Swale (geographical feature)

A swale is a low tract of land, especially when moist or marshy. The term can refer to a natural landscape feature or a human-created one. When created by humans, this open drain system is designed to manage water runoff. ("See bioswale.")

The term swale has been popularized as a rainwater harvesting and soil conservation strategy by Bill Mollison and advocates of permaculture. Swales as used in permaculture are designed to slow and capture runoff by spreading it horizontally across the landscape (along an elevation contour line), facilitating its infiltration into the soil. This type of swale is created by digging a ditch on contour and piling the dirt on the downstream side of the ditch to create a berm. In arid climates, vegetation (existing or planted) along the swale can benefit from the concentration of runoff.

Alternatively, the term swale may refer to a dry creek, a very shallow ditch dug between building lots to direct overland flow to storm sewer inlets.

"Swaleing" [ [http://www.churchofdeepecology.org/perm06.pdf Designing For Permaculture] from Church of Deep Ecology] is the burning of dry vegetation on such land, as practiced on Dartmoor, for example.

ee also

*Bioswale
*Gutter
*Keyline design
*Rain garden
*Surface runoff
*Stormwater

References

External links

* [http://cfpub.epa.gov/npdes/stormwater/menuofbmps/index.cfm?action=browse&Rbutton=detail&bmp=75 Fact Sheet: Grassed Swales] from US Environmental Protection Agency
* [http://www.fhwa.dot.gov/environment/ultraurb/3fs10.htm Fact Sheet: Dry and Wet Vegetated Swales] from Federal Highway Administration