The view from Montrose Harbor. The intake to Chicago’s water system is visible in the top left. Image: Heather Phillips CC by/nc/sa

By Margaret O’Dell

Founded on the shores of the Great Lakes, which 18th-century French explorers called the “sweetwater seas,” Chicago recognized early the value of its access to the world’s largest freshwater system — for drinking water, transportation, recreation, industrial uses, and beauty.

But true to its commercial and industrial beginnings, Chicago has taken this natural wealth for granted. The fisheries, water quantity and quality, and wildlife of the Great Lakes have shown the effects.

The once-abundant Great Lakes commercial fishery, launched in the early 1800s, was virtually depleted by the mid-20th century. Today lake trout, which occupied the top slot in the Great Lakes food web, barely survives in Lake Michigan through the continuous introduction of hatchery-raised young. A still-thriving sport fishery relies heavily on introduced salmon.

Water levels in the Great Lakes fluctuate, based on variables such as water withdrawals, erosion, evaporation, and engineering that facilitates shipping but also hastens the flow of the water to the sea. Most of the water in the Great Lakes is the one-time-only legacy of the glaciers that created them; very little is replaced by rain or snowmelt.

As 40 million people have come to rely on the lakes for their drinking water, and ships on the St. Lawrence Seaway require deeper drafts, Chicago and other shoreline communities have become concerned about sustaining the amount and the quality of water in the Great Lakes.

(Image: Brian Koprowsky CC by/nc/sa)

Reversing the river

Past is prologue here: Chicago was established at the mouth of the Chicago River, and the river and Lake Michigan were an early dumping ground for raw sewage and other waste from the city. Fearing the potential for outbreaks of cholera and typhoid fever, between 1890 and 1900 the city and the state of Illinois undertook what was at that time the world’s most ambitious engineering project: they turned the river around.

By digging a 28-mile canal to the Illinois River, a tributary of the Mississippi, and installing a system of locks, engineers reversed the flow of the Chicago River. The new system of locks and canals conveyed Chicago’s sewage to the Mississippi River and ultimately to the Gulf of Mexico. It also facilitated barge traffic between the port of Chicago and the Mississippi system.

It was a bold solution to a public health problem, but at a cost: today, the “Chicago diversion” drains more than 2 billion gallons of water per day from Lake Michigan. It also created a conduit for invasive species such as the notorious Asian carp.

Chicago’s past has created other threats to water quality. A system of sewers built in the 1850s conveys both sewage and excess rainwater away for treatment. Ambitious in their day, they lack the capacity to manage current wastewater levels. Too much rain produces a “combined sewer overflow” that carries a mix of urban contaminants untreated into the lake and rivers.

But despite the heavy demands the city’s growth has placed on Lake Michigan, Chicago’s founders also valued their lakefront location for beauty and quality of life, taking “Urbs in Horto” (“city in a garden”) as the city’s motto. As early as 1835, public officials, civic leaders, planners, and developers worked together to protect the lakefront from development, declaring it “a public ground – to remain forever open, clear and free.”

Events such as the 1892 Columbian Exposition and the 1933 World’s Fair added to the system of parks and gardens. Today, parkland interlaced with beaches, marinas, bicycle and jogging trails, and nature sanctuaries stretches 26 continuous miles along Chicago’s lakefront.

(Image: Justin Kern CC by/sa)

Protecting habitat, conserving water

Fast forward to the 21st century, and Chicago struggles to address its legacy and balance its relationship with the Great Lakes in order to sustain its status as the “fresh coast city” for the future.

