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Debate: Should we reverse the flow of the Chicago River?

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Revision as of 21:11, 2 December 2010

Should we reverse the flow of the Chicago River?


Background and Context of Debate:

Prior to the 20th century, the Chicago River naturally flowed into Lake Michigan. Throughout the nineteenth century, however, raw sewage and pollutants dumped into the river (which then flowed freely into the lake) contributed to outbreaks of cholera, typhoid, dysentery, and other public health concerns. As a result, the Sanitary District of Chicago installed a system of locks throughout the watershed to reverse the flow of the Chicago River away from Lake Michigan. Today the Chicago Sanitary and Ship Canal, built in 1900, consists of 6 locks and it is the only shipping link between the Great Lakes and the Mississippi River. This system of locks allows for strategic operation at several points along the Chicago River and Chicago Area Waterway System (CAWS) to allow gravity flows from Lake Michigan to the Chicago River when the lake level is higher than the Chicago River (

Because of the threat of invasive species, including Asian Carp, from the Mississippi River, there has been significant debate about re-reversing the flow of the Chicago River back to its normal flow into Lake Michigan. The US Army Corps of Engineers has built an electric barrier aimed at stopping Asian carp from accessing the Chicago Area Waterway System (CAWS) at the Lockport Lock and Powerhouse site, but Asian carp DNA has been identified at entry points to Lake Michigan (

The US Army Corp of Engineers has requested $25 million to study potential separation strategies and their implications for the Chicago Area Waterway System (CAWS) (,)

This page evaluates the proposal of reversing the Chicago River back to its natural flow through a cost benefit analysis.

What are our policy options?


Four Feasible Solutions:

(1)Status quo of maintaining electric barrier—

(2)Engineer and release a toxin into the water to kill Asian carp

(3)—Genetically modify Asian carp to destroy digestive and reproductive capacity

—(4)Install a separation in the Chicago Area Waterway System that would eliminate water movement from a tributary of the Mississippi River, through the Chicago River and then the great Lakes

Separation is the only scenario that allows us to fully ensure that Asian carp and other invasive species will not access Lake Michigan as a result of our artificial shipping connection with the Mississippi River. The other policy options do not take into account the true threat that Lake Michigan faces from Asian Carp and other potential invasive species.

There are three sources of costs for this project:

(1) Engineering and construction costs to build new infrastructure and to shut down existing locks

(2) Regulation-related costs to treat water entering Lake Michigan

(3) Investment in infrastructure to offset changes in river-based transportation access.

Benefits of the project are halting the migration of Asian carp or other invasive species into Lake Michigan and the rest of the Great Lakes, greater conservation of water supplies in the Chicago River, and the use of the river for commercial and recreational transportation.

We measure the gross benefits of the project through estimated valuations of the above changes to the following primary markets:

(1) The fishing industry in Lake Michigan

(2) Water quality and supply

(3) Commercial and recreational transportation access

We believe that the benefits of re-reversing the flow of the Chicago River outweigh the costs, and we will trace our assumptions through the rest of this debate.


Separation Site Recommendation: Why the Lockport-Romeoville location?


Researchers have identified three locations for potential separation. The potential sites are the Lockport-Romeoville site, the Chicago River site, and the Calumet Region site.

We advocate for a separation lock system modeled on the Chittenden Lock in Seattle Washington at the Lockport-Romeoville site. This site is located farther south on the Chicago Area Waterway System (CAWS). It represents what we understand to be the simplest engineering solution and a foolproof way of installing a separation barrier. Thanks to a newly installed sterile boat lift modeled on a similar model recently built in Scotland, it will also still allow recreational boating beyond this new barrier on the Chicago-area waterways.

Although barge traffic will no longer be accommodated beyond this point and will have to be shifted to road and rail alternatives, we believe that the extra infrastructure investment and potential additional cost will be mitigated by other gross benefits.

Hydraulic Separation Structure

We propose a system of locks modeled on the Chittenden Locks in Seattle, WA, intended to mitigate the harm of invasive species. They were completed in 1916 at a cost of $3 million ($60 in 2010)[Bureau of Labor Statistics CPI Inflation Calculator: and “Lake Washington Ship Canal.” Retrieved at:] We assume total capital costs of $80 million, spread over years 1-5.

• We model O&M costs for the proposed structure on existing lock O&M costs. We assume annual operation costs for the new lock system is approximately equivalent to 1/3 of the operating costs for the 3 lock systems (6 locks at 3 sites) currently in use. O&M costs are as follows:

                 •$10.02 million annually for years 1-5 (status quo O&M until separation structure complete)
                 •$5.01 million annually for years 6-10 (O&M for new lock system plus 1 existing lock system to account for ongoing need for electric barrier in early phase)
                 •$3.34 million annually for years 11-25 (O&M for new lock system)


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What is the impact of separation on the cost of transporting goods?


