Geo Chapter 10 Homework

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.

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.

Beach joggers prefer to run on the __________.

beach face

Features of a depositional coast may include spits, barrier islands, tombolos, and __________.

deltas

The "river of sand" described in our text refers to __________.

longshore transport between the beach and the breaker line

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

breakwaters groins jetties

How do jetties protect harbor entrances?

by inhibiting the deposition of sand in the harbor mouth

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

cost

Southern California beaches would have more sand if __________.

dams were removed from streams flowing to the coast

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

on the Atlantic and Gulf coasts

In which direction does the longshore current move?

parallel to shore

Geologic evidence suggests that eustatic (global) sea level rises have been caused by __________.

rapid seafloor spreading at divergent plate boundaries

Why are coastal stabilization structures built along coastlines?

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

What is the longshore current?

water forced by waves to move along the shore

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

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

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.

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

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 __________.

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 __________.

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