Swale (landform)

[2] Bioswales are swales that involve the inclusion of plants or vegetation in their construction, specifically.

[3] The use of swales has been popularized as a rainwater-harvesting and soil-conservation strategy by Bill Mollison, David Holmgren, and other advocates of permaculture.

This archetypal form of swale is a dug-out, sloped, often grassed or reeded "ditch" or "lull" in the landform.

One option involves piling the soil onto a new bank on the still lower slope, in which case a bund or berm is formed, mitigating the natural (and often hardscape-increased) risks to slopes below and to any linked watercourse from flash flooding.

In arid and seasonally dry places, vegetation (existing or planted) in the swale benefits heavily from the concentration of runoff.