Michigan sues to protect Great Lakes from Asian carp

Michigan wants to take steps to keep carp like these from invading the Great Lakes, which has sparked a debate about ecology and business. (Nerissa Michaels/associated Press)

A 2008 study by the Alliance for the Great Lakes found that ecological separation could be economically beneficial and improve efficiency of freight transport.

The Natural Resource Defense Council has proposed that an environmentally sustainable intermodal freight facility be built to replace barge traffic into the lake, creating "green jobs" and curbing the invasive species risk.

"This way of moving goods may have made sense in the 19th century or 50 years ago, but are we still dependent on those same decisions?" asked Henry Henderson, NRDC Midwest program director. "We built a system without understanding the full implications. Now we have to design and build an engineered solution to a human-created problem."

An ecological separation would probably mean Chicago would have to revamp its wastewater infrastructure.

"The reason Chicago reversed the flow of the river was to protect Lake Michigan from sewage pollution, but that protection is no longer needed because Chicago and every city has the technology now to clean up sewage so it's safe to discharge it into the Great Lakes," said Andy Buchsbaum, National Wildlife Federation Great Lakes regional executive director, who noted that Milwaukee and other cities discharge treated sewage into the Great Lakes. "Instead of protecting Lake Michigan, the system is now the primary vector for the biggest pollution threat the Great Lakes have faced: invasive species."

Asian carp aren't the only invasive species transported through the canals. It seems likely that zebra mussels and round gobies were introduced to the Great Lakes in ballast from oceangoing ships and then made their way into the Mississippi River basin via the Chicago River and canals. Zebra mussels deplete plankton and clog water-intake structures. Round gobies compete destructively with native fish.

The electric barrier was originally proposed to block round gobies, but wasn't implemented fast enough. The barrier didn't operate at full strength until this year because of safety and other concerns. Now the Corps of Engineers plans to spend at least $6 million in stimulus funding on a stronger electric barrier.

"I was skeptical of that barrier from the get-go," Henderson said. "This has all been ad hoc herky-jerky responses to discreet problems, when the underlying problem is staring us in the face."

Buchsbaum called the Michigan lawsuit "seismic for the Great Lakes" because it addresses the invasive species threat but also reopens the nearly century-old legal battle over Chicago's diversion of Great Lakes water.

The Great Lakes-St. Lawrence River Basin Water Resources Compact -- signed by President George W. Bush last year after a decade-long legislative process -- bans almost all diversions of Great Lakes water out of the basin, with Chicago given the only significant exemption.

About 1 percent of the Great Lakes' water is replenished each year, and advocates worry that unchecked diversions could slowly drain the lakes.