nyuuzyou/wikis huggingface dataset:
Filter strips: Gallery

Vegetated_filter_strip_1.jpg|
Verge flowers and unmowed grass field in Delft.JPG|Unmown wildflower meadow roadside filter strip/verge in Delft
Roadside Verge - geograph.org.uk - 410991.jpg|Filter strips are a common practice in rural road cross sections
Bioretention cell rain garden US winter.jpg|Filter strips between the bioretention facility and the adjacent parking lot reduce sediment loading to the surface of the bioretention cell. Dennis Ave Health Center, Wheaton, MD. Photo credit: Moreau1
Category:Gallery
Filter strips: TTT

Surface 	Surface
Berm height (mm) 	This is the height of the curb which constrains the overland sheet flow of water. Where the bottom of the slope discharges directly into another LID facility without impedance, the value is 0.
Surface roughness (Manning’s n) 	Lower numbers indicate less surface obstruction and result in faster flow. See Turf for ideas of a good number according to mowing practices.
Surface slope (%) 	If the slope > 3%, consider using level spreaders to reduce erosion of the surface under high flow velocities.
Soil (native underlying soil, or amended topsoil)	Soil (native underlying soil, or amended topsoil)
Thickness (mm) 	If topsoil has been amended Absorbent landscapes
Porosity (fraction) 	Suggest around 0.4, unless otherwise tested.
Field capacity (fraction) 	Will vary according to native or amended topsoil 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.
Wilting point (fraction) 	
Conductivity (mm/hr) 	
Conductivity slope 	
Suction head (mm) 	
Design drawdown time (hrs) 	Will be determined by regulatory authority, often 48 - 72 hours to reduce nuisance from mosquitoes
category:modeling
Filtration

Filtration is the process by which stormwater runoff is conveyed through a filter medium to remove solid particles and associated pollutants. Several stormwater practices use filtration through sand or gravel media as the primary mechanism for treatment of urban runoff. 
Stormwater passes through a filter based on the pressure difference on either side of the filter. In most stormwater treatment applications, the pressure difference is created by gravity (or hydraulic head). As the filter becomes clogged, higher pressure is needed to drive stormwater through the filter, until a point is reached at which flow through the treatment system must be redirected to another flow path (usually a bypass within or upstream of the system). 
==Types of filtration==
Two common types of filter media used in stormwater treatment are granular media, such as sand, and membranes: 
Granular media is a multilayer lattice or matrix that traps solids as water flows through the tortuous channels in the media. Clogging may occur when solid particles form a film or cake on top of the filter or accumulate within the media channels to the point where the channels become occluded. 
Membranes have very thin separation lattices with openings or pores that remove all particles larger than the nominal pore size of the filter at the surface, thereby acting much like a sieve. Membranes are often pleated to increase the surface area, allowing for more particles to be trapped prior to clogging.
Some filters include additives such as zeolite or iron to enhance the contaminant removal process for target water quality variables by increasing chemical adsorption and/or precipitation.
==Key system design parameters==
When sizing filtration systems for specific sites using local historical rainfall records, several key system design parameters need to be considered. These are defined in the sizing section of the Filtration MTD page. 
Non-proprietary bioretention systems are sized as filters much more conservatively based on design storms, surface ponding depth and minimum media infiltration rate. The ratio of drainage area imperviousness to the surface area of bioretention facilities (referred to as the impervious-to-pervious ratio) is often many times lower than that for filtration MTDs. This ensures longer intervals for sediment maintenance and significant reductions in stormwater volumes through infiltration.
Permeable pavements can also be considered to be a type of filter. In this case, runoff and rainwater is filtered through the surface pores or granular media between the pavers, as well as through the bedding and base layers. Most of the sediment directed onto the pavements is trapped near the surface where it can be more easily accessed for cleaning. Since permeable pavements need to maintain a high rate of infiltration to avoid ponding, the area of impervious surface draining on to them should be no larger than the area of the permeable pavement itself.
==See also==
*Filtration Manufactured Treatment Devices
*Media filters
*Pretreatment
*Oil and grit separators
Flow through media

