Difference between revisions of "Stormwater planters"

From LID SWM Planning and Design Guide
Jump to navigation Jump to search
Line 94: Line 94:
  
 
<imagemap>
 
<imagemap>
−
Image:Stormwater planter.png|thumb|450 px|Stormwater planter with impermeable membrane liner receiving roof and sidewalk runoff via trench drain.  <span style="color:red">''A note: The following is an "image map", feel free to explore the image with your cursor and click on highlighted labels that appear to take you to corresponding pages on the Wiki.''</span>
+
Image:Stormwater Planter Updated.png|thumb|450 px|Stormwater planter with impermeable membrane liner receiving roof and sidewalk runoff via trench drain.  <span style="color:red">''A note: The following is an "image map", feel free to explore the image with your cursor and click on highlighted labels that appear to take you to corresponding pages on the Wiki.''</span>
−
circle 390 1042 75 [[Shrubs: List|Shrubs]]
+
rect 705 411 1013 1092 [[Shrubs: List|Shrubs]]
−
rect 469 507 316 169 [[Shrubs: List|Shrubs]]
+
rect 753 2109 1028 2562 [[Shrubs: List|Shrubs]]
−
circle 252 1055 63 [[Perennials: List| Perennials]]
+
rect 465 363 694 1149 [[Perennials: List| Perennials]]
−
rect 220 167 312 506 [[Perennials: List| Perennials]]
+
rect 275 410 463 1342 [[Graminoids:_List| Grasses]]
−
rect 462 1070 528 1118 [[Graminoids:_List| Grasses]]
+
rect 467 1149 1169 1350 [[Graminoids:_List| Grasses]]
−
poly 532 522 532 607 132 610 132 58 532 58 530 386 474 386 472 163 222 158 194 132 168 138 156 170 180 199 208 202 214 522 532 519 532 606 [[Graminoids:_List| Grasses]]
+
rect 1017 844 1163 130 [[Graminoids:_List| Grasses]]
−
rect 480 400 534 517 [[Forebays]]
+
rect 281 132 1019 346 [[Graminoids:_List| Grasses]]
−
circle 190 169 26 [[Overflow]]
+
rect 450 408 373 339 [[Overflow]]
−
rect 152 1166 340 1189 [[mulch]]
+
rect 1015 862 1049 1139 [[Mulch]]
−
rect 65 1164 538 1190 [[mulch]]
+
rect 284 2566 1142 2622 [[Mulch]]
−
rect 341 1104 363 1303 [[Overflow]]
+
rect 1053 870 1161 1146 [[Forebays]]
−
rect 152 1191 339 1301 [[Biomedia]]
+
rect 692 2881 761 2952 [[Underdrain]]
−
rect 366 1194 541 1302 [[Biomedia]]
+
rect 699 2416 752 2883 [[Overflow]]
−
poly 162 1305 533 1307 352 1343 [[Underdrains]]
+
rect 266 2329 448 2566 [[Graminoids:_List| Grasses]]
−
rect 229 1162 151 1079 [[Grasses]]
+
rect 400 2183 703 2566 [[Perennials: List| Perennials]]
−
rect 227 1019 340 1164 [[Perennials]]
+
rect 1035 2376 1104 2571 [[Graminoids:_List| Grasses]]
−
rect 369 972 483 1162 [[Shrubs]]
+
rect 281 2622 1143 2876 [[Biomedia|Filter Media]]
−
poly 139 1158 149 1155 151 1303 352 1343 542 1305 541 1165 550 1161 553 1311 354 1355 139 1311 [[Liner]]
+
rect 473 2878 953 2929 [[Choker layer|Choker Layer]]
 +
poly 602 2925 290 2876 261 2557 264 2887 735 2977 1151 2889 1145 2869 849 2928 728 2952 [[Liner]]
 +
rect 1140 2557 1165 2887 [[Liner]]
 
</imagemap>
 
</imagemap>
−
 
  
 
Over underground infrastructure, soils prone to subsidence, or on sites considered to be pollution hot spots, it may be necessary to prevent all [[infiltration]]. Stormwater planters are "filtration-only" BMPs, similar to bioretention cells, that can be squeezed into tight urban spaces, adjacent to buildings and within the usual setbacks required for infiltrating facilities. Stormwater planters can also be used as a means of providing building-integrated LID by capturing a portion of the rainwater from the rooftop.  
 
