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Swales: 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:Swale TTT.png|thumb|Swale element in TTT menu]]
[[File:Weir TTT.png|thumb|Weir elements may be incorporated as check dams for detailed design]]
 
It is recommended that grass and [[enhanced grass swales]] be modelled using the 'Swale' element in the TTT. A 'swale' has to connect two existing elements within the TTT
[[Bioswales]] or dry swales, which have amended filter media, should be modelled as [[Bioretention: TTT|bioretention cells]].
The alternative is to use the 'enhanced swale' within the LID toolbox, but this incorporates fewer design parameters (and doesn't account for infiltration).
 
{| class="wikitable"
|+A 'swale' as a conveyance element in the TTT (key parameters)
|-
!colspan = "2"|Name||User-assigned swale nameGeneral Info
|-
|Upstream Node||Name of node on the inlet end of the swale (which is normally the end at higher elevation)
|-
|Downstream Node||Name of node on the outlet end of the swale (which is normally the end at lower elevation)
|-
|Length Manning's Roughness||Lower numbers indicate less surface obstruction and result in faster flow. <br>Suggested range for [[Turf|mown grass]] (mdependent on density)||Length 0.03 – 0.06 <ref name = SWMM> Oregon State Univ., Corvallis. Dept. of the swaleCivil, 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>
|-
|Manning's RoughnessUpstream Invert (m)||Manning's roughness coefficientDepth of swale invert above node invert at inlet end of the swale
|-
|Upstream Downstream Invert Offset (m)||Depth or elevation of the swale invert above the node invert at inlet the outlet end of the swale
|-
!colspan = "2" |Downstream Invert Offset (m)||Depth or elevation of the swale invert above the node invert at the outlet end of the swaleCross section
|-
|Maximum Depth (m)||Depth of the swale
|-
|Bottom Width (m)||Bottom width of the trapezoidal swale (i.e., open channel)<br> For a triangular channel, enter 0
|-
|Left Side Slope (m/m)||Left side slope (run/rise). [[Enhanced grass swales #Design|Suggested value of 3 or 4 if design permits.]]
|-
|Right Side Slope (m/m)||Right side slope (run/rise). Suggested value of 3 or 4 if design permits.
|-
|Seepage (mm/hour)||Rate Infiltration rate of seepage loss native (or amended) soil|}  {| class="wikitable"|+ Parameters for 'enhanced swales' in the LID toolbox of the TTT|-!colspan = "2" |Surface|-|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. <br>Suggested range for [[Turf|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 surrounding soilslope > 3%, use [[Check dams]] to create temporary ponding, increase infiltration, and slow flow to reduce erosion. |-|Swale side slopes (run/rise)||[[Enhanced grass swales #Design|Suggested value of 3 or 4 if design permits.]]
|}
 
[[Category: modeling]]

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