OCE1001 Ch. 10

What is the most obvious difference between summertime and wintertime beaches?

During summertime, there is much more sand on the beach.

Of the following statements about groins, which is/are true? Groins can be singular or many. Groins trap sand on their downstream side and cause erosion on their upstream side. Groins are built parallel to the coast beyond the surf zone. Groins add more sediment to the beach. Groins can be constructed out of large blocky rocky material (rip-rap) or of sturdy wood pilings.

Groins can be singular or many. Groins can be constructed out of large blocky rocky material (rip-rap) or of sturdy wood pilings.

Of the following statements about coastal regions and landforms, which is/are true? Most of the beach face is exposed during the lowest tides and covered during the highest tides. The beach face is the wet, sloping surface in the foreshore area. The area of a beach above the shoreline is often called the recreational beach. The berm is located in the backshore area. The berm is affected by storm waves but is typically dry and relatively flat. The nearshore is exposed during low tide each day.

Most of the beach face is exposed during the lowest tides and covered during the highest tides. The beach face is the wet, sloping surface in the foreshore area. The area of a beach above the shoreline is often called the recreational beach. The berm is located in the backshore area. The berm is affected by storm waves but is typically dry and relatively flat.

In the long term, what do beach drift and longshore current do? Move sediment perpendicular to the shoreline Move sediment parallel to the shoreline Move sediment up to the shoreline Move sediment away from the shoreline

Move sediment parallel to the shoreline

Of the following conditions, which help(s) form a well-developed delta? Small wave energy High rates of deposition Low rates of erosion A large-volume river High sediment load

Small wave energy High rates of deposition Low rates of erosion A large-volume river High sediment load

Southern California beaches would have more sand if __________. offshore structures were built to prevent waves from breaking onto the shore more seawalls were built to protect coastal bluffs winter storms were more severe, with larger waves the cobbles were removed from the beaches to make room for more sand dams were removed from streams flowing to the coast

dams were removed from streams flowing to the coast

Which feature of barrier islands provides evidence for a rise in sea level?

a peat outcrop

Beach joggers prefer to run on the __________.

beach face

If one were to walk from the ocean landward across a barrier island complex, in which order would one encounter the following environments?

beach, dune, barrier flat, high marsh, low marsh

Large deposits of sediment at the mouths of rivers are called:

deltas

Match the term with the appropriate phrase. barrier island depositional shore erosional shore

depositional shore

Alternatives to hard stabilization to protect coastlines from erosion include construction restrictions, relocation of structures, and construction of seawalls.

false

An increase in the spreading rate at a mid-ocean ridge will cause a decrease in sea level.

false

Seawalls are quite effective at controlling beach erosion.

false

Match the term with the appropriate phrase. longshore current colonized by grasses; very productive moves water from swash zone out to sea beyond the low-tide breakers flows parallel to shore within surf zone exposed at low tide and covered at high tide

flows parallel to shore within surf zone

The section of the coast that is exposed at low tide and submerged at high tide is called the:

foreshore

Match the term with the appropriate phrase. barrier flats beyond the low-tide breakers flows parallel to shore within surf zone moves water from swash zone out to sea found between dunes and high marsh exposed at low tide and covered at high tide

found between dunes and high marsh

In terms of erosion protection from wave action, seawalls:

lead to erosion of sediment on their seaward sides.

Eroded material is carried along coastlines from high wave-energy areas to:

low wave-energy areas.

The correct order of beach features as you move from the coast toward offshore is:

berm, beach face, longshore trough, longshore bar

The primary drawback of beach nourishment as a remedy for beach erosion is __________.

cost

Submerging shorelines might have all of the following characteristics except:

marine terraces

Match the term with the appropriate phrase. rip current exposed at low tide and covered at high tide flows parallel to shore within surf zone moves water from swash zone out to sea colonized by grasses; very productive beyond the low-tide breakers

moves water from swash zone out to sea

Most of the year, and most of the time, the movement of sediment and water (longshore current) along the California coast is from __________.

north to south

Along U.S. coasts, a drop in sea level can be noted at __________.

northern Maine

Nor'easters affect which area of the U.S. coastline during the fall and winter months?

northern atlantic coast

Conditions favorable for the existence of barrier islands occur in the United States __________.

on the Atlantic and Gulf coasts

Geologic evidence suggests that eustatic (global) sea level rises have been caused by __________. lateral movement on a transform plate boundary rapid seafloor spreading at divergent plate boundaries plate edges being dragged down by subduction at active continental margins isostatic rebound of land formerly occupied by continental glaciers vertical movement on a faulted continental margin

rapid seafloor spreading at divergent plate boundaries

You are an engineer assigned to design a solution to protect a historic landmark threatened by coastal erosion. What scenario would have the least impact on natural coastal processes and be the most cost effective?

relocate the structure

Narrow currents flowing across the surf zone toward the open ocean are called:

rip currents

Normally, beaches have the greatest amount of sand on the berm near the end of __________.

summer

Wave refraction is __________.

the bending of waves

A spit is a coastal feature of sand deposited in the direction of the longshore drift from shore toward deeper water into the mouth of a bay.

true

A summer recreational beach typically has more sediment on it than a winter recreational beach.

true

Eustatic changes in sea level refer to worldwide changes in the volume of seawater or in the volume of the ocean basins.

true

Sea caves and sea stacks are more likely to occur in an area with hard bedrock.

true

The Gulf coast of the United States is an example of a coast where tectonic subsidence occurs.

true

The coastal area affected by surf is referred to as the beach.

true

The velocity of the longshore current will be higher when wave heights are higher.

true

What is the longshore current? water forced by waves to move away from the shore water forced by longshore drift to move along the shore water forced by waves to move along the shore water forced by longshore drift to move away from the shore

water forced by waves to move along the shore

Of the following conditions, which result in the accumulation of sand on the berm, thereby making the berm wider? Saturated sand A beach dominated by backwash A beach dominated by swash Heavy wave activity (large waves) Light wave activity (small waves) Higher beach infiltration rates

A beach dominated by swash Light wave activity (small waves) Higher beach infiltration rates

Sediment is supplied to the coastal zone by:

All of the above are sources of sediment in the coastal zone.

