The U.S. Army Corps of Engineers has released a costly final draft of its plan to keep invasive Asian carp out of Lake Michigan.
But environmentalists say it will be worth every penny.
The plan at the Brandon Road Lock and Dam, about 60 miles south of Chicago, would cost about $775 million.
Drew YoungeDyke is with the National Wildlife Federal. He says the cost, although dramatically higher than the Corps' first draft plan, would be a small fraction of the cost to the fishing industry, if Asian carp got into the lakes.
The Corps' plan involves constructing a redundant gauntlet of technologies to keep carp from getting past the lock and dam, including an electric barrier, an acoustic barrier, and a so-called "bubble curtain."
"The bubble curtain provides both an acoustic, visual and physical deterrent to fish trying to move through that bubble curtain of water," YoungeDyke explains.
Great Lakes states will have to put up 20% of the cost, and Congress would have to approve the other 80%.
Governor Rick Snyder says Michigan is willing to pay more than the other states, because it has coastline on four of the Great Lakes.
YoungeDyke says most people don't realize the full gravity of the threat.
"It's not just the Great Lakes that we have to worry about," says YoungeDyke. "It's every inland lake, it's every river. It's much bigger than most people realize."