Chapter 10

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

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

All types of pollution are harmful, but _____ is among the least damaging forms.

oil

What is the longshore current?

water forced by waves to move along the shore

Of the following characteristics or features, which is/are associated with erosional shores?

- A coastline with lots of rugged headlands - Rocky coasts - Wave-cut benches and marine terraces - Tectonic activity

Of the following characteristics or features, which is/are associated with depositional shores?

- Bay-mouth bars - The formation of barrier islands - A large sand spit - A location near a large delta - High sediment supply

Of the following statements about coastal regions and landforms, which is/are true?

- The berm is affected by storm waves, but is typically dry and relatively flat. - The berm is located in the backshore area. - Most of the beach face is exposed during the lowest tides and covered during the highest tides. - The coastline is the boundary between the short and the coast. - The beach face is the wet, sloping surface in the foreshore area.

How does a sea stack form?

A stack forms when a sea arch collapses, leaving a vertical column of rock offshore. (The wave action that formed a sea arch will continue to erode the arch until the arch collapses.)

How is an arch formed along a sea coast?

An arch forms when a sea cave breaks through a headland or where two sea caves coalesce as they erode back due to wave action. (Wave energy on rocky coastlines is concentrated on bedrock headlands, where initially caves are formed, followed by arches.)

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 does the tide cycle affect erosion along a sea coast?

The tide cycle causes erosion to occur at different elevations along a sea coast. (Coastal areas have two high tides and two low tides each day. There may be differences in sea level of several feet between high and low tide.)

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 (A groin will help by trapping some of the remaining sand from the longshore drift. However, it will only make the problem worse for down-current properties.)

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

summer

Barrier islands are key features of some coastlines that consist of low ridges of sand that parallel the shore. - They are common along the Atlantic and Gulf Coastal Plains and are characterized by sand dunes and quiet lagoons. - The location and features of barrier islands make them popular locations for coastal development. - However, because these islands face the open ocean, they tend to be exposed to the full force of those occasional, powerful ocean storms. A friend is considering purchasing a vacation home on a barrier island. Given what you've learned about the impact of waves on coastal landforms, what information and advice could you offer your friend?

- Barrier islands tend to experience significant erosion and deposition of sand. Mitigating these effects is extremely difficult and costly. Your friend would be wise to reconsider. - A home on a barrier island is likely to take the full brunt of storm waves, making it a risky proposition. Your friend should think twice before purchasing. (Because barrier islands tend to experience significant erosion and deposition of sand, and because a home on a barrier island is likely to take the full brunt of storm waves, your friend should think carefully before purchasing the property.)

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

How is a cave created in a cliff face along a sea coast?

Wave action erodes areas of weakness in rock in a sea cliff. (Wave action is the primary force resulting in sea cave formation.)

Which way would sediment move if NO beach drift existed?

at an angle to shore