Difference between revisions of "Talk:Bioretention Design Guide"
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! Table 1: !! Bioretention media composition !! !! !! !! !! | |||
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| || || Sand || Soil Fines || Organic || P-Index, milligram/kg || Gravel | |||
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| Water Quality Blend || || 60-70 % || < 5% clay || 15-25 % || 10-30 || | |||
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| Enhanced filtration blend || || 70-85 % || || 15-30 % || 10-30 || | |||
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| North Carolina WQB || || 85-88 % || 8-12 % || 3-5 % || 10-30 || | |||
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| Mix D by dry Weight || || 60-75 % || 25-40 % || 2-5 % || || < 12 % | |||
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| Mix E || || 60-80 % || 20-40 % MnDot 3890 grade 2 compost || 30% || || | |||
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| Mix F by weight || || 75% loamy sand || 25 % MnDot grade 2 compost || || || | |||
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{| class="wikitable" | |||
! colspan="4" style="background: orange; color: black"|Table 2: Minimum bioretention soil media depths recommended to target specific stormwater pollutants | |||
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!|Pollutant || Depth of Treatment with upturned elbow or elevated underdrain || Depth of Treatment without underdrain or with underdrain at bottom || Minimum depth | |||
|- | |||
| Total suspended solids (TSS) || Top 2 to 3 inches of bioretention soil media || Top 2 to 3 inches of bioretention soil media || Not applicable for TSS because minimum depth needed for plant survival and growth is greater than minimum depth needed for TSS reduction | |||
|- | |||
| Metals || Top 8 inches of bioretention soil media || Top 8 inches of bioretention soil media || Not applicable for metals because minimum depth needed for plant survival and growth is greater than minimum depth needed for metals reduction | |||
|- | |||
| Hydrocarbons || 3 to 4 inch Mulch layer, top 1 inch of bioretention soil media || 3 to 4 inches Mulch layer, top 1 inch of bioretention soil media || Not applicable for hydrocarbons because minimum depth needed for plant survival and growth is greater than minimum depth needed for hydrocarbons reduction | |||
|- | |||
| Nitrogen || From top to bottom of bioretention soil media; Internal Water Storage Zone (IWS) improves exfiltration, thereby reducing pollutant load to the receiving stream, and also improves nitrogen removal because the longer retention time allows denitrification to occur underanoxic conditions. || From top to bottom of bioretention soil media || Retention time is important, so deeper media is preferred (3 foot minimum) | |||
|- | |||
| Particulate phosphorus || Top 2 to 3 inches of bioretention soil media. || Top 2 to 3 inches of bioretention soil media. || Not applicable for particulate phosphorus because minimum depth needed for plant survival and growth is greater than minimum depth needed for particulate phosphorus reduction | |||
|- | |||
| Dissolved phosphorus || From top of media to top of submerged zone. Saturated conditions cause P to not be effectively stored in submerged zone. || From top to bottom of bioretention soil media || Minimum 2 feet, but 3 feet recommended as a conservative value; if IWS is included, keep top of submerged zone at least 1.5 to 2 feet from surface of media | |||
|- | |||
| Pathogens || From top of soil to top of submerged zone. || From top to bottom of bioretention soil media || Minimum 2 feet; if IWS is included, keep top of submerged zone at least 2 feet from surface of media | |||
