This document discusses coastal erosion and the various natural processes that cause erosion along coastlines. It identifies different types of erosion including weathering, where rock breaks down but remains in place, and erosion, where broken down rock is transported. The key agents that drive coastal erosion are winds, waves, currents, tides, sea level change, and erosion itself. These forces can gradually shape coastlines over long periods and temporarily redistribute sediment. The document outlines different types of coastal landforms that form, like barrier islands and dunes, as well as human-built coastal structures used to combat erosion.

1. Coastal Erosion

2. Weathering vs. Erosion
• Weathering: Chemical or mechanical breaking down of
rock (but stays where it is)
• Erosion: The movement or transport or broken down
rock

3. Coastal Dynamics
• Processes that create and shape coastlines along the
ocean

4. Agents of Coastal Dynamics
• Coasts constantly change and in most areas moves inland
• Processes:
 Wind
 Waves
 Currents
 Tides
 Sea Level Change
 Erosion

5. Effects of Coastal Erosion
• Long term shaping of coasts
• Temporary redistribution of sediment

6. Longshore Current Erosion
• Energy from waves
dissipates down the
shoreline taking sediment
with it

7. Wave Action
1. Hydraulic Action –
incoming waves
compress air in cracks
in rock faces
2. Attrition – loose rocks
grind rock face and
break down
3. Corrosion – pH of ocean
dissolves rock materials
such as limestone

8. Effects due to Coastal Rock Density
• Harder rock areas weather
slower
• Softer areas (soil, etc.) erode
faster leaving unique
formations
• Over time these formations
even out by the erosion of
harder rock structures filling
in holes with sediment

9. Primary Factors Affecting Erosion
• Coastal make up (type of rock, density, etc.)
• Size of rock debris vs. wave energy
• Size of beach to dissipate energy
• Off shore structures (ex. sandbars)
• Seafloor configuration
• Rising sea levels

10. Secondary and Tertiary Factors
• Vegetation
• Slope
• Human Activity
• Coastal Management

11. Coastal Structures:
• Barrier Islands: large sediment
deposits the form between
ocean and the shoreline; always
changing (ex: OBX)

12. Coastal Structures:
• Dunes: Accumulated sand with stabilizing vegetation;
dissipate storm energy from reaching main coastline

13. Deltas
• Sediment formations where enough sediment from a river
can be deposited and not be carried away by ocean energy
due to wide continental shelves
Predicted due to sea level rise, flood
management, etc.

14. Coral Reefs
• Biologically/natural made areas in shallow waters that help
dissipate energy coming into shore

15. Human Built Coastline Structures
• Groins – perpendicular protrusions
protect from longshore current
erosion
• Jetties – similar to groins but
protect harbor entrances
• Breakwaters – run parallel to shores
to create artificial harbors
• Seawalls – block waves from
reaching and eroding shores