Beaches, shoreline processes, and coastal oceans

Question 1

Why is the coastal region constantly changing?

Answer 1

It changes due to waves and erosional deposition

Question 2

How many people in the US live in coastal regions?

Answer 2

80 percent of people live in easy access of coast

Question 3

What is Swash and Backwash?

Answer 3

Swash is the water that rushes up towards the shore and the backwash is the water that flows back into the ocean

Question 4

How does the berm change with swash or backwash dominated zones?

Answer 4

The berm will be bigger and thicker if the area is swash dominated and the berm will be smaller and thinner if the area is backwash dominated

Question 5

What are the different characteristics of a summer beach?

Answer 5

• swash dominates
• less energetic waves
• most of the swash seeps into the sand causing less backwash into the ocean.

Question 6

What are the different characteristics of a winter beach?

Answer 6

• backwash domination
• high energy waves
• causes the beach to get saturated from the waves causing less soaking of the swash into the sand
• net erosion of the berm

Question 7

How does a rip current form and what are its characteristics?

Answer 7

Forms when a narrow, fast moving section of water travels in an offshore direction. They can get as fast as 8 feet per second.

Question 8

What type of wave movement leads to longshore current and longshore drift?

Answer 8

A zigzag movement of water near the shore

Question 9

What is transported in longshore drift/longshore transport?

Answer 9

Long shore drift moves millions of tons of sediment along the coast regions.

Question 10

Where do longshore currents occur?

Answer 10

They occur in the surf zone as the water is too deep if it is further off the shore

Question 11

Where do longshore currents not occur?

Answer 11

they do not occur at depths greater than the wave base

Question 12

What controls the amount of longshore drift at the coast?

Answer 12

They depend on the equilibrium between erosional and depositional forces.

Question 13

What are examples of erosional shores?

Answer 13

Well-developed cliffs, in areas where tectonic uplift of the coast occurs. For example, the pacific coast.

Question 14

What are some main features of erosional shores?

Answer 14

• Sea caves - which form at the base of cliffs
• Sea arches
• Sea stacks

Question 15

What are examples of depositional shores?

Answer 15

Sand deposits and offshore islands are common. The shore is gradually subsiding. For example, the US southern coast and the gulf coast.

Question 16

What are some main features of depositional shores?

Answer 16

Spit - Linear ridge of sediment in the direction of longshore drift
Bay Barrier - bar forms if the spit extends across the bay and joins the mainland
Tombolo - sand ridge that connects an island or sea stack to the main land
Barrier Islands - extremely long offshore deposits of sand parallel to the coast

Question 17

what is a beach compartment and how does it function?

Answer 17

A beach compartment is a system that preserves a beach. The river provides sand and sediments, longshore currents distribute these sediments across the beach and submarine canyons help drain that sand away from the beach.

Question 18

What is beach starvation?

Answer 18

A point where the draining of the sand into the ocean exceeds the amount of incoming sand, causing the beach to diminish.

Question 19

What are some solutions to beach starvation?

Answer 19

• elimination of dams
• beach nourishment

Question 20

What is hard stabilization? Pros and Cons?

Answer 20

A man made structure used to protect the coast. They help protect the coast, but are usually very expensive, easily destroyed and may alter the recreational coastline.

Question 21

What is beach replinishment?

Answer 21

Artificial transport to beach to replace the lost sand. Usually very expensive and most of the sand comes from offshore areas, but they can also be taken from rivers, dams, and harbors.

Question 22

Explain the difference in sea level changes due to crustal movement and eustatic changes in sea level.

Answer 22

The crustal movement results in changes of relative sea level as the land changes height and not the sea. Eustatic changes in sea level that occur over the whole Earth because of the changes in seawater volume or the ocean basin capacity.

Question 23

Describe the two kinds of eustatic changes of sea level.

Answer 23

Changes in seawater volume: Formation or destruction of inland lakes and Ice ages.

Changes in ocean basin capacity: Seafloor spreading and the slow spreading mid Atlantic ridge displaces more water

Question 24

How does climate change and warming affect sea level?

Answer 24

When the water is cooled, it contracts which lowers the sea level. when the water is warmed, it expands which increases the sea level.

Question 25

Describe 4 types of estuaries by their geologic origin

Answer 25

Coast plain estuary - Former river valley now flooded with seawater

Fjord - Formed glaciated valley now flooded with seawater

Bar built estuary - Lagoon separated from ocean by sand bar or barrier island

Tectonic estuary - Faulted or folded down dropped area now flooded with ocean

Question 26

What is a dead zone? How is it formed?

Answer 26

Deep water anoxic layer. forms as phytoplankton in the surface die and sink down into the salty water layer, they are decayed, which uses up all the oxygen.

Question 27

Define the terms “wetlands”

Answer 27

Ecosystems where the water table is close to the surface.

Question 28

Why are wetlands valuable?

Answer 28

Wetlands are home to an enormous assortment of plants and animals
- Nurseries for baby fish; winter protection: migration stopover
- Wetlands also soak up nutrients from terrestrial runoff
- “Natures Kidney”
- Wetlands also protect shorelines from erosion, hurricanes