1. Shorelines 1

2. Beaches and Coasts
The coastal zone and beaches along the continental margin are among the most dynamic geologic setting on earth
Human settlements are concentrated along the coast and most of the world’s population lives along the coast
Human activities along the coast oftentimes accelerate coastal erosion processes

3. Nearshore Circulation
Waves
Wave Refraction
Longshore Currents
Rip Currents 3

4. Wave Amplitude
Still Water Line
Wave Morphology

6. Wave Refraction
As waves approach the shore they will bend or refract because of their interaction with the seafloor
As the wave enters shallow water it will slow down as a consequence of friction or drag with the seafloor; however the wave portion in deep water still moves relatively faster
The wave front then turns or refracts

10. Longshore Drift
Sediment movement along the coastline is done by longshore currents and is termed longshore drift

12. Rip Currents
Rip currents are very strong currents that flow out to sea in the surf zone

15. THE COASTAL ZONE
or Dune
supratidal
intertidal
subtidal

16. Sand, Gravel, Pebble, Cobble Quartz Volcanic Carbonate
Sources of Sand
Sand, Gravel, Pebble, Cobble
Quartz
Volcanic
Carbonate

22. Nearshore Features Depositional Coasts Erosional Coasts Dunes
Beach Face, Berms
Beach sediment
Barrier Islands
Spits, baymouth bars, tombolos
Erosional Coasts
Headlands
Sea Cliffs, Sea Stacks, Sea Arches and Sea Caves
Wave-Cut marine Terraces 3

31. Coastal Development
Coastal development is increasingly important to the economic development of many countries
However coastal development often interferes with natural processes resulting in enhanced erosion
Engineering solutions to coastal erosion are often very costly and marginally successful

32. Miami , FL
Developed
Barrier Island

33. One in every three people on the planet now live within 100 kilometres of the sea
Two thirds of all the cities with over 2.5 million inhabitants are on the coast
In the US more than one-half the nation's population lives within 50 miles of the coastline, but coastal areas account for only 11 percent of the nation's land area.
In recent years, 40 percent of new commercial development and 46 percent of new residential development happened near the coast.

34. Coastal Erosion

48. North Carolina Coast
After Huriicane Impact

50. Beach Nourishment
Beach re-nourishment id one engineering solution to coastal erosion
It involves transfer of offshore sand or sand from quarries to the coast are a cost of millions of dollars
Many tourist beaches in the USA are there because of beach renourishment

51. Between 1995 and 2006, the Minerals Management Service provided over 23 million cubic yards of OCS sand for 17 coastal projects. These projects restored over 90 miles of the Nation’s coastline mainly in Florida, Maryland and Virginia

52. Central Boca Raton Beach Renourishment Project

54. Geologists are aware that the level of the ocean surface is not fixed, but instead
a dynamic feature of our planet. Sea-level during the Last Glacial Maximum
(LGM, 20,000 years ago) was m lower than it is at the present time.

55. Using digital elevation data, geologists can develop maps showing the continental margins
during episodes of lowered sea-level. The margin of the Gulf of Mexico and other parts of the
western Atlantic as they would have appeared 20,000 years ago during the sea-level
lowstand. Note that large areas of the continental shelf are exposed well above sea-level

56. Geologists can also model sea-level rise
Geologists can also model sea-level rise. Sea-level is 15 m higher than at present. Note the
dramatic change in the outline of the Gulf of Mexico as much of south Florida is inundated.
Also note that the Bahamas are completely submerged, and a narrow strip of land is all that
remains of Cuba.

58. Both Moon and Sun Cause Tides

60. DEFINITIONS Tidal day Tidal Period Tidal Range Daily inequality
24 hr 50 min
Time between successive phases of moon over a given point on the earth
Tidal Period
Time between two successive high or low tides
Tidal Range
Difference between highest and lowest tide levels
Daily inequality
Difference in height  between successive high or low tides

61. TIDES Periodic changes in sea level relative to land along a coast
Daily or Diurnal Tides
One high and one low tide each day
Semi-daily or Semidiurnal Tide
Two high and two low tides of approximate equal heights occur each day
Mixed Tide
Two high and two low tides of unequal heights (HHW, LHW, HLW, LLW)

64. TIDAL CURRENTS Horizontal water movement caused by tides
Tides are like Shallow water waves
Orbital motion of water is highly elliptical: can be assumed to be to and from motion
Flood tides when water moves in
Ebb tide when water moves back

66. The Bay of Fundy
Nova Scotia, Canada

67. In the Bay of Fundy the tidal range can be up to 16m

68. TIDAL BORE