nyuuzyou/wikis huggingface dataset:
Permeable pavements: Sizing

The following calculation is used to size the stone storage bed (reservoir) used as a base course. It is assumed that the footprint of the stone bed will be equal to the footprint of the pavement. The following equations are derived from the Interlocking Concrete Pavement Institute (ICPI) manual Smith, D. 2017. Permeable Interlocking Concrete Pavements; Selection, Design, Specifications, Construction, Maintenance. 5th Edition. Interlocking Concrete Pavement Institute. Chantilly VA
===For full infiltration design, to calculate the total depth of clear stone aggregate layers needed for the water storage reservoir=== 
The equation for the maximum depth of the stone reservoir (dr, max, m) is as follows: 
d_{r, max}=\frac{(RVC_{T}\times R) + RVC_{T} - (f'\times D)}{n}
 
It is important to note that R should not exceed 1 to limit hydraulic loading and help avoid premature clogging. Also important to note is that the contributing drainage area should not contain pervious areas that are sources of sediment that can lead to premature clogging. 
On highly permeable soils (e.g., infiltration rate of 45 mm/hr or greater), a maximum stone reservoir depth of 2 metres is recommended to prevent soil compaction and loss of permeability from the mass of overlying stone and stored water.
===For partial infiltration design, to calculate the depth of the storage reservoir needed below the invert of the underdrain pipe===
For designs that include an underdrain, the depth of the storage reservoir below the invert of the underdrain pipe (dr) can be calculated as follows:
d_{r}=\frac{f'\times t}{n}
 
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Where the total contributing drainage area (Ac) and total depth of clear stone aggregate needed for load bearing capacity of the pavement are known (i.e., storage reservoir depth is fixed) or if available space is constrained in the vertical dimension due to water table or bedrock elevation, the minimum footprint area of the water storage reservoir, Ar can be calculated as follows:
A_{r}=\frac{D(i - f')\times A_{c}}{d_{r} \times n}
Where:
Ac = Ai + Ap, and
Ar = Ap (i.e., assumed that the water storage reservoir area and permeable pavement area are the same)
Then adjust Ar accordingly to keep R between 0 and 1, which reduces hydraulic loading and helps avoid premature clogging.
Back to Permeable pavements
==References==
Category:Calculations
Permeable pavements: TTT

Surface 	Surface
Berm height (mm) 	This is the height of the curb which constrains the overland sheet flow of water. Where curb cuts or other outlet exists at the lowest point of the pavement, the suggested value is 0.
Surface roughness (Manning’s n)	Lower numbers indicate less surface obstruction and result in faster flow.
Suggested range for pavement 0.01 – 0.02 Oregon State Univ., Corvallis. Dept. of Civil, Construction and Environmental Engineering.; Environmental Protection Agency, Cincinnati ONRMRL. Storm Water Management Model Reference Manual Volume I Hydrology (Revised). 2016:233. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100NYRA.txt Accessed August 23, 2017.
Surface slope (%) 	Typically between 1 – 4% (>2% recommended Effective grading)
Pavement 	Pavement
Thickness (mm) 	This is the thickness of just the pre-cast blocks (or depth of asphalt/concrete poured in place).
Void ratio 	This most commonly refers to the jointing material used between precast blocks. Suggest 0.4 unless otherwise tested. Where a pervious product is poured in place, an appropriate figure should be obtained from the manufacturer.
Impervious surface fraction 	This is the proportion of the total pavement taken up with the pre-cast blocks and will vary between products; an example value may be 0.85. 
Where a pervious product is poured in place, this value will be 0.
Permeability (mm/hr) 	This is the permeability of the joint material in block systems. Where the permeability of the bulk surface is measured and known instead, the impervious fraction can be adjusted to model a block surface as continuously permeable instead.
Clogging factor 	0.5 to model a matured system?
Soil (Bedding layer?) 	Soil (Bedding layer?)
Thickness (mm) 	Depth of bedding layer
Porosity (fraction) 	Suggested value 0.4 unless otherwise tested (see OPSS aggregates)
Field capacity (fraction) 	Suggested range 0.10 - 0.12 for sand
Wilting point (fraction) 	Suggested value 0.03 for sand
Conductivity (mm/hr) 	Suggested range 100 – 250 mm/hr for sand
Conductivity slope 	Suggested value 45 for sand
Suction head (mm) 	Suggested value 50 for sand
Storage 	Storage
Thickness (mm) 	Depth of all aggregate bases
Void ratio 	Suggested value 0.4 unless otherwise tested
Seepage rate (mm/hr) 	Infiltration rate of native soil
Clogging factor 	0.5 to model a matured system?
Design drawdown time (hrs) 	Maybe 72 or 96 hours? See Drainage time
Drain (underdrain) 	Drain (underdrain)
Flow coefficient 	Suggested value 1
Flow exponent 	Suggested value 1
Offset height 	This is the height from the base of the cell to the height at which the drain discharges. In some designs this may be the height of the perforated pipe within the storage layer. In other designs this height is adjusted by creating an upturn in the discharge pipe. Permeable pavements
category: modeling
Permeameters

