News

Chicago Watersheds:
Gotta Keep ’Em Separated

Invasive species, such as zebra mussels and bighead carp, pose a severe threat to native food webs in the Mississippi River and Great Lakes watersheds. Mounting concern for local ecosystems prompted experts from the Alliance for the Great Lakes to investigate the full ecological separation of the two waterways to prevent the transfer of harmful species. The results were published in a recent report.

“This is not just about preventing Asian carp from getting into the Great Lakes,” explains Joel Brammeier, vice president for policy at the Alliance. “It’s about stopping the Great Lakes from becoming a net donor of invasive species to the rest of the US.”

According to the report, scientists suggest that future invasions put the Great Lakes at risk of “ecosystem breakdown.” The current water system, engineered in 1900 to reverse the flow of the Chicago River, carries Chicago’s wastewater away from Lake Michigan and supports boaters and millions of tons of cargo annually. While advocates of separating the systems don’t suggest doing it overnight, current methods such as electrical barriers still allow microorganisms and larvae to pass through. An ecological separation would allow no inter-basin transfer of any aquatic organisms.

“Here is the reality,” says Brammeier.“If you want to protect the ecology of these two great watersheds, keeping them physically separate is the only option that will give you 100 percent protection. What that means is that we have to rethink how we use the Chicago waterway system.”

The US Army Corps of Engineers has been approved to begin a full-scale feasibility study. Brammeier says Congress needs to grant an initial appropriation of $500,000 to begin work, which is expected to come this year. A 2003 conference of experts in Chicago set a target date to complete an ecological separation by 2013. “That deadline may be optimistic considering it is already 2009,” says Brammeier, “but all the more reason to get on pace to complete a feasibility study within three years. It’s that urgent.”

— Katie Chelminski