. 7 ff. ( Online )
- Bernhard Studer : Textbook of physical geography and geology . Verlag von JFJ Dalp, Vienna 1844, pp. 191 ff. ( Online )
- Hermann Wagner : Textbook of Geography: Second part: Physical geography . 1921, reprint in Salzwasser-Verlag 2015, p. 353 ff. ( Online )
Individual evidence
- ↑ Recommendations for the closure of coasts after the washing-up of liquid cargo residues , updated information No. 030/2015 of the Federal Institute for Risk Assessment of September 14, 2015.