Culvert Hydraulics Calculator (HDS-5)
Units
US (in, ft, cfs)
SI (mm, m, m³/s)
Inlet type
Conc., square edge w/ HW
Conc., groove end w/ HW
Conc., groove end projecting
CMP, headwall
CMP, mitered
CMP, projecting
Diameter, D
in
Length, L
ft
Slope, S
0
—
Manning's n
—
Flow, Q
cfs
Tailwater, TW
ft
HW (inlet)
—
ft
HW (outlet)
—
ft
Controls
—
—
Design HW
—
ft
$$ \tfrac{HW_i}{D} = c \left(\tfrac{Q}{A D^{0.5}}\right)^{\!2} + Y - 0.5 S_0 $$
via
PE-Calc — Culvert Hydraulics