WATER LEVEL VARIATIONS, WAVE RUNUP OVERTOPPING

Wave Setup Wind Setup and Storm Surge Primary factors: • characteristics of storm • hydography of basin • initial state of system Other factors: Astronomical tides, atmospheric pressure

WAVE RUN-UP & OVERTOPPING

Wave Classification: Spectrum

Water Level Variations

•astronomical tides

• tsunamis

• seiches

• wave setup

• wind setup

• storm surge

•climatological variations

Deep water:

L o =200 km, H o=1 m,

T=17 min, C o=700 km/hr

Shallow water:

H=11 m, C=30km/hr

1957 Aleutian Tsunami @ O’aho

Seiching

Wave Setup

Wind Setup and Storm Surge

Primary factors:

• characteristics of storm

• hydography of basin

• initial state of system

Other factors:

Astronomical tides, atmospheric pressure

differences, earth’s rotation, rainfall, surface

waves, storm motion effects

Hurricane Isabel

wave height

Sept 18, 2003

FRF, Duck

Kitty Hawk

Hatteras Village

Main Items

• statistical properties of waves

• determine wind input for wave predictions

• calculate wind-generated waves

• understand various mechanisms for water level variations

Beach/Dune Processes

Structure Run-up/Overtopping

Wave Runup & Overtopping

Delft Report by Van Der Meer and

Janssen replaces pages 7.16-7.99.

R u2% = runup level exceeded by 2% of the waves

Wave Runup & Overtopping

revetment

design water level

op

op

S



2% max

u

s

R

H

 





Wave Runup Height

h= reduction factor for shallow foreshore

f = reduction factor for slope roughness

= reduction factor for wave angle

b = reduction factor for berm

tan

op

op

S



2% max

u

s

R

H

 





Reduction for Slope Roughness f

Reduction for Shallow Foreshore h

2

h

m h

s

h H

Influence of Berm b

Reduction factor: b = 1-r b (1-r dh), 0.6<b<1.0

Width factor: r b = 1 - taneq /tan

Location factor: r dh =0.5(d h /H s)2, 0<r dh<1

Reduction for Wave Angle 

1 0.0022

1 0.0033





runup

overtopping

Total Reduction tot

GIVEN: Waves with a height of H s =1.5 m and T=5 s

approaches the revetment depicted below.

FIND: The runup height R u2%.

Slopes:

tan 3/ 8.5

taneq3 /10.5

Overtopping Discharge

Breaking waves,

3

/ tan

b

op

Q

S





where:

0.06 exp 4.7

1

tan

op

c

b

S

R

R

H



 

(m3/m/s)

SWL

Rc

Non-breaking waves,

3

n

qQ gH

where:

1

c

n

s tot

R

R

H





SWL

h

Rc

Recommended Overtopping Standards

(backslope conditions)

• 0.1 l/s per m for sandy soils with a poor vegetation

• 1.0 l/s per m for clayey soil with good grass

• 10 l/s per m for a revetment construction

Correction for Wind (SPM)

'

c

s

f

h d

R

m s

m s







