Controlling sediment at source: an evaluation of erosion control geotextiles

The detrimental environmental impacts of soil erosion and sediment production are well documented, and this has increased pressure on landscape architects, construction engineers and site contractors to ensure that 'best management practice' is used to prevent sediment movement from vulnerable slopes. European Union policy in this area aims to minimize soil erosion losses in order to protect water, land and soil resources. Geotextiles (or erosion control mats and blankets), made from natural or synthetic fibres, can be installed on bare soil slopes, to protect against the erosive forces of wind, surface runoff, rainfall and waves. However, the extensive range of products available and yet limited performance data on erosion control geotextiles can make the selection process difficult for end users. This paper presents one method to evaluate the effectiveness or ability of geotextiles in controlling soil erosion. Taking a geomorphological approach, the sub-processes of erosion (rainsplash and overland flow) are simulated separately to assess the ways in which different geotextile products interact with, and thus influence, the processes of soil detachment and transport. The results show that some products are successful at controlling rainsplash detachment and transport, but are less efficient at controlling the erosivity of overland flow. Other products have the opposite effect. This level of analysis helps identify effective products, as well as highlighting the physical characteristics required of a geotextile to maximize its effect on limiting detachment and transport of soil particles. Copyright (C) 2006 John Wiley & Sons, Ltd.