|- | |||
| Temperature || From top to bottom of bioretention soil media; Internal Water Storage Zone (IWS) improves exfiltration, thereby reducing volume of warm runoff discharged to the receiving stream, and also improves thermal pollution abatement because the longer retention time allows runoff to cool more before discharge. || From top to bottom of bioretention soil media || Minimum 3 feet, with 4 feet preferred | |||
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{| class="wikitable" | |||
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! colspan="2" style="background: orange; color: black"|Table 3: Recommended minimum setback requirements | |||
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! style="backgroung=green; color:white"|Setback from|| Minimum Distance (m) | |||
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| Property Line || 10 | |||
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| Building Foundation* || 10 | |||
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| Private Well || 50 | |||
|- | |||
| Septic System Tank/Leach Field || 35 | |||
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| * Minimum with slopes directed away from the building || | |||
|} | |} |
Revision as of 15:52, 25 September 2017
LID Practice | CANADA | United States | ||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Bioretention | CVC+TRCA (Factsheets-2010) | CVC-Construction Guide-2012 | CVC-Retrofit Guide-2014 | Toronto- 2016 | LID-SWM Guide 2010 | LID-Design Guide Edmonton- 2014 | New York State SWM Design Manual-2015 | Massachusets SW BMP-2013 | District of Columbia-SWM Guidebook-2010 | San Diego LID Handbook-2014 | Alabama LID Handbook-2013 | W. Virginia-SWM design guidance manual-2012 | Rhode Island-SW design & Installation Standards Manual-2012 | Pennsylvania-City of Philadelphia green St. design manual-2014 | Minnesota SW Manual-2017 | Tennessee-LID Development-SWM 2016 | Texas-LID Technical Guidance Manual-2013 | Oregon SWM Manual-2014 | Oregon State Univ. Fact Sheets-2011 | |
Filter media depth (m) | ||||||||||||||||||||
Depth | 1-1.25 | 1-1.25 | 1-1.25 | 0.5-1.0 | >= 2.5 ft. | |||||||||||||||
Composition | ||||||||||||||||||||
Topsoil | 30-50% | 20-30 % | 8-20 % | Table 1 & 2 (below) | ||||||||||||||||
sand | 85-88 % | Fine sand=0-17%, Coarse to medium sand=71-92 % | 85-88 % | 85-88 % | 85-88 % | 50-85 % | 50-70 | 40% | 85-88 % | 65% sand, 20% sand loam | 85-88 % | 70-88 % | 85-88 % | 50-80 % | 70-85 % (sandy loam) | 85-88 % | 66% | 60% (sandy loam) | ||
Fines(silt and clay) | 8-12 % | 8-12 % | 8-12 % | 7-12 % | 8-12 % | 10-15% (silt),3-10% (clay), both combined, max 20% | clay < 5% | 8-12 % | 8-12 % | 0-12 % silt, 0-2 % clay | Silt 40% , Clay 10% | 10-20% (silt), max. 10% (clay) | 8-12 % | |||||||
gravel | 15% | |||||||||||||||||||
Organic matter | 3-5 % | 3-5 % | 3-5 % | 3-5 % | 3-5 % | 5-10% | 5% | 30-40 % | 1-5 % | 2-5 % | 3-15 % | 3-5 % | 3-5 % | 2-10 % | 5-10 % | 2-5 % | 33% | 40% | ||
P-index value | 10-30 ppm | 12-30 ppm | 10-30 ppm | 10-30 | < 15 | |||||||||||||||
Soluble salts | < 2.0 mmhos/cm | |||||||||||||||||||
Cationic exchange capacity | > 10 meq/100 g | 10 meq/100 g | > 10 meq/100 g | > 10 meq/100 g | > 10 meq/100 g | > 5 meq/100 g | > 10 | > 5 | > 10 | > 10 | > 5 | |||||||||
pH | 5.5-7.5 | 5.5-7.5 | 5.5-7.5 | 5.5-7.5 | 5.5-7.5 | 5.5-7.5 | 6-8 | 6-7 | 6-8.5 (WQ blend) | 6-8 | 5.5-7.5 | |||||||||
Phosphorus | 10-30 ppm | Table 1 & 2 (below) | ||||||||||||||||||
Infiltration rate | > 25 mm/hr | > 25 mm/hr | > 25 mm/hr | > 25 mm/hr | ||||||||||||||||
Surface resistance | <= 110 PSI | |||||||||||||||||||
Sub-surface resistance | <= 260 PSI | |||||||||||||||||||
