Dredging Up a Problem
In order to maintain open navigation channels for ships, sediment buildup in waterways has to be scooped out periodically through a process known as dredging.
In the Great Lakes states, 60 commercial ports rely on this practice. When dredged material is contaminated, it raises questions about how to dispose of it safely.
The Cuyahoga River in northeast Ohio -- known for catching fire in the 1960s -- relies on frequent dredging. The standard practice has been to put the river muck in confined disposal facilities (CDFs). But now there’s a controversial new proposal on the table to dump the dredged material into Lake Erie, a source of drinking water for more than 11 million people.
Every year nearly 13 million tons of iron ore, limestone, cement, and salt are hauled into the Port of Cleveland and unloaded. This commerce supports more than 17,000 jobs, all of which depend on the shipping channel remaining clear.
Sediment naturally flows downstream with the current, and when it does it clogs things up. To keep the channel open, the U.S. Army Corps of Engineers removes enough sediment each year to fill a stadium (approximately 250,000 cubic yards).
“The question is then what to do with the spoils, what to do with what you dredge up from the bottom. So we’ve constantly got this, not ‘Where’s Waldo?’ but ‘Where to Put Waldo?’” said Eric Fitch, an environmental science professor at Marietta College.
Traditionally, it’s been put in confined disposal facilities near the Erie shore. Now the Army Corps, the agency charged with maintaining the nation’s navigation channels, wants to dump it into the open lake instead. Fitch said this might be a reasonable plan, though he’d like to see some pilot testing first.
Other Great Lakes harbors already submerge their dredged material in fresh water. As much as 50 percent of dredged Great Lakes sediment is placed in the open lake, once it is determined to be largely free of contaminants. Some states, including Pennsylvania, Minnesota, and Wisconsin, have attempted to ban the practice due to concerns about lingering sediment contamination.
Some northeast Ohio residents, environmental groups, and politicians vocally oppose this idea of lake dumping and say it’s an ill-advised cost-cutting measure.
“We have no idea at this point how it will contaminate the water process [or] what we’ll have to do to add additional chemicals and treatments,” said Cleveland council member Michael Polensek at a recent public hearing held by the Ohio EPA.
Long-time resident George Havens also testified at the meeting. “I’ve been living in Cleveland for 89 years and drinking this water. I’d like to continue to drink it a little bit longer. Dumping anything into the lake is unscientific, unimaginative, uncivilized, and barbaric,” he said.
The Great Lakes basin has a long history of industrial pollution, and some of those pollutants, like PCBs, PAHs, heavy metals, DDT, and its metabolite DDE, persist in the buried sediment. Current urban and agricultural runoff also contributes to the problem. The Army Corps says according to their tests on the Cuyahoga River, the sediment in the proposed dredging location is not as contaminated as it used to be. But they have faced pushback not only from citizens and NGOs but also from the Ohio EPA.
“At the end of the day they need to meet the Ohio EPA water quality standards,” said
Ohio EPA Northeast Office District Chief Kurt Princic, “and we don’t feel that’s being met.”
The Ohio EPA has to sign off on the Army Corps proposal before it can move forward. Princic says they’re concerned because the dredged material would be dumped close to the city’s drinking water intake valves. Fish toxicity is another concern. They also question the methods by which the Army Corps arrived at their conclusion that the sediment is safe enough to put in the lake.
Mike Asquith, dredging program manager for the Army Corps’s Buffalo District, said the sampling methods employed were appropriate for the situation. “All the material there is recent and storm-derived. It’s not a situation where you have legacy contamination over years of material being placed there,” he said.
University of Akron geoscientist John Peck reviewed the Corps’s methodology, and is still on the fence about whether this is a good idea or not.
One outstanding question for him was why didn’t they take samples from deeper down, where they would be dredging? “I just wonder, because you’ll vary the floods, you’ll vary the type of sediment, you’ll vary the contaminants, maybe one should just take a sediment core,” Peck said.
Concerns like this have environmental groups calling for the Ohio EPA to put the brakes on the plan and allow for further review of the science and a discussion of other disposal options.
While the Army Corps is required to deal with the material in the least expensive environmentally acceptable manner, there are other options for it. It could be stored more efficiently at the current confined disposal sites and eke out, by some estimates, another 20 years of storage. Or it could be remediated and put to beneficial use.
For instance, Green Bay, Wisconsin, uses dredged material to reconstruct a series of barrier islands, creating habitat for pelicans, cormorants, and other species. Grand Haven, Michigan, mixes their dredged material with composted municipal yard waste to create topsoil. Chicago has also experimented with reuse with their “Mud to Parks” project. At the Port of Duluth-Superior in Minnesota and Wisconsin, dredged material replaces fill dirt on construction sites, and it’s also used in asphalt production. And even Cleveland has a history of putting it to beneficial use: Dike 14 Nature Preserve is made up of material dredged from the Cuyahoga in the past.
A decision is expected from Ohio EPA by the end of March as to whether material from the Cuyahoga River will be allowed in Lake Erie. Rejecting this proposal would send the Army Corps of Engineers back to the drawing board to find another place to put this season’s cache of muck.