Introduction to Coastal Engineering Harry C. Friebel, Ph.D., Harry C. Friebel, Ph.D., P.E. P.E. U.S. Army Corps of Engineers U.S. Army Corps of Engineers Philadelphia District Philadelphia District
Dec 09, 2015
Introduction to Coastal Engineering
Harry C. Friebel, Ph.D., Harry C. Friebel, Ph.D., P.E.P.E.
U.S. Army Corps of EngineersU.S. Army Corps of Engineers
Philadelphia DistrictPhiladelphia District
Objectives
To review for students:To review for students:1.1. Answer the question: What is Coastal Answer the question: What is Coastal
Engineering?Engineering?
2.2. Introduction to the vocabulary used by coastal Introduction to the vocabulary used by coastal scientists and engineers.scientists and engineers.
3.3. Explain some similarities and differences Explain some similarities and differences between the principal US coastal regions: between the principal US coastal regions: geology, storm risk, etc.geology, storm risk, etc.
4.4. Provide an overview of important physical Provide an overview of important physical processes in the coastal zone.processes in the coastal zone.
Intro Vocabulary Differences Coastal Processes Summary
References
ER 1105-2-0100, Planning Guidance ER 1105-2-0100, Planning Guidance NotebookNotebook
EM 1110-2-1100, Coastal Engineering EM 1110-2-1100, Coastal Engineering ManualManual
Shore Protection ManualShore Protection Manual. 1984. 4th ed., 2 . 1984. 4th ed., 2 Vol., U.S. Army Engineer Waterways Vol., U.S. Army Engineer Waterways Experiment Station, U.S. Government Experiment Station, U.S. Government Printing Office, Washington, D.C., Printing Office, Washington, D.C., 1,088p.1,088p.Intro Vocabulary Differences Coastal Processes
Summary
What is Coastal Engineering?
The USACE Coastal & Hydraulics Laboratory The USACE Coastal & Hydraulics Laboratory defines coastal engineering as: defines coastal engineering as: A branch of A branch of civil engineering that applies engineering civil engineering that applies engineering principles specifically to projects within the principles specifically to projects within the coastal zone (nearshore, estuary, marine, and coastal zone (nearshore, estuary, marine, and shoreline). shoreline).
The University of Delaware defines coastal The University of Delaware defines coastal engineering as: engineering as: Coastal engineering is the Coastal engineering is the study of the processes ongoing at the study of the processes ongoing at the shoreline and construction within the coastal shoreline and construction within the coastal zone. The field involves aspects of nearshore zone. The field involves aspects of nearshore oceanography, marine geology, and civil oceanography, marine geology, and civil engineering, often directed at combating engineering, often directed at combating erosion of coasts or providing navigational erosion of coasts or providing navigational access. access.
Intro Vocabulary Differences Coastal Processes Summary
Coastal Engineering Vocabulary
Water Wave - A deformation of the water’s surface.Water Wave - A deformation of the water’s surface.
Duration - length of time the Duration - length of time the wind blows.wind blows.
Wind speed – How fast the wind Wind speed – How fast the wind is blowing.is blowing.
Fetch – The horizontal distance Fetch – The horizontal distance (in direction of the wind) over (in direction of the wind) over which a wind blows.which a wind blows.
Figure from: http://geology.uprm.edu/Morelock/2_image/wavgenr.gif
Intro Vocabulary Differences Coastal Processes Summary
Crest - highest point on a wave.Crest - highest point on a wave.
Trough - lowest point on a wave.Trough - lowest point on a wave.
Wavelength - horizontal distance, Wavelength - horizontal distance, either between the crests or either between the crests or troughs of troughs of two consecutive waves.two consecutive waves.
Wave height - vertical distance Wave height - vertical distance between a wave's crest and between a wave's crest and the next the next trough.trough.
Wave period - time it takes for Wave period - time it takes for two consecutive crests or two consecutive crests or troughs to pass a stationary troughs to pass a stationary point.point.
Intro Vocabulary Differences Coastal Processes Summary
FACTFACT – Deep water particles do not move – Deep water particles do not move forward with water wave, but instead move in forward with water wave, but instead move in elliptical orbits. Waves are the forward elliptical orbits. Waves are the forward motion of energy, not water!motion of energy, not water!
Intro Vocabulary Differences Coastal Processes Summary
Example of water wave refraction at Allenhurst, Lock Arbour, Asbury Park, 1987.Example of water wave refraction at Allenhurst, Lock Arbour, Asbury Park, 1987.
