All policy and standards in this document have been superseded by the FEMA Policy for Flood Risk Analysis and Mapping.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 [November 2004]
D.4.12 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
CG 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 m/s
D Quarrystone diameter L ft m
D50
Dune height
Size of 50th percentile of sediment
L
L
ft
mm
m
mm
dh Depth over berm L ft m
E Wave energy LF/L ft-lb/ft N-m/m
Crest elevation of structure L ft m
EHotSpot Extra profile lowering at a hot spot L ft m
Ej Beach-dune juncture elevation L ft m
EjMLWP Beach-dune juncture elevation for the L ft m
MLWP
EjStorm Beach dune juncture elevation during L ft m
a storm
ET Total still water elevation L ft m
e Base of natural logarithms (=2.718) ------
F Cumulative probability function ------
Fc Freeboard L ft m
F'
Dimensionless freeboard ------
FH, FT, Fgamma, Static setup coefficients in DIM ------
Fslope model
Fn 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All policy and standards in this document have been superseded by the FEMA Policy for Flood Risk Analysis and Mapping.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.4.12-1 Section D.4.12
Guidelines and Specifications for Flood Hazard Mapping Partners [November 2004]
Typical Units
Symbol
Description
Units English SI
G(.)
G(f,.)
g
H
Ho '
Hb
Hm0
Ho
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 spreading
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,
f nS ( f )df
.
f2
1
f
Degrees of freedom of a chi-squared
distribution
Number of waves
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.4.12-2
Section D.4.12
Guidelines and Specifications for Flood Hazard Mapping Partners [November 2004]
mm/hr
2/s
N/m2
2/hz
(m2/hz)/deg
2/hz
2/hz
2/hz
All policy and standards in this document have been superseded by the FEMA Policy for Flood Risk Analysis and Mapping.
D.4.12-3 Section D.4.12
Symbol
Typical Units
Description
Units English SI
P Average porosity of rubble structure
cover layer ------
Precipitation rate L/T in./hr
Probability ------
Q Dimensionless overtopping ------
q Mean overtopping rate per unit L2/T ft2/s mlength
R Total wave runup L ft m
Spearman statistic ------
Riuc Incident wind wave runup L ft m
Rm Reduced recession due to storm L ft m
duration
RTotal Total runup (static setup plus ------
dynamic setup plus incident wave
runup.)
R2% Runup exceeded by 2% of the runup L ft m
crest
R8
Maximum potential profile recession L ft m
R8HotSpot Potential recession at a hot spot L ft m
R8storm Potential recession for storm L ft m
r Linear correlation coefficient
S Water level change L ft m
Sc Compressive strength of bluff F/L2 lb/ft2
material
S(f) Spectral density L2-T2 ft2/hz mS(f,.) Directional spectral density L2T/deg (ft2/hz)/deg
S0 (fn, .o,n,m) Discrete directional spectrum in deep L2-T2 ft2/hz mwater
Sns (fn, .o,n,m) Discrete directional spectrum in L2-T2 ft2/hz mnearshore
s Sample standard deviation ------
S(f) Continuous spectrum L2T ft2/hz mT Wave period T s s
TD Storm duration T hr hr
Tp Spectral peak period, 1/fp T s s
Ts Significant wave period T S S
Time scale for beach profile response ------
t Time T s s
Vc Velocity at crest L/T ft/s m/s
Vf Fall velocity L/T ft/s m/s
Guidelines and Specifications for Flood Hazard Mapping Partners [November 2004]
Symbol Description
Units
Typical 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 Wind speed 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 wind speed L/T mi/hr m/s
Wy y component of wind speed L/T mi/hr m/s
X Accumulated bluff to erosion L ft m
x Sample mean ------
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 response 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.4.12-4 Section D.4.12
Guidelines and Specifications for Flood Hazard Mapping Partners [November 2004]
Symbol Description
Units
Typical Units
English SI
.
max Maximum static wave setup L ft m
.
min Minimum static wave setup L ft m
.
o Static setup at the shoreline L ft m
.(x,t) Displacement of water surface L ft m
relative to SWL
.
2 Mean square of water surface L2 ft2 m2
fluctuations
.3 Coefficient of skewness
.4 Coefficient of kurtosis
.i Water surface displacement by L ft m
incident wave
.rms rms value of free surface elevation L ft m
.
Overall mean wave direction deg deg deg
.
Direction of wave propagation deg deg deg
.main Main wave direction in a directional deg deg deg
spectrum
.m Discrete wave direction deg deg deg
.m(f) Mean wave direction as a function of deg deg deg
frequency.
.
Breaker index
Wind stress factor
µ Population Mean
.
Spectral narrowness parameter
.
Surf similarity parameter or Iribarren
number
.om Spectral deep water .
.0 Deep water .
p
Constant = 3.14159
.
.a
.fw
.s
Mass density of water
Mass density of air
Mass density of fresh water
Mass density of sediment
M/L3
M/L3
M/L3
M/L3
slug/ft3
slug/ft3
slug/ft3
slug/ft3
kg/m3
kg/m3
kg/m3
kg/m3
.
Rotational speed of the earth rad/T rad/S rad/S
f
tx,ty
Latitude
Wind stress
deg
F/L2
deg
lb/ft2
deg
N/m2
s
Population standard deviation L ft m
All policy and standards in this document have been superseded by the FEMA Policy for Flood Risk Analysis and Mapping.
D.4.12-5 Section D.4.12