Maryland Marine Notes: March-April 2000 Spotlight - Dedging the Chesapeake: The Role of Science in a Heated Debate

Volume 18, Number 2 • March-April 2000

Contents

Dredging the Chesapeake:
The Role of Science
in a Heated Debate

Science and
Human Choices

Kramer Named
Sea Grant Director

Knauss Policy Fellows

SPOTLIGHT ON SCIENCE

Dredging the Chesapeake

The Role of Science in a Heated Debate

By Jack Greer

Few would deny that the Port of Baltimore serves as a major economic engine for the region – providing some 127,000 jobs and nearly $1.8 billion worth of estimated economic benefit. There are also few who would deny that the Chesapeake Bay is a rich natural treasure, a defining feature of the region and an economic engine in its own right. But when the issue of placing dredged sediments in the Bay came to a head last year, many Marylanders found themselves lining up on either side of a great divide that pitted the improvement of shipping channels against environmental concerns.

[location of site 104 in the Chesapeake Bay]

[location of site 104 in the Chesapeake Bay]

At issue was a four-mile deep water channel just north of the Chesapeake Bay bridge, used for the dumping of dredged material until 1975 and labeled on NOAA charts as a "Discontinued Dumping Ground." The Army Corps of Engineers calls this area Site 104.

As with most highly polarized issues, the debate rapidly became acrimonious, with statements often falling into a camp of "pro" or "con." Arguments flared over the facts of the issue, and the degree to which dumping dredged material would harm the Bay's ecosystem.

Given the highly charged nature of the debate, Bay scientists faced a difficult choice – to keep their distance, or to try to contribute to a deeper scientific understanding of the issue.

"We had to ask ourselves," says Don Boesch, President of the University of Maryland Center for Environmental Science, "whether to stay on the sidelines, or to offer our knowledge and expertise."

Boesch and several of his colleagues decided to try to pull together information from a number of scientists who had worked on issues relevant to the dredging question. They began assembling an assessment team, drawing on the research and insights of some sixteen scientists who had worked extensively in the Chesapeake Bay over a period of many years.

"The report was entirely unsolicited," Boesch says. "We didn't even tell the state agencies or others that we were doing it, because we wanted to reach our conclusions independently."

The results of their effort, collected in a report entitled Science and Site 104, brought a new level of science to the debate, but it also raised more complicated questions about the role of science and the difficulty of contributing scientific perspectives in the midst of a highly politicized controversy.

A Flood
of Sediment

Researchers estimate that more that 90% of the sediment that normally comes down the Susquehanna River is deposited in the area of the Bay north of Baltimore Harbor. Given this on-going process of sedimentation, some experts estimate that keeping Bay shipping channels open will mean removing 4.5 million cubic yards from the Bay each year – an amount of silt roughly equal to that which rivers annually carry into the estuary from cities, farm fields and construction sites.

Estimated Yearly Sediment Input into the Chesapeake
Source	Amount of Sediment

Rivers	4.3 million cubic yards
Shoreline Erosion	4.7 million cubic yards

The Dredging Debate

In a shallow estuary like the Chesapeake Bay, only repeated dredging can keep channels clear for big ships. Currently, according to the Maryland Port Administration, there are a number of sites that receive sediments dredged from shipping channels – such as Hart-Miller Island, Pooles Island and now Poplar Island – as well as proposed areas, such as Cox Creek. Based on the Port Administration's projections for the next five years, and given current disposal sites, they still need to find a place for some 18 million cubic yards of dredged sediment.

The proposal to deepen and widen channels into Baltimore and to dispose a portion of the dredged material in Site 104 – the deep trench between Sandy Point and Kent Island – has sharpened disagreements between differing interests. On the one hand, the Maryland Port Administration has cited the need to improve the safety of shipping in the northern Bay, including improvements to the 35-foot-deep C & D Canal. On the other, environmental groups like the Chesapeake Bay Foundation, apprehensive about possible environmental impacts, strongly oppose dumping dredged sediment in the Bay's deeper waters. Many Bay-area citizens have joined in an effort to halt the reopening of Site 104 and voiced strong opposition to "open water" disposal. They ague that dumping dredged material will release stored-up nutrients and contaminants into Bay waters and cover bottom-dwelling organisms.

