Compost Filter Sock

Construction filter socks are very easy to install and will provide noticeable results. For compost filter sock detail and a study on its effectiveness, please see "Utilization of Compost Filter Socks," U.S. Dept of Agriculture, Agronomy Technical Note #4.

Benefits of Compost Filter Socks

• Filters runoff before it leaves the construction site
• Acts as an effective perimeter for the work area
• Unlike silt fence, does not require trenching for installation
• Reliable erosion and sediment control
• Can be seeded for permanent erosion control
• Complies with green building programs
• Can be easily adapted to fit a variety of filtration applications
• If installed permanently, there are no disposal costs
• Can be installed on paved surfaces, compacted ground, and frozen soil
• Minimal impact to the habitat, as no roots are disturbed

For stormwater filtration and use in construction, compost filter socks consist of UV stabilized polypropylene netting, filled with a blend of wood shavings and compost for filtration. Construction filter socks are available in 8, 12, and 18" diameter sizes to meet the stormwater mitigation requirements of your site.

Compost filter socks are faster and easier to install than the commonly used black silt fencing, and they provide an affordable environmentally friendly alternative. Compost socks provide superior filtration for stormwater and can even be left on site permanently. Construction filter socks efficiently and naturally filter out sediment and many common pollutants, keeping your jobsite in compliance with federal stormwater regulations. Since they do not require trenching, erosion control socks can be used near paving, on compacted soil, and even on frozen ground.

Compost socks also often used for erosion control, or for reducing stormwater velocity. Per a national water quality assessment, 75% of the United States' population is living within 10 miles of an impaired water body. Additionally, the leading pollutant in surface water is sediment from stormwater runoff. It is easy to see why efforts to satisfy federal clean water regulations have never been more important for municipalities.

Some common applications for compost filter socks include:

• Perimeter sediment control
• Reduction of suspended solids and turbidity
• Check dam functionality for reducing soil erosion in swales and ditches
• Curb inlet protection
• Reduces the concentration of common pollutants in stormwater
• Reduces stormwater flow velocity
• Reduces erosion and habitat destruction
• If installed permanently, there are no disposal costs

Place compost socks on bare soil, on erosion control blankets, on paved surfaces, or even on grass. However, the surface should be as smooth as possible. (If placing on grass, mow the installation area before seating the compost filter sock.) If the application area has not been prepared properly, water may pass beneath the erosion control sock and render it ineffective.

The installation instructions and compost filter sock detail will vary depending upon the intended application. For all applications, no trenching is required. For use on sites with sheetflow conditions, install the erosion control socks and stake them at 10' centers. If installed in locations with concentrated flow conditions, the compost socks should be staked at 5' centers. Hardwood stakes are generally sufficient for most site conditions. For securing compost socks in severe runoff conditions or sites with loose soil, metal stakes are preferred.

For Sediment Control - If using the construction filter sock for sediment control and filtration, be sure to consider site contours. Place the compost sock perpendicular to the stormwater flow. The construction filter sock must be placed at least 5 feet from the base of a slope for proper performance. Make sure the compost sock's ends are pointed upslope to ensure that untreated stormwater stays within the erosion control sock's confinement area.

For Check Dams - For use as a check dam in swales or ditches, compost filter socks can be placed either straight across the ditch or swale, in a V shape, or in an inverted V shape. The erosion control sock should be at least 6" below the bank. To further reduce stormwater flow, place check dams closer together in a series. Slower water velocity results in less erosion and greater filtration.

For Slope Interruption - To interrupt the stormwater flow and reduce velocity, place the erosion control socks horizontally, always with the ends of the socks pointing upslope.

For Curb Inlet Protection - For protecting curb inlets, the compost filter sock needs to be fully inside the sump and at ground level. The filter sock should not be higher than the inlet opening.

Note: Compost filter socks can be stacked to increase the filtering capacity. They also can be seeded (or purchased pre-seeded) for permanent installation.