Refraction
Intro Vocabulary Differences Coastal Processes Summary
Photo credit: Fjellanger Widerøe A.S.
Diffraction
Intro Vocabulary Differences Coastal Processes Summary
Gif credit: http://upload.wikimedia.org/wikipedia/commons/2/2d/Propagation_du_tsunami_en_profondeur_variable.gif.
Shoaling
Intro Vocabulary Differences Coastal Processes Summary
Photo credit:
http://pro.corbis.com.
Wave Breaking
Intro Vocabulary Differences Coastal Processes Summary
Photo credit: www.niwa.cri.nz/pubs/wa/ma/13-1/flooding
Wave Run-up
Intro Vocabulary Differences Coastal Processes Summary
Figure credit: www.coastal.er.usgs.gov
Wave Set-up
Intro Vocabulary Differences Coastal Processes Summary
Tides are caused by the gravitational Tides are caused by the gravitational force exerted by both the sun and moon force exerted by both the sun and moon and by the centrifugal force produced and by the centrifugal force produced by the revolution of the earth .by the revolution of the earth .
Normal water levels are tidally Normal water levels are tidally influenced.influenced.
TIDESTIDES
Intro Vocabulary Differences Coastal Processes Summary
Two bulges of water – one on the side Two bulges of water – one on the side of the earth facing the moon (and sun) of the earth facing the moon (and sun) and one on the opposite side.and one on the opposite side.
The bulges are stationary (relative to The bulges are stationary (relative to the Moon or sun), but the rotation of the Moon or sun), but the rotation of the earth about its polar axis causes the earth about its polar axis causes the bulges to move relative to the the bulges to move relative to the earth.earth.
TIDESTIDES
Intro Vocabulary Differences Coastal Processes Summary
SpringSpring tide is when tide is when the bulges due to the bulges due to the sun and moon the sun and moon are aligned (full are aligned (full moon and new moon and new moon). moon).
NeapNeap tide is when tide is when the sun and moon the sun and moon are in quadrature are in quadrature (quarter moon) (quarter moon) and thus the and thus the respective bulges respective bulges are not aligned.are not aligned.
TIDESTIDES
http://www.rise.org.au/info/Res/tidal/image001.jpg
Intro Vocabulary Differences Coastal Processes Summary
Diurnal Tide – one Diurnal Tide – one high and low per high and low per day.day.
Semi-diurnal Tide – Semi-diurnal Tide – two highs and two two highs and two lows per day.lows per day.
TIDESTIDES
Intro Vocabulary Differences Coastal Processes Summary
Do the Great Lakes experience tides?
http://glakesonline.nos.noaa.gov/monitor.html
Intro Vocabulary Differences Coastal Processes Summary
Similarities and differences between the principal US
coastal regions
Great Lakes
Atlantic Coast
Gulf Coast
Pacific Coast
Islands
Intro Vocabulary Differences Coastal Processes Summary
GeologyGeology
Atlantic/Atlantic/Gulf CoastGulf Coast
Pacific Pacific CoastCoast
IslandsIslands Great Great LakesLakes
TopographTopographyy
Flat Flat Coastal Coastal PlainPlain
Steep Steep MountainsMountains
VolcanicVolcanic ContinentaContinentall
BathymetrBathymetryy
Wide Wide Shallow Shallow ShelfShelf
Steep Steep OffshoreOffshore
Steep Steep OffshoreOffshore
ReefsReefs
Glacier Glacier modifiedmodified
Intro Vocabulary Differences Coastal Processes Summary
TopographyTopography
Laguna Laguna Beach, CA Beach, CA (1993)(1993)
St Joseph, MISt Joseph, MI
Westhampton, Westhampton, NY (1994)NY (1994)
Intro Vocabulary Differences Coastal Processes Summary
BathymetryBathymetry
Atlantic/Gulf Atlantic/Gulf CoastCoast
Lake ErieLake Erie
Pacific Pacific CoastCoast
Intro Vocabulary Differences Coastal Processes Summary
Storm RiskStorm Risk
Storm Storm HazardHazard
Atlantic/Atlantic/Gulf CoastGulf Coast
Pacific Pacific CoastCoast
IslandsIslands Great Great LakesLakes
TsunamiTsunami LowLow HighHigh HighHigh Very LowVery Low
HurricaneHurricane HighHigh Very LowVery Low Very LowVery Low Very LowVery Low
Intro Vocabulary Differences Coastal Processes Summary
Extra-tropical storm Extra-tropical storm Forms outside the tropics. Forms outside the tropics. Center of storm is colder than the Center of storm is colder than the
surrounding air. surrounding air. Has fronts. Has fronts. Strongest winds in the upper atmosphere.Strongest winds in the upper atmosphere.
