# Curb Gutter Flow Rate

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

## Curb gutter Flow Rate formula

 $$\large{ Q = \frac { 0.56 } { n } \; m_c^{5/3} \; m_l^{1/2} \; q^{8/3} }$$

### Where:

 Units English Metric $$\large{ Q }$$ = gutter flow rate $$\large{\frac{ft^3}{sec}}$$ $$\large{\frac{m^3}{s}}$$ $$\large{ m_c }$$ = cross slope of pavement $$ft$$ $$m$$ $$\large{ q }$$ = flow width $$ft$$ $$m$$ $$\large{ m_l }$$ = longitudinal slope of pavement $$ft$$ $$m$$ $$\large{ n }$$ = Manning's roughness coefficient dimensionless

### Solve for:

 $$\large{ m_c = \frac { Qn } { 0.56 \; m_l^{1/2} \; Q^{8/3} } ^{3/5} }$$ $$\large{ q = \frac { Qn } { 0.56 \; m_c^{5/3} \; m_l^{1/2} } ^{3/8} }$$ $$\large{ m_l = \frac { Qn } { 0.56 \; m_c^{5/3} \; Q^{8/3} } ^2 }$$ $$\large{ n = \frac { 0.56 } { Q } \; m_c^{5/3} \; m_l^{1/2} \; Q^{8/3} }$$

Tags: Flow Equations