Practices which infiltrate surface runoff through an engineered soil or filter media, and discharge through an underdrain perforated pipe include stormwater planters, and partial- and no-filtration forms of bioretention. 
The maximum flow rate from the BMP may be limited by the hydraulic conductivity of the medium, or by the properties of the perforated pipe. See Flow through perforated pipe page for guidance on estimating the maximum flow rate of a perforated pipe.
The maximum flow rate through a bed of filter media (Qmax, media, m3/s) may be calculated as:
Q_{max, media}=\frac{K_{m}\times A_{p}\times \left (\frac{h_{max}}{d_{m}} \right )}{3.6\times 10^{6}}
----
===Example calculations===
A stormwater planter with footprint of 8 x 1.5 m is planned to receive runoff from an adjacent rooftop. The initial design for the planters includes 750 mm depth of filter medium, 50 mm rock mulch, and a further ponding of 300 mm. The underdrain pipe will be embedded into high performance bedding or similar, with a strip of geotextile over the top to prevent migration of the filter media into the pipe. The lab test states that the medium has a hydraulic conductivity of 25 mm/hr. The maximum flow through the medium is calculated and then compared with the maximum flow through the perforated pipe to see if the planter will drain freely: 
Q_{max, media}=\frac{25 mm/hr\times 12\ m^{2}\times \left (\frac{1.1\ m}{0.75\ m} \right )}{3.6\times 10^{6}}=0.00012\ m^{3}/s
A partial infiltration bioretention cell with footprint of 30 x 10 m is planned to received runoff from adjacent roadways and parking facilities. The design includes 600 mm depth of filter medium, 75 mm wood-based mulch, and ponding depth of 300 mm. Two underdrain pipes will be embedded at the base of the storage reservoir. These will connect together and then have an upturn within a manhole at the downstream end to prevent discharge until the head of water reaches the top of the internal water storage reservoir clear stone aggregate. The lab test for the filter medium state that it has a hydraulic conductivity of 80 mm/hr. The downstream pipe in the manhole can convey 0.002 m3/s on a 1% slope.: 
Q_{max, media}=\frac{80 mm/hr\times 300\ m^{2}\times \left (\frac{0.975\ m}{0.6\ m} \right )\times 2}{3.6\times 10^{6}}=0.0022\ m^{3}/s
As the maximum flow rate exceeds the downstream maximum permissible flow, the design must be amended. In order of preference, some options include:
#Increasing the size of the downstream pipe to accommodate a greater flow rate;
#Reducing the depth of the filter media bed in agreement with a Landscape Architect, and increasing pretreatment (as filter bed < 600 mm deep will provide less water quality treatment); or 
#Reformulating the bioretention filter media in collaboration with the soils provider, to reduce the hydraulic conductivity.
Flow through riser

There are many configurations for multistage risers according to the flow control requirements. 
It is easiest to begin downstream and design with the the highest return period required in mind. 
e.g. start by specifying the pipe/culvert component to control the 100 year flow. 
Then to work backwards to size the lip or weir at the top of the structure to meet the next return period flow. 
The riser is then designed with flow through one or more orifices. 
Q=
\left\{\begin{matrix}
0, & Z\leq Z_{0} \\ 
C_{w}L_{w}\left ( Z-Z_{0} \right )^{1.5}, & Z_{0}\leq Z\leq Z_{0}+H_{0}\\ 
C_{d}A_{0}\sqrt{2g\left (Z-Z_{0}-0.5H_{0}\right)}, & Z_{0}+H_{0}\leq Z\leq Z_{1}\\ 
C_{w}L_{w}\left ( Z-Z_{1} \right )^{1.5}+C_{d}A_{o}\sqrt{2g\left (Z-Z_{1}\right)}, & Z_{1}<Z 
\end{matrix}\right.
==See also==
*Detention basins
*Flow control
==For review==
https://www.hydrologystudio.com/no-fail-detention-pond-design/
Forebays: Gallery