The Chicago River currently provides a link between the Mississippi River and Lake Michigan; as a result there is a fair amount of barge traffic and recreational boating. Recreational boats will still be accommodated through the installation of a sterile boat lift, although barge traffic beyond the separation site will need to be accommodated through rail and road alternatives.

Recreational Boating

• We model our lift on the Falkirk Boat Lift, completed in Scotland in 2002 for a cost of £84.5 ($132 in 2002).[Falkirk Wheel website. Found at:] We will require a slightly more sophisticated lift. Hence, we assume total capital costs to be $183 million, spread over years 1-5.

• We assume O&M costs to be included in O&M costs for the hydraulic separation system.

Commercial Transportation

• The cessation of barge shipping will place undue strain on other existing transportation infrastructure, requiring the development of alternatives.

• We can expect an additional $27.5 million in maintenance costs for existing infrastructure in the event of no shipping.[Schweiterman, J. 2010. “An Analysis of the Economic Effects of Terminating Operations At the Chicago River Controlling Works and O'Brien Locks on the Chicago Area Waterway System.” Report, April 7. Retrieved at:] Hence, we assume any alternative pursued will cost less than this annual cost for a lifetime of 25 years (discounted at 5%). We assume capital costs for alternative transportation infrastructure to total $350 million, spread over years 1-5.


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What is the impact of separation on water supply and quality?


One benefit of the separation is increased water supply.

Though the Great Lakes hold 94 quadrillion gallons of water, there are strict limitations on how much water can be diverted out of them for ecological reasons (for example, low lake levels interferes with fish spawning grounds near the lake coasts). Because Lake Michigan is now a tributary of the Mississippi and the Gulf of Mexico, the water Illinois removes from the lake flows away from us after it is used, whether for agriculture, household use, to flush the Chicago Area Waterway System, or even when it falls as precipitation, which instead of being absorbed into the ground and running back to the lake joins the CAWS and flows away. Chicago’s diversion has been a contentious issue with the other Great lakes states and provinces since the original reversal. Other communities draw from the lakes for consumption, but they also treat that water and return much of it. They also face an arduous process - permission from each interested governing body - before they are allowed to divert water for other purposes. In 1967, the Supreme Court put a cap on how much water Illinois is allowed to divert from Lake Michigan in response to a lawsuit by the other Great Lake states. This cap was recently reaffirmed in the Great Lakes Compact, so it is unlikely to be raised any time soon. The cap means that we must treat the water supply as a finite resource. In 2005, a drought year, the lost storm water alone measured 588 million gallons every day (Metropolitan Planning Council and Openlands. Before the Well Runs Dry: Ensuring Sustainable Water Supplies for Illinois. November 2009). Separation would mean that water could flow back into the lake, though this depends on the technical details.

Estimating the value of this water is an interesting problem. Even with other necessities like food and shelter, value is measured by their market price. However, the price that people pay for water has little relationship to how much it costs to treat and transport it. For example, Chicago charges $2.00 per 1,000 gallons for all of its customers, even though it sells water to communities far from the city and distance makes it more expensive to do so. Water has some attributes of public goods, in that Realistically, the $2 value is very small. In reality, people often argue that water is so valuable that it cannot have a price put on it, and the result is that municipalities charge very low prices, which don't incorporate costs of provision. These prices don't reflect value, so $2 might be a good way to think about a lower bound on how to value the water gained by separation. If this is an appropriate measure, then the value of the extra water would be found: The price of treating water for drinking is .00067 and the city sells it for $2 per 1,000 gallons, so (588,000,000/1000)*365*2 - 588,000,000*365*.00067 = $285,444,600 of extra value a year. It is hard for people who live near one of the Great Lakes to think about water being scarce, but there are areas near Chicago that rely on aquifers that are beginning to be cost prohibitive to use. In January of 2010, 10 communities applied to the Illinois EPA for permission to create infrastructure and begin drawing from the lake, so another measure of the extra water's value might be found by examining how much those communities are willing to spend on it. In their feasibility study, the estimate for how much extra in taxes was $188 for the average resident, and the rate was to be set at $2.63 per 1,000 gallons (Northern Lake County Lake Michigan Water Planning Group. Lake Michigan Water Feasibility Study: Engineering Report. November 2007). So, (33510/1000)* 2.63 = $88. The annual tax will be $188, so annually they pay $276.12 for 33,510 gallons. Each 1,000 gallons is worth at least $8.24 to the Lake County residents who want Lake Michigan water, much more then the $2 that Chicago charges individuals. This means the 588,000,000 gallons a day has a value of at least 588,000,000*365*$8.24 = $176,832,285,840,000.

