The water erosion It is the wear or loss of material that causes the physical and chemical action of water on solid surfaces. This is due to the physical force and the diluting action of water when acting on any surface according to its hardness..
The erosive action of the water develops in three phases, beginning with the detachment of the material, then its transfer and finally its deposition (sedimentation). The intensity and scope of this erosive action depends on the cohesion of the particles that make up the surface on which the water acts..
The means of action of water erosion are physical and chemical, the mass and speed of the water being among the first. While among the seconds acidity stands out as an important factor.
While the forms of action are due to rain and water runoff, and the factors that condition it are climate, substrate, vegetation and topography. The most important consequence of water erosion is part of the modeling of the landscape, by wearing down rocks and undermining land.
The action of water erosion over time has excavated deep valleys and shaped mountains. In addition, the material originating from said erosion has filled in depressions and formed plains..
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Water erosion begins with the separation of particles from the erodible surface due to the impact of water. Then these particles are transported, they settle or settle in a certain place.
The properties of water and certain factors that determine its action affect this process. From the physical properties of water, its mass, movement and speed stand out, exerting a mechanical action on the surfaces it impacts..
From a chemical point of view, the composition of water also plays an erosive role, associated with its acidity and the alkalinity of the surface on which it acts. Among the factors that determine the erosive effect are the climate, vegetation, topography and substrate.
The climate of a region directly affects the occurrence and intensity of water erosion, particularly rainfall and humidity. Precipitation supplies the agent of water erosion (water) and determines its frequency and intensity.
For example, in an area with a tropical rainy climate with rainfall greater than 7,000 mm per year, water erosion is high..
In the case of soil water erosion, the role of vegetation cover is essential. This is because the vegetation exerts a buffering effect of rainwater on the soil and rocks, reduces runoff and favors infiltration..
If the soil lacks vegetation, the water impacts directly with all its kinetic energy, disaggregating the clods. On the other hand, the water in the soil runs off freely, dragging particles.
The shape of the land surface, especially the slope of the land, is essential for water erosion. This is due to the fact that the greater the slope or inclination of the terrain, the faster the water that runs off will reach..
In a terrain with a high slope, for example the side of a mountain without vegetation cover, the water reaches a great speed.
The substrate on which the erosive action is exerted is important, since depending on its characteristics the erosion will be greater or lesser. In the case of soil and rocks, their structure and texture make them less or more susceptible to water erosion..
Thus, the less organic matter in the soil, the higher the content of sand and calcium, the more likely it is for water erosion. This is because its aggregates are less resistant to the mechanical and chemical action of water..
In addition, if there are calcareous components, a water with high acidity dissolves them, facilitating the dragging or transport. Similarly, the action of water on calcareous or sandstone rocks is different versus granite rocks, where the latter resist erosion better.
On the other hand, water erosion on infrastructures, such as buildings or monuments, also differs according to their composition..
Water erosion acts through the impact of raindrops on a surface and then by running off due to the mechanical friction that it generates.
This refers mainly to the wear action exerted by the drops of water when falling from high altitude on the earth. Its kinetic or movement energy will be proportional to the amount of water, the size and frequency of the drops and the duration of the rain..
This periodic process of the impact of drops with force on the surfaces is exerting a wear action. Likewise, there is erosion due to direct impact in the case of waterfalls or waterfalls or due to the action of sea waves on the coasts..
Once on the ground, the water moves depending on its quantity and the topography of the land. In those cases in which the slope or slope of the terrain is low and the terrain is flat, a laminar flow occurs (displacement in the form of a sheet).
This water erosion is the least evident, but it has a great effect on the soil because the water slowly carries away the organic matter and the finest soil particles. Thus, coarse particles such as sand remain and the soil loses its ability to retain water and fertility..
They are large bodies of water moving in a turbulent way through steeper terrain that undermines the terrain. Therefore, gullies and channels are being created, its immediate effect and in geological times this erosion is responsible for the formation of large valleys and rivers..
It is about displacement of masses of mud or mud due to the saturation of water of soils combined with steep slopes. This produces the so-called landslides, when the water in a superficial layer of land is saturated on a slope, increasing its weight..
In this way, they fall by gravity, dragging more soil, rocks and vegetation in their wake. This is facilitated when the soil layer is on a layer of impermeable rock..
This type occurs mainly in calcareous areas, where the water penetrates the soil and dissolves the rock. Therefore, underground cavities are formed until they constitute large cavernous systems.
In these there are even underground lakes and rivers, and sometimes, the roofs of these caves collapse, forming open cavities..
Water erosion plays a relevant role in the configuration of the natural landscape such as the formation of valleys, rivers, filling of depressions and the formation of alluvial plains. The latter product of the sedimentation of the particles carried by the water.
Water erosion is one of the main causes of soil loss in both natural and agricultural environments, with serious consequences for food production. Due to the rapidity with which the soil is lost and the slowness of the processes of its formation, the areas become deserts (desertification process).
The landslides or mud runoffs have been the cause of great tragedies with human and material losses. An example of this was the Vargas Tragedy that occurred off the coast of Venezuela in 1999, where between 10,000 and 30,000 people died..
In this case, a series of exceptional rains saturated the soil on mountain slopes discovered by forest fires..
Water erosion also affects all types of human-created infrastructures, such as buildings and monuments. The physical action of water wears away statues and buildings made of stone, and its chemical action causes oxidation wear..
There are several solutions to avoid the effects of water erosion:
Maintaining adequate vegetation cover reduces the impact of rain, as well as runoff. The latter by decreasing the speed of runoff and increasing water infiltration..
Channeling the waters through lined channels controls wild water flows, reducing their erosive impact.
In areas with steep slopes, stepped terraces can be built that neutralize the slope, retaining the soil..
Soil loss due to water entrainment can be reduced or avoided by establishing physical barriers. For example, planting live anti-erosion barriers, such as rows of the vetiver plant (Chrysopogon zizanioides) that has a broad root system that retains soil drag.
Meshes are also installed to support the terrain and concrete covers to protect steep slopes. This is combined with adequate drainage systems to channel the waters.
All those strategies aimed at protecting surfaces from the impact of rain are included here. These range from plastic covers on agricultural soils, to varnishes and special paints on infrastructures.
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