X. The Coast: Beaches and Shoreline Processes (Chapter
10)
byAl Trujillo
Hard Stabilization: Jetties, Groins, and Breakwaters
Jetties: Always in pairs; built to protect a harbor entrance
Groins: Individual or many (if many = “groin field”); built to trap sand
Ex: Groin
• A groin has nothing to do with human anatomy…
• Why is a groin built?
• So that the beach is wide in front of your house!
Your house
Neighbor’s house
New groin
Ex: Breakwater
• A hard, rocky structure built parallel to shore and attached to the sea floor
• A few feet above sea level
• Designed to break waves and make quiet water behind
Curved breakwater, Greece
Case Study: Coastal Stabilization
Structures• Work together with your Success Team• Need: Case Study Handout (1 per team)• Rules:
Closed book (starting now!)Can use your notesRank each character’s ideaPut your rankings (#1, #2, #7) on the
boardBe prepared to discuss your choices
Case Study: Santa Monica, California
See Figure in Trujillo and Thurman textbook
After breakwater (1949)Before breakwater (1931)
Dredge
Breakwater destroyed by
waves in 1983
Case Study: Santa Monica, California
• Video: The Beach: A River of Sand (Part II)Shows Santa Barbara Harbor and the
problem its shore-connected breakwater created
Look for the Santa Monica breakwater (our Cast Study)
Good underwater footage of La Jolla Submarine Canyon
X. The Coast: Beaches and Shoreline Processes (Chapter
10)
byAl Trujillo
End
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