CH 10

How do jetties protect harbor entrances?

by inhibiting the deposition of sand in the harbor mouth

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

In which direction does the longshore current move?

parallel to shore

What is the longshore current?

water forced by waves to move along the shore

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

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

Why does the beach in the video look the way that it does during wintertime?

Large waves move sand offshore onto longshore sand bars and create a rocky beach.

In the long term, what do beach drift and longshore current do?

Move sediment parallel to the shoreline

What would you do to both grow a large beach and protect a harbor mouth?

Place two jetties on either side of the harbor mouth, and build a breakwater upcurrent from the harbor mouth.

Why does the beach shown in the video look the way that it does during summertime?

Small waves move sand up the beach face and create a wide, sandy beach.

How would a beach be affected if a wide berm were protected from erosion during winter months?

The wintertime beach would look similar to the summertime beach.

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

summer

Wave refraction is __________.

the bending of waves

Why are coastal stabilization structures built along coastlines?

to protect coastal property from wave erosion to stop beach sand erosion

The image below depicts shoreline features characteristic of depositional coasts. Match the correct letter to each of the following features.

1. B: Spit 2. E: Lagoon 3. C: Barrier island 4. A: Tombolo 5. D: Bay barrier 6. F: Delta

On this perspective view of a barrier island, match the correct letter to each of the following features.

1. D: Barrier flat 2. C: Peat bed 3. F: Lagoon 4. A: Salt marsh 5. B: Dune 6. E: Ocean beach

On this diagram showing a perspective view of California's Santa Barbara Harbor, match the correct letter to each of the following items.

1. D: Breakwater 2. A: Area of sand deposition 3. C: Arrow that points in the OPPOSITE direction of longshore drift 4. F: Dredge 5. B: Arrow that points in the direction of longshore drift 6. E: Area threatened by erosion after construction of the breakwater

This image shows a variety of beach and shoreline features. Match the correct letter to the regions and/or features listed below.

1. H: Longshore bar 2. B: Offshore 3. A: Berm 4. F: Coast 5. C: Shore 6. D: Wave-cut cliff 7. E: Nearshore 8. G: Beach 9. I: Beach face

The image below depicts shoreline features characteristic of erosional coasts. Match the correct letter to each of the following features.

1. H: Sea cave 2. D: Headland 3. B: Sea arch 4. F: Uplifted marine terrace 5. C: Wave-cut bench 6. A: Coves 7. G: Blowhole 8. E: Sea stack

In general, what do beaches look like at the end of winter?

Beaches tend to have a narrow berm and a prominent longshore bar.

In general, what do beaches look like at the end of summer?

Beaches tend to have a wide berm and no longshore bar.

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.

How are winter beaches different from summer beaches?

Winter waves are short and high, whereas summer waves are long and shallower.

How long does it take berms to become narrow and rocky after summer has passed?

a few weeks

Which way would sediment move if NO beach drift existed?

at an angle to shore

Which of the following structures are types of coastal stabilization structures?

jetties breakwaters groins