Marginal coatings

They consist of natural material that is transplanted, or artificial, for example, in the form of gabions, which is placed directly on the soil of the bank, so that it cannot be eroded and carried away by the current. To do this, the bank is profiled with a slope that allows the easy and safe placement of the protection material. Between the bank material and the covering material, a filter is usually placed, which can be geotextile, or natural with layers of stony and sandy materials of decreasing size from the outside towards the bank. The purpose of the filter is to prevent the undermining of the covering, when the fine particles of the bank material come out through the gaps that the outer layer or covering may have, designed to withstand the high speeds of the water flow. The exit or extraction of the particles of the bank material is due to the flow towards the river of soil suspended in rainwater, or of the river due to frequent and considerable drops in its water level. Marginal coverings can have the same inclination as the bank slope when they rest directly on it. They are also built vertically, forming walls, especially in the sections where rivers border or cross cities and towns.