Marginal coverings

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 shore, so that it cannot be eroded and carried away by the current. To do this, the shore is outlined with a slope that allows easy and safe placement of the protective material. Between the margin material and the covering material, a filter is usually placed, which can be geotextile, or natural with layers of stone and sandy materials of decreasing size from the outside towards the margin. The purpose of the filter is to prevent undercutting of the liner, when fine particles of the margin material come out through the gaps, which may be present in the outer layer or liner, designed to resist the high velocities of water flow. The exit or extraction of the particles of the material from the margin is due to the flow towards the river of soil suspended in rainwater, or from the river due to frequent and considerable drops in its water level. Marginal coverings can have the inclination of 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.