Strengthening the coastline

Table of contents:

1.  What could cause coastal erosion?
2.  Coastal protection methods
   1. Capital method
   2. Decorative method
   3. Strengthening with biomats and plants
3. On your own or with professionals?

Those whose buildings are erected near water bodies are concerned about the issue of bank protection of rivers, ponds, lakes, etc. Yes, a view of the beautiful water surface makes the property more attractive and imposes an additional percentage on its cost. But, as we know, water is a powerful element that can sharpen sharp stones and wash away everything in its path. It can provoke subsidence and collapse of the soil — and then the earth can simply go "from under the feet" of the built property. That is why, in order to enjoy the beauty of the water for a long time, living in a house on the shore, it is necessary to take care of strengthening the coastline.

What could cause coastal erosion?

• weak soil base;
• too large an angle of inclination (more than 45 degrees in water and more than 60 degrees on land);
• high pressure at the top of the slope;
• natural disasters (earthquakes, floods, etc.);
• strong currents and waves;
• change in groundwater levels.

There are several effective ways to strengthen the banks. We will tell you which ones in this article.

Coastal protection methods

Capital method

It allows to reduce to zero the probability of damage to the water bank. This is done with the help of the following structures:

1.  Gabions are nets made of galvanized twisted wire, which are installed in the form of boxes filled with stone. The structure is fixed to the ground using anchors. And the boxes are connected to each other with wire. When the boxes are partially filled with stones, "braces" are installed to prevent the gabion walls from diverging. Such structures help strengthen the banks and prevent them from washing away and sinking. Such structures are often found on rivers, bypass canals, ponds in urban areas.

Due to their "mesh" structure, gabions can withstand groundwater and soil "movement". Their service life can exceed 80 years, and their strength becomes higher and higher every year — since the gratings are also filled with vegetation, which strengthens the structures with their root system. They create a continuous coastline, which makes the landscape noble and harmonious. Gabions can also be combined with other methods of strengthening coastlines, such as geogrids and larch piles.


2.  Geogrids
   • crushed stone (if there is a strong current in the reservoir),
   • fertile soil (in a pond with a weak current or with stagnant water),
   • pebbles, marble chips (in a body of water with a weak current or with stagnant water).

These are polymer structures made of strips welded together. The cells are arranged in a checkerboard pattern. They are not afraid of moisture, mold and frost, so they perfectly withstand unpredictable Russian conditions.

Such structures are used on banks of low and medium steepness. The following is used as cell filler:

The most aesthetic option is fertile soil, because over time the geogrid becomes invisible due to the emerging plants. Plus, the structure is additionally strengthened by roots.

To install such a grid, the top layer of soil is first removed, along with plant roots and stones. Then the surface is tamped and leveled.

3.  PVC sheet piles are piles based on PVC and composites, which very quickly and reliably cope with the task of strengthening the banks of reservoirs (suitable for steep banks). A huge advantage of this method is its affordable price. Another advantage is the use of piles twice. The installation of piles is carried out in the form of a solid wall using hydraulic equipment. They are connected using longitudinal protrusions, which are on each pile.

Decorative method

For this method of shore strengthening, natural materials are used: stone and wood. They are not only environmentally friendly, but also cope well with the main task of strengthening the soil.

1.  Wooden piles are made of hard wood, such as oak or larch (the best choice is East Siberian larch). Compared to reinforced concrete piles, wooden piles look more advantageous. The former add grayness to the landscape. But with wooden piles, steep banks immediately acquire an interesting appearance. The only drawback is that the wood darkens over time (depending on the composition of the water). The piles are installed manually or with special equipment. However, it is important to remember that this method of coastal reinforcement is not suitable for places with loose and mobile soil. The service life of piles is about 50 years.
2.  Natural stone — used on long, flat banks. The slope angle should not exceed 20 degrees. The soil must be prepared before laying — otherwise the stones will sink into the soil. Preparation includes laying a supporting base on the bank, such as geotextile, geogrid or geonet. The cells in such material are filled with crushed stone.

A more complex type of work is strengthening the bank with boulders. They are placed tightly to each other. Moreover, each boulder, depending on its shape and color, should be placed in its place — i.e. the work is done manually and requires a lot of physical effort and time. But it is worth it, because the bank turns out to be unique.

Strengthening with biomats and plants

The most labor-intensive way to strengthen the banks is to use biomats and plants. The former are a material made from flax and coconut fibers, and the latter are plants that are specially selected for planting on the banks. Such plants are most often willow, sea buckthorn, amorpha and other shrubs, as well as sedge, reed, manna grass, cattail and other plants growing in water. Their common quality is highly branched roots.

This method is used where the water flow rate in a reservoir is no more than 1 meter per second.

When to carry out coastal protection?

If you decide to create an artificial reservoir on your own property, then the banks should be strengthened at the excavation stage.

Log piles are installed at the stage of creating the reservoir bowl.

On your own or with professionals?

Strengthening the banks is a responsible undertaking that involves considerable expenses. As for your own plots, you can try to strengthen the banks of small artificial reservoirs yourself. The only thing is that no one will give you a guarantee for the work, all responsibility falls on you. If we are talking about large projects, then the work should definitely be entrusted to professionals. This way you can be sure of the quality of the result, because specialists know all the nuances of various coastal strengthening technologies. And before starting work, they will study the following points:

• soil character;
• coastal features (height, angle of inclination, etc.);
• the nature of soil collapse (in water or on the surface of the shore);
• the age of the reservoir and the time period when the collapse began;
• location of the reservoir, landscape of adjacent territories;
• climatic conditions (temperature changes and precipitation).

Changes in the bank line are not only an unaesthetic appearance, but also a number of other consequences: shallowing, destruction of roads and bridges, collapse of buildings, etc. The bank base serves as a support for the entire slope, and when water washes away this base, it is taken for the slope on which there are structures. This is a great danger, so it is extremely important to take care of river bank protection in time. And even if the collapse process has already begun, it can be stopped by strengthening the slope.