Report outlines steps to keep Asian carp out of Great Lakes

A federal report released Monday proposes an array of technological and structural upgrades worth $275 million US at a crucial site in Illinois to prevent invasive Asian carp from reaching the Great Lakes and its vulnerable fish populations.

The U.S. Army Corps of Engineers outlined its tentative plan in a report that had been scheduled for release in February but was delayed by the Trump administration, drawing criticism from members of Congress and environmental groups.

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It analyzes options for upgrading the Brandon Road Lock and Dam near Joliet, a complex on the Des Plaines River southwest of Chicago that is considered a bottleneck where defences could be strengthened to prevent carp populations in the Mississippi River watershed from migrating into Lake Michigan.

Scientists say if the large, voracious carp become established in the Great Lakes, they could devastate the region's $7 billion US fishing industry by crowding out native species.

Minimizing waterway interference

The Army corps said the plan outlined in the 488-page document is intended to block the path of invasive species "while minimizing impacts to waterway uses and users." Elected officials and business leaders in Illinois and Indiana have said that significant changes to the Brandon Road complex could hamper cargo shipment on the busy waterway.

Among technologies the report endorses is using sound systems to create "complex noise" underwater that would deter fish from the Brandon Road area, plus installing a new approach channel and placing an electric barrier at its downstream end that would repel fish and stun them if they get too close. Brandon Road is several miles downstream from an existing barrier network.

Other measures would include installing water jets to wash away "small and stunned fish" that might be caught up around barges, plus a new lock where floating invasive species could be flushed away.

The report says the federal government would pay 65 per cent of the costs project's costs, with the rest coming from a "non-federal sponsor."

The corps will take public comments on the report until Sept. 21. After a feasibility study and series of federal and state reviews, a final report is scheduled for release in August 2019. Congressional approval and funding would be required to get construction underway.

"The Army Corps report makes clear that it's time for serious preventative actions to keep Asian carp out of the Great Lakes," said Howard Learner, executive director of the Chicago-based Environmental Law and Policy Center. "The ecological and economic costs of further delays are not sensible or acceptable."