Must be viewed as a slide show!!!
Ms. Susinno
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?
Waves in the Sea
Most waves result from winds. A wave is
described by its height, wavelength, period,
and speed.
Wavelength
Crest
Height
Trough
Speed = Wavelength
Period
Crest
http://www.classzone.com/books/earth_science/terc/content/visualizations/es1604/es1604page01.cfm?chapter_no=visualization
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.
Waves approach the shoreline at
an angle (refraction- longshore current)
http://oceanica.cofc.edu/an%20educator'sl%20guide%20to%20folly%20beach/guide/driftanimation.htm
Backwash
Swash, backwash, longshore currents, and
rip currents move water and sediments on
WEST
Fire Island
EAST
beaches.
Longshore current
and transport of sand
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?
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.
Where would Erosion take place?
Deposition?
http://www.wiley.com/college/strahler/0471480533/animations/ch19_animations/animation2.html
Shoreline Features
Sea cliff
Tombolo
Longshore current
Sea arch
Sea stack
Sandbars, spits, baymouth bars, hooks, lagoons,
and barrier islands result from shoreline
deposition.
Lagoon
Spit
Baymouth
bar
Longshore current
Click once to see my friend
“Sandy Grain” and again to
see how he is eroded and
deposited.
Which coastal
feature may result?
Rockaways
Montauk
Rockaways
Montauk
Jetties or
Groins
https://youtu.be/d8c7RJx5pBg
Rip currents (undertow) most
typically form at low spots or breaks
in sandbars, and also near structures
such as groins, jetties and piers.
On Long Island,
South Shore
beaches: Swim
toward NY City so
that the longshore
current is at your
back!
Don’t swim near jetties!
KNOW
HOW TO
SPOT A
RIP!
See if you can name
the features on the
following slides. Are
they erosional or
depositional
features?
Sandy Hook, NJ
Spit
Indonesian island, Bali
sea arch
tombolo
Rip current
bay
headland
San Mateo County, California.
Orkney, Scotland