Erosion Control


Gabions can be used in a variety of contexts. Image by Acanfora at en.wikipedia

South Africa is a country challenged by so much to do if it wants to provide sufficiently for all its citizens. In a sense, the country is lucky to have an abundance of natural resources because it allows them to use these in order to meet some of needs of South Africans. However, eco-friendly solutions have to be introduced to counter the effects of nature’s and man’s destructive habits.

Soil erosion in South Africa is a very serious problem. Approximately 25% of South Africa’s land is extremely degraded and 90% of the land is sub-humid, semi arid, or arid according to the UN Environment Programme. This will eventually lead to desertification unless the country does something significant. Desertification will affect rural life, farmers, and increase poverty and food supply. Soil erosion has not been called “the cancer of agriculture” for nothing. It can very devastating and fatal. For deeper insight on the subject, perhaps check out books available at a reputable online bookstore.

One of the eco-friendly solutions to soil erosion is the gabion. This is a cage, basket, or box that is filled with rocks, geotextile, soil, sand, or even concrete to prevent soil erosion. Gabions are used to build walls along river banks to reduce the flow of water into the soil. It is also used in mining to keep walls the mines from caving in thereby protecting miners.

The gabions are tied together with wire and arranged in an angle instead of stacked upright and vertical. In some situations, the gabions are position in odd angles so the wall can conform to the flow of water and ground movement. Over time, the gabion blocks strengthen because silt enters into the structure and adds reinforcement.

Gabions are not just used for houses and riverbanks; they are also seen in roads and cliffs to prevent landslides or rocks from falling on unsuspecting people or vehicles.

The weak link in the gabion is the wire used to hold the gabion together. Today, galvanized steel wire is the most commonly used wire for gabions although some companies selling gabions have opted to use stainless steel wires. If bought from a reputable company, gabions can last for at least 50 years.

Other designs in the gabion are the mattress and the trapion. The mattress gabion is used for short heights and wide lengths. This means it is more commonly seen in water sources and not used to make eco-friendly houses. The trapion is a design using the trapezoid (a quadrilateral) where the base is longer than the top. It is a term that belongs to one company who created the design and registered it as their trademark.

Gabions as eco-friendly solutions are being seen as one way South Africa can increase its arable land. Currently, only 4% of the country is seen as having the potential to be highly arable. The fear among experts is that this will decrease because of soil erosion and urbanization.

Several companies have begun to work feverishly to protect the soil especially the top soil. Since it takes 100 years for 1 cm of soil to be formed and up to 12,000 years for soil to become productive, gabions have been utilized so unprotected soil will not be washed away by rain, flood, or water sources.

According to Leham Lindeque who is the president of International Erosion Control Association of South Africa (IECA-SA), widespread overuse of soil is also a major cause for soil erosion. After the Apartheid, he says many South Africans began to use the land indiscriminately for their livestock, farming, and living. Unfortunately, the government is not doing enough to help farmers fight soil erosion. They have the LandCare Programme but with its limited budget, it will not be sufficient to curb the problem of soil erosion.