Stopping the Silt, The Increasingly Common Use of Silt Barriers in the United States
Rules and regulations about water contamination have set forth by the government to create environmental policies such as the Clean Water Act and the National Pollution Discharge Elimination System (NPDES). These acts have led to the common use of silt barriers around construction sites and locations where dredging operations take place. These silt barriers are designed to, specifically, ensure that silt and turbidity elements do not contaminate nearby fresh water streams, lakes, ponds, etc. Turbidity is the measure of optical properties, like haziness or cloudiness, of water caused by loose sediment and suspended materials to the naked eye, much like smoke in the air, to determine water quality.
Silt curtains, or turbidity curtains have traditionally been used to control suspended solids or turbidity by creating a silt barrier, made out of a solid or permeable material. Another use for a turbidity barrier might be during some type of oil spill, for example, or any other situation in which material must be restricted from entering fresh bodies of water. This situation calls for a specific type of silt barrier, called a Gunderboom, which has been treated with an absorbent, geotextile material to absorb the oil or hazardous materials.
Although the use of silt barriers is common practice, it is still known as a Best Management Practice because, despite their popularity, they have limited effectiveness because of the simple design or lack of maintenance and care. Controlling turbidity and suspended sediment has become an issue of the past few years because of the increase in dredging projects throughout the world. The United States Environmental Protection Agency has been at the forefront of making some type of silt barrier as a mandated practice amongst most construction companies who may deal with dredging, marina projects, and general construction working near bodies of water.