Bioretention: Parking lots

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On commercial, industrial and multi-unit developments, a popular choice is to integrate bioretention into parking lot landscaped areas. These distributed cells typically accept sheet flow through multiple curb cuts, have shallow depression storage ≤ 100 mm, and a total area of 5 -200 m². Although many parking lot schemes include long linear bioretention cells (≥ 0.6 m wide), infiltration is optimized by having a level grade and a level base, unlike a bioswale.

Winter maintenance

Salt can be damaging to the planting in parking lot bioretention. To help minimize this, bioretention practices adjacent to parking areas should always have an underdrain and salt use be reduced through good design and planning of the parking lot.

Gallery

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  Parking lot bioretention with surface ponding well in foreground, Kortright Centre, Vaughan, ON. Read about the performance of this practice in the technical brief.

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  Parking lot bioretention sharing underground reservoir with adjacent permeable paving, Edwards Gardens, Toronto, ON. Read a case study about it here.

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  Parking lot bioretention with decorative stone for erosion control, and perforated pipe access standpipe in foreground, Earth Rangers Centre, Vaughan, ON. Read about the performance of this practice in the technical brief.

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  The sunken curb holds the edge of the asphalt pavement and lets water freely flow to the bioretention cell beside the 7sigma parking lot in Minneapolis, MN (USA)
  Photo credit:Brian Ash

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  Bioretention cells on Elm Drive, Mississauga, ON, with vertical sides and hardscape perimeter receive road runoff via leader pipes from road catch basin inlets. Read about the stormwater system at this site in the performance assessment report.

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  The grade and lack of curb allow for sheet-flow runoff into this bioretention facility. Lakeside Park, Mississauga, ON

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  Bioretention cell receiving road and walkway runoff in a high density development setting.

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  Bioretention bump out in a dense urban setting receiving runoff via side inlet catch basin and curb openings on the walkway side of the installation.

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  Fairford Parkette featuring a bioretention cell retrofitted into a roadway in downtown Toronto, ON. Read a case study about it here.

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  Bioretention cell located in Waterfront Park in Ajax, ON.

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  Parking lot bioretention cell at IMAX corporate headquarters in Mississauga, ON. Read about the IMAX stormwater system in the performance assessment report

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  A curb extension bioretention cell in action during a major rain event.

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  Bioretention cell receiving road runoff in the Wychwood neighbourhood of Brampton, ON. The nearby catch basin conveys overflows during major rain events. Read about the stormwater system in this community in the performance assessment report.

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  Kortright Centre parking lot bioretention cell in action during a rain event, Vaughan, ON.

See Also

• Bioretention: Streetscapes
• Stormwater planters
• Rain gardens

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• Trees
• Perennials
• Inlets
• Forebays
• Overflow
• Mulch
• Filter media
• Choking layer
• Reservoir
• underdrain

A technique for incorporating shallow depressed areas into urban landscaped areas for storing and infiltrating runoff. Depression storage areas are small and have limited capacity and limited duration of retention in order to address property owner concerns relating to insects, damage to structures and inconvenience of ponded water on their property.

A shallow excavated surface depression containing prepared filter media, mulch, and planted with selected vegetation.

An alternative practice to traditional impervious pavement, prevents the generation of runoff by allowing precipitation falling on the surface to infiltrate through the surface course into an underlying stone reservoir and, where suitable conditions exist, into the native soil.

Includes the protection of soil from dislocation by water, wind or other agents.

A mixture of mineral aggregates bound with bituminous materials, used in the construction and maintenance of paved surfaces.

A shallow excavated surface depression containing prepared filter media, mulch, and planted with selected vegetation.

The portion of water precipitated onto a catchment area, which then flows as surface discharge from the catchment area past a specified point.

Water from rain, snow melt, or irrigation that flows over the land surface.

Ground depression acting as a flow control and water treatment structure, that is normally dry.