Separation anxiety, Part 1 - Metropolitan Planning Council

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Separation anxiety, Part 1

Within the last few weeks the national media has taken a pointed interested in the concept of hydrological separation of the Great Lakes and Mississippi River basins—National Public Radio, the New York Times, and the New Yorker have all done detailed stories. This shift is a welcome change.  It's been about a year since the nefarious Asian carp burst into the public eye, and in that time public discourse has gone from jokes about crazy flying fish to a nuanced understanding that whatever solutions we determine for interbasin invasive species movement must also account for the realities of our region's freight, recreation, wastewater, and water supply goals.  After all, these fish (as well as many dozens of other potential invasive species) are swimming around in our region's sewer system, which also has a fair a number of boats in it.  If separation of the two watersheds is to occur, and there is no guarantee that it will or should, then any real solution is going to have account for the complexity of the system.

A map depicting northeastern Illinois' use of Lake Michigan water. Pumped at more than a dozen points along the coast, Lake Michigan water is pumped, treated, used, flushed, treated again, and ultimately released into the Chicago Area Waterway System, where it flows to the Mississippi River basin.

Whatever your opinion on Asian carp, there is no doubting the reality of invasive species movement through the Chicago Area Waterway System (and yes, there are other pathways species can move through, such as the Maumee River, but they don't flow through the middle of Chicago and run about two billion gallons of our wastewater off to the Gulf of Mexico every day).  We may not have yet lost the war against zebra mussels, sea lampreys and a host of others, but we're certainly behind on battles.  All told, invasive species and our efforts to combat them cost the U.S. an estimated $120 billion a year, and a good chunk of that is spent on protecting the Great Lakes and Mississippi Rivers, which are connected by our sewer system.

If all options are on the table, and that does seem to be the case, then hydrological separation merits investigation.  At the same time, this darn fish has given many reasonable people cause to wonder whether now might be the opportune to moment to rethink our region's relationship with Lake Michigan (our primary water source) and whether our current infrastructure is consistent with our 21st Century goals. I think we have five crucial goals for our waterways:

  1. Improve the water quality and ecosystems of Lake Michigan, Chicago area rivers, and the Mississippi Basin, through better treatment and reduced stormwater and combined sewer overflow effects.
  2. Provide clean drinking water for the growing Chicago region, easing reliance on strained aquifers and rivers.
  3. Enhance the capacity and efficiency of Chicago’s intermodal freight facilities.
  4. Sustain growth in recreational and tourism uses.
  5. Eliminate risk of interbasin species transfer.

So the big question is whether or not we can put our heads together and determine a separation scenario that facilitates all five of those goals.  Thankfully, there is now work underway to do just that.  Last Thursday I was fortunate enough to be part of the first stakeholder advisory committee for Envisioning a Chicago Waterway System for the 21st Century, a cooperative effort of the Great Lakes Commission (GLC) and the Great Lakes and St. Lawrence Cities Initiative (GLSCI).  The primary purpose of that project is to ask, "If we were to separate the watersheds, could we improve commercial transportation and water quality, and enhance flood control, tourism benefits, and recreation?"  That's pretty close the goals elucidated above (though my preference would be to determine whether we might also be able to return high-quality treated wastewater back the lake, as all of our Great Lakes neighbors do, and in so doing expand our available water supply).  

Perhaps we ask the question and the resulting answer is, "No, we can't do all of it at the same time."  In that case we might be forced to look to other long-term solutions, but nonetheless, the question is certainly worth asking.  The meeting established the guidelines for the study, and allowed everyone involved to weigh in on their goals.  I was happiest that there seemed to be consensus that our attention shouldn't be on the Asian carp, but on the longer-term and wholly certain threat of invasive species movement and what we can do about it.

The same day, the Natural Resources Defense Council (NRDC) released a white paper on some of the possible stormwater management implications inherent in separation—again, we are talking about our sewer system here.  Their study gives a concise accounting of how and when sewer overflows occur today, potential precipitation changes due to climate change, and the opportunities for green infrastructure to be a part of mitigating future flooding.  If separation were to happen, flooding is surely one of the issues we would need to address.  What NRDC and their consultant, Shaw Environmental, found was that in one sample neighborhood, a 50 percent reduction in impervious surface (through a combination of bioswales, rain gardens, and porous paving) would reduce stormwater runoff into the sewer by 30 percent.  The white paper is a quick and optimistic read, and a real contribution to our understanding of what would be entailed in a redesign of our region's water management.

Of course, planting trees and putting in porous pavement where it makes sense are things we should be doing anyway (don't forget Ill. Environmental Protection Agency has funding to help you do just that).  Likewise with improving our water quality, protecting our water supplies, increasing the efficiency of freight movement, and enhancing our the appeal of water-based recreation.  That's no mystery.  Can we do all that in way that also helps our Great Lakes and Mississippi River neighbors in the fight against invasive species?  Maybe.  We don't know.  I'm excited that we're finally trying to find out.  

The next meeting of the GLC/GLSCI study is in February, and I'll be sure to report back then.  Stay tuned.


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