Erosion Control

The two most important agents of soil erosion are wind and water. Large tracts of land are made unusable or less productive by these two. Erosion control has always been a problem and most people would accept that the problem grows every year. For a long time, very little was done except when it was a clear case of urgent needs such as flooding or landslides. To a large degree, the problem is still more ignored than acted on. It used to be tackled on an adhoc basis using whatever was available including traditional materials like wood, rocks, cement, rubber and gabions but also rare use of coir matting and jute hessian.

It is argued by many that the use of erosion control measures and materials is cost affective but no studies have been published that have undertaken a cost benefit analysis. Therefore, the argument on erosion control is still largely an article of faith. There may be studies that have not been published but IECA is trying to undertake the analysis. The argument for erosion control, therefore, largely still rests on public opinion and that of professionals. With the spread of environmental consciousness more people become convinced of the common sense argument for action.

Use of materials is determined, of course, by the nature of the problem and choice of materials divides up into the time period that they are expected to last. Choice of materials depends on what is available and on what people become accustomed to. At one extreme are permanent works made from hard materials and expected to last a long time. Cement and cement works, rocks, steel cages to hold the rocks, timber, steel nets and even rubber tyres fall into this category.

At the other extreme are Geotextiles which are an important part of the erosion control materials market. They too are divided by the expected longitude of their life as well as other characteristics. Advances in technology and consequently materials development has allowed an increasing role for geotextiles with different plastic structures that have been developed using large research and development budgets. But there was also a need for the characteristics of natural materials. In the way of an illustration, blankets can be made of straw, wood, waste fibres and have the advantage of also being cheap. A basic distinction is between wovens and non-wovens and standard technology and machinery to produce both.

The use of geotextiles, whether they be synthetic or natural was being developed from the 1960s. The major effort was to come from synthetic fabric manufacturers looking for new market applications for a fast growing production. A number of textile manufacturers in Europe and in USA led the way. In the 1970s German exporters promoted use of geo-jute for the emerging erosion control industry but the plastic industry was also looking for end use applications that they could cater for and targeted sacking, carpet backing and geotextiles.

The plastics industry took action in the above areas where both, natural and synthetic textiles were applicable. The two global geosynthetics industry leaders today are Propex from USA and Tencate from Europe, the product of consolidation in the industry, but there are many others of substantial scale. Both come from a polymers background. Propex has diversified into carpet backing cloth (CBC), geotextiles and concrete reinforcement. Tencate have diversified into geotextiles, artificial turf, protective clothing and other technical fabrics. The two have a turnover in hundreds of millions of dollars per annum. They both emphasise product development and a balance between volume and product differentiation. Between the two of them, they account for one third of all geosynthetics and 57% of USA and Europe sales of geosynthetics combined.