Grass filter strips are low-angle vegetated slopes designed to treat sheet flow runoff from adjacent impervious areas. Filter strips also known as vegetated filter strips and grassed filters function by slowing runoff velocities, filtering out sediment and other pollutants, and providing some infiltration into underlying soils. Because they use sheet flow and not channelized flow, filter strips are often more effective than swales at removing suspended solids and trash from runoff. A filter strip adjacent to this filling station provides room for snow storage and can remove sediment and organics from runoff.
Vegetated Filter Strips
Conservation Choices: Filter Strip
Vegetated Filter Strips From Massachusetts Stormwater Handbook Description Vegetated filter strips, also known as filter strips, grass buffer strips and grass filters, are uniformly graded vegetated surfaces i. Vegetated filter strips typically treat sheet flow or small concentrated flows that can be distributed along the width of the strip using a level spreader. Vegetated filter strips are designed to slow runoff velocities, trap sediment, and promote infiltration, thereby reducing runoff volumes. May be used near cold-water fisheries. Slows runoff velocities and removes sediment. Low maintenance requirements.
Filter strips , also referred to as buffer strips, are small, edge-of-field tracts of vegetated land that are used to reduce the contamination of surface water. They are primarily used in agriculture to control non-point source pollution, however, they may also be used to reduce sediment in storm water runoff from construction sites. In agriculture, they are highly effective in reducing the concentration of nitrogen N and phosphorus P in runoff into surface water   and are also effective in reducing sediment erosion and removing pesticides. The use of filter strips is very common in developed countries  and is required by law in some areas.
Filter strips are uniformly graded, gently sloping, vegetated strips of land that provide opportunities for slow conveyance and commonly infiltration. They are designed to accept runoff as overland sheet flow from upstream development and often lie between a hard-surfaced area and a receiving stream, surface water collection, treatment or disposal system. Filter strips are generally planted with grass or other dense vegetation to treat the runoff through vegetative filtering, sedimentation, and where appropriate infiltration. They are often used as a pre-treatment technique before other sustainable drainage techniques e. Filter strips are best suited to treating runoff from relatively small drainage areas such as roads and highways, roof downspouts, small car parks, and pervious surfaces.