Site considerations

Installations type	Depth to high water or bedrock (m)	Typical ratio of Impervious drainage area to Treatment Facility Area	Native soil infiltration rate (mm/hr)	Head (m)	Space %	Slope %	Applicable in pollution hotspots	Set backs	Water table separation	Wellhead protection area
Rain Barrel	Not applicable	5 to 50 m2	Not applicable	1	0	NA	Yes	None	No	None
Cistern	Not applicable	1:1	Not applicable	0	0	0	Yes	None	No	None
Roof downspout disconnection	Not applicable	5 to 100 m2	Amend if < 15 mm/hr	0.5	5 to 20	1 to 5	Yes	Building Foundation	No	None
Soakaway, infiltration trench or chamber	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	Yes	2 yr
Bioretention	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, Trees, Drinking Water Wellhead Protection Areas	Yes	2 yr
Stormwater planters	Not applicable	5:1	Not applicable	1 to 2	2 to 5	0 to 2	Yes	Building Foundation, Trees	No	None
Vegetated filter strip	1	5:1	Amend if < 15 mm/hr	0 to 1	15 to 20	1 to 5	No	None	No	None
Permeable pavement	1	1:1 to 1.2:1	Underdrain recoomended if < 15 mm/hr	0.5 to 1	0	1 to 5	No	4m-Underground Utilities Drinking Water Wellhead Protection Areas	Yes	2 Yr
Enhanced grass swale (has checkdams)	1	5:1 to 10:1	Not applicable	1 to 3	5 to 15	0.5 to 6	No	4m- Building Foundation Underground Utilities	Yes	None
Dry swale (Bioswale)	1	5:1 to 15:1	Underdrain recommended if < 15 mm/hr	1 to 3	5 to 10	0.5 to 6	No	4m (3m if impermeable liner is used)Building foundation, Underground utilities, drinking water wellhead protection areas	Yes	2 Yr
Perforated pipe system	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	Yes	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.

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.

Tank used to store rainwater (typically roof runoff) for later use.

An underground water storage reservoir into which stormwater is directed and allowed to percolate into the underlying native subsoil.

An excavated area lined with geotextile filter cloth and filled with clean granular stone or other void forming material, that receives runoff and allow it to infiltrate into the native soil; can also be referred to as infiltration galleries, French drains, dry wells or soakaway pits.

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

A perforated pipe used to assist the draining of soils.

a gently sloping, densely vegetated areas that treat runoff as sheet flow from adjacent impervious areas. They function by slowing runoff velocity and filtering out suspended sediment and associated pollutants, and by providing some infiltration into underlying soils.

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.

Vegetated open channel, with check dams; designed to convey, treat and attenuate stormwater runoff.

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.

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.