Deck 15: Waves Beaches and Coastal Erosion

Question 1

Which factor does NOT typically influence wave height?

A)atmospheric pressure
B)wind speed
C)fetch
D)amount of time the wind blows across water
E)interaction with other waves of different sizes and speeds

Answer 1

A

Question 2

Offshore barrier islands typically stand more than 4 meters higher than sea level.

Answer 2

False

Question 3

To be effective, beach replenishment sand should be dumped into the ocean as well as on the beach.

Answer 3

True

Question 4

What grows in the quiet waters of lagoons on the coastal side of barrier islands?

A)coral
B)clams
C)oysters
D)mussels
E)seaweed

Question 5

How can there be big waves at the coast when there is little or no wind?

A)Land must be sheltering your location from the wind.
B)The storm generating the waves is far offshore.
C)The waves take longer to dissipate than the wind.
D)The waves were caused by a large ship far offshore.
E)This cannot occur, because wind and waves always occur together.

Question 6

What is NOT a process that removes sand from the coast?

A)Wind blows sand inland to form dunes.
B)Rocks are pulverized into sand.
C)Hurricanes and other large storms carry sand offshore.
D)Rip currents carry sand into deeper water.
E)Sand is pulverized into finer grains and washed out with the surf.

Question 7

What is the path of waves in a storm?

A)Waves move inward toward the storm center.
B)Waves move outward from the storm center.
C)Waves move in a circular path around the storm center.
D)Waves take random paths as a storm moves through.
E)Waves move forward and back under the storm center.

Question 8

Why do waves not break in the open ocean?

A)Onshore winds drawn by rising warm air over land pull the tops of the waves to break.
B)Water in deep-water waves does not move forward with the wave; it moves in a circular motion.
C)Water in deep-water waves moves too fast to allow the wave to break.
D)Water in deep-water waves moves only up and down; it switches to forward and back in shallow water.
E)Waves only break in the deep ocean during tropical storms.

Question 9

Which is NOT a factor that contributes to wave energy?

A)wave height
B)wavelength
C)density of water
D)mass of moving water
E)angle of approach of the wave to the beach

Question 10

The amount of sand carried by longshore drift on parts of California's coast is much greater than that generally seen on the East Coast of the U.S.

Question 11

Why are ocean waves generally larger than those on lakes?

A)The wind direction varies less over lakes.
B)Winds are always stronger over the ocean.
C)Fetch is much longer in the ocean.
D)Ships generating the waves are bigger in the ocean than on lakes.
E)Tsunamis are generated in oceans but not in lakes.

Question 12

Shallower water, smaller waves, and coarser grains promote more gentle slopes offshore.

Question 13

Structures on a beach affect the location and formation of sand dunes.

Question 14

Natural revegetation of dunes using cuttings from nearby dunes is a quick and effective solution to dune erosion.

Question 15

By 2004, approximately one-fourth of the population of the continental United States lived in coastal counties.

Question 16

On shallow, gently sloping coastlines, such as those in much of the southeastern United States, the beach both onshore and offshore becomes steeper landward.

Question 17

What happens to a barrier island as sea level rises?

A)It erodes away and disappears.
B)It shifts seaward.
C)It shifts landward.
D)The wind picks up its sand to create dunes where the barrier island once was.
E)The impact of the sea level on a barrier island in negligible.

Question 18

Dumping fill material over an eroding bluff is not an effective way to slow erosion along cliff-bound coasts.

Question 19

Wavelength is the distance between a wave's crest and its trough.

Question 20

What happens to wave energy and erosion when riprap or seawalls are installed?

A)Waves striking the riprap are reflected back against the incoming waves to lessen their overall effect.
B)Wave height rises against the wall, and more erosion occurs at the base of the wall.
C)Seawalls do not influence wave energy or erosion; they only create separation between the sea and structures.
D)Waves lose their energy against riprap or seawalls, so erosion is prevented in that area.
E)Waves pulverize the riprap and seawalls, creating sand that helps maintain the beach.

Question 21

The slope of a beach is called its _______________.

Question 22

Which piece of evidence does NOT indicate that a barrier island has migrated landward?

A)A lighthouse that was built onshore is now well offshore.
B)Oyster shells that grew in the sheltered lagoon behind the barrier island are now found on the front beach.
C)Stumps of trees that grew along the lagoon are now found on the front beach.
D)Barrier island beaches are now more easily eroded than they were one hundred years ago.
E)Fine-grained lagoon sediments are layered beneath the sands of the barrier island.

Question 23

Why are inlets through barrier bars or barrier islands not closed by longshore drift of sand?

A)Such inlets are always the outlets for onshore rivers to reach the sea, so they flush the sand out.
B)Rapid flow of water back and forth through the inlet as tides rise and fall keeps it clear.
C)Longshore sand drifted into such inlets drops into deeper water, so it drifts out to sea.
D)Sand drifted into such inlets encounters brackish water from the inlet and dissolves.
E)Sand drifted into such inlets is carried into the lagoon by incoming waves.

