2016-02-12
Introduction
As we know, the “Critical Zone” is the zone that extends from the vegetation outer limits to the lower limits of groundwater. This zone is important for all life on the Earth. It provides most of the ecosystem services on which societies depend. In this case, erosion processes are dangerous enough for the Critical Zone and they must be timely identified.
Discussion
The erosion is a quite dangerous geological process, as it leads to rather unfortunate consequences (for example, structural failure, displacement, shrinkage of the foundation, and some others). This process leads to the destruction of the rocks (soils) due to the action of surface water flow, accompanied by winds. A separation, and even flushing debris materials are specific processes of erosion. The ravages of erosion depend on the mass of surface water and its velocity. Engineering and geological surveys are conducted on a mandatory basis in areas, which are inclined to dangerous geological processes. Erosion refers to exogenous destructive processes.
Forms of water erosion: planar (surface); linear (or gully); jet erosion (it is intermediate between the planar and linear). The main natural factors, which influence the development of erosion processes are climate, relief, forming soil rocks, vegetation. According to another classification, there are two kinds of erosion processes: water and wind. Soil erosion is expressed in a certain combination of natural conditions and changes economic activity of humanity.
Water erosion occurs only on the slopes. Streams of water after rain and rainstorms, with melting of snow do not have time to soak into the soil, wash its particles and form ravines. The powerful streams of water usually form deep ravines (gullies). They reduce the arable land area, creating inconveniences for further agricultural work. The agricultural crops can be damaged or completely destroyed due to strong water flows on steep slopes. The most fertile ground layer can be washed away. Eroded soils require large costs on cultivation. Especially costly work associated with fixing the ravines. Water erosion is particularly dangerous in mountainous areas.
Wind erosion occurs mainly in the arid steppe areas where strong winds are frequent. The soils are often characterized by light texture and vegetation cover is weak or non-existent. As a result of wind erosion, the upper, most fertile layer of soil is blown out, carried by the wind over long distances. The strong wind can fill the crops elsewhere.
Severe wind erosion occurs in areas where winds blow at high speed, causing dust (black) storms. They affect the forest plantations, land reclamation facilities, roads and settlements. But the main damage that dust (black) of the storm brings is a sharp decline in soil fertility, loss of crops and harvest. It should be noted, that accelerated erosion is observed in the areas of dissemination of gray forest soils, black soils (with high amount of humus), chestnut soils in agricultural areas of the taiga-forest zone, as well as in the mountainous areas.
Let’s analyze which type of erosion processes is the most dangerous for the so-called Critical Zone. For example, linear erosion is soil erosion in depth with the formation of potholes and deep gullies, developing into ravines. It is a water erosion subspecies. This erosion is caused by the significant watercourses, which focus on narrow sections of the slope. They lead to the complete destruction of the soil. Such type of erosion can be considered as the most dangerous and is the first to be eradicated. Linear erosion operates mainly in small areas and leads to the dismemberment of the Earth’s surface. This process is also called “river erosion”, as operates mainly in the valleys of the rivers. This leads to the destruction (run-off) off the coast. In this case, the base coat is broken and its basic physical and mechanical properties are disrupted. It is mandatory to conduct hydrological and geological investigations if it plans to build houses in this area.
In this situation, the US pays great attention to the protection of the Critical Zone It is a crucial, because it is where water flows, soils are formed from rocks, and terrestrial life flourishes. There are critical zone observatory network that operates in the US. Its main goal is to protect Critical Zone from complete destruction and regular monitor the soils, which are used in agricultural work.
Conclusion
In conclusion one can say that linear water erosion can be considered as the most important, because it leads to complete destruction of soil structure. Timely inspection of the area can significantly reduce damage by erosion processes. According to the geological report design organizations will be able to arrange protective security measures or to hold special measures to prevent the destructive effects of erosion.
Bibliography
Banwart, S.A., K., Lehnert, N.P, Nikolaidis, K.V. Ragnarsdottir, M. Goldhaber, C., Duffy, W.E. Dietrich, O., Chadwick, S.L Brantley, and A., S. Bernasconi. Sustaining Earth’S Critical Zone Basic Science And Interdisciplinary Solutions For Global Challenges. UK: The University of Sheffield, United Kingdom, 2013. http://www.czen.org/sites/default/files/Sustaining-Earths-Critical-Zone_FINAL-290713.pdf.
Nsf.gov.”Critical Zone Observatories | NSF - National Science Foundation”. https://www.nsf.gov/funding/pgm_summ.jsp?pims_id=500044, 2016.