Solid splashpad.jpg|Solid splash pad preventing erosion from the flow from the inlet. Image credit Dylan Passmore
Forebay AV.jpg|Forebay connected to drainage area in the roadway with a curb cut, overflow visible in the centre of the feature, level spreading is encouraged with the rock check dams, Milwaukee, WI, Photo credit: Aaron Volkening
Forebay - Mississauga Road.JPG|Rounded 'river rock' and a series of check dams slow water from this inlet.
Inlet to bioswale - Wychwood.JPG| This forebay has a rock splash pad to slow water down before it reaches a bioswale.
Mississauga Road - Brampton - curb cuts.JPG|Incoming water from these curb cuts is slowed by river rock splash pads.
Category:Gallery
Freeboard

*In swales conveying flowing water a freeboard of 300 mm is generally accepted as a good starting point. 
*In bioretention the freeboard is the difference between the invert elevation of the inlet and overflow structure. 150 mm will usually suffice, so long as the inlet will not become inundated during design storm conditions. 
*In above grade stormwater planters, the equivalent dimension would be the difference between the invert elevation of the lip of the planter and the overflow structure (150 mm minimum).
GRCA2019

__NOTOC__
==Hydrogeological data in Ontario==
*Oakridges Water
*Provincial Groundwater Monitoring Network
*Groundwater Information Network
*Ontario Groundwater
*Surficial geology of southern Ontario
==Darcy Drainage== 
==Groundwater Mounding==
==LID lifecycle costing==
*STEPs LID costing project page
 ‎
==Other==
*MOE 2003 on Infiltration Trenches
*Source Water Protection
*Free Infiltration Rate E-Learning
===Relevant wiki pages===
*Infiltration trenches
*Infiltration chambers
*Pretreatment
Geotextiles

thumb|The properties of geotextiles vary widely.
See Clogging for notes on their application in LID structures. 
Geotextiles can be used to prevent downward migration of smaller particles in to larger aggregates, and slump of heavier particles into finer underlying courses. Geotextiles are commonly used on low strength soils (CBR<4). 
The formation of biofilm on geotextiles has also been shown to improve water quality:
*By degrading petroleum hydrocarbonsNewman AP, Coupe SJ, Spicer GE, Lynch D, Robinson K. MAINTENANCE OF OIL-DEGRADING PERMEABLE PAVEMENTS: MICROBES, NUTRIENTS AND LONG-TERM WATER QUALITY PROVISION. https://www.icpi.org/sites/default/files/techpapers/1309.pdf. Accessed July 17, 2017.
*By reducing organic pollutant and nutrient concentrations Paul P, Tota-Maharaj K. Laboratory Studies on Granular Filters and Their Relationship to Geotextiles for Stormwater Pollutant Reduction. Water. 2015;7(4):1595-1609. doi:10.3390/w7041595.
*When installing geotextiles an overlap of 150 - 300 mm should be used.
Material specifications should conform to OPSS 1860 for Class II geotextile fabrics
ONTARIO PROVINCIAL STANDARD SPECIFICATION METRIC OPSS 1860 MATERIAL SPECIFICATION FOR GEOTEXTILES. 2012. http://www.raqsb.mto.gov.on.ca/techpubs/OPS.nsf/0/2ccb9847eb6c56738525808200628de1/$FILE/OPSS%201860%20Apr12.pdf. Accessed July 17, 2017. Note when expansive clays are present, a non-infiltrating design may be necessary. If used, geotextile socks around perforated pipes should conform to ASTM D6707 with minimum water flow rate conforming to ASTM D4491 (12,263 L/min/m2 at 5 cm head). 
*Fabrics should be woven monofilament or non-woven needle punched. 
*Woven slit film and non-woven heat bonded fabrics should not be used, as they are prone to clogging.
In choosing a product, consider:
#The maximum forces that will be exerted on the fabric (i.e., what tensile, tear and puncture strength ratings are required?),
#The load bearing ratio of the underlying native soil (i.e. is the geotextile needed to prevent downward migration of aggregate into the native soil?),
#The texture (i.e., grain size distribution) of the overlying and underlying materials, and
#The suitable apparent opening size (AOS) for non-woven fabrics, or percent open area (POA) for woven fabrics, to maintain water flow even with sediment and microbial film build-up.
Percent soil/filter media passing 0.075 mm (#200 sieve)	Non-woven fabric apparent opening size (AOS, mm)	Woven fabric percent open area (POA, %)	Permittivity (sec-1)
>85 	≤ 0.3 	- 	0.1
50 - 85 	≤ 0.3 	≥ 4 	0.1
15 - 50 	≤ 0.6 	≥ 4 	0.2
5 - 15 	≤ 0.6 	≥ 4 	0.5
≤ 5 	≤ 0.6 	≥ 10 	0.5
===Performance research===
http://www.mdpi.com/2073-4441/7/4/1595/htm
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category:materials
Grain size analysis

