1. — Robert Browning Hamilton (Brainyquote.com)20
Coastal Processes
and Terrain
“The sea heaves up, hangs loaded o'er the land, Breaks there, and buries its tumultuous strength. ”
— Robert Browning Hamilton (Brainyquote.com)

2. Coastal Processes and Terrain
The Impact of Waves and Currents on the Landscape
Coastal Processes
Coastal Landforms

3. The Impact of Waves and Currents on the Landscape
Coastal Processes
Erosion – by waves, mainly
Deposition – by currents, mainly
Rocky cliffs and headlands
Main erosional features
Beaches and sandbars
Main depositional features

4. Coastal Processes Erosion and Deposition Coast
Involves the transfer of energy from the atmosphere (wind) to the hydrosphere (ocean) and then to the lithosphere (land).
Kinetic energy transfer
Wind
Deposition
Erosion
Wind
Coast

5. Waves
Wave Motion and Wave Refraction
Tsunami
Animation
Definition – A disturbance in water caused by energy passing through it.
Wave terms: wavelength, wave crest and trough, swash
Fig. 20-2

6. Wave Refraction (see previous animation)
Fig. 20-5

7. Formation of Arches
Fig Headland erosion in Australia along the southern coast of the state of Victoria, read caption, pg 592.

8. Wave Erosion, see caption, pg 593
Hydraulic pounding and sea cliff erosion
Chemical action (some rocks are soluble in sea water)
Fig Formation of a Wave-Cut Notch

9. Wave Erosion Cliff face Former shore Notch Wave-cut platform Sea Level
Fig Formation of a Wave-Cut Notch

10. Tides Animation (Tides)
Significant erosion agents in narrow bays, margins of shallow seas, and straits.
Fig Bay of Fundy has the highest tidal range in the world. Tidal action created these pedestal rocks on the edge of the bay, read caption, pg 595.

11. Changes in Sea Level and Lake Level
Due to:
Tectonic uplift or sinking of landmass
Eustatic – increase or decrease in the volume of water in the oceans (Pleistocene glaciations). Also, global warming.
Fig Northern California coast is experiencing tectonic uplift.

12. Currents and Coastal Sediment Transport
Longshore Currents (see next slide and stabilization animation)
Wave refraction
Beach Drifting
Particle-by-particle transport of beach material
Figure 20-12

13. Fig. 20-13. Waves approaching the shore obliquely causes longshore currents and beach drifting.

14. Coastal Deposition Based on the sediment budget of a shore
Deposition mainly occurs when inputs from longshore current and wave action exceeds outputs from storm wave action.
E.g. large beaches and sand dunes
Fig
Fig One of the largest coastal dune accumulations is on the Oregon coast.

15. Coastal Landforms Depositional Landforms Beaches
Most widespread marine dispositional feature on land (mostly sand deposits)
Fig Components of the beach environment

16. Spit and related features
Spit: Linear strand of marine sediments attached to shore
Formation usually involves longshore current transport
Related features
Fig Types of spits and the longshore current.

17. Bay (3) Baymouth bar (2) Hook Land Simple spit Ocean
Idealized drawings of formation of spit and related features
Bay
(3) Baymouth bar
(2) Hook
Simple spit
Land
Ocean

18. Photographs of spits and related features
Fig Spit at Cape Henlopen, Delaware

19. Small island / sea stack
Tombolo formation
Land
Ocean
Small island / sea stack

20. Fig. 20-18. Tombolo and Mont Saint Michel on the northwest coast of France.

21. Barrier Islands (also, Fig 20-20, pg 602)
Coastal islands, parallel to the mainland shore
Complex origins
Pleistocene sediments washed toward mainland or longshore transport and spit segmentation
Lagoon formation
Landward side of barrier island, protected from large waves
Low energy environment, fine mud deposits (tidal flats)
Fig

22. Human Alteration of Coastal Sediment Budgets
Beach starvation (unintentionally shrinking beaches)
Dam construction on rivers reduces sediment discharge into oceans, starving nearby beaches of sand
Old debris dam in Santa Ynez Mountains, near Santa Barbara, CA (Richard A. Crooker photo)

23. Beach nourishment (re-building beaches)
Adding sand to beaches by dredging and pumping sand from off-shore
A slurry of sand and water is pumped on shore and the sand is spread onto the beach of Rehoboth Beach, DE (Richard A. Crooker photos) (overlay)

24. Animation (Coastal Stabilization Structures)
Beach preservation (maintaining beaches)
Build structures that modify longshore transport and wave action in order to keep sand on beaches
Jetties and groins (see personal pictures)
Fig

25. Shorelines of Submergence
Ria Shorelines (formed at the end of the last ice age)
Hilly or mountainous areas
flooded valleys become estuaries (long fingers of seawater projecting inland). Dams also create similar landforms, although these are technically not estuaries (see photos of Hoover Dam).
Fig , Chesapeake Bay. Read caption, pg 603.

26. Fjorded Coasts
Fjord – glacial trough that is cut so deep that it is inundated by the sea (after glacial melting)
Fig

27. Shorelines of Emergence
Wave-Cut Cliffs and Platforms (photo, pg 604)
Marine Terraces are uplifted landforms (captions, pg 605)
- Fig and 27.
Near Fort Ross, CA

28. Coral Coasts Coral Polyps
Reef-building creatures, in warm tropical waters
Fig

29. Fig , read caption

30. Sinking Islands Three types of reefs  Fringing  Barrier  Atoll
Sea Level
 Fringing
Sea Level
 Barrier
Sea Level
 Atoll

31. Fig. 20-32. Part of the fringing reef on the island of Moorea, French Polynesia.

32. Shallow-water Platforms
Australia’s Great Barrier Reef
Fig