Making a Dune
Ambience: surf, wind
Fraser:A dune is a a natural landform of a essentially, a pile of sand, but, in many cases, dunes also are built by people
Metzner: Hurricane Sandy hit the south shore of Long Island, NY, hard, flattening many of the dunes along the beach. The dunes act as buffer, protecting homes and property from the storm surge. But how a dune is made and how long it takes to form, may surprise you. I’m Jim Metzner and this is the Pulse of the Planet
Fraser: So, we’re in the Otis Pike Wilderness at the Fire Island National Seashore, and on the coast of Long Island, New York, and we’re standing in front of a long dune.
Metzner: Jim Fraser is a professor of wildlife conservation at Virginia Tech. He’s studying the effects of big storms like Sandy on local species.
Fraser: And, in this case, you can see that this dune, although it’s now in a wilderness area, it was originally built by stringing snow fencing parallel to the water. And you can see these metal stakes that are sticking several feet out of the ground. Snow fencing was attached to those stakes, and that captured the sand and built these dunes, and now the dunes are, I’d say, 12 or 15 feet high.
1:22 These dunes build remarkable fast. After Hurricane Sandy, they put some snow fencing up in in some areas right near here, and we already have eight-foot dunes. So, it doesn’t take long to build these dunes if you put that snow fencing out.
So, snow fencing is just slats of wood held together by wires. So you have two inch slats, four feet high and an inch or two between the slats.
Normally, the sand would blow across the island and create intertidal flats, let’s say, on the far side of the island, but the sand fencing the snow fencing stops it. And then, it just piles up, and with the secretion of sand, it builds higher and higher, and, pretty soon, you have this long line of dune.
Metzner: Now snow fences and dunes may be useful to people, but what about the birds and other species that inhabit the beaches? We’ll find out in future programs. Pulse of the Planet is made possible in part by the National Science Foundation. I’m Jim Metzner