Again, there is no consensus about how to think about the value of water. These numbers may be very low, or they may be high considering the special nature of water. Organizations like the Natural Resource Defense Council (see Re-envisioning the Chicago River), and the Metropolitan Planning Council (see Before the Well Runs Dry) take the issue of water supply seriously, so it seems right to include this as a major benefit of separation.

Separation brings up some water quality issues that increase the project's cost, but which shouldn't be weighted 100% against the project.

The first is that separation removes an important flood control. Chicago's system takes storm water into the same pipes with raw sewage. Currently, when the sewage system is overwhelmed during a rainstorm, some flooding can be avoided by using the locks to temporarily reverse the system so that the storm water (mixed with raw sewage) is sent back into the lake. The Metropolitan Water Reclamation District has been working on a huge project to deal with floods called Deep Tunnel, which is supposed to almost eliminate the need to use this mechanism. However, climate change is predicted to increase flooding problems by bringing more intense storms. The Natural Resource Defense Council suggests that flooding fears may be overblown (see "Re-envisioning the Chicago River: Carp and courts update our thinking" blog post by Henry Henderson). They also suggest that a pilot study of green infrastructure projects could be used to offset extra flooding risks. This includes things like green roofs, replacing alleys with permeable surfaces, and even simple rain barrels. The study area in their Green Infrastructure pilot covered 1,880,000 square feet of impervious ground and reduced runoff volume (water that would otherwise flow into the sewage system) by 30% for $3,200,000 (National Resource Defense Council. Rebuilding Chicago's Stormwater and Wastewater Systems for the 21st Century: Understanding Hydrologic Conditions in the Region Technical Report. October 2010 and National Resource Defense Council. Response to Go To 2040 Comprehensive Regional Plan Draft. August 2010.

Would this completely solve the problem? With no information about what the actual changes would be in flooding risk, there's no way to know. The separation may make this project more urgent, but it isn't the only reason to carry it out so the entire costs of the project shouldn't be considered a cost of the separation. The city is pursuing similar projects already as a supplement to the Deep Tunnel project, and for their value in improving aesthetics, reducing energy use, and minimizing the urban heat island effect that creates very high temperatures in the summer.

The second water quality issue is that if water from the Chicago River is going into Lake Michigan, it has to meet much higher quality standards. The Metropolitan Water Reclamation District does not disinfect sewage - it is filtered, but it does not get filtered and the Chicago River has very fecal coliform counts. This leaves anyone who comes into contact with the water at risk for diseases like salmonella, and the river is marked with signs warning that no body contact is allowed (Wells, Rachel. "Disinfection dissatisfaction." Illinois Issues - A Publication of the University of Illinois at Springfield. March 2010). The MWRD is the only community on the Great Lakes that does not disinfect.

This should only count as a cost of the separation if there are no other reasons to do it. The Illinois Pollution Control Board is going to make a ruling soon on whether the MWRD is allowed to continue to not disinfect under the Clean Water Act which says that efforts have to be made so that recreation can occur "in and on" the water. It seems likely that this will happen - the exception was based on the water being so polluted or otherwise altered by humans so that it wasn't feasible to make it available for recreation. However, the Deep Tunnel project has greatly improved the quality of the water in the CAWS so that people have begun to use it for recreation. The IL EPA testified that "the fact that such recreational activities have been occurring in and on the water, not withstanding the various human caused conditions and hydrological modifications that Illinois EPA cites in support of the proposed recreational use designations, suggests that (1) such human caused conditions and hydrologic modifications do not in fact prevent attainment of recreation in and on the water in all segments of the CAWS and LDPR and/or (2) 4recreation in and on the water is likely to be attainable , if the water quality limitations impacting the use are remedied” (Testimony before Illinois Pollution Control Board, If the IPCB rules that disinfection must occur, then it is going to happen even without separation. Again, the separation makes disinfection more urgent, but it isn't the only reason to do it and its costs shouldn't be weighted 100%.


What is the impact of Asian carp on recreational and commercial fishing?


Asian carp pose a significant threat to the commercial and recreational fisheries of the Great Lakes (CRS/Great Lakes Fishery Commission). They are large, prolific, and consume vast amounts of food. Due to their large size, ferocious appetite, and rapid reproductive rate, Asian carp would disrupt the food chain that supports the native fish of the Great Lakes ( Although it is difficult to determine the magnitude of the impact, other regions in which Asian carp have been introduced can serve as a model for the Great Lakes. As Asian carp have dispersed and migrated within the Mississippi River Basin, they have displaced native fish to become the most abundant fish in a number of areas (CRS).

