Hydraulic Design of Highway Culverts - DOT On-Line Publications

GLOSSARY (Cont.)
HV Velocity head = V 2 /2g, m (ft)
HW Depth from inlet invert to upstream total energy grade line, m (ft)
HWb Headwater depth above the bend section invert, m (ft)
HWC Headwater depth above the weir crest, m (ft)
HWd Design headwater depth, m (ft)
HWi Headwater depth above inlet control section invert, m (ft)
HWf Headwater depth above the culvert inlet face invert, m (ft)
Headwater depth above the culvert outlet invert, m (ft)
Total head of flow over embankment, m (ft) (Measured from roadway crest to up
stream surface level.)
HWt Depth from throat invert to upstream total energy grade line, m (ft)
I Rate of inflow into a storage basin, m 3 /s, (ft 3 /s)
Rainfall intensity, in/hr
k Flow constant for an orifice, Q = kah 0.5 , m 0.5 /s, (ft 0.5 /s)
ke Entrance loss coefficient
kt Correction factor for downstream submergence during roadway overtopping
K Coefficient for unsubmerged inlet control equation
Kb Dimensionless effective pressure term for bend section control
Kf Dimensionless effective pressure term for inlet face section control
K9 Dimensionless bar shape factor for calculating grate head losses
Kt Dimensionless effective pressure term for inlet throat control
L Actual culvert length, m (ft)
La Approximate length of culvert, including tapered inlet, but excluding wing
walls, m (ft)
Lr Width of roadway prism crest, m (ft)
L1, L2,
L3, L4
Dimensions relating to tapered inlets, m (ft)
M Exponent in unsubmerged inlet control equation
n Manning’s roughness coefficient
ñ Weighted Manning’s n value
N Number of barrels
0 Rate of outflow from a storage basin, m 3 /s, (ft 3 /s)
xv