advertisement

Lake Michigan a boon in climate change era, but faces some risks

It's easy for Illinois residents to take Lake Michigan for granted.

Only a sliver of the state fronts it, unlike Michigan and Wisconsin. Many residents might have only seen it on the occasional trip to Chicago. Even suburban residents go years, if not decades, without dipping a toe in it.

But changes in the climate change Lake Michigan. How much should you worry about that?

If you have lakeshore property, maybe a lot. Climate change seems to be leading to more dramatic swings in the lake's water-height cycle, according to Jennifer Caddick, vice president of communications and engagement for the Alliance for the Great Lakes, a nonprofit group devoted to protecting the Great Lakes.

If you live inland and are among the millions who drink, cook and water lawns with Lake Michigan water, maybe a little. Some forms of pollution are increasing, but Lake Michigan's depth helps protect against toxic algal blooms that have created dead zones or sent illness-causing bacteria into water supplies in other parts of the Great Lakes.

90% of U.S. fresh water

Lake Michigan is one of the five Great Lakes — the world's largest system of freshwater resources. The lakes — nicknamed the “Sweetwater Seas” — account for 19 percent of the world's fresh water and 90 percent of the fresh water in the United States.

Lake Michigan is the second-largest in volume, after Lake Superior. It is 307 miles long, 118 miles wide, and reaches a maximum depth of about 925 feet.

Breezes that pass over the lake in the summer are noted for cooling off downtown Chicago. Snowstorms passing over open portions in winter pick up moisture, hitting northwest Indiana hard with lake-effect snow.

The Illinois International Port District advertises the Port of Chicago as “America's Fourth Coast,” handling 19 million tons of cargo a year. Navy Pier says that more than 9 million people visited the entertainment attraction in 2016. We're justly proud of the efforts of architect Daniel Burnham and others, who persuaded politicians to put parks along much of the Chicago shoreline, rather than factories and docks.

Infrastructure threatened

Lake levels have gone through cycles before, according to historical records.

But scientists believe increasing warmth in the atmosphere in North America is leading to more compressed cycles, with higher highs and lower lows. High water levels eat away at beaches, retaining walls and other areas along the shoreline. The Chicago Park District has lost a North Side beach and sustained significant damage to two others and is beginning aerial mapping to study beach erosion.

“Those cycles are starting to change in unpredictable ways,” Caddick said.

When air temperatures are warmer, water temperature increases (and ice coverage decreases). Warm water evaporates more, especially in cooler air in the fall and early winter, according to a report from the Environmental Law and Policy Center. A more-saturated atmosphere leads to heavier, more violent storms. Warmer water helps harmful algae, and some invasive species such as quogga mussels, to thrive.

Increased precipitation, particularly heavier events, are increasing pollution flowing into the lake, over the ground and via sanitary-sewage releases, according to Caddick.

Some current sewage-treatment systems, especially combined stormwater-sanitary-sewage systems, can't handle the volume of more frequent, heavier storms, she said. To avoid having sewage back up in buildings, they open the gates at treatment plants and release untreated sewage into the lake, or into rivers that lead to the lake. “That's not good to have that extra pollution flowing into our rivers and lakes,” Caddick said.

Drinking water

What about our drinking water?

The Metropolitan Planning Council estimates that 6.6 million people in northern Illinois rely on Lake Michigan for drinking water. A 1967 Supreme Court decision enables Illinois to divert up to 2 billion gallons per day, through water plants, the Chicago River and several sewage and shipping canals. Much of the potable water flows through two city of Chicago plants, including 1 billion through the James W. Jardine Water Purification Plant, which is touted as the world's largest. Chicago's plants don't just serve the city; water from them is served up to residents of many Cook suburbs, and nearly all towns in DuPage County.

One of the other treatment plants belongs to the Central Lake County Joint Action Water Agency, in Lake Bluff.

The plant's interim director, Bill Soucie, doesn't expect climate change to significantly affect the agency's ability to deliver water. “It (the lake) just doesn't change that quickly,” Soucie said.

His agency draws an average of 19 million gallons a day. The intake devices are located 3,000 feet out from shore, and about 26 feet below the surface. Even if climate change puts more water in the Lake Michigan basin, that's an advantage to his agency; the more water on top of the intakes, the faster it flows to the treatment plant, he said.

Soucie said his agency hasn't experienced the troubles other areas throughout the Great Lakes have seen, such as toxic algal blooms. Harmful bacteria from a bloom forced the City of Toledo to turn off drinking water for three days in 2014. The blooms are caused largely by nutrient-laden fertilizer runoff, but warmer water temperatures help them grow, according to Caddick. The Chicago area might be less likely to face that problem, she said, due to much less fertilizer runoff and increased depth.

Indirect effect?

What if people further inland, running out of water in their aquifers, want to get Lake Michigan water?

The 2008 Great Lakes-St. Lawrence River Basin Water Resources Compact would prevent that. The compact, between the eight Great Lakes states, says that only areas that are in the Great Lakes basin can use its water. (The ability of Illinois plants to send Lake Michigan water to communities outside the basin is governed by the earlier court order.) Only parts of Cook and Lake counties are in the basin.

But if a lot of people moved here as climate refugees from areas having significant environmental changes, there could be issues. Illinois uses an average of 76 percent of its allocation, according to the Metropolitan Planning Council. And the Chicago Metropolitan Agency for Planning estimated in 2012 that 22 billion gallons of that was wasted — leaking out of pipes before it ever got to users. Replacing our crumbling public infrastructure would help, but the report notes a lack of willingness or ability to spend the money necessary to do so.

  Lake Michigan feels the effects of climate change in many ways, from higher water levels to increases in some kinds of pollution. Mark Welsh/mwelsh@dailyherald.com
  Lake Michigan, shown off Glencoe, feels the effects of climate change in many ways, from higher water levels to increases in some kinds of pollution. Mark Welsh/mwelsh@dailyherald.com
  Waves lap at a beach in Glencoe Friday morning. Higher water levels in Lake Michigan this year contribute to erosion. Mark Welsh/mwelsh@dailyherald.com
Article Comments
Guidelines: Keep it civil and on topic; no profanity, vulgarity, slurs or personal attacks. People who harass others or joke about tragedies will be blocked. If a comment violates these standards or our terms of service, click the "flag" link in the lower-right corner of the comment box. To find our more, read our FAQ.