==Principle==
A variety of field permeameters have been developed locally, and are readily available to purchase or to hire. 
They speed up analysis (somewhat) and add some degree of accuracy to a simple percolation test by employing the Mariotte bottle principle to maintain a steady water level (fixed head condition) within the test well. 
They have relative benefits and limitations in their use, and as they are proprietary devices, they each have manufacturers specific recommendations for their use. 
Sampling strategies for their use is found on Design infiltration rate.
==Using a permeameter== 
===Packing list===
*Permeameter
*Auger kit
*Water container (will water need transporting to the test site?)
*Laptop with spreadsheet or field forms
*Onsite repair kit:
**Strong adhesive tape
**Knife
**Hose clamps 
**Screwdriver
**Vacuum grease
*Logistics:
**Tarpaulin to kneel/work on
**Seat?
**Sunscreen and/or umbrella?
===Permeameter assembly (Guelph permeameter)=== 
There are three thin inner tubes (shown in dark red): 
*the central tube is the longest and sits within the reservoir assembly,
*the bottommost tube has a washer/seal apparatus on the end which does not attach to the central tube, 
*the top tube is the shortest and has an open end where it does not attach to the central tube. 
The reservoir assembly comprises two tubes of the same length:
*the outer (shown in green) is unmarked,
*and there is a mid-sized tube with graduations in millimeters, 
There are two further mid-sized tubes (in orange):
*the longer of these has a cup-shaped, filter-like ‘foot’ and should have a funnel shaped bushing threaded on (shown semi-transparent); this tube goes onto the base of the reservoir, 
*the shorter tube has graduations in millimeters and no other components attached; it slides onto the very top around the shortest thin tube. 
At the top of the reservoir section there are three small but important components to note: 
*a short flexible hose to regulate air going into the reservoir; this should have a plastic ring associated to close it off, 
*a hole with a rubber plug; this is used to fill the reservoir with water (not shown),
*a moveable ‘indicator’ on the inner tube; it is a small cylinder of plastic threaded onto the tube which come directly from the reservoir. 
The order in which the parts are assembled will be dictated by which connectors can fit through which holes within the connecting plates. It is easiest to connect up the thinnest tubes first. 
Find a clear flat piece of ground (or a picnic table) and assemble all of the parts horizontally to reduce strain on the connectors.
==Guelph Permeameter Field Sheets==
Click below to download and print the Guelph Permeameter field sheet to be used to test your site(s)' infiltration rate 
==External links==
*Guelph Permeameter
*ETC Pask Permeameter
*CSSi Permeameter
Photographs

__NOTOC__
This is a copy of many of the photographs we've gathered for the site, particularly those illustrating structural BMPs or specific features. Note some photographs are from external sources, references listed in descriptions. If you can't find what you're after, try checking other people's LID photograph databases. If you're seeking photographs of plant species, we've mostly linked content directly from the Wikimedia Commons.
==BMPs==
===Bioretention cells===
===Bioswales===
===Dry ponds===
===Extended tree pits===
===Filter Strips===
===Grass Swales===
===Infiltration chambers===
===Infiltration trenches===
===Permeable Pavement===
===Soil cells===
===Stormwater planters===
==Details==
===Check dams===
===Curb cuts===
===Curb extensions===
===Forebays===
===Overflow structures===
===Trench drains===
==Other databases==
Our content is licensed for reuse through Creative Commons. 
Be sure to check the licensing of other people's online work before reusing or adapting. 
*Stormwater and Green Infrastructure Flickr Album by Chesapeake Bay Program
*Green Roofs of Southern Ontario Flickr Collections by Jenny Hill
Pipes

