When installed and used properly silt fence can be a simple and effective Best Management Practice (BMP) to prevent on site erosion from impacting surrounding areas of a work site. Erosion can be caused by wind, water, and other natural agents. If this process is not controlled and contained within an active site, there can be serious implications for the surrounding environment and wildlife. These can include changes in fish migration, loss of sensitive aquatic habitat, and loss of recreational attributes.
Silt fence is commonly placed around the outer perimeter of a site. The effectiveness of silt fence is very much dependent on proper installation, maintenance, and when necessary, supplementation of other erosion control measures. The EPA suggests creating a trench six inches wide and six inches deep to properly hold the fabric in place and provide proper soil compaction at the bottom. Improper trenching can lead to poor soil compaction and thus result in infiltration along the underground portion of the fence. It is also important that the stakes used to hold the fence are placed at proper distances to ensure enough support is in place to hold back sediment. Generally, it is suggested that the distance between stakes should be in the range of 6-8 feet.
Like all BMP’s on a site, maintenance is another key factor that will determine how effective your silt fence may be. Excessive erosion caused by a large rain event or a worker getting too close with a piece of machinery can easily compromise the effectiveness of your silt fence. It is important to regularly inspect all BMP’s on site and determine if they are operating in an effective manner. Necessary action should be taken to either repair or replace any damaged portions to ensure that it is functioning efficiently. It is also important to understand that areas that may be affected by large amounts of erosion such as steep unprotected slopes may need alternative or supplementary control methods to help prevent off site sedimentation.
Silt fence is one way to help protect the surrounding environment and ecosystem from unwanted on-site sediment and contamination. With proper installation of BMPs, regular maintenance, and a good understanding of how erosion effects your site you can be sure that your project is being conducted safely, efficiently, and within compliance of local and federal environmental regulations.