Difference between revisions of "Filter strips: TTT"

From LID SWM Planning and Design Guide
Jump to navigation Jump to search
m
Line 9: Line 9:
 
|Surface roughness (Manning’s n)||Lower numbers indicate less surface obstruction and result in faster flow. Suggested range for mown grass (dependent on density) 0.03 – 0.06 <ref name = SWMM> 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>
 
|Surface roughness (Manning’s n)||Lower numbers indicate less surface obstruction and result in faster flow. Suggested range for mown grass (dependent on density) 0.03 – 0.06 <ref name = SWMM> 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>
 
|-
 
|-
|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)

Revision as of 02:51, 6 November 2017

TTT.png

Vegetated filter strips are found within the LID toolbox
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. Suggested range for mown grass (dependent on density) 0.03 – 0.06 [1]
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 range 0.35 – 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) ?
  1. 1.0 1.1 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.