Elk Grove Village this week released the results of a feasibility study confirming that a proposal by the Friends of the Forest Preserves of Cook County on a way to alleviate flooding along Salt Creek in Cook and DuPage counties would work.
The environmental group suggested building an adjustable dam replacing the main dam at Busse Woods Reservoir -- built in 1976 to contain floodwater primarily from DuPage County -- as an alternative to an earlier proposal to expand the reservoir capacity.
The reservoir was designed to hold water in the forest preserves, but continually floods homes, businesses, and heavily-traveled roadways such as Devon Avenue, Elk Grove Mayor Craig Johnson said.
"That really interrupts commerce, and people trying to get to work, from work, emergency vehicles," Johnson said. "It's something we've been addressing for a long time."
A group of Northwestern University engineering students came up with the alternate solution for the friends group, which Elk Grove Village has been studying.
The idea is to manually lower the level of Busse Lake, which feeds into Salt Creek, before heavy rainstorms to allow the reservoir to hold more water, which then can be released at a slower pace, Johnson said.
To achieve that, the dam, located off Cosman Road, would have to be modified because it is locked and welded at its lowest elevation.
"It's locked that way and every day about an inch or two of water -- roughly 50 cubic feet per second -- goes over the top of it," Johnson said.
Johnson said with heavy rainfall, the water level in the reservoir rises about a foot, which then gushes downstream at roughly 200 cubic feet per second.
Salt Creek itself has capacity to hold a lot more water before it reaches flood stage.
"(The study) found that the amount of water Salt Creek can hold before it floods out of its banks is 1,000 cubic feet per second," Johnson said.
The idea is to lower the dam when it starts to rain to allow the creek to get to 1,000 cubic feet per second quickly. When the creek reaches its capacity, then the dam would be raised to contain any excess stormwater, Johnson said.
"It's actually a very ingenious idea, and you can eliminate a lot of the flood situations," Johnson said.
Johnson said the study found that out of 158 historic storms since 1950, Salt Creek has flooded 37 times, and 20 of those flood events could have been avoided with the proposed dam adjustment.
"Over half the floods we had in the past 60 years would not have occurred with this system in place," he said. "Out of the remaining 17 floods, 14 would have had minimal impact, three would have had some significant impact. Even if it does flood, it's going to be far less severe than it has been in the past."
Johnson said he spoke this week with the mayors of several DuPage County towns, including Addison, Elmhurst, Itasca, Roselle, and Wood Dale, affected by flooding from Salt Creek to gain their support for the proposal.
"They put in all those big reservoirs. We want to make this system work in conjunction with what they have now," Johnson said. "I think for once, after all these years, we may finally have a solution to a lot of the flooding problems that we've been facing."
Johnson said it would likely take two or three years for the various jurisdictions to get on board with the proposal and before a modified dam becomes operational.
The estimated cost for the dam modification is between $2 million and $5 million. The project could take a lot longer if federal funding is involved, Johnson added.
"It's not something that's going to happen in six months," he said. "But we're going to be pushing to make this happen as quickly as possible. This could be probably the biggest achievement that we've done as a (village) board in 16 years together."