It is fair to say that since Site 104 was last used as a dumping ground, public perceptions have shifted and sharpened. At least by the 1970s, for example, large stretches of underwater Bay grasses began to disappear, a trend most likely made worse when Tropical Storm Agnes unleashed a torrent of sediment and nutrients into the Bay in 1972. Since then, scientists have blamed a lack of light – due to suspended sediments and to an overabundance of nutrients – as the primary culprit in the dramatic die-off of underwater grasses.

For two decades many who live in Chesapeake Bay country have worked to keep sediments and nutrients out of the estuary. Many farmers have instituted Best Management Practices, including no till farming, buffer strips and cover crops. To help slow runoff, construction sites are now ringed by sediment fences and hay bales. And to help protect sensitive shorelines, laws such as the Critical Area Act curtail the activities of builders and citizens along the border of the Bay and its tributaries.

After years of educational efforts and policies aimed at keeping silt out of the Bay, citizens appeared outraged at the idea of dumping dredged material into open waters. Columnist Eric Smith, of the Annapolis Capital, argued that citizens would be heavily fined for dumping even a small amount of dirt into the Bay, while large economic powers might be allowed to dump millions of cubic yards of dredged material in the middle of the estuary.

To many, the idea of taking dredged sediment from one part of the Bay and dumping it in another seemed just plain wrong.

The Role of Science

Science, including marine science, is no stranger to controversy, but debates such as this one always place scientists in a difficult position. Most marine scientists, after all, entered their fields because of an intense interest in, and a deep concern for, the marine environment. But because they are scientists, they must place the scientific method and objective data above all else – otherwise, the term "science" becomes meaningless.

In bringing university researchers together, says Boesch, his aim was to address the scientific understanding of key issues that were being raised as part of the debate. These included the effects of moving dredged material on the Bay's nutrient dynamics, the movement and impact of dredged material that did not settle into the deep trough, the effects of newly dredged material on sediments in the trough itself, and the effects of dredged material on fish and shellfish. They also considered the issue of alternative placement.

Boesch met with colleagues and began to assemble a draft, which he then circulated among a wider scientific team. Through numerous discussions – in person, over the telephone, by fax and e-mail – they came to consensus on a number of points. The result was their synthesis report: Science and Site 104, released during the fall of 1999. The report does not present a comprehensive study of the disposal site per se, but rather draws on research done by scientists in the recent past on sedimentation rates, nutrient dynamics and ecological response to change. Rather than advocate a particular action, the report's objective, according to Boesch, was to provide useful insights at a time when the Army Corps was beginning to improve the environmental impact statement that they had withdrawn during the summer of 1999.

Because there will always be uncertainty, some level of risk in scientific prediction, it was important says Boesch to give some measure of confidence to their best scientific knowledge. Accounting for these varying degrees of uncertainty, the researchers came up with the following judgments:

Effects on Nutrient Loading

Dumping dredged material from the shipping channel at Site 104 would add a small fraction of phosphorus and a more substantial portion of nitrogen to the already overenriched upper Bay. The addition, however, would equal less than one percent of nitrogen inputs from land and atmosphere during a 5-year period. High degree of certainty.
The effects of this movement and injection of nutrients in dredged sediments would stimulate algal blooms locally and only for a few weeks; they would not affect algal biomass or reductions in oxygen (hypoxia) in a perceptible way in the upper Bay. High degree of certainty.

Transport and Fate of Dredged Sediments

The physical characteristics of the silt and clay bottom of the deep trench would not change dramatically. High-to-moderate degree of certainty.
Small plumes of sediment would drift off Site 104 during dumping, settling out in a matter of hours, with few effects. High degree of certainty.
A substantial majority of the sediments would permanently remain within the site 104 trench – models predict 6-12 percent would escape. Moderate degree of certainty.
Sediments eroded by tidal currents would mostly be redeposited along the deep channels of the Bay and not settle on sensitive shallow-water habitats. High-to-moderate degree of certainty.

Effects of Sediment Contaminants

Because contaminant levels in the dredged sediments are similar to background levels in the Bay's silt and clay bottom, and because potentially toxic compounds are generally bound to silt and clay particles, the threat of toxic effects from the dumping appears quite small. High degree of certainty.
After placement of dredged sediments, concentrations of chemical contaminants in the surface sediments at Site 104 will be similar to those present now, although contaminants could be taken up by organisms for a short period following placement. Moderate degree of certainty.

