A member of Congress has proposed legislation that would order the federal government to cut off links in Chicago waterways between Lake Michigan and the Mississippi River system to protect the Great Lakes from Asian carp and other invasive species.
The bill introduced by Rep. Candice Miller, a Michigan Republican, would authorize the U.S. Army Corps of Engineers to construct barriers in rivers and canals that were reconfigured more than a century ago to connect the two giant watersheds.
That project boosted waterborne commerce but created a pathway through which fish, mussels and other aquatic animals and plants could stake out new territories and compete with native species.
"That should never have been allowed to happen and certainly would never be allowed today," Ms. Miller said, adding that the linkage also allows vast amounts of Great Lakes water to flow toward the Mississippi. "That must end."
The linkage has allowed nuisance species such as the round goby and zebra and quagga mussels to escape the Great Lakes and infest the Mississippi and other waterways.
But the threat that Asian carp pose to the Great Lakes has intensified the search for answers. Fisheries on Lake Erie, Lake Michigan, Lake Ontario and the rest of the Great Lakes are a $7 billion industry, and it would be jeopardized if the carp take over the watershed.
Already, they may be making their way toward Pittsburgh, via the Ohio River: Last autumn, the Pennsylvania Fish and Boat Commission and West Virginia Division of Natural Resources announced that circumstantial genetic evidence suggests the presence of invasive Asian silver carp in the upper reaches of the Ohio River.
Environmental DNA samples were found near Aliquippa, Beaver County, and near Chester, Hancock County, W.Va. Environmental DNA is found on material such as scales, excrement and mucous.
Silver and bighead carp, imported from Asia in the 1970s, have slowly made their way up the Mississippi and its tributaries, including the Illinois River, which leads to Lake Michigan.
In a report last month, the Army Corps presented eight options for dealing with the problem, two of which included physically separating the two watersheds. Both carry estimated price tags of at least $15 billion and a 25-year timetable for completion. The Corps has said it's up to Congress to decide which measures the agency should undertake. A message seeking comment was left with a spokeswoman.
Mark Biel, chairman of an Illinois business coalition called UnLock Our Jobs, said his group opposes both as too costly and disruptive to shipping and pleasure boating in the Chicago area while worsening the risk of floods. If the government chooses physical separation, opponents likely will file a lawsuit that would delay matters further, he said.
"We need a realistic solution that is affordable and politically palatable," Mr. Biel said.
His group favors a Corps alternative that would cost just $68 million and take relatively modest steps using chemicals, nets and watercraft inspections.
Critics say those measures would be inadequate. A recent University of Notre Dame study found that physical separation would stop 95 percent to 100 percent of Asian carp, while other methods would be markedly less effective.
If enacted, Ms. Miller's bill would require the Army Corps to begin designing a separation project within 180 days. When finished, the agency would have 180 days to begin construction.
The bill would allow federal funding but doesn't specify an amount, Ms. Miller's spokeswoman Salley Wood said.