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Choking Lake Michigan Until It Gives Up On Commerce

Dennis Byrne 9 June 2010 No Comment

Unable to convince the Army Corps of Engineers to shut down Chicago Waterway locks to keep Asian Carp out of the Great Lakes, some environmentalists are re-energizing another, and more drastic proposal—permanently sealing off the waterway from Lake Michigan.

The proposal would virtually undo what was considered a world engineering marvel at the beginning of the 20th Century: the reversal of the Chicago River. The engineering feat ended the public health plagues that were killing thousands in the young city caused by the dumping of rare sewage directly into Lake Michigan. It also created an all-water transportation link that propelled Chicago into the nation’s second largest city in a matter of decades.

Replacing the locks with concrete barriers at the mouth of the Chicago River or other places on the waterway is one of the proposals being pushed. All the proposals are costly and would seriously and negatively affect commercial shipping, recreational boating and the complex series of manmade channels and tunnels that are at the heart of the area’s water treatment and flood water systems.
The intent is not just to coral the Asian Carp on the Chicago Waterway side of the barriers, but to halt the migration in both directions of any non-indigenous species, from microorganisms to fish, between the two watersheds. Environmentalists have argued that failure to keep out non-indigenous life, such as lampreys, have caused incalculable damage to the Great Lakes ecology.
The proposals are outlined in a 2008 report, “Preliminary Feasibility of Ecological Separation of the Mississippi River and the Great Lakes to Prevent the Transfer of Aquatic Invasive Species.” The report was released by Alliance for the Great Lakes, which has taken up the slogan: “Make The Break: A Dead End For Invaders.”

The proposal for the complete separation of the two waterways got a boost last week when the Army Corps of Engineers last week announced that it had rejected proposals to close the locks for up to four days a week to stop the Asian Carp migration. Corps officials said a three-year study demonstrated that the shutdowns would not be an effective deterrent to keeping the fish out of the Great Lakes. The Corps, however, will temporarily close the locks when poisons are dumped in the waterway to kill the carp.

Some environmentalists welcome the decision because it will bolster their argument for permanent physical barriers. “The Alliance and other conservation groups say the only permanent solution is to restore the natural basin divide that once provided a physical barrier to alien species migration,” the group said. “We make the assumption that a hydrologic barrier, or complete elimination of all flow, at any location is the only way to guarantee 100 percent elimination of movement of all life stages of organisms via waterway routes.”

Under one proposal, commercial barges and recreational boats would be physically lifted over the concrete barriers, causing serious delays of commodity and other commercial waterborne transportation in the region. But the report cautions: “It is unclear if technology exists to move a loaded barge overland around a physical barrier without compromising the cost savings of barge movement. One concept is to combine isolation and sterilization of water with movement across canal segments.”

Also proposed are “dewatered locks” that allow shipping to continue between the two watersheds. As the locks are completely emptied of water, the vessel within would either come to rest on the “dry” lock bottom or on an “inflatable bladder.”

While recognizing that the permanent separation of the two watersheds could, in some cases, end commercial shipping to and through Chicago, the report justifies it by arguing that such tonnage is becoming less and less important.
The report, it should be noted, contains no cost-benefit analysis of undertaking a project that would change the region’s infrastructure in such a major way. The only nod to the question was this caution, buried in the report:

“Any separation strategy that relies on an alternate mode of transport for commodities must acknowledge the potential impacts on local transportation networks and environmental quality. A single barge loaded with 1750 short tons of material corresponds to 16 railcars or 70 semitractors/trailers. Additionally, rail and truck movements produce more pollutants per ton than barges while being approximately 30 percent and 75 percent less fuel efficient, respectively (Texas Transportation Institute 2007). The impacts of transitioning any volume of a commodity to an alternate mode should balance these factors against costs avoided by making the modal shift.”

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Dennis Byrne is a regular columnist for the Chicago Daily Observer

image O’Brien Lock and Dam, on the Calumet River

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