16.3 Shoreline Processes and Features

What is wave refraction?

• The bending of waves as they approach the shore at an angle.

• The reflection of waves back into the ocean.

• The increase in wave height as they move into shallower water.

• The breaking of waves on the shore.

Answer explanation

Wave refraction is the bending of waves as they approach the shore at an angle. This occurs due to changes in wave speed as they enter shallower water, causing them to change direction.

Which of the following best describes a longshore current?

• A current that moves parallel to the shore, caused by waves hitting the shore at an angle.

• A current that moves directly away from the shore.

• A current that moves directly towards the shore.

• A current that circulates in the open ocean.

Answer explanation

A longshore current is defined as a current that moves parallel to the shore, which occurs due to waves hitting the shore at an angle. This movement is crucial for understanding coastal dynamics.

What is a barrier island?

• A large rock formation in the ocean.

• A narrow, sandy island that forms parallel to the coast.

• A type of coral reef.

• A submerged mountain range.

Answer explanation

A barrier island is defined as a narrow, sandy island that forms parallel to the coast, providing protection to the mainland from waves and storms. The other options do not accurately describe this geographical feature.

Explain how wave refraction affects the distribution of energy along a coastline.

• It causes energy to be concentrated on headlands and dispersed in bays.

• It causes energy to be evenly distributed along the coastline.

• It causes energy to be concentrated in bays and dispersed on headlands.

• It has no effect on the distribution of energy along a coastline.

Answer explanation

Wave refraction causes waves to bend as they approach the coastline, concentrating energy on headlands where the water is shallower and dispersing it in bays where the water is deeper, leading to erosion and deposition patterns.

How does a longshore current contribute to the formation of a spit?

• By depositing sediment along the shore, extending the landform.

• By eroding the shoreline and removing sediment.

• By creating a circular current that traps sediment.

• By increasing wave height and energy.

Answer explanation

A longshore current moves sediment along the shore, leading to the accumulation of material. This process helps in extending landforms like spits as sediment is deposited in a linear fashion, creating new land.

Describe the role of barrier islands in coastal protection.

• They increase the speed of incoming waves.

• They act as a buffer, absorbing wave energy and protecting the mainland.

• They decrease the salinity of coastal waters.

• They prevent the formation of longshore currents.

Answer explanation

Barrier islands serve as a protective buffer for the mainland by absorbing wave energy, which helps to reduce coastal erosion and damage from storms. This makes them crucial for coastal protection.

Analyze the impact of wave refraction on coastal erosion patterns.

• Wave refraction can lead to increased erosion on headlands and decreased erosion in bays.

• Wave refraction has no impact on coastal erosion patterns.

• Wave refraction leads to uniform erosion along the coastline.

• Wave refraction decreases erosion on headlands and increases it in bays.

Answer explanation

Wave refraction causes waves to bend as they approach the shore, concentrating energy on headlands, leading to increased erosion there, while dispersing energy in bays, resulting in decreased erosion.

Evaluate the potential effects of a disrupted longshore current on sediment transport.

• Sediment transport would increase uniformly along the coast.

• Sediment transport would decrease, leading to increased erosion in some areas.

• Sediment transport would remain unchanged.

• Sediment transport would become more efficient, reducing erosion.

Answer explanation

A disrupted longshore current reduces the movement of sediment along the coast, leading to decreased transport. This can cause sediment to accumulate in some areas, resulting in increased erosion where sediment is normally deposited.

Predict how the removal of a barrier island might affect the adjacent coastline.

• The coastline would experience increased erosion and storm impact.

• The coastline would become more stable and less prone to erosion.

• The coastline would experience no significant changes.

• The coastline would see a decrease in wave energy.

Answer explanation

The removal of a barrier island exposes the coastline to greater wave energy, leading to increased erosion and higher storm impacts. Barrier islands act as buffers, so their absence negatively affects coastal stability.

Which of the following is a direct result of wave refraction?

• The formation of tidal waves.

• The concentration of wave energy on headlands.

• The creation of underwater volcanoes.

• The increase in ocean salinity.

Answer explanation

Wave refraction occurs when waves approach the shore at an angle, causing them to bend and concentrate energy on headlands. This results in increased wave energy in these areas, making 'the concentration of wave energy on headlands' the correct answer.