We explain what river erosion is, its causes, phases and ways in which it manifests itself. Also, types of river erosion.
What is river erosion?
River erosion is the wear effect of the land surface that the river has Water from the rivers. In other words, it is the particular way that water modifies the scenery, either flowing over the surface or in underground currents, thus dragging sediments, materials and altering their distribution in the Earth crust.
In fact, water is one of the main erosive factors of our planet, whose action on the earth's crust takes many forms: the tide, the waves, the rain, and also the flow of the rivers. In the latter case, we refer to waterfalls, caves, gorges, meanders, canyons, deltas, estuaries and other alterations of the landscape created in their wake.
Despite its strong erosive impact, this flow of matter Y Energy is essential for the redistribution of different chemical elements and their entry to others biogeological cycles of importance.
Fluvial erosion is due to the energy of water, as well as the transport in it of numerous materials, which impact the earth's crust, modifying it. This can happen in two different ways:
- Superficial erosion. When it occurs by the surface flow of water, it dissolves solid materials and clays, exposing the underlying materials and depositing the dissolved ones in new locations.
- Bottom of riverbed erosion. When it occurs due to the mechanical action of water and the materials that it may drag, such as boulders, blocks, etc., or sand dissolved in it, all of which impacts the surface of the bottom of the riverbed.
And also in three separate phases:
- Mechanical phase. The one with the highest activity, in the higher regions of the river, where the greatest wear occurs due to mechanical action, as a result of the energy of the water and the impact of other materials.
- Intermediate phase. Located further on in the riverbed, it still presents erosive mechanical effects, but already in the middle of other sedimentary processes in which the matter worn out begins to settle.
- Sedimentary phase. Towards the end of the river bed, the mechanical effect of the water is much less intense, but its sedimentary effect is much higher, thus depositing all the eroded material and creating new geological forms.
Types of river erosion
According to its causes and specific forms of action, we can classify river erosion as:
- General erosion. It lowers the river bed in long stretches, affecting it in the long run.
- Erosion by narrowing of the channel. It takes place in segments of the channel in which engineering works were carried out (such as bridges, channeling, etc.) that cause the reduction of the channel, thus increasing the speed of the current and therefore the transport of sediments.
- Erosion due to the curve of the riverbed. Typical, as its name implies, of curvatures in river beds, due to the addition of centripetal force to the energy of the water on the outside of the curve.
- Localized erosion. Also called local erosion, it is due to the action of complex flows, with speeds that require two- or three-dimensional considerations.
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