Over underground infrastructure, soils prone to subsidence, or on sites considered to be pollution hot spots, it may be necessary to prevent all [[infiltration]]. Stormwater planters are "filtration-only" BMPs, similar to bioretention cells, that can be squeezed into tight urban spaces, adjacent to buildings and within the usual setbacks required for infiltrating facilities. Stormwater planters can also be used as a means of providing building-integrated LID by capturing a portion of the rainwater from the rooftop.  

Revision as of 20:48, 4 March 2022

Underdrain Access StructureUnderdrain Access StructureUnderdrainMulchMulchMulchMulchMulchMulchErosion Control - StoneErosion Control - StoneCurb CutCurb CutTreeVegetationVegetationOverflow OutletTreeVegetationPonding DepthMulchMulchOverflow Outlet PipeOverflow OutletFilter MediaFilter MediaFilter MediaChoker LayerChoker LayerChoker LayerClear Stone / AggregateClear Stone / AggregateClear Stone / AggregateCompacted Native SoilImpermeable LinerImpermeable LinerImpermeable Liner
Stormwater planter or no infiltration bioretention cell draining a parking lot. This design variation includes an impermeable liner, an underdrain and surface overflow pipes to allow excess water to leave the practice. A note: The following is an "image map", feel free to explore the image with your cursor and click on highlighted labels that appear to take you to corresponding pages on the Wiki.
An above ground stormwater planter with downspout and overflow illustrated.

Over underground infrastructure, soils prone to subsidence, or on sites considered to be pollution hot spots, it may be necessary to prevent all infiltration. Stormwater planters are "no infiltration" or "filtration-only" BMPs, similar to bioretention cells, that can be squeezed into tight urban spaces, adjacent to buildings and within the usual setbacks required for infiltrating facilities. Stormwater planters can also be used as a means of providing building-integrated LID by capturing a portion of the rainwater from the rooftop. This type of cell can be constructed above grade in any waterproof and structurally sound container, e.g. in cast concrete or a metal tank.

Overview[edit]

Stormwater planters are an ideal technology for:

  • Sites which cannot infiltrate water owing to contaminated soils or shallow bedrock,
  • Zero-lot-line developments such as condos or dense urban infill.

Take a look at the downloadable Bioretention Factsheet below for a .pdf overview of this LID Best Management Practice:

Bioretention.png


The fundamental components of a stormwater planter are:


The design may benefit from:





Planning Considerations[edit]

Stormwater planters may be integrated into the landscape similarly to bioretention practices. See bioretention planning.

Additional site opportunities[edit]

As they do not require connection to the earth for infiltration purposes, stormwater planters can also be used in elevated locations. They are sometimes used in retrofit applications on otherwise impermeable surface, as raised beds or planters surrounding buildings. They can be employed to capture runoff from roof drains or downspouts or even upon terraces or vertical surfaces of buildings.

Design[edit]

A flow-through planter comprises a ponding zone, mulch layer, filter media for planting, and a supporting gravel drainage layer

This article is specific to flow-through stormwater planters, vegetated systems that do not infiltrate water to the native soil.
If you are designing a planted system which does infiltrate water, see advice on Bioretention: Sizing.

The dimensions of a stormwater planter are largely predetermined according to the function of the component. As they do not contain a storage reservoir the planters rely more upon careful selection of materials. Both the saturated hydraulic conductivity of the filter media and the number and size of perforations of the underdrain pipe play critical roles for flow control. Options for maintaining separation between filter media and clear stone aggregate surrounding the perforated pipe include a 100 mm deep choker layer or sheet of geotextile filter fabric.

