coastal processes. objectives examine physical properties of waves examine behavioral changes of...
TRANSCRIPT
![Page 1: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/1.jpg)
Coastal Processes
![Page 2: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/2.jpg)
Objectives
• Examine Physical Properties of Waves• Examine behavioral changes of waves
approaching coast• Explain the role of waves in sediment erosion,
transportation and deposition• Discuss tides and their role in coastal erosion
and deposition• Discuss effects of storms and crustal
movement on coastal landscapes.
![Page 3: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/3.jpg)
Coastal Processes
• Shape the landscapes along the coast– Must understand processes shaping coast
• Impact humans– More and more people moving to coast– Coastal areas heavily developed
• Must learn to manage coastal areas• Knowledge of coastal processes is management key
![Page 4: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/4.jpg)
Waves
• Most important agent in shaping coastal landforms
• Size of waves depends on:– Velocity– Wind persistance– Fetch
Garrison, Oceanography An invitation to marine science
![Page 5: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/5.jpg)
Wave Properties• Height = vertical distance from crest to trough • Wavelength = horizontal distance between
successive crests or troughs• Wave period = time required for two successive
crests to pass a fixed point
![Page 6: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/6.jpg)
Motion in Deep Water Waves• Motion is orbital• Waves with orbital particle motion termed waves
of oscillation• Particle motion ceases at ½ wavelength
![Page 7: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/7.jpg)
Waves Against the Shore• Swells shoal as approach coastline
– Feel bottom at ½ wavelength– Wavelength decreases– Wave height increases– Wave particle motion becomes elliptical– Wave breaks– Swash and backwash move on beach
![Page 8: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/8.jpg)
Wave Refraction• Bending of waves as
they approach coastline– Part of wave in
shallow area slows
– Part of wave in deeper area continues with higher speed
• Results in longshore current
![Page 9: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/9.jpg)
Erosion of Coastal Headlands• Wave refraction
concentrates energy on headlands
• Sand accumulation occurs in lower energy bays
• Results in straightening of coastline
![Page 10: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/10.jpg)
Shore Zone Currents—Rip Currents• Rip Currents
– Strong narrow currents moving from beach to ocean
– May be identifiable through interruption of breakers and muddier sediment moving seaward
![Page 11: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/11.jpg)
Shore Zone Currents—Longshore Currents
• Currents moving along the coast set up by wave refraction
![Page 12: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/12.jpg)
Longshore Drift• The movement of sediment
along the shoreline by longshore currents
• Beach drift is movement of sediment on the beach – Swash moves sand at an
angle up beach – Backwash swash moves
sand down the beach• Groins and other structures
used to interrupt drift and stabilize beaches
![Page 13: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/13.jpg)
Tides• High and low tides tend to
widen beaches• Tidal range is greatest in
estuaries, bays, and lagoons
• Erode and deposit sediment– Erosion occurs in
narrow rocky bays with great tidal ranges
– Where currents slow down deposition takes place
![Page 14: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/14.jpg)
Tides
![Page 15: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/15.jpg)
Storms
• May modify coastal areas in short period• Storm surges plus low atmospheric pressure
result in increased sea level– Wave aggressively attack coastal features– High tides aggravate conditions
![Page 16: Coastal Processes. Objectives Examine Physical Properties of Waves Examine behavioral changes of waves approaching coast Explain the role of waves in](https://reader035.vdocuments.mx/reader035/viewer/2022081400/551c0f3f550346ad4f8b5317/html5/thumbnails/16.jpg)
Crustal Movements
• Influence development of coastal features• Tectonic activity leads mostly to raising and
erosion of coast– California, Oregon, & Washington are examples
• Some coastal areas are sinking due to accumulation of sediment– Texas and Louisiana are examples