Tropical storm:Tropical storm: Forms over a tropical ocean. Forms over a tropical ocean. Center of storm is warmer than the Center of storm is warmer than the
surrounding air. surrounding air. Has no fronts. Has no fronts. Strongest winds are near the Earth's Strongest winds are near the Earth's
surface.surface.
The Perfect StormThe Perfect Storm
Atlantic/Gulf Atlantic/Gulf CoastCoast
Intro Vocabulary Differences Coastal Processes Summary
Atlantic/Gulf Atlantic/Gulf CoastCoast
Intro Vocabulary Differences Coastal Processes Summary
Important Hurricane parameters
1.1. Central Pressure DeficitCentral Pressure Deficit
2.2. Radius of Maximum Wind SpeedRadius of Maximum Wind Speed
3.3. Forward Speed and Angle of Forward Speed and Angle of Approach (Quadrant)Approach (Quadrant)
4.4. Storm SurgeStorm Surge
5.5. Timing (Tide)Timing (Tide)
Intro Vocabulary Differences Coastal Processes Summary
1. Central Pressure Deficit
Hurricane Hurricane FloydFloyd
Figure courtesy http://cmn.dl.stevens-tech.edu/floyd/
Intro Vocabulary Differences Coastal Processes Summary
2. Radius of Maximum Wind Speed
Figure credit: www.wunderground.com
Intro Vocabulary Differences Coastal Processes Summary
3. Forward Speed and Angle of Approach
(Quadrant)
http://www2.sunysuffolk.edu/mandias/38hurricane/weather_history_38.html
1938 1938 HurricaneHurricane
Intro Vocabulary Differences Coastal Processes Summary
4. Storm Surge
Components:Components:
A.A. Pressure surgePressure surge
B.B. Wind surgeWind surge
C.C. Wave setupWave setup
http://coastal.er.usgs.gov/hurricanes/impact-scale/images/fig1LG.gif
Intro Vocabulary Differences Coastal Processes Summary
A. Pressure Surge
Pressure Surge - The light blue bulge represents Pressure Surge - The light blue bulge represents to water surface increase due to the reduced to water surface increase due to the reduced pressure in the eye of the storm.pressure in the eye of the storm.
ANALOGY - if several people sit around the edge of a waterbed, the center of the bed rises!ANALOGY - if several people sit around the edge of a waterbed, the center of the bed rises!
Intro Vocabulary Differences Coastal Processes Summary
B. Wind Surge
Surface stress (due to the wind) is balanced by a water surface Surface stress (due to the wind) is balanced by a water surface slope.slope.
ANALOGY - blowing on a hot cup of coffee.!ANALOGY - blowing on a hot cup of coffee.!
Wind surge becomes more pronounced in shallow water.Wind surge becomes more pronounced in shallow water.
Intro Vocabulary Differences Coastal Processes Summary
C. Wave Setup
This gradient of the This gradient of the SSxxxx radiation stress term is balanced by a slope radiation stress term is balanced by a slope of the water surface.of the water surface.
From linear wave theory, it can be shown that the mean water level From linear wave theory, it can be shown that the mean water level at the shoreline is elevated by more than 20% of the wave height.at the shoreline is elevated by more than 20% of the wave height.
Intro Vocabulary Differences Coastal Processes Summary
5. Timing (Tide) Assume Category 2 Hurricane or 8 foot surge
Compare peak at 18:00 July 1 vs. 01:00 July 2
Slide credit: Harley Winer
Intro Vocabulary Differences Coastal Processes Summary
TsunamisTsunamis is Japanese for “Big Wave.”is Japanese for “Big Wave.”
TsunamisTsunamis can be earthquake or landside can be earthquake or landside Induced.Induced.
TsunamisTsunamis considered long period or shallow considered long period or shallow water wave.water wave.
TsunamisTsunamis has small amplitude in deep ocean has small amplitude in deep ocean and shoals to great heights near shore.and shoals to great heights near shore.