A friend is considering purchasing a vacation home on a barrier island. Given what you've learned about the impact of waves on coastal landforms, what information and advice could you offer your friend? Select all that apply. Barrier islands are quite stationary due to the constant addition and removal of sand balancing out. Your friend should snap up the property quickly. Barrier islands tend to experience a good deal of sand erosion and deposition, and mitigating these effects is extremely difficult. Your friend would be wise to reconsider. A home on a barrier island is likely to take the full brunt of storm waves, making it a risky proposition. Your friend should think twice before purchasing. Because the barrier island is close to a larger landmass, it will be more protected from storms and waves. Your friend should definitely make the purchase.

Barrier islands tend to experience a good deal of sand erosion and deposition, and mitigating these effects is extremely difficult. Your friend would be wise to reconsider. A home on a barrier island is likely to take the full brunt of storm waves, making it a risky proposition. Your friend should think twice before purchasing.

Of the following statements about beach replenishment, which is/are true? Beach replenishment is expensive because of the huge volume of sand that is necessary to replenish a beach. Beach nourishment involves dumping sand on the beach to replace lost sand. Beach replenishment involves relocating structures such as houses to safer sites. Installing groins along the shore is a form of beach nourishment. Beach replenishment is also known as beach nourishment.

Beach replenishment is expensive because of the huge volume of sand that is necessary to replenish a beach. Beach nourishment involves dumping sand on the beach to replace lost sand. Beach replenishment is also known as beach nourishment.

What causes wave refraction? The part of a wave in shallow water slows down, causing the wave to bend and line up nearly parallel to the shore. Offshore sand bars that cause waves to break offshore. A wave strikes a shallowly submerged underwater object. Water piles up against a beach and then flows offshore against incoming waves. Winds that blow for a long time offshore create an area where waves are generated.

The part of a wave in shallow water slows down, causing the wave to bend and line up nearly parallel to the shore.

Of the following characteristics or features, which is/are associated with erosional shores? Wave-cut benches and marine terraces Rocky coasts Tectonic activity A large volume of sediment input A coastline with lots of rugged headlands

Wave-cut benches and marine terraces Rocky coasts Tectonic activity A coastline with lots of rugged headlands

Of the following statements about global sea level, which is/are true? When seawater warms, it thermally expands and occupies more volume, so global sea level rises. Sea level has risen about 120 meters (400 feet) in the past 18,000 years. When seawater cools, it contracts and occupies less volume, so global sea level is lowered. Sea level is affected by the amount of ice in polar ice caps on land. When the rate of sea floor spreading increases, global sea level is lowered.

When seawater warms, it thermally expands and occupies more volume, so global sea level rises. Sea level has risen about 120 meters (400 feet) in the past 18,000 years. When seawater cools, it contracts and occupies less volume, so global sea level is lowered. Sea level is affected by the amount of ice in polar ice caps on land.

Winter beaches: contain more sediment than summer beaches due to high-energy waves during the winter. are narrower than summer beaches due to high-energy waves during the winter. are wider than summer beaches due to low-energy waves during the winter. contain less sediment than summer beaches due to low-energy waves during the winter. have smaller offshore bars during the winter.

are narrower than summer beaches due to high-energy waves during the winter.

Which way would sediment move if NO beach drift existed? perpendicular to shore away from shore parallel to shore at an angle to shore

at an angle to shore

The area of the barrier island complex that would contain thickets and woodlands would be the:

barrier flat

You own a beachfront lot that has been experiencing erosion due to beach starvation. Your neighbor to the north (up-current) has the same problem, so he gets permission to build a groin just north of your property line. Your response would probably be to __________. do nothing, as the situation will stabilize with time and the sand will come back get permission to build a groin of your own near the southern boundary of your property armor your shoreline with a full-length seawall sue your neighbor for sand deprivation have sand trucked in to rebuild your beach

get permission to build a groin of your own near the southern boundary of your property

Southern California beaches in winter typically are narrow and rocky. That is because __________. large winter storm waves bring rocks onto the beach from deeper water offshore longshore transport diminishes in winter, resulting in beach starvation streams swollen by heavy winter rains bring the rocks to the shore and distribute them along the beaches the gentle wave activity of summer has removed the sand and left the beaches bare heavy winter wave activity moves the sand out to the longshore bar and uncovers the rocks underneath the sand

heavy winter wave activity moves the sand out to the longshore bar and uncovers the rocks underneath the sand

Eustatic changes in sea level might include: sinking of the crust due to large increases in sediment load. volcanic activity resulting in the formation of new continental crust. increased glacial melting due to the global warming. uplift related to earthquake activity. rise in sea level due to a large weight of glacier on a continental mass.

increased glacial melting due to the global warming.

The particle size on a beach:

is related to whatever material is locally available.