Answers to Study Questions for Shorelines

1. Waves of oscillation = water molecules follow a nearly circular orbit and end-up very close to where they were before the wave went by. Found in open ocean where water is deeper than wave base.

Waves of translation = water molecules move in the same direction as the wavefront. Found along the shore where water is shallower than wave base.

2. fetch, wind velocity and wind duration

3. abrasion, dissolution, shock pressure, boring by organisms

4. a. wave-cut platform - relatively flat, bench-like surface

left behind by a receding cliff

b. sea stack - erosional remnant of a previously existing headland that is left isolated when its connection with the mainland is broken

c. sea arch - an arch formed by wave erosion when caves on opposite sides of a headland unite

5. Figure 20.10 with caption

6. a. beach b. sand dunes c. spit d. estuary e. tidal inlet

7. f. delta g. lagoon or sound h. reef i. and j. barrier island

8. 15,000 years ago when the N.C. shoreline was 50 miles seaward of where it is now, onshore winds built up beach ridges along the shoreline. As sea level rose these beach ridges were breached permitting the low-lying areas behind them to be flooded. This process transformed the beach ridges into barrier islands, completely isolating them from the mainland.

9.-pollution of local fisheries

-beach erosion

-potential for serious property damage and loss of life during major storms

-limitation of public beach access

-water supply

-disposal of sewage

-destruction of the region's natural beauty

10. –seawall (HS) - engineering structure built parallel to the shore to protect roads and property from wave energy

-jetty (HS) - engineering structure built perpendicular to the shore around inlets to maintain their positions

-groin (HS) - engineering structure built perpendicular to the shore to slow down the migration of sand in the longshore current

-breakwater (HS) - engineering structure built parallel to the shore in the offshore zone to provide a protected area for anchoring or docking boats

-beach replenishment - pumping of sand onto eroding beaches

-dune stabilization - construction of fences and planting of vegetation on dunes to maintain their position

-relocation - moving structures out of eroding areas

-abandonment - "allowing nature to take its course" even when it destroys structures on eroding beaches

-better site selection