Plenty of options, but no clear answers on next steps to prevent invasion of Asian carp into the Great Lakes
In a January study exploring ways to prevent the movement of invasive species such as Asian carp between the Great Lakes and Mississippi River systems, the U.S. Army Corps of Engineers offers plenty of options, but no definitive answers on what to do next. Reaction to the much-anticipated report, too, has highlighted continuing divisions in the region over how to attack the Asian carp problem.
“Any plan that falls short of permanent ecological separation leaves Michigan’s economy and ecology at risk,” Michigan Attorney General Bill Schuette said after release of the study.
In contrast, Illinois’ two U.S. senators oppose the idea of hydraulic separation, which would be accomplished through the construction of new physical barriers in the Chicago Area Waterway System.
The Army Corps estimates that such a project would cost up to $18 billion. The other options are to simply continue current Asian carp prevention efforts, implement new nonstructural control strategies, or move ahead with structural changes that don’t completely separate the Great Lakes and Mississippi River (new locks, electric barriers and treatment plants, for example).
“The study has good information and some new ideas, but falls short of giving us a path forward,” says Tim Eder, executive director of the Great Lakes Commission. “And that is frustrating, because it is what we’ve been searching for since 2007.”
In its analysis of the different options, the Army Corps rates hydraulic separation as the best way of stopping interbasin transfers, but also notes that this alternative is the most expensive, would take 25 years to complete and would essentially close off the Chicago Area Waterway System to commercial navigation.
Changes to this 128-mile system of rivers and canals are complicated by the fact that it is used in so many ways — for flood protection, sewage discharges, commercial navigation, recreational boating and power generation. The impact of hydraulic separation on these existing uses is behind much of the opposition to the idea. And it also significantly increases the cost of such an infrastructure project.
For example, if new physical barriers were built along the Lake Michigan lakefront, the Corps says new tunnels and reservoirs would have to be constructed to prevent widespread flooding. Or if such barriers were placed elsewhere, new tunnels and reservoirs would be needed to prevent untreated sewer discharges from flowing into Lake Michigan.
Consensus on hydraulic separation appears unlikely, but Eder is more confident about finding widespread support for new short-term strategies. For example, he says, a retrofitting of the Brandon Road Lock and Dam (part of the Chicago Area Waterway System) could add a significant layer of protection against the spread of Asian carp into the Great Lakes.
Current state and federal strategies to prevent an Asian carp invasion center on the use of electric barriers. A December 2013 federal study concluded that there was “no evidence that Asian carp are bypassing the barriers.” However, that same study warned of evidence that shows the use of electric fields in the water don’t always stop the movement of fish.
A 2012 binational study found that, if Asian carp were to enter the Great Lakes system, they would likely spread to all five lakes within a decade and have a severe ecological impact.
“The region needs to come together on an action plan,” Eder says.
|Stateline Midwest ~ February 2014||1.69 MB|