Bioretention: Performance

STEP are conducting a review of performance for many BMP types throughout 2018. This content will be updated shortly.

Performance of bioretention with internal water storage

Location	Filter media composition	Media depth (cm)	Internal water storage depth (cm)	I/P ratio	Runoff volume reduction (%)	TSS reduction (%)	TN reduction (%)	TP reduction (%)
Montréal	88% sand, 8% fines, 4% OM	180	150	47	97	99	99	99
Virginia	88% sand, 8% fines, 4% OM	180	150	47	97	99	99	99
North Carolina	96% sand, 4% fines	110	88	12	89	58	58	-10
			58		93
		96	72	13	98
			42		100
North Carolina	loamy sand, 3% OM	120	60	20	99	-	-	-
North Carolina	98% sand, 2% fines	90	30	12	90	-	-	-
		90	60	12	98	-	-	-
North Carolina	15% sand, 80% fines, 5% OM	60	45	68	-	-	54	63
		90	75	68	-	-	54	58

For review

• http://ascelibrary.org/doi/10.1061/%28ASCE%29EE.1943-7870.0000876 (pollutants)
• http://ascelibrary.org/doi/abs/10.1061/9780784413883.003 (maturation)
• https://www1.villanova.edu/content/dam/villanova/engineering/vcase/sym-presentations/2011/40_2ayers.pdf (maturation)
• https://www.chijournal.org/C417 (undersized)
• https://www.unh.edu/unhsc/sites/unh.edu.unhsc/files/STONE%20THESIS%20FINAL.pdf (modified biomedia)
• http://www.mdpi.com/2073-4441/5/1/13/htm (cold climate)

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Sustainable Technologies Evaluation Program

Best management practice. State of the art methods or techniques used to manage the quantity and improve the quality of wet weather flow. BMPs include: source, conveyance and end-of-pipe controls.

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

The engineered soil component of bioretention cell or dry swale designs, typically with a high rate of infiltration and designed to retain contaminants through filtration and adsorption to particles.

The ratio of the impervious catchment (drainage) area to the pervious (footprint) area of the receiving BMP.

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.

Total suspended solids

Total nitrogen

Total phosphorus

Mineral particles which are smaller than 2 mm, and which are free of appreciable quantities of clay and silt. Coarse sand usually designates sand grains with particle size between 0.2 and 0.02 mm.

Soil particles with a diameter less than 0.050 mm.

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

Surface runoff from at-grade surfaces, resulting from rain or snowmelt events.

A perforated pipe used to assist the draining of soils.

The downward movement of water through the soil, the downward flow of runoff from the bottom of an infiltration BMP into the soil.

Loss of water from a drainage system as a result of percolation or absorption into the surrounding medium (e.g., the infiltration of water into the native soil through a perforated pipe wall as it is conveyed).

A hard surface area (e.g., road, parking area or rooftop) that prevents or retards the infiltration of water into the soil.

Low impact development is a stormwater management and land development strategy applied at the parcel and subdivision scale that emphasizes conservation and use of on-site natural features integrated with engineered, small scale hydrologic controls to more closely mimic pre-development hydrologic functions.

A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

A biological community, including humans and their natural environment.