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{{Plainlist|1=Where:
{{Plainlist|1=Where:
*''W<sub>T</sub>'' is the width of the inlet in m,
*''W<sub>T</sub>'' is the width of the inlet for complete capture (m),
*''Q'' is the flow perpendicular to the inlet in m<sup>3</sup>/s
*''Q'' is the design flow perpendicular to the inlet (m<sup>3</sup>/s)
*''S<sub>0</sub>'' is the longitudinal slope
*''S<sub>0</sub>'' is the longitudinal slope ratio
*''n'' is Manning's 'n' (between 0.012 and 0.016 for concrete, depending on surface treatment),
*''n'' is Manning's 'n' (between 0.012 and 0.016 for concrete, depending on surface treatment), and
*''S<sub>x</sub>'' is the cross slope}}
*''S<sub>x</sub>'' is the cross slope ratio}}
Where the intention is to capture only a proportion of the flow, the ratio of flow entering the curb inlet may be calculated::
Where the inlet width is constrained or the intention is to capture only a proportion of the flow, the ratio of flow entering the curb inlet may be calculated::
<math>R_c=1-\left ( 1-\frac{W}{W_T} \right )^{1.8}</math>
<math>R_c=1-\left ( 1-\frac{W}{W_T} \right )^{1.8}</math>
{{Plainlist|1=Where:
*''R<sub>c</sub>'' is the proportion of flow entering the curb cut, and
*''W'' is the available curb cut width (m)}}
==Example==
==Example==
A curb cut of 3 m is proposed as an inlet for an offline [[Bioretention|bioretention cell]] receiving runoff from an adjacent roadway. The gutter and the curb are made from smooth concrete with Manning's 'n' = 0.013. The x-slope is 3% and the longitudinal slope of the road is 2%. The design storm produces flow of 0.08 m<sup>3</sup>/s.
A curb cut of 3 m is proposed as an inlet for an offline [[Bioretention|bioretention cell]] receiving runoff from an adjacent roadway. The gutter and the curb are made from smooth concrete with Manning's 'n' = 0.013. The x-slope is 3% and the longitudinal slope of the road is 2%. The design storm produces flow of 0.08 m<sup>3</sup>/s.