Introduction to Erosion

Beaches erode.Ironically, erosion is the very thing

which created the beaches.When oceans first covered the

surface of the Earth, there were no beaches. Only rocky shores.

Over the course of time, these rocks were broken down into stones.

Erosion

These rocks were in turn broken down into pebbles

Then into gravelAnd finally into sand.Rivers also carried sand formed in the

same way into the oceans.This is how our beaches were formed.

Why is Beach Erosion a Problem?

Over 75% of the US population lives within 100 miles of the beach.

Most communities were built based upon what was then the current location of the beach.

Beaches in some NJ communities were extremely wide.

Some beaches are getting narrower and narrower.

Why is Beach Erosion a Problem?

Entire homes have been washed away.New Jersey earns millions of dollars each

year from tourists who come to visit our beaches.

We spend millions of taxpayer dollars each year to combat beach erosion.

Sometimes NJ tax dollars are used to protect and replenish private beaches. Is this right?

Causes of Beach Erosion

WavesStorms (storm surge)CurrentsTidesWindHumans

We have built structures which disrupt the fragile balance of nature.

Waves and Beach Erosion

Tough Questions?

Once houses, or entire towns, have sprung up, we are faced with the following choice:

Succumb to nature and let the sea swallow expensive buildings? or…

Fight back and seek to control nature?

Ocean City, NJ

Another Tough Question?

On average, New Orleans is now 6 feet below sea level.

Groins

Rocky structures used to slow down beach erosion.

Jetties

Rocky structures designed to protect inlets from the erosion caused by ocean waves.

“Ironically, geologists now know that such

seawalls hasten the loss of the beach, actually increasing the waves’ ability to scour away sand.”

“Once thought to stabilize beaches, groins turn out merely to block the natural movement of sand, ultimately leading to more erosion than they prevent.” -Oceanfront Battlefront, Audubon Magazine 1998 p.53

Discussion Question

What impact will global warming have on beach erosion?