The Louisiana Berm: A Coastal Fix or an Introduction to New Problems?

by Orrin H. Pilkey | June 29th, 2010
posted by Erica Rowell (Editor)

Permalink | 3 comments

Sand berms. Louisiana’s governor has promoted them; others have cautioned against them. Which side is stronger, the pros or the cons?

beach restoration
To create the berm, sand needs to be pumped from nearshore locations a la the process used in beach renourishment projects like the one shown here. (WikiCommons)

Promoting the placement of small ridges of sand, or berms, in front of selected barrier islands along the rims of the Mississippi Delta has been a very political process pushed by a state government anxious to try something — anything — to mitigate the environmental disaster thrust upon them. But sometimes doing something is worse than doing nothing.

The project got underway earlier this month. Then in the last few days it was stopped at least for the moment. I believe that the outcry from the scientific community was one reason and I suspect the economics of the project became more and more untenable. But then yesterday, dredging started up again.

The Backstory

For weeks, Governor Bobby Jindal has energetically promoted the use of sand berms as a means of coastal protection.

In late May the U.S. Army Corps of Engineers approved a six-section, 45-mile-long berm that will be 300 feet wide and extend six feet above the mean tide line (the state’s initial request for 128 miles of berm might yet be permitted).

The White House approved the project in early June.

BP agreed to pay the estimated $360 million for the initial berm — a cost projection that, based on pre-determined nourishment costs for reconstructing barrier islands, the Interior Department believes is a bit optimistic.

Map of Chandeleur Islands
Last Tuesday the berm project was temporarily halted because of a missed deadline to stop dredging in sensitive areas that could create erosion issues for the Chandeleur Islands. (NASA)

By mid-month, dredging work began.

And then last week in keeping with the project’s original terms, the Interior Department ordered a halt.

Yesterday, after a temporary source pipe had been moved (because it was endangering the Chandeleur Islands), dredging resumed.

Too bad.

The Idea Behind the Berms and Their Potential Problems

Since its proposal, the berm has been fraught with uncertainty, and it’s clear that few coastal scientists believe it will work (see here, here, here and here). Here’s a look at what scientists see as potential hazards surrounding the project.

Where to site the berms is an important step. In general, placing the sand on the islands proper would not work, as doing so would destroy animals, birds, and bird-nesting environments that are among the very things the berm aims to protect.

Instead the sand would be placed in the surf zone in front of some of the narrow, low-lying barrier islands. The idea is to prevent the oil from coming into the marshes by letting it pile up on the sand berms to be cleaned up later.

The creation of a steep slope would hasten erosion. The placement of the berm will produce an offshore slope ten times steeper than the natural one. Such a steep slope will allow less wave friction with the bottom and increase the average wave size striking the beach. The result will be rapid erosion even without storms.

More dredging and additional time will likely be needed. The proposed offshore dredging site contains a very muddy sand. As a consequence, more dredging and more time will likely be required to get a true sandy berm in place.

Storms pose multiple problems. Sections of the berm that block tidal inlets will almost certainly be re-opened by the first small storm to hit the coast. (Inlets are needed to “drain” fresh water influx as well as tidal exchange. If the inlets are closed up, nature quickly makes a new one!)

The berm can and probably would be quickly removed by storms. It wouldn’t take a hurricane to do this. Waves from a small tropical storm well offshore could do the trick, and the sand from the berm (probably mixed with a lot of oil) could then be expected to be pushed ashore and cover the bird-nesting areas that are supposed to be protected.

If a hurricane comes ashore, the berm would play almost no protective role, and oil spiked ocean water would penetrate miles into the marshes.

The bottom line is that the berm probably won’t be done in time to help with this oil spill, nor will it remain in place for the next one.

Do the scientists and engineers who are skeptical about the project have a better idea? Unfortunately, there is no silver bullet to solve this horrendous environmental problem. There is no good fix to prevent oil from washing up on the shorelines and into important wetlands and marshlands. So why spend a huge amount of money on a project that will likely make little difference and may even create further problems?

A Possible Silver Lining

Among the numerous problems created by the berm is one that may dramatically affect the U.S. East Coast. The effort to make a 45-mile-long (or perhaps longer) berm would require using most of the available American dredges, especially if it’s to be built quickly. This means that the cost of nourished beaches this year and perhaps for years to come would most likely skyrocket, and probably a number of planned East Coast nourishments would be canceled.

In some ways this might be a harbinger of things to come for East Coast beach communities. As sea level continues to rise, beach nourishment will become less and less fea
sible because of diminishing sand supplies and increasing rates of beach loss. A few years without beach nourishment might precipitate some community thinking about the future and the need to prohibit more hi-rise building and to move some buildings back from the shoreline. In that case something very good could come from the berm project!

Orrin H. Pilkey is a James B. Duke professor emeritus at the Nicholas School of the Environment. His latest book, The Rising Sea, co-authored by Rob Young, was published in 2009.

Bill Chameides is on vacation. He will be back in two weeks.

filed under: ecosystems, faculty, guest, oceans, oil, policy, politics, science
and: , , , , , , , , , , ,


All comments are moderated and limited to 275 words. Your e-mail address is never displayed. Read our Comment Guidelines for more details.

  1. Jim
    Jun 30, 2010

    Everyone was clamoring for action, and to the politicians and bureaucrats taking some action looks better than taking none, even if that action is inneffective. After it is said and done and we have the data, then when they want to build berms for the next oil spill they can point to this one and say that they didn’t help.

    • Dr. Pilkey
      Jul 1, 2010

      One of the problems I see with post mortems of beach projects is that there is a strong tendency for the engineers and scientists who designed them to look at their work through rose-colored glasses that place the blame for the failure on anything but the project itself. For example, one approach is to admit that the berm didn’t entirely prevent damage from occurring but that it would have been even worse had the artificial berm not been there. Other times the damages are laid at the foot of a “sudden, unexpected and unusual storm” that no berm could have protected the coast from. In the case of the Louisiana berm, BP is agreeing to careful monitoring of the berm and the leading candidate to do this is a Nicholas School graduate. Given this setup, I am sure that no “unexpected and unusual storm” will be blamed for the berm’s performance, however it turns out.

      • F
        Jul 3, 2010

        Sure, there is pressure to “do something”, but it should be resisted, not gamed for popularity points. Doing nothing will nearly always be better than doing the wrong something – and you have a much greater chance for doing the wrong thing when you flail about wildly. Doing nothing, or at least not doing the wrong thing, is always better when the evidence already suggests it is the right course of action. Taking different actions which may help (with possibly varying degrees of success), and which cost little, and which have a low likelihood of doing harm, are the way to go. It’s as if there is this belief that berms will be built, oil will get on them, they’ll be cleaned up, then it will all be over. I rather think this new “feature” has already taken its coat off, and is going to stay a while. The next time they want to build berms, they can point to this one and say, “We know what we did wrong, we can do it better this time.” There will also be some retro-spin claiming that, “It was more effective than people think.”

©2015 Nicholas School of the Environment at Duke University | Box 90328 | Durham, NC 27708
how to contact us > | login to the site > | site disclaimers >

footer nav stuff