Tuesday, November 27, 2007

Dredging Up Trouble

People along Long Island Sound were arguing about dredging 25 years ago, when I was just starting as a reporter in Mamaroneck, and they're arguing about it still. If we don't dredge, our harbors and ports will go out of business; but the stuff we dredge can be badly contaminated, and so digging it up and dumping it elsewhere in the Sound can spread out and worsen an environmental problem that is relatively contained.

The Army Corps of Engineer and the U.S. EPA are holding hearings things week on the issue. Here's how Judy Benson, of the New London Day, summarizes the environmental side of things:

Dredge spoils can contain hazardous materials such as heavy metals that become mixed into the waters of Long Island Sound when excavated from one site and dumped in another. The dumped material can also end up on beaches and affect marine wildlife.

Leah Schmaltz, director of legislative and legal affairs for the Connecticut Fund for the Environment and its sister organization, Save the Sound, said her group recognizes that while there will probably always be some need for open-water dumping of dredge spoils, it would like to see the amount reduced.

“We'd like to look to a future where dumping is minimal,” she said.

The water quality of Long Island Sound, an ecologically important estuary, is compromised when sediments in dredge material are dumped, she said. Alternatives that should be considered include depositing the material in specially dug pits, on-land dumpsites and reuse for beaches and other areas that need fill. In many cases, contaminants in the dredge spoils would not be as environmentally harmful in an upland setting as they would in open water, she said.

Another environmental group that has been active in the dredging issue is the Citizens Campaign for the Environment. Adrienne Esposito, the group's executive director, said dredge spoils need not always be treated as a waste product. Some dredge spoils, she said, can be used to fill abandoned coal mines, for example. The material can also be used as an ingredient in cement, locking up any contaminants.

“It can be a raw material. It just needs to be shipped,” she said. “But in Long Island Sound, it's a pollutant. It's released into the food chain.”

The challenge, she said, would be to create a market for dredge materials to offset the costs of the shipping.

I stared out by saying I remember this debate being at least 25 years old. Those involved now may or may not take comfort in knowingthat in fact it's far older:

Between 1765 and 1821, New Haven was forced to extend its main wharf more than 3900 feet into its bay to stay ahead of the mud which would otherwise have prevented ships from landing. And yet ... there was "less water a few rods from its foot" in 1821 than there had been at the end of the much shorter wharf in 1765.

That's from William Cronon's Changes in the Land: Indians, Colonists and the Ecology of New England, which came out in 1983.



Blogger Terry said...

The Dredge spoils issue won’t go away, at least as long as we use marine transport for anything. Soundkeeper’s work with polluted runoff has demonstrated that contaminates of every description are flushed from our streets and paved surfaces the race to the harbors via storm water systems. They then become trapped in the marine sediments in the harbors. There are a lot of inputs that contaminated sediments in our harbors, anti fouling paints from boats, direct discharges atmospheric deposition etc.
Remediation of dredged sediments and reuse is the holy grail of the last 25 years but here’s the rub –it takes a lot of energy to do. Energy whether in the form of combustion driven or electric will continue to rise and be yet another limiting factor in dredge spoil reuse – a big one
I am convinced that if you get the polluted runoff you get the largest input to sediment contamination. This may not solve the issue at hand but we need to do some real hard thinking on how to get at the source of the toxins in sediments or at least out of the delivery system before they poison the sediments. If not we can talk about this over and over for the next 25 years.

8:48 AM  
Blogger Tom Andersen said...

Thanks, Terry. Like so much of what we work on, this situation is a perfect illustration of Barry Commoner's four laws of ecology:

1. Everything is connected to everything else

2. Everything must go somewhere

3. Nature knows best

4. There’s no such thing as a free lunch

10:44 AM  

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