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New flood maps tell us we aren’t doing enough to stop rising waters

Chicago and the region need to step up fast to reduce flooding and protect inhabitants and businesses.

The Chicago River overflowed its banks and flooded the Riverwalk after overnight showers and thunderstorms across the city, Monday morning, May 18, 2020.
The Chicago River overflows the Riverwalk in mid-May.
Ashlee Rezin Garcia/Sun-Times

More than a century and a half ago, our low-lying city launched an ambitious undertaking to raise its buildings, streets and sidewalks by several feet to make room for sewers and to reduce flooding.

Now, a new model shows it’s time for another ambitious undertaking. The model, created by a group of academics and experts called the First Street Foundation, says the city of Chicago has the nation’s largest percentage of properties that are unexpectedly prone to flooding.

Clearly, Chicago — and the rest of the region, for that matter — has to step up quickly to reduce flooding and protect its inhabitants and businesses. In an era of climate change, rising water levels aren’t a problem limited to the coasts.

As reported in the New York Times, Chicago has 75,000 properties that are at risk of flooding, even though they don’t show up that way on Federal Emergency Management Agency maps. Englewood, for one, is particularly vulnerable.

FEMA says 0.3% of Chicago properties are at risk of flooding, but First Street says that number should be 12.8%. And this is in a metropolis that already has overflowing waterways, flooding basements, backyards that turn into lakes and roads that disappear underwater at times of heavy rains.

The same can be said of other parts of Cook County and the collar counties, according to First Street. You can assess your your own home’s flood risk by going to the First Street website at floodfactor.com.

The entire region is paying for doing too little to control flooding. The damage in recent years has run into billions of dollars.

The Lake Michigan shoreline also will be at risk if water levels — now near record levels — keep rising.

“Urban flooding is a huge issue for Cook County,” Kari K. Steele, president of the Metropolitan Water Reclamation District, said Thursday. “Even with having the capacity to store over a billion gallons of water, we still have an issue with residents getting water in their basements.”

Another recent report by Pro Publica said FEMA underestimates flood risk because insufficient funding means many FEMA maps showing flood-prone areas haven’t been updated for decades. The Center for Neighborhood Technology says most flooding now occurs outside FEMA’s official flood zones.

Moreover, many storm sewers are designed for “100-year storms,” which are so severe they should happen only once in a hundred years. But as storms get stronger, the 100-year storms become more frequent.

When people buy homes, it’s not obvious to them that storm sewers built years ago are too small for heavier storms that now occur because warmer air can hold more moisture. The sewers simply can’t carry all that water away fast enough, even if there is capacity in reservoirs and tunnels, and basements flood.

The Metropolitan Water Reclamation District’s ambitious Tunnel and Reservoir Plan, often called the Deep Tunnel, has been a step forward, but even when it is finished in 2029, heavier rains will already have increased the need for more water retention.

But the answer isn’t just to draw newer, more accurate maps. The region needs a widespread, coordinated effort to manage rainfall by using techniques that help it soak into the ground instead of running into the nearest storm sewer.

Tombstones sit in standing water on May 18 at Bohemian National Cemetery, 5255 N. Pulaski Rd., after Chicago recorded 8.3 inches of precipitation over the month and set a record for the wettest May in city history.
Ashlee Rezin Garcia/Sun-Times

To reduce the amount of water flowing into storm sewers and waterways, municipalities have installed permeable pavement, building owners have put up green roofs and homeowners have put in rain barrels and rain gardens. This summer, the MWRD is accepting applications from local municipalities and public agencies to partner in installing green infrastructure throughout Cook County.

But the efforts so far are too much like the proverbial drop in the bucket, and projects by one municipality can be undermined by neighbors with lax regulations. We need stronger regulations, more intergovernmental cooperation and widespread use of an array of engineering techniques that reduce runoff to manageable levels.

To develop a cohesive approach, as the Sun-Times reported in May, the Alliance for the Great Lakes, the Chicago Department of Planning and Development, the Chicago Metropolitan Agency for Planning, Friends of the Chicago River, the Cook County Forest Preserve District, the Lake County Stormwater Management Commission, the MWRD and other groups are creating a Chicago River Watershed Council to design ways to expand green infrastructure across the watershed and to expand and restore natural areas, which should help reduce flooding. We need to see more of this kind of thinking.

We now know we are at more risk of flooding than we thought. Let’s get to work.

Send letters to letters@suntimes.com.