As much as six inches of rain pummeled Champaign County last summer, flooding roads, basements and sewers and causing tens of thousands of dollars in repairs to residents’ homes.
“Any time it rains here, I always expect some flooding,” said Boyd, who lives on the corner of Russell Street and University Avenue in Champaign. “It’s been like this for years, but I’ve never seen anything like this before. I can’t get back what’s already been damaged by the water.”
Lustfeldt said ServiceMaster received 150 calls for flood damages after the July 12 rainfall, much more than the 36 flooding complaints received by the city of Champaign on the same day. It is unknown how many calls were made to the city of Urbana because the city does not make its log of flood complaints available to the public, assistant city engineer Brad Bennett said.
With the increase in development and heavy rains, the number of complaints about flooding has risen in Champaign. The public works department in Champaign has received 691 complaints since 2005. The number each year has varied widely, but 132 had come in as of last September compared with a total of 56 in 2013.
Both Champaign and Urbana officials said the frequency and intensity of heavy rainfall is nothing new. They said there is always the possibility that a heavy storm could result in flooding, and Eleanor Blackmon, the assistant civil engineer for Champaign, said the last major floods in Champaign before July 12 were in 2008 and 2009.
But the heavy rains in July will be far from the last, and the number of such rains will go up, state climatologist Jim Angel has said.
“We’ve seen a big increase overall in precipitation and more of the heavy rain events,” he said, attributing the increase to climate change. Angel cites records that date back to the late 1800s, with half the top 20 major rainfall events occurring between the 1970s to now. Angel said any rains more than three inches are classified as major rainfall events.
“Those are the ones that always give us the biggest headaches,” said Angel, who works for the Illinois State Water Survey. “From the historical data, we know that they’re becoming more frequent, and that ties into a pattern across the Midwest, so it’s not unique to Champaign-Urbana — it’s a regional pattern there.”
Both Angel and Don Luman, a geologist at the University of Illinois in Urbana-Champaign, said residential and commercial development has been a major contributor to the flooding.
“Development affects the flooding in Champaign-Urbana,” Luman said. “When there’s more concrete and less access to soil, the water runs and can’t be absorbed into the soil.”
According to U.S. Bureau of Census to date, 5,794 new building permits were approved in Champaign County from 2003 to 2013.
Green Street once routinely flooded until the first two phases of the $51 million Boneyard Creek detention project were completed in 2010.
Champaign planning and development director Bruce Knight was so confident of the solution that, in January 2013, he suggested Green Street business owners get rid of their flood insurance.
But Miriam Booth has owned Bankier Apartments on Green Street since the 1980s and says that flooding is still an issue, but it’s not nearly as bad as it used to be.
“We used to flood all the time, but since the Boneyard was put in, we only see flooding in the streets,” Booth said.
She said that after the completion of the first two phases of the Boneyard Creek project, flood maps were updated and her business was not considered to be in a flood zone. Thus, she said, her property no longer qualifies for national flood insurance.
Another project to prevent flooding was the Washington Street water detention project in the Copper Slough watershed and cost $15 million.
But in 2007, consultants estimated that it would cost another $25 million to improve and repair the Copper Slough, which runs for 16 miles from north Champaign into the Kaskaskia River, southwest of Windsor Road.
Both cities require new developments in Champaign and Urbana to have retention and detention ponds. Retention ponds store storm water permanently, whereas a detention pond typically drains after the peak of a storm has passed.
City using old flood data
Angel said detention ponds may not be as effective as planned, because the city’s flood data is not up-to-date.
“When engineers do design work, they plan for certain sized storms based on historical record, so they’ve been using reports that we did about 20 years ago on this subject,” Angel said. “And so it may be time to update some of those to incorporate more of the heavy rainfall events.”
City of Urbana Engineer Brad Bennett agreed with Angel. “Pipe and detention basin sizing are based on design storms that come from a statistical analysis of historic weather data. ”
Bennett said that it is much easier to analyze historic data than to predict future climate trends.
Champaign’s Civil Engineer Eleanor Blackmon said it is true that engineers in Illinois generally use the rainfall based on an Illinois State Water Survey study published in about 1990 that uses historic data back to 1901.
“I can’t speak to whether an update to include more recent data would increase the design storms or not,” she said. “As typical of the weather, the last 25 years have had very wet years and very dry years.”
Incentives for residents to install pumps
Bennett said the layout of historic Urbana does not leave very many options for the city to intervene, but the city has offered an expensive incentive for residents in historic Urbana to install overhead pumps in their basements to offset the rainwater.
Bennett said installing the additional pumps costs roughly $1,000 to $8,000 depending on the size and layout of the basement. The city of Urbana will pay for 75 percent of the installation costs up to $4,500.
Blackmon said Champaign also offers a similar incentive plan for its residents. Champaign imposed a storm water utility fee in 2013 to help fund costly flood infrastructure projects and $3 million annual upkeep. The fee brings in an estimated $2.8 million annually and helps pay down the city’s lingering debt from past projects.
Currently $70,000 of Champaign’s storm water budget goes to the incentive program, and the city has paid out more than $181,000 to 81 participants since 2008. Urbana has paid out at least $56,000 over the past five years for 21 residents.