Wave Processes and Related Shoreline Processes

1
Wave Processes and Related Shoreline Processes

• The Deposition and Erosion of the Costal Zone

2
Shoreline Equilibrium

• Steady Time
• Beaches reflect average weather and seasonal
  changes, and their effect on the coast line.
• Graded Time
• Beaches are continually and slowly changing
  toward equilibrium
• Dynamic Equilibrium
• Changes that occur during major eustatic sea
  level change

3
Wave Processes

• Wave processes dominate shoreline landforms
• Sediment Transport
• Deposition and Erosion
• Affect in both steady and graded time

4
Wave Formation

• Form primarily from wind energy
• Empirically relative to wave period and height
• Form at different heights
• Wave interference
• Wave enhancement
• 20m to 34m

5
Wave Dispersion

• Migrate from source according to period
• Empirically related to wave velocity
• Wave steepness
• Length to Height ratio
• Swell
• Low steepness
• Creates waves of oscillation

6
Wave Oscillation

• Picture showing the action of wave oscillation
• http//images.google.com/imgres?imgurlhttp//uplo
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7
Wave Movement

• Picture showing the action of a wave
• http//www.ndu.edu/inss/books/Books20-201998/Mil
  itary20Geography20March2098/Fig9.jpeg

8
Swell

• Separate from Origin
• Creates grouping
• Travel long distances
• Thousands of Kilometers
• Negligible lose of energy
• Until coastal interaction

9
Costal Affect on Wave Behavior

• http//www.tulane.edu/geol113/COASTAL-PROCESSES-1
  a_files/image006.jpg
• Grid showing wave diffraction
• http//images.google.com/imgres?imgurlhttp//www.
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• Primary influences
• Ocean floor topography
• Shoreline irregularities
• Refraction
• Diffraction

10
Shoaling

• Interaction between the wave and the ocean bed
• Occurs when wave height and length are properly
  proportioned
• Oscillatory waves transform to waves of
  translation

11
Waves of Translation

• Picture showing the transition to waves of
  translation
• http//images.google.com/imgres?imgurlhttp//uplo
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Picture showing waves of translation entering the
beach
12
Wave Breaks

• Occur when oscillatory waves become unstable
• Steepness
• Period remains constant
• Rate and intensity depend on bottom topography
• 3 common types
• Spilling
• Plunging
• Surging

13
Swash Zone

• Where the water meets the shoreline
• Laminar flow
• Picture showing swash and backwash
• http//www.ux1.eiu.edu/cfjps/1300/coasts.html

14
Surf Beat

• Separate swell origins hit the coastline
  simultaneously
• Gradually build to a maximum height
• Gradually reduce to a minimum height
• Repeat
• Periodicity remains intact
• Considerable affect on near-shore currents and
  prevailing water level.

15
Tsunamis

• Created by displacement of water
• Earthquake (6.5 Richter)
• Submarine landslides
• Slumping
• Volcanic eruptions