According to a 2007 study, avoiding an immediate 25% decline in fish abundance in the Great Lakes is worth approximately $87-$170 million annually (America’s North Coast) [Austin, John C., Soren Anderson, Paul N. Courant, and Robert E. Litan. 2007. “America's North Coast: A Benefit-Cost Analysis of a Program to Protect and Restore the Great Lakes.” Report commissioned by Healthy Lakes Healthy Lives, Healing Our Waters - Great Lakes Coalition, and Council of Great Lakes Industries. September. 29-31. Retrieved at:'sNorthCoastReport07.pdf].

Based off of this information, an expected value of $128.5 million in annual losses can be assumed. However, it is uncertain what percentage of decline would result from the introduction of Asian carp into the Great Lakes as well as how long it would take for this effect to occur. Several potential scenarios are listed below:

1) P(25% decline) = 0 for 10 yrs, and P(25% decline) = .25 for 15 yrs

           	PV= -$221 million, assuming r=.05

2) P(25% decline) = 0 for 5 yrs, and P(25% decline) = .25 for 20 yrs

           	PV = -$339 million, assuming r=.05

3) P(25% decline) = 0 for 10 yrs, and P(25% decline) = .5 for 15 yrs

           	PV = -$442 million, assuming r=.05

4) P(25% decline) = 0 for 5 yrs, and P(25% decline) = .5 for 20 yrs

           	PV = -$678 million, assuming r=.05

5) P(25% decline) = 0 for 10 yrs, and P(25% decline) = .75 for 15 yrs

           	PV = -$663 million, assuming r=.05

6) P(25% decline) = 0 for 5 yrs, and P(25% decline) = .75 for 20 yrs

           	PV = -$1.02 billion, assuming r=.05

In present value, the expected losses for the fishing industry range from a low estimate of $221 million to a high estimate of $1.02 billion. Assuming an equal likelihood of each scenario, the average of the present values produces an expected present value of -$560 million.


What is the impact of Asian carp on Great Lakes recreation?



What is the ultimate cost of the irreversible harm that Asian carp and other invasive species could wreak on the Great Lakes?


Asian Carp may become another huge stressor on a system that might not have the capacity to deal with any more stressors. Mayor Daley told the press that the re-reversal project could be the “salvation of the Great Lakes”, and it wasn’t complete hyperbole. Scientists fear that the Great lakes is at a tipping point where mass die offs will occur and the ecosystem will collapse. In “Prescription for Great Lakes Ecosystem Protection and Restoration: Avoiding the Tipping Point of Irreversible Changes”, a report endorsed by scientists and professors from across the Great Lakes region, the authors argue that “in large areas of the lake, historical sources of stress have combined with new ones to reach a tipping point, the point at which ecosystem-level changes occur rapidly and unexpectedly…” This means dead zones, rapid disappearance of organisms that form the basis of the food chain, and the elimination of major species such as lake trout. Even if Asian Carp aren't what does it, joining the waters put the Great Lakes in constant danger from invasive species, and it is a constant struggle to stop their spread. The costs of this may be greater far away from the Chicago area, which is part of what makes solutions so tricky. Lake Erie is already experiencing annual die offs, and has a dead zone that may be permanent. Lake Michigan's symptoms may be less severe, which makes it harder for people in the Chicago area to buy that the Great Lakes are in fact more threatened then ever. It is often argued that the Great Lakes are so damaged already; it isn't worth it to make efforts to restore them. However, it is valid to protect what is left of their ecosystem so that it remains available for the future, and it is valid to consider that the Great Lakes ecosystem has value in and of itself when thinking about whether the separation is a good project. It is false to say that nothing of value will be lost if the conditions in Lake Erie spread to large areas in each of the lakes. Even though the environmental conditions are uncertain, and there is no way to know how much capacity there still is for the lakes to absorb more stressors, it is worthwhile to start taking more care to avoid reaching the tipping point.

The authors of "America's North Coast" (a report written for the Brooking Institute's Great Lakes Economic Initiative) argue that a restoration of the entire Great Lakes would reap important economic benefits for a once flourishing region that has declined for many years. The report is a cost benefit analysis of the Great Lakes Regional Collaboration Restoration Strategy. They point to Colorado as an example of an area that has experienced great economic growth because of its natural characteristics. Colorado wasn't always a prosperous state, but because it can market a pristine environment, educated, mobile young professionals want to live there and prosperity has followed. An effective barrier between the Mississippi River system and the Great Lakes is an important piece of the GLRC strategy.

The Great Lakes are a natural wonder, and should be treated as such. They hold 20% of the world's fresh water, even including the inaccessible polar ice caps. They are home to interesting, diverse species of fish and other wildlife. Some of the fish species that are threatened if the Great Lakes are pushed past their tipping point are lake trout, lake sturgeon, and the American eel. Even though they are so damaged, many of the over 100 native species that still exist could be brought back from the brink with careful work and there are still some healthy areas left that could be protected. This is hard to place a monetized value on, but it does have to be part of the analysis.



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