Perforated pipes are a common component of underdrains used in bioretention, permeable pavements, infiltration trenches and exfiltration systems. 
Pipes should be manufactured in conformity with the latest standards by the Canadian Standards Association (CSA) or ASTM International.
*Perforated pipes should be continuously perforated, smooth interior HDPE or PVC.
**Wherever possible pipes should be ≥200 mm internal diameter to reduce potential of freezing and to facilitate push camera inspections and cleaning with jet nozzle equipment. 
**Smooth interior facilitates inspection and maintenance activities; internal corrugations can cause cameras or hydrojetting apparatus to become snagged. 
**A perforated pipe with many rectangular slots has better drainage characteristics than a pipe with similar open area provided by fewer circular holes Hazenberg, G., and U. S. Panu (1991), Theoretical analysis of flow rate into perforated drain tubes, Water Resour. Res., 27(7), 1411–1418, doi:10.1029/91WR00779..
*Non-perforated pipes should be used for conveyance of stormwater to and from the facility, including overflow. It is good practice to extend the solid pipe approximately 300 mm within the reservoir or practice to reduce the potential for native soil migration into the pipe. 
Perforated Pipe 550x550.jpg|Pipe with slotted perforations
Pipe with connector.jpg|Perforated pipes awaiting installation, note the 45 degree couplings used to facilitate push camera inspection and jet nozzle cleaning. 
See also: Flow through perforated pipe
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Category:Materials
Planters: Sizing

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
Rain gardens: Gallery

File:LWSNAP Raingarden.PNG| Lake Wilcox Snap project that installed Rain garden features along with bioswales, rainwater harvesting barrels and Permeable pavement parking lots of residents. Read more about the retrofits, their performance and the overall project in the, Lake Wilcox SNAP Embracing Nature in the Community. Photo credit: CVC, 2016.
File:Mississauga Lakeview bioret 1.JPG|Rain Gardens located on private, lot-level properties in the Lakeview Neighborhood in Mississauga, ON. Read more about the project here, in the Lakeview Village Sustainability Strategy DRAFT. 
File:Rain garden publicschool.PNG|Rain garden LID feature located at a public school, used both for practical water retention, infiltration and water quality instrumental benefits and can be used as a valuable 'teaching-tool' for grade school children. 
File:Raingarden rainbarrel CVC 2022.PNG|Typical close up of a rain garden and some of the plants located in the low hydric zone. This low zone is often referred to as the extended detention or shoreline fringe area. This area is frequently inundated during storm events, and is well-drained between rainfall events. CVC, 2022.
File:SNAP Lk Wilcox FYM rain garden 1.jpg|An example of a finished house with multiple LID practices installed within the Lake Wilcox Snap project site. Read more about the neighbourhood in the, Lake Wilcox SNAP Embracing Nature in the Community. Photo credit: CVC, 2016.
File:SNAP Lk Wilcox FYM rain garden 3.JPG|A close up of the rain garden within the Lake Wilcox SNAP program, with a rock-lined swale directing water from the home's downspouts towards the feature. Photo credit: CVC, 2016.
File:Soil moisture zones levels.PNG|600px|thumb|A simplified schematic depicting the three primary zones associated with soil moisture levels and the appropriate plant species selected for each zone's specific soil characteristics, best adapted to the area's growing conditions. (Source: CVC, 2022)CVC. 2022. Native Plants for Rain-ready Landscapes> plant these native wildflowers, grasses, shrubs and groundcovers to help manage stormwater - beautifully. cvc.ca/GreenYourProperty. https://cvc.ca/wp-content/uploads/2022/03/com_lo_rain-ready-guide_20220328-FINAL3.pdf
Category:Gallery
Rainwater harvesting: Sizing and modeling

