Hydraulically separated or connected with an [[underdrain]], these are often quite small units of 5 - 50 m<sup>2</sup> each. In urban settings the bioretention may be bounded entirely with hardscape, restricting options for [[pretreatment]] and sheet flow. Amenity and safety can be enhanced on sidewalks with a short (~ 45 cm wall) for seating, although the finished grade is usually only slightly lower than surroundings. Where underground space permits, shade [[trees]] are common feature of these facilities, enhancing the streetscape experience and optimizing transpiration. This type of bioretention is often designed offline, with bypass [[overflow]]. | Hydraulically separated or connected with an [[underdrain]], these are often quite small units of 5 - 50 m<sup>2</sup> each. In urban settings the bioretention may be bounded entirely with hardscape, restricting options for [[pretreatment]] and sheet flow. Amenity and safety can be enhanced on sidewalks with a short (~ 45 cm wall) for seating, although the finished grade is usually only slightly lower than surroundings. Where underground space permits, shade [[trees]] are common feature of these facilities, enhancing the streetscape experience and optimizing transpiration. This type of bioretention is often designed offline, with bypass [[overflow]]. |