bioretention

thumb|A bioretention cell, also called a rain garden, in the [[United States. It is designed to treat polluted stormwater runoff from an adjacent parking lot. Plants are in winter dormancy.]]

Bioretention is the process in which contaminants and sedimentation are removed from stormwater runoff. The main objective of the bioretention cell is to attenuate peak runoff as well as to remove stormwater runoff pollutants.