Turbidity curtains, also referred to as silt curtains, offer a means to keep suspended particles from vacating the immediate area in a body of water. The curtains hang from floats down into the water and impede the flow of the turbidity or silt. Over time, the suspended sediment settles back to the bottom. These floating curtains can be made from solid fabrics that impede all flow of water, or built using a geotextile mesh fabric that allows water to flow through while still blocking the silt or other particles from escaping.
One application for turbidity curtains is to contain runoff from storm drains or pump station discharge points. These are typically exit points for storm drain systems that provide drainage from developed urban areas to prevent or minimize flooding. Because the water is collected from public streets and other areas, the water is prone to washing away trash, dirt, and other debris. Instead of simply dumping this water into waterways, the systems may run the water through filtering processes to remove garbage and larger debris. However, these filters may not capture all of the materials suspended in the water.
By creating a barrier using a turbidity curtain between the drain exit point and the body of water, much of what passes out of the storm drain system other than water can be retained. The floating curtain system allows any suspended sediment to settle to the bottom instead of washing downstream. Should there also be a concern of oil, fuel, or other hydrocarbons also being discharged, floating sorbent boom can also be used in conjunction with the turbidity curtain to capture and retain any slick that may form as it comes in contact with the sorbent boom.