Soil Erosion: River Bank Erosion Control Methods
Preventing soil erosion and providing control methods for river bank is a good practice in the construction industry. Water channels are an excellent resource in cities providing ecological ways to divert water and decrease flood areas. There are several options to prevent and help diminish soil erosion problems along river embankments.
Soil Erosion:Geotextile Roll
Geotextile rolls are non-woven fiber of coconut, bounded together with a polyethylene mesh rope. They usually come in rolls and are rolled out over the surface on the bank, preventing soil erosion on newly graded slopes. Sometimes vegetation can be established over the geotextile and the roots of the vegetation will act as an interlocking agent with the fibers. This is a biodegradable material that will not harm the environment.
This method is usually used on small steams with a consistent water level surface. Important note: Don’t use it on channels that transport large quantity of sediments, because the sediment will be deposited in the geotextile and it will destroy vegetation.
Its advantages are the quickness of its installation, simple installation, biodegradable and relatively low maintenance.
Soil Erosion: Brush Mattress
Is a system of protecting the bank by branches that are anchored to the ground using stakes. This system is ideal capturing sediment in rain events. The drawback of this technique is that the fascines are vulnerable to be washed away during heavy rain.
It is usually applied on perennial steams receiving plenty of sunlight. The system must be placed along the bank and within the soil, so that the mattress can absorb water.
Like the geotextile it can be installed fast, it is simple, is biodegradable and has relatively low maintenance.
Soil Erosion: Gabions
Gabion's mattress are used as bank stabilization where high soil erosion is likely to occur and where the bank is composed of small rocks that will resist the water forces. It is not an aesthetic product, and there is always the possibility of damages in the mesh. It can be filled by rocks, depending on the width of the mattress and also can be filled with concrete rubble.
It can be used almost everywhere but special conditions and precautions must be taken on areas susceptible to rapid erosion and unstable water flow. Special attention must also be considered when designing its footing. There are several cases where the footing has failed, leaving the gabion mattress without its proper support.
Soil Erosion: Rootwad composites
This system consists of interlocking tree material build at the base of the slope. In addition to stabilizing the stream bank by lowering flow velocities, the roots provide complex aquatic habitats for the establishment of aquatic wildlife.
It is a cost effective solution, but it’s highly complex installation process puts some limitations to this process.
Soil Erosion: Tree revetment
This system allows for the bank to be protected anchoring the wood to the bank. This will dissipate the energy of the water flowing through the channel, and reducing its velocity. It is not recommended for areas where high erosion is taken place. Its maintenance is critical and it is one the biggest disadvantages of this system.
Soil Erosion: A-Jacks
A-jacks are interlocking cement stakes that are placed at the foot of the slope. They are effective to increase stability during high intensity storms and scour protection.
This system can be used in high erosion areas, but it is not a biodegradable method. It can be prepared in a wide variety of sizes.