APPENDIX D

NOTATION

Drainage area, acres, total area of clear opening, or cross-sec-

A

tional area of flow, ft2.

Allowable headwater depth, ft.

AHW

Width, ft.

B

c

Coefficient.

Height of culvert barrel, ft.

D

Depth or thickness of grate, ft.

d

Critical depth, ft.

dc

Infiltration rate, in/hr.

F

g

Depth of water, ft.

H

Headloss due to friction, ft.

Hf

Headwater, ft.

Distance from culvert invert at the outlet to the control eleva-

hO

tion, ft.

Rainfall intensity, in/hr.

I

Hydraulic gradient.

i

K

Constant.

Coefficient.

Ke

k

Coefficient of permeability.

Length of slot or gross perimeter of grate opening, or length, ft.

L

Adjusted length, ft.

L1

Length of spiral, ft. (nonsuperelevated channel).

Ls

Length of spiral, ft. (superelevated channels).

Lt

Manning's roughness coefficient.

n

Discharge or peak rate of runoff, cfs.

Q

Hydraulic radius, ft.

R

Radius of curvature center line of channel, ft.

RC

s

Slope of energy gradient, ft/ft.

so

Slope of flow line, ft/ft.

Top width at water surface, ft.

T

Tailwater, ft.

v

Mean velocity of flow, ft/sec.

Discharge velocity in Darcy's law, ft/sec.

v

Depth of water, ft.

Y

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