This method of determining design infiltration rate is only suitable for coarse-textured native soils with d10 between 0.1 - 2.5 mm (i.e. soils to which the Hazen formula is applicable)San Francisco Public Utilities Commission. (2017). Determination of Design Infiltration Rates for the Sizing of Infiltration‐based Green Infrastructure Facilities. Retrieved from http://sfwater.org/modules/showdocument.aspx?documentid=9681. 
This method shall not be applied within areas of fill or in regions where hydraulic conductivity is controlled by vertical fractures in the soil matrix. 
==Procedure==
# Collect soil samples for each defined soil layer below the bottom of the proposed infiltration facility. Layers must be evaluated to the following depths, depending upon facility type:
#* For bioretention facilities, analyze each defined layer below the proposed facility bottom to a depth of at least 3 times the maximum ponding depth, but not less than 1 m.  
#* For permeable pavements, analyze each defined layer below the proposed facility bottom to a depth of at least 3 times the maximum depth of water within the base course, but not less than 1 m.  
#* For other types of infiltration facilities serving drainage areas up to 4 Ha, analyze each defined layer below the proposed facility bottom to a depth of at least 2.5 times the water storage reservoir depth, but not less than 3 m.  
# Submit the soil samples to a certified soil testing laboratory for grain-size, or particle-size distribution analysis according to ASTM D422 Standard Test Method for Particle-size Analysis of Soils.
===Data Analysis===
NB: The Hazen formula method of estimating soil permeability based on grain size distribution analysis is only suitable for coarse-textured soils with d10 between 0.1 and 2.5 millimeters Hazen, A. (1893). Some physical properties of sand and gravel with special reference to the use in filtration. 4th Annual Report, State Board of Health, Boston.. The soil permeability value estimated using the Hazen method can be considered to be the measured infiltration rate of the soil, f, in mm/h
:f=C\cdot {\left (d_{10}\right )^{2}}
Shape factors (C) to yield f in mm/h	Shape factors (C) to yield f in mm/h
Very fine to fine sand 	144000
Medium to coarse sand 	288000
==Don't forget to apply a safety correction factor before beginning your sizing calculations==
Gravel diaphragms

