, 0/1Correct Answer:, DYour Response:, C///, 10Points Missed, 3Percentage, 77%1., Most U.S. beaches are shrinking or encroaching on the land rather than growing or moving seaward, so the land of the U.S. is getting smaller, not bigger. Which of the following is not a likely cause:, A., Global sea level is rising, covering more land.B., Dams have increased sediment transport from the land to the sea.C., Levees along rivers have blocked sediment supply to deltas that feed longshore drift, forcing the sediment to fall in deep water where waves cannot pick it up.D., Water, oil and gas are being pumped out of the ground in some places, causing subsidence.E., Sea-level rise as the last ice age ended flooded river valleys to form bays, and sediment now is deposited in these bays rather than being delivered to beaches.As sea level rises, beaches are pushed landward unless something happens to offset this tendency. Dams keep sediment away from beaches, as do the bays formed by post-glacial sea-level rise, and human-caused subsidence of the land is an important problem. But land rising would make for more land, not less., Points Earned:, 0/1 Correct Answer:, BYour Response:, E2., Often, landowners along eroding beaches will build groins, which are walls or dams sticking out into the ocean or lake from the beach. Why are these built, and what happens?, A., The landowners are trying to block the energy of the waves, which usually turn to move almost parallel to the beach; this can work, but often increases energy on the "upstream" side of the groin and makes the neighbors mad.B., The landowners are trying to catch sediment from the longshore drift to add to the beach; this almost always works well.C., The landowners are trying to block the energy of the waves, which usually turn to move almost parallel to the beach; this almost always works well.D., The landowners are trying to make a nice photographic platform from which to take pictures of their houses falling apart during the next storm.E., The landowners are trying to catch sediment from the longshore drift to add to the beach; this can work, but often erosion on the "downstream" side of the groin makes the neighbors mad.
You've reached the end of your free preview.
Want to read all 47 pages?
- Fall '08
- Erosion, Correct Answer, Cape Cod, Cape