Hazen-Williams Flow through an Open Channel Equation

Hazen-Williams method is only valid for water flowing at ambient temperatures, the Darcy-Weisbach method should be used for other liquids or gases.  The Hazen-Williams Equation can be used for flow through an open channel or through a pressurized pipe.

 

Hazen-Williams flow through an open channel Equation formula
\(\large{ v = k \;C \; r_h^{0.63}\; m^{0.54}   }\)
Symbol	English	Metric
\(\large{ v }\) = mean flow velocity	\(\large{\frac{ft}{sec}}\)	\(\large{\frac{m}{s}}\)
\(\large{ k }\) = conversion factor	\(\large{ dimensionless }\)
\(\large{ C }\) = Hazen-Williams coefficient	\(\large{ dimensionless }\)
\(\large{ m }\) = hydraulic grade line slope	\(\large{ ft }\)	\(\large{ m }\)
\(\large{ r_h }\) = hydraulic radius	\(\large{ ft }\)	\(\large{ m }\)