Bioswales

This article is about installations designed to capture and convey surface runoff along a vegetated channel, whilst also promoting infiltration.
For underground conveyance which promotes infiltration, see Exfiltration trenches. For design recommendations on grassed channels, see Enhanced grass swales.

The fundamental components of a swale are:

• Graded channel
• Planting

   Additional components may include:

• Filter media - an engineered soil mix
• Underdrain with clean out and inspection ports
• Impermeable membrane to prevent infiltration to soils below
• Turf reinforcement to prevent scour
• Check dams to facilitate short tern ponding

The portion of water precipitated onto a catchment area, which then flows as surface discharge from the catchment area past a specified point.

Water from rain, snow melt, or irrigation that flows over the land surface.

The slow movement of water into or through a soil or drainage system.

Penetration of water through the ground surface.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.