Saturated hydraulic conductivity , mm/hr | 25 min. | |||||||||||||||||||
P-Content | 10-30 | < 15 ppm | 7-23 mg/kg | |||||||||||||||||
Compost (optional) | 15-25% | 15% | ||||||||||||||||||
Gravel storage | ||||||||||||||||||||
Void space ratio | 0.4 | 0.4 | ||||||||||||||||||
Depth | min. 300 mm | min. 300 mm | min. 300 mm | |||||||||||||||||
Diameter(clear stone) | 50 mm | 50 mm | 50 mm | |||||||||||||||||
Pea gravel choking layer | depth (mm) | 100 | 100 | 100 | ||||||||||||||||
diameter (mm) | 3-10 | 3-10 | ||||||||||||||||||
Mulch | ||||||||||||||||||||
Depth | 75 mm | <=75 mm | 75 mm | 75 mm | 70-80 | |||||||||||||||
Overflow | ||||||||||||||||||||
Overflow invert above the filter bed surface | 150-250 | <= 250 mm | ||||||||||||||||||
Monitoring well | ||||||||||||||||||||
Vertical perforated pipe diameter | 100-150 mm | 100-150 mm | 100-150 mm | 100-150 mm | ||||||||||||||||
Underdrain | ||||||||||||||||||||
Required when infiltration rate | < 15 mm/hr | < 15 mm/hr | < 13 mm/hr | |||||||||||||||||
Diameter | min. 100 mm(200 mm recommended) | min. 100 mm, 200 mm is recommended | min. 200 mm | min. 100 mm(200 mm recommended) | 200 mm | 4 inches | ||||||||||||||
Depth above the gravel storage layer | 100 mm | 100 mm | ||||||||||||||||||
Available head beween the inflow point and the downstream stream drain invert | 1-1.5 m | 1-1.5 m | Typical CDA 0.1-2.5 acres of 100% IP(<0.5 no underdrain), alternative to checking layer is needle punched non-woven geotextile | |||||||||||||||||
Contributing drainage area | ||||||||||||||||||||
Typical | 100 m2 to 0.5 hectare | 100 m2 to 0.5 hectare | 0.5-2 acres preferred, max 5 acres, BR min. size 200 ft2 | 5 acres | ||||||||||||||||
Maximum recommended | 0.8 hectare | 0.8 hectare | ||||||||||||||||||
Setback from building Foundation(m) | 4 | 4 | 4 | 3 (clay), 5 (heavy clay) | see table 3 below | |||||||||||||||
(Impervious drainage/treatment facility) area | 5:1 to 15:1 | 5:1 to 15:1 | 5:1 to 15:1 | < 5:1 loading ratio (DA to IA, DA 100% IP) | SA of BR 3 to 6% of CDA | sized at 5-8 % of IPCDA | BR SA 3-6% of CDA | CDA < 5 acres | CDA < 2.5 acres | CDA < 5 acres | BR SA: 6-15 % of IP area | |||||||||
Contributing Slope (%) | 1-5 | 1-5 | >1 % and < 33% | |||||||||||||||||
Slope of the surface, % | <= 1% | |||||||||||||||||||
Water table depth | min. 1.0 m | min. 1.0 m | > 1.8 | 3 ft. | ||||||||||||||||
Outlet | min. 100 mm above the bottom of the facility | Difference in elevation between inflow and outflow =4-6 ft (when underdrain is used) | ||||||||||||||||||
Maximum ponding depth above the filter bed surface | 150-250 mm | 250 mm | 150-250 mm | 350 mm | 18 inch | |||||||||||||||
Facilties receiving road runoff are not located within time of travel | 2 | 2 | ||||||||||||||||||
wellhead protection areas, year | ||||||||||||||||||||
Drainage time of ponded water after the end of storm event , hr | 24 (48 recommd.) | < 48 (2 yr. design) | Max. 48 hr. | |||||||||||||||||
Inlet design for non-point source-grass filter buffer, m | 0.5-3.0 | |||||||||||||||||||
Surface area/Contributing drainage area, % | 10-20 % | 10-20 % | 3.0-30 % | (5-10)%- min. 200 ft2 | ||||||||||||||||
Contributing impervious area | < 4.0 ha. | ` | < 15000 ft2 | |||||||||||||||||
Facility flow velocity | < 0.3 m/s-planted area | <= 1 ft/sec, tree-shurb-mulch cell | ||||||||||||||||||
< 0.9 m/s- mulched zone | <= 3 ft/sec , grassed cell | |||||||||||||||||||
Discharge velocity (outlet point) | < 4 ft/sec | |||||||||||||||||||
Side slope (H:V) | 4:1 preferred(max 2:1) | 3:1 (H:V) | ||||||||||||||||||
Surface geometery (length/width) | 2:1 | |||||||||||||||||||
Infiltration trench (optional) | ||||||||||||||||||||
