Why our best beaches won't stay put
Steve Leatherman is a world-class expert on North America's barrier islands.
Steve Leatherman talks about barrier islands
“Barrier islands change shape and move, which is the way nature works. But that doesn’t work very well with our set boundary lines. It’s our idea of property and where buildings need to go versus the dynamic shorelines.” said Stephen Leatherman, Director of the International Hurricane Research Center at Florida International University in Miami. In October 2005, amid an active hurricane season and about a week before hurricane Wilma hit southern Florida, Dr. Leatherman spoke with Earth & Sky’s Eleanor Imster.
Imster: Are barrier islands a natural feature of coastlines around the world?
Leatherman: Barrier islands are actually fairly unique. Only about thirteen percent of the world’s coastline is fronted by barrier islands.
Imster: What kinds of landmasses have barrier islands?
Leatherman: The areas that have barrier islands are typically sandy plains, we call them coastal plains, which are low lying. Off of those we find the barrier islands, like Cape Hattaras, North Carolina.
Imster: Galveston, Texas is a barrier island. Is that true?
Leatherman: Yes, Galveston is a barrier island. Again, there’s the big Texas coastal plain. It’s where we find our barrier islands in the United States, along the Atlantic and Gulf coastal plain. You generally don’t find them any farther north than Long Island, because that’s where it ends.
Imster: What barrier islands do to help us is lessen the impact of big storms?
Leatherman: Barriers actually are perfectly named. They are barriers to waves and surges, particularly during storms, to protect the mainland. And also they create bays and lagoons and marshes.
Imster: Is it a natural process for storms to destroy barrier islands?
Leatherman: Storms don’t destroy barrier islands. They reshape them. As humans, we may think of them as being destroyed, in the sense that our roads, and our networks, and our houses can be destroyed. But barrier islands have existed for thousands of years and they will persist for the future.
Imster: So, barrier islands change shape. And they move too, right?
Leatherman: Yes, barrier islands do change shape and move, which is the way nature works. But that doesn’t work very well with our set boundary lines. It’s our idea of property and where buildings need to go versus the dynamic shorelines.
Imster: I’ve read that it’s not a good idea to build on barrier islands. Why would barrier islands care if they have houses and roads on them?
Leatherman: Barrier islands don’t really care if there are houses or roads, except that they need to move over time. The shoreline is very dynamic and always changing. But over time, sea level is rising. The barriers have to move landward to maintain their elevation above the rising water. But this migration, through overwash and cutting inlets, is very destructive to our buildings and to our roads and infrastructure. So, there’s a conflict there, a very stark contrast between a dynamic environment and our concept of a static environment.
Imster: The natural process is that barrier islands move and shift. But what do we do when barrier islands have people living on them, even cities like Galveston? We really want them to stay where they are…
Leatherman: Galveston’s a good example. After the great hurricane of 1900, which overwhelmed that island with a fifteen–foot storm surge and drowned between six and eight thousand people, the Corps of Engineers built a seawall. And they built the seawall about 300 feet back from the then shoreline. By the nineteen forties or fifties, the beach was all gone. The seawall is now sitting out in deep water. There is no beach along most of Galveston. That’s the compromise they’ve made there to try to protect the development.
Imster: But how long can Galveston hold on?
Leatherman: Well, they’ve lost their beach. And it’s a high expense to try to maintain the seawall, because the seawall wants to fall in now, so they have to bring in huge boulders to put at the toe of the seawall to protect it. So, you’re building structures to protect structures to protect structures. Ultimately, over the longer term, that will fall in too, unless more is done.
Imster: If we just left barrier islands alone, although that’s really a meaningless concept in this human world, would they adapt? Would they move and shift as sea levels rise and fall?
Leatherman: The barrier islands are going to move and shift anyway, whether we leave them alone or not. In some places, it’s going to become a complete confrontation, what I call a collision course. But yes, if we leave them alone they’re going to shift as they have for thousands of years. Some barrier islands used to be miles offshore. We’ve tracked some of them back six thousand years. We know barrier islands were out on the continental shelf, and they’ve moved landward that amount over the last six thousand years as sea level has slowly risen.
So, they’ve already shifted huge amounts during our time period, the human time period of a hundred years or less. The climate is warming and global warming has two implications for barrier islands. One, as we mentioned, is rising sea level, which is already occurring. Sea level has risen about eighteen centimeters world–wide in the last hundred years. Although in the Gulf coast of the United States, it’s more rapid in some areas because the land is also sinking.
The other situation is potential for more powerful hurricanes. There are a lot of recent articles on this topic perhaps relating some of the recent hurricanes we’ve had to a warmer environment. It makes sense. It’s not proven yet.
Imster: Let’s assume that it will continue to be a human world. We influence the whole earth. We’re here. There’s no going back to a world of wilderness.
Leatherman: You’re absolutely right about that. A lot of people say, “We should never have developed barrier islands.” Well, they’re right, considering the type of dynamic landform they are. But the other thing is, our best beaches in the country are barrier beaches. On my list of to ten beaches every year, many of them are barrier beaches Sanibel Island, Perdido Key, Cape Hattaras. All these are barrier islands. They’re fantastic beaches and you can understand why people want to live there. You’ve got the ocean at your footsteps. You’ve got the sea breeze, beautiful vistas, and all sorts of water sports. But the problem is that we have gone there, we have developed them. And now, how do with live with them?
