1. The Restless Ocean

2. WARM UP /3/14
The Gulf stream is a warm ocean current, it flows toward _________.
What causes the deflection (bending) of ocean currents?
Weathering _______ when surface area increases.

3. Beaches and Shoreline Processes
Beaches are composed of whatever material is available
Some beaches have a significant biological component
Material does not stay in one place

4. Wave forces

5. Wave Forces

6. Wave forces Along the shoreline, waves are constantly:
Eroding – breaking stuff down
Transporting – moving it
Depositing – putting it down somewhere

7. How?
Wave impact: Waves hitting the shoreline creates a lot of erosion!

8. How else?
Abrasion: sawing/grinding of rock fragments in water

9. Beaches and Shoreline Processes
Wave refraction
Bending of a wave
Wave arrives more parallel to shore
Results of wave refraction
Wave energy is concentrated against the sides and ends of the headland
Wave erosion straightens an irregular shoreline

10. Wave Refraction Along an Irregular Coastline
Most of the energy from waves is here
WEAK energy!
Figure 10.12

11. Beaches and Shoreline Processes
Longshore transport
Beach drift—Sediment moves in a zigzag pattern along the beach face
Longshore current
Flows parallel to the shore
Moves substantially more sediment than beach drift

12. Beach Drift and Longshore Currents
END here
START here
Figure 10.13

13. Shoreline Features Erosional features Wave-cut cliff Wave-cut platform
Cutting action of surf against the base of coastal land
Wave-cut platform
Left behind by a receding cliff
Sea arch
Next slide
Sea stack
Next next slide

14. Sea Arch – happens at the headland (when two caves unite)
Figure 10.18

15. Sea Stack – an isolated remnant of a sea arch

16. Shoreline Features Depositional features
Spit —A ridge of sand extending from the land into the mouth of an adjacent bay with an end that often hooks landward
Baymouth bar —A sand bar that completely crosses a bay
Tombolo—A ridge of sand that connects an island to the mainland

17. Aerial View of a Spit and Baymouth Bar Along the Massachusetts Coastline
Figure 10.16

18. Spit
Figure 10.18

19. Baymouth Bar

20. Tombolo
Figure 10.18

21. Shoreline Features One more depositional feature! Barrier islands
Parallel to the coast

22. What is this?
Where is this?

23. Stabilizing the Shore Responses to erosion problems
Building structures
Types of structures
Groins —Barriers built at a right angle to the beach that are designed to trap sand
Breakwaters—Barriers built offshore and parallel to the coast to protect boats from breaking waves
Seawalls – walls along the coast to absorb the impact of waves

24. Bird’s eye view of a groin

26. In Hilo, HI….

27. Stabilizing the Shore Responses to erosion problems Alternatives
Beach nourishment by adding sand to the beach system

28. Miami Beach Before Beach Nourishment
Figure 10.22

29. Miami Beach After Beach Nourishment
Figure 10.22

30. Let’s see what you got out of this!

31. Waves do what along a shoreline?
Erode
Transport
Deposit
All of the above
Answer: 4

32. What is an isolated remnant of a sea arch?
Sea Stack!

33. The cutting and grinding of rock in water is called:
Wave impact
Abrasion
Refraction
Grindaction
Answer: 2

34. Longshore currents move in what direction in relation to the shore?
Diagonal
Parallel
In all directions
Answer: 2

35. If energy is low, would you have deposition or erosion?

36. If energy is high, would you have erosion or deposition?

37. What is an example of an erosional feature?
Wave-cut cliffs
Platforms
Sea Arches
Sea Stacks

38. What is an example of a depositional feature?
Spits
Baymouth bar
Tombolo
Barrier Island

39. What are some ways of protecting the shoreline from erosion?
Groins
Breakwaters
Seawalls

40. What is another way of protecting the coastline from erosion?
Beach Nourishment

41. So how did ya do? Out of 10!

42. Compare and Contrast Feature Caused by erosion Caused by deposition
Formed by fast moving waves
formed by slow moving waves
Picture
Sea arch
Spit
Baymouth bar
Tombolo
Wave-cut cliff
Sea stack
Barrier islands

45. Study Guide questions you should be able to answer
2,3,8,10-14, 16, 18, 18, 22-32, 34,35,39
Omit #6