Beach ErosionBeach Erosion

Part 1 Part 1

Natural Beach ErosionNatural Beach Erosion

•Blowing wind puts energy Blowing wind puts energy into wavesinto waves

1. How does energy get into 1. How does energy get into most ocean waves?most ocean waves?

A.A. SunlightSunlight

B.B. Density differencesDensity differences

C.C. WindWind

D.D. Hydrothermal ventsHydrothermal vents

When the waves hit the shore, When the waves hit the shore, they travel at an angle.they travel at an angle.

• The water hitting the beach can pick The water hitting the beach can pick up and move grains of sand.up and move grains of sand.

People, too!

Top View

2. What causes longshore 2. What causes longshore current?current?

A.A. Objects falling from spaceObjects falling from space

B.B. Waves hitting the shore at an angleWaves hitting the shore at an angle

C.C. Undersea earthquakesUndersea earthquakes

D.D. SunlightSunlight

3. What are barrier islands 3. What are barrier islands made up of?made up of?

A.A. CoralCoral

B.B. Volcanic rockVolcanic rock

C.C. SandSand

D.D. Sedimentary rockSedimentary rock

Rip currents, sometimes called “rip tides,” are dangerous. They pull swimmers under water and away from shore. If caught in a rip current, you may escape by swimming parallel to the shore and out of the current.

4. How can a swimmer escape 4. How can a swimmer escape a rip current?a rip current?

A.A. Swim parallel to the shoreSwim parallel to the shoreB.B. Swim out to sea with the currentSwim out to sea with the currentC.C. Swim against the current towards Swim against the current towards

shoreshoreD.D. Let the current carry you until you get Let the current carry you until you get

to shoreto shore

Rip currents Rip currents form as form as water flows water flows out out between between sand bars. sand bars. Notice the Notice the dark areas dark areas in the in the photosphotos

Ocean City, Maryland is a barrier

island. In 1933, a storm washed away

this part of the island, opening a

connection between the “bayside” and

“oceanside” parts of Ocean City. Before that event 2 parts of

the island were connected.

5. Ocean City, Maryland is a 5. Ocean City, Maryland is a barrier islandbarrier island

A.A. TrueTrue

B.B. FalseFalse

6. Ocean City, Maryland used 6. Ocean City, Maryland used to be 1 long island until a to be 1 long island until a storm broke it into two islandsstorm broke it into two islandsA.A. TrueTrue

B.B. FalseFalse

Natural barrier island Natural barrier island migrationmigration

7. It is natural for barrier 7. It is natural for barrier islands to move.islands to move.

A.A. TrueTrue

B.B. FalseFalse

Part 2Part 2

Human influencesHuman influences

JettiesJetties

• A jetty is a wall built out into the ocean. A jetty is a wall built out into the ocean. Jetties slow beach erosion by stopping Jetties slow beach erosion by stopping sand from being carried away.sand from being carried away.

8. How does a jetty slow beach 8. How does a jetty slow beach erosion?erosion?

a.a. Jetties stop waves from hitting the Jetties stop waves from hitting the beachbeach

b.b. Jetties add sand from the sea floor to Jetties add sand from the sea floor to the beachthe beach

c.c. Jetties stop sand from leaving the Jetties stop sand from leaving the beachbeach

d.d. Jetties block the waves from hitting Jetties block the waves from hitting the shorethe shore

These jetties, also called

groins, block the sand from moving down

the beach.

Note the

direction of drift.

What is the direction of longshore drift here?

AB

C

D

This is a jetty in Ocean City, New Jersey.

9. Which arrow shows the direction

of longshore drift?

AB

D

C

10. How many jetties do you count on this stretch of beach?

A.1

B.25

C.5-10

D.none

Jetties/Groins side viewJetties/Groins side view

Based on the images you’ve Based on the images you’ve seen, use your imagination to seen, use your imagination to

draw the side view on your draw the side view on your paper.paper.

This view of Baltimore’s Inner Harbor shows the

top of the seawall.

What would happen to Baltimore’s

streets and buildings if the

seawall were not there?

If you’ve shopped at the Inner Harbor,

you’ve been to these places!

seawall

Sea Wall side viewSea Wall side view

Based on the images you’ve Based on the images you’ve seen, use your imagination to seen, use your imagination to

draw the side view on your draw the side view on your paper.paper.

11. What are the walls facing 11. What are the walls facing the sea called?the sea called?A.A. JettiesJetties

B.B. SeawallsSeawalls

DuneDuness

Sand Dunes

Dunes Side View

Sand dunes and fences

12. What holds the sand in 12. What holds the sand in place at dunes?place at dunes?

A.A. FencesFences

B.B. Foot trafficFoot traffic

C.C. JettiesJetties

D.D. Plant rootsPlant roots

DredginDredging g and and pumpingpumping

This picture is of the land-side of the submerged pipe just as the

first load of sand is being pumped

through it.

This is a dredging ship

Dredging/Pumping top Dredging/Pumping top viewview

Based on the images you’ve Based on the images you’ve seen, use your imagination to seen, use your imagination to

draw the top view on your draw the top view on your paper.paper.

13. Which method shoots sand 13. Which method shoots sand from the sea floor onto the from the sea floor onto the beach?beach?A.A. JettiesJetties

B.B. Sand DunesSand Dunes

C.C. Sea WallsSea Walls

D.D. Dredging and PumpingDredging and Pumping