1. AGENT C- Coastal Processes (wave action or ocean motion)
Must be viewed as a slide show!!!
AGENT C- Coastal Processes
(wave action or ocean motion)
Ms. Susinno

2. What is our barrier island?
Long, narrow islands of sand and/or gravel that are usually aligned parallel to the shore of some coasts.
What is our barrier island?

3. Montauk Point Lighthouse
Fire Island

4. Waves in the Sea
Most waves result from winds. A wave is described by its height, wavelength, period, and speed.
Trough
Crest
Wavelength
Height
Speed = Wavelength
Period

5.
½ wl
As a wave passes through water, the water particles move in a circular motion. Waves “feel” the bottom when water depth is half of wave’s wavelength.

6. Waves approach the shoreline at an angle (refraction- longshore current)
Swash, backwash, longshore currents, and rip currents move water and sediments on beaches.
WEST
Fire Island
EAST
Backwash
Swash
This is Sandy. He’s a grain of sand.
Longshore current
and transport of sand

7. If the waves are driven by the winds, and we live in the prevailing Southwesterlies, why does the longshore current go opposite on Long Island?
Wave
refraction
Meanwhile… in the Big Atlantic SW

8. Fetch- The length of open water over which wind blows steadily.
Period- The time it takes for one full wavelength to pass a given point
Waves affect the shoreline by eroding and depositing materials.

9. Where would Erosion take place?
Really do click on the link below. It is very helpful and I think Ant Man is narrating it.
Where would Erosion take place?
Deposition?

10. Shoreline Features Anything that is cliffy is an erosional (–) feature
Longshore current
Anything that is cliffy is an erosional (–) feature
Anything that is beachy or sandy is a depositional (+) feature. Can you find them here? You are allowed to call Mr. Tom Mr. Tombolo ONCE.
Sea cliff
Tombolo
Sea arch
Sea stack

11. Sandbars, spits, baymouth bars, hooks, lagoons, and barrier islands result from shoreline deposition.
Longshore current
Find erosional and depositional features.
Lagoon
Spit
Baymouth bar

12. Click once to see my friend “Sandy” and again to see how he is eroded and deposited.
Which coastal feature may result?

13. Jetties or Groins Rockaways Montauk Rockaways Montauk
ACTUAL GOOGLE EARTH IMAGE!!!!
Montauk
Know how to draw deposition and erosion in relation to a jetty.
Rockaways
Montauk
Jetties or Groins

14. If you never learn anything in this class… LEARN THIS!
and
Rip currents (undertow) most typically form at low spots or breaks in sandbars, and also near structures such as groins, jetties and piers.

15. On Long Island, South Shore beaches: Swim toward NY City so that the longshore current is at your back! KNOW HOW TO SPOT A RIP!
Don’t swim near jetties!

16. During a hurricane, waves get HUGE in the “armpit” because of refraction

17. See if you can name the features on the following slides
See if you can name the features on the following slides. Are they erosional or depositional features?

18. Sandy Hook, NJ
Spit

19. Indonesian island, Bali
sea arch

20. tombolo
Rip current
Remember, you can’t always see the rips. NEVER EVER EVER go swimming without a lifeguard on duty.

21. bay
headland
Orkney, Scotland
San Mateo County, California.

22. The end!