Effects on Fish Habitat

Though information is sparse on habitat use by specific species, the report notes that Site 104 is located in the narrowest reaches of the Bay and contains deep water that is generally warmer than surrounding bottom areas in winter. These two features (depth and temperature) suggest that the Site 104 area may be of unusual importance both as a corridor for migrating fish moving to complete their life cycles, and as a thermal refuge during cold winter periods. Low degree of certainty.

This last point, although made with less certainty due to a lack of long-term scientific observation, raises a concern about impacts to some species of fish, among them sturgeon, that might use these deeper trenches as a refuge. This might be especially important in winter, when deep waters remain warmer than rapidly cooling surface waters, and when these lower layers of the Bay contain more oxygen than in summer.

Finally, the report notes that "all options for placement of dredged sediment have some potentially deleterious environmental consequences; without careful comparative analysis it cannot be concluded that placement of dredged sediments at Site 104 is inherently more deleterious than the alternatives."

Given the charged atmosphere surrounding the issue, how has the report Science and Site 104 been received?

Since [1975 when] Site 104 was last used as a dumping ground, public perceptions have shifted and sharpened.

The Difficult Middle Ground

Says Frank Hammons, Manager of Harbor Development for the Maryland Port Administration, "We were very happy with the scientific report that came out [from UMCES]. It seemed very balanced, accurate and fair." Hammons adds, "We can't afford to cause a problem in the Bay. We try to take a very balanced approach."

"It's a good paper," says John Gill of the U.S. Fish and Wildlife Service about the UMCES report, adding that he found it "very interesting." Gill says that he agreed with many of the assertions in the paper, but disagreed with others. He thought, for example, that the report underplayed the effect of nutrient releases from the dredged material. As far as public reaction, Gill says that the timing of the report's release – in the midst of a difficult debate – "didn't help." Many tended to gauge whatever information was put forward in a political context.

When asked about the same report, Michael Hirschfield, senior scientist for the Chesapeake Bay Foundation (CBF), preferred not to discuss it. "The issue is still too politically charged," he says.

In its public communications, such as the quarterly newsletter, Save the Bay, CBF has hit the Army Corps' assessment hard. In the fall issue, the newsletter stated: "CBF scientists assessed the Corps' original environmental impact statement and found significant flaws and inconsistencies, particularly with regard to nutrient releases and impacts to crab and fish habitat."

According to Gill, the Fish and Wildlife Service also found inadequacies in the original environmental impact statement, in the assessment of alternatives to Site 104, for example.

"People were already polarized," says Tom Miller of the UMCES Chesapeake Biological Laboratory and one of the scientists who contributed to the report. "It would have been better to put this kind of holistic synthesis up front," he says, "earlier in the process." Nevertheless, says Miller, even though it faced some difficult challenges the effort was "important to do."

In addition to the difficult timing of its release, Miller says that the researchers also faced the difficulty of applying their overall observations to a "particular place at a particular time," where data may be scarce. It would be better, he says, to have considered the dynamics of the entire upper Bay, and not just this small defined area (Site 104), before making decisions that may affect the ecosystem. "We came up with answers that are limited in scope, because the approach was limited," says Miller.

Miller feels strongly that additional research is needed to characterize the behavior of fish in the deep trenches, during winter, for example, or during migration. According to Miller, a fellow UMCES researcher at the Chesapeake Biological Laboratory, David Secor, was one of the first to call attention to the possible value of the deep trenches as wintering grounds for sturgeon. "This could affect a wide range of organisms," says Miller. "We just don't know."

In fact, says Miller, being clear about what we don't know is often just as important as stating what we do know. And while we have considerable information about fish behavior and population dynamics in the Chesapeake Bay, he says, our understanding of the role of winter habitat for particular species in specific parts of the Bay remains murky.

For Walter Boynton, a researcher who has worked for years on Chesapeake Bay issues, the report was "hard to do." But, he adds, "It is the kind of effort UMCES ought to do." In fact, he says, researchers should try to provide this kind of scientific synthesis more often, but demands on their time – such as teaching, data collection and running research programs – make this difficult.

For Boynton, the involvement of scientists in such synthesis efforts is critical. In order to fully treat a subject, he says, "the tendency among scientists is to write something that is 300 pages long, But if it's going to be shortened, it's better for the scientists to try to do it, since they have the knowledge and experience that's needed."

