Difference between revisions of "Site considerations"

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!Installation type
 
!Installation type
 
!Depth to high water or bedrock (m)<ref>Minimum depth between the base of the facility and the elevation of the seasonally high water table or top of bedrock</ref>
 
!Depth to high water or bedrock (m)<ref>Minimum depth between the base of the facility and the elevation of the seasonally high water table or top of bedrock</ref>
−
!Typical ratio of impervious <br>drainage area to permeable <br>facility footprint area
+
!Ratio of impervious drainage area to <br>permeable facility footprint area
 
!Native soil infiltration rate (mm/hr)<ref>Infiltration rate estimates based on measurements of hydraulic conductivity under field saturated conditions at the proposed location and depth of the practice</ref>
 
!Native soil infiltration rate (mm/hr)<ref>Infiltration rate estimates based on measurements of hydraulic conductivity under field saturated conditions at the proposed location and depth of the practice</ref>
 
!Head (m)<ref>Vertical distance between the inlet and outlet of the LID practice</ref>
 
!Head (m)<ref>Vertical distance between the inlet and outlet of the LID practice</ref>

Revision as of 18:15, 10 March 2022

Installation type Depth to high water or bedrock (m)[1] Ratio of impervious drainage area to
permeable facility footprint area 		Native soil infiltration rate (mm/hr)[2] Head (m)[3] Space % [4] Slope % [5] Applicable in pollution hotspots [6] Set backs Karst[7] Wellhead protection area[8]
Rain barrels Not applicable Not applicable Not applicable 1 0 NA Yes None Yes None
Cisterns Not applicable Not applicable Not applicable 0 0 0 Yes None Yes None
Roof downspout disconnection Not applicable 4:1 or less Amend 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 applicable (non-infiltrating) 5:1 to 15:1 Underdrain recommended
if < 15 mm/hr		 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 applicable 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 applicable 5:1 Amend 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) 1:1 Underdrain recommended
if < 15 mm/hr		 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 Not applicable 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 Underdrain recommended
if < 15 mm/hr		 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
  1. ↑ Minimum depth between the base of the facility and the elevation of the seasonally high water table or top of bedrock
  2. ↑ Infiltration rate estimates based on measurements of hydraulic conductivity under field saturated conditions at the proposed location and depth of the practice
  3. ↑ Vertical distance between the inlet and outlet of the LID practice
  4. ↑ Percent of open pervious land on the site that is required for the LID practice
  5. ↑ Slope at the LID practice location
  6. ↑ Suitable in pollution hot spots or runoff source areas where land uses or activities have the potential to generate highly contaminated runoff
  7. ↑ Suitability in areas of karst geologic formations
  8. ↑ | Drinking Water Source Protection wellhead protection area time of travel

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.

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