Chapter 10. Coasts, Beaches, and Estuaries

The land edge that is affected by marine processes is known generally as the ______.

Coast

An accumulation of sand along the shore is called a(n)

beach

During periods of glaciation, the oceans experience a(n) ______ change in sea level, as the water is tied up in ice. Subsequently, when the ice melts, worldwide sea levels go back up.

eustatic

An erosional coast ______ sediments, whereas a depositional coast ______ sediments.

loses; gains

One feature that is found on primary coasts are U-shaped narrow channels formed by glacial erosion called ____

Fiords, Fjords, or fjord

Which of the following can be found at a coast? (Select all that apply.)

• Bays

• Beaches

• River mouths

• Dunes

• Cliffs

Match the word to the correct blank in the phrase describing one of the three types of secondary coasts.

erosion ↔ Formed through ______ by waves, currents, or the dissolving action of seawater

tide ↔ Formed from wave, ______, or current deposits

animal ↔ Created through marine plant or ______ activity

Which of the following describe beaches? (Select all that apply.)

• Can be sand or gravel

• Dynamic

Imagine that you are walking from land toward the ocean. In what order would you encounter the following three beach areas? Put the first area on top.

1. Backshore

2. Foreshore

3. Offshore

Another word for the term eustatic is _______.

worldwide

Berms are low terraces found on the backshore area of beaches. Match the specific type of berm to its correct description.

• Winter berm ↔ Formed during severe storms; closer to the coastline

• Summer berm ↔ Formed by gentle waves; closer to the water

One way to classify coasts as depends on whether they predominantly lose sediments or shoreline. (Enter only one word per blank.)

erosional

A beach that is in dynamic equilibrium ______.

does not appear to change

Fjords found along the coasts of Norway, New Zealand, and Alaska were formed by ______.

glacial scouring

During what time of the year is it more likely for large storm waves to carry sand from the beach and deposit it in offshore bars?

Winter

Which of the following is not a secondary coast? One that is formed ______.

from river, glacier, or wind deposits

Match the term associated with wave movement and sediment transport along the beach to its correct description.

• Onshore current ↔ Landward motion of water

• Onshore transport ↔ Landward movement of sediment

• Longshore current ↔ Motion of water parallel to shore

• Longshore transport ↔ Movement of sediment parallel to shore

Match the area of the beach to its correct description.

• Backshore ↔ Dry region of the beach that is rarely submerged

• Foreshore ↔ Extends from the dry beach area to the low-tide level

• Offshore ↔ The shallow-water area seaward of low-tide level

Water rushing up onto the beach is called ______, and the resulting water moving back to the sea is called ______.

swash; backwash

A summer berm is formed by gentle waves in spring and summer, whereas a(n) ____, or storm berm is formed higher up on the beach by strong storm waves.

winter or winter berm

The energy to transport beach sediment comes from ____ and the currents they produce.

waves

A beach that appears not to change is likely in a state of ______ equilibrium, with the loss of sand equaling the gain of new sand.

dynamic

During this season, sand is frequently pushed back onto the beach from offshore bars.

summer

The movement of water and sediments toward the shore is called ____ current and transport, whereas the resulting movement of water and sediments parallel to the shore is called ____ current and transport.

• onshore

• longshore

The result of swash and backwash is ______.

a zigzag movement of water along the swash zone

What is the name given to a beach that connects the shore to an island, as shown in this image?

Tombolo

What is the direct source of energy for the transportation of beach materials?

Waves

True or false: The majority of the world's population lives within 100 km (60 mi) of a coastline.

True

Match the structure used to protect beaches to its correct description.

• Breakwater ↔Built parallel to shore to protect the coast from wave energy

• Jetty ↔ Built perpendicular to shore to protect the coast from wave energy

• Groin ↔ Built perpendicular to shore to trap sand carried in longshore transport

This photo of ____ ____ , California, is showing the dredging of sand necessary to keep the harbor open. The structures were built without considering the effect of the longshore current and drift.

• Santa

• Barbara

Match each beach area with its corresponding shape and/or structure description.

Spit ↔Extends outward into the water and runs parallel to the shore

Hook ↔ Extends outward from the shore in a wide, sweeping arc

Tombolo ↔ Extends outward from the shore and connects to a rock or an island

Which of the following statements correctly describe the history of Ediz Hook? (Select all that apply.)

waves

Which of the following statements correctly describe the history of Ediz Hook?

• The hook is naturally supplied with sediment from the Elwha River.

• The construction of bulkheads along cliffs blocked sediment supply to the hook.

• The hook originally formed from glacial sediments that were reworked as sea level rose.

The majority of the world's population lives ______.

within 100 km of a coastline

A(n) ____ is a semi-enclosed body of salt water with a free connection to the ocean, and it has a freshwater source that dilutes the salinity of the water.

estuary

Which of the following structures is used to protect beaches from wave energy and is built parallel to shore?

Breakwater

Which of the following statements correctly describe the Santa Barbara, California, harbor project? (Select all that apply.)

• A jetty and breakwater were constructed to form a boat harbor.

• Dredge pumps are used to keep the harbor open.

• The longshore current was blocked.

What type of estuary is shown in this image? (Hint: The darker the color, the more dense the water.)

Salt wedge estuary

The primary mechanism for one-way mixing, or entrainment, of the two different waters in a salt wedge estuary is from the ______.

high-salinity waters moving up into the river, raising the salinity of the seaward-moving fresh water

The installation of a(n) ____ of the Elwha River cut off the sand supply that kept Ediz Hook, as seen in the photograph, in place. After a long time and a lot of money, this structure was removed.

dam

A(n) ____ ____ estuary is shown in this image.

well; mixed

What is an estuary?

It is a type of semienclosed body of salt water in a coastal zone.

The ____ ____ estuary shown in this image has a circulation system that rapidly exchanges water between the estuary and the ocean.

• Partially

• Mixed

True or false: The classification of some estuaries may change seasonally.

True

What type of estuary occurs within the mouth of a river flowing directly into salt water? Here fresh water flows out to sea at the surface, and denser seawater flows upstream along the river bottom.

Salt wedge

What is the net circulation of the water in a partially mixed estuary?

Seaward at the top and landward at depth

What controls the rate of mixing in a salt wedge estuary?

Rate of river discharge

Estuaries found in bays located near 30°N and 30°S ______. (Select all that apply.)

• are known as inverse estuaries

• have high evaporation rates

What type of estuary has strong tidal mixing and low river flow, which creates an overall seaward flow of water?

Well-mixed

What is the flushing time in relationship to an estuary?

The time it takes for the estuary to exchange its water

What type of estuary has a strong net seaward flow of fresh water and a strong inflow of seawater at depth?

Partially mixed

Which of the following is not an important reason for understanding net circulation patterns within estuaries?

Estuaries have not been developed and may contain important natural resources.

True or false: Every estuary is easily classified into four categories.

False

Over many tidal cycles, the net movement of water in a partially mixed estuary is toward the ____ at the surface and toward the land at depth

sea or ocean

Estuaries in regions of high evaporation are sometimes called ____ estuaries because the net circulation pattern is of high-density water flowing out to the ocean at depth, while ocean water flows landward at the surface.

inverse

____ time is the length of time needed for an estuary to exchange its water.

Flushing

What is the primary impetus for understanding the circulation systems of estuaries in order to keep them healthy and productive?

Population pressures on estuaries are high.

Inverse estuaries are generally found between