Hazen-Williams Hydraulic Grade Equation

This hydraulic grade formula is used in Hazen-Williams equations and the coefficient formula.

 

Hazen-Williams Hydraulic Grade Equation formulas

\(\large{ m =   \left(     \frac {v} { 1.318\;C \;  r_h^{0.63} } \right)   ^{\frac {1}{0.54} }  }\)
\(\large{ m =   \left(     \frac {Q} { 0.285\;C  \;   d^{2.63} } \right)   ^{\frac {1}{0.54} }  }\)

Where:

\(\large{ m }\) = hydraulic grade line slope

\(\large{ Q }\) = flow rate

\(\large{ C }\) = Hazen-Williams coefficient

\(\large{ r_h }\) = hydraulic radius

\(\large{ d }\) = inside diameter of pipe

\(\large{ v }\) = mean flow velocity