Gravel diaphragms are simply gravel filled trenches which act as inlet structures by redistributing concentrated flow to sheet flow: reducing the erosive power of the water and promoting infiltration. They also act as a pretreatment by settling out sediment particles before they reach any downstream structure or practice. 
If the contributing drainage area is solely turf (e.g., sports field), then the gravel diaphragms may be eliminated from the treatment train.
==Planning==
The gravel diaphragm serves two purposes. First, it acts as a pretreatment device, settling out coarse particles before they reach an infiltration practice. Second, it acts as a level spreader, maintaining sheet flow as runoff flows over the filter strip. If the contributing drainage area is steep, then larger stone should be used in the diaphragm,
*Diaphragms can be designed along curves as readily as straight lines, 
*As they are not a conveyance practice, they should be designed along a single contour line, promoting the level spreading function, 
*Flow should be directed into the device laterally.
==Design==
*Where flow comes off an impervious surface, an elevation drop of 75 to 150 mm to the surface of the diaphragm is recommended to dissipate energy, promote settling and allow for accumulation of sediment and debris between cleanings;
*Typical dimensions for the trench excavation are 300 mm deep and 600 mm wide. The trench may be any length; 
*The trench should be lined with geotextile before filling with gravel; and, 
*River rock or decorative stone may be included in a layer at the top of the gravel fill, for aesthetic value.
==Materials==
===Gravel===
The type of medium sized aggregates recommended for gravel diaphragms are described in choker layer. In some contexts it may be desirable to apply a surface layer of more decorative stone.
===Geotextiles===
==External Resources==
*VIRGINIA DCR STORMWATER DESIGN SPECIFICATION No. 2
*National Engineering Handbook Part 628 Dams Chapter 45 Filter Diaphragms
==References==
category: pretreatment
Green roof media

The green roof media used in Ontario can be classed according to proportion of composted biological material. Some existing installations use materials which comply with FLL guidelines, whilst others use a much higher proportion of compostHill, J., Drake, J., and Sleep, B. (2016). “Comparisons of extensive green roof media in Southern Ontario.” Ecological Engineering, Elsevier B.V., 94, 418–426. https://www.sciencedirect.com/science/article/abs/pii/S0925857416302804?via%3Dihub. 
ASTM International have a number of standards relating to various design considerations for green roofs. These standards provide good technical advice on the testing of systems and components.
Of particular note are:
*Standard Test Method for Maximum Media Density for Dead Load Analysis of Vegetative (Green) Roof SystemsE2399, and
*Test Method for Saturated Water Permeability of Granular Drainage Media E2396.
When these tests are completed, the results should be interpreted in relation to the objectives of the green roof. A product complying with overseas guidelines may not serve the needs of a green roof installed in Ontario. In particular, the FLL guide recommends green roof media specifications which may not provide optimal stormwater management or vegetation in our region. 
In many proprietary systems the default option for planting medium will be a granular material with very low organic matter content. However, many companies can arrange for a high organic matter alternative to be substituted if requested. 
Increasing the depth of planting medium from 10 cm to 15 cm has been shown to benefit the vegetation MacIvor JS, Margolis L, Puncher CL, Carver Matthews BJ. Decoupling factors affecting plant diversity and cover on extensive green roofs. J Environ Manage. 2013;130:297-305. https://www.sciencedirect.com/science/article/abs/pii/S0301479713006051?via%3Dihub, however stormwater retention was not improved with this increase in depth Hill, J., Drake, A. P. J., Sleep, B., and Margolis, L. (2017). “Influences of Four Extensive Green Roof Design Variables on Stormwater Hydrology.” Journal of Hydrologic Engineering. https://ascelibrary.org/doi/abs/10.1061/%28ASCE%29HE.1943-5584.0001534
 Considerations for using a 'high organic', compost based planting medium
Benefits	Disadvantages
*Increased water holding capacity, which benefits both vegetation health and stormwater retention 
*Lighter weight, even when saturated	
*Increased phosphorus concentration in runoff water.
*The lightweight material is more prone to wind erosion, and this should be accounted for in the initial design, alternatives include erosion control blankets, soil tackifiers, or Sedum mats.
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category:materials
category:green infrastructure
Green roofs: Planting

