1. Barrier Islands are Geologically Temporary

3. Chandeleur Islands Before (above) and after (below) Hurricane Katrina

4. 10) Sea Cliff Erosion Headlands erode from wave action Creates caves, arches, sea stacks

5. Sea Cave

6. Arches

7. Sea Stacks

10. Sea Cliff Erosion

11. Coastal Erosion

15. 1) Hurricanes and Coastal Erosion

16. Ivan: 2004 Dennis: 2005

17. Charley: 2004

18. Rita: 2005

20. Ivan: 2004

21. Katrina: 2005

22. Sea Cliff Erosion

24. Coastal erosion rates:Cape Cod, Massachusetts Average 0.5 ft/yr, 50 ft/century Not constant 15 feet in 5 years, then stable for 40 yrs Leads to false sense of security Erosion is episodic, not gradual

25. Local Erosion Rates Vary Depends on geology Storm frequency Louisiana: Several meters/year Rocky coasts: a few cm/yr Erosion is episodic, not gradual

26. Factors Leading to Erosion Depends on geology Storm frequency Wave height Tidal range Sea-level changes

27. Preventing Beach Erosion Structural: Sea walls and groins Non-structural: adding sand, land-use planning

28. Preventing Beach Erosion