1. Shorelines and Shoreline Processes
Chapter 16

2. The Seafloor Main parts Other features Abyssal Plain
Continental Margin (active or passive)
Continental Rise
Continental Slope
Continental Shelf
Other features
Oceanic Ridges
Oceanic Trenches
Seamounts, Guyots, Reefs, Atolls

3. Shoreline Processes and Features
Waves
Nearshore Currents
Tides
Winds
Shoreline Sediment Budget (erosion, transport, deposition)
Storms (hurricanes, nor’easters)
Shoreline Features
Beaches
Dunes
Spits and Tombolos
Barrier Islands
Inlets
Inlet flood-tidal and Ebb-tidal deltas

4. Waves Wind-generated (frictional drag of one fluid on another)
Energy from the wind is transferred to the coastline.
Factors that affect wave size
Wind speed
Duration of wind
Fetch (distance wind blows over surface)
Slope of shoreline

5. Nearshore Currents Longshore currents (longshore drift)
Wave refraction
Rip currents

6. Tides Two high and two low tides per day. 50 minutes later each day.
Gravitational influence of Moon and, to a lesser degree, the Sun
Spring Tide: Moon and Sun in a line (higher than average)
Neap Tide: Moon and Sun at right angles (lower than average)

7. Wind and Dunes Storm winds Prevailing winds Seasonal winds
Winds push sand away
from the beach an form
large dunes.
Dunes can migrate if not
stabilized by vegetation.

8. Nearshore Sediment Budgets
Erosion, transportation and deposition
Balanced—supply of sediment balances erosion of beach
Positive—supply of sediment exceeds erosion of beach
Negative—supply of sediment cannot keep up with erosion of beach

9. Storms Large-scale change along the shoreline is caused by storms
Heavy storms
Hurricanes
Nor’easters

10. Beach
A deposit of unconsolidated sediment extending landward from low tide to high tide to a change in topography.
All parts of the beach adjust to the prevailing conditions of wave intensity and nearshore currents.

11. Erode sand from beach face Summer Low energy waves
Figure 16.15: Seasonal changes in beach profiles.
Winter
High energy waves
Erode sand from beach face
Summer
Low energy waves
Push sand back onto the beach face
Fig , p. 382

12. Barrier Islands
A barrier island is a collection of sand associated with a gently sloping continental shelf.
Open ocean features that occur throughout the world.
Form as a result of four factors
A rising sea level
A large sand supply
A gently sloping coastal plain
Sufficient wave energy to move sand
(From The North Carolina Shore and its Barrier Islands, Pilkey, et. al.,1998)