Question 24

As waves pile up water onshore, the water may stream back offshore to create a(n) _______________.

Question 25

Which approach is NOT appropriate for addressing the high cost of beach replenishment?

A)trucking in sand from inland locations
B)moving homes to a safer distance from the coast
C)allowing the coast to erode land unimpeded
D)using crushed bottle glass instead of sand
E)using compacted garbage instead of sand

Question 26

The local rise in sea level during a storm is called the _______________.

Question 27

Waves approaching a steep coast encounter rocky points called _______________.

Question 28

Waves approaching shore at an angle create a(n) _______________ drift that essentially pushes a river of sand along the shore near the beach.

Question 29

Barriers built out into the surf to trap sand from migrating down a beach are called _______________.

Question 30

Why does the beach slope under water become steeper near shore?

A)The sand grains are finer near shore.
B)The bottom has to rise rapidly to merge with the sand of the barrier island.
C)Sand from the onshore part of the beach has to drop abruptly because offshore the sand is under water.
D)Waves in shallow water drag on the bottom, so they lose energy and need a steeper slope to move the sand.
E)The waves are bigger near shore.

Question 31

Beach mismanagement in New Jersey began in the mid-1880s when a(n) _______________ was built along more than half of the shoreline.

Question 32

What happens when boulders are piled in front of homes built on the beach?

A)The waves erode the sand below the boulders.
B)The boulders are washed out to sea by the waves.
C)The boulders protect the homes from the waves more or less permanently.
D)The waves push the boulders closer and closer to the homes.
E)The waves push the sand around the boulders inland to form dunes.

Question 33

Riprap walls that are used to maintain navigational channels for boat access into bays, lagoons, and marinas are called _______________.

Question 34

Why can non-native plantings on dunes be counterproductive in protecting beaches?

A)Non-native plants rarely survive in beach environments.
B)Non-native plants can require artificial watering, leading to a rise in the water table and gully formation.
C)Non-native plants can block the wind from moving the sand to and from the dunes.
D)Non-native plants can overtake the dunes, covering most of the sand, and require frequent cut-back.
E)Non-native plantings can change the soil acidity, making the sand more likely to blow away.

Question 35

Artificially moving large volumes of sand to the coast is called _______________.

Question 36

Which factor promotes a steeper slope on the active underwater part of the beach?

A)deeper water
B)shallower water
C)larger waves
D)finer grains
E)higher than average winds

Question 37

What is NOT a viable long-term solution to reducing the effects of beach erosion?

A)Learn to live with actively eroding beaches, rather than fighting natural processes.
B)Move buildings and roads back from the beach after storms.
C)Remove old dams on rivers feeding sand to the beach.
D)Stabilize sea cliffs, so they don't collapse onto beaches.
E)Move cliff-top houses back from the cliffs to let cliffs erode.

Question 38

The spraying of _______________ onto cliff walls is a temporary way to slow cliff loss and protect clifftop homes.

Question 39

Why does sea level rise during a near-shore storm?

A)Low atmospheric pressure of the storm permits sea level to rise.
B)The winds stir the water in circles, so it rises in the center.
C)High pressure in the storm forces the water up.
D)Waves cluster together, so the average sea level is higher.
E)The gravitational pull of the moon is stronger during a storm.

Question 40

Why does removing driftwood from a beach endanger the sea cliffs behind it?

A)Waves cannot get over the driftwood to get to the sea cliffs.
B)Waves have to be higher to reach over the driftwood to reach the sea cliffs.
C)Wave energy is reduced when waves move the driftwood.
D)Driftwood bouncing up and down on the beach pounds the sand grains together, making them more difficult to erode.
E)Driftwood breaks up the direct forward thrust of the waves, making them more erratic.

Question 41

In addition to sand moving along shore, how is beach sand permanently lost to the beach system?

Question 42

The equilibrium profile of a beach is linked to water depth and _______________.

Question 43

Explain the processes of wave refraction and longshore drift. What happens to sand as a result of these processes?

Question 44

What is beach hardening? What are three examples of techniques used in beach hardening? Why are these not good solutions to preventing erosion of sand on beaches?

Question 45

The _______________ of a wave is the time it takes for two crests to pass a point.

Question 46

Sand bars and barrier islands are most common along the _______________ and _______________ coasts of the United States.

Question 47

In areas prone to beach erosion, buildings are commonly elevated 4 m above the beach on _______________.

Question 48

What is a rip current? Describe the shoreline's shape as a result of rip currents, and the cause of the distinct shape.

Question 49

Waves are said to "feel bottom" when the water depth is less than approximately half the _______________.

Question 50

What is a shore profile? How is it created? Explain the concept of an equilibrium profile in regard to a shore profile.