Chicagoans were shocked last week to see a rust-colored substance from an Indiana water treatment plant ooze into Lake Michigan.

• But more dangerous and less publicized is the contamination that pours into Illinois waterways when farm chemicals — sometimes called nutrients — are washed off the land by heavy rains.

Why it matters: Water polluted with these chemicals [including nitrogen and phosphorus] can cause "blue baby syndrome," a condition that starves infants of oxygen. High levels have also been linked to cancer in adults.

• They can also reduce the amount of oxygen in the water, harming wildlife and causing algal blooms.
• By some estimates, Illinois runoff is responsible for 20% of the nitrate causing the growing dead zone in the Gulf of Mexico.

Driving the news: A new Illinois Environmental Protection Agency (IEPA) report shows these chemicals rising in our waters by double digits even though the state's goal was to reduce them by 45% by 2025.

Context: Environmental group The Prairie Rivers Network published a report this summer saying rural drinking water is under-tested for nitrate.

• High levels of nitrite have been found in public wells along the Illinois River but little testing is done on private wells.

Yes, but some of that was due to rain: Trevor Sample, the IEPA's Nutrient Loss Reduction Strategy coordinator, acknowledged that in the last five years, nitrogen levels were up 13% and phosphorus was up 35%. He also pointed out that water flow was up 25% due to increased rain.

• "When you have increased flow, you have increased runoff and you have increased nutrient loads," he tells Axios.

Looking forward: In a world where we expect more heavy precipitation events, there are still ways to prevent severe runoff.

• Sample says the IEPA is working to give farmers more education and resources, one being the Partners for Conservation cost-share program that, among other things, gives farmers money to use cover crops rather than chemicals to replace nutrients in their soil.
• More funding for that program could help since "the demand for it far exceeds what's allocated," Sample says.

👋 Justin here! I interviewed several Illinois politicians and journalists to help tell the story of former Illinois Speaker Michael Madigan, the longest serving state house speaker in U.S. history. The podcast comes out today in association with the Better Government Association.

• It includes stories from four governors, lawmakers and former staffers inside the Madigan organization.

Why it matters: Madigan stepped down earlier this year and is currently the focus of a federal investigation stemming from the bribery scandal at Commonwealth Edison (ComEd), though he has not been charged with any wrongdoing.

Flashback(s): He was famous for understanding the rules of the Illinois government better than anybody. This might be because Madigan wrote many of the rules and was a delegate at the Illinois Constitutional Convention in 1970.

Tidbits:

• Former Governor Jim Edgar named his heart attack after Speaker Madigan. He also recounts stories of lunches at the governor's mansion where all Madigan ate was an apple, cut up on a plate.
• Former Governor Bruce Rauner goes into detail about their monumental political fights, including a breakfast where Madigan said, "Bruce, I do two things. I manage power and make money from managing power."

The five-part series launches today and continues through October.

🚨 Crime fighters fighting! Cook County State's Attorney Kim Foxx claps back at Mayor Lightfoot. (ABC 7 Chicago)

👮‍♂️ CPD's chief David Brown says they need at least 1,000 recruits to stave off officer attrition. (Block Club Chicago)

Melissa speaks: Eric Ferguson's former co-host filed a lawsuit detailing workplace abuse. The Mix has pulled Eric off the air through October. (Robert Feder)

🎃 Trick or treat: Chicago will release guidance on Halloween later this week. So, no candy chutes this year? I'm still doing it. (NBC Chicago)

🏈 Bears running back David Montgomery is out for 4-5 weeks with a knee sprain. (ESPN)

Billionaire Republican donor Ken Griffin said Chicago was "like Afghanistan on a good day" on Monday afternoon.

• But Tuesday morning, readers of Condé Nast Traveler had a different descriptor: Best big city in the nation — for the 5th year in a row.

Why it matters: While Chicago suffers from a lot of problems — including unacceptable violence — it leaves a lasting and positive impression on travelers, at least the kind who fill out magazine surveys.

• That bodes well for the city's post-pandemic recovery.

By the numbers: The tourism bureau Choose Chicago says summer 2021 hotel occupancy rebounded to 51% on weekdays and 71% weekends, levels not seen since February 2020.

The driver: Visitors dig Chicago's architecture, dining, neighborhoods and entertainment, says Glenn Eden of Choose Chicago. But folks bragging about them on social media has also played a big role.

• "Word of mouth is what we live for and [seeing] other people's experiences is a big part of getting people to come to Chicago," Eden tells Axios.
• He says some of the most popular posts are pics from Chicago beaches, skyscrapers, the Art Institute and The Bean.
• "But also food," he says. "Let's face it, we also think with our stomachs and Chicago's culinary tourism is just off and running."

Speaking of The Bean: That's the name of a new chatbot that helps guide visitors to the city.

The Condé Nast Traveler also-rans:

2. New York

3. New Orleans

4. Boston

5. San Francisco

It's an oasis on the South Side where a person or creature might rise from the ashes. We will accept only the official name of this place.

Also: Tell us about your secret spots — places in Chicago you love and that more people need to know about.