The Bloomington City Council on Monday evening expressed an appetite to expedite the next two phases of the Locust-Colton sewer separation project and other measures in the wake of record flooding and sewage backups during heavy rainfall in late June.
Council members also asked staff to look at the cost of additional surveying and computer modeling of the sewer and storm water runoff system, potential construction of two new detention basins, and potential extra matching funding for a program that homeowners can use to pay part of the cost of sewage backup prevention mechanisms.
Public Works Director Kevin Kothe gave a presentation citing many causes for the flooding that affected thousands of homeowners, including: illegal sump pump connections to storm sewers; yard fences that disrupted drainage; window wells that filled up and leaked into homes; berms that trapped water and forced it to find its level in someone’s basement; flat topography on a plateaued ridge of land between channels like Sugar Creek in the middle of town and Little Kickapoo Creek on the east side that drains slowly; combined storm and sanitary sewers; sump pump failures or sumps that were overwhelmed by the sudden volume of water; and artifacts of the urban environment that concentrate water runoff faster than areas that have more "finger" waterways feeding into larger creeks.
The single biggest factor, Kothe said, was the record rainfall that weekend.
“There can always be a bigger event than will fit in a pipe,” said Kothe. “You can add more inlets and more infrastructure, but we already struggle to maintain what we have.”
The city has denied most flood claims, saying the 500-year weather event was an act of God. Some residents question whether that holds true for all the damage since some homeowners experienced just four inches of rain Friday evening, on June 25, and still had sewer backups. Kothe noted a heat map of areas of the city with the most damage reports does not correspond to a map of the areas that received the heaviest rainfall of eight to 10 inches.
“Even four inches of rain in an hour is very heavy,” said Kothe. “It’s not only the total rainfall, but also the amount recorded in a short period of time. By that measure, even some areas that had lesser amounts of rainfall were still off the charts” for state record books.
The areas with the densest reports of damage were the areas downstream from the highest rainfall totals, he said.
Kothe noted the city’s system of 475 retention basins (397 private and 78 public) that help control flooding can use some reassessment. Some worked as designed and held a significant amount of water before spilling over. Others did not fill to capacity. Kothe said those that did not fill are potential targets to direct more water.
He also said there are proposals to build two new detention basins, including one on West Washington Street at a Nicor remediation site. He said the utility will dig 25-30 feet deep to remove contaminated soil and that could be useful. The other potential site for a detention pond is downtown, at the city public services area on Lee Street. A potential third basin in the old west side Chicago And Alton rail yards would need study to determine whether it is suitable, Kothe said.
Combined sewers
The city’s large inventory of combined storm and sanitary sewers has drawn the most attention and residential ire in the weeks since the floods.
Kothe said the city could accelerate two of several more phases of the Locust-Colton sewer separation project by two years, to 2023, and use either low-interest loans from the EPA or city bonding to pay for it. He said other separation projects would need a broad study and modeling effort to determine the best bang for the buck.
The city also could consider enhancing funding for an existing sewer lift program that allows homeowners to reduce the chance of a sewer backup by pumping their effluent higher than grade and letting it flow downhill to the sanitary sewer entry. A rough average cost per homeowner is $10,000. Current city aid is about $4,500. Council members indicated some willingness to increase that amount.
Kothe was cautious about promoting creation of new storm sewer capacity during his briefing to the council.
“One of the challenges to a built-up environment is adding infrastructure gets expensive because there is already something there” he said.
One possible opportunity, he said, is along the Constitution Trail corridor because there isn't that dense underground infrastructure, and it is a path the city owns. That too would require deeper study, he said.
The menu options including construction of two detention basins, two phases of the Locust-Colton separation project, computer modeling, and potential additions to the homeowner sewer lift pump program tally a very imprecise $13 million. Council members asked staff to generate more reliable figures and proposals and indicated an eagerness to consider them as soon as next Monday’s meeting.
Also approved, though only by a narrow 5-4 vote, was council member Mollie Ward’s proposal to study a direct aid program and potential funding sources.
“There are people who are hurting,” said Ward. “We have people who have holes in their foundations that are big enough to drive a car through.”
She said some of those people do not make enough money to qualify for federal disaster loans and stand to lose their homes
"I believe we have a duty as public servants to assist people when they are hurting and are encountering problems like this," she said. “I’m calling on my fellow council members not out of any legal obligation, but from a moral obligation for us to step up and be the kind of people who care about our neighbors.”
Council members Donna Boelen, Sheila Montney, Nick Becker, and Tom Crumpler voted against studying the issue.
“I look at the Illinois constitution and it only seems to allow use of public funds for public purposes. I’m really concerned about using public tax dollars in a relief fund,” said Crumpler.
Others who were opposed, such as Montney, said they wanted to hear more discussion before directing staff to move forward on it.
Council member Jeff Crabill’s rejoinder was that the city can walk and chew gum at the same time. Supporters also said the estimated 10 hours of staff time to generate new data is minimal.
