Talk:Soakaways, Infiltration Trenches and Infiltration Chambers Guide

LID Practice		CANADA			United States
Soakaways, Infiltration Trenches and Chambers		CVC+TRCA (Factsheets-2010)	Toronto- 2016	LID-SWM Guide 2010	Massachusets SW BMP-2013	District of Columbia-SWM Guidebook-2010	W. Virginia-SWM design guidance manual-2012	Pennsylvania-City of Philadelphia green St. design manual-2014	Oregon SWM Manual-2014
Setback from Building Foundation (m)		4		4
(Impervious Drainage/Treatment) Area		5:1-20:1, 10:1 recommended		5:1-20:1, 10:1 recommended	CDA < 5 acres	CDA < 2 acres (T), < 5 acres (B)	< 2 acres	Max. load of 10:1 for infiltration systems (not specific to LID type)
Natural Slope (%)		< 15		< 15
A capped vertical standpipe, perforated installed to the bottom of the facility to monitor drainage time (mm)		100-150		100-150
Filter media
Stone Resvoir					1.5" to 3" stone dia., 2" pea gravel above 6" sand below	1.5"-3.5" stone dia. For stone layer, 3" layer of washed river stone, or No. 8 or 89 stone above, 6-8 " of sand below	Stone 1.5"-3.5"		Drain rock 3/4"-2.5 " washed open graded aggregate
Void Space(%)		30-40	30-40	30-40
Granular Material (clear stone)(mm)		50	50	50
Geotextile around the stone reservoir with an overlap at the top (mm)		min. 300	300	min. 300
Bottom Width of Excavations (mm)		600-2400	600-2400	600-2400
Minimum Depth of Excavations under concrete laneway (mm)			3000
Length of Time for Draining after Storm Event (>25mm)		max. 72 hr.		max. 72 hr., 48 hr. recommended
Depth to High Water Table (m)		1		1
Sand Layer Depth (mm)			150-300						Length of Time for Draining after Storm Event (>25mm)
Subdrains Inlet Pipes (mm)			100-200
Overflow is required when the infiltration rate equals			< 15 mm/hr
Facilities receiving road runoff are not located within time of travel wellhead protection areas (years)		2		2

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.

Credit Valley Conservation

Toronto and Region Conservation Authority

Stormwater Management

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

Natural or artificial means of intercepting and removing surface or subsurface water (usually by gravity).

The period between the maximum water level and the minimum level (dry weather or antecedent level).

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.

A broad category of particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates, and available in various particulate size gradations.

Gravel, or crushed stone of various size gradations (i.e., diameter), used in construction; void forming material used as bedding and runoff storage reservoirs and underdrains in stormwater infiltration practices.

Filter fabric that is installed to separate dissimilar soils and provide runoff filtration and contaminant removal benefits while maintaining a suitable rate of flow; may be used to prevent fine-textured soil from entering a coarse granular bed, or to prevent coarse granular from being compressed into underlying finer-textured soils.

An underlying bed filled with aggregate or other void-forming fill material that temporarily stores stormwater before infiltrating into the native soil or being conveyed by an underdrain pipe.

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.

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

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.