Of course, he points out, it's not easy getting agreement inside the scientific community either. But then it is precisely that process of contentious scientific checks and balances that gives such work credibility, he says.

In terms of public reception, the report saw a mixed reaction – "a total rainbow spectrum," says Boynton. "Those who oppose the dumping plan didn't take kindly to it, while some managers mainly had a positive reaction."

Evidently the management community was not completely satisfied either, he notes. "I attended a meeting with the Port Administration and Army Corps of Engineers [along with other scientists]," Boynton says. "They were a bit hot about the last section, where we said that they needed to look 'more thoroughly' at other options. They were upset about the 'more thoroughly' part, since they had looked at a large number of potential sites, and felt they didn't get credit." Boynton says that the scientists advised the Corps that the public largely doesn't know about the amount of preparation that went into choosing this site. (According to the Maryland Port Administration's web site, "over 500 options were considered, dating back to the mid-1980s.")

Is Boynton bothered by the criticism from both sides of the dredging issue?

"It used to bother me but not so much any more," he says. "I've been on different sides of many fences by now. The truth is we have serious problems with coastal waters like the Chesapeake Bay – and I'm much in favor of [environmental] groups like CBF. I'm a member of CBF. I send them money. I'm glad they're there. It's just that personally, I think there are much more important and much bigger fish to fry [than the Site 104 issue]."

"But," he adds, "this debate may lead to better ways of handling dredged material. Frankly, I would be worried if people weren't objecting."

Frank Hammons, of the Port Administration, agrees that the debate is important. "I have no problem with the discussion," he says. "This is a part of democracy."

"Science has a particular and specific role to play, and it should not be used to take the place of making hard choices."

Hearing the Voice of Science

Given how polarized many debates can be among environmental, political and economic interests – whether the issue is dredging, or the connection between poultry wastes and Pfiesteria outbreaks, or managing oysters and blue crabs – how can a scientific synthesis like Science and Site 104 best be of use?

According to Boynton, they must be seen as part of a larger process. "Dealing with these issues is like baking a cake," he says. "There are lots of ingredients. We are one part of the recipe – only one part. We are not putting out the Ten Commandments here."

Science has a particular and specific role to play, says Tom Miller, and it should not be used to take the place of making hard choices.

"In our culture anything viewed as 'scientific' is considered by many to be 'irrefutable,'" Miller says. "It therefore moves the debate out of the political arena – where more 'subjective' elements need to be balanced – and becomes 'truth' and is therefore not debatable. People try to take the scientific high ground."

In the environmental sciences, however, Miller points out, issues are rarely "black and white," and in many cases, he adds, "there is not much scientific high ground to claim – maybe only a low hillock."

Rather than a scientific issue, it is really a political issue of burden of proof, Miller says. "Should those who want to use Site 104 have the burden to show that dumping is not harmful; or should those who oppose the dumping have the burden to prove that it is?" asks Miller.

Such decisions, he points out, are not the purview of science.

Both Boynton and Miller feel that university researchers have a special role to play, and a valuable perspective. Boynton points out, for example, that "there are many things in the University system to keep us objective." University scientists do not have the same relationship to a client as a consultant may have, he says. "We have no reason to put a spin on it," he notes. And given the way academic science works, if there is a "spin," it is generally ferreted out very quickly through the academic process of peer review and debate.

The aim of science, then, is to contribute a clearer understanding of the potential outcomes of an action – though that understanding can only be based on the best available data, research results and scientific experience. There will always be scientific uncertainty and there will always be risks. In the case of Site 104 as a place to put dredged sediment, UMCES researchers have addressed major environmental concerns and given their best predictions on what to expect, including how certain or uncertain they are about those predictions.

While some stakeholders may reject the report's observations out of hand, others may find the scientific summary a useful guide to strategic actions. For example, while nutrients and contaminants – well-known threats to the Bay – may not appear particularly troublesome in the case of Site 104, the altering of habitat that is potentially important for certain species at certain times of the year may prove a cause for concern.

Ultimately how the citizens of Maryland choose to act on this and other information will depend not only on the ranking of risks and uncertainties but also on ethical, aesthetic, economic and other considerations.

"We want to make decisions informed by science," says Boesch, "but the decision making process should not be left for science to dictate." Such decisions, he says, must be made based on numbers of social and political factors, since they have to do with human choices. And this is, he says, as it should be.

[barge with dredge]

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