Difference between revisions of "Filter strips: TTT"
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+ | {{Clickable button|[[File:TTT.png|300 px|link=http://www.sustainabletechnologies.ca/wp/low-impact-development-treatment-train-tool/]]}} | ||
+ | [[File:LID TTT.png|thumb|[[Vegetated filter strips]] are found within the LID toolbox]] | ||
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
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|width = 210px|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. | |width = 210px|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. | + | |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. | + | |Surface slope (%)||If the slope > 3%, consider using [[level spreaders]] to reduce erosion of the surface under high flow velocities. |
|- | |- | ||
!colspan = "2" style="background: darkcyan; color: white; align = center"|Soil (native underlying soil, or amended topsoil) | !colspan = "2" style="background: darkcyan; color: white; align = center"|Soil (native underlying soil, or amended topsoil) | ||
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|Thickness (mm)||If topsoil has been amended [[Absorbent landscapes]] | |Thickness (mm)||If topsoil has been amended [[Absorbent landscapes]] | ||
|- | |- | ||
− | |Porosity (fraction)||Suggest | + | |Porosity (fraction)||Suggest around 0.4, unless otherwise tested. |
|- | |- | ||
− | |Field capacity (fraction)||Rowspan=5|Will vary according to native or amended topsoil<ref | + | |Field capacity (fraction)||Rowspan=5|Will vary according to native or amended topsoil<ref> 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.</ref> |
|- | |- | ||
− | |Wilting point (fraction) | + | |Wilting point (fraction) |
|- | |- | ||
− | |Conductivity (mm/hr) | + | |Conductivity (mm/hr) |
|- | |- | ||
− | |Conductivity slope | + | |Conductivity slope |
|- | |- | ||
− | |Suction head (mm) | + | |Suction head (mm) |
|- | |- | ||
− | |Design drawdown time (hrs)|| | + | |Design drawdown time (hrs)||Will be determined by regulatory authority, often 48 - 72 hours to reduce nuisance from [[Wildlife#Mosquitoes|mosquitoes]] |
|} | |} | ||
[[category:modeling]] | [[category:modeling]] |
Latest revision as of 22:24, 20 November 2018
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) | |
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[1] |
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 |
- ↑ 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.