1. The Coast: Beaches and Shoreline Processes
North Carolina

2. Landforms and terminology in coastal regions
Figure 10-1

3. Littoral Beach Profile

4. Movement of sand on the beach
Movement perpendicular (↕) to shoreline
Caused by breaking waves
Light wave activity moves sand up the beach face toward the berm
Heavy wave activity moves sand down the beach face to the longshore bars
Produces seasonal changes in the beach

5. Summertime and wintertime beach conditions
Summertime beach
Wintertime beach
Figure 10-2

6. Movement of sand on the beach
Movement parallel (↔) to shoreline
Caused by wave refraction (bending)
Each wave transports sand either upcoast or downcoast
Huge volumes of sand are moved within the surf zone
The beach resembles a “river of sand”

7. Longshore current and longshore drift
Longshore current = zigzag movement of water in the surf zone
Longshore drift = movement of sediment caused by longshore current
Figure 10-3b

8. Features of erosional shores
Headland
Wave-cut cliff
Sea cave
Sea arch
Sea stack
Marine terrace
Figure 10-4

9. Sea stack, Sea arch, Sea stump
Which Comes First????????

11. Features of depositional shores
Spit
Bay barrier
Tombolo
Barrier island
Delta
Figure 10-7

12. Barrier island, New Jersey

13. Barrier Islands North Carolina

14. Formation of barrier islands
Sea level rose after the last Ice Age
Caused barrier islands to roll toward shore like a tractor’s tread
Figure 10-10

15. Barrier islands serve two main functions
Barrier islands serve two main functions. First, they protect the coastlines from severe storm damage. Second, they harbor several habitats that are refuges for wildlife.
Fantastic and diverse ecosystems

18. Changes in sea level Sea level has changed throughout time
Tectonic and isostatic movements are localized and change the level of the land
Eustatic changes cause sea level to rise or fall worldwide and are produced by:
Changes in seawater volume
Changes in ocean basin capacity

19. Sea level has risen since the last Ice Age
Sea level was 120 meters (400 feet) lower during the last Ice Age
About 18,000 years ago, sea level began to rise as the glacial ice melted
Figure 10-14

20. U.S. coastal erosion and deposition
Figure 10-16

21. Types of hard stabilization
Hard stabilization perpendicular to the coast within the surf zone:
Jetties—protect harbor entrances
Groins—designed to trap sand
Hard stabilization parallel to the coast:
Breakwaters—built beyond the surf zone
Seawalls—built to armor the coast

22. Jetties and Groins Jetties are always in pairs
Groins can be singular or many (groin field)
Both trap sand upstream and cause erosion downstream
Figure 10-21

23. Breakwater at Santa Barbara Harbor, California
Provides a boat anchorage
Causes deposition in harbor and erosion downstream
Sand must be dredged regularly
Figure 10-22

24. Seawalls and beaches Seawalls are built to reduce erosion on beaches
Seawalls can destroy recreational beaches
Seawalls are costly and eventually fail
Figure 10-24

25. Alternatives to hard stabilization
Restrict the building of structures too close to the shore
Eliminate programs that encourage construction in unsafe locations
Relocate structures as erosion threatens them
Relocation of the Cape Hatteras lighthouse, North Carolina
Figure 10C

26. Rip Tides

27. View From Beach