Component Recommended depth (with underdrain pipe) Typical porosity (n)
Ponding (dp) 150 to 450 mm 1
Mulch 75 ± 25 mm
  • 0.7 for wood based
  • 0.4 for stone
Filter media (dm)
  • 300 mm to support turf grass (and accept only rainwater/roof runoff)
  • 600 mm to support shrubs, flowering perennials and decorative grasses
  • 1000 mm to support trees
  • 0.4 for sandier Blend A - Drainage rate priority;
  • 0.35 for more loamy Blend B - Water quality treatment priority
Choker layer 100 mm 0.4
Perforated pipe diameter 150 to 200 mm 0.4
Clear stone aggregate layer below perforated pipe 50 mm (although commonly omitted altogether). 0.4

Filter media[edit]

See Bioretention: Filter media

Underdrain[edit]

Stormwater planters differ from full and/or partial infiltration bioretention practices in that the storage function is provided only by the water retention capacity of the filter media. As such, there is no storage reservoir and the only purpose to the aggregate layer is to drain water to the perforated pipe. For this, a medium aggregate as described in choker layer is recommended as it negates the need for a separating layer to the filter media. Design details can be found here Underdrains for non-exfiltrationg practices.

Planting[edit]

  • Planters must be designed in a way that insulates the soil through freezing temperatures, or plant species that can survive the winter season in raised planters must be used.
  • Stormwater planters routinely capture only rainwater flowing from adjacent rooftops. This means that salt may be less of a concern than in Bioretention: Parking lots or Bioretention: Streetscapes.
  • The plant lists are still a good place to start when selecting species for LID in Ontario.
  • A more formal aesthetic for the planting design is appropriate for the urban hardscape setting.
ShrubsShrubsPerennialsGrassesGrassesGrassesGrassesOverflowMulchMulchForebaysUnderdrainOverflowGrassesPerennialsGrassesFilter MediaChoker LayerLinerLiner
Stormwater planter with impermeable membrane liner receiving roof and sidewalk runoff via trench drain. A note: The following is an "image map", feel free to explore the image with your cursor and click on highlighted labels that appear to take you to corresponding pages on the Wiki.

Over underground infrastructure, soils prone to subsidence, or on sites considered to be pollution hot spots, it may be necessary to prevent all infiltration. Stormwater planters are "filtration-only" BMPs, similar to bioretention cells, that can be squeezed into tight urban spaces, adjacent to buildings and within the usual setbacks required for infiltrating facilities. Stormwater planters can also be used as a means of providing building-integrated LID by capturing a portion of the rainwater from the rooftop. This type of cell can be constructed above grade in any waterproof and structurally sound container, e.g. in cast concrete or a metal tank.


Liners[edit]

An impermeable liner is incorporated into non-infiltrating practices such as stormwater planters, and may be applied in permeable pavements installations where separation from the native soils and groundwater is required.

  • Waterproof containment can be created using concrete or a plastic membrane/liner (HDPE or EPDM are common materials).
    • When the membrane is being used directly in the ground, punctures from stones can be prevented by compacting a layer sand (30 - 50 mm) over the soil prior to installing the membrane.
    • Alternatively, a manufactured cushion fabric (geotextile) can be employed for this purpose.
    • The top surface of the membrane must also be protected from stone and gravel being used for inside the BMP. Again, sand or a cushion fabric may be used.
  • When a pipe is used to provide drainage from the practice to an outlet structure or storm sewer, a 'pipe boot' or flange should be sealed to both the pipe and the liner to prevent leaks.

Filter bed surface[edit]

As stormwater planters are often quite small and receive very rapid flow, both a level spreader and the use of mulch and stone to dissipate energy from concentrated inflow are strongly recommended.

Gallery[edit]

  • Stormwater planters are ideal for situating alongside buildings to capture rainwater from roof runoff. LSRCA headquarters, 2017.

