Presentation on theme: "Topic 19 Shoreline Engineering"— Presentation transcript:
1 Topic 19 Shoreline Engineering GEOL 2503Introduction to Oceanography
2 Responses to an Eroding Shoreline Hard StabilizationSeawalls, groins, breakwaters, etc.Soft StabilizationBeach replenishment, dune buildingRelocation or retreatMove back from eroding shoreline
3 Engineering Structures Shore PerpendicularGroins used to prevent erosion of sand by longshore transportJetties and breakwaters to prevent longshore transport of sand into ports and harborsShore ParallelSea walls and bulkheads to prevent wave erosion when real estate is threatenedAll these measures upset shoreline equilibrium and damage the natural system
4 Seawalls lead to loss of the recreational beach, and require continued maintenance
5 If an eroding beach meets a seawall, the recreational beach narrows
19 Relocation or Retreat Advantages Disadvantages Responds to sea-level risePreserves the beachSaves shoreline stabilization costsPreserves buildingsDisadvantagesPolitically difficultPotentially costlyLoss of land
24 Light and auxiliary buildings moved and new site designed to look like original
25 “The Beaches are Moving” Video Hosted by Dr. Orrin Pilkey, one of the world's leading authorities on barrier islands, this video discusses coastal processes and the impacts of human development and engineering. The video deals mostly with North Carolina's islands, but is applicable to all barrier coasts.As you watch the video, think about Georgia's islands and how the topics discussed might apply to our islands.The video can be accessed online at:
26 QuestionsThe following slides list several terms, names, and concepts with which you should be familiar after seeing the video. Think about these things as you watch the video. You should be able to answer each of these questions.
28 2. How does sand move on beaches: onshore, offshore, alongshore, including beach recovery after a storm?
29 3. What are tidal inlets and their associated flood tidal deltas and ebb tidal deltas? Address inlet movement: breathing, migrating, jumping.
30 4. Discuss original formation of barrier islands beginning 15,000 years ago and subsequent barrier island migration, including evidence of barrier island migration.
31 5. What does Dr. Pilkey mean when he says "Shoreline erosion is not island destruction, but island retreat?"
32 6. What should we have learned by the original patterns of island development as practiced by the American Indians and by the earliest settlers? How does this relate to Dr. Pilkey's statement that we should learn to "live with an island, not just on and island?"
33 7. Discuss the impact of development on natural barrier island environments.
34 8. Know what seawalls, jetties, and groins are 8. Know what seawalls, jetties, and groins are. Discuss the impact of hard shoreline stabilization on natural barrier island environments.
35 9. What is beach replenishment 9. What is beach replenishment? Discuss when this option would be appropriate.
36 10. What is relocation? Discuss when this option would be appropriate.