Sortable table, click on header you wish to select your green roof plants by
Scientific name 	Common name 	Soil Moisture
1=Dry
2=Med
3=Wet	Partial shade tolerance	Colour
Achillea millefolium 	Yarrow 	1-2	 	O
Allium schonaprasum 	Chives 	2-3	 	1
Aquilegia canadensis 	Wild columbine 	1-3	Y 	1
Calendula sp. 	Marigold 	2 	 	2
Carex sp. 	Sedge 	3 	Y 	O
Centaurea sp. 	Bluet 	1-2	 	3
Coreopsis grandiflora 'Early sunrise'	Large-flowered tickseed 	1-2	 	2
Coreopsis lanceolata 	Lanceleaf coreopsis 	1-2	 	2
Coreopsis tripteris 	Tickseed 	1-2	 	2
Cosmos sp. 	Cosmos 	1-3	 	1
Equisetum hymale 	Rough horsetail 	2-3	Y 	O
Erysimum sp. 	Wallflower 	1-2	 	1
Geranium maculatum 	Wild geranium 	2 	Y 	1
Geranium psilostemon 'Rozanne' 	Cranesbill Geranium 	2-3	Y 	3
Leucanthemum superbum 	Shasta daisy 	1-2	 	2
Liatris spicata 	Blazing star 	2 	 	3
Lobelia siphilitica 	Blue cardinal flower 	2-3	Y 	3
Lolium multiflorum 	Ryegrass 	1-3	Y 	O
Lupinus polyphyllus 	Large leaf lupin 	1-3	Y 	3
Monarda fistulosa 	Bee balm 	1-3	 	1
Monarda punctata 	Horsemint 	2 	 	3
Panicum virgatum 	Switchgrass 	1-3	 	O
Papaver rhoeas 	Corn poppy 	1-3	 	1
Penstemon digitalis 	White Beardtongue 	1-2	 	O
Pycnanthemum tenuifolium 	Narrowleaf mountain mint	1-2	Y 	O
Rudbeckia hirta 	blackeyed Susan 	1-3	Y 	2
Rudbeckia nitida 'Herbstsonne' 	Cutleaf coneflower 	2 	Y 	2
Rudbeckia laciniata 'Goldquelle' 	Golden glow coneflower 	2 	Y 	2
Saponaria officinalis 	Soapwort 	2-3	Y 	O
Schizachyrium scoparium 	Little Bluestem 	2 	 	O
Sedum sp. 	Stonecrop 	1-3	 	O
Sempervivum sp. 	Houseleek 	1-2	 	O
Silene sp. 	Campion 	1-2	Y 	O
Symphyotrichum novae-angliae 	New England Aster 	2 	 	3
Trifolium repens 	White clover 	3 	 	O
Heavy metals

The heavy metals noted as particularly harmful to aquatic ecosystems are:
*Chromium(Cr),
*Copper (Cu),
*Lead (Pb), and
*Zinc (Zn)Feng W, Hatt BE, McCarthy DT, Fletcher TD, Deletic A. Biofilters for Stormwater Harvesting: Understanding the Treatment Performance of Key Metals That Pose a Risk for Water Use. Environ Sci Technol. 2012;46(9):5100-5108. doi:10.1021/es203396f.
Laboratory experiments on bioretention media have demonstrated that the organic matter significantly improves retention of lead (Pb), copper (Cu), and zinc (Zn) Gülbaz S, Kazezyilmaz-Alhan CM, Copty NK. Evaluation of Heavy Metal Removal Capacity of Bioretention Systems. Water Air Soil Pollut. 2015;226(11). doi:10.1007/s11270-015-2640-y.. This research also found that extended detention of the stormwater in the cell did not improve this water quality benefit.
Cores of media were extracted from five 10 year old bioretention cells in Queensland, Auz and tested for a suite of heavy metals: “Although trace amounts of several heavy metals (most prominently Mn and Zn) were found in most of the basins, all heavy metal levels found in the soil were either below detectable limits, or within acceptable limits based on legislated health-based investigation levels.” Lucke T, Nichols PWB. The pollution removal and stormwater reduction performance of street-side bioretention basins after ten years in operation. Sci Total Environ. 2015;536:784-792. doi:10.1016/j.scitotenv.2015.07.142.
Category: Water quality