Pacific CoastPacific Coast
Intro Vocabulary Differences Coastal Processes Summary
TsunamisTsunamis
Slide credit: Harley WinerSlide credit: Harley Winer
Intro Vocabulary Differences Coastal Processes Summary
TsunamisTsunamis
Slide credit: Harley WinerSlide credit: Harley Winer
Intro Vocabulary Differences Coastal Processes Summary
Coastal ProcessesCoastal Processes
Beach profiles
Littoral transport (cross-shore and longshore)
Sediment budgets
Accretion/Erosion
Intro Vocabulary Differences Coastal Processes Summary
Dune
Berm
MWL
Berm Crest
Beach Beach ProfileProfile
Slide credit: Randy Wise, NAP
Intro Vocabulary Differences Coastal Processes Summary
https://www.maine.gov/doc/nrimc/mgs/explore/hazards/erosion/shape.gif
Seasonal Profiles
Intro Vocabulary Differences Coastal Processes Summary
Depth of Closure
MHW
Sand Movement
Cross-shore transport
Slide credit: Randy Wise, NAP
Intro Vocabulary Differences Coastal Processes Summary
http://pubs.usgs.gov/circ/http://pubs.usgs.gov/circ/c1075/images/longshore.gifc1075/images/longshore.gif
Longshore transport
Intro Vocabulary Differences Coastal Processes Summary
Sediment Budgets
Generally waves come from Generally waves come from a predominate direction, so a predominate direction, so net transport will generally net transport will generally be in that directionbe in that direction
Gross transport is the sum Gross transport is the sum of the transport in the two of the transport in the two directions directions
Net transport is the Net transport is the difference between the difference between the transport in the two transport in the two directionsdirections
South = 100,000 c.y./year
Beach
North = 80,000 c.y./year
Gross Transport = ?
Net Transport = ?
Intro Vocabulary Differences Coastal Processes Summary
Sediment Budgets
It is important to identify It is important to identify rates of erosion when rates of erosion when building on the coast. A building on the coast. A beach can remain in beach can remain in equilibrium if the incoming equilibrium if the incoming sediment matches outgoing sediment matches outgoing sediment.sediment.
Empirical equations estimate Empirical equations estimate longshore transport.longshore transport.
Conservation of mass (check Conservation of mass (check book analogy) book analogy) – when outgoing is greater when outgoing is greater
than incoming - erosion than incoming - erosion – when incoming is greater when incoming is greater
than outgoing – accretionthan outgoing – accretion
Intro Vocabulary Differences Coastal Processes Summary
Accretion/Erosion
Sources (+)Sources (+)RiversRiversEroding headlandsEroding headlands
Sinks (-)Sinks (-)Sediment TrapsSediment TrapsInletsInletsOffshore DepthsOffshore DepthsLittoral Drift InterruptionsLittoral Drift InterruptionsSea Level RiseSea Level Rise
Intro Vocabulary Differences Coastal Processes Summary
Eroding Headland
River Delta
Sources (+)Sources (+)
www.truecolorearth.comwww.truecolorearth.com
Intro Vocabulary Differences Coastal Processes Summary
SinksTidal Inlets - Canaveral, Fl
19931950
Intro Vocabulary Differences Coastal Processes Summary
Sinks
www.nww.usace.army.mil/dmmp/report.htm
Offshore Depths Disrupt Littoral Drift
Sediment Trap
Intro Vocabulary Differences Coastal Processes Summary
Sinks
Implications of Sea Level Rise
Absolute Sea Level RiseAbsolute Sea Level Rise Relative Sea Level Rise – i.e. subsidence (land Relative Sea Level Rise – i.e. subsidence (land
sinking)sinking) Adjustment of Equilibrium Beach ProfileAdjustment of Equilibrium Beach Profile Sea level rise will be very significant in the Sea level rise will be very significant in the
evaluation of future with and future without project evaluation of future with and future without project conditions.conditions.
Intro Vocabulary Differences Coastal Processes Summary
Summary
In this session, we have:In this session, we have:
1.1. Defined Coastal EngineeringDefined Coastal Engineering
2.2. Introduced common vocabulary used by Introduced common vocabulary used by coastal scientists and engineers.coastal scientists and engineers.
3.3. Explained some of the similarities and Explained some of the similarities and differences between the principal US differences between the principal US coastal regions.coastal regions.
4.4. Provided an overview of the important Provided an overview of the important physical processes in the coastal zone.physical processes in the coastal zone.
Intro Vocabulary Differences Coastal Processes Summary