Story URL: http://news.medill.northwestern.edu/chicago/news.aspx?id=218961
Story Retrieval Date: 4/17/2015 11:35:41 AM CST
Kate Van Winkle/MEDILL
The Chicago River -- plagued by drought, polluted by floods and covered in construction projects - faces its biggest threat 50 miles downstream. Asian carp have sent environmental groups and government agencies into overdrive as they work to prevent the invasive fish species from entering the Great Lakes via the river.
Proposed preventative measures include extremes such as a permanent and complete separation of Chicago-area waterways from the Mississippi River Basin. Several Great Lakes states are advocating for this solution, filing lawsuits calling the Chicago River a “public nuisance” and claiming it endangers Great Lakes ecosystems and economies.
The legal battle continues, despite dismissal in December of an interstate lawsuit by the U.S. District Court for the Northern District of Illinois. Wisconsin, Michigan, Minnesota, Ohio and Pennsylvania, the plaintiffs in the case, have already announced plans to appeal the decision in the case against the U.S. Army Corps of Engineers and the Metropolitan Water Reclamation District of Greater Chicago.
Separation, however, brings challenges and considerations beyond just stopping the invasion of Asian carp and other aquatic species.
“If you do something like that, you have to look at the impact on navigation,” said Lt. Col. Jim Schreiner, deputy district commander for the Army Corps Chicago District. “You're looking at water quality because there wouldn't be a natural reversal in total … and waste water treatment in the Chicago area.”
The Chicago District Army Corps is working in collaboration with the district and environmental groups to address the threat, both immediately and long term. The water reclamation district covers Cook County, treats wastewater and monitors water quality in Chicago waterways.
"We are providing technical support for the invasive species issue which is being studied by the U.S. Army Corps of Engineers, Great Lakes and Mississippi River Interbasin Study (GLMRIS) and the Asian Carp Regional Coordinating Committee," said David St. Pierre, district executive director.
Concerns regarding invasive species in Chicago waterways are nothing new, but recent developments have brought the debate to the forefront. Last July, the Canadian government released results from a risk assessment of Asian carp. The report showed Chicago-area waterways as the main point in which the species could spread to the Great Lakes.
The 16-month assessment by Fisheries and Oceans Canada and the Great Lakes Fishery Commission found that the Chicago Area Waterway System posed the biggest risk for invasion. Once inside Lake Michigan, the carp could spread throughout the lakes within 20 years with severe ecological impacts, according to the report.
“There are plenty of places in the basin where Asian carp could reproduce, there is plenty of food there, and they could eat the waste product of zebra mussels and other invasive species,” said Marc Gaden, communications director at the Great Lakes Fishery Commission.
“Within 50 years, the spread would be complete and the full implications and impact of this would be felt in the basin,” he added. “The disconcerting part of that is there is no way of controlling Asian carp and we’ll be watching this unfold for the rest of our lives.”
The corps has developed a four-part strategy to tackle aquatic invasive species problems. The electric barrier currently in place in the Chicago Sanitary and Ship Canal, near Romeoville southwest of Chicago, is part one. The barrier constantly pulses electricity to deter fish from nearing the locks, which maintain the flow of the Chicago River and allow boat traffic to navigate the waterway.
The system interconnects the Chicago River and Lake Michigan with the Des Plaines, Illinois and Mississippi rivers.
The second part is monitoring location. Telemetry, or tagging, is used to keep track of the numbers of aquatic species. Several hundred fish are currently tagged and the corps can track their movement up or downstream.
Efficacy studies make up the third part. These look at potential ways around the electirc barrier and if the electricity is working at its optimal parameters, Schreiner said.
Efficacy studies also include testing water samples for traces of environmental DNA, or eDNA, that signals the presence of Asian carp. Study results released in February suggest that the eDNA traces found in Chicago-area waterways are not from live Asian carp and do not indicate that an Asian carp invasion is imminent. EDNA testing in Chicago-area waterways began in 2010.
“These fish are miles and miles and miles away and the scientists have said that they haven’t moved north in six years,” said Margaret Frisbie, executive director of Friends of the Chicago River, a nonprofit that works to preserve and improve Chicago waterways environmentally and economically. “That really tells you that we have more breathing room to deal with these problems. It is still very serious and we’re committed to figuring out what the final strategies are, but hopefully lawsuits and threats of closing the Chicago locks are off the table.”
Closing the Chicago lock system pemanently is one proposed measure to prevent the spread of invasive species from the river system to Lake Michigan and the other Great Lakes. This solution, while creating a physical barrier to prevent invasive species transfer, would create significant problems when weighed against considerations such as shipping traffic, urban flooding and recreation on the river. Many are also concerned about the aesthetics of a building a concrete barrier in place of the lock system, which forms part of Chicago’s shoreline.
The Great Lakes Mississippi River Interbasin Study, called GLMRIS, is the fourth component of the corps’ strategy and addresses questions about long-term solutions for invasive species prevention. Possible solutions vary from complete separation of the Chicago and Mississippi water basins to maintaining existing preventative measures indefinitely.
“What [GLMRIS] is going to force us to do in 18 months is produce a suite of engineering solutions,” Schreiner said. “So right now, our engineers are in the process of going through planning avenues that include our federal and nonfederal partners to make sure we include all the species we should be going after and what are the engineering solutions we might apply to those types of problems.”
One proposed solution is simply maintaining the existing electric barrier. So far, this technology has been successful at preventing invasive aquatic species like Asian carp from entering the Great Lakes.
But the federal government mandates that one of the proposed solutions to be reviewed as part of the study is separation of the Great Lakes from the Mississippi River Basin, though the logistics of how to do so are still being researched.
The Chicago River was reversed more than 100 years ago, when concerns about water contamination and the spread of cholera prompted a massive engineering project to direct the flow of the river toward the Mississipppi. Originally, the river flowed into Lake Michigan, the city’s primary source of drinking water, causing constant contamination from sewage and waste dumped into the river. In the course of a few years, the corps constructed the lock and dam system and the Chicago Sanitary and Ship Canal, reversing the flow of the Chicago River and sending the city’s waste downstream to the Mississippi River Basin.
“Humans are pretty ingenious animals,” said Josh Ellis, program director for the Metropolitan Planning Council. “We reversed it one time through a massive feat of engineering, so there is no reason we couldn’t do it again.”
Ellis added that he understands the benefits of the separation and believes it should be investigated, but isn’t ready to make a decision on whether he supports the project fully yet.
Although the ship canal is the most obvious entryway for invasive species, it is possible for species transfer to occur by way of illegal trafficking, fishing, boating or alternate waterways.
“[A] complete disconnection would be a very costly undertaking, both monetarily and in terms of time,” said Dr. Solomon David, a postdoctoral research associate at the Shedd Aquarium. “Imagine if we were to still end up with Asian carp and other invaders in the Great Lakes via other, potentially more viable pathways.”
Asian carp are not the first species to threaten the Great Lakes’ natural ecosystem.
“Invasive species have been a major threat and presence in the Great Lakes for several decades,” David said. “We have only recently begun to understand their impacts in both long and short terms. Smaller species such as zebra & quagga mussels and round gobies can have major impacts … however, large ‘charismatic’ potential invaders such as Asian carp garner much more media attention.”
David said species such as zebra mussels “can affect Great Lakes food webs from the bottom up by consuming food usually consumed by smaller native organisms, therefore reducing available food for larger predators up the food web.”