A variety of projects bring together public and private partners to protect and even expand habitat for fish and wildlife:

• Funding from the U.S. Environmental Protection Agency pays for restoring native fish habitat in shoreline communities.
• Thousands of citizen volunteers work through Chicago Wilderness, a network of public and nonprofit agencies, to remove invasive plants, reestablish native plants, and otherwise restore healthy habitat in forest preserves and parks throughout the region. Larger-scale projects like the Openlands Lakeshore Preserve north of Chicago not only preserve rare and endangered plant species but fight shoreline erosion as well.
• Lights Out Chicago, a partnership of the City of Chicago and Chicago Audubon, organizes commercial and residential buildings to dim their lights during migration seasons, preventing thousands of songbirds, attracted by shoreline parks but disoriented by bright city lights, and from dying in collisions with tall buildings

In 2008, the Great Lakes Compact was established by cities, states, and provinces to address concerns about water withdrawals, including growing suburbs outside the watershed whose used water does not return to the lakes. New rules for the withdrawal of water include conservation measures, limits on how far water can be transported, and a virtual ban on new diversions. The Compact remains controversial among excluded communities, which need more water in order to grow. And how sustainably Chicago manages its water supply will be a matter of scrutiny.

Chicago’s Metropolitan Water Reclamation District is responsible for treating wastewater and maintaining water quality. Pressed by the state and federal governments and by NGOs to address sewer overflows during heavy rains, MWRD will complete a Deep Tunnel by 2029 to better contain large amounts of contaminated rainwater; it has also agreed to disinfect the effluent it releases into the Chicago River.

Once unable to support life and unsafe for recreational use, the river is showing signs of renewal. Environmental agencies have upgraded its status, setting higher water quality standards. The MWRD has also agreed to use “green infrastructure” measures—such as permeable pavement, rain gardens and berms, and rain barrels—to divert rainwater before it reaches the sewers in order to reduce future overflows. Advocates for Chicago’s water, who had been fighting the district, are cautiously optimistic as they watch the river return to life.

Zebra mussels. (Image: SNM by/nc/sa)

Hydrologic separation

In the fight against invasive species, there are many enemies. Zebra mussels, a thumbnail-sized mollusk imported by ships’ ballast water from Europe in the late 1980s, cost shoreline cities millions by clogging water intake pipes and cooling systems. Over the past two centuries, 140 invasive species have entered the system, through ballast water, on boat hulls, and through deliberate import and accidental release.

Recently, attention has focused on Asian carp. These voracious bottom feeders and prolific breeders are using the same route created to redirect Chicago’s wastewater to make their way up the Mississippi River toward Lake Michigan. If the carp reach the Great Lakes, it is feared they will decimate the food supply, crowding out other fish.

An electric barrier 37 miles from Lake Michigan may stop them temporarily, but many stakeholders are calling for a more permanent solution: hydrologic separation. In effect, this would mean undoing the engineering feat of 100 years ago and cutting the connection between Lake Michigan and the Mississippi.

The Great Lakes-St. Lawrence Cities Initiative, a network of 82 shoreline municipalities from the U.S. and Canada, and the Great Lakes Commission, a similar network of states and provinces, have studied the feasibility, costs, and benefits of such a massive project. Former Mayor Richard M. Daley, who founded the Initiative, has expressed support for separation. Shipping interests are skeptical — they’ve come to rely on the connection. Other politicians worry about cost.

But advocates for the Great Lakes urge quick action, fearing that if even a few carp cross the barrier they will be impossible to stop. And, according to the U.S. Army Corps of Engineers, an estimated 38 other invasive species are poised to pass through the Chicago Area Waterway System, with devastating results for the ecosystem that receives them.

Looking to the future, a great unknown for Chicago and Lake Michigan is the impact of climate change. Some climate models predict the Great Lakes will be several inches lower by the end of the century. With warmer winters—Chicago has warmed an average of 2.6 degrees since 1980—surface water stays warmer, increasing evaporation, and coldwater-loving fish have to move into deeper waters.

A number of public programs seek to increase energy efficiency and speed the use of alternative energy sources. But Chicago is also focused on adapting to the inevitable changes, seeking to reduce the “urban heat island effect” by encouraging green infrastructure. The “city in a garden” aims to stay green and growing in the future, in harmony with its majestic sweetwater sea.

This image, photographed by crew of the International Space Station, features the Chicagoland area strung along the southwest shore of Lake Michigan. (Image: NASA)