Site considerations

Installation type	Depth to high water or bedrock (m)i	Ratio of impervious drainage area to permeable facility footprint area	Native soil infiltration rate (mm/hr)ii	Head (m)iii	Space %iv	Slope %v	Applicable in pollution hotspotsvi	Set backs	Karstvii	Drinking Water Source Protection wellhead protection area time of travel
Rain barrels	Not a constraint	Not applicable	Not a constraint	1	0	NA	Yes	None	Yes	None
Cisterns	Not a constraint	Not applicable	Not a constraint	0	0	0	Yes	None	Yes	None
Roof downspout disconnection	Not a constraint	4:1 or less	Decompaction if < 15 mm/hr	0.5	5 to 20	1 to 5	Yes	Building Foundation	Yes	None
Infiltration trenches or Infiltration chambers	1	5:1 to 20:1	Not a constraint	1 to 2	0 to 1	<15 %	Noix	4m- Building Foundation Underground Utilities, Trees, Drinking Water Wellhead Protection Areas	No	2 year - WHPA-B
Bioretention	1 (infiltrating); Not a constraint (non-infiltrating)	5:1 to 15:1	Decompaction and underdrain recommended if < 15 mm/hr (infiltrating)	1 to 2	5 to 10	0 to 2	No (infiltrating)ix; Yes (non-infiltrating)	4m- Building Foundation Underground Utilities, Trees, Drinking Water Wellhead Protection Areas	No (infiltrating); Yes (non-infiltrating)	2 year - WHPA-B (infiltrating); None (non-infiltrating)
Stormwater planters	Not a constraint	5:1	Not a constraint	1 to 2	2 to 5	0 to 2	No (infiltrating)ix; Yes (non-infiltrating)	Building Foundation, Trees	No (infiltrating); Yes (non-infiltrating)	2 year - WHPA-B (infiltrating); None (non-infiltrating)
Vegetated filter strips	Not a constraint	4:1 or less	Decompaction if < 15 mm/hr	0 to 1	15 to 20	1 to 5	Noix	None	Yes	None
Permeable pavements	1 (infiltrating); Not applicable (non-infiltrating)	0 to 1:1	Underdrain recommended if < 15 mm/hr (infiltrating)	0.5 to 1	0	1 to 5	No (infiltrating)ix; Yes (non-infiltrating)	4m-Underground Utilities Drinking Water Wellhead Protection Areas	No (infiltrating); Yes (non-infiltrating)	2 year - WHPA-B (infiltrating); None (non-infiltrating)
Enhanced swales (featuring check dams)	1	5:1 to 10:1	Decompaction if < 15 mm/hr	1 to 3	5 to 15	0.5 to 6	Noix	4m- Building Foundation Underground Utilities	No	2 year - WHPA-B
Bioswales (Dry swales)	1 (infiltrating); Not applicable (non-infiltrating)	5:1 to 15:1	Decompaction and underdrain recommended if < 15 mm/hr (infiltrating)	1 to 3	5 to 10	0.5 to 6	No (infiltrating)ix; Yes (non-infiltrating)	4m (3m if impermeable liner is used) Building foundation, Underground utilities, Drinking Water Wellhead Protection Areas	No (infiltrating); Yes (non-infiltrating)	2 year - WHPA-B (infiltrating); None (non-infiltrating)
Exfiltration trenches	1	5:1 to 10:1	Not a constraint	1 to 3	0	< 15%	Noix	4m- Building Foundation Underground Utilities, Trees, Drinking Water Wellhead Protection Areas	No	2 year - WHPA-B
Stormwater tree trenches	1	5:1 to 15:1	Underdrain recommended if < 15 mm/hr	1 to 2	5 to 10	0 to 2	No (infiltrating)ix; Yes (non-infiltrating)	4m- Building Foundation Underground Utilities, Drinking Water Wellhead Protection Areas	No (infiltrating); Yes (non-infiltrating)	2 year - WHPA-B

Notes
i Minimum depth between the base of the facility and the elevation of the seasonally high water table or top of bedrock
ii Infiltration rate estimates based on measurements of hydraulic conductivity under field saturated conditions at the proposed location and depth of the practice
iii Vertical distance between the inlet and outlet of the LID practice
iv Percent of open pervious land on the site that is required for the LID practice
v Slope at the LID practice location
vi Suitable in pollution hot spots or runoff source areas where land uses or activities have the potential to generate highly contaminated runoff
vii Suitability in areas of karst geologic formations
viii Drinking Water Source Protection wellhead protection area time of travel
ix May be allowed under special circumstances and if appropriate mitigation actions are taken - please contact your local Source Protection Region (SPR) or Source Protection Area (SPA) for further information. You can find your associated SPR/SPA based on your location here and then visit their site here

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

The total surface area upstream of a point on a stream that drains toward that point. Not to be confused with watershed. The drainage area may include one or more watersheds.

The natural ground material characteristic of or existing by virtue of geographic origin.

The rate at which stormwater percolates into the subsoil measured in inches per hour.

Structures constructed of a non-erosive material, such as suitably sized aggregate, wood, gabions, riprap, or concrete; used to slow runoff water. Can be employed in practices such as bioswales and enhanced grass swales.

Linear bioretention cell designed to convey, treat and attenuate stormwater runoff. The engineered filter media soil mixture and vegetation slows the runoff water to allow sedimentation, filtration through the root zone, evapotranspiration, and infiltration into the underlying native soil.

The upper surface of the zone of saturation, except where the surface is formed by an impermeable body.

Subsurface water level which is defined by the level below which all the spaces in the soil are filled with water; The entire region below the water table is called the saturated zone.

The rate at which stormwater percolates into the subsoil measured in inches per hour.

A parameter that describes the capability of a medium to transmit water.

Low Impact Development. 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.

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.