  • Stormwater planter, treating downspout runoff, at Waterview Rec Center, Philidelphia
    Photo credit: PWD

  • Rain garden, Illick Hall, SUNY College of Environmental Science and Forestry, Syracuse, NY
    Photo credit: DASonnenfeld

Performance[edit]

Hydrology[edit]

[1] [2]

Water quality[edit]

[3] [4] [5]

See Also[edit]

Proprietary links[edit]

A number of precast modules exist to contain treatment media. As many of these systems are enclosed water balance calculations may be erroneous where evapotranspiration is constrained. In our effort to make this guide as functional as possible, we have decided to include proprietary systems and links to manufacturers websites.
Inclusion of such links does not constitute endorsement by the Sustainable Technologies Evaluation Program.
Lists are ordered alphabetically; link updates are welcomed using the form below.

  1. ↑ Davis, Allen P., Robert G. Traver, William F. Hunt, Ryan Lee, Robert A. Brown, and Jennifer M. Olszewski. “Hydrologic Performance of Bioretention Storm-Water Control Measures.” Journal of Hydrologic Engineering 17, no. 5 (May 2012): 604–14. doi:10.1061/(ASCE)HE.1943-5584.0000467.
  2. ↑ Yeakley, J.A., and K.K. Norton. “Performance Assessment of Three Types of Rainwater Detention Structures for an Urban Development in Wilsonville, Oregon, USA,” 70. Portland, 2009.
  3. ↑ Macnamara, J.; Derry, C. Pollution Removal Performance of Laboratory Simulations of Sydney’s Street Stormwater Biofilters. Water 2017, 9, 907.;doi:10.3390/w9110907
  4. ↑ Lucke, T., & Nichols, P. W. B. (2015). The pollution removal and stormwater reduction performance of street-side bioretention basins after ten years in operation. Science of The Total Environment, 536, 784–792. https://doi.org/10.1016/J.SCITOTENV.2015.07.142
  5. ↑ Macnamara, J.; Derry, C. Pollution Removal Performance of Laboratory Simulations of Sydney’s Street Stormwater Biofilters. Water 2017, 9, 907. doi:10.3390/w9110907

A vegetated practice that collects and treats stormwater through sedimentation and filtration. Contributions to water cycle/water balance are through evapotranspiration only; no infiltration.

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 vegetated practice that collects and treats stormwater through sedimentation and filtration. Contributions to water cycle/water balance are through evapotranspiration only; no infiltration.

The slow movement of water into or through a soil or drainage system.

Penetration of water through the ground surface.

The technique of removing pollutants from runoff as it infiltrates through the soil.

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.

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

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.

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.

a top dressing over vegetation beds that provides suppresses weeds and helps retain soil moisture in bioretention cells, stormwater planters and dry swales.

The engineered soil component of bioretention cell or dry swale designs, typically with a high rate of infiltration and designed to retain contaminants through filtration and adsorption to particles.

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

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.

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

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.

The porosity (n) of a mixture is the ratio of the volume of void-space to the total or bulk volume of the mixture. It is closely related to the concept of void ratio (e) where void ratio is the ratio of the volume of void-space to the volume of solids. n = Volume of voids/Total volume of mixture = e/(1+e)

The engineered soil component of bioretention cell or dry swale designs, typically with a high rate of infiltration and designed to retain contaminants through filtration and adsorption to particles.

A perforated pipe used to assist the draining of soils.

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.

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.

Lake Simcoe Region Conservation Authority

A lot level bioretention cell designed to receive and detain, infiltrate and filter runoff, typically used for discharge from downspouts.

The accounting of inflow and outflow of water in a system according to the components of the hydrologic cycle.

The temporary storage of stormwater to control discharge rates, and allow for sedimentation.

A bioretention BMP featuring an impermeable liner and underdrain that prevents infiltration of runoff into the underlying native soil; provides sedimentation and filtration of urban runoff as it passes through the mulch layer, engineered filter media and vegetation root zone.

A bioretention cell that features an impermeable liner that collects and treats stormwater through sedimentation and filtration only (i.e., no infiltration).

Ground depression acting as a flow control and water treatment structure, that is normally dry.

Refers to the conditions in which an organism lives and survives or the conditions in which an organism resides. These conditions can be described as aspects of a “physical”, “social” or an “economic” environment, depending on the perspective perceived by the observer.

Retrieved from "https://wiki.sustainabletechnologies.ca/index.php?title=Stormwater_planters&oldid=12509"