Site considerations

Installation type	Depth to high water or bedrock (m)	Ratio of impervious drainage area to permeable facility footprint area	Native soil infiltration rate (mm/hr)	Head (m)	Space %	Slope %	Applicable in pollution hotspots	Set backs	Karst	Wellhead protection area
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 %	No	4m- Building Foundation Underground Utilities, Trees, Drinking Water Wellhead Protection Areas	No	2 yr
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); Yes (non-infiltrating)	4m- Building Foundation Underground Utilities, Trees, Drinking Water Wellhead Protection Areas	No (infiltrating); Yes (non-infiltrating)	2 yr (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); Yes (non-infiltrating)	Building Foundation, Trees	No (infiltrating); Yes (non-infiltrating)	2 Yr (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	No	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); Yes (non-infiltrating)	4m-Underground Utilities Drinking Water Wellhead Protection Areas	No (infiltrating); Yes (non-infiltrating)	2 Yr (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	No	4m- Building Foundation Underground Utilities	No	2 Yr
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); 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 Yr (infiltrating); None (non-infiltrating)
Exfiltration trenches	1	5:1 to 10:1	Not a constraint	1 to 3	0	< 15%	No	4m- Building Foundation Underground Utilities, Trees, Drinking Water Wellhead Protection Areas	No	2 Yr
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	4m- Building Foundation Underground Utilities, Drinking Water Wellhead Protection Areas	No	2 yr

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.

A perforated pipe used to assist the draining of soils.

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.