All policy and standards in this document have been superseded by the FEMA Policy for Flood Risk Analysis and Mapping.
However, the document contains useful guidance to support implementation of the new standards.
Guidelines and Specifications for Flood Hazard Mapping Partners [February 2007]
D.2.14 Notation
Symbol Description
Units
Typical Units
English SI
A Equilibrium beach profile coefficient L.
ft.
m.
B Berm height L ft m
C Wave phase velocity or celerity L/T ft/s m/s
GC Wave group velocity L/T ft/s m/s
Ck Sample kurtosis ------
Cp Plant drag coefficient -----Cs
Sample skewness ------
C0 Deepwater wave celerity, gT/2p
L/T ft/s /s m
D Quarrystone diameter L ft m
D50
Dune height
Size of 50 percentile of sediment th
L
L
ft
mm
m
mm
hd bermDepth over L ft m
E Wave energy LF/L ft-lb/ft m/m N-
Crest elevation of structure L ft m
HotSpotE Extra profile lowering at a hot spot L ft m
Ej e juncture elevationBeach-dun L ft m
jMLWP E Beach-dune juncture elevation for the L ft m
MLWP
jStormE Beach dune juncture elevation during L ft m
a storm
TE Total still water elevation L ft m
e Base of natural logarithms (=2.718) ------
F unctionCumulative probability f ------
Fc Freeboard L ft m
F'
eeboardDimensionless fr ------
FH, FT, Fgamma, Static setup coefficients in DIM ------
Fslope model
nF Discrete spectral frequency 1/T hz hz
FR Wind wave runup coefficient ------
f Wave frequency 1/T hz hz
Darcy-Weisbach resistance ------
coefficient
Probability density function ------
fe Coriolis coefficient 1/T 1/S 1/S
fp Spectral peak frequency, 1/Tp 1/T hz hz
GH,GT, Ggamma, Dynamic setup coefficients in DIM ------
Gslope model
G0 Normalizing function for directional ------
spectrum spreading function
All policy and standards in this document have been superseded by the FEMA Policy for Flood Risk Analysis and Mapping.
D.2.14-1 Section D.2.14
Guidelines and Specifications for Flood Hazard Mapping Partners [February 2007]
Typical Units
Sym bol Description
Units English SI
G(.)
G(f,.)
g
H
Ho '
Hb
Hm0Ho
Hs
Hx
h*
h
hb
hc
hm
ho
Ks
Ks(fn)
Kr(fn, .o,n,m)
k
L
LL
Lberm
Lom
L0
M(n)
m
mn
.
Directional spectrum spr eading
function
Directional spreading function
Gravitational acceleration
Wave height
Unrefracted deep water wave height
Breaking wave height
Spectral significant wave height
Deep water wave height
Significant wave height
Wave height at x location in surf
zone
Wave structure parameter
Water depth
Breaker depth
Depth over crest
Height of the land barrier
Depth over crest
Shoaling coefficient
Spectral shoaling coefficient
Spectral refraction coefficient
Wave number, 2p/L
Bluff erosion parameter
Likelihood
Log-likelihood
Berm width
Spectral deep water wave length
Deep water wave length, gT2/2p
Number of direction components in
spectrum at fn
Beach slope (rise/run)
nth moment of spectral density,
f2
f nS ( f )df
.
f1
Degrees of freedom of a chi-squared
distribution
Number of wav es
L/T2
L
L
L
L
L
L
L
L
L
L
L
L
rad/T
L
L
L
L/L
L2/Tn
ft/s2
ft
ft
ft
ft
ft
Ft
ft
ft
ft
ft
ft
ft
rad/ft
ft
ft
ft
ft2/sn
m/s2
m
m
m
m
m
m
m
m
m
m
m
m
rad/m
m
m
m
m2/sn
All policy and standards in this document have been superseded by the FEMA Policy for Flood Risk Analysis and Mapping.
D.2.14-2 Section D.2.14
Guidelines and Specifications for Flood Hazard Mapping Partners [February 2007]
Typical Units
Sym bol Description
Units English SI
P
Q
q
R
Riuc
Rm
RTotal
R2%
R8
R8HotSpot
R8storm
r
S
Sc
S(f)
S(f,.)
S0 (fn, .o,n,m)
Sns (fn, .o,n,m)
s
S(f)
T
TD
Tp
Ts
t
Vc
Vf
Average porosity of rubble structure
cover layer
Precipitation rate
Probability
Dimensi onless overtopping
Mean overtopping rate per unit
length
Total wave runup
Spearman statistic
Incident wind wave runup
Reduced recession due to storm
duration
Total runup (static setup plus
dynamic setup plus incident wave
runup.)