===Simple===
The following approximations 
Five percent of the average annual yield can be estimated:
Y_{0.05} = A_{c} \times C_{vol,A}\times R_{a} \times e \times 0.05
*Filter efficiency (e) can be reasonably estimated as 0.9 pending manufacturer’s information.
*In a study of three sites in Ontario, STEP found the annual Cvol, A of the rooftops to be around 0.8 . This figure includes losses to evaporation, snow being blown off the roof, and a number of overflow events.
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Five percent of the average annual demand can be estimated:
D_{0.05} = P_{d} \times n\times 18.25
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Then the following calculations are based upon two criteria:
# A design rainfall depth is to be captured entirely by the RWH system.
# The average annual demand (D) is greater than the average annual yield (Y) from the catchment. 
When \(Y_{0.05}/D_{0.05}<0.33\), the storage volume required can be estimated:
V_{S} = A_{c} \times C_{vol,E}\times R_{d} \times e
*Careful catchment selection means that the runoff coefficient, for an individual rainstorm event (Cvol, E) should be 0.9 or greater.
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Finally, when \(0.33<Y_{0.05}/D_{0.05}<0.7\), the total storage required can be estimated by adding Y0.05:
TotalStorage = V_{S} + Y_{0.05}
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==STEP Rainwater Harvesting Tool==
The Sustainable Technologies Evaluation Program have produced a rainwater harvesting design and costing tool specific to Ontario. The tool is in a simple to use Excel format and is free to download.
==STEP Treatment Train Tool==
Rainwater harvesting: TTT
==Cistern dimensions==
 
The connections into and out of a rainwater cistern can have a dramatic effect on the actual usable volume. The only usable water within the cistern is that above the height of the pump intake, and below the invert of the overflow outlet. This dimension can easily become constrained where the outlet must lie beneath the frost line and where a high powered pump is required to elevate the water many storeys. 
* The depth of storage between the elevation of the inlet and overflow is unusable space, so the overflow should be located towards the top of the cistern.
* The depth of storage beneath the pump inlet is unusable, but may also be a useful zone for sediment to settle. A custom or cast-in-place vault could minimise this unused volume by tapering towards the the base. 
category:modeling
Rainwater harvesting: TTT

Once the size of cistern has been determined, it can easily be modeled in many open source and proprietary applications. 
For planning purposes, a RWH system can be integrated into a site plan as a storage element, using the TTT: 
#Create a subcatchment area to harvest rainwater. Maybe this is a one or more building rooftops?
#:Select the subcatchment button and draw over the desired catchment area, close the are with a double click. 
#Specify the RWH cistern as the outlet for the subcatchment(s). 
#:Select the Storage button and place it nearby to the associated catchment. 
A roof as a subcatchment (key parameters)
Land Use 	Land Use
Roof (%) 	100
Subcatchment	Subcatchment
Outlet 	Select the name of your RWH cistern storage element (see below)
A rainwater harvesting cistern as a storage element (key parameters)
Stage Storage 	Stage Storage
Name 	Important to have a unique name, to associate with the subcatchment (harvesting area)
Storage type 	No removal
Bottom elevation (m) 	This will be 0 for installations at ground level, but will often be underground. This is of greater importance when the overflow is coupled to another component within a treatment train
Maximum depth (m) 	Height of the RWH cistern
Lined/unlined 	Lined
Evaporation factor 	0
Curves 	Curves
The Curves table is designed to accommodate ponds of roughly conical dimensions. Rainwater cistern are usually cuboid or cylindrical in shape, so that the area (m2) will remain the same throughout the depth. The top and bottom dimensions can be placed within the first two rows of the table.	The Curves table is designed to accommodate ponds of roughly conical dimensions. Rainwater cistern are usually cuboid or cylindrical in shape, so that the area (m2) will remain the same throughout the depth. The top and bottom dimensions can be placed within the first two rows of the table.
category:modeling
Reservoir aggregate