Imster: Let’s take two scenarios. First, let’s say we don’t worry about all this. We just keep on developing barrier islands as we are now. What will happen?
Leatherman: Well, like the Galveston story, the first thing you see is the beach starts eroding, because the island is trying to move landward. We’re also trying to stop all the overwashes surges coming across the island that move sand from the ocean to the bay side because they’re not conducive to our way of living in developed area.
And what do we do in this country? We’re spending hundreds of millions of dollars trying to maintain beaches through beach nourishment. We’re dredging sediment from offshore trying to restore the beach, trying to hold the barrier island in place and not let the shoreline move. We’re trying to hold the hold the line. And it’s expensive. If you want to fight nature, you’re going to have to pay.
Imster: I know on some barrier islands, such as Anna Maria Island in Florida where my family likes to go, they’re bringing in sand to try to keep the beach as it was.
Leatherman: One of the problems we have with bringing in sand is not only is it expensive, but sometimes you can change the character of the beach Oft times the sand is not the same color, it’s usually darker, when it’s brought in from offshore. It’s also coarser, which means the beach tends to steepen up. But other people argue that it’s better than no beach at all. And I guess they’re right about that.
If you look at it strictly from the economic, commercial point of view, and the way people build, they don’t even want to think about this idea of it being a dynamic shoreline. They don’t care if it’s a barrier island. All they know is it’s a beautiful ocean right there. Let’s build on it, maximize our value and if we have to bring in sand, get Uncle Sam to pay sixty–five percent of it. And that’s really the idea of coastal management these days.
Imster: And barrier islands, by their nature, are shifting.
Leatherman: That’s the way they are. But when we try to nail them down, we have to pay the cost. And that’s what we seem to be wanting to do.
Imster: But bringing in sand to keep a beach in place, compared to what nature can do, it just seems rather shortsighted.
Leatherman: Well, it depends on your timeframe. It is shortsighted, but we can and have brought in huge amounts of sand. Miami Beach was restored back with something like six million cubic yards of sand. A dump truck holds about ten to fifteen cubic yards of sand. So, massive projects are being done all around the United States. As long as the sand’s there, they can do it. It’s expensive. It’s not cheap. And it doesn’t last. I call them sacrificial beaches, because you’re not curing the disease, you’re just treating the symptoms.
Imster: What about another scenario. Let’s say we try to use what we know, and be realistic at the same time. People aren’t going to quit going to beautiful beaches. What are some things we could do?
Leatherman: What’s being done in a lot of the national seashores and parks now, where they want to provide a recreational area for people, particularly in areas where the beach erosion is quite rapid, is putting all their facilities on carts, on skids so they can move them back. The facilities are moved in during the winter, or during the hurricane periods, so their bathhouses, their concession stands, this sort of thing, are not destroyed. Case in point is Assateague Island, Maryland, which is a national seashore. On the south end of the island, which is actually in Virginia, they were having damage to their facilities every year. There was such a high erosion rate this is what you call an erosion hotspot and it was getting wiped out every year. The other thing they’re doing is, instead of trying maintain the parking lot, is they’re bringing people to the beach from a staging area because they can’t keep trying to rebuild the parking lot every year.
Imster: So they’re saying, instead of trying to keep the beach here, we’re going to go where the beach is going?
Leatherman: Exactly. We’re going to go where the beach is going. It’s the same great beach it was before, it’s just not in the same location. And to the average visitor, who cares? As long as they’re able to get there, as long as they have the facilities they need to enjoy the beach. That’s the real key to it. Again, that’s going to work in national parks and seashores, and I think that’s the answer for these areas. But for South Beach, and Panama City Beach, and all these other areas, they’re already locked in and so they’re in a pitched battle with the sea to try to maintain their position unless they’re willing to fall back at some period in time, and I don’t really see that.
On the Outer Banks, North Carolina, all the houses have to be built to be moved. The whole idea is that you have a certain amount of time on that land, and when the sea comes too close you’ve got to move your house out of harm’s way. They don’t allow any high–rise buildings. It’s only single–family houses. There’s been some exceptions, unfortunately, but that’s generally the rule.I think that’s actually a pretty good principle think that’s the right thinking that’s occurred there.
Whereas if you come down to South Florida, from basically Palm Beach to Miami, you’re looking at about two to three trillion dollars of real estate right on the edge. And no one wants to walk away from that. We’re sort of between a rock and a hard place now.
Imster: Locking horns with nature…
Leatherman: We’re locking horns, exactly.
Imster: Well, in the locked horns between humans and nature, one side seems a lot more powerful. But humans are pretty smart. I guess a combination of stupid and smart.
Leatherman: It’s a funny combination, isn’t it? And of course you’ve got to realize, it’s all politics. The Corps of Engineers is in charge of our beach nourishment projects, and they’re a political animal. And as I tell people, beach nourishment’s ninety percent politics and ten percent science and engineering.
I learned a lot from this because i am doing a research paper. Thanks for the help.