Depth, m | 0.5-1.0 | |||||||||||||||||||
Width, m | 1.0-6.0 | |||||||||||||||||||
Bottom slope, % | 0 | |||||||||||||||||||
C/N Ratio | 12:1-25:1 | |||||||||||||||||||
Table 1: | Bioretention media composition | |||||
---|---|---|---|---|---|---|
Sand | Soil Fines | Organic | P-Index, milligram/kg | Gravel | ||
Water Quality Blend | 60-70 % | < 5% clay | 15-25 % | 10-30 | ||
Enhanced filtration blend | 70-85 % | 15-30 % | 10-30 | |||
North Carolina WQB | 85-88 % | 8-12 % | 3-5 % | 10-30 | ||
Mix D by dry Weight | 60-75 % | 25-40 % | 2-5 % | < 12 % | ||
Mix E | 60-80 % | 20-40 % MnDot 3890 grade 2 compost | 30% | |||
Mix F by weight | 75% loamy sand | 25 % MnDot grade 2 compost |
Table 2: Minimum bioretention soil media depths recommended to target specific stormwater pollutants | |||
---|---|---|---|
Pollutant | Depth of Treatment with upturned elbow or elevated underdrain | Depth of Treatment without underdrain or with underdrain at bottom | Minimum depth |
Total suspended solids (TSS) | Top 2 to 3 inches of bioretention soil media | Top 2 to 3 inches of bioretention soil media | Not applicable for TSS because minimum depth needed for plant survival and growth is greater than minimum depth needed for TSS reduction |
Metals | Top 8 inches of bioretention soil media | Top 8 inches of bioretention soil media | Not applicable for metals because minimum depth needed for plant survival and growth is greater than minimum depth needed for metals reduction |
Hydrocarbons | 3 to 4 inch Mulch layer, top 1 inch of bioretention soil media | 3 to 4 inches Mulch layer, top 1 inch of bioretention soil media | Not applicable for hydrocarbons because minimum depth needed for plant survival and growth is greater than minimum depth needed for hydrocarbons reduction |
Nitrogen | From top to bottom of bioretention soil media; Internal Water Storage Zone (IWS) improves exfiltration, thereby reducing pollutant load to the receiving stream, and also improves nitrogen removal because the longer retention time allows denitrification to occur underanoxic conditions. | From top to bottom of bioretention soil media | Retention time is important, so deeper media is preferred (3 foot minimum) |
Particulate phosphorus | Top 2 to 3 inches of bioretention soil media. | Top 2 to 3 inches of bioretention soil media. | Not applicable for particulate phosphorus because minimum depth needed for plant survival and growth is greater than minimum depth needed for particulate phosphorus reduction |
Dissolved phosphorus | From top of media to top of submerged zone. Saturated conditions cause P to not be effectively stored in submerged zone. | From top to bottom of bioretention soil media | Minimum 2 feet, but 3 feet recommended as a conservative value; if IWS is included, keep top of submerged zone at least 1.5 to 2 feet from surface of media |
Pathogens | From top of soil to top of submerged zone. | From top to bottom of bioretention soil media | Minimum 2 feet; if IWS is included, keep top of submerged zone at least 2 feet from surface of media |
Temperature | From top to bottom of bioretention soil media; Internal Water Storage Zone (IWS) improves exfiltration, thereby reducing volume of warm runoff discharged to the receiving stream, and also improves thermal pollution abatement because the longer retention time allows runoff to cool more before discharge. | From top to bottom of bioretention soil media | Minimum 3 feet, with 4 feet preferred |
Table 3: Recommended minimum setback requirements | |
---|---|
Setback from | Minimum Distance (m) |
Property Line | 10 |
Building Foundation* | 10 |
Private Well | 50 |
Septic System Tank/Leach Field | 35 |
* Minimum with slopes directed away from the building |