Changes

==Planning==

==Planning==

Filter strips are best suited for pretreatment of runoff from roads and parking lots prior to it being treated by other best management practices. They are also an ideal practice within stream or wetland buffer zones. Filter strips can be used as part of a [[treatment train]] approach.  

Filter strips are best suited for pretreatment of runoff from roads and parking lots prior to it being treated by other LID BMPs. They are also an ideal practice within stream or wetland buffer zones. Filter strips can be used as part of a [[treatment train]] approach.  

Filter strips may also be applied at roof leaders, outfalls, or large parking lots if level spreaders are used to create sheet flow. They are often impractical in densely developed urban areas because they consume a large amount of space.

Filter strips may also be applied at roof leaders, outfalls, or large parking lots if level spreaders are used to create sheet flow. They are often impractical in densely developed urban areas because they consume a large amount of space.

Properly functioning filter strips should not pond water on the surface and do not contribute to stream warming. Thus, filter strips are a good stormwater treatment option for cold water streams that support species sensitive to changes in stream temperature.

Properly functioning filter strips should not pond water on the surface and do not contribute to stream warming. Thus, filter strips are a good stormwater treatment option for cold water streams that support species sensitive to changes in stream temperature.

The flow path length across the vegetated filter strip should be at least 5 m to provide substantial water quality benefits <ref name="Barrett2004">Barrett, M., Lantin, A., Austrheim-Smith, S. 2004. Stormwater pollutant removal in roadside vegetated buffer strips. Transportation Research Record. No. 1890, pp. 129-140.</ref>.  

The flow path length across the vegetated filter strip should be at least 5 m to provide substantial water quality benefits <ref name="Barrett2004">Barrett, M., Lantin, A., Austrheim-Smith, S. 2004. Stormwater pollutant removal in roadside vegetated buffer strips. Transportation Research Record. No. 1890, pp. 129-140.</ref>.  

===Topography===

===Topography===

Filter strips are best used to treat runoff from ground-level impervious surfaces that generate sheet flow (e.g., roads and parking areas). The recommended filter strip slope is between 1 - 5 %. Though steeper slopes increase the likelihood of erosion, incorporation of multiple level spreaders in series or terraces can counteract this.

Filter strips are best used to treat runoff from ground-level impervious surfaces that generate sheet flow (e.g., roads and parking areas). The recommended filter strip slope is between 1 - 3 %. Though steeper slopes increase the likelihood of erosion, incorporation of multiple level spreaders in series or terraces can counteract this (see below).

Filter strips are a suitable practice on all soil types. If soils are highly compacted, or of such low fertility that vegetation cannot become established, they should be tilled to a depth of 300 mm and amended with compost to achieve an [[organic matter]] content of 8 to 15% by weight or 30 to 40% by volume.

===Flow Path Length Across Impermeable Surface===

===Flow Path Length Across Impermeable Surface===

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