Runup exceeded by 2% of the runup
crest
Maximum potential profile recession
Potential recession at a hot spot
Potential recession for storm
Linear correlation coefficient
Water level change
Compressive streng th of bluff
material
Spectral density
Directional spectral density
Discrete directional spectrum in deep
water
Discrete directional spectrum in
nearshore
Sample standard deviation
Continuous spectrum
Wave period
Storm duration
Spectral peak period, 1/fp
Significant wave period
Time scale for beach profile response
TimeVelocity at crest
Fall velocity
L/T
L2/T
L
L
L
L
L
L
L
L
F/L2
L2-T2
2
L T/deg
L2-T2
L2-T2
2
LT
T
T
T
T
T
L/T
L/T
in./hr
ft2/s
ft
ft
ft
ft
ft
ft
ft
ft
lb/ft 2
ft2/hz
2
(ft /hz)/deg
ft2/hz
ft2/hz
2
ft /hz
s
hr
s
S
s
ft/s
ft/s
mm/hr
m2/s
m
m
m
m
m
m
m
m
N/m2
m2/hz
(m2/hz)/deg
m2/hz
m2/hz
2
m /hz
s
hr
s
S
s
m/s
m/s
All policy and standards in this document have been superseded by the FEMA Policy for Flood Risk Analysis and Mapping.
D.2.14-3 Section D.2.14
Guidelines and Specifications for Flood Hazard Mapping Partners [February 2007]
Typical Units
Sym bol Description
Units English SI
Vmax Maximum overtopping volume per L2/wave ft2/wave m2/wave
wave per unit length
v Horizontal (y) component of local L/T ft/s m/s
fluid velocity (water particle
velocity) L/T ft/s m/s
W Windspeed L/T mi/hr m/s
Wb Surf zone width to breaker line L ft m
Wc Wind stress coefficient term L/T mph kph
Wx x component of windspeed L/T mi/hr m/s
Wy y component of windspeed L/T mi/hr m/s
X Accumulated bluff to erosion L ft m
Sample mean ------
x
x,y,z Right-handed Cartesian coordinates L ft m
yG,inner Seaward extent of overtopping L ft m
yG,outer Landward extent of overtopping L ft m
y0 Cross-shore location of structure L ft m
crest
zc Structure crest elevation L ft m
zG Elevation behind crest L ft m
( )b Term evaluated at the breaker line ------
( )o Term evaluated in deep water ------
tan a
Structure slope ------
a
Storm duration recession reduction ------
factor
JONSWAP Spectrum term L2T ft2/hz m2/hz
ac Structure crest slope ------
ß
Storm profile respon se coefficient ------
Wave angle at structure deg deg deg
.
Specific gravity of a fluid F/L3 lb/ft3 N/m3
Peak enhancement factor used in the ------
JONSWAP spectrum
.b Breaker depth index ------
Runup berm coefficient ------
.r .p .b .f, .ß
Runup reduction coefficients ------
.f Frequency increment 1/T hz hz
.R Potential excess runup L ft m
e
Energy dissipation rate F/LT lb/s-ft n/m-s
.
^
Dynamic or oscillating setup L ft m
.
Mean or static wave setup L ft m
.
b Static setdown at the breaker point L ft m
All policy and standards in this document have been superseded by the FEMA Policy for Flood Risk Analysis and Mapping.
D.2.14-4 Section D.2.14
Guidelines and Specifications for Flood Hazard Mapping Partners [February 2007]
Typical Units
Symbol Description
Units English SI
.
max
.
min
.
o
.(x,t)
.
2
.3
.4
.i
.rms
.
.
.main
.m
.m(f)
.
µ
.
.
.om
.0
p
.
.a
.fw
.s
.
f
tx,ty
s
Maximum static wave setup
Minimum static wave setup
Static setup at the shoreline
Displacement of water surface
relative to SWL
Mean square of water surface
fluctuations
Coefficient of skewness
Coefficient of kurtosis
Water surface displacement by
incident wave
rms value of free surface elevation
Overall mean wave direction
Direction of wave propagation
Main wave direction in a directional
spectrum
Discrete wave direction
Mean wave direction as a function of
frequency.
Breaker index
Wind stress factor
Population Mean
Spectral narrowness parameter
Surf similarity parameter or Iribarren
number
Spectral deep water .
Deep water .
Constant = 3.14159
Mass density of water
Mass density of air
Mass density of fresh water
Mass density of sediment
Rotational speed of the earth
Latitude
Wind stress
Population standard deviation
L
L
L
L
L2
L
L
deg
deg
deg
deg
deg
--
--
M/L3
M/L3
M/L3
M/L3
rad/T
deg
F/L2
L
ft
ft
ft
ft
ft2
ft
ft
deg
deg
deg
deg
deg
slug/ft3
slug/ft3
slug/ft3
slug/ft3
rad/S
deg
lb/ft2
ft
m
m
m
m
2
m
m
m
deg
deg
deg
deg
deg
kg/m3
kg/m3
kg/m3
kg/m3
rad/S
deg
N/m2
m
All policy and standards in this document have been superseded by the FEMA Policy for Flood Risk Analysis and Mapping.
D.2.14-5 Section D.2.14