This article gives recommendations for aggregate to be used to store water for infiltration. This is usually called 'clear stone' at aggregate yards. 
To see an analysis of Ontario Standard Specifications for granular materials, see OPSS aggregates. 
For advice on decorative surface aggregates see Stone
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Gravel used for underdrains in bioretention, infiltration trenches and chambers, and exfiltration trenches should be 20 or 50 mm, uniformly-graded, clean (maximum wash loss of 0.5%), crushed angular stone that has a porosity of 0.4Porosity of Structural Backfill, Tech Sheet #1, Stormtech, Nov 2012, http://www.stormtech.com/download_files/pdf/techsheet1.pdf accessed 16 October 2017 .
The clean wash to prevent rapid accumulation of fines from the aggregate particles in the base of the reservoir. The uniform grading and the angularity are important to maintain pore throats and clear voids between particles. (i.e. achieve the porosity). Porosity and permeability are directly influenced by the size, gradation and angularity of the particles Judge, Aaron, "Measurement of the Hydraulic Conductivity of Gravels Using a Laboratory Permeameter and Silty Sands Using Field Testing with Observation Wells" (2013). Dissertations. 746. http://scholarworks.umass.edu/open_access_dissertations/746. See jar test for on-site verification testing protocols. 
Gravel with structural requirements should also meet the following criteria:
*Minimum durability index of 35
*Maximum abrasion of 10% for 100 revolutions and maximum of 50% for 500 revolutions
Standard specifications for the gradation of aggregates are maintained by ASTM D2940
File:Particle void ratio.png|The highest porosity is found in uniformly graded aggregate, as there are no smaller particles to occupy the inter-particle pores. 
File:Particle permeability.png|Higher permeability is found in larger, angular, uniformly graded aggregate. This is due to larger pore sizes and lower tortuosity. 
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category:materials
Retention swales

These sizing equations are suggested for use in calculating the capacity of swales which have a larger proportion of surface flow. i.e. grass swales, rather than bioswales. 
In many cases the length of swale required will exceed the available space, so that an underground infiltration trench or a dry pond will be a preferred solution. 
===Triangular channel===
Sizing a triangular channel for complete volume retention:
L=\frac{151,400Q_{p}^{\frac{5}{8}}m^{\frac{5}{8}}S^{\frac{3}{16}}}{n^{\frac{3}{8}}\left (\sqrt{1+m^{2}} \right )^{\frac{5}{8}}q}
===Trapezoidal channel===
Sizing a trapezoidal channel for complete volume retention:
L=\frac{360,000Q_{p}}{\left\{ b+2.388\left[\frac{Q_{p}n}{\left(2\sqrt{1+m^{2}-m}\right)S^{\frac{1}{2}}}\right ]^{\frac{3}{8}}\sqrt{1+m^{2}} \right \}q}
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Category:Infiltration
Category:Green infrastructure
Category:Modeling
Ribbon test

<pdf>File:Determining soil texture using -ribboning technique.pdf</pdf>
From State of New South Wales through the Department of Trade and Investment, Regional Infrastructure and Services, 2014. A step-by-step approach known as the 'Ribbon Test" used to help assess soil textures in a collected sample with varying layers identified - as shown on https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0005/164615/determining_soil_texture_using_-ribboning_technique.pdf
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Riprap: Gallery

IMG_4683.jpg|Riprap directing the flow from the curb cut into a bioswale in Brampton, ON. (Photo Source: CVC, 2020)
IMG_1046.jpg|Riprap directing the flow from the log flume into a rain garden at Belfountain P.S., Belfountain, ON. (Photo Source: CVC, 2021)
IMG_1580.jpg|Riprap conveying the flow from the adjacent field into a rain garden at Janet I. McDougald P.S., Mississauga, ON. (Photo Source: CVC, 2021)
Category:Gallery
Runoff volume control targets

Typically designed to handle the smaller, most frequent storm events, LID practices in Ontario are usually sized according to the 90th percentile event. In many areas this translates into events that are < 30 mm in depth. Note that 25 mm is considered to be a suitable representation of the ‘first flush’ volume, and that controlling this amount of runoff may provide stormwater engineers with control over 90 % of the mean annual pollutant load Pitt, R. 1999. Small Storm Hydrology and Why it is Important for the Design of Stormwater Control Practices. In: Advances in Modeling the Management of Stormwater Impacts, Volume 7. Computational Hydraulics International, Guelph, Ontario and Lewis Publishers/CRC Press. 1999.
===Runoff Volume Control Target (RVCT)=== 
==See also==
*Understanding rainfall statistics
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SWM ponds

Stormwater management (SWM) ponds aren't a low impact development strategy. 
There are lots of other existing guides out there to help you design a SWM pond or 'wet pond'Ontario Ministry of the Environment, Conservation and Parks, 2003, Stormwater Management Planning and Design Manual https://www.ontario.ca/document/stormwater-management-planning-and-design-manual-0. 
We encourage you to try and use LID principles; distribute water quality treatment and low flow events through the use of BMPs across your site, and deal with flood volumes with underground infiltration chambers or a nice amenity space in a dry pond.
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