U.S. Sen Mark Kirk and a host of local mayors are opposing a proposal to fight the spread of Asian carp.
The Army Corps of Engineers recently released report suggested that "hydrologic separation" of Lake Michigan and the rivers that feed into it would work to eliminate the threat of the invasive species.
The Army Corps says the task could take 25 years and up to $18 billion.
Environmentalists say steps must be taken so the carp don't further damage ecosystems.
Kirk, a Highland Park Republican, says the option of separating the waterways from the lake isn't financially responsible and he can't support it. Westchester Village President Sam Pulia says he's worried shutting down the rivers' locks will increase the likelihood of flooding.