COASTAL EROSIONHow can we prevent our beaches from washing

away?

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Coastlines are eroded by two types of currents:

NOAA

1. Rip currents channel water away from the beach. They often develop in areas where there are breaks in sandbars and/or jetties & groynes.

2. Long shore currents develop when waves hit the beach at angles other than 90 degrees. The currents carry sand along the shore and deposit it in slow moving areas.

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Jetties are armored structures that extends out into the water intended to protect a navigation channels or marinas.

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GROYNE – perpendicular to shore to prevent movement of sand

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Fences constructed perpendicular to the shoreline help prevent beach erosion.

But measures to increase the sand on one beach or to divert sand from shipping lanes, robs another beach down the coast of the supply of sand it needs.

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Seawalls and bulkheads are common structures used to armor much of the developed shoreline.

While they do deflect the wave energy that destroys buildings and real estate, they are only temporary measures.

They also prevent the natural flow of sand.

Without the beach, a cliff develops and eventually the ocean tears out the wall.

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Breakwaters also provide some protection.

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BEACH REPLENISHMENT

Replenishing eroded beach sand costs millions of dollars every year. Proper coastal engineering is a must, but it is still a problem without a simple solution.