Importing Sand, Glass May Help Restore Beaches
Importing Sand, Glass May Help Restore Beaches
Coastal engineers in Florida rebuild the beaches after hurricanes but their job is getting harder. Options to restore sand range from sand bypassing, which involves scooping up sand and carrying it past obstacles like ports, to grinding glass from bottles to the same size as a grain of sand.
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NPR's Jon Hamilton has the latest installment in our collaboration with National Geographic Climate Connections.
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JON HAMILTON: The beaches around Fort Lauderdale look naturally beautiful, but they are not - natural, that is. They've had some work done. Steve Higgins knows every nip and tuck. He's Broward County's beach erosion administrator, responsible for all 24 miles of shoreline. Higgins is walking along a majestic stretch of beach at John U. Lloyd State Park.
HAMILTON: We have placed sand on this beach four times now since 1970. We dredge offshore between the coral reefs and we pipe the material onto the beach. In fact, this beach was just reconstructed ending in February of '06.
HAMILTON: The project required almost two million cubic yards of sand. That's enough to fill a line of dump trucks from Fort Lauderdale to Richmond, Virginia. But Higgins says without the new sand there wouldn't be a beach here.
HAMILTON: Do you see that boardwalk that ends at the sand coming off the restroom? That's where the cliff was. There was water. I mean, we'd be in probably eight feet of water right now.
HAMILTON: The beaches can't recover on their own because of all the ports and harbors along the Florida coast. Sand piles up north of the port while beaches to the south dwindle away.
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HAMILTON: That's the problem at John U. Lloyd State Park just below Port Everglades. Steve Higgins points across the mouth of the port; a jetty stretches hundreds of yards into the ocean.
HAMILTON: The beach on the north side goes all the way out to the beginning of that mound, and it's, you know, it's 12 hundred feet wider over there than it is here.
HAMILTON: Looking down a line of hotels that are lined up like dominos along the beach, the only thing standing between them and the course of a major hurricane is perhaps 50 yards of sand.
HAMILTON: If you have a narrow beach, you can get structures beat up, undermined, damaged, and lost.
HAMILTON: Tom Campbell is president of Coastal Planning and Engineering in Boca Raton. The firm specializes in helping local governments restore their beaches. Campbell says sandy beaches have a remarkable ability to dissipate the energy of crashing waves produced by a major hurricane. Of course, no amount of sand can save you from a direct hit.
HAMILTON: Obviously, if you have a Cat 5 coming in, even with the beach restoration, you still have some significant structural damage and we've seen that. But usually these huge storms affect hundreds of miles of coast, and in that hundreds of miles, if you have beach restoration, it gives you protection.
HAMILTON: Charlie Finkl is a marine geologist with the Coastal Planning and Engineering.
D: We need to keep renourishing the beaches to keep up with the rise in sea level. And if we don't keep up the renourishment, we're going to fall behind and then you can have bigger disasters.
HAMILTON: Unless people are prepared to retreat from the coasts, which they're not, the answer is more and more sand. Steve Higgins says there is just one problem.
HAMILTON: We're running out of sand, easily accessible sand offshore.
HAMILTON: Higgins says Broward County still has a few sand deposits within easy reach. But just down the coast, Miami-Dade is less fortunate.
HAMILTON: They're out. They have one little bit of reserve left for emergencies after storms, but essentially they don't have any more sand offshore that they can get to.
HAMILTON: So coastal engineers are looking at several options. One is sand bypassing. This restores the natural flow of sand down the coast by literally scooping it up and carrying it past obstacles like ports. Steve Higgins says bypassing is what he wants to do at Port Everglades.
HAMILTON: What it will involve is basically digging a pit right off the end of the jetty and right around the inside of it. So that way future sand that comes down the pike and goes around the jetty will fall on our in that hole and we can dredge it out every couple of years and put it on the beach.
HAMILTON: Or you can prospect for sand farther from the coast. Jeff Andrews, the vice president at Coastal Engineering, says that's already happening.
HAMILTON: Typically, a - 10 years ago you would go three to five miles off shore, but now we're going as far as 30 miles and further to get that sand and they're having to barge it into the sites. So it's really looking further and further from your project site. It's not in your backyard anymore.
HAMILTON: So Broward County is hoping to use a new approach to restoring beaches - bottles.
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HAMILTON: Truckloads of glass bottles arrive every day at this recycling center. Phil Bresee runs the county's recycling program.
HAMILTON: About 15,000 tons per year come into this facility.
HAMILTON: The bottles travel along a belt where they are sorted by color and crushed.
HAMILTON: This bunker right here is the mixed broken glass. Next to it is our clear glass, next to it is the brown; then we have the green over on this side.
HAMILTON: Bresee dreams that this could become the stuff beaches are made of.
HAMILTON: You can grind a piece of glass down to the same size as a grain of sand and make it have the same geotechnical characteristics as a grain of sand.
HAMILTON: The county has already done a small experiment. It tested different mixtures of glass and sand on a local beach. The ground-up bottles seem to act just like regular sand, even providing the right environment for loggerhead turtles to lay their eggs. Now, Bresee says, the county is eager to expand its experiment.
HAMILTON: We want to put 2,000 cubic yards of this material in the surf line and see what happens to it. Does it get washed out to sea at the same rate as natural sand? Does it stick to the surf a little bit more? How quickly does it blend?
HAMILTON: Jon Hamilton, NPR News.
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