that is used to manage stormwater runoff to prevent flooding and downstream erosion, and improve water quality in an adjacent river, stream, lake or bay. Sometimes called

A retention basin, (or wet pond, or wet detention basin) it a kind of artificial lake used to manage stormwater runoff (peak flow management) to prevent flooding and downstream erosion, and improve water quality in the local water cycle.

A swale might be considered a small-scale, permaculture version of a retention basin, but the main purpose is groundwater recharge rather than peak flow management.

See also

• Absorption well
• Groundwater recharge