Flooding in a drought year
After a frighteningly dry summer, record-low lake levels over the winter and a near shut-down of the Mississippi river due to low waters, it’s flood season. This week there were flood warnings in Lake County to the north of Chicago and in parts of the Illinois River to the west, and numerous rivers and streams hit flood or near-flood levels near the Quad Cities, Cairo and St. Louis.
The sudden flooding may be hard to absorb, but it’s a fact of living in a floodplain state. Illinois’ low lands and abundant rivers mean many parts of the state are liable to flood on a yearly basis, and the Chicago area’s history is marked by almost countless catastrophic floods.
So, is anything special about this year’s flood warnings? Well, yes and no.
“Typically, our flood season for the larger rivers is in the early spring,” said Bill Morris, a hydrologist at the National Weather Service. But this year, he said, areas north of Chicago had a frost depth down to ten inches during the melt and precipitation. “So when we had additional rainfall...that water basically hit a solid surface and just started running off into the streams.”
Morris said the runoff has the added consequence of preventing much-needed water from absorbing into parched, drought-stricken soil. To make a deeper dent in the drought we’ll need rain throughout the spring.
Flood or near-flood conditions have been even more widespread closer to St. Louis, but Mike Petersen of the U.S. Army Corps of Engineers St. Louis District agrees that it’s not unusual.
“I think what’s really alarming for folks is to see how quickly the river came up this year,” Petersen said.
In one day in the St. Louis area he saw the Mississippi rise ten feet due to a combination of increased water from snow melt in the north, and precipitation in the watershed. But rain doesn’t necessarily mean an end to drought.
“I think we are relieved to have some water in the river, but...we may end up facing low water conditions seeing as we’ve gone into this year with less water in the system than we started last year,” Petersen said.
Flooding in the greater Chicago area is a lot more complicated than what you might imagine when you hear about a flooded river; in that TV-ready scenario, the river overflows, and water creeps into streets and front yards.
But a lot of the flooding that strikes Chicago is flash flooding or sewer backups – the result of water filling up Chicago’s notorious combined sewer system. Dramatic summertime floods afflicted multiple Chicago neighborhoods in recent summers when sudden rains overflowed the city’s drainage system.
Beverly native Kathy Parker has lived in West Morgan Park on the far South Side for six years. In spring of 2011 her house flooded during a downpour, and her finished basement filled with several feet of sewer water. She cleaned for nearly two days straight, threw out a bunch of personal possessions, and thought she’d seen the worst of it. A month later, her basement filled up again.
She described a situation that may be grossly familiar to many Chicagoans.
“This time it was even worse, water just shooting like a fountain out of the drain, and everything imaginable and nasty in there,” Parker said.
She lost her my parents’ wedding albums in the flood. Her block was lined with dumpsters where neighbors tossed carpets, flooring and personal items.
Darlene Crawford of Calumet Heights tells a similar story. She’s lived on the Southeast Side for over 40 years with her family and has no desire to leave behind the house she bought shortly after marrying her husband.
“It’s a close-knit community and most of us have lived here, raised our children and now our grandchildren,” she said, “and a lot of our kids have moved back into this area.”
But not long after they moved into the house, their basement flooded for the first time. She says it has since flooded at least twenty times, not including instances of minor leaks.
“We didn’t know to ask, or to have a home inspection [before moving in],” she said.
But it wasn’t long before they realized, as Kathy Parker had, that the problem was community-wide.
“We found out that our house wasn’t the only house experiencing this type of problem. After a rain we would see the alleys just littered with household items,” Crawford said.
Crawford eventually came together with her neighbors to demand help from the city and the Metropolitan Water Reclamation District (MWRD), but she says most of the solutions she and her neighbors have adopted are individual: flood insurance, remodeling, changing how they use their basements for storage and installing individual drainage systems for homes.
“Nobody does anything about it”
Someone once said everybody talks about the weather, but nobody does anything about it.
Not so in the metro Chicago area. Cities and counties have no choice but to act on flooding; the amount of water that melts or precipitates in sudden bursts in an average Chicago spring or summer is too much to ignore.
Chicago’s faced with a problem related to the nature of its expansive and world-famous sewer system. The system, originally constructed in the 1800s, is what’s known as a combined sewer system: raw sewage and rainwater drain into the same pipes. Once upon a time, that drainage headed to the lake; now most of it goes through some treatment and separation, and gets deposited into waterways connected to the Illinois and Chicago Rivers. But during a storm, the whole system can become quickly overwhelmed, and when it overflows, the overflow (politely called a Combined Sewer Overflow or CSO by the MWRD) is a mix of rain water and raw sewage.
The MWRD has been working since the 1970s on what’s called the “Deep Tunnel” project or TARP (Tunnel and Reservoir Plan) that involves constructing a humongous system of tunnels, some as wide as 33 feet, connected to reservoirs designed to store overflow water. The 109 miles of underground tunnels are complete, but the last of the reservoirs won’t be complete until 2029. MWRD says the construction of the TARP has reduced the numbers of days with combined sewer overflows from 100 per year to 50 per year on average.
But Chicago floods may also be addressed by community-based and development solutions.
“It’s a collective problem, rather than just an individual property problem,” said Harriet Festing, director of the water program at the Center for Neighborhood Technology (CNT).
CNT is researching the prevalence and cost of flooding in the Chicago area by gathering insurance claim data and personal stories about flooding experiences.
“Forty-two percent of Cook County is impervious...that’s our parking lots, our streets, our sidewalks. And that’s just volumes of rain running off those areas and into our backyards and our basements,” Festing said.
As long as that volume of runoff has nowhere to go, using personal funds to build a more waterproof basement or better drainage in your own backyard is tantamount to swimming upstream in the Calumet River (and you don’t want to do that).
According to Festing, development that takes water runoff into account can go a long way in preventing increased flood risk in urban areas; rain barrels, rain gardens and small-scale projects in individual homes can also make a difference if they’re installed across an entire neighborhood.
MWRD has been taking public comments on a proposed watershed management ordinance since 2009, and plans to release a complete draft this spring. If passed, the ordinance would authorize a more proactive district-wide approach to new development that would better absorb storm water and protect people from flooding.
Not flooded out yet? WBEZ’s Chris Bentley has more on the links between flooding and climate change.
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