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USGS CMG InfoBank: Seawalls

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Comment: 15:30 - 16:26 (00:56)
Source: Annenberg/CPB Resources - Earth Revealed 24, Waves, Beaches and Coasts
Keywords: "J. Lawford Anderson", seawall, beach, erosion, coastline, "geologic hazard", sand, sediment, cliff

Our transcription: Those who are opposed, maintain that in the long run seawalls do more harm than good because they represent a threat to the beach itself.
Coastal erosion is a natural process, and as we begin to put houses on the edges of coastlines, I mean, we're concerned about losing some of those homes, and so you want to slow the erosion.
Well, you're trying to slow something that's quite natural.
When you do that, you upset the balance of things.
Seawalls to limit erosion are also cutting sand supply.
So putting in a seawall will, for a short period of time, lessen the amount of erosion, but what the result is that sediment is no longer there to be taken to the beaches.
The beaches receive part of their sand supply from cliff sides.
And as you slow down the erosion of cliff sides, then the beaches are losing a source, an important source of their sediments.

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Page Last Modified: Thu Oct 31 04:27:55 PDT 2013  (chd)