TRAVERSE CITY, Mich. (AP) — Thirty-one members of Congress prodded the U.S. Army Corps of Engineers on Friday to consider a multi-billion-dollar plan released this week for cutting a Chicago-area link between the Great Lakes and Mississippi River watersheds to stop migration of Asian carp and other invasive species.

The lawmakers said a blueprint commissioned by two organizations should help the corps speed up its own study of how to shut down aquatic pathways between the two drainage basins, scheduled for completion by late 2015. Critics say that’s too slow, with Asian carp threatening to use the Chicago waterway system to reach Lake Michigan, where scientists say the voracious fish could devastate native fish populations by gobbling up plankton at the base of the food chain.

The proposal from the Great Lakes Commission and the Great Lakes and St. Lawrence Cities Initiative offers three alternatives for separating the two watersheds by placing barriers at key locations in the Chicago waterway system. It estimates the price tag at $3.3 billion to $9.5 billion.

“We ask how the corps will use the thorough analysis provided in this new report and how the corps will be able to shorten its time frame for completing (its study) by incorporating the new information contained in the report,” the lawmakers said in a letter to Jo-Ellen Darcy, assistant secretary of the Army for civil works.

It was signed by seven senators and 24 House members. The group included members of both parties and at least one lawmaker from seven of the eight states within the Great Lakes region — Minnesota, Michigan, Wisconsin, Illinois, Ohio, Pennsylvania and New York. Only Indiana had no signers.

Jacqueline Tate, a spokeswoman for the Army Corps’ Great Lakes and Ohio River Division, said the agency had not received the letter and would have no immediate comment.

Whether to sever the man-made link between the Mississippi and Great Lakes systems is a divisive issue in the region.

Engineers reversed the flow of the Chicago River and built a 28-mile-long canal a century ago to flush the city’s sewage toward the Mississippi. The Chicago waterway system is now a 130-mile-long network of canals, rivers, navigational locks and other infrastructure.

Invasive species such as zebra mussels and round gobies have used the aquatic highway to migrate from the Great Lakes to the Mississippi and its tributaries. Now, Asian carp have moved up the Mississippi and Illinois rivers and are on the doorstep of Lake Michigan, held at bay by an electric barrier system. The corps says it’s working well, but scientists have detected Asian carp DNA beyond the barrier and critics say it’s not a long-term solution.

Michigan, Minnesota, Wisconsin, Ohio and Pennsylvania favor physically separating the basins and are suing in federal court to speed up the Army Corps study.

Business and government leaders in Illinois and Indiana have opposed separation, saying it would disrupt cargo shipping and pleasure boat operations in the waterways and cost the local economy billions. Four members of Congress from Indiana spoke against it after the report was released this week.

Supporters of separation say it’s the only way to protect the lakes’ ecosystems and a fishing industry valued at $7 billion.

“This action is necessary and achievable,” said Rep. Candice Miller, R-Mich.

Despite widespread opposition to separation in Illinois, two members of its congressional delegation — Sen. Richard Durbin and Rep. Mike Quigley, both Democrats — signed the letter to Darcy.

The letter does not specifically endorse any of the report’s alternatives or the idea of separation. But it notes that the report has information on engineering design, economic impacts, water quality and flood management that should help the corps move faster.

Posted 2/6/2012